4
National Emission Standards for Hazardous Air Pollutants
(NESHAP) for the Aerospace Manufacturing and Rework Industry
Background Information for Promulgated Standards
July 1995
N E S H A P
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National Emission Standards For Hazardous Air Pollutants
(NESHAP) for the Aerospace Manufacturing and Rework Industry
Background Information for Promulgated Standards
Emission Standards Division
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Air and Radiation
Office of Air Quality Planning and Standards
Research Triangle Park, North Carolina 27711
July 1995
u s Environment Portion
Reeton 5, Library (PL-12J) Floo.
77 West Jackson Boulevard, 12th Fiooi
IL 60604-3590
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ENVIRONMENTAL PROTECTION AGENCY
National Emission Standards for Hazardous Air Pollutants from
the Aerospace Manufacturing and Rework Industry - -
Background Information for Promulgated Standards
Prepared by:
Bruce C. Jordan (Date)
Director, Emission Standards Division
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
1. The final National Emission Standards for Hazardous Air
Pollutants (NESHAP) will regulate emissions of hazardous air
pollutants from cleaning operations; primer, topcoat, and
chemical milling maskant application operations; depainting
operations; and handling and storage of waste at aerospace
manufacturing and rework facilities. Only those operations
that are part of major sources under section 112(d) of the
Clean Air Act as amended in 1990 will be regulated.
2. Copies of this document have been sent to following Federal
Departments: Labor, Health and Human Services, Defense,
Transportation, Agriculture, Commerce, Interior, and Energy;
the National Science Foundation; and the Council on
Environmental Quality; members of the State and Territorial
Air Pollution Program Administrators; the Association of
Local Air Pollution Control Officials; EPA Regional
Administrators; and other interested parties.
3. For additional information contact:
Ms. Vickie Boothe
Policy Planning and Standards Group (MD-13)
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
Telephone: (919) 541-0164
4. Paper copies of this document may be obtained from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: (703) 487-4650
(NTIS;
U.S. EPA Library Services Office (MD-35)
U.S. Environmental Protection Agency
Research Triangle Park, N.C. 277111
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Electronic copies of this document may be obtained from the
EPA Technology Transfer Network (TTN). The TTN is an
electronic bulletin board system which is free, except for
the normal long distance charges. To access the aerospace
BID:
Set software to data bits: 8, N; stop bits: l
Use access number (919) 541-5742 for 1200, 2400, or
9600 bps modems [access problems should be directed to
the system operator at (919) 541-5384].
Specify TTN Bulleting Board: Clean Air Act Amendments
Select menu item: Recently Signed Rules
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TABLE OF CONTENTS
Section No. Page
1.0 SUMMARY
1.1 Introduction 1-1
1.2 Summary of Changes Since Proposal 1-9
1.2.1 Applicability 1-9
1.2.2 Definitions 1-10
1.2.3 Cleaning Operations l-ll
1.2.4 Primer and Topcoat Application Operations 1-12
1.2.5 Depainting Operations 1-14
1.2.6 Chemical Milling Maskant
Application Operations 1-16
1.2.7 Handling and Storage of Waste 1-17
1.2.8 Test Methods and Procedures 1-17
1.2.9 Monitoring Requirements 1-17
1.2.10 Recordkeeping and Reporting 1-18
1.2.11 Emissions Averaging 1-19
1.2.12 NESHAP Format 1-19
2.0 GENERAL ISSUES RAISED IN THE PUBLIC COMMENTS
2.1 Issuance of the CTG 2-1
2.2 Facility-Wide Emissions Averaging 2-3
3.0 APPLICABILITY ISSUES
3.1 Clarification of Applicability 3-1
3.2 Coverage of Non-major Sources 3-11
3.3 Regulatory Exemptions 3-20
3.4 Source Permitting 3-21
4 . 0 DEFINITIONS
4.1 Aerospace Facility 4-1
4.2 Aerospace Vehicle or Component 4-2
4.3 Chemical Milling Maskant 4-3
4.4 Chemical Milling Maskant Application Operation . 4-4
4.5 Cleaning Solvent 4-4
4.6 Coating 4-6
4.7 Coating Unit 4-6
4.8 Control Device 4-7
4.9 Depainting 4-8
4.10 Depainting Operation 4-9
4.11 Electrostatic Spray 4-9
4.12 Equivalent Organic HAP and VOC Content Level . . 4-10
4.13 Exempt Solvent 4-10
4.14 Flush Cleaning 4-11
4.15 Hand-Wipe Cleaning Operation 4-12
4.16 Hazardous Air Pollutant (HAP) 4-12
4.17 High Volume Low Pressure (HVLP) Spray Equipment . 4-13
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TABLE OF CONTENTS (Continued)
Section No. Page
4.18 Non-Chemical Based Depainting Equipment 4-14
4.19 Primer 4-15
4.20 Radome 4-16
4.21 Self-Priming Topcoat 4-17
4.22 Specialty Coating 4-18
4.23 Space Vehicle 4-18
4.24 Spot Stripping 4-21
4.25 Spray Gun 4-22
4.26 Stripper 4-23
4.27 Surface Preparation 4-23
4.28 Topcoat 4-24
4.29 Touch-Up and Repair Operation 4-24
4.30 Type II Etchant 4-26
4.31 Volatile Organic Compound (VOC) 4-27
4.32 Recommendations for Inclusion in the Rule .... 4-27
4.32.1 Cleaning Operation 4-27
4.32.2 Compliant Material 4-27
4.32.3 Confined Space 4-28
4.32.4 Electrodepainting of Paint 4-28
4.32.5 Inorganic HAP 4-29
4.32.6 Maintenance Painting 4-29
4.32.7 Mechanical Sanding 4-30
4.32.8 Organic HAP 4-31
4.32.9 Ozone Depleting Compound 4-31
4.32.10 Softener 4-31
5.0 CLEANING OPERATIONS
5.1 Housekeeping Measures 5-1
5.2 Hand-wipe Cleaning Solvent Requirements 5-5
5.2.1 Vapor Pressure Limits 5-5
5.2.2 Aqueous Cleaning Solvents 5-6
5.2.3 General Comments 5-8
5.3 Spray Gun Cleaning 5-13
5.4 Flush Cleaning 5-17
5.5 Exempt Operations 5-18
5.6 Deminimus Exemption 5-24
5.7 Applicability under Subpart GG and Subpart T . . 5-25
6.0 PRIMER AND TOPCOAT APPLICATION
6.1 Exemption Requests 6-1
6.1.1 Coatings 6-1
6.1.2 Application Operations 6-4
6.2 Deminimus Exemption Recommendations 6-9
6.3 MACT Floor 6-11
6.4 VOC and HAP Content of Coatings 6-12
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TABLE OF CONTENTS (Continued)
Section No. Page
6.4.1 General Comments 6-12
6.4.2 Emission Limits 6-14
6.5 Topcoats 6-16
6.5.1 Exterior Commercial Topcoats 6-16
6.5.2 Interior Commercial Topcoats 6-17
6.5.3 Self-Priming Topcoats 6-17
6.6 Primers 6-19
6.6.1 Flexible Primers 6-19
6.6.2 Commercial Exterior Primers 6-21
6.7 Proposed Application Methods 6-26
6.8 Alternative Application Methods 6-29
6.9 Touch-up and Repair Application Operations ... 6-30
6.10 Operation and Maintenance of Application
Equipment 6-35
6.11 Averaging Between Topcoats and Primers,
Controlled and Uncontrolled 6-37
6.12 Emissions Control 6-39
6.12.1 Control Efficiency 6-39
6.12.2 HEPA filter use 6-43
6.12.3 Hangar Use 6-50
6.12.4 Monitoring of Emissions and Shut-down
Requirements 6-51
7.0 DEPAINTING OPERATIONS
7.1 Exemption Request 7-1
7.2 Applicability 7-4
7.3 Dry Media Blasting 7-7
7.4 Chemical Stripping 7-13
7.4.1 HAP-containing strippers 7-13
7.4.2 Non-HAP strippers 7-15
7.5 Other Stripping Technologies 7-18
7.6 MACT Floor Determination 7-21
7.6.1 General Comments 7-21
7.6.2 Reduced Paint Scheme 7-23
7.6.3 Depainting of Private, Corporate, and
Small Aircraft 7-24
7.7 Organic HAP Emissions 7-27
7.7.1 General Comments 7-27
7.7.2 Emissions Control 7-29
7.7.3 Emissions During Periods of Equipment
Malfunction 7-32
7.8 Inorganic HAP Emissions 7-35
7.9 Particulate Control Efficiency 7-37
7.9.1 99 Percent Control Efficiency 7-37
7.9.2 Waterwash Booths 7-43
7.9.3 Monitoring Requirements 7-45
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TABLE OF CONTENTS (Continued)
Section No. Page
7.9.4 General Comments 7-46
7.10 Spot Stripping Exemption 7-47
7.11 General Comments 7-50
8.0 CHEMICAL MILLING MASKANT APPLICATION
8.1 General Comments 8-1
8.2 Exemption Request 8-2
8.3 Uncontrolled Maskants 8-3
8.4 Level of Overall Emissions Control 8-4
8.5 Maskant Usage with Type I and Type II Etchants . 8-5
9.0 HANDLING AND STORAGE OF WASTE
9.1 Need for the Standard 9-1
9.2 Basis for the Standard 9-5
10.0 COMPLIANCE DATES AND DETERMINATIONS
10.1 Compliance Periods 10-1
10.2 Compliance Extensions 10-11
11.0 TEST METHODS AND PROCEDURES
11.1 Use of Manufacturers' Data 11-1
11.2 Vapor Pressure 11-8
11.3 VOC/HAP Content Determination 11-14
11.3.1 Topcoats and Primers 11-14
11.3.2 Chemical Strippers 11-20
11.3.3 Method 24 11-21
11.4 Method 309 - Carbon Adsorption Efficiency . . . 11-24
11.5 Method 18 - Alternative Control Device
Efficiency 11-43
11.6 Method 5 - Particulate Control Efficiency
Determination 11-50
11.7 Transfer Efficiency for Coating Operations . . . 11-55
11.8 HAP Content Determination - Alternative
Procedure 11-62
11.9 General Comments 11-64
12.0 MONITORING REQUIREMENTS
12.1 Pressure Drop Parameter for Particulate
Filters 12-1
12.2 Alternative Monitoring Requirements 12-6
12.3 Catalytic Oxidation 12-7
12.4 Continuous Monitoring Requirement for
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TABLE OF CONTENTS (Continued)
Section No. gage
Particulate Filters 12-9
12.5 Reduction of Monitoring Data 12-15
12.6 General Comments 12-15
13.0 RECOKDKEEPING AND REPORTING
13.1 General Comments 13-1
13.2 Notification of Compliance Status 13-6
13.3 Retention of Records 13-8
13.4 Reporting Period 13-9
13.5 RCRA and Non-RCRA Waste 13-10
13.6 Cleaning Operations 13-12
13.6.1 Exempt Cleaning Operations 13-12
13.6.2 Compliant Cleaning Solvents 13-16
13.6.3 Spray Gun Cleaning 13-18
13.7 Primer and Topcoat Application Operations . . . 13-19
13.7.1 Averaged Topcoats and Primers 13-19
13.7.2 Compliant Topcoats and Primers 13-20
13.7.3 Emissions Control Devices 13-22
13.8 Depainting Operations 13-22
13.9 Chemical Milling Maskant Application Operations . 13-27
14.0 BASELINE/ENVIRONMENT IMPACT CALCULATIONS
14.1 Cleaning Operations 14-1
14.2 Depainting Operations 14-1
14.2.1 Chemical Stripping 14-1
14.2.2 Media Blasting 14-5
15.0 BASELINE/ECONOMIC IMPACT CALCULATIONS
15.1 Carbon Adsorption System for Chemical
Milling Maskants 15-1
15.2 Depainting 15-4
15.3 Primer and Topcoat Application Operations . . . 15-12
15.4 Cleaning Operations 15-16
15.5 Recordkeeping and Reporting 15-17
15.6 General Comments . , 15-21
16.0 OTHER COMMENTS
16.1 NESHAP Format 16-1
16.2 Publishing Proposed Rule in the
Federal Registey 16-4
16.3 Need for the Standard 16-5
16.4 RCRA Requirements 16-6
16.5 Delegation of Authority 16-6
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TABLE OF CONTENTS (Concluded)
Section No. Page
16.6 Amending Referenced Test Methods 16-9
16.7 Collection of Fees from Emissions 16-9
16.8 MACT Determination 16-10
16.9 Standards: General 16-13
16.10 VOC and HAP Emissions in Nonattainment Areas . . 16-15
16.11 Variance Provision 16-16
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1.0 SUMMARY
On June 6, 1994, the U.S. Environmental Protection Agency
(EPA) proposed national emission standards for hazardous air
pollutant (HAP) emissions from major sources in the aerospace
industry (59 FR 29216). These proposed standards implemented
section 112(d) of the Clean Air Act as amended in 1990 (the Act).
On November 22, 1994, the EPA announced in the Federal Register a
request for supplemental information and comment regarding the
level of control for chemical depainting operations,
applicability to general aviation, VOC and HAP content of
commercial exterior primers, the rolling material balance period
for proposed Method 309, regulation of chemical milling maskants
used with Type I etchants, use of HEPA filters to control
inorganic HAP emissions from topcoat and primer application
operations, and reduced recordkeeping requirements for a 2.1
Ib/gal low organic HAP primer. Public comments on the proposal
and these specific issues were requested in these two Federal
Register notices. There were 80 comment letters (see Table 1-1)
submitted by 61 different commenters, which consisted primarily
of facility owners and operators, trade associations, and State
and local air pollution control agencies. In addition, comments
were received from coating and cleaning solvent manufacturers, a
private environmental organization, and U.S. Government agencies.
Summaries of the comments, and the EPA's responses, are presented
in this document. This comment summary and the Agency's
responses served as the basis for the revisions made to the
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Table l-l.
LIST OF COMMENTERS ON THE PROPOSED
NESHAP FOR THE AEROSPACE INDUSTRY
Item Number in
Docket A-92-20 Cgmmenter. Affiliation, and Date
IV-D-1 John W. Walton, Tennessee AP Control Board,
Dept. of Env. and Conserv., Nashville, TN.
July 1, 1994.
IV-D-2 James L. Nolan, Director of Compliance, Puget
Sound APCA, Seattle, WA. July 19, 1994.
IV-D-3 Tom Kane, Polley-Kane & Associates, Inc.,
Floresville, TX. July 21, 1994.
IV-D-4 Bruce I. Bertelson, Manufacturers of Emission
Controls Assoc., Washington, DC.
July 22, 1994.
IV-D-5 David L. White, President, Paint Remover
Manufacturers Association, Vincennes, IN.
August 2, 1994.
IV-D-6 Julian Medina, Mgr. of Env. Affairs,
Chemtronics, Inc., El Cajon, CA.
August 3, 1994.
IV-D-7 David A. Ickert, Air Tractor, Inc., Olney,
TX. July 25, 1994.
IV-D-8 William M. Witzel, Tech. Manager, BASF
Corporation, Holland, MI. August 3, 1994.
IV-D-9 Michael J. Wax, Deputy Director, Institute of
Clean Air Companies, Washington, DC.
August 5, 1994.
IV-D-10 Kip Keenan, Mgr. of Env. Resources Dept.,
Electronic Systems Group, Westinghouse
Electric Corp., Baltimore, MD.
August 5, 1994.
IV-D-11 Beverly Hartsock, Deputy Exec. Director,
Texas Resource Conservation Commission,
Austin, TX. August 4, 1994.
IV-D-12 William 0'Sullivan, Administrator, Air
Quality Regulation Program, NJ Dept. of EPE,
Trenton, NJ. August 5, 1994.
1-2
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TABLE 1-1. (Continued)
1-3
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TABLE 1-1. (Continued)
IV-D-13 John Ellis, President, Kal-Aero, Inc., Battle
Creek, MI. August 3, 1994.
IV-D-14 Roger Randolph, Acting Director, Division of
Env. Quality, Missouri Dept. of Nat.
Resources, Jefferson City, MO.
August 5, 1994.
IV-D-15 Sheldon I Weinstein, President, AC Products,
Inc., Placentia, CA. June 30, 1994.
IV-D-16 Richard Baumer, Air Force Materiel Command,
Wright-Patterson AFB, Ohio. July 21, 1994.
IV-D-17 Mark Halvorsen, Technologies Sikorsky
Aircraft, Stratford, CT. July 28, 1994.
IV-D-18 Cyrus A. Jaffari, President, Malek, Inc., San
Diego, CA. June 23, 1994.
IV-D-19 Cyrus A. Jaffari, President, Caspian, Inc.,
San Diego, CA. July 19, 1994.
IV-D-20 Ashok Chaurushia and Charles Bajza, Northrop
Corp., Hawthorne, CA.
IV-D-21 Tracy Garrett, Jr., on behalf of Steve
Harrington, Southeastern Regional Mgr., Deft,
Inc., Irvine, CA. July 8, 1994.
IV-D-22 Katy Wolf, Exec. Director, Institute for
Research and Technical Assistance, Santa
Monica, CA. August 22, 1994.
IV-D-23 Donald F. Theiler, Chairman, STAPPA Air
Toxics Committee, STAPPA/ALAPCO, Washington,
DC. August 24, 1994.
IV-D-24 Tracee L. Gamel, Geraghty & Miller, Inc.,
Austin, TX. August 23, 1994.
IV-D-25 Gwendolyn K. Feltis, Gardere & Wynne, L.L.P.,
Tulsa, OK, (on behalf of American Airlines).
August 30, 1994.
IV-D-26 Roswell Dennison, Chairman, Env. Council,
Gravure Assoc. of America, Rochester, NY.
September 13, 1994.
IV-D-27 Joe Downing, Corporate Env. Specialist, Texas
Instruments, Inc. September 13, 1994.
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TABLE l-l. (Continued)
IV-D-28 Michelle I. Ritter, Senior Atty., PPG
Industries, Inc., Pittsburgh, PA.
September 19, 1994.
IV-D-29 Glynn Rountree, Director of Env. Affairs,
Safety & Health, Aerospace Industries Assoc.,
Washington, DC. September 14, 1994.
IV-D-30 R. E. Hammond, Director of Env. Management
Division, National Aeronautics and Space
Administration, Washington, DC.
September 15, 1994.
IV-D-31 David M. Driesen, Project Atty., Air and
Energy Program, Natural Resources Defense
Council, Washington, DC. September 14, 1994.
IV-D-32 J. H. O'Brien, Staff Vice President, Env.
Affairs, Lockheed Corp., Calabasas, CA.
September 12, 1994.
IV-D-33 Robert D. Fletcher, Chief, Toxic Air
Contaminant Control Branch, CA Env.
Protection Agency, Sacramento, CA.
September 14, 1994.
IV-D-34 P. Michael Peck, President, Dynamold
Solvents, Inc., Fort Worth, TX.
September 13, 1994.
IV-D-35 Elsie L. Munsell, Deputy Assistant Secretary
of the Navy, Washington, DC.
September 14, 1994.
IV-D-36 William A. Minter, Vice President,
Environmental, Health and Safety, Sikorsky
Aircraft Div., Stratford, CT.
September 9, 1994.
IV-D-37 Richard K. Ketler, Senior Atty., Air
Transport Assoc. of America, Washington, DC.
September 15, 1994.
IV-D-38 Stephen P. Risotto, Exec. Director, Center
for Emissions Control, Washington, DC.
September 15, 1994.
IV-D-39 H. Allen Irish, Counsel, National Paint &
Coatings Association, Washington, DC.
September 13, 1994.
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TABLE 1-1. (Continued)
IV-D-40 John A. Johnson, Vice President, The Boeing
Company, Seattle, WA. September 15, 1994.
IV-D-41 Russell W. Kroll, Attorney, Doerner, Stuart,
Saunders, Daniel, Anderson & Biolchini,
Tulsa, OK, (on behalf of NORDAM).
September 15, 1994.
IV-D-42 Mike Lake, Chief, Engineering Division, San
Diego Air Poll. Control District, San Diego,
CA. September 14, 1994.
IV-D-43 Pat Leyden, Deputy Exec. Officer, South Coast
Air Quality Management District, Diamond Bar,
CA. September 15, 1994.
IV-D-44 John A. Dege, Manager, Air Programs, DuPont
SHE Excellence Center, Wilmington, DE.
September 16, 1994.
IV-D-45 Robert A. Accarino, Director, Env., Health &
Safety, BF Goodrich Company, Akron, OH.
September 15, 1994.
IV-D-46 John Grainger, Dir. of Tech. Services, Turco
Products, Inc., Elf Atochem North America.
September 12, 1994.
IV-D-47 W. Caffey Norman, III, Patton Boggs, L.L.P.,
Halogenated Solvents Industry Alliance,
Washington, DC. September 15, 1994.
IV-D-48 David P. Page, Gardere & Wynne, L.L.P.,
Tulsa, OK (on behalf of American Airlines and
Textron Aerostructure). September 22, 1994.
IV-D-49 Raymond F. Pelletier, Director, Office of
Env. Guidance, Dept. of Energy, Washington,
DC. September 20, 1994.
IV-D-50 Russell W. Kroll, attorney, Doerner, Stuart,
Saunders, Daniel, Anderson & Biolchini,
Tulsa, OK, (on behalf of NORDAM).
September 15, 1994.
IV-D-51 James T. Reed, Supervisor, Env., Health and
Safety, Learjet, Inc. September 14, 1994.
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TABLE 1-1. (Continued)
IV-D-52 Milton Feldstein, Air Poll. Control Officer,
Bay Area Air Quality Management District, San
Francisco, CA. September 15, 1994.
IV-D-53 Stephen P. Risotto, Exec. Director, Center
for Emissions Control, Washington, DC.
September 26, 1994.
IV-D-54 Mike Sheptak, Mgr., Engineering Departments,
Verbatim Corporation, Sunnyvale, CA.
September 13, 1994.
IV-D-55 Tim Owens, Manager, Corporate Env.
Engineering, Morgan Adhesives Company, Stow,
OH. September 15, 1994.
IV-D-56 Robert J. Schwinghamer, Deputy Dir. for Space
Transp. Sys., and Alex A. McCool, Mgr. of
Space Shuttle Proj. Office, National
Aeronautics and Space Administration,
Marshall Space Flight Center, AL.
September 19, 1994.
IV-D-57 William E. Ruxton, Vice President, The
National Tooling & Machining Association,
Fort Washington, MD. September 15, 1994.
IV-D-58 Richard S. Zbur, Latham & Watkins, Los
Angeles, CA (on behalf of The Regulatory
Flexibility Group). November 10, 1994.
IV-D-59 David P. Page, Gardere & Wynne, L.L.P.,
Tulsa, OK (on behalf of American Airlines and
Textron Aerostructure). June 30, 1994.
IV-D-74 John Grainger, Dir. of Tech. Services, Turco
Products, Inc., Elf Atochem North America.
December 15, 1994.
IV-D-75 Cyrus A. Jaffari, President, Caspian, Inc.,
San Diego, CA. December 8, 1994.
IV-D-76 David M. Driesen, Project Atty., Air and
Energy Program, Natural Resources Defense
Council, Washington, DC. January 5, 1995.
IV-D-77 Dale L. McKinnon, Technical Director,
Manufacturers of Emission Controls
Association, Washington, DC.
January 4, 1995.
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TABLE 1-1. (Continued)
IV-D-78 John Grainger, Dir. of Tech. Services, Turco
Products, Inc., Elf Atochem North America.
January 3, 1995.
IV-D-79 Kraig Kurucz, Group Lead, Air Quality
Compliance, Environmental Protection
Programs, Lockheed Missies & Space Company,
Inc., Sunnyvale, CA. January 3, 1995.
IV-D-80 Glynn Rountree, Director of Env. Affairs,
Safety & Health, Aerospace Industries Assoc.,
Washington, DC. January 4, 1995.
IV-D-81 Charles L. Robertson, Senior Environmental
Engineer, Environmental Compliance, Bell
Helicopter Textron, Inc., Fort Worth, TX.
January 5, 1995.
IV-D-82 Tim Sturdavant, Environmental Engineer
Specialist, Environmental Affairs Department,
Rohr, Inc., Chula Vista, CA.
January 3, 1995.
IV-D-83 Elsie L. Munsell, Deputy Assistant Secretary
of the Navy, Washington, DC.
January 5, 1995.
IV-D-84 W. Caffey Norman, III, Patton Boggs, L.L.P.,
Halogenated Solvents Industry Alliance,
Washington, DC. January 6, 1995.
IV-D-85 Richard K. Ketler, Senior Atty., Air
Transport Assoc. of America, Washington, DC.
January 6, 1995.
IV-D-86 Stephen P. Risotto, Exec. Director, Center
for Emissions Control, Washington, DC.
January 6, 1995.
IV-D-87 Cameron Drake, Business Development Manager,
CAE Electronics, Ltd., Quebec, Canada.
January 5, 1995.
IV-D-88 John A. Johnson, Vice President, The Boeing
Company, Seattle, WA. January 6, 1995.
IV-D-89 Mike Lake, Chief, Engineering Division, San
Diego Air Poll. Control District, San Diego,
CA. January 6, 1995.
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TABLE 1-1. (Concluded)
IV-D-90 Gwendolyn K. Feltis, Gardere & Wynne, L.L.P.,
Tulsa, OK, (on behalf of American Airlines).
January 6, 1995.
IV-D-91 Stephen P. Risotto, Exec. Director, Center
for Emissions Control, Washington, DC.
January 6, 1995.
IV-D-92 Mike Lake, Chief, Engineering Division, San
Diego Air Poll. Control District, San Diego,
CA. January 6, 1995.
IV-D-93 John J. Scialdone, Polymers Section,
Materials Branch, National Aeronautics and
Space Administration, Goddard Space Flight
Center, Greenbelt, MD. January 6, 1995
IV-D-94 John A. Johnson, Vice President, The Boeing
Company, Seattle, WA.
January 13, 1995.
1-9
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standards between proposal and promulgation. This document is
volume II of "National Emission Standard for Hazardous Air
Pollutants (NESHAP) for the Aerospace Industry - Background
Information for Proposed Standards," June 1994 (later referred to
as BID, Volume I) (docket item III-B-1). This report also
includes a discussion of the changes made to the regulatory
analysis for the proposed standards presented in BID, Volume I.
1.2 SUMMARY OF CHANGES SINCE PROPOSAL
Several changes of varying importance have been made to the
standards since proposal. The majority of the changes were made
in response to the public comments, but some were made by the EPA
to improve clarity or consistency. Listed below is a summary of
the major changes and clarifying revisions made in developing the
final standards.
1.2.1 Applicability
The final rule now specifically states that aerospace
vehicles that leave the Earth's atmosphere are not covered under
this rule. The rule also clarifies that only items critical to
the structural integrity or flight performance of the vehicle are
regulated. Also, aircraft transparencies (windshields) and
electronic parts and assemblies will not be covered. These types
of vehicles and components were never intended to be included in
the NESHAP. Finally, the applicability section states that
material usage associated with research and development, quality
control, and laboratory testing is not being regulated.
In addition, the final rule specifies that formulations
containing HAP or VOC at concentrations less than 0.1 percent for
carcinogens or 1.0 percent for noncarcinogens, as determined from
manufacturer's representations, are not covered by the standards.
The final rule also includes an exemption for low-volume
coatings. Up to 50 gallons per separate formulation of coating
may be used and the total facility usage of low-volume coatings
must not exceed 200 gallons annually.
Since data are not presently available to serve as a basis
for regulation of smaller sources, the final rule will not
regulate non-major sources (no change from proposal).
1-10
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1.2.2 Definitions
The EPA has revised the definition of "chemical milling
maskant application operation" to clarify that only maskants used
in Type II etchants will be regulated. Maskants used with Type I
etchants and additional specialty coating maskants are being
addressed in the control techniques guideline (CTG) for the
aerospace industry.
Several commenters stated that more than one coat of primer
may at times be applied. Therefore, the definitions of "primer"
and "self-priming topcoat" have been revised to include the first
layer of coating and any subsequent layers of identically
formulated coating.
The definition of "specialty coating" now includes a
specific list and definitions of the specialty coatings that are
exempt under the final rule (Appendix B). The aerospace CTG
under development will contain recommended VOC content limits for
these coatings.
The EPA has deleted the 4 ftVvehicle specification in the
"spot stripping" definition. The EPA believes that the
definition is adequately descriptive without a size limitation.
The EPA is also deleting this size specification from the
depainting standard. The 4 ft'/vehicle limit for "touch-up and
repair operations" has also been deleted, due to the difficulty
of determining the total area touched up on a specific vehicle.
A definition for "cleaning operation" has been added to the
rule. This definition adds clarity to the cleaning standard by
grouping all of the cleaning operations together.
"Electrodeposition of paint" has also been added to the list
of definitions. This paint application method has been accepted
as an equivalent MACT level of control for coating emissions.
The definition for "depainting" has been revised to exclude
hand and mechanical sanding, and any other processes that do not
emit airborne particulates during depainting, from the depainting
standard.
The EPA agrees with commenters that "mechanical sanding" is
a depainting method that minimizes the release of HAP's. A
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definition for "mechanical sanding" has been added to the rule.
A definition for "softener" has also been added. Several
commenters stated that they use softeners in conjunction with dry
media blasting as a depainting method. The final rule does not
prohibit the use of non-HAP paint softeners.
The final rule also contains definitions for "aircraft
transparency," "carbon adsorber," "carbon adsorber control
efficiency," "confined space," "control system," "high efficiency
particulate air (HEPA) filter," "inorganic hazardous air
pollutant (HAP)," "natural draft opening," "nonregenerative
carbon adsorber," "organic hazardous air pollutant (HAP)," "space
vehicle," "temporary total enclosure," "total enclosure," "two-
stage filter system," "waterwash system," and nomenclature for
determining carbon adsorber efficiency. These definitions were
added to the final rule to improve the clarity of the regulation.
1.2.3 Cleaning Operations
The EPA has revised the housekeeping measures in the
cleaning standard to exempt non-HAP, non-VOC solvents from the
standard. As one commenter pointed out, water could
theoretically have been regulated by the proposed provision and
this was not the EPA's intent. Additionally, cotton-tipped swabs
have been exempted from the housekeeping measures because these
application devices represent a source of minimal emissions.
The EPA has also revised Table 3, "Composition Requirements
for Approved Cleaning Solvents," and added the term
"photochemically reactive" to the composition requirements for
hydrocarbon-based cleaning solvents. This action deletes acetone
and any compounds which the Agency may deem non-photochemically
reactive in the future. Also, a minimum flash point of 200°F has
been adopted as a requirement for aqueous cleaners. The previous
requirement, "aqueous solutions must be non-flammable and non-
combustible," has been deleted. The EPA believes that this
revision will make compliance with the standard much more
straightforward.
In addition, the EPA has added a pollution prevention
alternative to the emission limits specified in Table 3. A
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facility may demonstrate that the volume of hand-wipe solvents
used has been reduced by 60 percent using a baseline established
by the permitting authority. The facility must demonstrate that
this alternative compliance plan will achieve emissions
reductions equivalent to the cleaning solvent composition
requirements.
The section on hand-wipe cleaning has been revised to
specify that spray gun cleaning performed in accordance with the
work practice standards is not subject to the cleaning solvent
composition and vapor pressure specifications in the rule. The
EPA believes that this revision clarifies the standard by stating
that spray gun cleaning will be regulated by work practices and
not by cleaning solvent composition limitations.
The flush cleaning provision has also been revised. The EPA
believes that when a facility uses an aqueous cleaning solvent
for flush cleaning, the emissions will be minimal. Therefore,
the EPA has exempted facilities that use aqueous cleaners for
flush cleaning from the flush cleaning requirement.
1.2.4 Primer and Topcoat Application Operations
The EPA has listed the specialty coatings that are exempt
from the Primer and Topcoat Application Operations standard in an
appendix to the final rule. By listing the specialty coatings
and accompanying definitions, the EPA believes that the public
can clearly identify the coatings that are covered by the
standard. While the specialty coatings have not been regulated
in the NESHAP, they will have VOC content limits specified in the
CTG.
Aerospace vehicles and components that are intended for or
on permanent public display will also be exempt from the rule.
The EPA believes that coating of these vehicles will represent a
minimal source of emissions.
The EPA has also added waste handling and storage
requirements for primers and topcoats. These requirements
represent common sense initiatives with respect to emission
reductions.
One commenter stated that technology developments for self-
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priming topcoats may not follow the developments for topcoats in
general. The EPA agrees and has listed self-priming topcoats as
a distinct category in the standard, with the same organic HAP
and VOC limits as specified for general topcoats.
The time period for facilities using averaging to achieve
compliance with the VOC and HAP content limits has been changed
from daily to monthly. This change in the averaging time period
must be approved by permitting authority. In addition, the
permitting authority will retain the right to limit the time
period used for averaging and each averaging scheme must be
approved in advance by the permitting agency as part of the
facility's title V permit.
The EPA has also added a provision that allows facilities to
operate application equipment according to their own specified
operating instructions. The company must still use one of the
acceptable application methods and may not operate the equipment
when the application generates emissions that are greater than
produced using the manufacturer's specification.
"Electrodeposition (dip) coating" and "cotton-tipped swab
application" have been added as acceptable coating application
methods. Electrodeposition achieves a transfer efficiency
equivalent to or better than HVLP and use of cotton-tipped swabs
produces minimal emissions.
The EPA has added "airbrush" to §63.745 (e) (3) (i) as an
acceptable method of application in limited access spaces. The
EPA believes that the definition of "limited access space"
sufficiently eliminates the potential for misuse of the
application method.
The EPA also added "aerosol spray can application" to the
list of situations that are exempt from the requirement to use
specific application techniques due to the minimal emissions
resulting from this process.
The EPA has listed three-stage or HEPA filters as the
standard for topcoat and primer application operations at new
sources when the coatings being applied contain chromium or
cadmium. The EPA has also listed two-stage filters as a MACT
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standard for existing source topcoat and primer application
operations. The final rule also states that the coating
application operation must be shut down and corrective action
taken when a waterwash system used to control emissions from the
application operation is not operated according to manufacturer's
specifications.
The EPA has added "sealant detackifying" as an exemption to
the inorganic HAP emissions provision, because the emissions from
this source are minimal. In addition, facilities may gain an
exemption from the inorganic emissions control requirements for
specific parts if the parts are listed in the title V permit and
approved by the permitting authority.
1.2.5 Depainting Operations
The EPA has exempted from the standard, aerospace vehicles
and components that are on permanent public display and cannot be
readily moved. The EPA recognizes that such vehicles cannot be
readily positioned in an enclosed area for depainting.
In addition, the EPA has reorganized the standard into two
sections: requirements pertaining to facilities using non-HAP
processes for depainting aircraft and requirements for facilities
that generate organic HAP emissions when the primary method of
depainting is the use of HAP-containing chemical strippers.
The EPA has exempted hand and mechanical sanding from the
inorganic HAP emissions control requirements in the final rule.
These methods generate minimal airborne HAP emissions and
installing controls on these operations would be cost-
prohibitive.
During malfunctions of non-chemical based depainting
equipment, the EPA will now allow a facility 15 days of
substitute materials use on an annual basis as opposed to the 14
days per malfunction in the proposal. The EPA believes that many
facilities will choose to use HAP-containing chemical strippers
during malfunctions, necessitating the reduction in the number of
days that substitute materials may be used. A facility may
always use non-HAP depainting techniques or methods for an
indefinite period of time during equipment malfunctions.
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When non-chemical based depainting equipment is used, the
EPA will allow a facility to operate the equipment according to
manufacturer's specifications or to locally specified operating
*
instructions. The EPA understands that some facilities have
developed their own set of specifications due to the
incompleteness of the specifications supplied by some equipment
manufacturers. The EPA believes that such facilities have
maximized the equipment's performance and likely minimized HAP
emissions.
Several commenters stated that the reported control
efficiencies for inorganic HAP emissions resulting from media
blasting were based on manufacturer's claims and not test data.
The EPA agrees and has deleted the 99 percent control efficiency
requirement for dry particulate filters used with media blasting
equipment. The EPA has implemented a set of work practices in
lieu of a control efficiency standard. The EPA has also deleted
Method 5 testing for dry particulate filters. The final rule
specifies work practices when dry particulate filters or
waterwash booths are used to control emissions from media blast
depainting operations. Additionally, particulate filters and
waterwash booths will be required only for media blasting (i.e.,
not for hand or mechanical sanding). Furthermore, the EPA is
currently evaluating the effectiveness of different types of
particulate filters and test methods to quantify the control
efficiency of the filters. Once the EPA has determined an
effective test method, the Agency will issue a supplemental
proposal in the Federal Register and request comments on
requiring affected sources to utilize particulate filters that
are EPA-approved based on tests performed by the filter
manufacturers.
The depainting spot stripping exemption has also been
clarified. Only facilities that use non-HAP depainting methods
may use the exemption. If a facility chooses to use HAP-
containing chemical strippers as the primary depainting method,
then the final rule requires that control devices be installed on
the process. If controls are installed at a facility, then the
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EPA believes that all HAP emissions should be controlled,
including emissions from spot stripping. A commercial facility
may use up to 26 gallons of HAP-containing stripper per aircraft
depainted, calculated on an annual average basis. A military
facility may use up to 50 gallons of HAP-containing stripper per
aircraft depainted. When a facility exceeds these emission caps,
the resulting emissions must be controlled.
The EPA has added the use of HAP-containing chemical
strippers (with appropriate controls) as an acceptable depainting
method. If a facility chooses to use chemical strippers that
contain HAPs, the resulting emissions must be controlled at an
overall efficiency of 81 percent for existing control systems and
95 percent or greater for control systems installed on or after
the effective date of the NESHAP (promulgation date). In
addition, the 95 percent control efficiency can be achieved as a
combination of emissions capture and control equipment and
reduced chemical stripper usage. Emissions reductions would be
calculated using 1996 and 1997 chemical stripper usage as the
baseline.
1.2.6 Chemical Milling Maskant Application Operations
The EPA has added waste handling and storage requirements
for chemical milling maskants. These requirements represent
common sense initiatives with respect to emission reductions.
The EPA has also exempted the application of maskant to
touch-up marred and scratched surfaces from the standard. The
EPA believes that touch-up of scratched and damaged surfaces
represents a source of minimal emissions.
The time period for facilities using averaging to achieve
compliance with the VOC and HAP content limits has been changed
from daily to monthly. This change in the averaging time period
must be approved by permitting authority. In addition, the
permitting authority retains the right to limit the time period
used for averaging and each averaging scheme must be approved in
advance by the permitting agency as part of the facility's title
V permit.
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1.2.7 Handling and Storage of Waste
The EPA has deleted §63.748(b) which states, "store all
waste that contains organic HAP in closed containers," since the
docket does not contain sufficient data to implement this
provision for non-RCRA waste. However, the general housekeeping
provision applicable to handling and transfer of HAP-containing
waste has been retained.
1.2.8 Test Methods and Procedures
The EPA has added an equation to the "vapor pressure
determination" paragraph to assist facilities in determining the
vapor pressure of hand-wipe cleaning solvents. The equation
identifies all variables that are used in the vapor pressure
determination.
The EPA has also revised equation 8, which is used to
calculate the VOC content of topcoats and primers. An additional
variable has been defined, (Vxl) , and incorporated in the
denominator, in order to account for exempt solvents contained in
the coating. This revision corrects the definition of (GJ ; the
ENDFIELD
mass of VOC emitted per volume of coating i (pounds per gallon)
less water and exempt solvents as applied.
Method 309 has been deleted from the final rule for
determining the efficiency of carbon adsorbers. The final rule
contains provisions that specify the requirements for determining
the efficiency for regenerative and nonregenerative carbon
adsorbers.
The EPA has deleted the use of Method 5 to determine the
particulate filter control efficiency. The EPA is currently
working to develop an effective testing methodology that
correlates control efficiency with particulate size distribution.
1.2.9 Monitoring Requirements
The EPA has specified in the final rule that dry particulate
filters are to be monitored using pressure drop as the monitored
parameter. The pressure drop limits during proper operation
should be specified by the filter manufacturer. The EPA has also
deleted the requirement that pressure drop be monitored for
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waterwash booths. Waterwash booths will be monitored using
visual checks in combination with the water flow rate limits
specified by the manufacturer of the booth.
The EPA has added continuous emission monitors (CEM), as an
alternative procedure for determining the destruction efficiency
of incinerators. Facilities may now use OEM's
to demonstrate incinerator efficiency by monitoring the
effluent composition. As long as the composition remains
constant, a facility will not be required to recalibrate the
temperature sensors.
The final rule also contains monitoring requirements for
carbon adsorbers. The requirements specify that the parameters
used to determine the overall control efficiency of the carbon
adsorber system should be monitored.
1.2.10 Recordkeeping and Reporting
The EPA has included a provision that requires a facility to
inform the Agency of the facility's plan with respect to its use
of coatings within 2 years of promulgation and no later than 12
months prior to the final compliance date.
As mentioned earlier, the EPA has deleted the provision
requiring enclosure of all waste that contains HAP. Accordingly,
the recordkeeping and reporting requirements corresponding to
this provision have also been deleted.
The EPA has also revised the provisions pertaining to
cleaning operations. A facility is no longer required to keep a
log of the parts, assemblies, and subassemblies cleaned with non-
compliant solvents. Instead, a facility must report the
processes where these non-compliant hand-wipe cleaning solvents
are used. Additionally, the facility is required to record the
monthly volume of non-compliant cleaning solvent used instead of
the daily requirement in the proposal. The EPA will also only
require records and reports for cleaning solvents containing HAP
or VOC.
As mentioned earlier, the EPA has changed the averaging
period for uncontrolled primers, topcoats, and maskants, from
daily averaging to monthly averaging. Therefore, the final rule
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requires that the volume of coating used each month and the
monthly volume-weighted averages be recorded instead of recording
the daily volume usage and daily volume-weighted averages.
In addition, the EPA has added a provision for "low HAP
content" primers. These primers contain less than 2.1 Ib/gal of
VOC or HAP and annual records of the total volume purchased must
be recorded.
The EPA has exempted facilities from the reporting
requirements if their total use of chemical strippers is 50
gallons or less per year.
1.2.11 Emissions Averaging
The final rule does not contain a comprehensive program for
averaging across multiple source categories. The Agency is
currently evaluating various averaging schemes and options and
intends to solicit public comments on an averaging plan in a
supplemental proposal to the NESHAP.
1.2.12 NESHAP Format
The EPA has removed the tabulated summary of the rule from
the text and added it as an appendix to the final rule. The EPA
believes that this revision will ensure that owners and operators
read the rule text in order to determine the rule's applicability
to their facility.
In addition, the EPA has included a list of the exempt
specialty coatings and accompanying definitions as an appendix to
the final rule.
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2.0 GENERAL ISSUES RAISED IN THE PUBLIC COMMENTS
2.1 ISSUANCE OF THE CTG
Comment: Five commenters (IV-D-29, IV-D-32, IV-D-35,
IV-D-39, IV-D-51) supported the development and issuance of a
control techniques guideline (CTG) to define RACT for aerospace
operations, as expressly required by the 1990 Clean Air Act
Amendments. Three commenters (IV-D-29, IV-D-35, IV-D-51) noted
that although the primary environmental benefit will be achieved
through the Aerospace NESHAP, the development of the CTG still
has the benefit of providing uniform guidance to State and local
agencies. Commenter IV-D-51 stated that the issuance of a CTG
will assist local regulatory agencies in administering the
standard and will help provide a more level playing field within
the industry. Commenter IV-D-29 stated that based upon
discussions during the June 30, 1994 CTG meeting and the August
15, 1994 public hearing, it is their understanding that the EPA
will release a draft CTG for public comment.
Commenter IV-D-35 noted that section 183(b)(3) of the Clean
Air Act requires the EPA to issue an aerospace coatings CTG.
Commenter IV-D-32 requested that the EPA fulfill its legal
requirement to issue a separate CTG for certain low-usage
coatings, such as adhesives, sealants, and specialty coatings.
Three commenters (IV-D-29, IV-D-35, IV-D-39) urged the EPA
to recognize the importance to the industry of separately
proposing the CTG and providing opportunity for public comment.
Commenter IV-D-39 pointed out that in the preamble, the EPA
has indicated that rather than issue a separate 'draft CTG in this
case, it is simultaneously soliciting public comment on draft
best available control measures (BACM), which are proposed to be
the same as the proposed MACT for coatings and solvents. The
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commenter also noted that comments received on the proposed MACT
rule are also to be considered in formulating a final BACM.
While the commenter stated that they do not object, in general,
to the concept of coordinating BACM and MACT, discussions
concerning BACM have indicated that numerous additional specialty
coating categories are proposed for regulation.
Two commenters (IV-D-80, IV-D-83) stated their opposition to
the elimination of a formal public comment period by the issuance
of a BACM and not a draft CTG.
Two commenters (IV-D-80, IV-D-83) stated that if regulation
of specialty coatings is to be incorporated into the Aerospace
NESHAP, then the EPA should separately propose such regulation in
the Federal Register as an amendment to the Aerospace NESHAP and
provide opportunity for public comment. Three commenters (IV-D-
29, IV-D-35, IV-D-39) believe that specialty coatings are more
appropriately addressed through the CTG after appropriate public
comment.
Commenter IV-D-83 recommended that the EPA issue a draft CTG
for public comment within the next few weeks. The commenter was
willing to help fast track the CTG through the regulatory process
and the comment period. They felt that a final version could be
ready for issuance in March or April of 1995.
Three commenters (IV-D-ll, IV-D-14, IV-D-42) recommended
that a CTG not be developed for low-usage coatings based on the
minor emissions they contribute.
Commenter IV-D-42 stated that low-usage coatings, such as
adhesives, sealants, and specialty coatings reportedly contribute
less that 6 percent of the total HAP emissions.
Commenter IV-D-14 stated that it would be difficult to
supply a guideline for control of low-usage coatings when the
MACT floor analysis determination was "no control." The
commenter believes that these low-usage coatings will most likely
be contained in a MACT floor of no control.
Commenter IV-D-ll stated that whether or not a coating is
low-usage should not be a basis for it having separate emission
control procedures. The commenter concluded that, in addition to
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the limited usage rates, many of these products have a very low
HAP and VOC content and additional rules would provide only
minimal emission reductions.
Response: In response to section 183(b)(3) of the Act, the
EPA is preparing a CTG for the aerospace industry. Issuance of
this document is expected to occur sometime after the
promulgation of the NESHAP.
The VOC content limits in the CTG for primers, topcoats, and
chemical milling maskants will be the same as those being
promulgated in the final NESHAP. The CTG also addresses numerous
low-usage specialty coatings. The EPA will provide VOC limits
for each of the specialty coatings listed in the CTG.
2.2 FACILITY-WIDE EMISSIONS AVERAGING
Comment -. Commenter IV-D-31 recommended that emissions
averaging not be provided for in this rule. This commenter
stated that this industry in the past has simply not met emission
limitations when permitted to use averaging, and felt that the
proposed limits can be met without averaging. The commenter
stated that, if averaging is retained in the final rule, stricter
emission limitations must apply to those categories in which
averaging is allowed. The commenter believes that daily
demonstrations of compliance are essential, as the EPA has
proposed. The commenter also stated that, if emissions averaging
is retained, the EPA should continue to limit it to averaging
within a single type of material as proposed. They also felt
that averaging across types of products would be illegal under
the Act.
Commenter IV-D-52 stated that their agency has removed
compliance options using emissions averaging from their aerospace
rule and instead, require each individual topcoat and primer to
meet specified VOC limits. The commenter stated that one of the
primary reasons for eliminating the averaging provisions was to
comply with the criteria specified in the EPA's Federal Emissions
Trading Policy (FETP). They requested that the EPA clarify the
applicability of the FETP and its relationship to the proposed
NESHAP.
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The commenter pointed out that the aerospace facilities
within their jurisdiction already comply with the proposed VOC
limits without averaging between coatings. The commenter,
therefore, recommended that the EPA provide State and local
agencies with the option of excluding the emissions averaging
provisions upon delegation, with an up-front determination in the
NESHAP that this option is clearly more stringent, and that no
equivalency determination be required under Subpart E. The
commenter indicated that this was done for the hazardous organic
NESHAP (HON), and should be appropriate for this rule as well.
Eight commenters (IV-D-27, IV-D-29, IV-D-35, IV-D-37, IV-D-
38, IV-D-47, IV-D-48, IV-D-51) urged the EPA to maintain an
emissions averaging option within the Aerospace NESHAP.
Commenter IV-D-27 stated that emissions averaging is a viable
alternative even though additional recordkeeping requirements are
needed. In general, the commenter does not view emissions
averaging as the norm but does consider it a safety net where
relatively low usage applications may require a coating that has
a higher VOC/HAP content than is allowed in the rule. Commenter
IV-D-35 believes that such an averaging option is necessary as a
safety net approach, used to efficiently and effectively maintain
compliance. The commenter also stated that an emissions
averaging scheme should allow for a balancing of high and low-VOC
and/or HAP materials to achieve the same net compliance
requirement under a site-specific or plant-wide averaging scheme.
Commenter IV-D-27 also stated that emissions averaging tends to
encourage industry to test the new low VOC/HAP technologies in
order to have the option of implementing emissions averaging in a
critical situation. Two commenters (IV-D-27, IV-D-29) stated
that it is critical that industry have the flexibility to choose
the most cost effective methods of compliance and recommended
that the EPA expand the averaging approach.
Commenter IV-D-39 stated that, while they support averaging
as a strategy for reducing hazardous air pollutants, they fail to
understand the rationale for denying a source the flexibility to
average a controlled source with an uncontrolled source. The
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commenter also stated that, assuming that averaging would be
between emission points within the same source category, no
reason suggests itself for denying a source the ability to
average between these sources. The commenter pointed out that
methodologies have been developed by the Agency that allow the
source to calculate overall emissions appropriately (e.g., the
draft wood furniture manufacturing NESHAP). The commenter
recommended that the EPA reconsider the provision.
Commenter IV-D-35 stated that application of control to
emissions from compliant or exempt substances, and application of
a control device having overall control efficiency greater than
81 percent is voluntary overcontrol, which creates a potential
credit. The commenter claimed that credits generated by any
process or overcontrol initiative of regulated or unregulated
materials should be available to balance or otherwise offset
other required emission reductions. The commenter provided
equations, supporting data, and a broad based emissions averaging
scheme.
The commenter also stated that failure to provide a workable
emissions averaging system, which accounts for verifiable credits
over a reasonable averaging period, subject to enforceable permit
conditions, is counter to commonly held environmental and
business goals. The commenter, therefore, recommended the
addition of §63.745(d)(3) to read as follows:
"Apply emission controls to compliant processes, generating
an overcontrol credit that can be applied to decrease the
actual emission level from a similar source. Unless item-
by-item correspondence is demonstrated between the
constituents of the overcontrolled emission and of the
emission against which it is to be credited, the credit
available under this option must be negotiated between the
emitting organization and the cognizant regulatory agency
and its designated representative."
Commenter IV-D-35 claimed that the averaging time allowed by
the rule is far too short and does not allow enough flexibility
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for the user in determining compliance and in adjusting workloads
and scheduled activities. The commenter stated that the daily
average specified in the proposed rule is unsatisfactory for the
following reasons: (1) partially used containers may be carried
over from one day to the next; (2) individual jobs may require
more than one day; (3) recordkeeping, processing, and reporting
will be an expensive undertaking; and (4) periods of required
extreme activity (e.g., Desert Storm) can be averaged out. The
commenter believes a minimum 30-day period is necessary for DoD
rework facilities and field operations. The commenter believes
that without a workable emissions averaging scheme, a
disproportionate amount of resources will be dedicated to
reducing emissions from low volume coatings.
Commenter IV-D-29 also requested that the EPA consider
allowing a 30 day averaging period and emissions trading for any
regulated source under the Aerospace NESHAP. The commenter
believes that the value of emissions averaging would be severely
restricted if the industry were restricted to 24-hour averaging.
The commenter stated that aerospace operations are very batch
oriented, that it may take 2 years from start to finish to
produce a large aircraft, that identical parts are not coated on
a daily basis, and that most aircraft lines produce less than 10
aircraft per month. For these reasons, the commenter concluded
that identical parts may be coated only a few times per month
requiring the 30-day period for averaging.
Commenter IV-D-35 claimed that DoD facilities must have
longer averaging times to provide for fluctuations in workload
which can be driven by readiness and mobilization needs which are
beyond the control of individual facilities. The commenter,
therefore, recommended the following revisions:
Change §63.745(d)(2)(i) and §63.749(d)(1) to read as follows:
"Use any combination of primers or topcoats such that the
quarterly volume-weighted average organic HAP and VOC
content of the combination or primers or topcoats complies
with the specified content levels."
Change §63.745(d)(2)(ii) to read as follows:
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"Compliance may be demonstrated by averaging emissions from
both primers and topcoats together for those constituents
for which item-by-item correspondence is demonstrated.
Averaging of non-equivalent emissions requires written
approval of the cognizant regulatory agency or its
designated representative."
The commenter stated that the volatile organic constituents
of most coatings used are generally similar. The commenter
believes that the similarity of constituents provides significant
opportunity for direct (one-for-one) exchange. According to the
commenter, the presence of hazardous materials exhibiting
dissimilar toxicological activity for a material having non-
toxicological characteristics will and should require evaluation
by the Administrator before an arbitrary judgment of
interchangeability is made.
The commenter also stated that given the high cost of
installing control devices, averaging of controlled and
uncontrolled primer and/or topcoats should be allowed, provide
the net weighted emissions does not exceed the average of the
appropriate categores over the averaging period. The commenter,
therefore, recommended that §63.745(d) (2) (iii) be deleted.
Two commenters (IV-D-38, IV-D-47) encouraged the EPA to
include provisions that would provide for compliance with
prescribed HAP emission limits by averaging emissions across
various operations regulated under the rule. The commenters
believe that an emissions averaging provision would provide a
much more reasonable and fair approach to reducing HAP emissions
than a ban on organic HAP emissions from depainting operations.
Four commenters (IV-D-35, IV-D-37, IV-D-48, IV-D-51)
supported an emissions averaging scheme that allows emissions
trading and averaging between NESHAPs. Specifically, three
commenters (IV-D-35, IV-D-37, IV-D-51) conveyed their support for
the emissions averaging proposal submitted by commenter IV-D-48.
Commenter IV-D-48 provided an emissions averaging proposal,
which is very similar to the proposal adopted by the EPA for the
HON on April 22, 1994. The key aspects of the proposal and
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critical policy considerations presented by the commenter are as
follows:
1. Limited banking of credits
2. Intercategory trading and credits for reductions of HAP
not covered by a NESHAP category
3. The value of credits and their life expectancy
4. Interpollutant trading
5. Recordkeeping and reporting
6. The EPA should specifically allow credits for "no
paint" of the aircraft exterior fuselage
7. The proposal compares favorably to the averaging rule
adopted in the HON.
In order to better explain the proposal, the commenter provided
regulatory language as an example of how an aerospace averaging
rule could be written.
The commenter stated that the emissions averaging proposal
provides support for the following important public policy
considerations:
1. Broad-based emissions averaging provides the only means
of advancing the Administrator's goal of advocating
Pollution Prevention policies.
2. Emissions averaging provides the source with the
flexibility to consider a multi-media approach to
meeting the mandated emission standards.
3. Broad-based averaging allows the source to select the
means to achieve the emissions reduction, thereby
achieving the same environmental gains at significantly
reduced costs.
4. Establishing MACT standards with a facility-wide
averaging program could result in a MACT "floor" for
future standards being tighter than would have been the
case if the emission points outside of the already
covered MACT categories would have stayed uncontrolled.
5. A broad averaging scheme may result in the discovery of
emission points within facilities that otherwise might
have been overlooked by EPA and State regulators.
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According to the commenter, the only legal obstacle to the
proposal is whether or not the EPA may define "source" under
section 112(d) to include all HAP emission points at the same
plant site so as to allow emissions averaging plant-wide and
between and among all sources of HAP at the facility. In
considering this issue, the commenter also discussed whether a
broad-based definition of "source" is consistent with the
requirement that all sources must comply with a MACT floor
established pursuant to section 112(d). The commenter also
evaluated whether section 112(d) requires that all emission
points meet the technology-based standard established by the EPA
under sections 112(d)(2) and (3), or is it sufficient that a
source's overall emissions be equal to or less than total HAP
emissions that would have been emitted had all emission points
applied the MACT standard technology. Finally, the commenter
presented an analysis of the policy and regulatory precedent that
has already been established by Congress and the Agency for
emissions averaging programs such as that set forth in the
proposal.
Based on their evaluation, the commenter determined that the
EPA has the legal authority to define "source" under section
112(d) in a manner that would allow facility-wide emissions
averaging within, between, and among all sources of HAP emissions
at a contiguous plant site that is under common ownership or
control. Furthermore, the commenter stated that EPA's Office of
General Counsel issued a legal opinion dated May 14, 1991, which
specifically addressed the issue of the Agency's authority to
broadly define "source" under section 112(d) and concluded that
the Agency could in fact define "source" broadly enough to allow
emissions averaging under section 112(d). In addition, the
commenter noted that recent actions taken by the EPA to propose
and promulgate rules under sections 112(g) and 112 (i) (5) and the
HON NESHAP rule is further evidence of the Agency's recognition
of its legal authority to broadly define "source" such that
emissions averaging is allowed under section 112(d) of the Act.
Commenter IV-D-51 also conveyed their support for the use of
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computer modeling, which would be used as a tool to demonstrate
compliance, in the proposal submitted by commenter IV-D-48. The
commenter believes that the use of emissions averaging and
computer modeling will provide direct benefit to the EPA. They
suggested that the generation of fenceline data by facilities
utilizing computer models will be beneficial to the EPA in the
assessment of "residual risk," which must be accomplished by the
EPA for future rule development.
Commenter IV-D-35 also submitted an equation to be used in
conjunction with the proposal submitted by commenter IV-D-48.
The equation contained equivalency factors that address concerns
by the Natural Resources Defense Counsel (NRDC), which stated
that not all pollutants are equal. The factors adjust for the
differences in pollutants and apply to the trading of emission
credits. Additionally, the commenter suggested that the proposal
submitted by commenter IV-D-48 should be revised by changing the
length of time a credit is available and discounting the credit
depending on the attainment status of a region.
Response: The final rule does not allow averaging across
source categories; therefore, topcoats can only be averaged with
topcoats, primers with primers, etc. The final rule does,
however, allow facilities to use monthly averaging periods
instead of daily averaging. The facilities which choose to use
averaging as a means of demonstrating compliance must submit the
averaging scheme to the permitting authority as part of their
title V permit. In addition, the permitting authority can limit
the time period that may be used for averaging to less than 30
days. In no case may the averaging period be longer than 30
days.
The EPA is currently investigating a number of options with
respect to implementing a broad-based averaging scheme as a
compliance option for the Aerospace NESHAP. The EPA must
determine the compatability of an averaging scheme with other
local, State, and Federal regulations and the enforcability of
such a plan in addition to determining the best way to implement
a plan that produces quantifiable emissions reductions and
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guarantees the public's safety. The EPA will issue a
supplemental proposal to the NESHAP that will solicit public
comments on a plan that the Agency deems to be enforcable,
quantifiable, and guarantees emissions reductions and the
public's safety.
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3.0 APPLICABILITY ISSUES
3.1 CLARIFICATION OF APPLICABILITY
Comment: Commenter IV-D-29 believed that the proposed rule
as drafted could be read to cover non-aerospace activities
conducted at an aerospace facility. The commenter stated that
since the EPA has not gathered information on such activities,
these non-aerospace activities must be excluded from coverage.
The commenter pointed out that, even if these sources are
excluded, the rule will still apply to all aerospace activities,
no matter how small, conducted at a non-aerospace "major source."
According to the commenter, both the Clean Air Act and the
California regulations, on which EPA's "MACT floor" analysis is
heavily based, require the rule to exclude these activities.
Commenter IV-D-35 pointed out that in the preamble to the
proposed rule, the EPA stated that the NESHAP will apply to "each
aerospace manufacturing and rework facility that is a major
source, ..." (59 FR 29221). Two commenters (IV-D-39, IV-D-35)
noted that "aerospace facility" is defined in the preamble as "a
facility that produces in any amount an aerospace vehicle or
component, or a facility that reworks (or repairs) these vehicles
or components." Commenter IV-D-35 also noted that the preamble
goes on to state that "aerospace operations at any major source
that conducts both aerospace and non-aerospace work would be
subject to the proposed standards, regardless of the relative
proportion of aerospace and non-aerospace work at the facility."
The commenters suggested that the entire applicability section
discussion leaves the reader confused as to the EPA's intent with
respect to non-major aerospace facilities.
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Four commenters (IV-D-27, IV-D-29, IV-D-30, IV-D-35) stated
that many sources that would constitute "aerospace facilities"
under the proposed definition manufacture or rework both
aerospace components and non-aerospace components in the same
plant or production area. The non-aerospace components could
include parts for ships, boats, cars, trucks, etc. According to
three of the commenters (IV-D-27, IV-D-29, IV-D-35), these
activities have not been studied by the EPA and present wholly
different regulatory problems from those aerospace activities
that have been studied, and, therefore, should not be covered by
the Aerospace NESHAP. The commenters pointed out that under a
literal reading of the proposed rule, painting, depainting, etc.,
connected with these non-aerospace activities could also be
covered by the Aerospace NESHAP because they take place at a
facility engaged "in part" in the manufacture or rework of
aerospace vehicles or components. The commenters further stated
that since coverage of non-aerospace activities would exceed the
scope of the EPA's statutory authority, and the EPA has not
gathered information on such activities or analyzed the wisdom of
controlling them, they must be excluded from coverage.
Commenter IV-D-49 expressed concern that the scope and
applicability of the regulation is too broadly defined, covering
not only those facilities whose primary mission is to manufacture
or rework aerospace, but also contractors and subcontractors who
perform work on components of aerospace vehicles. The commenter
noted that there are potentially thousands of small businesses
that provide components to the aerospace industry and each may be
subject to the rule if they are major sources of HAP. The
commenter illustrated this with reference to a manufacturer of
fasteners who sells a product to a wholesaler or distributor, who
then in turn sells these products to an aerospace manufacturer
for a component in an aerospace vehicle. The commenter asked
whether the manufacturer of the fasteners would be subject to the
rule, even though the manufacturer may not be aware that their
fasteners are being used in the aerospace industry.
Three commenters (IV-D-30, IV-D-35, IV-D-49) suggested that
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a more reasonable reading of the proposed rule would be that the
stringent NESHAP requirements do not apply to non-major aerospace
activities if they occur on an installation that is a major
source for other than aerospace emissions. Commenter IV-D-30
pointed out that the aerospace rule may be significantly more
stringent than the standards related to the predominant work
performed at the facility and a requirement to meet stringent
standards for a small amount of their total business could
discourage vendors and subcontractors from competing for
aerospace work. Commenter IV-D-35 stated that they would incur
significant costs if the EPA subjects non-major aerospace
activities to the proposed rule. The commenter pointed out that
they conduct operations that involve aircraft at hundreds of
locations throughout the country and that their activities often
involve some form of aerospace work that would be covered in the
NESHAP. According to the commenter, extending the proposed rule
to these low HAP-emitting activities would be tremendously
expensive with minimal benefit to the environment, as these
activities involve low volumes of work.
Commenter IV-D-39 interpreted the proposed standards to mean
that an aerospace facility that manufactures both aerospace and
non-aerospace components would be subject to the NESHAP
provisions, including coating limits. The commenter believes
that this provision should be amended, at least insofar as
coatings applications are concerned, since the coatings used in
the aerospace industry are highly specialized and quite specific
to their different uses. The commenter stated that VOC and HAP
limitations on coating categories (topcoat and primer)
established by the proposed rule are aerospace-specific and
cannot be applied to non-aerospace coating applications that may
be conducted at a major source performing aerospace manufacturing
or rework operations (e.g., electronics manufacturing).
According to the commenter, if the EPA did not intend this result
by this provision, clarifying language is needed.
Two commenters (IV-D-27, IV-D-29) were concerned that the
universe of activities and sources subject to the requirements of
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the Aerospace NESHAP is not precisely defined. The commenters
believe that without precision and clarity as to which sources
and activities are, and are not, covered by the rule, neither
potentially affected facilities nor the EPA itself will be able
to determine whether or not specific activities are subject to
regulation.
Response: Section 112(d)(1) of the 1990 Clean Air Act
Amendments requires the Administrator to "promulgate regulations
establishing emission standards for each category or subcategory
of major sources and area sources of hazardous air pollutants
listed for regulation ..." A major source is one that emits or
has the potential to emit, considering controls, 9.1 Mg/yr (10
tpy) or more of any single HAP or 22.7 Mg/yr (25 tpy) or more of
any combination of HAP. In developing these regulations, the EPA
interprets these HAP emission thresholds to apply to the total
emissions from all activities carried out at a facility.
The Agency is aware that, at many facilities, emitting
operations in more than one processing or product category
(emission source category) are carried out. Clearly, then, any
major source has the potential to be made up of any number of
smaller (non-major) sources. If the major source definition
applied only to the total of operations within a single source
category, HAP emissions at many major source facilities could go
unregulated. This situation would be unacceptable to the Agency.
The approach taken in this rule, and in other NESHAP
regulations, is to determine the total potential HAP emissions
for a contiguous plant site under common control, and make the
major source determination on this basis. Then, the activities
within the plant site are matched to any covered operations in
the NESHAP rules. The provisions of a particular NESHAP are then
applicable to the specific operations within the source category
covered by the NESHAP.
The EPA believes that a manufacturer is aware of the
ultimate application of the parts it produces. Under the
Aerospace NESHAP, any cleaning, application of primer, topcoat,
or chemical milling maskant, or depainting associated with
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aerospace vehicles or components must satisfy the requirements of
this rule. Other, non-aerospace activities need ao_t satisfy
these requirements. However, a facility is not restricted from
extending the practices to other operations where it elects to do
so. For example, it might simplify purchasing, recordkeeping,
employee training, etc, if the same hand-wipe cleaning solvents
and housekeeping measures are used for several or all operations
within a facility. Similarly, certain primers, topcoats, or
chemical milling maskants may find multiple applications across
different source categories.
The Agency did not receive any substantive information on
the nature, number, and locations of non-major aerospace
facilities in response to its request for comment in the proposal
preamble. Since data are not presently available to serve as a
basis for regulation of these smaller sources, the EPA has
decided to not extend the requirements of the final rule to non-
major sources.
Comment: Commenter IV-D-5 stated that if the statement is
correct that the proposed rule "refers to all facilities that
manufacture aerospace vehicles or components and all facilities
that rework (including repair) these aerospace vehicles or
components," the proposed rule is seriously flawed in that the
number of facilities is grossly underestimated. The commenter
also claimed that the EPA does not have accurate information on
the number of aerospace facilities if it intends to include the
entire aerospace industry.
Response: The EPA's comment in the proposal preamble was
not intended to indicate that the Agency's estimate of facilities
represented all facilities involved in aerospace work. At 59
FR29217 (column 2.) , it was stated that, "for the purposes of the
proposed rule, aerospace industries refers to all facilities that
manufacture ...and ...that rework ...aerospace vehicles or
components." Thus, the commenter appears to have been confused
by the distinction between the portion of the industry that was
analyzed and the regulatory coverage of the proposed rule.
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Comment: Commenter IV-D-10 requested that the regulation be
clarified as to whether field operations are to be covered. For
example, if a subcontractor performs work at an Air Force base,
is the subcontractor or the Air Force responsible to see that the
requirements of the regulation are fulfilled?
Response: The final rule clearly states that the owner or
operator of an affected source or operation is responsible for
meeting the requirements of the rule. This would apply even for
the case of a contractor who performs work within the confines of
an affected plant site. In individual cases, however, the
enforcing authority would be free to exercise discretion in
determining the responsible party. In other words, either or
both parties could be subject to enforcement action if violations
of this NESHAP were discovered.
Comment: Three commenters (IV-D-27, IV-D-29, IV-D-35)
recommended similar alternative definitions of "affected source,"
one of which reads as follows:
"Affected Sources. The affected sources to which the
provisions of this subpart apply are specified in §63.741
(c)(1) through (6). The activities subject to this subpart
are limited to the manufacture or rework of aerospace
vehicles or components as defined in this subpart. Section
63.741 (c) (1) through (6) are not applicable to non-
aerospace activities."
Response: Since this change clarifies the intent of the
rule, the final rule has been revised to incorporate the
substance of this new language.
Comment: Commenter IV-D-30 stated that in numerous
discussions with the EPA, it has been presumed that manufacturing
and rework operations related to space activities would be
covered under the Aerospace NESHAP. The commenter believes that
the standard industrial code (SIC) code listing is not specific
with regard to space activities, particularly in the area of
rework. The commenter suggested that the rule specifically state
that ground support equipment, tooling, and other non-flight
hardware are not intended to be regulated under the Aerospace
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NESHAP. The corranenter further stated that it is their
understanding that satellites and similar vehicles are intended
to be exempt under this rule. The commenter suggested that the
EPA clarify the applicability of this regulation to space
operations.
Response: The SIC codes referred to at proposal were
provided to give a general idea of the industrial categories
affected. The rule, however, has not been structured to apply to
any sectors on the basis of SIC codes.
The applicability of the rule has been modified based on
comments. The final rule applies to facilities that manufacture
or rework aerospace vehicles and components (§63.741(a)). The
definition of "aerospace vehicle or component" now refers to
"integral equipment" which includes tooling and other types of
non-flight hardware (see Section 4.2).
The final rule does not apply to operations involving space
vehicles (§63.741(f)). The exclusion is intended to specifically
include all of the systems and components directly associated
with the Space Shuttle, including the Shuttle vehicle itself. A
definition for "space vehicle" has been added to the rule
(Section 4.22).
Comment: Commenter IV-D-28 believes that the extension of
the aerospace MACT standard to operations outside the SIC codes
for aerospace industries will result in the imposition of
inappropriate requirements on too broad a segment of the
manufacturing sector. The commenter pointed out that this is
particularly true for facilities involved in the manufacture,
rework, reconditioning, or repair of aircraft transparencies.
Response: As mentioned above, the applicability of the
final rule is not structured in terms of SIC codes, but in terms
of specific HAP-emitting activities performed in manufacturing
aerospace vehicles and components.
This commenter (who manufactures, reconditions, and repairs
glass transparencies (windshields) for aircraft) pointed out
that, given the stringent requirements of the glass cleaning
solvents that they not affect the lamination of interlayer
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material to glass, there are no alternatives presently available
for the solvents being used. The EPA considered these comments,
and has added an exemption for glass substrates to the cleaning
solvent requirements in §63.744(e)(10).
Comment: Two commenters (IV-D-29, IV-D-32) stated that it
is their understanding that the EPA intends to control electronic
manufacturing and rework by other developing NESHAP. The
commenters, therefore, suggested that the EPA make this clear in
the rule and exclude such activities from Aerospace NESHAP
coverage. They indicated that, under a literal reading of the
proposed rule, much electronic production would be subject to
this NESHAP. One of the commenters stated that electronic
components destined for aerospace vehicle use often receive a
"conformal" coating, a thick coating designed for protection. In
addition, the individual components or electronic subassemblies
are subject to cleaning operations. The commenter requested that
the EPA clarify that the manufacturing and rework of such
electronic parts, assemblies, boxes, wiring, harnesses, and
connectors are not subject to the Aerospace NESHAP; however, if
topcoated or cleaned as assemblies after initial installation in
the aerospace vehicle or component, these latter operations would
be subject to the Aerospace NESHAP.
Response: The EPA agrees that the manufacture and rework of
electronic parts and assemblies constitutes a separate source
category and that this equipment should not be covered by this
NESHAP unless it is an installed part of the aerospace vehicle or
component. The proposed rule, in §63.744 (e) (4), exempted the
cleaning of electronics and assemblies containing electronics.
Final §63.741(f) indicates that the NESHAP does not regulate
"electronic parts and assemblies (except for cleaning and
topcoating of completed assemblies)." By this new provision, all
of the operations on electronic parts and partially assembled
components will be exempt. The NESHAP regulates the cleaning and
topcoating of completed electronic assemblies when those
assemblies are permanently installed in the aircraft or when
those assemblies receive the same cleaning and topcoating
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operations as other parts of the aircraft.
Comment: Commenter IV-D-35 stated that the Aerospace NESHAP
is the appropriate regulation to address composite parts or
components, but that it is impractical for the industry to comply
with separate standards where composite parts and metal parts are
joined into integral structures and processed as a single unit.
The commenter, therefore, recommended that the following be added
to the Process Descriptions and Control Technologies section of
the proposal preamble:
"Composite parts or components which become part of the
aerospace vehicle or component, as well as the portion of
composite lay-up tooling that comes in contact with the part
or component being manufactured, are intended to be covered
by the Aerospace NESHAP and not to be covered by other
standards such as the Plastic Parts rule."
Commenter IV-D-29 mentioned a reference in the proposal
preamble to non-coating operations that are not included in the
rule because of their environmental insignificance. These
include chemical milling, metal finishing, metal
electrodeposition, composite processing, and wastewater
operations. While the commenter agrees with the EPA that
chemical milling, metal finishing, and wastewater operations
should be excluded, the commenter believes that certain aspects
of composite processing and paint electrodeposition (which are
actually related to "coating") should be included in this
Aerospace NESHAP.
With regard to the process of "electrodeposition," the
commenter stated that the EPA indicates in the proposal preamble
that this term applies to metal plating, when in fact the term
has a broader meaning. According to the commenter,
electrodeposition of paint is a fully developed technology in
non-aerospace industries and it is well known to have very high
transfer efficiencies (>95 percent). The commenter, therefore,
suggested that electrodeposition, as it relates to paint, be
added to the list of application techniques that may be used.
The commenter, however, supported exclusion of electrodeposition
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as it relates to metal plating from the Aerospace NESHAP.
Response: The EPA agrees that composite parts or components
(hardened resins containing reinforcing materials) should be
subject to the cleaning and coating standards of this NESHAP when
the composites are to be assembled as an integral part of an
aerospace vehicle of component. These requirements would also
extend to "integral equipment" that may include or consist of
composite materials, in accordance with the revised definition of
"aerospace vehicle or component" (see Section 4.2).
The EPA also agrees that electrodeposition dip coating of
paint (as opposed to plating with metal) is a valid, highly
efficient application technology. The final rule, in
§63.745(f) (1) (vi), includes electrodeposition (dip) coating as
one of the acceptable application techniques for primers and
topcoats.
Comment: Commenter IV-D-49 requested clarification from the
EPA regarding whether weapons systems are considered aerospace
components and therefore subject to the proposed rule.
Response: The EPA considers weapons systems that attach to,
or install in, any aerospace vehicle designed to operate within
the earth's atmosphere to be aerospace components and thus
subject to the requirements of the final rule. Of course, the
low coating usage, specialty coating, and other exemptions
provided in the rule will apply to these systems in the same way
they apply to aerospace vehicles and components generally.
Comment: Commenter IV-D-27 recommended clarification to
§63.741(a) to ensure the Aerospace NESHAP is only applicable to
major sources as defined in Title III of the CAA of 1990. The
commenter recommended that the phrase "either in part or in
whole" in §63.741(a) be deleted to eliminate potential confusion
regarding applicability. The commenter believes that the Title
III definition of a major source should be sufficient to
determine when NESHAP requirements apply. For these reasons, the
commenter recommended that §63.741(a) be revised to read as
follows:
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(a) This subpart applies to facilities that are engaged in
the manufacture or rework of commercial, civil, or military
aerospace vehicles or components and that are major sources as
defined in §63.2.
3.2 COVERAGE OF NON-MAJOR SOURCES
Comment: Numerous commenters (IV-D-3, IV-D-7, IV-D-11,
IV-D-12, IV-D-23, IV-D-29, IV-D-30, IV-D-33, IV-D-35, IV-D-38,
IV-D-42, IV-D-43, IV-D-45, IV-D-47, IV-D-49, IV-D-50, IV-D-57)
stated that they are opposed to the application of the proposed
NESHAP to non-major sources. Seven commenters (IV-D-7, iv-D-li,
IV-D-14, IV-D-35, IV-D-38, IV-D-47, IV-D-57) stated that if the
requirements of the proposed rule were imposed, the economic
effect on non-major sources would be detrimental to the survival
of some businesses or at least extremely burdensome.
Two commenters (IV-D-29, IV-D-35) noted that since the EPA
has discretion under the Clean Air Act on whether and how to
regulate non-major sources under section 112, any extension of
regulation to such sources would have to be based on a deliberate
and considered decision that such an extension represents wise
policy. According to commenter IV-D-29, no grounds for such a
decision are set out in the proposal. On the contrary, the
overall structure of the proposed rule and the preamble
discussion make clear that the very small emission reductions to
be expected from such an extension would be far outweighed by the
costs of testing, recordkeeping, and reporting that would be
imposed both on regulatory agencies and on affected sources by
the rule. The commenter proposed that even without regulation by
the EPA, emission reductions at many such sources can be expected
as a result of State action, voluntary emission reduction
measures, or imposition of new contract requirements reflecting
Aerospace NESHAP requirements on small sources that are
subcontractors to regulated sources.
Commenter IV-D-29 stated that since no MACT floor has been
established for non-major sources, and since the EPA has not even
attempted to conduct a "beyond the floor" analysis that would
justify regulating them, they cannot legally be covered by the
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Aerospace NESHAP. The commenter also pointed out that the four
California rules, heavily relied on by the EPA to establish the
MACT floor, contain a de minimis exclusion to avoid regulating
small sources that may undertake some aerospace work at their
primarily non-aerospace facility.
Commenter IV-D-11 believes that one significant economic
effect of requiring non-major sources to comply with the proposed
rule would be to drive their customers to do business with
subcontractors that have facilities outside the territorial
boundaries of the U.S. Commenter IV-D-57 stated that it is
unrealistic to hold a very small firm to a MACT standard that may
be the result of a million-dollar investment at a large OEM
plant. According to this commenter, there are significant
differences among small and large firms in their ability to raise
capital, in addition to a great disparity in the ability of small
companies to train workers and implement new technologies.
Commenter IV-D-7 stated that application of this proposal to
non-major sources would be redundant and over regulatory since
their firm is already closely monitored by the State control
agency. Commenter IV-D-50 pointed out that some of their area
source facilities are already subject to regulation under State
laws with respect to their coating and solvent cleaning
operations. Commenter IV-D-57 stated that small firms are
already subject to existing regulations for cleaning operations
and waste handling and storage, as well as general requirements
for clean air, stormwater, and so on.
Commenter IV-D-57 was concerned that computing potential
emissions on a 24 hour/day, 365 day/year basis could result in
grossly unrealistic emissions data for many small firms. This
commenter also pointed out that most of these smaller firms work
a total of 40 to 50 hours per week and are precluded from working
a second or third shift by constraints of skilled labor
availability or by lack of sufficient customer demand.
Three commenters (IV-D-23, IV-D-42, IV-D-43) recommended
that State and local agencies retain the authority to regulate
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non-major sources.
Commenter IV-D-3 stated that many small companies are
already regulated under existing EPA-delegated emission permits
and that regulations fall much harder on small companies. The
commenter claimed that the regulation is extensive and
burdensome, far out of proportion to the small amount of
emissions generated.
Commenter IV-D-12 stated that locating area sources in this
source category could be very difficult, since most of them will
be in non-aerospace SIC codes. The commenter, therefore,
recommended that regulation of area sources be considered for
inclusion in the Urban Area Source National Strategy that is
required under section 112(k) of the Act.
Commenter IV-D-11 stated that consideration should be given
to the fact that non-major sources do not individually contribute
the same quantity of emissions as major sources and to the
negative economic effect on these sources. The commenter
suggested, therefore, that area source controls should be defined
as a separate, generally achievable control technology as
Congress intended. Two commenters (IV-D-23, IV-D-45) stated that
due to the extensive reporting and recordkeeping requirements of
the proposal, area sources should not be included in this MACT
standard. The commenter suggested, however, that the EPA
consider establishing a separate source category and adopting a
MACT standard to address smaller facilities that do limited
amounts of aerospace work.
Commenter IV-D-45 noted that most of their facilities are
non-major sources that typically perform a wide variety of tasks
related to the cleaning, coating, and removal of coatings
necessary to the aerospace subsystems they produce, and therefore
they would be subject to the same reporting protocols, albeit for
smaller quantities, as large facilities. The commenter further
stated that the reporting requirements of this rule, which are a
tremendous burden to large facilities, would be crippling to
small facilities. The commenter believes sufficient reductions
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at non-major HAP source facilities will be seen from alternate
materials specified by the customers; i.e., the major aerospace
sources, and from application of the control technologies
specified in the control technology guidance in nonattainment
areas.
Commenter IV-D-30 does not believe that the rule should
apply to operations that are not considered major sources of HAP
since emissions reductions would, presumably, be minimal.
Commenter IV-D-35 believes that the application of the aerospace
NESHAP to non-major sources would severely impact many small
operations without producing significant environmental benefits.
Commenter IV-D-50 pointed out that the majority of their
facilities are well below the threshold major source trigger
limits. The commenter claimed that any benefit of imposing the
proposed requirements to reduce HAP or VOC emissions would be
minimal.
Commenter IV-D-49 recommended that the proposed rule apply
only to aerospace operations that cause significant emissions.
The commenter stated that significant emissions could be defined
as amounts which cause the source to be a major source by itself
or perhaps at some lesser quantity as determined by the EPA. The
commenter concluded that a de minimis emission level regarding
applicability is needed to prevent the use of costly MACT on
relatively insignificant emission units. Commenter IV-D-35 also
recommended a de minimis level of activity exemption, pointing
out that non-major aerospace sources will not be completely
unregulated or unaffected by the proposed NESHAP. The commenter
stated that many are already subject to State regulations for
controlling HAP emissions, and have pollution prevention
initiatives underway. The commenter noted that the impact on the
Department of Defense (DoD) would be particularly significant.
The commenter, therefore, recommended that the EPA not regulate
non-major aerospace sources at this time. The commenter
recommended that the EPA separately and methodically evaluate the
costs and benefits of subjecting non-major aerospace sources,
especially those associated with the military, to the proposed
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NESHAP.
Commenter IV-D-14 stated that at a minimum all non-major
sources should submit an operation and maintenance plan, from
which the general provisions for all facilities can be
determined. The commenter believes that something similar to
leak checking, etc. can be applied to all facilities. According
to the commenter, additional requirements or controls under this
NESHAP should be required for the larger non-major sources.
Response: The EPA requested comment in the proposal
preamble on whether non-major sources should be subject to all of
some of the requirements of this NESHAP. This request was made
in order to expand the Agency's data base on the likely impacts
on smaller operations.
Following review of these comments as well as the existing
data base, the Agency had decided that, due to the small amount
of data and information available to assess the effects of
applying full MACT requirements to small sources, non-major
sources will not be included for regulation under the final rule.
The EPA will continue to investigate whether separate, less
stringent standards should be applied to these sources as a
separate source category. State and local regulatory authorities
still have the discretion to control HAP emissions from these
sources in their jurisdictions under their own air toxics
programs.
Comment: Commenter IV-D-33 stated that area sources could
be a significant source of HAP; however, if area sources are
included in the Aerospace NESHAP, they should be exempt from
title V permitting. The commenter offered to work with the EPA
to identify aerospace area sources and develop standards where
appropriate.
Response: The EPA appreciates this offer of cooperation.
Comment: Commenter IV-D-38 noted that the proposed rule
would prohibit methylene chloride in depainting operations based
on the availability of media blasting techniques for military
aircraft and the use of non-HAP chemical strippers and polishing
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techniques in large commercial aircraft. The commenter pointed
out that the record for the rulemaking, however, contains little
or no information on the application of these techniques to
general aviation typically maintained at small to medium size
rework facilities, which likely would not qualify as major
sources. According to the commenter, the lack of supporting data
on the application of alternative depainting techniques for
general aviation is of concern because of the suggestion in the
Federal Register that the Agency is considering extension of some
of the standard's requirements to area sources. The commenter
does not believe that the Agency has collected sufficient data to
support imposing the depainting provisions on area sources.
The commenter estimated that some 2,000 airplanes operated
by regional (commuter) airlines, and several thousand private
aircraft, are maintained with HAP strippers. These aircraft
present a unique challenge for non-HAP stripping techniques
because a majority are thin-skinned and most are painted. The
commenter maintained that existing blasting technologies and
reduced painting are not likely to be maintenance options.
The commenter remarked that commuter and private aircraft
also are unique in that they are maintained at small rework
facilities with limited ability to purchase alternative
technologies or to devote significant research and development
efforts to testing non-HAP techniques. The commenter noted that
the Paint Remover Manufacturers Association (PRMA) has estimated
that facilities maintaining general aviation may total as many as
3,000, and that 40 to 50 percent of these perform depainting.
The commenter concluded that any extension of the depainting
provisions to these facilities would have a substantial economic
impact.
The commenter was also concerned about the potential impact
the current depainting proposal could have on larger area sources
using HAP strippers. The commenter is aware of several
facilities maintaining general aviation that currently fall
slightly below the 10 ton per year threshold for their depainting
operation. The commenter believes that the standard, as
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currently proposed, could limit the ability of these facilities
to expand their depainting operations.
The commenter's concern about larger area sources was
heightened by an uncertainty about the EPA's definition of a
source's "potential to emit." The commenter encouraged the
Agency to evaluate the potential that area sources may be caught
under the Aerospace NESHAP because of an "arbitrary"
interpretation of their potential to emit HAP.
Commenter IV-D-13 stated that compliance with the depainting
requirements would most likely result in significant increases in
other environmental pollution due to several factors:
• General aviation facilities currently complying with
the EPA, Federal, and local air and water pollution
requirements would be removed from the marketplace due
to the inability to remove paint from these aircraft
because of manufacturer and FAA requirements.
• A significant, currently-controlled portion of the
general aviation industry's aircraft would be removed
from EPA visibility.
• General aviation aircraft would continue to be
refurbished by a greater number of smaller operations
that do not fall under the restrictions of this
proposal nor have the financial or enforcement means to
comply with even the current EPA suggested
requirements.
The commenter requested that the general aviation industry
be specifically excluded from the rulemaking efforts. The
commenter concluded that no overall reduction in HAP would occur
as it relates to general aviation aircraft and, in fact, an
overall negative impact on the EPA's goal for improving air and
water quality will occur.
Commenter IV-D-47 did not support application of the
depainting provisions to smaller, area sources because the
commenter believes those provisions contain many defects. The
commenter suggested that the exorbitant costs of media blasting,
and the problems with the effectiveness of both media blasting
3-17
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and non-HAP strippers would only be exacerbated for smaller
entities that have more specialized operations and less financial
flexibility. According to the cornmenter, even if the spot
stripping exemption were expanded, these entities would likely
find it very difficult to comply with the proposed depainting
requirements, as well as some of the other fairly burdensome
requirements for control technologies and recordkeeping. The
commenter also claimed that it would be unwise to impose the
burden of compliance on area sources in the absence of any
evidence that the quantity and nature of uncontrolled HAP
emissions from these smaller sources have any real adverse impact
on health or the environment.
Commenter IV-D-52 stated that, in their AQMD, a number of
facilities with relatively low HAP emissions are engaged in
aerospace component manufacturing and that some of them are
subcontractors that work directly for the OEM or rework
facilities, or indirectly through first line subcontractors. The
commenter claimed that, because these sources generally have no
well-defined maximum capacity, and because they lack federally
enforceable HAP limits, they could be considered major sources
based on their potential to emit (PTE).
The commenter indicated that some of the smaller facilities
in their AQMD that engage in aerospace component manufacturing or
rework will avoid NESHAP applicability by receiving Synthetic
Area Source permits. The commenter believes that is an
appropriate mechanism for facilities with HAP emissions that
approach the major source thresholds; however, another mechanism
is needed for the more numerous facilities that have very low HAP
emissions. The commenter pointed out that several other recently
proposed NESHAP have specifically defined applicability in terms
of actual annual materials throughput. According to the
commenter, if this type of approach is impractical for this rule,
a more general "prohibitory rule" may be adequate. The commenter
recommended that the EPA provide a simple and straightforward
mechanism to limit PTE to keep this (and other major source
rules) from applying to sources with relatively low HAP
3-18
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emissions.
Commenter IV-D-22 expressed concern that many of the large
aerospace firms that clearly fall into the definition of a major
source will offload many of their operations to smaller aerospace
subcontractors that are not defined as major sources. According
to the commenter, if the prime contractors offload to many
subcontractors, no individual subcontractor will be reclassified
as a major source and the sources will be uncontrolled. The
commenter stated that offloading work is a current problem and
that it is likely to be exacerbated by the proposed rule due to
cutbacks in the defense industry. The commenter was also
concerned that workers in the subcontractor firms will be exposed
to higher levels of hazardous chemicals and that emissions of HAP
and VOC from these firms will increase substantially. The
commenter recommended that the regulation apply to all sources
since all aerospace subcontractors perform the same type of
operations as major sources. The commenter noted that
subcontractors, in general, believe that they must do exactly as
the primes require or they will lose business and, in light of
defense cutbacks, this attitude will probably become even more
the norm in the future.
Commenter IV-D-31 stated that they believe that, because
this is an industry with substantial amounts of subcontracting
and one that is undergoing great changes, area sources should be
regulated. Otherwise, according to the commenter, the rules will
provide an incentive to use subcontracting as a means of escaping
emissions control.
Commenter IV-D-48 recommended that, since the standards are
primarily work practices, the Agency should include area sources
in the rule.
Response: The EPA agrees with the first commenter
concerning the application of the depainting requirements to
smaller general aviation rework facilities. For this reason,
such facilities will not be covered under the final rule.
The issue of the use of methylene chloride in depainting
operations is addressed in Section 7.3.
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The concept of "potential to emit" (PTE) is integral to the
definition of "major source" in section 112(a)(1) of the Act.
For this reason, application of PTE in the determination of major
source status should not lead to misattribution of status for any
source.
While the issue of offloading work in order to avoid
regulatory coverage is of some concern, the Agency is not
convinced that a significant number of facilities would be
willing or able to reduce their own production levels (much less
their production capacity) for this purpose.
3.3 REGULATORY EXEMPTIONS
Comment: Commenter IV-D-29 stated that there are many
small-scale or relatively small-scale activities in the industry
that are inappropriate for MACT control. The commenter stated
that some expansion of the list of excluded activities is needed
to fully reflect the range of small-scale activities that the
industry does not now control and cannot practicably control.
The commenter suggested that the EPA provide new or expanded
exclusions for uses involving specialty coatings, adhesives,
adhesive bonding primers, or sealants; and for certain chemical
milling, metal finishing, wastewater operations, and certain
aspects of composite processing, metal electrodeposition, and
other non-coating operations (that will be covered by future
NESHAP). The commenter suggested that all research and
development (R&D), quality control and production testing, and
laboratory testing activities be exempt from all requirements of
the rule, noting that these activities are already excluded from
the proposed cleaning operations requirements.
The commenter believes it is unreasonable to constrain
development work by mandating the use of controlled coatings and
application techniques. Furthermore, the commenter stated, it is
economically burdensome and unreasonable to mandate emission
controls for such small-scale and rapidly varying activities.
According to the commenter, imposing the rule's regulatory
requirements on these activities will adversely impact research
efforts while providing no measurable benefit to protection of
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public health and the environment.
A second commenter (IV-D-49) stated that a similar exemption
is appropriate for R&D activities related to primer and topcoat
applications, as well as chemical milling and masking operations.
This commenter also maintained that it is difficult to
economically justify mandated emission controls for such small-
scale activities.
Two commenters (IV-D-29, IV-D-35) stated that, in excluding
an activity from the rule, the EPA must make clear that its
decision rests on an informed determination that MACT regulation
is not required. As a result, modifications in such activities
will not trigger section 112(g) application. The commenters
offered the following regulatory language in order to make clear
the section 112(g) status of the exempted operations:
"§63.74l(f) This Subpart does not contain control
requirements for uses of specialty coatings, adhesives,
adhesives, adhesive bonding primers, or sealants at
aerospace facilities. Nor does it regulate research and
development, quality control and production testing, and
laboratory testing activities, chemical milling, metal
finishing, electrodeposition (except for electrodeposition
of paints), composite processing (except for cleaning and
coating of composite parts or components that become part of
an aerospace vehicle or component as well as composite
tooling that comes in contact with such composite parts or
components prior to cure), electronics assembly (except for
cleaning and topcoating of completed assemblies), and
wastewater operations at aerospace facilities. Additional
specific exemptions from regulatory coverage are set forth
in §63.741{e) , .744(6), .745(a)(l), (c)(3), (e)(3), (f) (5) .
and ,746(a)(l), (b)(3), (c). During the establishment of
this subpart EPA affirmatively decided not to establish
control requirements for these exemptions from specific
requirements. Accordingly, changes in these uses and
operations and in exempted activities do not trigger
regulation under §112(g)."
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Response: The EPA agrees that such a rule clarification
would be beneficial, and has added to the final rule similar
language to that suggested by the cornmenters.
3.4 SOURCE PERMITTING
Comment: Two commenters (IV-D-29, IV-D-35) stated that
proposed §63.741(d) unnecessarily duplicates the Clean Air Act
title V provisions requiring a major source to obtain a permit.
The cornmenters claimed that since the industry is already
required to obtain permits by statute, there is no need to
include such a provision within the Aerospace NESHAP.
Response: The title v operating permit programs developed
by the States must be approved by the Administrator on an
individual basis. At this time, very few programs have been
fully approved. Therefore, the Agency finds it necessary to
require that an operating permit be submitted under this NESHAP
in accordance with existing part 70 and State requirements. At
the discretion of the permitting authority, existing permits
prepared under a title V program or other programs may be wholly
or partially used to satisfy the permit provisions of the final
rule.
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4.0 DEFINITIONS
Several commenters suggested changes to the definitions of
terms provided in proposed §63.742. These suggested additions
and deletions are indicated by underlining and text strikeouts,
respectively.
4.1 AEROSPACE FACILITY
Comment: Commenter IV-D-27 recommended the following
revision to the definition of aerospace facility:
"Aerospace facility means any facility with a primary SIC
code of 3720. 3721. 3724. 3728. 3761. 3764. 3769. or 4851
and that produces, reworks, or repairs i-n any amount any
commercial, civil, or military aerospace vehicles or
components.."
The commenter believes that the reference to "in any amount"
is problematic for several reasons. First, many aerospace
facilities manufacture or rework both aerospace and non-aerospace
components in the same plant or production area. The commenter
stated that these activities have not been studied by the EPA and
present different regulatory problems from those aerospace
activities that have been studied and, therefore, should not be
covered by the Aerospace NESHAP. This commenter and one other
(IV-D-45) pointed out that aerospace work may comprise only a
minor part of a facility's total operations, and felt that such
11 de minimis" aerospace operations should be excluded from the
scope of this NESHAP.
The commenter also pointed out that if a facility becomes
subject to another source category NESHAP, the requirements may
be conflicting for the same operation. Implementation of the
NESHAP may be quite costly with significant administrative
4-1
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requirements, and companies whose main economic activities (>50
percent) fall under a different SIC code should not be subject to
these requirements.
Response: As discussed in Section 3.1, the EPA does not
wish to structure this NESHAP specifically in terms of SIC codes,
due to the incomplete match between these codes and the affected
aerospace operations. Non-aerospace operations will not be
covered by this NESHAP, even when they occur in the same major
source facility as covered operations. Therefore, the suggested
changes have not been incorporated into this definition.
4.2 AEROSPACE VEHICLE OR COMPONENT
Comment: Commenter IV-D-27 recommended the following
revised definition for "aerospace vehicle or component":
"Aerospace vehicle or component means any fabricated part,
processed part, assembly of parts, or completed unit, with
the exception of electronic components, of any aircraft
including but not limited to airplanes, helicopters,
missiles, rockets, and space vehicles."
The commenter suggested that this phrase be added to the
definition because, according to the commenter, electrical
components or assemblies may at times become part of a larger
assembly such as a missile or avionic system. Material volumes
in these activities are typically extremely low and, therefore,
not significant contributors to overall emissions, and these
types of components or assemblies are scheduled for control under
a separate NESHAP where, collectively, their emissions could make
a significant contribution to air emissions.
Commenter IV-D-lO felt that the EPA should clarify the
definition of a "component" for the applicability of the NESHAP.
The commenter stated that this definition and the reference
discussion suggest, but do not state, that the manufacturers of
electronic controls, communications, and radar equipment may not
be intended to be covered by this NESHAP. The commenter pointed
out that manufacturers of electronic equipment refer to miniature
electronic parts as "components." Therefore, the commenter
suggested that the regulation should distinguish at what point in
4-2
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the manufacturing process an electronic assembly becomes an
aerospace component for coverage in the rule. The commenter
concluded by noting that, if it is not the intent of this rule to
cover the manufacture of electronic equipment for the aerospace
industry, then the definition of an aerospace component should be
revised to reflect this.
Commenter IV-D-30 recommended expanding the definition of
"aerospace vehicle or component" to read as follows:
"Aerospace vehicle or component means any fabricated part,
assembly of parts, or completed unit of any aircraft
including but not limited to airplanes, helicopters,
missiles, rockets, and space vehicles. Integral equipment
such as models, mockups, prototypes, molds, jigs, tooling,
hardware jackets, and test coupons are considered aerospace
components."
Commenter IV-D-29 stated that the proposed definition is too
broad, covering every component of an aerospace vehicle including
components such as microwave ovens and telephones for airliner
cabins, that have nothing intrinsically "aerospace" about them
and have not been studied by the EPA in preparing this rule.
Response: As discussed in Section 3.1, this NESHAP is not
intended to cover uninstalled electronic components. The final
rule specifically states in §63.741(f) that electronic parts and
assemblies are not covered by the NESHAP. In addition, the EPA
has added the revision suggested by commenter IV-D-30. This
revision clarifies the intent of the EPA to include integral
equipment such as models, mockups, etc. in the definition of
aerospace vehicle or component.
4.3 CHEMICAL MILLING MASKANT
Comment: Commenter IV-D-29 stated that the term "chemical
milling maskant" should be revised as follows to provide for
consistent usage of the term "chemical milling" throughout the
rule:
"Chemical milling maskant means a coating that is applied
directly to aluminum components to protect surface areas
when chemically chemical milling the component with a Type
4-3
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II etchant. This does not include bonding maskants. line
sealers, and critical use apd seal coat maskants."
Response: The EPA accepts this revision because it adds
clarification to the definition. The EPA issued a request for
information under section 114 of the Act to several facilities on
June 7, 1995. The letter requested information on the types and
volumes of maskants used and the composition of the etchants used
with the maskants. Based on the information received from the
section 114 information requests, the EPA may issue a
supplemental proposal to include additional maskant categories in
the NESHAP. Maskants not covered by the NESHAP will be addressed
in the Aerospace CTG.
4.4 CHEMICAL MILLING MASKANT APPLICATION OPERATION
Comment: Commenter IV-D-29 stated that "Type II etchants"
technically refers to a class of aluminum etching solutions and
that these etchants are not used to apply chemical milling
maskants. The commenter suggested a change to the proposed
definition of "chemical milling maskant application operation"
they felt would correct this error, and would broaden coverage
from dip or spray applications, to brush or roll applications,
and to applications of other chemical milling maskants. The
commenter recommended the following revised definition:
"Chemical milling maskant application operation means the
use—erf—spray—equipment—or a dip—tank—in which Type—tJ-
"c^"Ciic*.ll t S cl!T€t UD&CL t.O it^O-*- V <5. OilfelVli. O&.L DAI _L _L iri^ m&£,K.
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non-HAP containing materials in this standard. Therefore, the
definition of cleaning solvent must be changed to regulate only
HAP-containing material.
In addition, the commenter proposed to exclude from the
definition liquid materials reported to contain HAP in
concentrations at or below the OSHA threshold concentration set
forth at 29 CFR §1910.1200(g). According to the commenter, a
liquid material containing trace HAP concentrations does not have
the potential to emit HAP in sufficient quantities to result in
significant exposure and, therefore, poses trivial risk to public
health and the environment.
According to the commenter, the definition of cleaning
solvent should be changed as follows to make the definition
consistent with language in §63.744 and throughout the subpart:
"Cleaning solvent means any a liquid material containing., any
HAP reported as exceeding the OSHA de minimis threshold
concentration as defined by 29 CFR S1910.1200ig) and used
for hand-wipe, spray gun, or coating line flush cleaning."
Two commenters (IV-D-27, IV-D-35) recommended the following
revision to make the definition consistent with §63.744 and the
rest of subpart GG:
"Cleaning solvent means tsny a. liquid material used for hand-
wipe, spray gun, or coating line flush cleaning."
Response; The EPA does not wish to include reference to HAP
content in the general definition for "cleaning solvent." The
final rule specifies in §63.741 (f) that coatings and cleaning
solvents containing HAP or VOC at a concentration less than 0.1%
for carcinogens or 1.0% for noncarcinogens, as determined from
manufacturer's representations, are not covered. This broad
exemption excludes water and many other cleaning solutions from
the standard. The cleaning solvent composition requirements are
specified in §63.744(b).
The EPA agrees with the change from "coating line" to
"flush" cleaning in order to increase consistency. Therefore,
the change suggested by the latter commenters has been
incorporated.
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4.6 COATING
Comment: Commenter IV-D-29 stated that "coating" refers to
the material that produces a film on a surface (and not the film
itself). The commenter believes that the following change will
make the definition consistent with the language in the proposal
preamble:
"Coating means a pi'ot&cLivi or decorativefilm—applied to
the surface of an aerospace component: or vehicle material
that is applied to the surface of an aerospace component or
vehicle to form a decorative or functional solid film."
Response: In this regulation, the term "coating" is used to
refer to coating materials in both their liquid and subsequently
solid state. Topcoats, primers, and chemical milling maskants
are defined as coatings in the context of the bulk liquid
materials being applied which are still capable of emitting VOC
and organic HAP. The term "depainting," on the other hand,
refers to removal of a coating that is in the form of a solid dry
film. Depainting emissions would consist of inorganic HAP
particulate coating material when dry media blast processes are
used. Therefore, while the commenter's point is valid, the EPA
also believes that the reference to coating as a film should be
retained. Therefore, the final definition incorporates both
concepts as follows:
"Coating means a material that is applied to the surface of
an aerospace vehicle or component to form a decorative or
functional solid film, or the solid film itself."
4.7 COATING UNIT
Comment: Commenter IV-D-29 suggested a change in the "flush
cleaning" definition in §63.742 (see Section 4.14) and in
proposed §63.744(d) (see Section 5.4) that would eliminate the
need for a "coating unit" definition and, therefore, recommended
deleting the definition of "coating unit."
Commenter IV-D-30 stated that it is not clear which
operations involve a "coating unit." The commenter believes that
the definition should define the beginning and ending points for
operations that involve coating units.
4-6
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Response: The EPA believes that the proposed requirement in
§63.744(d) for a closed container, collection system, or
equivalent control to be used in conjunction with flush cleaning
should be retained in the final rule. However, the definition
for "flush cleaning" has been revised (Section 4.14).
The term "coating unit" is a standard term used in the EPA's
and in States' coating regulations. In §63.744(d), it is
intended to designate all equipment (except spray guns) that may
be flush cleaned of coating materials prior to the application of
a different coating.
4.8 CONTROL DEVICE
Comment: Three commenters (IV-D-27, IV-D-29, IV-D-35)
pointed out that in order to maintain consistency with other
regulations, capture systems, such as exhaust hoods, should not
be covered by the definition of "control device." The commenters
believe that the definition as proposed by the EPA may also add
unnecessary confusion to the meaning of "control efficiency."
Based on the proposed definition .of control device, the
commenters claimed that "control efficiency" could be interpreted
as either "overall control efficiency" or "removal/destruction
efficiency." (An example of this confusion is in §63.746(d)(2)
of the proposed rule.) The commenters believe that the
definition should be revised as follows:
"Control device means an enclosed combustion destruction
device or and/or recovery system and,—for the purposes of
tins su.ljpiS.iL, includes the cs.ptm~csystcivi used to vent the
clui. S ti 1 OnS LlTCIii t-lic S Oil i. C e t. O ttlfe C Git it U S L1 Oil QcVlCS GIT
recovery—system used to destroy or recover a regulated air
pollutant generated by a source."
Commenter IV-D-35 also stated that clarification is needed
to confirm that the term "control device" is limited to VOC and
organic HAP control equipment.
Response: The EPA agrees that the use of the term "control
device" to include the capture system is inconsistent with its
use in other regulations, and could create confusion with regard
to the control efficiency requirements. Therefore, the term has
4-7
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been redefined as follows:
"Control device means destruction and/or recovery equipment
used to destroy or recover HAP or VOC emissions generated by
a regulated operation."
The term "control system" has also been added to §63.742 as
follows:
"Control system means a combination of pollutant capture
system(s) and control device(s) used to reduce discharge to
the atmosphere of HAP or VOC emissions generated by a
regulated operation."
4.9 DEPAINTING
Comment: Two commenters (IV-D-29, IV-D-35) believe that
changes to the definition of "depainting" are needed to confirm
that coverage is limited to permanent coatings and to exclude
temporary protective coatings, as the word "any" implies "all"
coatings. According to the commenters, since these requirements
should not apply to components (parts and subassemblies) prior to
final assembly of the entire "vehicle," clarification is also
needed to specify applicability to "completed" aerospace
vehicles. Commenter IV-D-35 recommended the following change:
"Depainting means the removal of any a permanent coating
from the outer surface of an a completed aerospace component
or vehicle whether by chemical or non-chemical means."
Response: The EPA agrees that the depainting provisions
should not apply to removal of temporary coatings. However, the
term "completed" would make the definition too restrictive, and
has not been added. A provision to exclude hand and mechanical
sanding operations from the definition has also been added (see
Section 4.32.7) . These operations have a much lower potential
for creating significant inorganic HAP emissions due to their
lower energy. Therefore, the final definition reads as follows:
"Depainting means the removal of a permanent coating from
the outer surface of an aerospace vehicle or component,
whether by chemical or non-chemical means. For non-chemical
means, this definition excludes hand and mechanical sanding,
and any other non-chemical removal processes that do not
4-8
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involve blast media or other mechanisms that would result in
airborne particle movement at high velocity."
4.10 DEPAINTING OPERATION
Comment : The same two commenters (IV-D-29, IV-D-35) stated
that the definition for "depainting operation" also needs to be
limited to permanent coatings and completed aerospace vehicles.
The commenters also stated that since washing (generally rinsing
with water) does not generate any additional HAP emissions, the
last sentence should be deleted from the definition. Thus, the
suggested definition is:
"Depainting operation means the use of a chemical agent,
media blasting, or any other technique to remove permanent
coatings from the outer surface of completed aerospace
components or vehicles. The depainting operation includes
W& S Ii i l^ O L t iife &£lfO£Aw6 COiUpOO&HC Olf VfeFilCJ.^ tO IT&IUOVc
AHCI CO& t ing ITcrS -i-ClU£ •
Response: As stated in the previous response, the EPA
agrees that this operation should be defined in terms of removal
of permanent coatings, and feels that use of the term "completed"
would make the definition unnecessarily restrictive. Also, the
Agency believes that the complete operation includes the washing
of residual materials from the vehicle or component, even if the
rinsing medium is non-HAP and does not generate any "additional"
HAP emissions. Therefore, the definition in the final rule
reads :
"Depainting operation means the use of a chemical agent,
media blasting, or any other technique to remove permanent
coatings from the outer surface of an aerospace vehicle or
component. The depainting operation includes washing of the
aerospace vehicle or component to remove residual stripper,
media, or coating residue."
4.11 ELECTROSTATIC SPRAY
Comment : Commenter IV-D-29 stated that when applying an
electrostatic coating, the coating is electrically charged and
the substrate is grounded. Since, technically, the substrate is
not charged, the proposed definition should be changed as
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follows:
"Electrostatic spray means a method of applying a spray
coating in which opposite — electrical charges — are — applied — to
the substrate and the coating an electrical charge is
applied to the coating and the substrate is grounded. The
coating is attracted to the substrate by the electrostatic
potential between them. "
Response: The EPA accepts this revision because it makes a
technical correction to the definition.
4.12 EQUIVALENT ORGANIC HAP AND VOC CONTENT LEVEL
Comment : Commenter IV-D-29 stated that "equivalent organic
HAP or VOC" combines two distinct definitions, one for equivalent
organic HAP content level and the other for equivalent VOC
content level. The commenter recommended that these definitions
be joined by the word "or" as shown below:
"Equivalent organic HAP and oj: VOC content level means tire
-------
will ensure a consistent list of exempt solvents in the event
that the 40 CFR §51.100 list is updated. The commenters
recommended that the definition be revised to read as follows:
"Exempt solvent means specified organic compounds that have
been determined by the EPA to have negligible photochemical
reactivity and are listed in 40 CFR 51.100." [List of
exempt solvents deleted.]
Commenter IV-D-27 was also concerned that it appears that
the EPA is promoting the use of ozone depleting compounds (ODC),
which are to be eliminated under title VI of the CAA, and
perfluoronated compounds (PFC's), which are suspected of
contributing to global warming.
Response: The EPA agrees that specific exempt solvents need
not be listed in the definition, and has incorporated the change
suggested by the commenters.
4.14 FLUSH CLEANING
Comment: Commenter IV-D-29 stated that the definition of
"flush cleaning" should be expanded to include coating equipment
(other than spray guns), as implied in proposed §63.744(d), and
to clarify that those cleaning operations that may include some
hand-wipe cleaning activities are excluded from the definition.
The commenter submitted this revised version:
"Flush cleaning means the cleaning of removal of
contaminants such as dirt, grease, oiland coatings, from an
aerospace vehicle or component or coating equipment by
passing solvent over, into, or through the vehicle or
component item being cleaned. The solvent may simply be
poured into the vehicle or component item being cleaned and
then drained, or be assisted by air or hydraulic pressure,
or by pumping. Those cleaning operations where wiping,
gcrubbing, mopping, or other hand or direct mechanical
action are used are not included."
Response: The EPA believes that adding "removal of
contaminants such as dirt, grease, oil, and coatings" will make
this definition consistent with the "hand-wipe cleaning
operation" definition. The EPA accepts the addition of "coating
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equipment" as another item that may be subject to flush cleaning.
The EPA has substituted "item being cleaned" for "vehicle or
component" to add clarification to the definition. The
commenter's revision which lists the hand cleaning operations has
also been incorporated in the definition. The phrase "or direct
mechanical action" is not being retained in the revision since
the scope and range of this term is not clear. Thus, the
definition in the final rule reads as follows:
"Plush cleaning means the removal of contaminants such as
dirt, grease, oil, and coatings from an aerospace vehicle or
component or coating equipment by passing solvent over,
into, or through the item being cleaned. The solvent may
simply be poured into the item being cleaned and then
drained, or be assisted by air or hydraulic pressure, or by
pumping. Hand-wipe cleaning operations where wiping,
scrubbing, mopping, or other hand action are used are not
included."
4.15 HAND-WIPE CLEANING OPERATION
Comment: Commenter IV-D-29 believes that technical
clarification is needed in the definition of "hand-wipe cleaning
operation" to indicate that solvent is not always applied to the
material; it is sometimes applied to the substrate and then
scrubbed, rubbed, or agitated by some means. The commenter
recommended the following revision:
"Hand-wipe cleaning operation means the removal of
contaminants such as dirt, grease, and oil from aerospace
components or vehicles by physically rubbing it with a
HLcL L.CT. J-cLx SL1C.IJ. &S> & ITJty / L^&JjGT/ Ol. OOt-urOU SWcLC t-llctu- ilo.5 OccTT
moistened with application of a cleaning solvent and
mechanical agitation and/or rubbing."
Response: The EPA believes that the proposed definition
covers the case where a cleaning solvent is applied directly to
the substrate being cleaned, since the porous cleaning material
would still become "moistened with a cleaning solvent" prior to
the cleaning action taking place.
4.16 HAZARDOUS AIR POLLUTANT (HAP)
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Comment: Commenter IV-D-42 noted that the proposed rule
defines HAP as those air pollutants listed under section 112(b)
of the Clean Air Act. The commenter stated that the section
112(b) list is subject to revision and, as currently written, the
proposed aerospace rule's standards will automatically apply to
materials containing HAPs that are listed after the aerospace
rule's date of adoption. The commenter claimed that the NESHAP
standards would then be applied to such materials without
consideration--as required in the MACT development process--of
feasibility, emission reduction cost, non-air quality health and
environmental impacts, and energy impacts. Therefore, the
commenter recommended that the HAP definition only include HAP
currently listed under section 112(b); the rule can be amended at
a later date if necessary.
Commenter IV-D-29 recommended that the definition of HAP be
revised as follows:
"Hazardous Air Pollutant (HAP) means any air pollutant
listed under in section 112(b) of the Clean Air Act
Amendments of 1990."
Response: The term "hazardous air pollutant" is defined in
the General Provisions, §63.2, as "any air pollutant listed in or
pursuant to section 112(b) of the Act." The "Act," in turn, is
defined in §63.2 as "the Clean Air Act (42 U.S.C. 7401 et seq. ,
as amended by Pub. L. 101-549, 104 Stat. 2399)." Since these
definitions are already contained in part 63, the EPA has avoided
duplication by deleting the proposed definition for "HAP" from
this rule.
4.17 HIGH VOLUME LOW PRESSURE (HVLP) SPRAY EQUIPMENT
Comment: Three commenters (IV-D-29, IV-D-35, IV-D-52)
recommended that the fluid delivery pressure cutoff of 100 psig
or less be dropped from the definition of "HVLP spray equipment."
Two of the commenters (IV-D-29, IV-D-35) stated that the fluid
delivery pressure requirement is irrelevant to the meaning of
HVLP spray equipment as currently used by State and local
agencies.
Commenter IV-D-52 recommended that the definition read as:
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"Equipment used to apply coatings by means of a gun which is
designed to be operated and which is operated between 0.1 and 10
psig air atomizing pressure measured dynamically at the center of
the air cap and at the air horns."
Response: The EPA has determined that sufficient reasons
have not been given to dictate a revision to the definition.
4.18 NON-CHEMICAL BASED DEPAINTING EQUIPMENT
Comment: Two commenters (IV-D-29, IV-D-35) recommended
revisions to the proposed definition of "non-chemical based
depainting equipment."
Commenter IV-D-35 recommended that this definition be
revised to read as follows:
"Non-chemical based depainting equipment means any
depainting equipment or technique, including media blasting
equipment, that does not rely on a liquid chemical stripper
to depaint an aerospace vehicle or component."
The commenter stated that this definition provides the
technically proper distinction between the liquid chemical
strippers and the solid chemical strippers (e.g., C02, SiO-,
acrylic, polyester, etc.).
Commenter IV-D-29 stated that technical clarification is
needed in this definition to show that media blasting equipment
is only one example of this kind of equipment. The commenter's
recommended definition clarifies that the use of chemical paint
softeners in conjunction with the non-chemical based depainting
equipment, as is common practice, is permissible and does not
constitute use of a "chemical stripper." (The commenter also
provided a definition for "softener;" see Section 4.32.10.) The
commenter recommended the following revisions:
"Non-chemical based depainting equipment means any
depainting equipment or technique, including, but not
limited to, media blasting equipment, that does not rely cm
a chemical stripper £ajQ depaint an aerospace vehicle or
component in the absence of a chemical stripper. Non-
chemical based depainting equipment can be used in
conjunction with a chemical paint softener."
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Response: The EPA accepts the revision offered by commenter
IV-D-29 because it adds more clarity to the definition. The EPA
will allow sources to use a chemical paint softener in
conjunction with non-chemical depainting techniques as long as
the softeners are HAP-free. The final sentence, "Non-chemical
based depainting equipment can be used in conjunction with a
chemical paint softener," has not been included in the
definition; however, this provision has been added to the
depainting standard, §63.746(a). The EPA has adopted the
following revised definition:
"Non-chemical based depainting equipment means any
depainting equipment or technique, including, but not
limited to, media blasting equipment, that can depaint an
aerospace vehicle or component in the absence of a chemical
stripper. This definition does not include mechanical
sanding or hand sanding." (See Section 4.32.7.)
4.19 PRIMER
Comment: Commenter IV-D-29 recommended that the definition
of "primer" be changed to recognize that one primer is
occasionally applied over another primer, so that "primer" may
not refer to the first layer exclusively. The commenter's
revised definition indicates that certain inorganic coatings,
such as conversion coatings, anodizing, and plating, are not
covered. Finally, the commenter pointed out that the proposed
rule's reference to specialty coatings that "are defined as"
infers there is a specific list of all specialty coatings. The
commenter offered the following revision to address these
concerns:
"Primer means the first layers of coating applied to the
surface of an aerospace vehicle or component. Primers are
typically used for corrosion prevention, protection from the
environment, functional fluid resistance, and adhesion of
subsequent coatings. Inorganic costings and coatings that
are 'defined as meet the definition of specialty coatings are
not included under this definition."
Commenter IV-D-35 recommended that the third sentence in the
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primer definition be changed to read as follows:
"Inorganic coatings and coatings that are defined as
specialty coatings are not included under this definition."
The commenter pointed out that inorganic coatings are not
covered under this regulation. The commenter also noted that the
current EPA definition for primer also describes conversion
coatings, which are exempt.
Response: The EPA accepts the first commenter's premise
that more than one layer of primer may be used. In order to
maintain the EPA's intention, the EPA has revised the definition
to state "Primer means the first layer and any subsequent layers
of identically formulated coating applied..." The EPA does not
believe that the inclusion of "inorganic coatings" is necessary
since the definition of coating does not specify whether organics
or inorganics are included. The definition adopted in the final
rule reads as follows:
"Primer means the first layer and any subsequent layers of
identically formulated coating applied to the surface of an
aerospace vehicle or component. Primers are typically used
for corrosion prevention, protection from the environment,
functional fluid resistance, and adhesion of subsequent
coatings. Coatings that are defined as specialty coatings
are not included under this definition."
In addition to this definition change, the EPA has expanded the
definition of "specialty coating" to provide a listing of the
specialty coatings exempt from the final rule requirements (see
Section 4.23). Therefore, the phrase "are defined as" is
pertinent.
4.20 RADOME
Comment: Two commenters (IV-D-29, IV-D-35) stated that
radar antennae are a subcategory of electronic transmitters and
receivers that have radomes. The commenters, therefore,
recommended the following revision to the definition of "radome":
"Radoxne means the non-metallic protective housing for radair
antenna electromagnetic transmitters and receivers (e.g.,
radar, electronic countermeasurp.sr etc.)."
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Response: The EPA accepts this revision because it is more
inclusive and technically accurate.
4.21 SELF-PRIMING TOPCOAT
Comment: Commenter IV-D-35 recommended that the definition
for "self-priming topcoat" be revised to read as follows:
"Self-priming topcoat means a coating that contains
corrosion inhibitors and is applied to an aerospace vehicle
or component for purposes of corrosion protection,
environmental protection, and functional fluid resistance
And tliAt is not siiJ^sto[u.sritiy uO]5CO2LG&ct.
The commenter stated that the proposed definition excluded
self-priming topcoats that are applied in two coats (i.e., the
first coat is subsequently "topcoated" with the same material),
self-priming topcoats that are reworked, self-priming topcoats
that are overcoated during subsequent maintenance repaint
operations, and self-priming topcoats that are not applied
directly to the item (i.e., they are applied over an existing
coating).
Response: The proposed rule provided a definition for
"self-priming topcoat" that conveys the EPA's intention that
self-priming topcoats should not be subsequently coated. The
commenter's point is noted by the EPA and the definition has been
revised to allow more than one layer of coating for identical
formulations. The statement in the proposed definition "for
purposes of corrosion protection" indicates that this coating
will inhibit corrosion. The commenter's recommended phrase
"contains corrosion inhibitors" was not retained in the revision
since the phrase could be interpreted to mean that this
formulation must contain specific components which inhibit
corrosion, whereas deleting this term does not restrict this type
of formulation. The EPA has adopted the following revision:
"Self-priming topcoat means a topcoat that is applied
directly to an uncoated aerospace vehicle or component for
purposes of corrosion prevention, environmental protection,
and functional fluid resistance. More than one layer of
identical coating formulation may be applied to the vehicle
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or component. The coating is not subsequently topcoated
with any other product formulation. "
4.22 SPACE VEHICLE
Comment: One commenter (IV-D-100) suggested the following
definition for "space vehicle":
"Space Vehicle means a man-made device, either manned or
unmanned, designed for operation beyond earth's atmosphere.
Also included is auxiliary equipment associated with test,
transport, and storage, which through contamination can
compromise the space vehicle performance."
The commenter stated that some of the hardware, tooling, and
test fixtures associated with space vehicles need to be coated
with the same coatings used on the space vehicle.
Response: The EPA's proposed definition did not include
reference to the auxiliary space hardware; therefore, the VOC and
HAP limits in the rule would have applied to the coating of this
equipment. The EPA accepts the arguments advanced by the
industry, and has revised this definition in accordance with the
suggestion of the commenter.
4.23 SPECIALTY COATING
Comment: Commenter IV-D-39 stated that the EPA has, in
setting limits for topcoats and primers, defined those coatings,
in part, in terms of their not being specialty coatings.
According to the commenter, at this time there is no established
list of specialty coatings. The commenter stated that specialty
coatings are coatings which (even if they otherwise would meet
the definition of topcoat or primer) have additional performance
criteria beyond those of topcoats or primers for specific
applications. The commenter also stated that the performance
criteria may include, but are not limited to, temperature or fire
resistance, substrate compatibility, antireflection, temporary
protection or marking, sealing, adhesively joining substrates,
rain erosion resistance, electric or radiation effect, or
enhanced corrosion protection. According to the commenter, since
the proposed definitions of topcoat and primer appear to refer to
a list not now in existence, appropriate clarification is needed
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in the language of the definitions.
Three other commenters (IV-D-2, IV-D-23, IV-D-30)
recommended that the specialty coatings not considered primers or
topcoats be specifically listed in the specialty coating
definition, because this definition as proposed is not specific
enough.
Commenter IV-D-31 stated that the proposed definition of
specialty coatings is not restrictive enough. The commenter
noted that the EPA proposed to define a specialty coating as one
that "had additional performance criteria beyond those of primers
and topcoats for specific applications." Since almost every
application has different performance criteria, any performance
criteria may be considered "additional." The commenter also
maintained that, since there is no baseline of generally
applicable performance criteria established, the definition of
specialty coating is potentially all-inclusive. According to the
commenter, if industry cannot offer a sufficiently restrictive
definition of specialty coating (or a list) and prove that no
emission reductions are achievable from a limited list of
processes, the EPA should simply not create a special category
for them. The commenter claimed that some categories of coatings
that the industry has sought to include within the specialty
coatings umbrella are widely used coatings with potentially
significant emissions.
Commenter IV-D-52 noted that the proposed definition for
specialty coatings is potentially rather broad and could likely
be interpreted in different ways. The commenter suggested that
one way to address this problem would be to more precisely
identify the various types of specialty coatings that are exempt.
The commenter acknowledged that the preamble to the proposed rule
pointed out that there are a large number of different specialty
coatings in use in this industry, many in relatively small
quantities. The commenter stated that, in their district, the
Aerospace Assembly and Component Coating Operations Rule
addresses specialty coatings by containing specific VOC standards
or exemptions for the more common specialty coatings and, in
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addition, a general low-usage coating exemption. The commenter
stated that the general exemption applies to aerospace coatings
with separate formulations that are used in volumes of less than
20 gallons per year provided that the total use of such low-use
coatings do not exceed 200 gallons per year (the exemption is
also dependent on the facility meeting recordkeeping and
notification requirements).
The commenter recommended that, if broad specialty coating
definitions are used, facilities should be required to petition
the implementing agency to establish the exemption status of
individual coatings. The commenter also recommended that a
facility be required to demonstrate that a particular coating
must meet increased performance criteria and cannot meet the
coating standards.
Response: The EPA has recognized since the beginning of
this rule development the necessity of excluding from coverage
certain specialized categories of coatings that are critical to
the performance of aerospace vehicles and have no acceptable low
VOC/HAP replacements. The Agency, with industry's cooperation,
compiled a list of several specialty coating categories, but
decided at proposal to not incorporate the list because of the
difficulty of accurately defining these coatings and due to the
concern that some categories would be inadvertently left out.
However, in considering these comments, the EPA has
concluded that an approach similar to that taken by commenter IV-
D-52 (a local control agency) would provide more specific
direction to facilities for which the use of specialty coatings
is a significant part of their operations. For this reason, the
definition of "specialty coating" has been expanded to include a
listing of the most common specialty coatings as indicated in the
information received from both OEM and rework facilities. Due to
the length of the listing, the definition specifies that the
listing is attached as an appendix to the rule.
A low-usage exemption similar to that suggested by commenter
IV-D-52 has been added as §63.741(g). This exemption applies to
primers, topcoats, and chemical milling maskants, and allows up
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to 50 gallons per year of each separate formulation, with a
combined annual limit of 200 gallons. Coatings otherwise
exempted in the rule are not to be included in these limits.
4.24 SPOT STRIPPING
Comment: Two commenters (IV-D-29, IV-D-35) recommended the
elimination of the phrase "where it is not technically feasible
to use a non-chemical depainting technique" from the definition
of "spot stripping." The commenters stated that technical
feasibility is a vague concept that must be assessed on a case-
by-case basis. According to the commenters, the technical
feasibility of a depainting method is dependent on at least three
factors: (1) the method cannot impede other maintenance
activities; e.g., crack detection; (2) the method cannot have
intrinsic physical limitations; e.g., reach into a sharp contour;
and (3) the method must have been approved by the original
equipment manufacturer (OEM) or weapon system manager for the
aerospace vehicle.
Commenter IV-D-29 recommended that "spot stripping" be
defined as follows:
"Spot stripping means the depainting of an area where it is
not 11 c rim c & l .L yLc&sxi^J-^ t o usss non- cij^ruj.o&-L cicpAmc ing
technique aerospace component which is not normally removed
from the completed aerospace vehicle before depainting or
the stripping of an aerospace vehicle or component subject
to a limit of 26 gallons for commercial aircraft and 50
gallons for military aircraft times the number of vehicles
produced per year."
The commenter stated that their revision allows OEM's and
military facilities the opportunity to occasionally depaint
entire aircraft to correct production flaws. According to the
commenter, the revised definition would limit the amount of
stripper that could be used for this purpose, consistent with the
stripper exemptions contained in proposed §63.746 (c).
Commenter IV-D-35 recommended that "spot stripping" be
defined to mean the depainting of an area on an aerospace vehicle
subject to a limit of 26 gallons of chemical stripper for
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commercial aircraft and 50 gallons for military aircraft based on
the number of vehicles produced or serviced per year.
Commenter IV-D-2 recommended that the decision on technical
feasibility be left to the permitting agency and any
authorization for the use of HAP-containing chemical strippers
for spot stripping be contained in the title V (part 70) permit.
This commenter recommended that "spot stripping" be defined as
follows:
"Spot stripping means the depainting of an area identified
in a part 70 permit, where the permitting authority has
determined that it is not technically feasible to use a non-
chemical depainting technique."
Response: The spot stripping exemption was provided so that
companies would be allowed the use of chemical strippers where
the substrate or a physical limitation necessitated chemical
stripper use. Specifically, this exemption was provided for
companies that use non-chemical depainting methods (i.e., dry
media blasting). The exemption was not intended to allow
unrestrained chemical stripper use of 26 gallons for commercial
aircraft and 50 gallons for military aircraft. The EPA believes
that if the phrase "where it is not technically feasible to use a
non-chemical depainting technique" is not retained in the
definition, facilities may abuse the intent of the exemption. As
such, the commenter's revision which adds "which is not normally
removed" has not been included because this revision would
further dilute EPA's intention. Additionally, the gallons of
exempt stripper have not been included in the definition, but
will remain in the standard. The commenters' recommendation that
the exemption be based on the "number of vehicles serviced or
produced per year" also has not been incorporated into the final
definition, since the number of vehicles serviced or produced
might have no correlation to the number of vehicles depainted.
4.25 SPRAY GUN
Comment: Commenter IV-D-29 believes that the following
definition for "spray gun" is more generally applicable than the
EPA's proposed definition:
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"Spray gun means a device that uses air pressure or all' flow
to atomizes a coating or other material and projects the
atomized coating participates or other material onto a
substrate."
Response: The EPA accepts this revision because it
simplifies and clarifies the definition.
4.26 STRIPPER
Comment: Commenter IV-D-29 stated that stripper is also
used to remove coatings other than primers and topcoats. In
addition, while stripping does remove the coating's residue, the
commenter believes that it is not necessary to include this in
the definition. The commenter also noted that the addition of
the word "permanent" in reference to coatings excludes from the
definition materials used to remove temporary protective
coatings, which are outside the scope of this definition. The
commenter recommended the following revision:
"Stripper means a liquid that is applied to an aerospace
component or vehicle to remove primer,—topcoat,—or—coating
I'gsidue permanent coatings such as primers and topcoats."
Commenter IV-D-35 recommended that the definition for
"stripper" be revised to read as follows:
"Stripper means a liquid that is applied to an aerospace
component or vehicle to remove a layer or layers of primer,
topcoat, or self-priming topcoat residue. Stripper does n^ot
include hand wipe cleaners."
The commenter stated that the proposed definition would
include hand-wipe cleaners which remove coating residue and
soap/water which removes incidental quantities of coating
residue.
Response: The EPA agrees with the first commenter and has
included the following revised definition in the final rule:
"Stripper means a liquid that is applied to an aerospace
vehicle or component to remove permanent coatings such as
primers and topcoats."
4.27 SURFACE PREPARATION
Comment: Commenter IV-D-29 stated that the activation of a
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surface is not necessarily "immediately" followed by the
application of a coating, and recommended the following revision
to the proposed definition of "surface preparation":
"Surface preparation means the removal of contaminants from
the surface of an aerospace component or vehicle, or the
activation or reactivation of the surface immediately prior
to the application of a coating."
Response: Since the term "immediately" is restrictive and
difficult to define, it has been deleted from the final
definition. To indicate that this activity is meant to prepare
for a coating operation, the phrase "in preparation for" has been
included in the definition. In addition, the phrase "or
reactivation" has been added. Thus, the EPA's final definition
reads as follows:
"Surface preparation means the removal of contaminants from
the surface of an aerospace vehicle or component, or the
activation or reactivation of the surface in preparation for
the application of a coating."
4.28 TOPCOAT
Comment: Commenter IV-D-29 stated that a technical
clarification is needed in the definition of "topcoat."
Specifically, the commenter maintained that "are defined as"
infers that there is a specific list of all specialty coatings.
The commenter, therefore, recommended the following revisions:
"Topcoat means a coating that is applied over a primer on an
aerospace vehicle or component for appearance,
identification camouflage, or protection, or any self-
priming topcoat. Coatings that are defined as meet the
definition of specialty coatings are not included under this
definition."
Response: This change is unnecessary since a specific list
and definitions for specialty coatings have been added to the
final rule (see Section 4.23).
4.29 TOUCH-UP AND REPAIR OPERATION
Comment: Commenters IV-D-27, IV-D-29, and IV-D-37 suggested
that the proposed definition of "touch-up and repair operation"
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should be revised. The commenters noted that the proposed
definition would limit permissible touch-up and repair painting
operations to a total area not to exceed 4 square feet per
aerospace vehicle. The commenters concur with AIA that
determining accurately the total area of small touch-up
operations performed during the assembly of an aerospace vehicle
is not feasible. Moreover, the commenters claimed that the same
considerations apply equally, if not more so, with respect to
aircraft maintenance activities in which components of an
aircraft must be spread throughout a large and decentralized
maintenance facility for simultaneous rework and repair. The
commenters claimed that, because in-service daily-use commercial
aircraft sustain damage far in excess of that encountered during
initial assembly and flight testing, the 4 square foot limitation
for touch-up and repair painting is unduly restrictive for
maintenance facilities, particularly with regard to large
passenger aircraft, such as Boeing 747's and DC-10's. The
commenters recommended that the 4 square foot limitation be
eliminated from the definition of "touch-up and repair
operation," stating that the terms of the definition itself will
effectively limit the extent to which such exempted painting
operations may be employed.
Commenter IV-D-39 stated that, while they support the
proposed exemptions from the primer and topcoat operations
standards, the definition of touch-up should be revised to read
as follows "(1) Touch-up, including, for example, repair of
scratched surfaces or damaged paint..." According to the
commenter, since "touch-up" applications may be appropriate for
areas that would not be described as "scratched" or "damaged"
(e.g., for improved aesthetics), this definition is overly
restrictive. The commenter believes that, rather than attempting
to cover every conceivable type of touch-up, it is better to make
the types of applications illustrative rather than restrictive,
leaving it to the regulator and the source to determine what
constitutes touch-up in actual operation.
Comments were also received (IV-E-2) that some painting
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operations may be performed in nonstandard locations (such as in
flight areas), and these "out-of-sequence" coating operations
should be exempted form the requirement to use certain
application methods.
Response: The EPA agrees that the total area of touch-up on
a given vehicle could be difficult to estimate and verify.
Therefore, a revised definition which eliminates the 4
ft2/vehicle cutoff is included in the final rule. The EPA
believes that its description of what constitutes touch-up is
sufficiently general to cover any situation. Out-of-sequence
coating has also been included in the definition to exempt this
type of operation from the requirement to use certain specific
application techniques. The final definition reads as follows:
"Touch-up and repair operation means that portion of the
coating operation that is the incidental application of
coating used to cover minor imperfections in the coating
finish or to achieve complete coverage. This definition
includes out-of-sequence coating."
4.30 TYPE II ETCHANT
Comment: Commenter IV-D-6 stated that the proposed
definition for "Type II etchant" is imprecise and overly broad.
The commenter explained that Type II etchants have a very
specific composition of chemical constituents. The commenter's
company uses an etchant that contains amines, but at a
concentration well below what is considered a Type II etchant in
the aerospace industry. The commenter recommended that a Type II
chemical milling etchant be more precisely defined as an etchant
with a specific range of amine, sulfide, caustic, and aluminum
concentrations.
Response: The EPA believes that the definition published in
the proposed rule conveys EPA's intention to specify that Type II
etchants are strong sodium hydroxide solutions containing amines.
Type I etchants, on the other hand, do not contain amines. The
EPA will maintain the current definition in order to clarify its
intent with respect to the regulation of chemical milling
maskants.
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4.31 VOLATILE ORGANIC COMPOUND (VOC)
Cpmment : Commenter IV-D-29 stated that the definition of
VOC should be changed to be consistent with other EPA and State
rules and to clarify the applicability of "organic compound."
The commenter also stated that, in the absence of these changes,
every time the EPA revises its general definition in 40 CFR
§51.100, this definition would have to go through separate
rulemaking to accommodate the changes. The commenter believes
that it would be preferable to simply refer to the general EPA
definition to avoid time-consuming additional rulemaking.
Therefore, the commenter recommended that the definition of VOC
read as follows:
"Volatile organic compound (VOC) means any compound defined
as VOC in 40 CFR Part 51.100. "
This comment is similar to the comment in Section
4.13. Therefore, the EPA has revised the definition in
accordance with the comment .
4.32 RECOMMENDATIONS FOR INCLUSION IN THE RULE
4.32.1 Cleaning Operation
Comment : Commenter IV-D-29 believes that the regulation is
confusing without some definition that would group cleaning
operations together, and proposed the following:
"Cleaning operation means collectively spray gun, hand-wipe,
and flush cleaning operations."
Response: The EPA agrees with the commenter and has added
this definition to §63.742.
4.32.2 Compliant Material
Comment : Commenter IV-D-27 felt that a definition for
"compliant material" should be added in order to make coating
manufacturers responsible for assuring that coatings comply with
VOC and/or HAP limits. This would eliminate the need for
aerospace companies to perform duplicative tests individually.
The following definition was suggested:
"Compliant material means a material certified by the
coating manufacturer to be compliant with the applicable VOC
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and/or HAP content requirements of this regulation."
Response: Under this NESHAP regulation, only the owner or
operator of a facility containing an affected aerospace operation
can be directly regulated. Therefore, enforcement against
coating manufacturers due to the use of non-compliant coatings by
aerospace firms would not be practicable. The EPA believes that
the market pressures imposed by purchasers of aerospace coatings
will be sufficient to persuade coating suppliers to provide
adequate assurances concerning their product formulations. Thus,
the end result sought by the commenter should be realized without
the need for imposing regulatory requirements on the producers of
these coatings.
4.32.3 Confined Space
Comment: Commenter IV-D-29 recommended using "confined
space" instead of "limited access space" to support the exclusion
under solvent cleaning. The commenter supplied the following
definition of "confined space":
"Confined space means a space that: (1) is large enough and
so configured that an employee can bodily enter and perform
assigned work; (2) has limited or restricted means for entry
or exit (for example, fuel tanks, fuel vessels, and other
spaces that may have limited means of entry); and (3) is not
designed for continuous employee occupancy."
Response: The EPA finds that the suggested definition
clarifies the exempt cleaning operations in §63.744(e)(6), and is
more appropriate for this purpose than use of the term "limited
access space" as proposed (which applies principally to coating
operations). Therefore, this provision incorporates the term
"confined spaces" and the suggested definition is added to
§63.742.
The term "limited access space" is being retained in order
to define the situation exempted [in §63.745 (f) (3) (i)] from the
primer/topcoat application equipment requirements.
4.32.4 Electrodeposition of Paint
Comment: Commenter IV-D-29 recommended that the following
definition for "electrodeposition of paint" be added to make this
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technique possible as an acceptable method of application in
§63.745{f)(1):
"Electrodeposition of paint means the application of a
coating using a water-based electrochemical bath process.
The component being coated is immersed into a bath of the
coating. An electric potential is applied between the
component being coated and an oppositely charged electrode
hanging in the bath. The electric potential causes the
ionized coating to be electrically attracted, migrated, and
deposited on the component being coated."
Response: This application technique provides a MACT level
of control through its high application efficiency. Therefore,
it has been added to §63.745 (f) (1) and is defined in §63.742 of
the final rule.
4.32.5 Inorganic HAP
Comment: Commenter IV-D-29 stated that the addition of a
definition as follows for "inorganic HAP" is necessary to clarify
that the inorganic HAP referred to in this subpart include HAP
listed in section 112(b) of the Clean Air Act Amendments of 1990
that are not organic:
"Inorganic HAP means a compound which is listed in section
112(b) of the Clean Air Act Amendments of 1990 and which is
not organic."
Commenter IV-D-30 recommended adding the following
definition for "inorganic HAP":
"Inorganic Hazardous Air Pollutant means a compound that is
listed in the Clean Air Act §112(b) and which is not
organic."
Response: As discussed in Section 4.16, the term "HAP" has
been defined in the General Provisions and does not need to be
defined again in this NESHAP. Therefore, the EPA has added a
definition for "inorganic HAP" as follows:
"Inorganic hazardous air pollutant (HAP) means any HAP which
is not organic."
4.32.6 Maintenance Painting
Comment: Commenter IV-D-35 recommended that the following
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definition for "maintenance painting" be added to the rule:
"Maintenance painting means painting operations after non-
destructive inspection (NDI), corrosion rework, composite
replacement, metal panel replacement, aerospace vehicle
modification, panel access, or other maintenance activities
to insure aircraft structural integrity."
The commenter proposed that the above definition is necessary
since maintenance painting should be exempt from the rule.
Response: It was not the EPA's intent in these standards to
exempt routine painting operations performed in reworking
(maintaining and repairing) aerospace vehicles or components.
Therefore, this definition has not been added to the final rule.
4.32.7 Mechanical Sanding
Comment: Commenter IV-D-35 recommended that the following
definition be added to the rule:
"Mechanical sanding means aerospace vehicle surface
conditioning to include the use of directional and random
orbital tools and aluminum oxide or nylon abrasive pads for
the purpose of corrosion rework, substrate repair, prepaint
surface preparation, and other maintenance activities."
The commenter proposed that maintenance sanding should be exempt
from the rule, thus making the above definition necessary.
Commenter IV-D-29 also stated that a definition of
"mechanical sanding" should be included to allow the exclusion of
mechanical sanding as defined from the depainting control
requirements. The commenter recommended that the following
definition be added:
"Mechanical sanding means aerospace vehicle or component
surface conditioning and includes the use of directional and
random orbital abrasive tools and aluminum oxide or nylon
abrasive pads."
Response: The EPA has added a definition of this term to
the rule and is exempting mechanical sanding from the depainting
control requirements. The EPA believes that sanding has less
potential to emit air emissions than chemical or blast forms of
depainting. Therefore, the final rule includes the following
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definition:
"Mechanical sanding means aerospace vehicle or component
surface conditioning which uses directional and random
orbital abrasive tools and aluminum oxide or nylon abrasive
pads for the purpose of corrosion rework, substrate repair,
prepaint surface preparation, and other maintenance
activities."
The definition for "depainting operation" has also been
revised (Section 4.10) to exclude hand and mechanical sanding.
4.32.8 Organic HAP
Comment; Commenter IV-D-29 stated that the addition of a
definition for "organic HAP" is necessary to clarify that the
organic HAP referred to in this subpart include organic HAP
listed in section 112(b) of the Clean Air Act Amendments of 1990:
"Organic HAP means an organic compound which is listed in
section 112(b) of the Clean Air Act Amendments of 1990."
Commenter IV-D-30 recommended adding the following
definition for "organic HAP":
"Organic Hazardous Air Pollutant means organic compound that
is listed in the Clean Air Act §112(b) and acts as a
solvent."
Response: The term "HAP" has been defined in the General
Provisions (see Section 4.16). The EPA has added a definition
for "organic HAP" as follows:
"Organic hazardous air pollutant (HAP) means any HAP which
is organic."
4.32.9 Ozone Depleting Compound
Comment: Commenter IV-D-30 recommended adding a definition
for "ozone depleting compounds" to specify those specific
materials found in section 602 (a) of the Clean Air Act.
Response: The commenter did not provide any rationale for
including this definition, so this change to the rule has not
been made.
4.32.10 Softener
Comment: Commenter IV-D-29 stated that paint softeners are
weak or slowly acting chemical strippers used in conjunction with
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some non-chemical based depainting techniques to assist in the
removal of primers and topcoats. The commenter believes that
softeners should be treated like strippers for Aerospace NESHAP
purposes. The commenter claimed that their use supplements non-
chemical based depainting equipment and, therefore, should not
negate the "non-chemical based" status of this equipment. The
commenter stated that softeners may contain VOC and need not
contain HAP. The commenter also felt that the no-HAP condition
should be tied to the MSDS reporting concentrations (0.1 percent
for carcinogens and 1 percent for non-carcinogens) to avoid
imposing on the user the burden of determining the absence of HAP
below this level. The commenter, therefore, recommended that the
following definition be added:
"Softener means a liquid that is applied to an aerospace
component or vehicle to degrade coatings such as primer and
topcoat specifically as a preparatory step to subsequent
depainting by non-chemical based depainting equipment.
Softeners may contain VOCs but shall not contain any HAP
reported as exceeding the OSHA de minimis threshold
concentration as defined by 29 CFR §1910.1200(g)."
Commenter IV-D-35 expressed similar arguments and
recommended that the following definition for "softener" be added
to the rule:
"Softener means a liquid that is applied to an aerospace
component or vehicle to degrade coatings such as primer and
topcoat specifically as a preparatory step to subsequent
depainting by non-chemical based depainting equipment.
Softeners may contain VOCs but may not contain HAP if listed
in the appropriate MSDS."
Response: The EPA agrees that the use of softeners is
necessary to some non-chemical depainting techniques and their
use should be allowed under the final rule. Therefore, the
following definition for "softener" has been added to the rule:
"Softener means a liquid that is applied to an aerospace
vehicle or component to degrade coatings such as primers and
topcoats specifically as a preparatory step to subsequent
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depainting by non-chemical based depainting equipment.
Softeners may contain VOC but shall not contain any HAP as
determined from MSDS's or manufacturer supplied
information."
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5.0 CLEANING OPERATIONS
5.1 HOUSEKEEPING MEASURES
Comment: Commenter IV-F-1 pointed out that "solvent-laden"
as used in the proposed rule (§63.744(a) (l)), could be
interpreted to mean that a cleaning rag must actually be laden
with solvent at the time of completion of the operation as
opposed to having the solvent laden at some point during the
cleaning procedure. The commenter requested a definition or
clarification of "solvent-laden."
Response: If "solvent-laden" were defined as containing
solvent, then commenters might ask for clarification on
concentration, vapor pressure, wetness, etc. The EPA chooses not
to include a clarification or definition of the term solvent-
laden. The term reflects the EPA's intent that cloth, paper, or
other materials that contain solvent and are not currently being
used in a cleaning operation should be stored in a closed
container to prevent evaporation and release of VOCs, HAPs, and
ODCs.
Comment: Two commenters (IV-D-27, IV-D-29) noted that
proposed §63.744(a) requires aqueous cleaners to comply with
housekeeping measures. The commenters stated that subjecting
aqueous cleaners containing no organic HAP to these housekeeping
requirements would add no significant environmental benefit and
would place an unnecessary burden on industry.
Commenter IV-D-30 pointed out that the proposed standard
identifies all cleaning materials as "cleaning solvents." The
commenter believes that this will require soapy water to be
considered the same as organic cleaners. The commenter stated
that certain housekeeping measures are necessary for many organic
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cleaners, but it does not follow that the same measures should be
required for many aqueous materials. The commenter recommended
that the EPA require stringent measures only for organic cleaning
materials.
Commenter IV-D-29 recommended that §63.744(a) be revised as
follows:
"§63.744(a) Housekeeping measures. Each owner or operator
of a new or existing cleaning operation subject to this
subpart shall comply with the requirement in paragraphs
(a)(1) through (a)(3) of this section unless the solvent
used is classified as an aqueous cleaning solvent type under
Table 3."
Commenter IV-D-27 recommended rewording §63.744(a) as
follows:
"§63.744 Standards: Cleaning operation.
(a) Housekeeping measures. Each owner or operator of a new
or existing cleaning operation subject to this subpart shall
comply with the requirements in paragraphs (a)(1) through
(a)(3) of this section unless the solvent used is classified
as an aqueous cleaning solvent that contains no organic HAP
as identified in Table 3."
The commenter also believes that this exemption should be added
as number 12 in the "Exempt Cleaning Operations" (§63.744).
Response: The EPA accepts the commenters1 recommendations
and agrees that the emissions from non-HAP, non-VOC cleaning
solvents should not be subject to the housekeeping measures.
Therefore, the EPA has exempted aqueous cleaning solvents and
cleaning solvents that contain no HAP or VOC from the
housekeeping requirements.
Comment: Commenter IV-D-37 noted that proposed
§63.744(a)(1) would require solvent-laden cloth, paper, or other
material used in cleaning aerospace vehicles or components to be
placed in bags or other closed containers immediately after use.
The commenter objected to this requirement and considered it to
be unnecessarily costly, impractical, and ineffective. The
commenter claimed that by the time rag cleaning operations are
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completed, most fugitive emissions will already have occurred.
The commenter also claimed that the HAP emissions that are
prevented by this bagging requirement would not be justified by
the significantly increased waste disposal costs.
The commenter, therefore, recommended the deletion of
proposed §63.744(a)(1). According to the commenter, if the
provision is retained in the final rule, an exception to the
bagging requirement should at least be authorized if the rag or
cloth is dry to the touch upon completion of the cleaning
operation.
According to commenter IV-D-30, compliance with the
requirement for "total containment of vapors" depends largely on
the definition of "total." Therefore, the commenter recommended
changing the last sentence of §63.744(a)(1) to read: "Use bags
and containers of such design so as to reasonably contain the
vapors of the cleaning solvent."
Commenter IV-D-29 noted that this portion of the rule also
states that facilities must "[u]se bags and containers of such
design so as to contain the vapors of the cleaning solvent." The
commenter sought clarification from the EPA since no bag or
container can "contain" all of the vapors of the cleaning
solvent. Therefore, this commenter also believes that the bags
and containers should be required to "reasonably" contain the
vapors.
Response: The EPA has gathered information that
demonstrates emission reductions have been achieved in practice
by facilities using the bagging and storage requirements. The
EPA is compelled to require common sense emission controls when
the technology required for implementation of this housekeeping
measure amounts to placing cloths and other materials in an
enclosed container to contain the vapor emissions of the cleaning
solvents.
Comment: Commenter IV-D-27 stated that their clean-up
applications often require the use of cotton-tipped swabs for
smaller projects. The commenter claimed that the housekeeping
burden should be removed as it would add no appreciable
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environmental benefit to this type of waste.
Commenter IV-D-29 noted that proposed §63.744(a)(1) requires
proper handling of solvent-laden cloth, paper, or "other
material." The commenter believes that the category of "other
material" is too broad and should be narrowed to apply only to
absorbent applicators.
The same commenter (IV-D-29) noted that the proposed rule
also requires these materials to be placed in bags or other
closed containers "immediately after use." The commenter was
concerned that the use of this phrase will lead to improper
enforcement. The commenter believes that the requirement to
place the rag in the closed container "immediately after use"
will cause a 15 to 25 percent increase in a facility's
wastestream. Therefore, this commenter recommended that this
language be changed to "upon completing use."
Commenter IV-D-29 recommended that §63.744(a)(1) be revised
as follows:
"(1) Place solvent-laden cloth, paper or any other
absorbent applicators used in cleaning aerospace vehicles or
components in bags or other closed containers upon
completing use. Ensure that these bags and containers are
kept closed at all times except when depositing or removing
cloth or paper from the container. Use bags and containers
of such design so as to reasonably contain the vapors of the
cleaning solvent."
Response: The EPA accepts the commenter's recommendation
that cotton-tipped swabs do not add appreciable emissions to the
atmosphere. The EPA maintains that requiring that solvent-laden
cloths to be enclosed immediately after use does not increase a
facility's waste stream. The facility is free to continue using
the application device as long as they choose. Containment of
the vapor emissions from the solvent application devices when not
in use has no connection to the quantity of waste resulting from
the facility's cleaning operations.
Therefore, the EPA has adopted the following revision for
§63.744 (a)(1):
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"(a)(1) Place solvent-laden cloth, paper, or any other
absorbent applicators used for cleaning aerospace vehicles
or components in bags or other closed containers immediately
after use. Ensure that these bags and containers are kept
closed at all times except when depositing or removing these
materials from the container. Use bags and containers of
such design so as to contain the vapors of the cleaning
solvent. Cotton-tipped swabs used for very small cleaning
operations are exempt from this requirement."
5.2 HAND-WIPE CLEANING SOLVENT REQUIREMENTS
5.2.1 Vapor Pressure Limits
Comment: Commenter IV-D-31 stated that cleaning with
solvents at vapor pressures of up to 45 millimeters of mercury
(mm Hg) at 20 degrees Celsius does not provide for the maximum
achievable reduction. The commenter noted that the record
indicates that some facilities are subject to a 25 mm Hg
standard. The industry has not shown that there are any physical
differences between most facilities and those meeting the more
stringent 25 mm Hg standard. The commenter stated that the
average of the best performing 12 percent of existing sources
corresponds to a vapor pressure of less than 45 mm Hg and that
the proposed emission limitation cannot be less stringent than
the emission limitation achieved by the average of the best
performing 12 percent. According to the commenter, the statute
does not permit the EPA, under any circumstances, to allow an
emission limitation less stringent than the mathematically
determined floor.
Response: The EPA gathered information indicating that only
a few sources have demonstrated that a 25 mm Hg vapor pressure
limit is achievable. The EPA believes that the sources that are
complying with the 25 mm Hg vapor pressure limit are not wholly
representative of the aerospace industry. According to section
114 information, a 45 mm Hg limit represents the MACT floor.
Comment: Commenter IV-D-22 stated that it is not clear
whether the 45mm Hg vapor pressure cutoff level applies to all
solvents, VOC solvents, or only HAP solvents. The commenter
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suggested that under the proposed rule HAP-listed solvents, such
as perchloroethylene, MIBK, and 2-butoxy ethanol could be used
for hand-wipe cleaning because their vapor pressures are less
than 45 mm Hg, while relatively nontoxic solvents such as acetone
and HFC-43-10 would be forbidden. The commenter noted that the
EPA is about to propose rules exempting from VOC regulations both
HFC-43-lOmee and acetone. In addition, with regard to
perchloroethylene, the commenter stated that the EPA also intends
to propose to exempt perchloroethylene from VOC regulation and
that if the Aerospace NESHAP does not restrict its use,
perchloroethylene could be adopted in place of high ozone
depleting VOC and HAP solvents. The commenter maintained that
such an outcome would not be good public policy. The commenter,
therefore, recommended a restriction on the usage level of listed
HAP and new unscrutinized solvents rather than a restriction on
vapor pressure.
Response: In order to allow facilities to continue to use
cleaning solvents that pose minimal emissions concerns, the EPA
specified that non-HAP, non-VOC cleaning solvents are exempt from
the cleaning standard. Paragraph 63.744(b) has been revised as
follows:
"(b) Hand-wipe cleaning. Each owner or operator of a new or
existing hand-wipe cleaning operation (excluding cleaning of
spray gun equipment performed in accordance with paragraph
(c)(3) of this section) subject to this subpart shall use
cleaning solvents that meet one of the requirements
specified in paragraphs (b)(1), (b)(2), and (b)(3) of this
section. Cleaning solvent solutions that contain no HAP or
VOC are exempt from the requirements in paragraphs (b) (1),
(b) (2), and (b) (3)."
5.2.2 Aqueous Cleaners
Comment: Commenter IV-D-29 claimed that aqueous cleaning
solvents should be defined as 60 percent (not 80 percent) water.
The commenter stated that some industry members are currently
using low volatility cleaners such as butyl carbitol solution,
which would not be considered aqueous under the definition in
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Table 3. The commenter also noted that other "aqueous" cleaners
such as Daracleane, Amberclean, and Brulin, are as low as 60
percent water and thus would also not be allowed to be used under
this rule.
The commenter pointed out that aqueous "solvents," referred
to in the Table, are generally solutions of concentrates and
water. The commenter believes that the use of the term
"solution" is more correct and will cause less confusion.
In addition, the commenter stated that since it is difficult
to prove 100 percent solubility, this term should be removed.
The commenter suggested that rather than requiring solvents to be
"non-flammable and non- combustible, " the rule should use the
flash point. The commenter stated that this is consistent with
DOT regulations and is defined by a specific ASTM. The commenter
stated that since the manufacturers are required to classify
their materials for transportation purposes, the EPA should
utilize this readily available information.
Therefore, the commenter recommended the following revisions
to the composition requirements for aqueous cleaners:
"Cleaning solvents in which water is the primary ingredient
(> #& ££ percent of solution solvent jlas applied^! must be
water) . Aqueous solvents must be -non -flammable, — 11011-
\^, OIYu->Xl£ t- -L.O J. O f cll/iQ. ix/Aj t)*3 i Cciii... £Oa.\iI.xJ-c xll WS.WW.L «~
surfactants, and bioenzyme mixtures and nutrients may be
combined with the water along with a variety of additives
such as organic solvents (e.g., high boiling point
alcohols), builders, saponifiers, inhibitors, emulsifiers,
pH buffers, and antifoaming agents. Aqueous solutions must
have a flash point greater than 200°F (as_ reported by the
manufacturer) and the solution must be miscible with water. "
Response: The EPA believes that the final rule allows
facilities many options of compliance with the hand-wipe cleaning
solvent requirements. Facilities remain free to use any product
as long as the product meets the requirements specified in the
rule.
The EPA is adopting the language of "solvent solution" in
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the rule in order to acknowledge that the cleaning agents used in
the operation may be solutions of concentrates and water or a
pure component.
The EPA is also adopting the commenter's recommendation that
a flash point temperature be used instead of stating that an
aqueous solution must be non-flammable and non-combustible.
The EPA has adopted the following revision for aqueous
cleaning solution composition requirements in Table 3:
"Cleaning solvents in which water is the primary ingredient
(>80 percent of solvent solution as applied must be water).
Detergents, surfactants, and bioenzyme mixtures and
nutrients may be combined with the water along with a
variety of additives such as organic solvents (e.g., high
boiling point alcohols), builders, saponifiers, inhibitors,
emulsifiers, pH buffers, and antifearning agents. Aqueous
solutions must have a flash point greater than 93° C (200°F)
(as reported by the manufacturer) and the solution must be
miscible with water."
5.2.3 General Comments
Comment: Commenter IV-D-23 expressed concern that the use
of high-vapor pressure solvents for a list of exempt cleaning
operations could be employed as a defense to an enforcement
action. The commenter believes that it is not feasible (1) for a
facility to keep records of the type of cleaning operation and
the amount and type of hand-wipe solvent used by each employee
each day, or (2) for the permitting agency to review these
records to determine if the activities performed by each
individual employee could be an exempt cleaning operation.
For these reasons, the commenter recommended a facility-wide
performance standard for hand-wipe cleaning. The commenter noted
that the control effectiveness of the proposed rule estimated in
the background information document (BID) was 55 percent. To
achieve a comparable emission reduction, the commenter
recommended that the EPA allow the permitting agency to require a
55 percent reduction in the use of hand-wipe solvents from the
1990 base year as an alternative. According to the commenter,
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such a strategy would be easy to enforce, minimize recordkeeping,
and achieve the same environmental benefit estimated in the BID.
Commenter IV-D-12 suggested that there be only two classes
of solvent, one for operations that require the use of HAPs or
VOCs (i.e., exempt solvents) and those which may be cleaned
satisfactorily with solvents of low or no HAP or VOC content.
The commenter believes that this action would simplify the
recordkeeping and the regulation. For solvents of low or no HAP
or VOC content, the commenter recommended that the limitation be
based on a daily average weight of HAP or VOC per gallon, rather
than vapor pressure. The commenter stated that using a pounds
per gallon limit would make compliance and enforcement much more
straightforward.
Response: The EPA has spent significant time and resources
developing an emission standard which it believes to be
enforceable. Numerous State and local regulatory agencies have
been involved in the development of the standard. The EPA
believes that the standard, as promulgated, provides affected
sources and State and local agencies with enforceable
requirements.
In order to provide additional flexibility, the EPA has
added a pollution prevention alternative to the composition
requirements specified in Table 3 (§63.744 (b)(3)). A facility
may demonstrate that the volume of hand-wipe solvents used has
been reduced by 60 percent using a baseline established by the
permitting authority. The facility must demonstrate that this
alternative compliance plan will achieve emission reductions
equivalent to the cleaning solvent composition requirements.
Comment: Commenter IV-D-12 stated that the section on hand-
wipe cleaning provides little incentive for using aqueous or low
vapor pressure hydrocarbon based solvents as listed in Table 3.
The commenter also stated that having the option of using
cleaning solvents with a composite vapor pressure of 45 mm Hg or
less (that may have substantial organic HAP content) does not
provide much incentive for using aqueous cleaning solvent. The
commenter also suggested that requiring slightly more
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recordkeeping as the only consequence of using the higher vapor
pressure VOC solvent will not discourage persons from using these
solvents.
Response: The EPA set the vapor pressure limits based on
data obtained from the industry. Many comments have been
received on the recordkeeping requirements for hand-wipe cleaning
solvents indicating that many facilities would like to delete the
daily and monthly recordkeeping requirements. The EPA has
deleted the daily recordkeeping requirements for noncompliant
cleaning solvents from the final rule. The EPA believes that
monthly and annual recordkeeping requirements provide facilities
with the flexibility to implement a compliance strategy while
alleviating recordkeeping burdens.
Comment: Commenter IV-D-35 recommended that the EPA add
"semi-aqueous" cleaners to the approved composition list of
cleaning solvents. The commenter stated that the aerospace
industry has invested significant resources to test and qualify
non-ODC cleaners. The commenter provided a list of solvents
which have either been tested and found acceptable by a DoD
organization or are being tested now. The commenter, therefore,
recommended that the EPA evaluate the composition of the cleaners
for inclusion into the list of approved compositions.
Response: The EPA believes that the composition
requirements may be applied to any potential cleaning solvent
including those submitted by the commenter. The EPA also
believes that the specifications for the cleaning solvents are
clearly defined and does not believe it is necessary to add
"semi-aqueous" cleaners. Solvent solutions which contain no HAPs
or VOCs are exempt from the hand-wipe cleaning solvent standard.
Comment: Commenter IV-D-11 stated that, while the approved
composition list allows for the use of a wide variety of cleaning
solutions whether solvent-based or aqueous, the proposed rule
needs to have an option to allow the use of cleaners that have
low emission rates that do not fit either of the solution
categories. The commenter suggested that the EPA add this
provision to the final rule.
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Commenter IV-D-42 recommended that enclosed systems for
cleaning be an option to solvent composition requirements.
Response: The EPA does not believe that these options to be
feasible.
Comment-. Commenter IV-D-10 requested the EPA to clarify
whether the rule allows for (1) the use of hand-wipe cleaning
solvents conforming to the composition requirements of Table 3
and (2) the use of any solvent with the only stipulation being
that the vapor pressure of the solvent be below 45 mm Hg?
Response; Paragraph 63.744(b) of the final rule states
that the cleaning solvent solution used in hand-wipe cleaning
operations must meet the composition requirements for approved
cleaning solvents or have a composite vapor pressure of 45 mm Hg
(24.1 in. H:0) or less at 20CC (68CF).
Comment: Commenter IV-D-29 noted that for hydrocarbon-based
solvents, since any HAP emissions will be limited by a 7 mm vapor
pressure requirement, there is no need to further restrict
composition. The commenter pointed out that ozone depleting
compounds will be subject to a ban by the time this rule is in
place. Therefore, the commenter recommended that the composition
requirements for hydrocarbon cleaning solvents be revised by
deleting the last sentence as follows:
"Cleaners that are composed of a mixture of hydrocarbons
and/o_r. oxygenated hydrocarbons and have a maximum vapor
pressure of 7 mm Hg at 20°C (3.75 in. H:0 at 68°F) . These
Commenter IV-D-33 recommended that a HAP and VOC limit
equivalent to the vapor pressure limit also be included. The
commenter believes this change would make it easier for sources
to determine compliance with the proposed rule.
Response: The EPA is satisfied with the composition
requirements for hydrocarbon cleaning solvents. Furthermore, the
final rule specifies different levels of recordkeeping
requirements for 7 mm Hg and 45 mm Hg vapor pressure solvents.
The data collected from the industry indicate that cleaning
solvents are currently being used which contain no HAPs.
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Comment: Commenter IV-D-45 recommended a phased approach to
implementation of the rule. According to the commenter,
incrementally reducing the compliant solvent vapor pressure to
reach 45 mm Hg over a 5-year period after initial enactment of
the rule will allow the additional testing to be completed and
provide the necessary timeframe to insure that adequate
substitutes have been implemented.
Response: Section 112 (i) (3) of the Act specifies that
existing sources are to comply "as expeditiously as practicable,
but in no event later than 3 years after the effective date..."
The EPA believes that compliant solvents are available that will
allow compliance to be achieved, in accordance with this
statutory requirement.
Comment: Commenter IV-D-22 stated that the fact that the
low vapor pressure solvents are not on the HAP list today is not
because they are known to be safer but rather because there was
no impetus to use or develop them for use until the last few
years. According to the commenter, these solvents are not
necessarily safer; they simply have health and environmental
effects that are unknown. The commenter, therefore, was
concerned that the regulation gives the impression that low vapor
pressure solvents are safer, a conclusion for which the commenter
claimed there is no basis.
Response; The EPA does not discuss in the standards or the
supporting information the specific health or environmental
effects of any of the solvents that may be used for cleaning.
However, use of these materials will reduce emissions of and
exposure to hazardous pollutants.
Comment: Commenter IV-D-29 supported the limit of 45 mm Hg
for hand-wipe cleaning solvents. The commenter stated that
§63.744(b) needs to revised to reflect the intent of the rule to
regulate spray gun cleaning through the use of the work practice
standards listed in paragraphs (c)(1)-(c)(4) of this section (and
not just (c) (3)), instead of the vapor pressure controls provided
for in this proposed section. The commenter, therefore,
recommended the following revision to §63.744(b):
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"§63.744(b). gand-wipe cleaning. Each owner or operator of
a new or existing hand-wipe cleaning operation (excluding
hand wipe cleaning of spray gun equipment performed in
accordance with paragraph (c) (3) (c) (l) - (c)_(4) of this
section) subject to this subpart shall use cleaning solvents
that meet one of the requirements specified in paragraph
(b)(1) or (b)(2) of this section."
Response: The EPA accepts this revision because it adds
clarity to the rule, and has revised the rule to reflect the
recommended language.
5.3 SPRAY GUN CLEANING
Comment: Commenter IV-D-42 noted that the proposed rule
[§63.744(b)] specifies vapor pressure limits or a minimum water
percentage for aqueous solvents used for hand-wipe cleaning.
According to the commenter, it is not clear how a low VOC content
solvent fits in with these criteria. The commenter stated that
cleaning solvents with 200 grams or less of VOC per liter of
material have typically been alternatives for these operations.
The commenter suggested that this should be an option for hand-
wipe cleaning.
Response; The EPA believes that the vapor pressure and
aqueous composition requirement sufficiently define the range of
acceptable cleaning solvents. These two parameters effectively
limit the potential to emit without adding additional regulatory
compliance burdens. A facility can freely use a 200 g/liter
solvent if it meets the vapor pressure or aqueous solvent
requirements.
Commeiit: Commenter IV-D-29 believes that the language in
§63.749(c)(1) indicates that hand-wipe cleaning of equipment is
inconsistent with the process of immersing a spray gun in an
enclosed vat. Therefore, the commenter recommended the following
revision:
"(1) Hand-wipe cleaning. The hand-wipe cleaning operation
is considered in compliance with these standards when all
hand-wipe cleaning solvents, excluding those used for hand-
wipe cleaning of spray gun equipment, meet either the
5-13
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composition requirements specified in §63 . 744 (b) (1) or the
vapor pressure requirement specified in §63 . 744 (b) (2) . "
The commenter also stated that they support the work
practice standards put forth in the proposed rule to control
solvent emissions from spray gun cleaning operations and the
determination by the EPA that cleaning methods other than
enclosed gun systems are effective in reducing emissions. The
commenter noted that for "enclosed systems," some over-pressure
can result when solvents are rapidly flushed into an enclosed
container. The commenter stated that many enclosed spray guns
have venting devices as a safety precaution and unless the
regulation specifically allows this device, enforcement personnel
will issue NOV's for the minimal emissions escaping from these
devices .
Commenter IV-D-29 recommended that the phrase "cleaning
shall consist of forcing solvent through the gun with the
atomizing cap in place" be deleted. The commenter believes that
this is not part of the enclosed cleaning system description or
capability. The commenter noted that for "nonatomized" cleaning
of spray guns, the rule requires the atomizing cap to be in
place. The commenter stated that removing the atomizing cap,
however, ensures that the solvent is not atomized. Therefore,
the commenter recommended that §63. 744 (c) (1) (i) and (c) (2) be
revised as follows:
11 (1) (i) Enclosed system. Clean the spray gun in an enclosed
system that is closed at all times except when inserting or
removing the spray gun . The use of a venting device to
prevent pressure build-up inside the enclosed cleaner shall
vJX£a.m.ncf SIIA.J.J. coi^£>x£>t~ OL tiorcx^g SGJ.vsriL
t nirougri tii£ ^jmi witri cri^ &L.c/im.2*xjLig
(2) Nonatomized cleaning. Clean the spray gun by placing
solvent in the pressure pot and forcing it through the gun
with the atomizing cap in place. No atomizing air is to be
used. Direct the solvent from the spray gun into a vat,
drum, or other waste container that is closed when not in
use. "
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Response: The EPA has revised §63.744(c) and §63.749(c)
according to the commenter' s recommendations. The following
sentence has been added to §63.749(c): "Incidental emissions
resulting from the activation of pressure release valves and
vents on enclosed cleaning systems shall not be considered a
violation." In order to minimize the pressure buildup in the
system, the EPA will adopt the commenter's suggestion that the
atomizing cap may be removed prior to cleaning in an enclosed
system. Therefore, "with the atomizing cap in place" has been
deleted from §63.744(c)(1)(i).
Comment: Commenter IV-D-10 stated that, with regard to the
leak determination for spray gun cleaners, the EPA should define
what is considered to be a leak, what is considered to be a
proper seal, and whether the equipment can be tagged out of
service for a longer period of time than 15 days if repair parts
will not be available during that time constraint. The commenter
stated that their experience has been that it is extremely
difficult to find a gasket that will seal the spray gun cleaner
and withstand attack by the solvents utilized.
Commenter IV-D-31 stated that they believe that monthly
inspection of enclosed cleaners will not achieve the EPA's
objective of securing timely repair, unless coupled with an
obligation to repair a detected leak within a determined period.
The commenter recommended that the EPA specify that leaks must be
repaired within 5 days. The commenter also recommended that the
EPA allow sources that elect to inspect every week to have 10
days to complete repairs, since limited extra emissions would
occur with more regular inspection.
Two commenters (IV-D-29, IV-D-35) recommended revisions for
§63.744(c)(1)(ii) as a means of maintaining compliance if repairs
cannot be made within the 15-day period.
Commenter IV-D-29 recommended the following language:
"(ii) If leaks are found during the monthly inspection
required in §63.751(a), then repairs shall be made as soon
as practicable, but no later than 15 days after the leak was
found. If the leak is not repaired bv the 15th dav after
5-15
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detection, ths solvent, shall be removed and the enclosed
cleaner shall be shut down until the enclosed cleaner is
repaired or its use is permanently discontinued."
Commenter IV-D-35 recommended:
"(ii) If leaks are found during the monthly inspection
required in §63.751(a), then repairs shall be made as soon
as practicable. If the leak is not repaired by the
fifteenth day after detection, the solvent shall be removed
and the enclosed cleaner shall be shut down until the
enclosed cleaner is repaired."
Commenter IV-D-30 recommended changing §63.744(c)(1)(ii) to
read as follows:
"If leaks are found during the monthly inspection required
in §63.751(a), spraying may continue as long as repairs are
made as soon as practicable, but no later than 15 days after
the leak was found. After this 15 day period, the leaking
equipment may not be used until the leak is repaired."
Two commenters (IV-D-29, IV-D-35) believe that new language
is needed in §63.749(c)(2) to clarify the EPA's intent with
regard to operating the spray gun cleaner during the 15-day
period after leak discovery. The commenters claimed that their
proposed language allows operators a means of maintaining
compliance if the repairs are not or cannot be made within the
15-day period, and encourages prompt repairs. Commenter IV-D-29
also noted that their proposed language allows for disposal of
equipment which is uneconomical to repair. The commenter
recommended the following revision for §63.749(c)(2)(iii):
"(iii) If an enclosed system is used, monthly visual
inspections are conducted and any leak detected is repaired
within 15 days after detection. If the leak is not repaired
by the fifteenth day after detection, the solvent must be
removed and the enclosed cleaner must be shut down until the
enclosed cleaner is repaired or its use is permanently
discontinued."
Commenter IV-D-35 recommended that §63.749(c)(2)(iii) be
revised to read as follows:
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"If an enclosed system is used, monthly visual inspections
are conducted and any leak detected is repaired after no
longer than 15 days of operation. If the leak is not
repaired by the fifteenth day after detection, t;he solvent
is removed a.nd the enclosed cleaner is shut down until the
enclosed cleaner is repaired or its use is permanently
discontinued."
Response: The EPA has revised §63.744(c)(1)(ii) and §63.749
(c)(2)(iii) so that facilities will have a means of maintaining
compliance if repairs cannot be made within the 15-day period.
Section 63.744(c)(1)(ii) has been revised as follows:
"(ii) If leaks are found during the monthly inspection
required in §63.751(a), repairs shall be made as soon as
practicable, but no later than 15 days after the leak was
found. If the leak is not repaired by the 15th day after
detection, the solvent shall be removed and the enclosed
cleaner shall be shut down until the enclosed cleaner is
repaired or its use is permanently discontinued."
Section 63.749(c) (2) (iii) has been revised as follows:
" (iii) If an enclosed system is used, monthly visual
inspections are conducted and any leak detected is repaired
within 15 days after detection. If the leak is not repaired
by the 15th day after detection, the solvent shall be
removed and the enclosed cleaner shall be shut down until
the enclosed cleaner is repaired or its use is permanently
discontinued."
5.4 FLUSH CLEANING
Commenter: Commenter IV-D-30 understood that §63.744(d)
applies only to flush cleaning of coating application devices and
not to flush cleaning of flight hardware.
Commenter IV-D-29 requested the following change to
§63.744(d) for consistency purposes:
"§63.744(d). Flush cleaning. Each owner or operator of a
flush cleaning operation subject to this subpart (excluding
those in which Table 3 aqueous cleaning solvents are used)
shall empty the used cleaning solvent each time a part,
5-17
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assembly,—or component of a coating unit an aerospace part
or coating equipment (with the exception of spray guns) is
flush cleaned into an enclosed container or collection
system that is kept closed when not in use or into a system
with equivalent emission control."
Commenter IV-D-35 requested the following change to
§63.744(d) for consistency purposes:
"Each owner or operator of a flush cleaning operation
subject to this subpart shall empty the used solvent each
time an aerospace part or coating equipment (with exception
of spray guns) is flush cleaned into an enclosed container
or collection system (that is kept closed when not in use)
or into a system with equivalent emission control."
Response: The EPA accepts the commenters' recommendations
and has adopted the following revision for §63.744(d):
"(d) Flush cleaning. Each owner or operator of a flush
cleaning operation subject to this subpart (excluding those
in which Table 3 aqueous cleaning solvents are used) shall
empty the used cleaning solvent each time an aerospace part
or assembly, or a component of a coating unit (with the
exception of spray guns) is flush cleaned into an enclosed
container or collection system that is kept closed when not
in use or into a system with equivalent emission control."
5.5 EXEMPT OPERATIONS
Comment: Commenter IV-D-28 believes that the EPA's proposed
cleaning solvent composition and vapor pressure requirements may
be impossible for the aircraft glass industry to attain. The
commenter claimed that the chemicals used in the manufacture of
windshields cannot be substituted without months or years of pre-
testing. For these reasons, the commenter requested that
proposed §63.744(e)(10) be revised to include an exemption for
glass substrates and §63.744(e)(11) be clarified to specify that
"associated with production" includes all manufacturing, rework,
reconditioning, or repair operations on aircraft transparencies.
Response: The EPA's intention is to not regulate the
manufacture of aircraft transparencies under this rule.
5-18
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Therefore, the EPA will exempt aircraft transparency
manufacturing in §63.741 Applicability and designation of
affected sources. Specifically, §63.741 (f) has been added to
address exemptions from the NESHAP.
Comment: Commenter IV-D-30 requested clarification
concerning whether cleaning of the interior of the Space Shuttle
System External Tank would be exempt under §63.744(e)(6).
Response: The commenter is correct in assuming that this
particular cleaning operation is exempted from this provision.
Comment: Commenter IV-D-50 stated that the exemption for
cleaning "aircraft fluid systems" should be clarified to include
air-to-air heat exchanges. (The commenter manufactures or
repairs air-to-air heat exchanges.) Although it is clear that
air is a fluid, the commenter desired a clarification that air-
to-air heat exchangers would be included within this exemption.
Response: The EPA accepts this exemption clarification and
has revised §63.744(e)(5) as follows:
"cleaning of aircraft fluid systems that are exposed to the
fluid, including air-to-air heat exchanges;"
Comment: Commenter IV-D-31 expressed concern about the
large categories of operations exempted from the 45 mm Hg
cleaning standard. The commenter stated that the proposal cites
no proof that cleaners with more than 45 mm Hg must be used in
all of these cases. The commenter, therefore, recommended
deleting §63.744(e) exemptions (2), (3), (8), (9), and (10) from
the final rule. The commenter requested a detailed reasoned
explanation, supported by substantial record evidence of all the
exemptions made to this "very basic and excessively modest"
requirement. The commenter also requested that a quantitative
cap be put on any exemptions, sufficient to ensure that these
exemptions remain truly trivial.
Commenter IV-D-34 pointed out that they manufacture two low
vapor pressure solvents that are used at several military
installations for composite repair cleanup. Therefore, the
commenter believes that an exemption should not be provided for
composite repair cleanup. Additionally, the commenter noted that
5-19
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a company in Texas (Lockheed, Fort Worth) uses low vapor pressure
flushing agents. Therefore, the commenter also recommended that
the flushing agent exemption be deleted from the rule.
Several other commenters requested revisions and additional
exemptions. Commenter IV-D-29 noted that proposed §63.744
contains an exemption for cleaning of breathing oxygen systems
((e)(1)) and for cleaning or aircraft fluid systems ((e)(5)) and
believes that these two exemptions should be combined as
suggested in the commenter's November 30, 1993 memorandum to the
EPA.
The commenter stated that it is extremely important that an
exemption be included for hydraulic fluid systems. The commenter
stated that in the past, hydraulic systems ran at relatively low
pressures (2,000 to 4,000 psi), but newer systems run at 4,000 to
6,000 psi. The commenter stated that the cleaning requirements
for the higher pressure systems are much more stringent, as any
residual material left in the lines can reduce or eliminate the
flow of hydraulic fluids through the fine filter frets or the
critically actuated valves.
The commenter recommended the following revision to
§63.744(e):
" (l) Cleaning during the manufacture, assembly,
installation, maintenance, repair, inspection or testing of
components of aircraft fluid and breathing oxygen systems
that are exposed to the breathing oxygen, including the
support systems that interchange fluids with such systems.
Commenter IV-D-30 recommended the following exemptions:
(1) Cleaning during the manufacture, assembly,
installation, testing, maintenance, or repair of components
of oxygen systems that are exposed to the oxygen.
(2) Cleaning during the manufacture, assembly,
installation, testing maintenance, or repair of parts,
subassemblies, or assemblies that are exposed to strong
oxidizers or reducers (e.g., nitrogen tetroxide, liquid or
gaseous oxygen, hydrazine).
(3) Cleaning and surface preparation during the
5-20
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manufacture, assembly, installation, inspection, or testing
of bonding surfaces, tooling interface surfaces, and seal
surfaces and joints."
Commenter IV-D-29 stated that an exemption is necessary for
cleaning in the proximity of aerospace vehicle systems that could
be energized. The commenter pointed out that the Uniform Fire
Code does not allow the use of flammable or combustible liquids
within 5 feet of any energized electrical equipment. According
to the commenter, energized electrical equipment means any item
that is powered by electricity (AC or DC) at such time that the
current could be flowing. The commenter recommended:
\ ^ / L»x e&n .i.rig x)£ iliO^fi.!-!* HXUxO. fiyS L. cIiiD wlicL^ Ciller t?5Cp'wbc\-i i~w
the—fluid Cleaning in the proximity of systems that could be
energized."
The commenter noted that the proposed rule contains an
exemption for cleaning of "limited access spaces" in § (e)(6).
The commenter claimed that limited access is defined by the EPA
in terms of the painting equipment extensions and is not
applicable to cleaning operations. The commenter recommended the
use of "confined spaces" in place of "limited access spaces":
"(6) Cleaning of fuel cells, fuel tanks, and limited access
confined spaces:"
The commenter also recommended the following revision for
exemption (9):
"(9) Cleaning of metallic and non-metallic materials used
in honeycomb cores during the manufacture of these cores,
and cleaning of the completed cores used in the manufacture
of aerospace vehicles or components assembliesr composites
and their topis prior t^p_curef and plastics: "
Commenter IV-D-30 recommended:
"(9) Cleaning of metallic and non-metallic materials used
in honeycomb cores during the manufacture, maintenance and
repair of these cores, and cleaning of the completed cores
used in the manufacture of aerospace vehicles or
components."
Three commenters (IV-D-29, IV-D-30, IV-D-35) believe that
5-21
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the EPA made a typographical error when proposing exemption 11.
The commenters pointed out that the proposed rule would exempt
cleaning operations for "production" and "quality control," as
well as for research, development, and laboratory testing. The
commenters believe that the EPA intended the exemption to be
limited to "production testing" and "quality control testing."
Two commenters (IV-D-29, IV-D-35) recommended the following
revision for §63.744(e)(11):
"(11) Cleaning and solvent usage associated with testing
related to production, research, development, quality
control, and laboratory operations, to include cleaning of
flight or performance simulation articles."
Commenter IV-D-29 believes an exemption is needed for those
cleaning operations that have been identified in an "Essential
Use Waiver" application that has been reviewed and approved by
the EPA, as well as under the International Montreal Protocol.
The commenter noted that Title VI, §604(d)(1) of the Clean Air
Act Amendments of 1990, as well as the Montreal Protocol, allow
waivers for continued production of methyl chloroform (TCA) for
use in essential applications. The commenter stated that Thiokol
Corporation has applied for an Essential Use Waiver to allow the
continued use of methyl chloroform in critical applications on
the redesigned solid rocket motors furnished to NASA for the
Space Shuttle Program, through the year 2000 and that the
Stratospheric Ozone Protection division of the U.S. EPA has
reviewed and approved this application. The commenter also
pointed out that the Air Force is in the process of making a
similar application for the Titan program. The commenter
believes that an additional exemption is necessary so that these
cleaners, as well as any other cleaners approved as "essential,"
can be used.
Based on these comments, the commenter recommended the
following addition to §63.744(e):
"(12) Cleaning operations identified in any Essential Use
Waiver application that has been reviewed and approved by
the U.S. EPA and the voting parties of the International
5-22
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Montreal Protocol committee."
Commenter IV-D-30 recommended:
"(12) Cleaning operations identified in an Essential Use
Waiver application, which has been reviewed and approved by
the U.S. EPA and the voting parties of the international
Montreal Protocol committee. Reference the Clean Air Act
§604(d)(1) , and the applicable parts of the Montreal
Protocol."
Response: The EPA has gathered information from the
industry which indicates that the proposed exemptions are
technically valid. The exemptions granted for specific cleaning
operations allow a facility to use higher vapor pressure solvents
and non-compliant compositions. However, when cleaning solvents
and solutions are used that do not meet the composition
requirements or vapor pressure limits of compliant solvent
solutions, the facility has stricter recordkeeping requirements.
The EPA believes that the current language of §63.744 (e) (5)
which states, "cleaning of aircraft fluid systems that are
exposed to the fluid, including air to air heat exchanges,"
addresses that commenter's concerns pertaining to the exemption
of hydraulic fluids.
The EPA acknowledges that a typographical error was made in
the proposed rule for §63.744 (e) (11) . Section 63.744 (e) (11) has
been revised as follows:
"(11) Cleaning and solvent usage associated with research
and development, quality control, and laboratory testing."
Additionally, the EPA has exempted from the NESHAP the
manufacturing and rework of any aerospace vehicle that has
missions which require the vehicle to escape the earth's
atmosphere. This exemption is addressed under the applicability
section §63.741.
Comment: Coiranenter IV-D-39 noted that the proposed rule
defined "hydrocarbon-based" cleaning solvents as "cleaners that
are composed of a mixture of hydrocarbons and oxygenated
hydrocarbons and have a maximum vapor pressure of 7 mm Hg at 20°C
(3.75 in. H:0 at 68°F). These cleaners also contain no HAP or
5-23
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ozone depleting compounds." The commenter stated that a petition
has been filed to address the photochemical reactivity of
acetone. The commenter remarked that acetone may have specific
uses to the aerospace industry in such areas as surface
preparation for painting. The commenter recommended that the
standard anticipate the possibility that acetone (or other non-
HAP hydrocarbons) may be deemed non-photochemically reactive by
amending the definition of "hydrocarbon-based" as follows:
"Cleaners that are composed of a mixture of photochemically
reactive hydrocarbons and oxygenated hydrocarbons and have a
maximum vapor pressure of 7 mm Hg at 20°C (3.75 in. H:0 at
*
68°F). These cleaners also contain no HAP or ozone
depleting compounds."
Response: The EPA accepts the commenter's recommendation
and has revised §63.744, Table 3. The composition requirement
for hydrocarbon-based cleaning solvents states, "Cleaners that
are composed of a mixture of photochemically reactive
hydrocarbons and oxygenated hydrocarbons and have a maximum vapor
pressure of 7 mm Hg at 20°C (3.75 in. H;0 at 68°F) . These
cleaners also contain no HAP or ozone depleting compounds."
Acetone was added to the list of compounds excluded from the
definition of VOC on the basis that acetone has negligible
photochemical reactivity and does not contribute to ozone
formation. Notice of this exemption was issued June 16, 1995 in
the Federal Register at 60 PR 31633.
5.6 DE MINIMIS EXEMPTION
Comment: Two commenters (IV-D-27, IV-D-50) requested that a
"small quantity exemption" be provided to the solvent
compositions and vapor pressure requirements.
Commenter IV-D-27 recommended that a de minimis value be set
to exempt hand-wipe cleaning from the housekeeping measures.
According to the commenter, if this threshold was not exceeded
per day, the facility would be exempt from these requirements.
The commenter recommended a threshold of 55 gallons per month per
aerospace facility.
Commenter IV-D-50 stated that the cleaning methods they use
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are customer-specifled, and that unlike coating operations,
control equipment cannot be installed to control emissions from
hand-wipe operations. Therefore, the commenter contended that in
instances where a client specifies a non-compliant solvent, they
must refuse the business under the proposed rules. For these
reasons, the commenter recommended that a specified quantity of
solvent be exempted from the solvent vapor pressure and
composition requirements on an annual basis.
Re spores e: There is no technical justification to establish
a low-usage exemption for cleaning solvents. The majority of
emissions from the industry occur from cleaning solvent usage.
Furthermore, the composition requirements for the cleaning
solvents have already been adopted by more than 25 percent of the
industry.
Representatives from the industry have played an integral
part in the crafting of the final rule. The EPA believes that
most of the OEM's have already adapted their hand-wipe cleaning
specifications to the regulations imposed by the California
districts and adopted in the final rule.
5.7 APPLICABILITY UNDER SUBPART GG AND SUBPART T
Comment: Commenter IV-D-49 stated that the EPA has proposed
to regulate work that would be regulated under 40 CFR Part 63,
Subpart T: National Emission Standards for Hazardous Air
Pollutants (NESHAP): Halogenated Solvent Cleaning. The
commenter also noted that the proposed Subpart T regulation,
currently scheduled to be issued in November 1994, is different
in scope from the proposed Subpart GG. The commenter stated that
those facilities using halogenated solvents found on the HAP list
for the purpose of cleaning aerospace components, either during
manufacturing or during rework will be subject to both Subparts T
and GG regulations. The commenter, therefore, recommended that
the halogenated solvents be covered by Subpart T only.
Commenter IV-D-49 stated that the EPA may consider that by
specifying hand-wipe, flush cleaning, and spray gun cleaning of
components (59 FR 29223), it has sufficiently limited the
regulated operations under Subpart GG. The commenter pointed out
5-25
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that, however, flush cleaning and spray gun cleaning could be
defined as cold cleaning machines subject to both Subparts T (the
Halogenated Solvent Cleaning NESHAP) and GG (the Aerospace
Manufacturing and Rework NESHAP), if a halogenated HAP solvent is
used. The commenter referred to the preamble for subpart T,
which states in part:
"...today's proposed regulations for batch cold cleaning
machines are based on the control of carburetor cleaners,
but apply to all cold cleaners using halogenated solvents or
blends" (58 FR 62568).
The commenter also noted that proposed Subpart T defines a cold
cleaning machine as:
"...any device or piece of equipment that contains and uses
solvents in the liquid phase to clean and remove soils from
the surface of materials" (58 FR 62588).
The commenter also suggested that if the hand-wiping is
conducted in a control hood, for the purpose of worker safety,
then the hooded or controlled area could be considered a cold
solvent cleaning machine, and subject to both regulations.
Response: Subpart T places emission limits on cleaning
devices, whereas Subpart GG does not require emission limits for
enclosed cleaning devices. Under Subpart T, facilities are
required to achieve limits specified in the units of kilogram per
hour per square meter of solvent/air interface area. Under
Subpart GG, affected aerospace facilities are required to record
and report the name of the cleaning solvent, HAP content, and
documentation showing the organic HAP constituents of each
cleaning solvent used at the facility. The EPA believes that
Subpart T and Subpart GG do not contain duplicative requirements.
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6.0 PRIMER AND TOPCOAT APPLICATION
6.1 EXEMPTION REQUESTS
6.1.1 Coatings
Coniment: Commenter IV-D-35 requested that the EPA consider
a higher VOC content limit for chemical agent resistant coating
(CARC) topcoat. The commenter suggested that the following
limits be adopted: 530 g/1 when used with conventional air spray
equipment or 550 g/1 (4.6 Ib/gal) when used with electrostatic or
HVLP equipment.
The commenter stated that, although 420 g/1 represents the
MACT floor for most topcoats, MACT has not been demonstrated for
coatings that must meet the special properties of CARC as applied
to aircraft. The commenter pointed out that experience has shown
that in order to avoid cracking on aircraft, the dry film
thickness of the CARC topcoat must be at least 1.8 mils thick and
cannot exceed 2.5 mils.
The commenter stated that in order to achieve the narrow
thickness range with particular emphasis on the maximum limit, it
has been necessary to spray with aircraft green Mil-C-46168
exterior CARC topcoat at 530 g/1 when using conventional air
spray equipment and 550 g/1 when using HVLP equipment.
The commenter stated that DoD usage of CARC for aerospace
applications is approximately 3,500 gallons per year, as
determined from GSA records. The commenter believes that
establishing a limit of 550 g/1 (4.6 Ib/gal), as opposed to 420
g/1 (3.5 Ib/gal) in the proposed rule, would lower VOC and
organic HAP emission reductions by 2 tons per year. The
commenter also pointed out that DoD would avoid spending $131
million for installation of organic emission controls and
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annualized costs of $25.9 million, or $13 million per ton of VOC
emission reduction.
Therefore, the commenter recommended the following additions
to address the concerns stated above:
§63.745(b)(7).
"Organic HAP emissions from Chemical Agent Resistant Coating
(CARC) exterior topcoat shall be limited to an equivalent
organic HAP content of no more than 530 g/1 (4.4 Ib/gal)
when used with conventional air spray equipment and no more
than 550 g/1 (4.6 Ib/gal) when used with electrostatic or
HVLP equipment."
§63.745(b)(8).
"VOC emissions from CARC exterior topcoat shall be limited
to an equivalent VOC content level of no more than 530 g/1
(4.4 Ib/gal) when used with conventional air spray equipment
and no more than 550 g/1 (4.6 Ib/gal) when used with
electrostatic or HVLP equipment."
Response: The EPA has exempted Chemical Agent Resistant
Coating (CARC) from the NESHAP requirements. CARC has been
defined as a specialty coating in §63.742 and the EPA's
recommended VOC limits will be specified in the Aerospace Control
Techniques Guidelines (CTG).
Comment: Two commenters (IV-D-30, IV-D-56) stated that the
Space Shuttle Main Engine and External Tank Projects require a
primer that is specialized in terms of performance requirements
and reliability considerations. The commenters noted that the
exterior of the External Tank is coated with a very specialized
product--DeSoto 515 x 346 epoxy primer. Commenter IV-D-56
pointed out that approximately $600,000 has been spent
investigating alternatives to the currently used cryogenic
flexible primer. According to both commenters, the results of
this investigation showed that the unique technical requirements
of this application have been satisfied to date only by the
current material. The commenters stated that DeSoto 515 x 346
primer has a VOC content of 5.4 pounds per gallon and an
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approximate usage of 1,500 gallons per year based on production
of four tanks per year.
Commenter IV-D-56 stated that the Space Shuttle Main Engine
prime contractor also used this primer to provide cryogenic
corrosion protection and adhesion on critical components and that
an annual usage of 7 gallons per year allows them to adequately
protect the critical areas.
The cryogenic flexible primer cannot be considered in the
flexible primer category because the function of this coating is
quite different. Therefore, the commenter proposed that an
additional category be considered for addition to the aerospace
specialty coating list and proposed the following definition:
"Cryogenic Flexible Primer: A coating designed to provide
corrosion resistance, flexibility and adhesion of subsequent
coating systems when exposed to loads up to and surpassing
the yield point of the substrate at cryogenic temperatures
(-275°F and below). VOC Limit = 5.4 pounds per gallon."
Commenter IV-D-30 requested that the EPA allow use of this
primer in limited quantities for Space Shuttle cryogenic
applications.
Response: The EPA has exempted "cryogenic flexible primer"
from the NESHAP requirements. This primer has been classified as
a specialty coating in §63.742 and will be addressed in the
Aerospace CTG.
Comment: Commenter IV-D-35 recommended the following
addition to §63.745(a):
"The four coating related operations -- adhesives, adhesive
bonding primers, sealants, and specialty coatings are
excluded in this rule."
The commenter noted that the proposed Aerospace NESHAP
contained a broad exclusion from the definition of "primer" or
"topcoat," for specialty coatings that have "additional
performance criteria for specific applications." Additionally,
the commenter suggested that the EPA deliberately decided not to
regulate adhesives, adhesive bonding primers, or sealants, as
noted in the preamble (page 29239).
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The commenter stated that their recommended addition would
clarify the EPA's intent to exclude these coatings from the rule.
Response: The EPA has exempted adhesives, adhesive bonding
primers, and sealants from the NESHAP requirements. These
coatings have been defined as specialty coatings in §63.742 and
will be covered in the Aerospace CTG.
6.1.2 Application Operations
Comment: Commenter IV-D-29 noted that while §63.745(f)(5),
the "inorganic HAP" standard, contains exemptions for operations
that cannot be performed in a booth, there are no exemptions in
paragraph (c) for the same operations that require hard controls
for organic HAP emissions. The commenter claimed that if a
control option is selected because no compliant material is
available that meets the user's requirements, a set of exclusions
for the control requirement is warranted just as it is in the
case of inorganic HAP controls. The commenter recommended that
the following paragraph should be added to the rule to correct
the omission:
"§63.745(c)(3) The following situations are exempt from the
requirements of paragraph (c) of this section:
(jj Painting operations which employ the use of application
techniques that do not atomizg the volatile solvents such as
flow/curtain coat, dip coat, roll coatf brush coat, daub, or
wipe:
(ii) Spray applications to an aerospace vehicle or
component that due to size or other operational
considerations, cannot reasonably be transported to and/or
handled in a booth or hanger: or
(iii) Rework and/or final assembly work of areas that must
be coated out of sequence, subsequent to the normal paint
station process."
Commenter IV-D-30 recommended the addition of the following
paragraph:
"§63.745(c) (3): The following situations are exempt from
the requirements of paragraph (c) of this section:
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(i) Painting operations which employ the use of application
techniques that do not atomize the volatile solvents, such
as flow/curtain coat, dip coat, brush coat, daub, or wipe.
(ii) Spray applications that cannot reasonably be handled
in a booth or hangar where overall capture and control of
81% can be ensured."
Response: The proposal and the final rule contain
exemptions for the control of inorganic HAP emissions from
topcoat and primer operations. The exemptions were intended to
alleviate facilities from implementing controls on operations
which generate or have the potential to generate minimal
emissions.
The final rule does not provide exemptions for facilities
that use control devices to achieve compliance with the organic
HAP emission limit. There is no technical justification for
facilities using a coating than has a HAP content higher than the
limit established in the standard. The use of control devices is
a compliance option, not a requirement. Furthermore, the method
used to apply the coatings does not have any correlation with the
quantity of organic HAP contained in the coating. The fact that
the volatile portion of the coating is not atomized does not
prevent the solvent from evaporating.
As discussed in Section 4, an exemption for out-of-sequence
painting has been included in the final rule. However, an
exemption for vehicles and components that "cannot reasonably be
transported due to operational considerations" has not been
included in the final rule because these concepts are too vague
and unenforceable.
Comment: Commenter IV-D-29 believes an exclusion from
control requirements is needed for sealant detackifying. The
commenter stated that primer is sprayed over fresh sealant to
prevent chips and debris from embedding in the seal, thereby
weakening it after cure, and that application is made primarily
to major assemblies and subassemblies when they are joined and
represents a small quantity of coating. The commenter claimed
that transporting these parts to a booth would not be feasible
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because of the tooling that is required, the large part size, and
the frequency with which this process is carried out. Therefore,
the commenter recommended that paragraph (vii) be added to the
list of exempted operations in §63.745 (f) (5) as follows:
"(vii) Sealant detackifying:"
Response: The EPA has revised the proposed rule on the
basis that potential emissions from sealant detackifying are very
minimal. Section 63.745(f)(5) has been revised to add sealant
detackifying to the list of exempt operations for inorganic
emissions from coating operations.
Comment: Commenter IV-D-35 recommended that the following
be added to the rule:
§63.745(a)(1)
"Aerospace equipment that is no longer operational and is
intended for or on public display is exempt from this
regulation."
The commenter stated that publicly displayed stationary aircraft
require low volume, low frequency applications and cannot be
moved to paint facilities.
Commenter IV-D-29 stated that non-operational aerospace
vehicles such as those intended for public display, which are not
readily mobile and cannot be moved to paint facilities, should be
exempt from the rule. Therefore, the commenter recommended that
paragraph (ix) be added to §63.745(f) (5) as follows:
"(jx) Painting of non-operational aerospace vehicles which
are intended for public display and are not easily Capable
of being moved."
The commenter also recommended that paragraph (vii) be added
to §63.745(e)(2) as follows:
"(vii) Painting of non-operational aerospace vehicles which
are intended for public display and are pot easily capable
of being moved."
Response: The EPA accepts this recommendation since the
standard is not intended to apply to permanent public displays.
Section 63.745(a) has been revised to include the following:
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"Aerospace equipment that is no longer operational, intended
for public display, and not easily capable of being moved is
exempt from the requirements of this section."
Comment; Commenter IV-D-30 stated that with regard to
§63.745(e)(3) and (f)(5)(v) there are applications in certain
Space Shuttle operations that necessitate the use of an airbrush
to apply topcoats in limited access spaces. The commenter
pointed out that these airbrush applications do not strictly
require "an extension on the spray gun" to properly reach the
restricted area nor are the materials applied considered
identification markings. They do, however, require use of an
air-brush to apply very small amounts (a few ounces) of material
to hardware. The commenter suggested modifying §63.745(e)(3)(i)
as follows:
"(e)(3)(i) Any situation that normally requires the use of
an airbrush or an extension on a spray gun to properly reach
limited access spaces."
Response: The EPA accepts the commenter's recommendation
and has revised §63.745(e)(3)(i) accordingly. In addition,
operations and activities that are directly associated with the
Space Shuttle program are exempted from the Aerospace NESHAP.
Comment: Commenter IV-D-29 stated that they support the
exemptions from the application requirements for primers and
topcoats in §63.745(e). The commenter also noted that airbrush
application methods are exempt under SCAQMD Rule 1124 and
recommended that §63.745 (e) (3) (iv) be revised to reflect an
exemption for airbrush application for all uses. The commenter
recommended the following revision:
"(iv) The use of air brush application methods for
*5 I— wijrw -i. -L J-liy f J_
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Comment: Commenter IV-D-28 noted that proposed
§63.744(e)(3) provided that cleaning and surface activation prior
to adhesive bonding is an exempt operation. The commenter stated
that the manufacture of aircraft transparencies involves the
application of solvent based "primers" to glass and interlayer
components to enhance adhesion. The commenter believes that
since the application of "primers" to glass and interlayer
components involves surface activation prior to adhesive bonding,
such operations also should be exempt. Therefore, the commenter
recommended that §63.745 be modified to include an exemption for
cleaning and surface activation operations prior to adhesive
bonding.
Response: The EPA has revised §63.741 to state that the
manufacture and rework of aircraft transparencies is exempt from
the requirements of the NESHAP. Therefore, an individual
exemption under each standard is not needed.
Comment: Three commenters (IV-D-27, IV-D-29, IV-D-30)
requested that aerosol spray cans be exempt from the Aerospace
regulation. Two of the commenters (IV-D-27, IV-D-30) stated that
aerosol can use should be exempt due to the small emission
reductions that would result from their regulation.
Commenter IV-D-29 noted that hand-held spray can
applications are already exempt under SCAQMD Rule 1124. Two of
the commenters (IV-D-27, IV-D-29) stated that the exemption for
spray cans is needed in order to be consistent with the Aerospace
CTG.
Commenter IV-D-27 recommended that §63.745(e)(3)(vi) be
added as follows:
"(vi) - The use of aerosol spray can applications."
Commenter IV-D-29 recommended that paragraph (vi) be added
to §63.745(e)(3) as follows:
"(vi) - The use of hand-held spray can applications:"
Response: The EPA does not intend to regulate the use of
aerosol spray can applications and has revised §63.745(f) (3) by
adding exemption (v) as recommended by the commenters. Section
63.745{f)(3)(v) states:
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"The use of hand-held aerosol spray can application
methods ..."
6.2 DE MINIMIS EXEMPTION RECOMMENDATIONS
Comment -. Commenter IV-D-6 expressed concern that there is
no allowance in the rule for small volume non-compliant coating
use, where small volume usage coatings may be used for research
and development or for other non-specialized small volume use.
According to the commenter, a facility with only minor emissions
of VOC that wanted to use 20 gallons of non-compliant primer or
topcoat would be prohibited from doing so without either the use
of a control device or emissions averaging. A facility that was
a large user of aerospace coatings would be allowed to use the
same 20 gallons of non-compliant coatings, without the use of
controls, if they were able to average them with their compliant
coatings. The commenter stated that VOC emissions from the large
coating user could be much greater than the small coating user,
yet the small user would be prohibited from using the 20 gallons.
The commenter concluded that by not allowing the small volume
exemption, the EPA, in effect, will be penalizing the small
business while only minimally affecting the larger company. The
commenter, therefore, believes that the Aerospace NESHAP should
allow the small volume use of non-compliant primers and topcoats
and recommended modeling the NESHAP after the more conservative
San Diego rule (i.e., 20 gallons per year per separate
formulation with a 50 gallon per year facility cap).
Commenter IV-D-30 claimed that a. great majority of primers
and topcoats are used in quantities of 25 gallons or less
annually. The commenter believes that these small usage coatings
would be cost prohibitive (in most cases) to replace with low VOC
alternates. According to the commenter, a usage allowance of a
total of 300 gallons of non-compliant materials annually per
facility would allow continued use of these limited application
coatings.
Commenter IV-D-48 stated that the State agency provides a
usage exemption within the ARACT that allows the commenter to use
up to 55 gallons per year of any individual coating that does not
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meet the ARACT limitations. Additionally, the ARACT did not
limit the number of non-compliant coatings or place a cumulative
usage limit on the non-compliant coatings that the commenter used
in the course of their business.
Commenter IV-D-29 stated that each of the four California
regulations, which were relied on by the EPA to establish the
MACT floor, contain a de minimis exclusion for coatings (applied
up to a maximum of 200 gallons total at a facility). The
commenter believes that these exclusions set the MACT floor and
thus require the EPA to provide such an exclusion in the
Aerospace NESHAP. The commenter claimed that in calculating the
200 gallon limit in conformity with these California regulations,
other exempt activities (such as research and development, and
use of specialty coatings) should be excluded. The commenter
recommended the following revisions:
§63.745 Standards: Primer and topcoat application
operations.
"(a) Each owner or operator of a new or existing primer or
topcoat application operation subject to this subpart shall
comply with the requirements specified in paragraph (b) of
this section for those coatings that are uncontrolled (no
control device is used to reduce organic HAP emissions from
the operation) and in paragraph (c) of this section for
those coatings that are controlled (organic HAP emissions
from the operation are reduced by the use of a control
device) except as provided below.
(1) Low volume usage: The requirements of this section
shall not apply to the use of non-compliant primers and
topcoats provided that the combined, total of all
noncompliant primers and topcoats at the aerospace facility
does not exceed 200 gallons annually. Exempt primers and
topcoats in paragraphs (e)(3) and f(5) of this section and
in section 63.741(c)(3) shall not be included in the 200
gallon limit."
Response: The EPA accepts the commenter's recommendation
since the California regulations were used as a guideline for the
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development of this NESHAP. Additionally, a large percentage of
affected facilities fall within the California regulations.
Therefore, the EPA has adopted a low-usage exemption in §63.741
for all coating operations. The exemption states that facilities
may use up to 50 gal per separate formulation with a 200 gal
total annual cap on the quantity of noncompliant coating. This
low-volume usage does not include the exemptions contained in
§63.745(f)(3) and (g) (4) and §63 .741(f).
6.3 MACT FLOOR
Comment: Commenter IV-D-12 stated that they currently
require various control techniques for different primer and
topcoat application operations, citing their rule regulating
surface coating and graphic arts. According the commenter, these
rules established RACT requirements in the 1980's and were
supplemented with more categories in May 1994. The commenter
stated that their rule (NJAC 7:27-16.7) allows source operations
to use either compliant coatings with Ib/gal limits, daily
averaging of compliant and uncontrolled non-compliant coatings,
or control devices. Metal parts coating operations using more
than 0.5 gal/hr or 2.5 gal/day must use compliant coatings that
have between 3.0 and 4.3 Ib/gal VOC content or use one of the
other compliance schemes. The commenter pointed out that coating
of assembled aircraft exteriors is exempt from compliance with
the commenter's subchapter 16.
The commenter stated that the MACT standards should be at
least as stringent as these and other States' RACT standards and
that the RACT provisions for metal parts should set the baseline
for this MACT standard.
Response: The EPA is mandated to implement and enforce
standards that are to be applied on a national basis. Since more
than 12 percent of the industry is located in California, the
California regulations were used as a basis for the NESHAP. The
EPA believes that the NESHAP is as stringent as the State
regulations listed above. Also, any regulatory agency is always
free to implement regulations that are more stringent than the
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provisions in the NESHAP, but in no case may any regulatory
agency adopt regulations that are less strict than the NESHAP.
6.4 VOC AND HAP CONTENT OF COATINGS
6.4.1 General Comments
Comment: Commenter IV-D-48 stated that they began
investigating the possibility of using low VOC content coatings
in 1990. On January 1, 1991, the commenter replaced the high VOC
coatings they had been using with low VOC coatings as required
under their ARACT. The commenter pointed out that at the time
their ARACT was developed, certain coatings were not available
with a 3.5 Ib/gal VOC content; however, the State agency,
manufacturers, and the commenter believed that replacement at 3.5
Ib/gal would be available by 1993.
The commenter encountered several problems with the initial
use of the low VOC coatings. The most recurrent problems
included: (1) adhesion; (2) "fish eye"; (3) pitting or wrinkling
in the surface (e.g. "orange peel"); (4) microblistering; (5) and
technical difficulties in the application process. The majority
of the difficulties that were experienced were essentially
eliminated when the manufacturers of the coatings reformulated
the products.
The commenter noted that technical application difficulties
were encountered as a result of the lower solvent content in the
new low VOC coatings and that the application of the low VOC
coatings required different flow rates to accommodate the
different viscosities of the coatings. Once the coating mixture
problems were resolved and the spray guns were set at the
appropriate flow rates, the painters were able to apply the
coatings without any further difficulty.
Commenter IV-D-45 questioned the VOC and HAP limits proposed
for paints and primers. The commenter pointed out that they are
constrained in their choice of materials by the customer's
specifications, and stated that the information they have
received suggests that the proposed VOC and HAP limits are net
necessarily achievable. According to the commenter, there are
few paints and primers available meeting these standards and
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those that are available require scrupulous surface preparation,
often using more solvent for cleaning and generating more
emissions than the higher HAP containing materials would when
considering aggregate emissions from cleaning and coating. In
addition, the commenter claimed that the compliant coatings
proposed require a degree of control not readily available with
hand application and, therefore, these materials may require the
use of sophisticated application equipment (robots) and/or the
use of control technology. The commenter concluded by stating
that for the smaller facilities, the costs for compliance and
achieving the necessary quality requirements are extremely
burdensome.
Commenter IV-D-ll stated that their last 5 years of
permitting experience has indicated that the proposed HAP and VOC
limits of 2.9 Ib/gal for primers and 3.5 Ib/gal for topcoats are
not currently achievable without adversely affecting coating
performance. According to the commenter, one military rework
facility attempted to use low-VOC primers on bombers and
subsequently changed to a higher VOC content coating due to
adhesion problems. The commenter also referred to several
official equipment manufacturer operations in the Dallas-Fort
Worth area who have opted for using add-on control devices in
parts painting since no coating could be found that meets the
current 3.5 Ib VOC/gal limit and achieves the necessary
performance.
Response: The section 114 responses provided comprehensive
VOC content information for all coatings used at each facility
contacted. This information was used to develop a VOC emission
rate (weighted average VOC content) on a pounds of VOC emitted
per gallon of usage basis. The calculation of the VOC emission
rate took into account all types of coatings (e.g., high VOC, low
VOC, higher solids) in use and, where possible, the effectiveness
of control devices.
The VOC and HAP limits established for primers and topcoats
and the approved application methods were derived from
information collected in California. Those sources represent 25
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percent of the industry. Since MACT standards must reflect at
least the average of the best performing 12 percent of sources,
and because the facilities located in California have the lowest
emission rates in the country, the standards as proposed
represent demonstrated technology.
6.4.2 Emission Limits
Comment: Commenter IV-D-29 believes that the EPA has
proposed a standard that does not represent the MACT floor and
that cannot consistently be achieved in practice without
increasing emissions. Although a number of California air
districts have adopted regulations that require primers to meet a
350 g/1 VOC limit, the commenter believes that compliance with
such standards has historically been achieved only through the
use of products that are low-VOC because they contain methyl
chloroform (1,1,1-trichloroethane), a HAP and an ozone depleting
chemical. The commenter claimed that since ozone depleting
chemicals are subject to a ban on production, when methyl
chloroform is removed from the market, compliance by the use of
TCA-based exterior primer to meet the proposed rule's
requirements will no longer be possible.
Commenter IV-D-31 stated that they oppose the "negligibly
reactive compound" exclusion from the VOC content regulations.
The commenter stated that the rule contains no test method by
which to evaluate compliance based on a compound by compound
test. The commenter also stated that some of the emissions
limitations have been justified because stricter emissions
limitations in effect in some places were being met through use
of ozone depleting substances. Yet, according to the commenter,
the exemptions seem to allow these laxer emission limitations to
be met through use of ozone depleters. The commenter stated that
a lack of. reactivity, which is not the same as volatility, may
indicate that a particular VOC is of little concern from a
tropospheric ozone standpoint. However, the commenter concluded,
it does not indicate that it is of no concern from a toxics
standpoint.
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Response: The EPA has collected data which indicates that
87 percent of all emissions regulated by the NESHAP are emitted
from hand-wipe cleaning operations. The EPA has revised the
cleaning operations standard to restrict the use of ODCs. In
addition, 95 percent of all aerospace facilities are located in
nonattainment areas; therefore, these facilities are already
required to monitor their ODC emissions. The EPA believes that
the emissions limits contained in the final rule are easily
attainable by affected facilities since the MACT floor was
developed from information provided by the industry.
Comment: Commenter IV-D-33 supported the approach of
limiting the HAP and VOC content of coatings. According to the
commenter, a source using coatings that meet the applicable HAP
or VOC limitations may still cause a significant public health
impact because of the concentration and quantity of the emissions
and the proximity of residences. The commenter, therefore,
recommended that provisions for establishing source emission
limitations be included. The commenter suggested that one
possible approach would be to allow the implementing agency to
require sources to provide additional information to determine if
a source emission limitation is needed to protect public health.
The commenter offered their assistance to the EPA to develop
appropriate language to be included in the rule.
Commenter IV-D-31 recommended that emission limitations be
more stringent than those currently in effect in California.
According to the commenter, the limitations in section 3-26 of
BID, Volume I are a useful starting place. The commenter claimed
that coatings have been developed that reduce HAP content
substantially in response to these rules.
Response: The EPA has developed the MACT in accordance with
the guidelines established by the Clean Air Act Amendments of
1990. Any local or State agency may adopt regulations that are
more stringent than the NESHAP, but in no case can those
regulations be less stringent than the NESHAP. In addition,
facilities that choose to use averaging to comply with the HAP
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and VOC limits contained in the final rule must include the
averaging plan in their title V permit.
6.5 TOPCOATS
6.5.1 Exterior Commercial Topcoats
Comment: Three commenters (IV-D-14, IV-D-48, IV-D-31)
stated that a separate category with higher limits for commercial
exterior topcoats should not be created. Commenter IV-D-14
stated that alternative operating scenarios are possible to
maintain the lower level of HAP emissions. According to
commenter IV-D-31, the docket contains sufficient information to
show that existing technology allows for the proposed limits to
be met and even exceeded.
According to commenter IV-D-48, the Agency collected data
which established that 12 percent, or more, of the existing
sources subject to the proposed Aerospace NESHAP rule are
currently using exterior commercial topcoats with the HAP and VOC
content levels established in the proposed rule. Consequently,
the commenter concluded that the EPA is precluded from
establishing a separate category and higher HAP and VOC content
levels for exterior topcoats because it would violate the mandate
by Congress requiring the Agency to set the minimum standard at
the MACT floor.
Commenter IV-D-50 stated that the average VOC content of the
topcoats they use has remained well above the proposed topcoat
VOC limits, which supports their view that low VOC coatings for
topcoats on exterior portions of aircrafts are commercially
unavailable. The commenter recommended that a separate category
of higher VOC/HAP limitations be adopted for exterior topcoats.
Commenter IV-D-39 recommended that exterior commercial
topcoats be included within the specialty coatings category in
the proposed CTG. According to the commenter, exterior
commercial topcoats not only represent a very small contribution
to overall emissions, but also provide specialized, high
performance characteristics that cannot be found in the proposed
limits for primers and topcoats. The commenter believes these
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characteristics make it appropriate for treatment as a specialty
coating.
Response: The EPA has collected sufficient data to
determine that the HAP and VOC emission limits are applicable to
exterior commercial topcoats and that the limits can be met by
affected sources. The EPA believes that the record does not
demonstrate a need for segregation of commercial exterior
topcoats into a separate category.
6.5.2 Interior Commercial Topcoats
Comment: Commenter IV-D-52 noted that the proposed rule
contains a single VOC limit for aerospace topcoats. The
commenter pointed out that their Aerospace rule requires that
interior topcoats (i.e. topcoats used in the habitable spaces of
aircraft) meet a more stringent VOC limit of 340 grams/liter (2.8
Ib/gal), unless the coating must meet extreme performance
criteria of fluid, stain, or nicotine resistance. The commenter
believes that interior coatings meeting these more stringent VOC
limits are in common use and may likely define the MACT floor for
these operations.
Response: The EPA has implemented emission limits based on
the data in the record. As discussed previously, any local or
State agency may adopt emission limits that are more stringent
than NESHAP.
6.5.3 Self-Priming Topcoats
Comment: Commenter IV-D-35 stated that existing field
surveys have documented the poor corrosion prevention and
functional fluid resistance properties of chromate-free self-
priming topcoats. The commenter claimed that there are
insufficient data to conclude that self-priming topcoats provide
comparable adhesion and environmental resistance to a
conventional primer/topcoat system. Therefore, the commenter
recommended that the second and third sentences in section
IV.B.I.a(1)(d) of the proposal preamble be revised to read as
follows:
"Self-priming topcoats function as both a primer and a
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topcoat, providing some degree of adhesion, corrosion
prevention, and environmental and functional fluid
resistance. However, the exact nature of these properties
has not been well characterized. These coatings typically
contain reduced amount of chromates relative to conventional
primers."
Response: The industry is free to use many different
coatings on the aircraft in responding to the proposed
requirements. The EPA proposed many options for coating use and
application. Therefore, individual facilities may choose to
select options other than the use of self-priming topcoats based
on their individual experience and requirements. In addition,
self-priming topcoats have been added to the rule as a
subcategory of topcoats. The limits established for self-priming
topcoats are the same as the limits for topcoats in general.
Comment: Commenter IV-D-35 stated that the organic HAP and
VOC content levels allowable for primers and topcoats are
consistent with most of the military's material substitution
efforts (i.e., most of their operations will use compliant
material and will not require equipment for organic emissions
control). The commenter believes that the military will continue
to require the inclusion of certain materials in the list of
specialty coatings. Commenter IV-D-35 stated that the future
development of self-priming topcoat materials to reduce the VOC
and HAP content may not follow the development of either topcoats
or primers.
The commenter, therefore, recommended the following
additions to §63.745:
"(b)(5) Organic HAP emissions from self-priming topcoats
shall be limited to an equivalent organic HAP content level
of no more than 420 grams of organic HAP per liter (3.5
Ibs/gal) of self-priming topcoat (less water) as applied.
(b)(6) VOC emissions from self-priming topcoats shall be
limited to an equivalent VOC content level of no more than
420 grams of VOC per liter (3.5 Ibs/gal) of self-priming
topcoat (less water and exempt solvents) as applied."
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The commenter suggested that the future development of self-
priming topcoat materials which achieve a lower VOC content may
not follow the development of either primers or topcoats.
Response: The EPA has not included water and exempt
solvents in the emission limits for self-priming topcoats.
Section 63.745(c) has been revised as follows:
"(3) ... Organic HAP emissions from self-priming topcoats
shall be limited to an equivalent organic HAP content level
of no more than 420 g/1 (3.5 Ib/gal) of self-priming topcoat
(less water) as applied.
(4) ... VOC emissions from self-priming topcoats shall be
limited to an equivalent VOC content level of no more than
420 g/1 (3.5 Ib/gal) of self-priming topcoat (less water and
exempt solvents) as applied."
6.6 PRIMERS
6.6.1 Flexible Primers
Comment; Two commenters (IV-D-29, IV-D-35) recommended that
the HAP and VOC limits be raised for flexible exterior primers.
Commenter IV-D-35 pointed out that flexible primers are used on
areas of an aircraft where the coating system tends to crack
during flight. The commenters stated that cracks eventually
cause corrosion of the aircraft, which impacts the aircraft's air
worthiness, reliability, and maintenance costs. The commenters
also pointed out that flexible primers are designed to function
as a "bridge" between parts like fasteners, skins, and skin to
skin joints that experience the greatest amount of flex.
Commenter IV-D-35 stated that low VOC flexible primers have
failed field performance tests.
After experiencing problems with corrosion on the F-16, the
commenter (IV-D-35) requested that an extensive study be
conducted to evaluate the corrosion problems of the aircraft.
The ensuing report recommended the use of a primer system, which
consisted of FMS 1058, for adhesion to the steel fasteners, and
FMS 3035 (TT-P-2670), for flexibility. The report also indicated
that the primer system was only critical over the steel fasteners
in the high flex areas of the F-16.
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According to the commenter, when the fasteners in the high
flex areas are primed with the standard flexible primer, 60 to 70
percent of the aircraft is covered. The commenter claimed that
limiting the low VOC coating to the remaining areas results in
low adhesion in the overlap areas. The commenter also claimed
that masking the fastener areas and scuff sanding the overspray
areas produces inconsistent results.
The commenter noted that the depot that maintains the F-16,
prototyped in 1990 both the waterborne and high solids versions
of the low VOC epoxy primer on the F-16 in an attempt to meet
State VOC regulations. The commenter stated that the low VOC
primers were not flexible enough to avoid cracking of the paint
around the fasteners and the manufacturer recommended returning
to the flexible primer. In addition, the commenter noted that
the low VOC flexible primer was also tested on 22 F-16's.
According to the commenter, all aircraft were depainted and
repainted after experiencing failures with the low VOC flexible
prier.
The commenter stated that the DoD's cost to control this
primer with 81 percent VOC removal would equate to $1.7
million/ton, which is based upon $11.5 million annualized cost of
controls.
The commenter also stated that the performance of high
solids flexible primers has been inconsistent, even though some
products are qualified to the Federal specification. The
commenter stated that most of their facilities have experienced
problems applying the primer at the recommended thickness. The
commenter also noted that adhesion problems occurred on many
aircraft.
The commenter stated that the use of flexible primer is
essential to the military on several types of aircraft. Without
the use of the flexible primer, there will be a higher incidence
of paint failures and corrosion, as indicated by records of
failures prior to the use of flexible primer on those systems.
Both commenters (IV-D-29, IV-D-35) suggested that, if the
EPA decides not to regulate flexible primers as a specialty
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coating category under the CTG, the Agency should allow for a
higher limit within the NESHAP commensurate with the established
MACT floor of 640 grams per liter for VOC and organic HAP.
Commenter IV-D-29 understood that at present, flexible
primer is considered a "specialty coating" because its uses are
specialized and because the EPA background studies to establish
the MACT floor did not address it. For these reasons alone, the
commenter claimed that the EPA could not regulate flexible
primers without issuing a supplemental proposal for comment.
Commenter IV-D-25 recommended the following revisions with
respect to flexible primers:
Add to §63.742:
"Flexible primer - A coating that meets flexibility
requirements such as those needed for adhesive bond primed
fastener heads or on surfaces expected to contain fuel."
Add to §63.745:
"(a) Organic HAP emissions from flexible primers shall be
limited to an equivalent organic HAP content level of no
more than 640 grams of organic HAP per liter of flexible
primer (less water) as applied."
Add to §63.745:
"(b) VOC emissions from flexible primers shall be limited
to an equivalent VOC content level of no more than 640 grams
of VOC per liter of flexible primer (less water and exempt
solvents) as applied."
Response: The EPA has exempted flexible primers from the
NESHAP requirements. "Flexible primer" has been defined as a
specialty coating in §63.742 and will be addressed in the CTG.
6.6.2 Commercial Exterior Primers
Comment -. Commenter IV-D-31 suggested that commercial
exterior primers should have a minimum emission limit of 340 g/1.
The commenter claimed that several military sources already meet
this limitation. According to the commenter, the record fails to
demonstrate that commercial aviation has any physical
characteristics that make application of the primers meeting this
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specification impossible. With respect to primer, the commenter
claimed that the military has approved sources at 340 g/1.
Specifically, the commenter stated that the record
demonstrates that the following emission limitations are
achievable, based on products either approved or in the process
of being approved:
antichafe:
3.5 Ib/gal
(Mil-C-85285, Type I)
clear:
3.5 (Mil-C-85285, Type I)
epoxy polyamide topcoat:
3.5 (Mil-C-53022)
flexible primer:
2.8 (TTP-2756)
metalized epoxy-zinc filled: 2.0 (Mil-P-26915 C)
(this has been approved
recently)
optical antireflection: 3.5 (Mil-C-46168 and
Mil-C-85285 Type I)
fuel Tank:
3.5
rain erosion resistant:
3.5
wing:
3.5
elevated skydrol resistant primer: 340 grams per liter,
(approved coatings include 44-GN-57 (McDonnel Douglas
approved, 44-GN-ll and 44 GN-60 (approved to BMS 10-11 Type
1) .
Commenter IV-D-29 stated that their experience under the
California regulations indicates that compliance with the
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proposed EPA control levels is not possible for all commercial
aircraft. The commenter claimed that California sales figures
from one of the major suppliers of exterior primer, provided to
the EPA, show that essentially all the material (25,000 gallons)
supplied in 1993 was a high HAP-containing material containing
methyl chloroform produced specifically to meet local regulatory
limits on VOC. The commenter also claimed that only a limited
amount of high solids exterior primer has been sold in California
to date. The commenter claimed that several companies have
concluded that high solids exterior primer is very sensitive to
the degree of surface cleanliness. The commenter stated that
current cleaning techniques have difficulty removing all of the
contaminants (silicone oils in particular) from the surface prior
to priming, even if additional hand-wipe cleaning is employed
with attendant emissions. According to the commenter,
conventional primers tend to absorb these contaminants, providing
a priming surface that is acceptable for topcoat adhesion and
appearance. High solids primers fail to adequately absorb these
low levels of surface contamination, resulting in rework to
ensure that the required primer thickness is attained.
The commenter stated that one OEM developed a set of
scenarios, provided to the EPA, which explored the emissions
resulting from several different cleaning/painting schemes. The
commenter claimed that on the 10 aircraft studied, rework
resulted in 75-200 pounds of additional emissions per aircraft,
which is only partially offset by the 25 pound reduction due to
the use of the primer itself.
The commenter claimed that this OEM used only the high
solids exterior primer on the fuselage. According to two
commenters (IV-D-29, IV-D-40), other exterior primers are used on
the wings, the horizontal stabilizers, the vertical fins, the
fairings, the nonmetallic (composite) doors, struts, and other
exterior surfaces. Commenter IV-D-29 stated that these primers
are usually applied at the detail part or subassembly stage and
have even more stringent erosion/corrosion requirements than the
fuselage primers.
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Commenter IV-D-40 claimed that this is largely because the
fuselage is stripped and repainted at frequent intervals,
allowing for inspection and corrosion repair, while the wings,
stabilizers, and similar parts are not.
Commenter IV-D-29 added that wings and struts have extreme
corrosion design requirements and must be more flexible than the
fuselage primer. Two commenters (IV-D-29, IV-D-40) pointed out
that none of the low-VOC candidate materials for this application
have successfully met the requirements. Two commenters (IV-D-29,
IV-D-88) stated that composite parts such as wing-to-body farings
and landing gear doors (there are many others) are painted with a
nonchromated version of the wing primer to reduce chromium
emissions for both environmental and worker safety reasons.
Commenter IV-D-88 is using a 650 grams/liter primer for this
application operation. Commenter IV-D-88 is concerned about the
level of solvents required to rework the aircraft with the 350
grams/liter coating in its current formulation. In addition to
these increased VOC emissins, the commenter is concerned that the
sanding and general rework increases their workers potential
exposure to chromated material. Commenter IV-D-29 stated that
several low VOC/HAP versions of this primer have been tested, but
none has met engineering requirements. The commenter pointed out
that the MACT designation for these materials must represent the
available technology in use.
Commenter IV-D-88 painted the fuselage of 24 aircraft with
two versions of a low-VOC commercial exterior primer produced by
Crown Metro. The commenter stated that their best application
results required an estimated 20 percent rework and use of
additional solvent. Of the 24 aircraft the commenter painted, a
conventional 650 grams/liter primer was used on the wings of all
but the first 3 of these aircraft. The commenter stated that
after their initial attempts to use the low-VOC, high-solids
primer on the wing surfaces, both they and their customers who
had requested the primer agreed that the primer did not work in
this application.
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The commenter clarified in a later letter that wings require
special coatings due to the increased durability and corrosion
resistance. The commenter pointed out that selected areas of the
wings are assembled and coated with primer and wing coating on
the factory floor prior to being attached to fuselages. The
commenter noted that the aircraft is then delivered to the paint
hangar to recieve a topcoat on the wing. The commenter stated
that they tried the low VOC topcoat over the wing coating and had
failures. The commenter also stated that due to the use of high
temperature silicon sealants in the vicinity of the engines and
the lubricants used on the many complex moving parts on the wing,
the wing surface area is often covered with contaminants prior to
the coating operation. The commenter claimed that the solvent
based coatings will readily adhere to the contaminated surface
whereas the low VOC coatings will not adhere requiring extensive
rework.
The commenter is using another 650 grams/liter primer on
certain limited areas of the aircraft; wing to body fairings,
landing gear doors, and other composite parts. The commenter is
using this primer because it is nonchromated and eliminates
worker exposure to chrome. The commenter noted that they have
not received any promising low VOC candidates to replace this
product to date.
Commenter IV-D-40 estimated that all commercial exterior
primers used on exterior surfaces represent only 20 percent of
primer usage. Further, most of that material, 15 percent of all
primer, is used on the metal fuselage. The commenter also added
that only 5 percent of all primer is used on the wings,
composites, and other surfaces. Commenter IV-D-88 estimated that
last year they used approximately 36,000 gallons of exterior
primer. The commenter noted that 8,000 gallons, or approximately
22 percent of the exterior primer, was used on wings.
Commenter IV-D-40 recommended that the Agency consider more
feasible alternatives to the VOC/HAP content requirements for
exterior primers.
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Commenter IV-D-88 believes that adding 2 years to the
compliance period would allow more time for the development of an
alternative for the fuselage application reducing VOC emissions
overall, rather that simply trading reduced VOC coating levels
for additional solvent VOCs to rework the coating on the
aircraft.
Commenter IV-D-90 believes that their operations show that
the proposed organic HAP and VOC content limit standards for
commercial exterior primers are representative of demonstrated
technology so that there is no need to modify the proposed
organic HAP and VOC content limits of 2.9 Ib/gal.
The commenter does not believe that a separate source
category should be created with a higher organic HAP and VOC
content level for commercial exterior primers (or topcoats).
The commenter pointed out that there has been no explanation of
how the proposed standard does not represent demonstrated
technology. The commenter noted that they are currently using
low organic HAP and VOC content level primers at or below the
proposed standard. The commenter also noted that the EPA has
already collected data which indicated that 12 percent or more of
existing sources meet the proposed limit. The commenter believes
that there must be a factual basis to establish subcategories for
commercial exterior primers. The commenter believes that the
source that raised the objection to the proposed limit should
demonstrate why it cannot use the primers and techniques used by
the commenter and others that conform to the proposed standard.
The commenter stated that the likelihood that the source would
state why they cannot comply is doubtful because according to the
commenter, there are only three principal manufacturers of
commercial aircraft and the commenter uses its low organic HAP
and VOC content level primers on all three (Boeing, McDonnell
Douglas, and Airbus).
Response: The EPA received specific comments and technical
justification from one company as to why they cannot comply with
the emission limits. The EPA will work with that company to
derive a mutually beneficial conclusion to their dilemna.
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The information received by the EPA indicates that all other
affected facilties can comply with the limits specified in the
final rule.
6.7 PROPOSED APPLICATION METHODS
Comment: Commenter IV-D-35 recommended that the EPA
reconsider adding to its list of acceptable coating methods
"conventional spray equipment." The commenter believes that
conventional spray equipment represents the "MACT floor" as well
as any other technology. According to the commenter, as HVLP and
other technologies mature they may accurately produce the claimed
results of greater transfer efficiency, but for now industry
requires the use of proven technology to perform its services at
the highest standard.
The commenter agrees that HVLP has had admirable results in
the laboratory in small scale testing, but according to the
commenter HVLP's results in production tests are inconclusive at
best. Removing conventional spray equipment from the approved
coating application list at this time would be an unwise and
imprudent move on the part of the EPA. The commenter believes
that it is more appropriate for the EPA to monitor the progress
the aerospace industry is making for a while longer before making
such an important decision.
Commenter IV-D-29 stated that they conducted an informal
survey of industry members in response to the EPA'S request for
comments regarding the labor-hours per gallon of coating applied
for HVLP spray guns versus conventional spray guns, and found
that the use of HVLP spray was not believed to save time or money
over conventional guns. The commenter stated that one user
estimated that for actual spraying time (not including support),
HVLP coating took 0.04 hr/gal longer to apply as compared to
conventional spray guns [0.24 hr/gal (HVLP) vs. 0.20 hr/gal
(conventional)]. The commenter believes that the coating
material savings are small and when support and rework costs are
included, the application cost of HVLP is significantly higher.
Response: All of the California facilities located in
nonattainment areas use HVLP, electrostatic spray, or high
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transfer application methods for coatings to reduce the
emissions. As stated earlier, these facilities represent 25
percent of the industry. Additionally, these facilities have
maintained economic viability, even though their standards are
more stringent than other areas around the country. The EPA
believes that these application methods will lead to a reduction
in HAP emissions without imposing a significant burden on
industry.
Comment: Commenter IV-D-29 recommended that
electrodeposition of organic coatings be listed in the rule as an
acceptable application procedure. The commenter
recommended that paragraph (vii) be added to §63.745(e)(l) as
follows:
"(vii) Electrodeposition;"
Commenter IV-D-29 also noted that a flow coat application is
often referred to as flow "curtain" application. The commenter
pointed out that the coating may take the form of a narrow,
focused stream; a wide, less focused stream; or a wide, but thin,
"curtain" of fluid. In each case, the commenter stated that the
coating is not atomized and transfer efficiency is essentially
100 percent. The commenter recommended that the language in
§63.745 be revised to reflect this fact. Therefore, the
commenter recommended that §63.745 (e)(1)(ii) be revised as
follows:
"(ii) Flow/curtajn coat application;"
Commenter IV-D-29 also stated that there is a need to allow
for "daub and wipe" applications. According to the commenter,
certain operations, such as fastener installation, require that
primers or topcoats be applied using a cotton-tipped dauber,
swab, or cloth. Therefore, the commenter recommended that
paragraph (viii) be added to §63.745(e)(1) as follows:
"(viii) Daub and wipe applications; or"
Response: The EPA accepts cotton-tipped swab application
and electrodeposition application as acceptable coating
techniques since the emissions from these techniques would be
minimal when compared to conventional spray equipment. The
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following have been added to §63.745 (f)(1) as acceptable
application methods:
"(v) Cotton-tipped swab application;
(vi) Electrodeposition (dip) coating;"
The EPA has also revised §63.745 (f)(1) (i) as follows:
11 (i) Flow/curtain coat application;"
Comment: Commenter IV-D-30 stated that a great deal of
research is underway, by government and industry alike, to
develop environmentally friendly coating systems. The commenter
suggested that the language of the rule be modified to facilitate
the implementation of emerging technologies. According to the
commenter, these newer technologies should not be required to use
high-transfer efficiency methods or other emission controls.
Commenter IV-D-11 believes that, while there are other spray
application technologies (airless and air-assisted airless), a
sufficient number of spray application technologies have been
proposed to allow industry a great deal of flexibility.
Response: The EPA believes that a sufficient number of
application options have been offered. Additionally, any
facility may use an alternative application technique that
achieves emission rates equivalent to HVLP or electrostatic spray
application techniques (§63.750(i)).
Comment: Commenter IV-D-35 recommended that §63.745(e) be
revised as follows:
"Application Equipment. Except as provided in paragraph
(e)(3) of this section, each owner or operator of a new or
existing primer or topcoat application operation subject to
this subpart in which any of the coatings contain HAP or VQC
shall comply with the requirements specified in paragraphs
(e)(1) through (e)(3) of this section."
Response: The EPA's intention is to mandate only VOC and
HAP emission controls. Therefore, the commenter's recommendation
has been incorporated into the final rule (§63.745(f)).
6.8 ALTERNATIVE APPLICATION METHODS
Comment: Commenter IV-D-23 noted that the proposed rule
indicates that any facility wishing to use an alternative
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application method for primers and topcoats must first determine
initial emission levels using HVLP or electrostatic spray
application. According to the commenter, the preamble could be
construed to mean that this determination must be made under
actual production conditions, which would require the facility to
coat parts using both the proposed alternative application method
and HVLP or electrostatic spray application. If the intent is to
only require that the alternate method be tested under actual
production conditions, this should be more plainly indicated in
the final rule. The commenter recommended that the EPA clarify
this requirement and be more specific about how facilities must
determine and/or demonstrate alternative methods.
Response: The rule clearly states that actual production
conditions will be used to make the determination. Section
63.750 (i) (2) (ii) states:
"Upon implementation of the alternative application method,
use the alternative application method in production on
actual production parts..."
6.9 TOUCH-UP AND REPAIR APPLICATION OPERATIONS
Comment: Two commenters (IV-D-16, IV-D-35) noted that the
proposed rule limits the amount of touch-up and repair painting
to no more than 4 square feet per aerospace vehicle, regardless
of vehicle size. The commenters stated that 4 square feet is
insufficient, under any circumstances, to cover this type of
painting operation. Commenter IV-D-35 stated that the proposed
NESHAP fails to reach an adequate balance between national
security and environmental quality.
Commenter IV-D-35 stated that overhaul and repair operations
are called "maintenance painting" and are inappropriately given
the same MACT standards as full aircraft primer and topcoat
applications. The commenter stated that maintenance painting
means painting operations after non-destructive inspection (NDI),
corrosion rework, composite replacement, metal panel replacement,
aircraft modification, panel access, or other maintenance
activities to insure aircraft structural integrity. The
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commenter pointed out that the proposed rule does not recognize
or distinguish this type of painting.
The commenter suggested that maintenance painting is an
important maintenance tool for ensuring both airworthiness and
operational readiness of aerospace vehicles. Commenter IV-D-37
pointed out that Airworthiness Directives ("AD's") issued by the
Federal Aviation Administration may mandate, for purposes of
aviation safety, that aircraft components or systems be
inspected, replaced, or repaired on a time-critical basis. The
commenter claimed that compliance with AD's may necessitate the
stripping and repainting of various sections of the aircraft
under time constraints that potentially could not be accomplished
fully in accordance with the control provisions of the proposed
NESHAP. The commenter concurred with AIA's recommendation that
an exclusion for permissible maintenance painting limited to 10
percent of the exterior surface of an aerospace vehicle per year
would constitute a reasonable and adequate control mechanism.
The commenter, therefore, recommended that the proposed MACT
standards for controlling inorganic HAP emissions from primer and
topcoat applications should not be applied to maintenance
painting. Since maintenance painting operations were not
analyzed during the development of the proposed NESHAP, there is
no basis for establishing a MACT floor, other than no control.
The commenter stated that touch-up and repair painting
supports aircraft aesthetic repairs and coating system longevity
on the outer mold line of the aircraft, while maintenance
painting supports aircraft structural integrity during aircraft
overhaul and repair operations.
According to commenter IV-D-35, touch-up and repair painting
can potentially be accomplished in a paint hangar or booth with
emission controls (the aircraft is mobile); however, most
locations where aircraft are stationed do not have a paint hanger
(80 percent estimate for DoD), and touch-up and repair painting
is typically "out of cycle" or non-scheduled painting. The
commenter claimed that because emission controlled hangars have
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low availability (fully scheduled), it is difficult to schedule
out-of-cycle touch-up and repair operations. Therefore, the
commenter pointed out that touch-up and repair is usually
accomplished in facilities without emission controls.
Commenter IV-D-35 believes that the 4 square feet exemption
is an arbitrary limitation that ignores the range in aircraft
size from 500 square feet to 33,600 square feet. Commenter
IV-D-16 noted that 135 ft2 equals 1 percent surface area on the
larger planes in the U.S. Air Force fleet.
The commenter conducted a survey of 28 operational field
activities and 4 major maintenance depots within the Air Force,
to gather information on maintenance painting and touch-up and
repair painting operations. The commenter presented the survey
information on maintenance painting and touch-up and repair
painting combined, including number of aircraft, gallons painted
per year, area painted per year, and area of aircraft assigned
(field units) or serviced (depots). Calculated values were shown
for square feet of coverage per gallon of paint, square feet of
aircraft assigned (or serviced) per gallon of paint, square feet
painted per aircraft assigned, and gallons applied per aircraft
assigned. On average, the commenter suggested that an exemption
of 619 square feet per aircraft is needed. The requirement
varies from 75 square feet/year (0.18 gal/yr) for a T-37 with 780
square feet of exterior surface area to 3,208 square feet/year
(7.6 gal/yr) for a C-5 with 33,600 square feet of exterior
surface area. The commenter pointed out that the survey
demonstrated the problem associated with establishing a single
square footage or gallon limit for painting exemptions. The
commenter believes a better approach would be to exempt a number
of gallons per thousand square feet of aircraft assigned or
serviced. The commenter stated that this approach accounts for
variations in size, and it allows a facility to easily determine
and control its allotment of exempt painting (through a pharmacy
or other distribution control system). The commenter determined,
based on the data, that approximately 0.32 gal/1,000 ft" for
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depots and 0.19 gal/1,000 ft2 for field units would be
appropriate exemptions.
According to the commenter, due to the significant need for
maintenance painting in support of aircraft structural integrity
efforts, the Aerospace NESHAP needs to be modified to allow
maintenance painting in overhaul and repair hangers with no
forced ventilation or emission controls using spray application
of paints containing inorganic HAP.
The commenter, therefore, recommended that the following
definition be added to §63.742:
"Maintenance painting means painting operations after non-
destructive inspection (NDI), corrosion rework, composite
replacement, metal panel replacement, aircraft modification,
panel access, or other maintenance activities to insure
aircraft structural integrity."
The commenter recommended that the definition for "touch-up
and repair operation" be revised as follows:
"Touch-up and repair operation means that portion of the
coating operation that is incidental to the main coating
process and is used to cover minor imperfections in the
coating finish. Touch up and repair operations are not to
exceed four square feet-per aerospace vehicle."
To exempt maintenance painting and touch-up and repair
painting from the inorganic HAP emission requirements of
§63.745 (f) (1) through (f) (4) and to limit the exemption, the
commenter recommended that the following paragraph be added as
§63.745 (f) (6) :
"Maintenance painting and touch-up and repair painting are
exempt from paragraphs {f)(1) through (f)(4) of this
section. The volume of exempt maintenance painting and
touch-up and repair painting is limited to 0.33 gallons per
thousand square feet of aerospace vehicle assigned or
serviced on an annual average basis."
The commenter also recommended that the following paragraph
be added as §63.749 (e) (3) for the compliance determination
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associated with maintenance painting and touch-up and repair
painting:
"The total gallons of inorganic HAP containing primer and
topcoat used for maintenance painting and touch-up and
repair painting is less than MPG, as determined using the
procedures specified in §63.750(X)."
To ensure procedures for establishing exempt gallons for
maintenance painting and touch-up and repair painting, the
commenter recommended the following addition to §63.750:
"(X) Exempt gallons for maintenance painting and touch-up
and repair painting. Calculate the gallon limit for exempt
painting using the following equation:
n
MPG = £ A/, x GALi
1=1
where
Nx = the number of aircraft of type i assigned or
serviced during the year
GAL. = gallons per aircraft type determined by dividing
the total aircraft exterior surface area by 1000
square feet and multiplying the answer times 0.33
gallons (0.33 gallons/thousand square feet
exemption)
n = number of distinct aircraft type assigned or
serviced."
Response: The EPA believes that the commenters'
recommendations with respect to "maintenance painting" are too
broadly defined and would encompass many of the activities the
EPA intends to regulate. The commenters1 recommendation could be
interpreted to mean any rework activity. Therefore, the EPA will
not add the recommended definition to the rule or exempt
maintenance painting from the rule.
The EPA does, however, accept the commenters1 recommendation
that the 4 square feet per aerospace vehicle touch-up exemption
be deleted. The EPA is not defining a size limitation on the
touch-up repair operation, but will allow the permitting agencies
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to define that parameter. The EPA has revised the definition as
follows:
"Touch-up and repair operation means that portion of the
coating operation that is the incidental application of
coating used to cover minor imperfections in the coating
finish or to achieve complete coverage. This definition
includes out-of-sequence coating." The EPA has added out-
of-sequence coating to the definition to allow facilities to
use any type of application method for this type of
operation. This addition does not, however, allow the
facility to freely use the touch-up and repair operation
exemption to recoat an entire aircraft on the flightline
without using controls. The exemption was incorporated in
the rule to allow facilities to apply coating to small areas
(4 ft2 in the proposal) of the aircraft without being
constrained to a particular type of application method. The
EPA understands that 4 ft2 is not adequate for some of the
larger aircraft and will allow the permitting authority to
determine what constitutes a touch-up and repair operation."
6.10 OPERATION AND MAINTENANCE OF APPLICATION EQUIPMENT
Comment: Three commenters (IV-D-27, IV-D-29, IV-D-35)
stated that there are cases in which existing or new process
equipment has inadequate, inaccurate, or incomplete operating
instructions. In such cases, the commenters stated that the user
must develop additional instructions to ensure proper operation
and compliance with safety and environmental laws. In addition,
a company may modify a purchased spray gun or develop its own
equipment. According to two of the commenters (IV-D-27,
IV-D-29), the provision should be changed to accommodate cases
where modified equipment operated per the company's documentation
has proven to have equivalent transfer efficiency, or when a
company has identified alternative specifications that are
optimal for a given application. Commenter IV-D-27 pointed out
that the environmental benefit should be the same since the
process is still bound by the VOC/HAP limitations or the control
requirements.
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Commenter IV-D-27 recommended the following revisions for
§63.745(6)(2):
"(2) All application devices used to apply primers or
topcoats shall be operated according to company and or the
manufacturer's specifications at all times."
Commenter IV-D-29 recommended that §63.745(e)(2) be revised
and paragraph (i) be added as follows:
"All application devices used to apply primers, topcoats, oj:
self-priming topcoat shall be operated according to the
manufacturer's specifications or local specified operating
procedures."
Commenter IV-D-35 recommended that §63.749(d)(3)(iv) be
revised to read as follows:
"Operate all application techniques in accordance with the
manufacturers' specifications or local specified operating
procedures."
The commenter also recommended the following revision for
§63.749(d)(4)(iv):
"Operate all application techniques in accordance with the
manufacturers' specifications or local specified operating
procedures."
The commenter suggested that in many cases existing or new
process equipment have inadequate or incomplete operating
instructions which require additional instructions to ensure
proper operations and compliance with safety and environmental
laws.
Response: The EPA accepts the commenter's recommendations
and will allow companies to implement their own operational plans
for equipment that has been modified or developed by the company.
The modified equipment must achieve an equivalent transfer
efficiency to HVLP or electrostatic application techniques. In
no case may company modified or company developed application
equipment be used where the transfer efficiency is less that the
results achieved by HVLP or electrostatic application techniques.
The EPA has adopted the following revisions for §63.745 (f) (2):
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"All application devices used to apply primers or topcoats
shall be operated according to company procedures, local
specified operating procedures, and/or the manufacturer's
specifications, whichever is most stringent, at all times.
Equipment modified by the facility shall maintain a transfer
efficiency equivalent to HVLP and electrostatic spray
application techniques."
Section 63.749(d)(3)(iv) has been revised as follows:
"Operates all application techniques in accordance with the
manufacturer's specifications or locally prepared operating
procedures, whichever is more stringent."
The following revision has been adopted for section
63.749(d)(4)(iv):
"Operates all application techniques in accordance with the
manufacturer's specifications or locally prepared operating
procedures, whichever is more stringent."
Additionally, §63.743(b) requires a facility to report the
startup and shutdown, and operational procedures that are
followed when a facility varies from the procedures specified by
the equipment manufacturer.
6.11 AVERAGING BETWEEN TOPCOATS AND PRIMERS, CONTROLLED AND
UNCONTROLLED
Comment: Three commenters (IV-D-29, IV-D-33, IV-D-43) noted
that the proposed regulation prohibits averaging between primers
and topcoats. According to commenter IV-D-43, even though the
majority of coatings used will meet or exceed the VOC or HAP
limit stated in the regulation, a few facilities may require
emissions averaging in order to demonstrate compliance. The
commenter stated that their future VOC emissions reduction
programs will depend on providing flexibility, such as averaging
between primers and topcoats. Two of the commenters (IV-D-33,
IV-D-43) recommended that the EPA allow averaging between primers
and topcoats and that the EPA grant the State and local agencies
the discretion to allow or to preclude sources from emissions
averaging without having to make a section 112(1) rule approval
request. Commenter IV-D-29 believes that the ability to average
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such emissions will encourage the industry to develop lower
VOC/HAP coatings and processes in order to take advantage of
emissions averaging as the need arises.
Commenter IV-D-33 suggested that, if averaging is allowed,
the following provisions should also apply:
1) The sources who elect to use averaging must demonstrate
to the satisfaction of the implementing agency that
compliance through averaging will not result in greater
hazard or risk than compliance without averaging.
2) The implementing agency should be allowed to limit the
number of emission points or coatings allowed under
averaging.
3) State and local agencies should be granted the
discretion to preclude sources from using emissions
averaging to comply with the rule without having to
make a section 112(1) rule approval request.
Commenter IV-D-50 suggested that the 1-day averaging
requirement for a coating may, in effect, greatly exceed the MACT
floor. The commenter noted that the rule summary stated that the
VOC/HAP limit was based on the average emissions of the best 12
percent of the sources. The commenter pointed out that it was
not reported over what time period the emissions from these
sources were averaged to obtain the VOC/HAP limits. According to
the commenter, if a greater time period than 1 day was used, then
the proposed limits are far stricter than the MACT floor. The
commenter recommended that the proposed averaging include a time
period at least as long as that upon which the coating
limitations were calculated for the best 12 percent of the
sources.
Response: The information collected by the EPA indicates
that separate levels of emission control are needed for topcoats
and primers. In no case may emissions averaging be used between
topcoats and primers since different levels of emissions control
are required for each. Averaging of topcoats or averaging of
primers is a compliance option. Facilities do not have to use
emissions averaging. Facilities that use compliant coatings and
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compliant application methods will not have to use averaging and
or control devices in order to be in compliance.
The EPA has revised the averaging period from daily to
monthly. Therefore, the volume-weighted average mass of organic
HAP emitted per volume of coating must be calculated on a monthly
basis. However, the permitting agency may require a shorter
averaging period as part of an ambient ozone control program.
In addition, the EPA is currently investigating a number of
options with respect to implementing a broad-based averaging
scheme as a compliance option for the Aerospace NESHAP. The EPA
will issue a supplemental proposal to the NESHAP that will
solicit public comments on an expanded averaging plan (see
Section 2.2).
Comment; Two commenters (IV-D-27, IV-D-29) recommended that
averaging be allowed between uncontrolled and controlled
coatings.
According to commenter IV-D-29, the EPA could actually gain
an environmental benefit if it allowed emissions averaging
between controlled and uncontrolled sources if it required
offsets of greater than one to one (i.e., 1.2 to 1) which is
consistent with the EPA's 1986 Emissions Trading Policy.
Commenter IV-D-27 recommended the following revision for
§63.745(d)(2)(iii) as follows:
"(2) (iii) Averaging both controlled and uncontrolled
primers together or both controlled and uncontrolled
topcoats together is allowed provided the daily volume-
weighted average of VOC and organic HAP comply with the
specified content levels."
Response: The EPA has collected data that indicate that the
emission limits for topcoats and primers are currently being met
by the industry. The emissions averaging plan contained in the
rule grants facilities flexibility in choosing compliance
options. Averaging between controlled and uncontrolled sources
was not included in the rule because there is no technical
justification for including such a provision. If a facility
chooses to implement control devices in order to achieve the
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emission limits specified in the rule, than all of the emissions
should be controlled. The EPA cannot allow a facility to
selectively choose which emissions to control. The new averaging
proposal discussed in the previous response will address this
issue.
6.12 EMISSIONS CONTROL
6.12.1 Control Efficiency
Comment: Commenter IV-D-43 noted that the proposed
regulation requires the control device to reduce the HAP and VOC
emissions by 81 percent or greater. The commenter pointed out
that AQMD's Rule 1124 has the following requirements for the
overall control efficiency requirements of VOCs:
1. The control device shall reduce emissions from the
emission collection system by at least 95 percent, by
weight; or,
2. The output from the control device should be less than
50 ppm, calculated as carbon with no dilution; and,
3, The collection system is at least 90 percent efficient
by weight.
The commenter recommended that the EPA adopt a similar
approach for VOC control, and is concerned if similar control
requirements are feasible for HAPs.
Response: The EPA adopted the 81 percent control level to
provide facilities with greater flexibility in the design of
their emissions control system. The EPA believes that by not
specifying capture and control efficiencies, facilities will have
more choices in their equipment design.
Comment: Two commenters (IV-D-27, IV-D-30) recommended that
the EPA delete the phrase "all of the" from §63.745(c)(1) as
follows:
"(1) The control device shall be designed to capture and
control all of the emissions from a coating application
operation."
Commenter IV-D-27 believes that the word "all" could be
interpreted to mean 100 percent and therefore should be deleted.
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The commenter stated that it is generally accepted that control
devices cannot achieve 100 percent efficiency.
Response: The EPA published revisions regarding the use of
the phrases "all of the" and "incidental" emissions in the
November 22, 1994 Federal Register notice. These phrases were
eliminated from the rule.
Comment: Commenter IV-D-27 recommended the following
revisions to §63.749(d)(3)(ii)(A):
"(A) All of fche emissions will be controlled by the control
device, except for emissions that may escape the capture
system when the capture system is operated per the
manufacturing or company specifications ai*e—coiiti'dlled by
criecoi~it iTO-Ldevice.
The commenter stated that this paragraph needs to be
clarified because "all" emissions could be interpreted to mean
100 percent of the emissions. The commenter believes this is
impracticable given technology has not achieved 100 percent
regarding control/capture efficiency. Also, the commenter
suggested that the term "incidental" needs to be defined or
removed from this paragraph. Additionally, the commenter stated
that if this paragraph, as proposed, is interpreted to suggest
all emissions will be controlled by the control device, then it
is in conflict with the stated efficiency of 81 percent. The
commenter claimed that it is generally accepted that control
devices cannot achieve 100 percent efficiency, that 100 percent
is theoretical and cannot be achieved.
Response: The EPA has deleted proposed §63.749(d)(3)(ii)(A)
from the final rule. The final rule deleted Method 309 for
determining the control efficiency of carbon adsorbers and now
contains specific provisions for carbon adsorbers.
Comment: Commenter IV-D-29 suggested that the EPA provide a
"hard control" option that would allow industry to "overcontrol"
emissions from coating operations. The option proposed by the
commenter would allow a facility to install equipment that would
"overcontrol" emissions beyond the 81 percent standard proposed
in §63.745(c)(2). The commenter stated that the delta
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"overcontrol" beyond 81 percent will be the amount of control
necessary to offset the lack of. high transfer efficiency (HTE)
application techniques. Therefore, the commenter concluded that
the approach would be to first determine emission reductions
achievable from HTE techniques, similar to the testing outlined
in §63.750 (i). Having determined those emission reductions
achievable from HTE, an equivalent "overcontrol" could be
calculated as follows:
ECE = P + (81 percent)(1 - P).
In summary, the commenter requested that facilities be
allowed to control emissions at an 81 percent reduction level
plus the calculated emissions reduction level that would be
achieved by using HTE application methods.
Two commenters (IV-D-29, IV-D-30) recommended the following
addition for §63.745(e)(4):
"Compliance with the emission reduction requirements in
paragraphs (e)(1)(i) through (e)(1)(vii) of this section,
which are accomplished as a result of reduced coating usage
through more efficient application methods, may also be
obtained through installing higher efficiency capture and
destruction equipment than would otherwise be required in
paragraph (c)(2). Compliance rests on demonstrating a total
emission reduction equivalent to that obtained from
installing hard controls (81 percent reduction) plus that
obtained from converting to application techniques
equivalent to HVLP or electrostatic application techniques."
Commenter IV-D-42 noted that the proposed rule
[§63.745(c)(1)] prohibits an add-on emission control system from
being designed to capture only a portion of the emissions from
nonexempt coating application operations. The commenter believes
that this provision may lead to unnecessary costs in capturing
and controlling small amounts of HAP or VOC in low concentration
emission streams. According to the commenter, the control system
need not capture all emissions as long as the overall emission
reduction is at least 81 percent (including all non-captured
emissions). The commenter, therefore, recommended that the
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overall emission reduction requirement remain at 81 percent, but
that an add-on emission control system be allowed to capture only
a portion of the total emissions.
Response: The EPA believes that a sufficient number of
compliance options have been offered which afford facilities a
great deal of flexibility. The EPA believes that the options
proposed by the commenters would significantly increase the
regulatory burdens on the Agency and the aerospace industry. The
EPA will, however, address pollution prevention alternatives in
an emissions averaging plan that will be issued as a supplemental
proposal to the final rule and will consider the commenters1
suggestions in the development of the proposal.
Comment: Two commenters (IV-D-42, IV-D-52) pointed out that
the proposed rule [§63.745(f)] does not specify any device
removal efficiency or overall control efficiency for inorganic
HAP add-on emission control systems. The commenter recommended
that on overall control efficiency or device removal efficiency
be specified.
Commenter IV-D-52 stated that it may be difficult or
impossible to determine control device efficiency by source
testing on dry particulate filters and waterwash systems, and
that appropriate ventilation requirements may also may be
difficult to generalize in a rule. The commenter, therefore,
recommended that the rule contain more detailed information
regarding what capture and control systems are required, or
specify that the detailed requirements be established on a case-
by-case basis at the discretion of the permitting authority.
Response: The final rule does not contain a control
efficiency requirement for particulate filters used to control
inorganic HAP emissions from coating operations. The EPA has
revised the standard and has adopted provisions that specify
workplace standards. In addition, the EPA is currently
investigating a number of options with respect to implementing
controls on the emissions resulting from coating operations.
Test methods are being developed which will allow filter
manufacturers to qualify their filters as EPA-approved. The
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Agency would then require affected sources to use EPA-approved
filters in the control devices used to capture the particulates
resulting from the coating operations. The EPA must determine
the best way to implement the provisions and will issue a
supplemental proposal to the NESHAP that will solicit public
comments on a provision that the Agency deems to be enforceable
and guarantees the public's safety.
6.12.2 HEPA Filter Use
Comment: Two commenters (IV-D-76, IV-D-90) supported a
provision that would require new source coating operations to
install HEPA filters.
Commenter IV-D-76 strongly supported the high efficiency
particulate filter requirement for new sources and recommended
that the EPA apply this requirement to existing sources as well.
The commenter stated that there is growing evidence that
particulate matter is responsible for thousands of deaths per
year. The commenter also recommended stricter controls of
particulates from new and existing sources for this and
subsequent MACT standards. The commenter suggested that
reduction requirements be specified at the 0.3 micron level in
order to reduce small particulates.
Commenter IV-D-90 supports the HEPA filter amendment because
the amendment is limited in scope such that it applies only to
new sources and because the amendment is limited to spray-applied
coating operations due to the generation of particulate matter.
Five commenters (IV-D-79, IV-D-80, IV-D-81, IV-D-83,
IV-D-85) were opposed to the proposed HEPA filter requirement.
Two commenters (IV-D-81, IV-D-85) stated that HEPA filters are
used in a "clean" room environment for the manufacture of
electronic components and circuits.
Three commenters (IV-D-80, IV-D-81, IV-D-83, IV-D-85)
believe that the cost of hangar-sized filtration systems would be
prohibitive. Commenter IV-D-81 stated that the cost of adding
HEPA filter systems has been reported as $3 to $4 per cubic feet
per minute (CFM) of air flow. Commenter IV-D-80 stated that the
cost can range from $2 per CFM to $8 per CFM. Commenter IV-D-81
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pointed out that typical aerospace paint booths are sized at over
200,000 CFM, resulting in costs from $600,000 to $800,000 just
for the filter system. The commenter believes that the cost is
excessive when considering the amount of particulate that will be
captured by the filter.
Two commenters (IV-D-80, IV-D-85) do not believe that HEPA
filtration technology has been demonstrated to be effective,
economically viable, or necessary for controlling inorganic HAP
emissions in aerospace coating operations. The commenters
claimed that the filters do not represent demonstrated technology
in areas large enough to service commercial aircraft, large paint
hangars, or even on open paint booths for large aircraft parts.
Commenter IV-D-80 recommended that paint hangars be exempt if the
EPA implements a HEPA filter requirement, since the Agency has no
information that the technology is used in practice. Commenter
IV-D-85 stated that the EPA has made no showing that the source
cited in the Federal Register notice is similar in scope, size,
or type of operation to a large airline rework painting facility,
as is required for new source standards by section 112(d)(3) of
the Clean Air Act.
Two commenters (IV-D-80, IV-D-85) also stated that the EPA
has not conducted an adequate analysis of the costs and non-air
quality health and environmental impacts and energy requirements
as mandated by section 112(d)(2) of the Act.
Commenter IV-D-79 was concerned that the EPA has
extrapolated the presence of HEPA filters at one facility's
coating operations into a MACT standard for all primer and
topcoat operations involving any inorganic HAP.
Commenter IV-D-80 noted that the 99.97 percent control
efficiency for HEPA filters is a manufacturer's representation
and does not represent actual source test results. The commenter
believes that the EPA should have actual test data before
mandating a control efficiency at a specific particulate size, or
alternately, allow the use of manufacturer's specifications for
compliance.
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Commenter IV-D-80 was concerned that if the HEPA filter
requirement is adopted, the proposed language at §63.745
(f)(2)(ii) could be read to require the stacking of more than one
bank of HEPA filters. The commenter requested that if the EPA
proceeds with the HEPA filter requirement, the EPA should clarify
that only one bank of filters would be required.
Two commenters (IV-D-79, IV-D-80) suggested that if the EPA
proceeds with the HEPA filter requirement, the EPA should specify
that the MACT standard applies only to hexavalent chromium
emissions from chromated primers. Commenter IV-D-79 stated that
the EPA should treat chromium-containing primer and topcoat
application as a distinct source category. Commenter
IV-D-80 recommended that a chrome concentration and quantity be
specified and commenter IV-D-79 recommended that the requirement
also apply to chromated topcoats. Both commenters stated that
facilities which do not have to consider hexavalent chromium
emissions will view the additional cost of maintenance and
installation of HEPA filters as unacceptable.
Commenter IV-D-80 stated that without a threshold
concentration limit, HEPA filters could be required on many
insignificant sources.
Commenter IV-D-85 stated that paint overspray particulates
are typically no less that 2.8 microns in size. Commenter
IV-D-80 pointed out that an analysis by the Air Force indicated
that the particulate size entering the filter is greater than 2
microns. Therefore, two commenters (IV-D-80, IV-D-85) believe
that the 0.3 micron filtering system as specified in the proposed
rule would not significantly increase filtration efficiency.
Commenter IV-D-83 conducted an evaluation of the
distribution of particulate mass from one 100,000 cubic feet per
minute (CFM) aircraft coating operation at Tyndall AFB. The
commenter also received data from Sinks Manufacturing Company on
particle size data for the Binks MACH 1 HVLP paint gun. The
commenter's conclusion from these limited data was that the
submicron particles in the exhaust from primer and topcoat
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applications represent less than 1/10,000 of the total
particulate mass.
Commenter IV-D-83 stated that multiple stage (double or
triple) dry filters can remove as much as 99.9 percent of the
total particulate mass. The commenter also noted that HEPA
filter systems can remove as much as 99.97 percent of total
particulate mass down to very small particle sizes. The
commenter also stated that a triple stage filter system is
capable of a 99.9 percent total particulate mass reduction.
The commenter stated that their analysis indicated that HEPA
filters remove only minor amounts of additional inorganic HAP at
a substantial cost (over $18 million per ton). According to the
commenter, based on the national average of PM10/ the HEPA system
would lead to a 57.1 Ib/year increase of PM10 at the power plant
to reduce the inorganic HAP from the coating process by only 7.4
Ibs/year. The commenter stated that the EPA needs to conduct a
more thorough analysis before switching to HEPA filters.
The commenter also stated that two single stage dry systems
at McClellan AFB were found to emit approximately 0.13 Ibs of
inorganic HAP per ton of coating sprayed. The commenter stated
that the filters themselves did not achieve this level of
efficiency in laboratory testing. The commenter believes that
the apparent 99.6 percent filter efficiency must be due to other
factors, such as a fall out rate much larger than 20 percent.
According to the commenter, for a 464,000 CFM system (operating 3
shifts, 251 days/year) the cost would reach $193,042/year to
control an additional 2.4 Ibs of inorganic HAP. The commenter
claimed that the result is $161 million/ton of emissions reduced,
with secondary PM:o emission of 44.35 Ibs at the power plant
(based on the emissions of 44.35 Ibs at the power plant (based on
the California average). The commenter believes that the EPA
should conduct further analysis before adopting any standard
beyond waterwash and dry filters. The commenter included their
data and analysis from the study.
Three commenters (IV-D-79, IV-D-80, TV-D-90) recommended
that the EPA revise the proposal by setting an alternative
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standard of performance which would allow less costly high
efficiency particulate removal systems to be installed. Two
commenters (IV-D-79, IV-D-80) pointed out that data from filter
manufacturers presented to the EPA indicated that very high
efficiencies are achievable with two- and three-stage filters.
Commenter IV-D-79 suggested that the EPA use the model plant
scenarios to determine what control efficiency is required to
adequately reduce emissions and mandate that control efficiency
as an alternative. According to commenter IV-D-79, HEPA filters
will satisfy that control requirement. The commenter believes
that a facility should have an option to use other types of
filtration that meet that control requirement. Two commenters
(IV-D-79, IV-D-80) stated that the manufacturers of HEPA filters
should have the opportunity to have their filters tested by some
testing organization so they can market them as NESHAP compliant
filters, thus removing some of the testing burden from the
facilities.
Two commenters (IV-D-79, IV-D-80) pointed out that the above
approach was incorporated by the EPA into the Halogenated Solvent
Cleaning NESHAP. According to the commenters, in that NESHAP,
controls could be chosen from a menu of options or alternative
controls that meet an emission standard.
Response: The EPA is required to impose emission limits for
new sources which represent the best technology in use at the
time of promulgation. The EPA determined that the use of HEPA
filters to reduce emissions sets is appropriate for the new
source MACT. Data were also received by the Agency which
indicated that two- and three-stage dry filters could achieve
equivalent results to HEPA filters. Therefore, the EPA has
imposed an equipment specification for new sources and has
specified that two-stage dry particulate filters shall be used to
control particulate emissions from coating operations. In
addition, if the coating contains chromium or cadmium, then new
sources must use three-stage particulate filters or HEPA filters
to control the particulate emissions.
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Comment: Commenter IV-D-83 stated that the proposal to
require HEPA filters (§63.745) for new primer and topcoat
applications raises the additional issue of whether projects
currently in development must comply with the new higher
standard. The commenter stated that a great amount of time and
expense has been incurred to design and build new facilities that
will comply with the pre-HEPA filter requirement. The commenter
stated that these projects should be exempted or the funds
expended thus far will be completely wasted.
Commenter IV-D-83 proposed that the EPA define a stage of
development for a project. The commenter stated that a
definition for development stage would be used to determine
"existing" versus "new" for compliance purposes. The commenter
stated that for military construction projects, the appropriate
stage should be the "PD" or Project Definition stage.
Response: Projects that are completed prior to the 3 year
compliance date will be considered "existing" and projects
completed after the compliance date will be deemed as "new"
sources. This action gives facilities a 3-year notification
prior to full implementation of the rule.
Comment: Three commenters (IV-D-79, IV-D-80, IV-D-83)
stated that the EPA has not indicated that any company has
installed HEPA filters as a retrofit technology to control
inorganic HAP emissions from waterwash booths. According to the
commenters, installation of HEPA filters for waterwash spray
booths is more difficult and more costly because the moisture
entrained from the water curtain will prevent the HEPA filters
from operating properly. Commenter IV-D-83 stated that such a
system would likely require the addition of a water separator to
remove high moisture in the exhaust air prior to entering the
HEPA filters. The commenter claimed that the cost and technical
feasibility of a high CFM water separator are unknown factors.
Thus, the commenter believes there is no foundation for
establishing a new source requirement adding HEPA filters to
waterwash systems. Two commenters (IV-D-79, IV-D-80) stated that
if the EPA would allow a reasonable alternative control standard,
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industry would have more flexibility and could achieve the
standard at a lower cost than for HEPA filter installation.
Commenter IV-D-83 collected data on a 464,000 CFM waterwash
operation in 1993. The commenter indicated that the waterwash
operation had an inorganic HAP emission rate of 0.21 Ib of
inorganic HAP per ton of coating sprayed, which results in a
99.92 percent control efficiency of the inorganic HAP used in the
process.
The commenter stated that the cost of retrofit easily
exceeds $4/CFM--about twice the cost of new construction. In
some cases, the commenter believes that modifications could
exceed the cost of constructing a new hangar. The commenter
requested that the EPA clarify the limits on "new source" in the
proposed rule.
Three commenters (IV-D-79, IV-D-80, IV-D-83) stated that the
HEPA filter issue is important because modifications to waterwash
booths can also be treated as major modifications subject to new
source MACT in the future. According to the commenters,
maintenance and replacement of parts due to corrosion can exceed
50 percent of the value of the booth. The commenter stated that
this type of maintenance is not related to an emission increase
or change in the coating operation. The commenters interpreted
the general provisions as stating that this type of maintenance
operation may deem the waterwash booth as "reconstructed" and
thus subject to the new source MACT.
Two commenters (IV-D-79, IV-D-80) recommended that the EPA
clarify that the Aerospace NESHAP supersedes the language of the
General Provisions. Three commenters (IV-D-79, IV-D-80, IV-D-83)
requested that the EPA specify that HEPA filters would not be
required for reconstruction of a waterwash booth and that
replacement of components of waterwash booths, modifications, and
retrofit do not subject a source to new source MACT requirements.
Response: For new sources, the EPA has adopted a
performance standard for emissions control systems. The standard
does not require the installation of HEPA filters on waterwash
booths. However, new sources must use three-stage particulate
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filters or HEPA filters to control emissions from coatings which
contain chromium or cadmium. The Agency has not specified the
order in which the three stages of filtering media must be
installed in order to provide affected facilities with compliance
options. In addition, §63.753(a)(1) states:
" ...initial notification requirements for new or
reconstructed affected sources in §63.9(b)(3) through (5)
shall not apply."
6.12.3 Hangar Use
Comment: Commenter IV-D-39 stated that proposed
§63.745 (f) (1) would require coating operations to be performed in
a "booth or hangar in which the air flow is directed across the
part or assembly being coated and exhausted through one or more
outlets." The commenter claimed that in many surface coating
operations, a downdraft booth provides better and safer
performance. To clarify that this industry may use such
technologies, the commenter recommended adding the term
"downwards onto or" before the term "across the part or assembly"
to clarify that the provision does not restrict the industry from
using other paint booth or hangar configurations.
Response: The EPA has accepted this revision and has
incorporated the change in the final rule. Final §63.745(g)(1)
states:
"Apply these coatings in a booth or hangar in which air flow
is directed downward onto or across the part or assembly
being coated and exhausted through one or more outlets."
Comment: Two commenters (IV-D-2, IV-D-23) stated that there
are situations during assembly where aerospace components cannot
be reasonably moved into a spray booth for coating. The
commenters stated that it is not practical to move a large
subassembly into a paint hanger for a small coating operation and
since the amount of coating applied is relatively small and
occurs in a large building, there is little chance of inorganic
HAP being released to the ambient air. The commenters
recommended that the rule provide flexibility to the permitting
agency to exempt in the title V permit those circumstances where
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it is not technically feasible to paint in a booth by including
an exemption to be included in §63.745(f) which allows "painting
in an area identified in a part 70 permit, where the permitting
authority has determined that it is not technically feasible to
paint in a booth."
Response: The EPA accepts the commenters' recommendation
because it gives facilities an opportunity to define operations
that would have minimal emissions. The EPA does not intend to
regulate minimal emissions. The EPA also does not intend to
force emissions control on operations that have minimal impact on
a facility-wide basis. Therefore, §63.745(g)(4)(ix) states:
"Painting parts in an area identified in a title V permit,
where the permitting authority has determined that it is not
technically feasible to paint the parts in a booth."
6.12.4 Monitoring of Emissions and Shutdown Requirement
Comment: Proposed §63.745(f)(4) requires facilities to shut
down operations in response to a pressure drop that is outside
the limit(s) specified by the manufacturer. Four commenters
(IV-D-29, IV-D-32, IV-D-25, IV-D-37) believe that an allowed
period of operation should be available in lieu of the immediate
shutdown requirement. Three of the commenters (IV-D-29,
IV-D-32, IV-D-37) recommended that the provisions be amended to
permit completion of the current operation when the pressure drop
parameter is exceeded. Commenter IV-D-35 suggested that the
language be softened to require shutdown only if repair
operations cannot be accomplished within 24 hours.
Commenter IV-D-30 recommended that "operational shift" be
defined and provision be made for action to remedy easily
correctable excursions without requiring total operation
shutdown.
Four commenters (IV-D-29, IV-D-32, IV-D-35, IV-D-37) stated
that, with respect to painting operations, immediate
discontinuation of work prior to completion of the task would
needlessly result in wasted paint and other materials, along with
lost labor costs associated with surface preparation. According
to the commenters, since partially-painted components would
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likely have to be repainted entirely, the premature cessation of
an operation may also result in greater total emissions than
would completion of the initial operation with less than optimal
filter efficiency.
Commenter IV-D-11 stated that the most preferable method of
determining violations is to require an operational parameter to
be monitored and recorded once per shift. The commenter
suggested that the rule require that the system be brought back
into compliance before any painting is performed on the next
shift and that subsequent shifts that do not meet the standard
would constitute a violation. The commenter stated that this
would allow current shift work in progress to be completed before
a mandatory shutdown.
Commenter IV-D-35 recommended that §63.745 (f) (4) be revised
to read as follows:
"If pressure drop, as recorded pursuant to §63.752(d), is
outside the limit(s) specified by manufacturer's
instructions or locally prepared operation procedures, shut
down the operation immediately after the aircraft under-
going painting operation is complete and take corrective
action. The operation shall not be resumed until the
pressure drop is returned to the limits specified by the
manufacturer."
Commenter IV-D-29 recommended the following revision to
63.749(e)(2) and the addition of (3) to be consistent with
previous comments:
"(2) For particulate filter, it is shut down immediately at
the completion of the application to the aerospace vehicle
or components being coated whenever the pressure drop is
outside the limit(s) established for it and is not restarted
until the pressure drop is returned to the limit(s) (as
required in §63.745 (f) (4)); o_r_
(3) For waterwash booth, it is shut down at the completion
of the application to the aerospace vehicle or components
being coated whenever (1) the water path fails the visual
continuitv/flow characteristics check, or (2) where visual
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inspections are not applicable, the daily flow meter
requirements show an interruption in flowf or the booth
manufacturer's maintenance procedures have not been
performed as scheduled, and is not restarted until the
nonconformance is corrected."
Commenter IV-D-35 recommended that §63.749(f) (4) be revised
as follows:
"If the pressure drop, as recorded pursuant to §63.752(d),
is outside the limit(s) specified by the manufacturer, the
operation is to be shut down at the completion of the
application of the primer or topcoat currently being applied
to the aerospace vehicle or components being coated. The
operation shall not be resumed until the pressure drop is
returned to the limit(s) specified by the manufacturer."
Commenter IV-D-29 recommended that §63.745(f) (4) be revised
as follows:
"(4) If the pressure drop, as recorded pursuant to
§63.752(d), is outside the limit(s) specified by the filter
manufacturer, shut down the operation immediately at the
completion of the application to the aerospace vehicle or
components being coated and take corrective action. If (1)
the water path fails the visual continuity/flow
characteristics check, or 2) where visual inspections are
not applicable, the daily flow meter requirements show an
interruption in flow, or the booth manufacturer's
maintenance procedures have not been performed as scheduled.
the operation must be shut down at the completion of the
application to the aerospace vehicle of components being
coated and take corrective action. The operation shall not
be resumed until the pressure dirop is returned to the
1 imiL (s)—specified by the—manufacturer non-conformance is
corrected."
Commenter IV-D-29 recommended the following revision for
§63.753:
"§63.753(c) Primer and Topcoat Application Operations ...
(1) ...
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(vi) All periods where a coating primer or—topcoat
application operation was not immediately shut down at the
completion of the application to the aerospace vehicle or
components being coated when the pressure drop across the
particulate filters or waterwash was outside the limit(s)
specified by the manufacturer or the operator or for
waterwash booths when (1) the water path fails the visual
continuity/flow characteristics check, or (2) whgre visual
inspections are not applicable, the daily flow meter
requirements show an interruption in flowr or the booth
manufacturer's maintenance procedures have not been
performed as scheduled."
Response: The EPA has gathered information indicating that
the pressure drop parameter does not change rapidly. Quite
frequently, filters have to be changed monthly or weekly. The
continuous monitoring requirement means that a monitoring device
should be installed to alert the operator if the pressure drop
exceeds or falls below the filter manufacturer's specified
pressure drop parameters or if a change in the flow rate to
waterwash booths occurs. The monitoring device data should be
recorded once per shift, not continuously. The final rule does
not allow a facility to continue painting when the dry
particulate filter is not operational or if it exceeds the
pressure drop specified by the manufacturer because facilities
have sufficient lead time to change filter media. The rule also
does not allow facilities to continue coating operations when a
waterwash booth is not operational, flow is interrupted, or if
the water curtain has gaps that would allow emissions to escape.
The EPA will allow locally prepared operational procedures to be
used for filter operation in addition to the manufacturer's
specifications. The EPA has revised §63.745(g)(3) as follows:
"(4) If the pressure drop, as recorded pursuant to
§63.752(d)(1), is outside the limit(s) specified by the
filter manufacturer or in locally prepared operating
procedures, shut down the operation immediately and take
corrective action. If the water path in the waterwash
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system fails the visual continuity/flow characteristics
check, or the water flow rate pursuant to §63.752(d)(2)
exceeds the limit(s) specified by the booth manufacturer or
in locally prepared operating procedures, or the booth
manufacturer's or locally prepared maintenance procedures
for the filter or waterwash system have not been performed
as scheduled, shut down the operation immediately and take
corrective action. The operation shall not be resumed until
the pressure drop or water flow rate is returned within the
specified limit(s)."
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7.0 DEPAINTING OPERATIONS
7.1 EXEMPTION REQUESTS
Comment: Two commenters (IV-D-29, IV-D-35) stated that the
EPA should provide an additional exclusion from coverage for
depainting conducted on aerospace vehicles or equipment that is
out of service and no longer operational and intended for public
display. The commenters recommended adding paragraph (1) to
§63.746(a) as follows:
"(1) Aerospace vehicles [equipment! which are Tisl no
longer operational and are Fisl intended for or on public
display and are not easily capable of being moved are exempt
from the requirements of this section."
The commenters emphasized that this case constitutes a low
volume and frequency of coating application.
Response: The EPA accepts the commenters' recommendation
and has added a provision to the standard that exempts aerospace
vehicles and components which are intended for public display.
Comment: Two commenters (IV-D-33, IV-D-43) stated that they
support the proposed regulation to prohibit any HAP emissions
from any organic depainting operation, except for certain
specific operations (i.e., depainting radomes, spot stripping,
removal of decals, etc.), noting that, within their jurisdiction,
they have permitted a number of facilities to switch over from
methylene chloride to media blasting, using materials such as
plastic or wheat starch. Nevertheless, the commenters
recommended that the State or local agencies be given the
discretion to exempt a source from this requirement if a source
can demonstrate that the use of inorganic depainting is not
feasible. One of the commenters suggested that the criteria for
the case-by-case exemption be based on the following:
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1. The facility is concerned about safety issues and has
data to indicate that depainting with abrasive media or
other inorganic methods might lead to damage and build-
up of stresses in the aircraft frame;
2. The facility installs Best Available Control
Technology; and,
3. The emissions from the depainting operation meet the
local district's risk assessment criteria and New
Source Review regulations.
This commenter concluded by recommending that: (1) the rule allow
alternative methods for the depainting of aircraft, if they meet
local air pollution regulations, and (2) case-by-case exemptions
be allowed in the regulation without requiring a section 112(1)
equivalency submittal. The other commenter recommended that
§63.746(b)(3) be revised to include:
11 (iv) depainting of parts, subassemblies, and assemblies
approved, on a case-by-case, by the permitting agency."
Response: The EPA is mandated to promulgate national
standards for the control of HAP's utilizing maximum achievable
control and cannot allow local agencies to exempt facilities from
the minimum requirements. However, any State or local agency can
request that their program be evaluated for equivalency to the
NESHAP by submitting a request under section 112 (1) .
Comment: Commenter IV-D-36 requested that all depainting
performed on the U.S. Presidential ("VH") helicopter fleet be
exempted from the requirement to utilize non-HAP depainting
methods. The commenter is the sole contractor for the
manufacture, overhaul, and repair of the Presidential
helicopters.
The commenter stated that they investigated the use of non-
HAP paint stripping technologies and found that none of the
processes was technically adequate or cost-effective. The
commenter determined that use of the current methylene chloride-
based stripper on assembled Presidential aircraft would be
limited to only 800 gallons per year for the foreseeable future,
or at least through the remainder of the 1990's. Therefore, the
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commenter concluded that an exemption for this aircraft would not
result in a significant increase in the use of HAP-type
strippers.
Response: Under section 112, Presidential exemptions are
only given in cases where national security is threatened.
Additionally, the final rule allows a facility to use organic
HAP-containing chemical strippers when a control device is
installed on the operation to control the emissions. The number
of options available to the industry should not necessitate that
any facility seek an exemption from the standards.
Comment: Commenter IV-D-79 is pleased that the EPA is
considering control devices for depainting operations using HAP-
containing chemicals as an addition to the depainting standard.
The commenter stated that they know of no system which can
achieve an overall control efficiency of 99 percent and
recommended that an 81 percent control efficiency be adopted.
The commenter pointed out that their Tucson operations have a
UVOX control system installed to control organic HAP emissions
from HAP-containing strippers. The commenter doesn't believe
that it would be cost effective for any other companies to
install such a control device. The commenter stated that since
they have already installed the UVOX, they believe that the EPA
should allow it to operate under the NESHAP.
Response: The EPA has adopted a provision in the standard
which allows the use of HAP-containing chemical strippers as the
primary depainting technique when used with emission control
systems. New requirements have also been added to the rule which
specify the emissions control efficiency, recordkeeping,
reporting, and compliance procedures for the use of HAP-
containing chemical strippers. Control systems installed before
the effective date must reduce the operation's organic HAP and
VOC emissions to the atmosphere by 81 percent or greater.
Control systems installed after the effective date must reduce
the emissions by 95 percent or greater.
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Additionally, procedures are specified in the final rule
which provide a company with the means to obtain a compliance
determination for alternative control devices and systems.
Comment: Commenter IV-D-30 stated that without further
clarification, it is difficult to determine the applicability of
this rule to elements of the Space Shuttle Program and space
operations generally. The commenter pointed out that chemical
HAP-containing strippers are allowed for "commercial and military
aircraft;" other vehicles and equipment are not mentioned. The
commenter also recommended that the status of spacecraft be
further defined.
Response: Space vehicles designed for missions which exceed
the earth's atmosphere have been exempted from the rule. This
exemption has been addressed in §63.741, Applicability and
Designation of Affected Sources and includes the Space Shuttle.
7.2 APPLICABILITY
Comment: Commenter IV-D-27 stated that they support the
EPA's intent to control significant emissions from aircraft and
large aircraft wings and stabilizers. However, the commenter was
concerned with the limitations that proposed §63.746 would put on
small parts operations. The commenter recommended deleting the
reference to missiles and rockets on the basis that depainting
operations associated with missiles and rockets are small in
nature and are usually performed in a controlled environment.
Also, the commenter believes that depainting processes of this
scale will have a minimal environmental impact due to the small
size of these parts. The commenter stated that if this deletion
cannot be allowed, then they recommend the revisions listed
below, which would allow a de minimis value for exempting wings
and stabilizers on the same basis as mentioned above.
Commenter IV-D-35 suggested eliminating the word "entire" in
depainting operation applicability to prevent conflicting
interpretations of the term. The commenter stated that the word
"entire" can be interpreted too loosely or too restrictively, and
adds an unnecessary level of ambiguity. For example, the word
could be interpreted as meaning that mechanical sanding (or any
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depainting operation) is regulated as depainting only when it is
accomplished on the entire outer surface of an aerospace vehicle.
Thus, the cornmenter believes, an operation which scuff sands (or
chemically strips) 10-70 percent of an aircraft prior to painting
would not be regulated under §63.746(d). However, if "entire,"
as used in §63.746(a), means that depainting is regulated when
accomplished on an assembled (entire) vehicle, as opposed to
parts, then any amount of mechanical sanding on the outer surface
may be regulated under §63.746(d). The commenter concluded that
the first interpretation is too loose from an environmental
perspective, whereas the second interpretation is too restrictive
and would require the modification of all aerospace repair
hangars where any mechanical sanding is performed on the outer
surface of an aerospace vehicle.
Commenter IV-D-17 stated that they normally partially
disassemble their aircraft before depainting operations are
performed. From a reading of the proposed rule, the commenter
gained the impression that they would be exempted. The commenter
asked for clarification on this point.
Commenter IV-D-27 recommended the following revisions:
"§63.746 Standards: Depainting Operations
(a) Applicability. The provisions of this section apply to
the depainting of the outer surface areas of entire
assembled aerospace vehicles, including the fuselage, wings,
and vertical and horizontal stabilizers of the aircraft, ami
tilsoxitsir cfl.sxncf &nci st~&.D.i.-LxZj£i.s ot nilssiJ.&s 3111 el XTOCK.^us
The provisions do not apply to the depainting of parts or
units normally removed from the entire aerospace vehicle for
depainting. However, depainting of- aircraft wings and
stabilizers is always subject to the requirements of this
section regardless of whether their removal is considered by
the owner or operator to be normal practice for depainting.
(1) Aerospace facilities who use less thaq 50 gallons/year
on all combined aircraft parts are exempt from the
requirements of this section.
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(b)(1) Organic HAP emissions. Except as provided in
paragraph (b)(3) of this section, each owner or operator of
a new or existing aerospace depainting operation subject to
this subpart shall emit no organic HAP from the depainting
operation.
(3) The following depainting operations are exempt from the
requirements of paragraph (b)(1) of this section:
(iv) Wings and stabilizers with a surface area less than or
equal to six square feet are exempt from the requirements of
this section."
Another commenter (IV-D-29) recommended the following
revision to §63.746(a):
"(a) Applicability. Except as described below in paragraph
(l). the provisions of this section apply to the depainting
of the outer surface areas of entire aerospace vehicles,
including the fuselage, wings, and vertical and horizontal
stabilizers of the aircraft, and the outer casings and
stabilizers of missiles and rockets. The provisions do not
apply to the depainting of parts or units normally removed
from the entire aerospace vehicle for 'depainting. However,
the removal and depainting of aircraft wings and stabilizers
is always subject to the requirements of this section
regardless of whether their removal is considered by the
owner or operator to be normal practice for depainting."
Commenter IV-D-27 recommended adding a new paragraph (v) to
§63.746(b)(3) to exempt from the depainting requirements,
aerospace parts or components that have not reached final
assembly. The commenter stated that the rule essentially doubles
the recordkeeping requirements at no appreciable environmental
benefit. The suggested addition is as follows:
"(v) Aerospace parts or components that have not reached
final assembly."
Response: The EPA has revised the standard and has adopted
a provision which requires that all depainting operations be
conducted in a controlled environment.
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The EPA intended for the word "entire" to indicate that the
standard covers the depainting of the outer surfaces of aircraft.
The surfaces include the fuselage, wings, tail, and horizontal
and vertical stabilizers. Also, removable panels or sections of
coated surfaces located on the outer surface of the aircraft that
may be considered a part of the "fuselage," such as on
helicopters, are intended to be covered by the standard. The EPA
has deleted the word "entire" from the provision in order to
remove ambiguity from the rule. The EPA believes that the
provision clearly reflects the Agency's intent without the use of
this word.
With respect to the commenter's request that "assembled" be
substituted for "entire," there may also be instances where one
small part may not be attached to the vehicle and, therefore, the
vehicle would not be considered "assembled." In this case, a
facility could interpret the standard to mean that the provision
does not apply to the vehicle. Additional ambiguity may be added
if "assembled" were adopted. Therefore, the EPA will not adopt
the word "assembled" as a substitute for "entire."
Additionally, the EPA has not adopted a provision which
exempts from the standard any facility that uses a total of 50
gallons or less per year of chemical stripper for parts because
parts are not covered by the standard. The EPA did not adopt
provisions in the proposed or final rule for parts depainting
because the information collected by the Agency indicated that a
large majority of the industry currently uses media blasting on
parts and assemblies. Additionally, the EPA did not specify
requirements for parts depainting because the emissions from this
source are minimal when compared to the depainting of the
fuselage, wings, and stabilizers.
7.3 DRY MEDIA BLASTING
Comment: Commenter IV-D-47 was concerned about the EPA's
evaluation of non-chemical-based depainting techniques, which
focus on media blasting. First, the commenter stated that the
EPA relied almost exclusively on data from military operations in
evaluating the health and environmental impacts of media blasting
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techniques. The commenter believes that reliance on military
data is not an adequate or even a relevant data base for
evaluating the environmental and health impacts of media blasting
for commercial aerospace facilities, given the obvious
differences in commercial and military depainting operations such
as size, equipment, types of planes, parts, and substrates
stripped, as well as safety and other regulatory requirements.
Also, the commenter claimed that an evaluation based on such data
is not sufficient for a proper MACT determination.
Response: Information was collected from a variety of
sources in the industry, including the military. The docket
contains information from several commercial facilities that use
media blasting and non-HAP strippers. Recent advances in the
media blasting industry have increased the efficiency of the
operation. The standard does not specify that a particular
technique or method be used for depainting operations. The EPA
encourages the industry to evaluate all depainting methods and
techniques.
Comment: Commenter IV-D-38 stated that while several
techniques exist, only two blasting technologies, plastic media
and wheat starch, have been employed in other than
experimental/pilot applications. The commenter claimed that the
rest of the techniques described in the EPA's background
information document remain in their developmental stages. As a
result, the commenter stated that the EPA's review of blasting
technologies as part of its development of MACT for depainting
operations should be limited to dry media blasting with plastic
media and wheat starch.
Response: The docket contains information that several
types of media have been used successfully to strip aircraft.
Additionally, the EPA would like to share information on emerging
technologies, such as C02 blasting, sodium bicarbonate blasting,
high pressure water blasting, grit blasting, glass bead blasting,
aluminum oxide blasting, wheat starch blasting and the various
plastic media that have been used for blasting depainting
operations. The EPA has not restricted depainting operations to
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any particular technique or method. The standard states the
level of control that must be achieved in order to reduce
emissions from depainting operations.
Comment: Commenter IV-D-87 stated that the ENVIROSTRIP
wheat starch based dry stripping process has been successfully
used in various aircraft coating removal applications since 1991.
The commenter claimed that two of the largest corporate/private
aircraft manufacturers, Beech Aircraft and Cessna, currently use
the process in-house to remove coatings and flashing from
aircraft subassemblies, including applications on very thin
aluminum.
According to the commenter, Hunting Aircraft (now Stevens
Aviation - Peachtree City, Georgia) has successfully utilized a
manual wheat starch dry stripping system on numerous corporate
and private aircraft for nearly 2 years. The commenter also
claimed that Boeing has authorized unlimited use of the wheat
starch dry stripping process on aluminum surfaces as thin as
0.032 inch and that Northrop exclusively utilizes the process on
the very sensitive, high-tech composite B-2 stealth aircraft.
The commenter stated that the USAF has wheat starch based dry
stripping programs in place for both composite and full aircraft
stripping. Additionally, the commenter stated that the European
Airbus has also authorized the use of this process.
The commenter stated that difficulties have been encountered
from a technology development standpoint to make the process as
economically competitive (time and materials) as HAP-based
chemical strippers.
The commenter stated that the ENVIROSTRIP process has
obtained more optimization since the first corporate aircraft was
stripped at Hunting Aircraft in 1992. The commenter pointed out
that with the state of technology at the time, Hunting could not
stay competitive with others using HAP chemical strippers and was
forced strictly by economics to change back to HAP chemicals.
The commenter claimed that Hunting was able to successfully dry
strip all corporate and private aircraft presented, but material
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(media consumption) and labor costs were higher than HAP chemical
processes used by competitors at that time.
The commenter claimed that they have been successful in
removing all commercially known aircraft coatings, including
those used on corporate and private aircraft. According to the
commenter, some coatings are removed faster than others, but
removal is achieved without damage to the surface. The commenter
noted that they have also made their test facility available to
all OEM's conducting process approval testing.
The commenter believes that Northrop1s successful stripping
of the high-tech, sensitive surface (both structurally and radar
detection) B-2 stealth aircraft, using the ENVIROSTRIP process,
demonstrates how adaptive this technology is. The commenter
stated that with the current investments by Archer Daniels
Midland, CAE Electronics, and other supporting dry stripping
industry organizations, the overall process is now more
competitive than before and a viable alternative to the continued
use of HAP-based chemicals.
Response: The EPA supports the use of media blasting along
with any other technique or method that does not emit HAPs.
Comment: Commenter IV-D-38 stated that while several
military facilities depaint fighter planes and other military
aircraft with thicker skins, a number of facilities have
submitted comments to the EPA concerning the inability to use
media blasting techniques on thin-skinned military aircraft,
including transport planes and bombers. The commenter pointed
out that the U.S. Air Force, for example, does not permit
abrasive paint removal on thin-skinned aircraft (e.g., C-135's
and B-52's) because of its concerns over cladding removal, metal
fatigue, and stress cracking. The commenter maintained that even
wheat starch blasting, which appears to be less abrasive than
plastic media, lacks the necessary materials-qualification data
and no foreseeable milestones for military implementation of the
wheat starch technology on large, thin-skinned aircraft.
The commenter suggested that while partial dry-media
stripping may be possible for (thin-skinned) military bomber and
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transport aircraft, it is unlikely that a media process will be
approved for stripping of the entire aircraft.
Commenter IV-D-47 stated that where safety is a paramount
concern, media blasting should not be recommended for use in
depainting operations without further research, particularly for
use on commercial aircraft. The commenter pointed out that
several airlines do not recommend plastic media blasting for use
on composite substrates, or for repeated depainting cycles on
certain metal types or thickness, because it may cause severe
damage and metal fatigue, implicating serious public safety
concerns.
Commenter IV-D-45 stated that wheat starch shows some
promise as a mechanical stripper, but it has some drawbacks since
it can easily be contaminated with metal fines, sand, airborne
abrasive media, dust, etc. The commenter pointed out that this
contamination causes increased metal removal and can cause
pitting or surface failures to occur prematurely from local area
fatigue resulting from impact damage.
Response: The docket contains information on many
depainting techniques and methods that have been successfully
employed on a wide variety of aircraft. In a current test
program with NASA and the Air Force, the EPA is investigating
several stripping methods that do not utilize methylene chloride.
It is not the EPA's intention to endorse or reject any particular
depainting method. The EPA has specified in the standard the
level of control that shall be achieved for organic and inorganic
HAP emissions from depainting operations. A wide range of
depainting options are available to facilities. It is possible
that some facilities will choose a combination of techniques.
Comment: Commenter IV-D-5 stated that the effect on the
structural integrity of the substrate of an aircraft has always
been one of the most important factors in determining the
usability of a chemical paint remover, yet the proposal ignores
this problem with media blasting, a method the depainting
industry has always refused to use due to potential damage to the
aircraft.
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Response: Section 114 questionnaire responses and site
visit information have indicated that many facilities currently
use dry media blasting to depaint aircraft without any reports of
adverse effects.
Comment: Commenter IV-D-5 stated that it is amazing that
the EPA would even suggest the use of media blasting as a
possible solution to air emissions, let alone think that this
method could maintain a 99 percent level of control. The
commenter suggested that a visit to any media blasting facility
will show the inability to control inorganic HAP emissions. The
commenter claimed that the property around these facilities will
be surrounded by particulates from the paint, heavy metals from
the substrate, and residue from the media.
This commenter stated that the media blasting industry is
the dirtiest and greatest source of environmental pollution
within the coating removal industry. The commenter also claimed
that to leave the "operation" of the equipment up to the facility
would only encourage the aircraft industry to continue the
current work practices of the media blasting industry.
Response: The commenter did not provide any specific
support for their comment.
Comment: Commenter IV-D-38 noted that dry media blasting
requires dust collection and media separation and recycling
systems. The commenter stated that media blasting produces a
considerable amount of dust (from the paint and breakdown of the
media) that must be collected. Otherwise, the commenter claimed,
the dust generated during the blasting operation can create an
unsafe working environment and interfere with other maintenance
operations occurring at the same time. The commenter believes
that the generation of dust requires worker protection and air-
supplied respirators and, in the case of wheat starch blasting,
may create potential for explosion. According to the commenter,
while much (90 percent or more) of the dry media can be recycled,
the reusable material must be separated from the waste paint and
dust.
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Response: The information collected by the EPA indicates
that respirators are commonly used during all depainting
techniques and methods currently used by the industry.
7.4 CHEMICAL STRIPPING METHODS
7.4.1 HAP-containing Strippers
Comment: Commenter IV-D-47 stated that many of the
alternative chemicals that will take the place of methylene
chloride (DCM) chemical strippers are not classified as HAP only
because they have not been tested or used extensively, so
adequate human health and environmental data are not available to
characterize the risks of their use. According to the commenter,
because none of the non-HAP alternatives have been tested as
extensively as methylene chloride, the EPA's recommendation that
such untested chemicals be adopted as MACT to the exclusion of
methylene chloride is somewhat surprising. The commenter pointed
out that it is even more surprising since the EPA previously
designated methylene chloride as an acceptable alternative to
ozone-depleting chemicals in various use sectors in implementing
its Significant New Alternative Policy program.
The commenter suggested that the proposed standard appears
to be inconsistent with ongoing rulemaking and pollution
prevention initiatives relating to paint stripping. The
commenter stated that the Occupational Safety and Health
Administration (OSHA) is in the process of adopting a standard
that will fully protect the health of workers in, among others,
aircraft depainting operations. (56 FR 57036, November 7, 1991.)
The commenter asked the EPA to explain how a ban on chemical
strippers is legally or scientifically justified if the workers
are fully protected by a workplace standard.
Additionally, the commenter noted that the EPA recently
announced the formation of a Paint Stripping Use Cluster. The
commenter pointed out that the principal purpose of the activity
is to compare the potential risks of methylene chloride and
alternative paint strippers, at least one of which has been found
by the EPA to present a "'significant risk' of reproductive and
developmental effects." The commenter claimed that by law and
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its own policy, the EPA must carefully consider the health and
environmental effects of alternatives before effectively seeking
to ban a listed HAP, and the EPA seems only to have begun the
process of reviewing such alternatives.
The commenter strongly believes that the available
scientific evidence does not support the extreme nature of the
proposed depainting provisions, which amount to a virtual ban on
methylene chloride use. According to the commenter, methylene
chloride is listed as an HAP solely by virtue of its carcinogenic
potential. The commenter pointed out that the full body of the
epidemiological and toxicological data on methylene chloride
makes a compelling case that methylene chloride is unlikely to
pose a cancer risk to humans at current exposure limits in
industry, including stripping of aircraft, a use sector that was
discussed at length at the OSHA hearings and rulemaking.
Commenter IV-D-5 claimed that methylene chloride is listed
as a HAP only because it is considered a suspect carcinogen.
However, the aircraft refurbishing industry has consistently
opposed the classification of methylene chloride as a carcinogen
due to a perfect health record with the use of this chemical.
The commenter felt that studies funded by the refurbishing
industry to be published in late 1994 would demonstrate that
methylene chloride should not be listed as a suspect carcinogen
and a HAP. The commenter believed that this study would alter
the proposed NESHAP standard by allowing the continued use of
methylene chloride paint removers.
Response: There is an existing procedure, as required under
section 112, for petitioning that a chemical be removed from the
section 112 list. The EPA has not banned or regulated the use of
any individual chemical under this NESHAP. The EPA is mandated
to regulate the emissions resulting from the use of HAPs.
Additionally, the EPA has revised the standard to allow the use
of HAP-containing chemical strippers in conjunction with control
equipment.
Comment; Commenter IV-D-38 remarked that the proposal to
prohibit HAP strippers effectively eliminates any possibility for
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implementing control techniques that could allow continued use of
these formulations, even though such techniques exist. The
commenter believes that this would be contrary to the intent of
the 1990 revisions to section 112 of the Act.
The commenter recommended that the EPA revise its proposal
to ensure both commercial and military compliance while still
achieving significant reductions in HAP emissions from depainting
operations. The commenter believes that both objectives can be
achieved by establishing separate commercial, military thin-
skinned (bomber and transport), and military thick-skinned
(fighter, etc.) emission rates for HAP strippers based on the
best performing five or more (i.e., 12 percent) sources in each
category. The commenter suggested that for simplicity, these
rates should be expressed on an emission per square foot of
aircraft surface basis and be based on an annual average.
The commenter believes that the depainting standards should
be designed such that facilities would have an incentive to
implement cost-effective, non-HAP stripping techniques, but could
continue to use HAP strippers for some period of time if they
chose to implement the necessary control measures/work practices.
Response: As stated in the previous response, the EPA has
revised the standard to allow the use of HAP-containing strippers
in conjunction with added control devices and work practices.
7.4.2 Non-HAP Strippers
Comment: Commenter IV-D-78 claimed that non-HAP strippers
have been proven to be effective, reliable, and economical for
the removal of cross-linked polymer coatings. The commenter
stated that several medium to large facilities use these products
routinely to strip private and corporate aircraft and that all
major domestic airlines are currently using these products,
either as their standard method of depainting, or as part of an
ongoing evaluation program. The commenter claimed that none of
the facilities have found non-HAP strippers to be ineffective on
cross-linked coatings, although some have expressed a wish that
they be made faster-acting.
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Commenter IV-D-5 believes that non-HAP strippers are not
effective in removing modern, highly durable coatings. The
commenter suggested that if the demand for non-HAP strippers
increases, the result will be the use of less durable coatings
that can be removed by less active removers and provide less
protection to the aircraft, thus decreasing its structural
integrity and creating a risk to the public. Commenter IV-D-47
stated that non-HAP strippers may be effective on some coatings,
but simply cannot remove certain coatings and paints. Commenter
IV-D-45 pointed out that the effectiveness of non-HAP strippers
is very sensitive to the paint system used, as well as the number
of layers of coating to be stripped.
Two commenters (IV-D-45, IV-D-47) claimed that most non-HAP
strippers also require a longer time for application, and have a
slower stripping rate. Commenter IV-D-47 also claimed that some
acidic strippers have a high potential for increasing corrosion
and fatigue of steel components. The commenter believes that
further testing is necessary before most non-HAP strippers can be
considered a proven technology that is effective for depainting
operations.
Commenter IV-D-38 pointed out that available information
indicates that there currently exist three basic formulations of
non-HAP stripper products: formic acid-based, ammonia-based, and
benzyl alcohol-based. The commenter claimed that, in addition to
concerns raised over the performance of these types of products,
information submitted to the EPA suggested that problems exist
with each of these formulations.
The commenter suggested that formic acid-based formulations
present significant concerns of hydrogen embrittlement of high-
strength steel parts (e.g., fasteners, hinge pins, and landing
gear), which can reduce aircraft fatigue life on these
components. The commenter claimed that because of the potential
for embrittlement of steel components, acid-based formulations
cannot be used on military aircraft. Further, the commenter
stated that data submitted by one major commercial airline
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suggested that these products are only effective on single-coat
paint systems, and are quite temperature-sensitive.
The commenter stated that ammonia-based formulations do not
appear to be effective on urethane paint systems commonly for
both commercial and military applications.
The commenter stated that non-HAP stripper formulations
based on benzyl alcohol appear to be limited to aircraft primed
with a polysulfide product. The commenter also suggested that
benzyl alcohol formulations do not appear to be effective on
epoxy primers. For these paint systems, the formulation has been
used as a softener and is followed by a high-pressure water spray
to remove the coating. The commenter suggested that in these
instances, adequate prevention of water entrapment and the
effects on composite structures need to be addressed.
Response: Some facilities reported information which stated
that they had no problems stripping with non-HAP strippers.
Other facilities reported that the non-HAP strippers would only
remove certain types of coatings and frequently needed additional
touch-up work, whereas still others stated that non-HAP strippers
can be used to strip topcoats and not damage the primed surface.
The regulation does not require that non-HAP strippers or
any other particular technique be used. The regulation offers
facilities many alternatives for depainting of aerospace
vehicles. There are many techniques and methods available that
meet the provisions in the final rule. The final rule provides
the industry with a great deal of flexibility in their choice of
compliance options.
Comment: Two commenters (IV-D-38, IV-D-47) stated that the
EPA used information from only one commercial facility as a basis
from listing non-HAP strippers as MACT. Commenter IV-D-38
suggested that the Agency's decision appears to be based on the
use of a formic-acid based product in an "on-going research
project" at one commercial aircraft maintenance facility.
Commenter IV-D-47 stated that a single source of information
is clearly insufficient to serve as the basis for a proper
evaluation of the health and environmental impacts of the use of
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non-HAP strippers, and is certainly not a proper basis for a
determination that non-HAP stripping should be the MACT standard.
Response: The fact that one large commercial facility
routinely uses a technology that contains no HAPs is significant.
Additionally, the docket contains information on a number of
facilities that have used non-HAP strippers. The EPA has
selected non-HAP depainting methods as MACT because this
technology provides the environment the maximum benefit.
Additionally, HAP-containing chemical strippers may be used with
abatement. Non-HAP chemical stripping does not require emissions
control and is just one of many techniques and methods which may
used under the standard.
Comment: Commenter IV-D-5 contended that the EPA's
statement that "nearly all models of commercial airliners are
currently being stripped with one or more of these non-HAP
methods" is false and not representative of the industry. The
commenter claimed that if this was a factual study, methylene
chloride depainting as performed by the industry would have been
used as the "floor," and the data collected are not sufficient to
set standards.
Response: The commenter is correct in stating that many
facilities use methylene chloride strippers to depaint aircraft.
However, the docket contains information to support the EPA's
position that non-HAP depainting methods have been used at many
facilities to strip commercial aircraft and constitutes the MACT
floor level of HAP control.
7.5 OTHER STRIPPING TECHNOLOGIES
Comment: Commenter IV-D-35 stated that the development of
non-HAP depainting processes within the aerospace industry has
evolved within the framework of three major technologies which
include abrasive blasting, high pressure water stripping, and
high energy light stripping. The commenter pointed out that
these technologies require significant capital expenditures for
both equipment and facility interfaces. The commenter also
pointed out that all of these techniques are heavily process
equipment dependent, and in most cases, the use of robotics and
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other high-tech equipment/components are employed. According to
the commenter, while these technologies insure successful non-HAP
aircraft paint removal, they are more susceptible to equipment
breakage and require a high frequency of scheduled maintenance
downtime.
Commenter IV-D-35 noted that one of the most technically
complex non-HAP processes currently being developed for military
use is the Large Aircraft Robotic Paint Stripping (LARPS) system.
The commenter stated that this system will be operational at
Oklahoma City Air Logistics Center in April 1995, and employs a
robot which uses high pressure water blasting to depaint large
military aircraft. The commenter pointed out that LARPS will
have a minimum system availability of 85 percent and will require
a 2-week annual downtime for scheduled equipment maintenance.
Response: The EPA encourages the industry to continue with
development of alternative non-HAP technologies.
Comment: Two commenters (IV-D-29, IV-D-35) believe that the
depainting definitions (§63.742) and depainting operations
standards (§63.746) in the proposed rule do not clearly address
mechanical sanding operations.
Commenter IV-D-35 pointed out that in some cases mechanical
sanding is used for bulk removal of paint. The commenter stated
that this is especially true for sensitive substrates which can
not tolerate currently developed chemical and non-chemical
stripping methods. The commenter also noted that the proposed
MACT for this type activity is a hangar with inorganic emission
controls. The commenter claimed that this is an inappropriate
MACT. According to the commenter, the emissions from bulk
removal of paint using mechanical sanding can be more effectively
controlled by using filtered vacuum sanders such as NILFISK Model
GB 933/GB 1033 with HEPA Exhaust Filter #215337. Since
mechanical sanding emissions can be equally contained (if not
better contained) from vacuum assisted sanders at a significantly
lower cost, the commenter, therefore, recommended that EPA
evaluate this technology for a mechanical sanding MACT, when
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mechanical sanding is used for bulk removal of paint. The
commenter stated that, for all other mechanical sanding
operations, the emissions are negligible and should not be
controlled.
According to commenter IV-D-35, it is difficult to determine
if mechanical sanding is a regulated operation under the proposed
rule. The commenter claimed that the MACT floor established for
controlling depainting related inorganic HAP emissions is
inappropriate for mechanical sanding.
The commenter noted that, when the primers and topcoats
contain inorganic HAP, the mechanical sanding operation leads to
small emissions of inorganic HAP. The commenter was concerned
that the proposed aerospace NESHAP standard as written would
inappropriately require the modification of thousands of
buildings into depaint hangars, as specified in proposed
§63.746(d), in order to accomplish mechanical sanding.
The commenter maintained that the descriptions of depainting
operations used in the model plants and in the subsequent section
114 data requests do not provide sufficient information to
establish a MACT floor for mechanical sanding. Therefore, the
commenter claimed that an appropriate MACT standard still needs
to be established for mechanical sanding, if it is included as a
regulated depaint activity.
The commenter also claimed that the requirements for
controlling inorganic HAP emissions from depainting operations,
specified in proposed §63.746(d), do not constitute a reasonable
control technology for mechanical sanding. In particular, the
commenter recommended that non-powered sanding, by hand or with a
pole attachment for extending reach, should not be regulated.
The commenter, therefore, recommended the inclusion of the
following definition for "mechanical sanding" in §63.742:
"Mechanical sanding means aircraft surface conditioning to
include the use of directional and random orbital tools and
aluminum oxide or nylon abrasive pads for the purpose of
corrosion rework, substrate repair, prepaint surface
preparation, or other maintenance activities."
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Commenter IV-D-35 also recommended the following change to
§63.746(d) to include the proposed exemption:
"Inorganic HAP emissions. Except as provided in paragraph
(d)(5) of this section, each owner or operator of a new or
existing depainting operation subject to this subpart that
generates airborne particulate emissions that contain
inorganic HAP shall comply with the requirements specified
in paragraphs (d)(1) through (d)(4) of this section."
Add paragraph (d)(5) to read as follows:
§63.746(d)(5) Depainting methods in which particulate
control is built into the stripping apparatus at the
emission source is exempt from paragraphs (d)(1) through
(d)(4) of this section. Depainting methods other than dry
media blasting are exempt from paragraphs (d)(2) through
(d)(4) of this section.
Commenter IV-D-29 recommended adding a paragraph to
§63.746 (e) as follows:
"(5) Mechanical sanding is excluded from these requirements
of this section when used in preparation for paint touchup
and repair or where an aerospace vehicle or component due to
its size or other operational considerations, cannot be
transported to and/or handled in a booth hanger."
Response: Mechanical sanding has always been an appropriate
mechanism for depainting. The EPA believes that the airborne
particulate emissions from mechanical sanding are minimal. The
final rule states that particulate air emissions from mechanical
sanding do not have to be controlled by particulate filter
systems.
7.6 MACT Floor
7.6.1 General Comments
Comment: Commenter IV-D-5 stated that if the overall
objective of the rule is the achievement of the maximum degree of
emission reduction without unreasonable economic or other
impacts, then the proposal should not limit methods of compliance
to a particular method of depainting.
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Response: Facilities are free to use many methods and
techniques to comply with the depainting standard.
Comment: Commenter IV-D-38 noted that section 112(d) of the
Act provides that the EPA shall develop emission standards for
categories of major sources of hazardous air pollutants that
require the application of MACT, "taking into consideration the
cost of achieving such emission reduction and any non-
air. . .health and environmental impacts and energy requirements."
The commenter also noted that in establishing MACT, Congress
instructed the Agency to consider the best performing 12 percent
of the existing sources, or the best performing 5 sources in
categories with fewer than 30 sources. Further, the commenter
pointed out that section 112(d) authorizes the EPA to
"distinguish among classes, types, and sizes of sources" within a
category. The commenter concluded that it is clear, therefore,
that Congress intended that MACT standards be based on technology
applied on a production basis at a significant number of existing
sources.
The commenter claimed that in developing its proposed
standard for aerospace depainting operations, the EPA has failed
to adequately address the following issues:
• the level of HAP control at existing rework facilities
for major commercial airlines;
• the applicability of the standard to rework facilities
for regional airlines and private aircraft;
• the potential adverse economic impacts on commercial
and military facilities; and
• the need to distinguish between the types of military
aircraft that require depainting.
According to the commenter, the shortcomings of the EPA's
analysis and the Agency's determination that a prohibition of HAP
strippers is achievable is flawed and inconsistent with the
requirements of section 112(d).
Two commenters (IV-D-5, IV-D-47) believe that the data in
the record supports the continued use of organic HAP strippers.
To control HAP emissions, commenter IV-D-47 recommended using an
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annual!zed average of methylene chloride stripper per square foot
of aircraft as MACT for depainting operations, in addition to the
non-HAP stripper and media blasting technologies included in the
proposed MACT standard.
Response; The EPA has adopted a provision in the standard
which allows facilities to utilize HAP-containing strippers in
conjunction with control devices. Section 112 requires that the
EPA determine the MACT floor based on the average emissions of
the best performing 12 percent for which the EPA has information.
The EPA made many solicitations to the industry for information
and made decisions based on the information known to the Agency.
7.6.2 Reduced Paint Scheme
Comment: Commenter IV-D-38 stated that several airlines and
the Air Transport Association have submitted information to the
EPA indicating that a reduced paint scheme is not a viable
compliance option for the Agency's proposed depainting provisions
for companies that currently paint their planes. According to
the commenter, the data submitted by these organizations
indicated that a reduced paint scheme would require some aircraft
operators to replace the Alclad surface on aircraft exteriors
that provide part of the corrosion protection system.
The commenter noted that polishing is an alternative method
of corrosion protection for unpainted aluminum surfaces employed
by two of the commercial airlines. The commenter suggested that
both methods, painting and polishing, appear to perform
satisfactorily if properly applied and maintained. However, the
commenter claimed that switching from a painted to a polished
surface presents a significant safety concern.
The commenter also claimed that repeated cycles of
depainting and repainting continually erode the Alclad layer such
that reliance upon protective qualities of the paint itself is
increased. The commenter believes that if painting were ceased,
other protective measures would have to be introduced, such as
reapplication of Alclad, which is cost-prohibitive. The
commenter also claimed that established company logos would
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likely be abandoned with a likely loss of marketing value on the
order of tens of millions of dollars.
The commenter acknowledged that some controversy exists in
the record on the merits of paint versus polishing of aircraft
surfaces for corrosion protection. The commenter stated that,
while they are not in a position to question the merits of either
argument, they believe that sufficient data exist to support the
concern expressed by several commercial airline representatives
about switching from a painted to a polished aircraft.
Therefore, the commenter concluded, while a reduced paint scheme
may be viewed as MACT for new aircraft, it should not be viewed
as a viable option for existing painted aircraft.
Response: A reduced paint scheme was discussed between the
Agency and the industry prior to proposal. The Agency did not
include a reduced paint scheme in the proposed or final rule as a
means of compliance for the depainting standard. However, the
EPA encourages facilities to consider implementing a reduced
paint scheme for new aircraft in order to reduce the total VOC
and HAP emissions from the industry.
7.6.3 Depainting of Private, Corporate, and Small Aircraft
Comment: Commenter IV-D-5 believes that the section 114
questionnaires were selectively distributed since no one within
the private aircraft depainting industry received one. The
commenter stated that the depainting and refurbishing industry,
through the National Air Transport Association (NATA), submitted
a list of 391 facilities and it appears that none of these
facilities was sent a questionnaire. The commenter concluded
that the EPA's sample of 20 from an industry of 2,800 is not
sufficient to draw valid conclusions.
Commenter IV-D-86 stated that the record contains little or
no information on the application of media blasting, non-HAP
chemical strippers, or polishing techniques on general aviation
facilities. The commenter believes that the EPA has not
collected sufficient data to support imposing the depainting
provisions on non-major sources.
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Five commenters (IV-D-5, IV-D-13, IV-D-78, IV-D-83, IV-D-86)
stated that small aircraft are very thin skinned and cannot be
depainted using media blasting.
Commenter IV-D-13 stated that elimination of chemical
stripping would halt the repainting of business aircraft. The
commenter claimed that general aviation manufacturers (Cessna,
Beechcraft, British Aerospace, Falcon, Jet, Gulfstream, Israeli
Aircraft Industries International, Learjet, Raytheon Corporate
Jets, and Piper Aircraft) do not allow or severely limit the use
of media blasting as an approved stripping method. The commenter
pointed out that all general aviation manufacturers recommend
chemical stripping as the preferred method for removing paint
from this class of aircraft.
According to the commenter, the extremely lightweight skins
used in this class of aircraft can be rendered non-airworthy by
media blasting and some manufacturers are now issuing warnings
about this. The commenter concluded by stating that the use of
media blasting would countermand FAA operating requirements which
require general aviation service facilities to follow
manufacturer's recommendations.
Commenter IV-D-5 also stated that the cost of media blasting
equipment is beyond affordability for many small facilities.
Commenter IV-D-86 stated that any suggestion that facilities
maintaining general aviation can use blasting techniques is
inconsistent with the EPA's own economic analysis.
Commenter IV-D-78 stated that small aircraft can readily and
safely be depainted using non-HAP chemical strippers. Commenter
IV-D-78 stated that they supply non-HAP chemical stripping
compounds to a large number of users who routinely use these
products to depaint private, corporate and small commuter
aircraft. The commenter claims that there is no basic
technological difference in the stripping operation between
commercial and private aircraft. According to the commenter, the
same types of paint are routinely used over the same types of
substrates. Commenter IV-D-78 stated that the following
manufacturers of private or corporate aircraft have approved non-
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HAP strippers for use on their aircraft: Beechcraft, Cessna, and
Grumman.
Commenter IV-D-83 stated that coatings which have a cross-
linked polymer structure cannot be stripped using non-HAP
strippers or media blast technology.
The commenter stated that they use cross-linked polymer
coatings for durability and corrosion resistance, not for
appearance. The commenter stated that their experience indicates
that cross-linked coatings are not stripped as easily as other
coatings. The commenter stated that many thin skinned aircraft
are still stripped with HAP-containing materials to prevent
damage to the exterior skins.
Several commenters provided responses to the use of emission
control systems for HAP-containing stripper use at small
facilities.
Commenter IV-D-86 believes that sources engaged in
maintenance of private, corporate, and small commuter aircraft
should have the alternative of implementing simple work practices
and engineering requirements to reduce the emissions from
HAP-containing strippers. The commenter stated that Delta Air
Lines reduced emissions by 35 percent by implementing simple work
practices. The commenter is very concerned about the ability of
small facilities to install carbon adsorption and emission
control equipment.
Commenter IV-D-76 stated that since the statute requires
maximum achievable emission reductions, substituting 99 percent
efficient control devices for HAP emissions from HAP-containing
chemical stripping is only permissible where zero emission
approaches cannot be instituted. This commenter also stated that
they hope that the EPA differentiates between current cosmetic
practices and the needs for proper safety in maintenance in
evaluating the appropriateness of mandating zero emissions
approaches to depainting small aircraft. According to the
commenter, safety issues could justify a less stringent control.
The commenter also stated that zero emissions are justified under
section 112(d) if a change in the coating is for appearance only.
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Commenter IV-D-83 believes that the EPA should extend any
exemption or waiver it may grant to private, corporate, and
commuter aircraft to military aircraft as well.
Response: The docket contains summaries of information
obtained from site visits that were made to private aircraft
depainting industry operations. The final rule's provisions
allow facilities to use the techniques and methods that are
currently being used throughout all aspects of the industry. The
final rule does implement abatement for facilities which use HAP-
containing chemical strippers as the primary technique for
depainting. Any non-HAP depainting method or technique is
acceptable under the standard.
The docket includes information which indicates that dry
media blasting is used by some of the general aviation
manufacturers cited by the commenters. Additionally, it is the
EPA's understanding that the FAA does not require general
aviation to follow manufacturer's recommendations. The EPA also
understands that many facilities choose to follow the
manufacturer's recommendations in order to retain the warranty on
the aircraft. The information collected by the Agency indicated
that many facilities used methylene chloride strippers because
they perform the stripping at a faster rate than some of the
other methods of depainting. Additionally, the EPA has exempted
non-major sources from the NESHAP which should eliminate small
businesses from coverage under the NESHAP. The EPA will issue a
Aerospace CTG to address VOC emissions from non-major sources.
7.7 ORGANIC HAP EMISSIONS
7.7.1 General Comments
Comment: Two commenters (IV-D-29, IV-D-35) stated that many
depaint technologies emit small quantities of organic HAP. The
commenters noted that pulsed light technologies such as laser,
flashlamp, and pinch-lamp, as well as abrasive methods have the
potential of emitting organic HAP due to chemical reactions in
the volatilized paint. Commenter IV-D-35 suggested that the
intent of the EPA would be better achieved by disallowing
materials which contain organic HAP based on an MSDS. The
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commenter recommended that users be allowed to rely upon the
organic HAP content listed on the MSDS to determine compliance
with the rule.
Commenter IV-D-29 claimed that in all of their pre-proposed
rule discussions with the EPA, the Agency had asserted that
depainting should not result in any organic HAP emissions from
the chemical stripper. The commenter pointed out that the
proposed rule incorporated a prohibition on all organic HAP
emissions from the depainting operation. The commenter claimed
that this change is not acceptable because it makes literal
compliance impossible.
The commenter recommended the following revision of
§63.746(b), which they believe restores the original intent to
regulate the HAP content of the stripping media. Thus,
§63.746(b)(1) should be revised as follows:
"§63.746(b)(1) Organic HAP emissions. Except as provided
in paragraph (b)(3) of this section, each owner or operator
of a new or existing aerospace depainting operation subject
to this subpart shall emit no not use chemical strippers
that contain any organic HAP reported as exceeding the OSHA
de minimis threshold concentration as defined by 29 CFR
S191 u . 1200 . Li.iwfiu trie de^&inting op^irs. tion.
Commenter IV-D-35 recommended that §63.746(b)(1) be revised
to read as follows:
"Organic HAP emissions. Except as provided in paragraph
(b)(3) of this section, each owner or operator of a new or
existing aerospace depainting operation subject to this
subpart shall not apply depaint materials which contain
organic HAP as identified in the MSDS."
Response: The docket contains information that the abrasive
technologies noted by the commenter are usually accompanied by an
emissions capture device attached at the point of coating removal
and that the organic HAP emissions are very small. Therefore,
the final rule does not regulate these emission sources.
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7.7.2 Emissions Control
Comment: Nine commenters (IV-D-5, IV-D-27, IV-D-42,
IV-D-47, IV-D-77, IV-D-80, IV-D-81, IV-D-84, IV-D-86) recommended
that HAP-containing chemical stripper usage be retained in the
final rule and that the rule specify an emissions limit when
emissions capture and removal systems are used.
Commenter IV-D-38 stated that control of organic HAP
emissions from depainting operations currently is not performed
at either commercial or military facilities, and is likely to be
prohibitively expensive. Nevertheless, the commenter pointed
out, the record contains a description of one project in which
emissions of methylene chloride from the depainting operation and
VOC emissions from a coating operation will be controlled by a
UV/ozone system with combined scrubber and carbon adsorbers.
The commenter also pointed out that data were submitted by
Delta Air Lines which indicate that significant emission
reductions can be achieved through relatively simple engineering
and work practices. The commenter stated that Delta reported a
35 percent reduction in fugitive emissions through the use of
waste-stripper troughs. The commenter stated that the troughs
are placed around the aircraft and plastic is draped from the
aircraft to one side of the trough. The troughs collect the
waste stripper which is pumped directly into waste drums.
Moreover, the commenter noted that the design of the maintenance
facility allows full access to the aircraft, thereby reducing
stripping times significantly. As a result of these measures,
the commenter noted, Delta reported an average emission rate of
0.05 Ib of methylene chloride or less per square foot of aircraft
surface. The commenter stated that Delta's emission rate is one
half or less of that reported by Robins AFB, which the commenter
believes reflects a more efficient depainting operation and
stripper formulations.
The commenter suggested that, rather than specifying a
control level, the EPA may wish to consider HAP control
requirements from depainting operations based on (1) equipment
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(i.e., carbon adsorption) and work practices, ojc (2) an
emission/loss rate derived from the available data.
Commenter IV-D-81 stated that the option of installing a
control device in depainting operations is essential for everyone
in the aerospace industry. The commenter stated that the EPA
said from the onset on the NESHAP negotiations that if compliant
coatings and solvents were used by a company, control devices
would always be an option of control. The commenter stated that
the EPA stipulated that a 81 percent control efficiency
(90 percent capture, 90 percent destruction) would be required as
a minimum for any instance requiring a control device.
Five commenters (IV-D-80, IV-D-81, IV-D-83, IV-D-84, IV-D-
86) supported the 81 percent control efficiency requirement.
Commenter IV-D-84 stated that an 81 percent total capture
and control efficiency appears to be an achievable level of
control of HAP emissions from depainting operations, according to
information from the U.S. Navy and the aerospace industry.
Commenter IV-D-78 stated that the use of control devices to
control emissions from HAP-containing chemical strippers is
generally regarded as impractical with current technology. The
commenter suggested that this is because all HAP-containing
chemical strippers are based on methylene chloride as the
principal solvent. According to the commenter, methylene
chloride, due to its small size and high volatility, is poorly
absorbed by activated carbon, and has a very short breakthrough
time. The commenter claimed that the low adsorption efficiency
makes it very difficult to concentrate methylene chloride vapors
sufficiently to destroy the methylene chloride, either by
incineration or other technology.
Commenter IV-D-77 stated that carbon adsorption in
combination with catalytic oxidation (incineration) as a control
option for HAP emissions from depainting operations can be
designed to easily achieve a 99 percent plus reduction in low
concentration streams. In particular, the commenter stated that
systems are currently employed to treat streams from 35,000 scfm
to in excess of 350,000 scfm, reflecting that the technology can
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be used as an effective control strategy for depainting
operations for large commercial and military aircraft as well as
smaller aircraft.
Based on technological concerns, some commenters (IV-D-80,
IV-D-84, IV-D-86) do not believe that a MACT standard requiring a
carbon adsorber/catalytic incinerator combination with 99 percent
control efficiency can be considered "achievable" under section
112(d)(2). Commenter IV-D-86 pointed out that information
submitted to the EPA from Tyndall AFB indicated that even a 95
percent control efficiency of solvent depainting emissions could
not be attained on a long-term basis in practical applications.
Two commenters (IV-D-81, IV-D-86) believe that a 99 percent
removal efficiency is not economically feasible.
One commenter (IV-D-35, IV-D-83) suggested that organic HAP
should be allowed if controlled with at least an 81 percent
control efficiency and emissions are not more than an equivalent
of 50 gallons of stripper per aircraft.
Three commenters (IV-D-29, IV-D-35, IV-D-81) believe that if
the EPA would allow control devices and require that facilities
stay within the level of emissions that would result from the use
of the 26 and 50 gallon spot-stripping exemption, then the
industry would be provided with a workable option.
Two commenters (IV-D-35, IV-D-29) recommended that the
following be added to §63.746(d):
"Control of organic HAP strippers. Each owner or operator
of a new or existing depainting operation shall have an
option to use organic HAP stripper if the control device
maintains a minimum of 81% organic HAP control efficiency
and does not emit more than an equivalent of 50 gallons of
prganic HAP stripper per aircraft."
Response: The EPA has adopted the commenter's
recommendations and included a provision in the standard which
allows the use of HAP-containing chemical strippers used in
conjunction with an emission control system. Facilities which
choose to use HAP-containing chemical strippers will be required
to conduct their operations in enclosed areas. Additionally, for
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existing control systems, organic HAP emissions must be captured
and controlled at an overall system efficiency of 81 percent.
For new control systems, emissions must be controlled at 95
percent.
Only facilities using non-HAP depainting methods or
techniques may use the 26-gallon or 50-gallon spot stripping and
decal removal exemption.
Comment: Commenter IV-D-5 stated that the use of the term
"no" in proposed §63.746(b)(1) exemplifies the inadequate use of
the scientific process for this proposal in determining the
facts. The commenter asked whether "no" means "zero," or is it
less than current detectable limits or any future detectable
limits? The commenter pointed out that the use of 1 percent
could mean "no" in a particular situation.
Another commenter IV-D-42 believes that compliance with
§63.746(b)(1) will depend on measurement instrument sensitivity
and may be influenced by trace contaminants in depainting
materials.
A third commenter IV-D-30 suggested that, since analytical
methods are rarely absolute, the EPA should consider imposing a
minimum detection limit for compliance with this requirement.
Commenter IV-D-31 expressed support for the zero emissions
standard for depainting operations. The commenter stated that
the EPA is correct in recognizing that the wide variety of
available techniques with zero emissions make a zero emissions
standard achievable in this area.
Response: The HAP content of chemical strippers shall be
determined from manufacturer's formulation data (i.e., MSDS).
7.7.3 Emissions during periods of equipment malfunction
Comment; Commenter IV-D-31 recommended that the EPA limit
sources to 15 days annually of HAP compound depainting in the
event of an equipment failure. Generally, the commenter believes
that if the depainting system fails, the source should replace
the system or use non-HAP chemicals, rather than go back to HAP-
containing stripper. The commenter claimed that most
malfunctions should be repairable (or the system replaceable)
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within a day. According to the commenter, allowing too much time
removes the incentive to repair the system as quickly as
possible. The commenter stated that allowing a 15-day maximum
period only seems reasonable if using the entire period puts the
operator in some danger of having to slow down operations if the
problem occurs again without a backup. The commenter believes
manufacturers should have non-chemical backups if they anticipate
repeated problems.
A second commenter (IV-D-11) stated that, for periods of
non-chemical based depainting equipment malfunction, replacement
parts can usually be obtained and installed within 5 working
days. The commenter believes that most facilities stock spare
parts and that the 45 days allowed annually for equipment failure
could be reduced by adding a requirement that specifies that a
sufficient number of parts be kept on site. The commenter
concluded by stating that the annual limit of 45 days would allow
about nine periods of malfunction of nonchemical-based depainting
equipment and is enough time allowance to facilitate estimated
repairs as well as any incidental repairs.
Commenter IV-D-35 believes that a 14-day period is
justifiable and realistic. Additionally, the commenter
recommended that 14-day periods include downtime for extended
scheduled equipment maintenance. The commenter pointed out that
the Air Force currently uses HAP-containing stripper over a 13
flow (work) day period to depaint E-3 aircraft. The commenter
stated that this period is consistent with the time required to
chemically depaint other large military aircraft using HAP-
containing strippers.
Commenter IV-D-35 also stated that the limitation on
substitute materials is unclear and leads to technical problems
associated with engineering qualification of substitute
materials. The materials available, either on-site or in the
marketplace, which minimize organic HAP emissions, may not be
appropriate (qualified) for aircraft application. According to
the commenter, if the limitation on substitute materials is not
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removed, then the EPA needs to clarify "available" to mean
"qualified materials which are available on-site."
Commenter IV-D-35 suggested that due to the complexity of
the Large Aircraft Robotic Paint Stripping (LARPS) system being
implemented at the Oklahoma City Air Logistics Center in April
1995, the LARPS system should serve as the baseline for the
annual number of days that a HAP-containing stripper may be used
when equipment is not functional. The commenter stated that the
total number of days allowable for HAP-containing stripper use
due to equipment malfunction and scheduled equipment maintenance
should be calculated as follows:
Annual Limit Days = (365 work days/year x (1-0.85)) +
14 maintenance days = 68.75 days.
Response: The EPA has not stated in the rule that HAP-
containing chemical strippers may be used during periods of
equipment malfunction and maintenance. The rule states in
§63.746(b)(2), "...During periods of malfunctions of such
equipment, each owner or operator may use substitute materials
during the repair period provided the substitute materials used
are those available that minimize organic HAP emissions." This
statement should not be construed by the industry to mean that
each facility may use HAP-containing chemical strippers without
any abatement or without work practices designed to minimize the
emissions from this type of stripper. The intention in the rule
was not to limit facilities to a particular method or technique
of depainting during periods of equipment malfunction. The EPA
is providing facilities with the flexibility to determine what
constitutes the phrase "minimize organic HAP emission."
Additionally, since the EPA has adopted a provision which allows
a facility to use HAP-containing chemical strippers, the number
of days that a facility may use organic HAP-containing strippers
without complying with the emission limits in the standard has
been revised to 15 days annually. Also, a facility may always
use any non-HAP technique or method during periods of equipment
malfunction without any restriction on the number of days that
these techniques may be used.
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7.8 INORGANIC HAP EMISSIONS
Comment: Commenter IV-D-29 recommended the following
revision for §63.746(b)(2):
"§63.746(b)(2) Where non-chemical based depainting
equipment is used to comply with paragraph (b)(1) of this
section, either in total or in part, each owner or operator
shall operate and maintain the equipment according to the
manufacturer's instructions specification or local specified
operating procedures. During periods of malfunctions of
such equipment, each owner or operator may use substitute
materials or methods during the repair period provided the
substitute materials used are those available that minimize
organic HAP emissions. In no event shall substitute
materials be used for longer than 14 consecutive days,
unless such materials are organic HAP-free."
Commenter IV-D-35 recommended that §63.746(b)(2) be revised
to read as follows:
"Where non-chemical based equipment is used to comply with
paragraph (b)(1) of this section, either in total or in
part, each owner or operator shall operate and maintain the
equipment according to manufacturer's specification or
locally specified operating procedures. During periods of
malfunctions of such equipment, each owner or operator may
use substitute materials during the repair period. Each
owner or operator shall minimize organic HAP emissions from
the substitute materials or methods during the repair or
maintenance period. In no event shall substitute materials
be used for longer than 14 days, unless such materials are
organic HAP-free."
The commenter stated that in many cases existing or new
equipment has inadequate or incomplete operating instructions
which require additional instructions to ensure proper
operations, safety, and compliance with environmental laws. The
commenter noted that the rule provides for an allowance of 50
gallons of HAP stripper for spot stripping and decal removal per
aircraft per facility. The commenter claimed that the facility
7-35
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must be allowed to utilize this exemption during any periods when
non-chemical based equipment malfunctions, without the
limitations proposed by the EPA.
A second commenter IV-D-5 stated that requiring non-
chemical-based depainting equipment to be operated and maintained
according to manufacturer's specifications is not an adequate
control since the manufacturer's specifications may not be
adequate and because everyone does not operate in a responsible
manner. The commenter was concerned that large amounts of
inorganic HAP could be introduced into the environment.
Response: The EPA's experience is that requiring equipment
to be operated according to the manufacturer's specifications is
sufficient control on the operation and maintenance of many types
of equipment that do not have universally accepted operational
standards. The EPA recognizes that locally specified operating
instructions may provide an opportunity for facilities to
maximize the performance of their equipment based on their own
particular operating environment. The EPA does not anticipate
any enforcement problems associated with this requirement.
Additionally, a new provision has been added to the rule which
requires a facility to report the operational procedures that are
followed when a facility varies from the procedures specified by
the equipment manufacturer.
Comment: Commenter IV-D-29 believes that the intent of the
rule was never to regulate trace amounts of inorganic HAP from
depainting operations, which the commenter stated is consistent
with industry data collected on depainting operations. According
to the commenter, the airborne inorganic HAP to be controlled are
those omitted from the removal of paint which is reported to
contain inorganic HAP at levels exceeding the OSHA de minimis
threshold concentration, as defined by 29 CFR §1910.1200.
The commenter, therefore, recommended the following
revisions to §63.746(d):
"(d) Inorganic HAP emissions. Each owner or operator of a
new or existing depainting operation subject to this subpart
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that involve the depainting of coatings containing inorganic
HAP reported as exceeding the OSHA de minimis threshold
concentration as defined by 29 CFR S1910.12QO. and that
generates airborne particulate emissions from the coating
being removed that contain inorganic HAP shall comply with
the requirements specified in paragraphs (d)(1) through
(d)(4) of this section."
Response: The EPA believes that adopting the commenter's
recommendation would require facilities to do additional testing
to determine the concentration and content of the inorganic HAP.
Therefore, the EPA has not incorporated the commenter's
recommendation into the final rule. Furthermore, final rule will
control particulate emissions through workplace standards instead
of specifying control efficiencies or establishing de minimis
concentration exemptions.
Comment: Commenter IV-D-5 stated that it is significant
that the solid waste generated by a methylene chloride remover
will in most cases be less than the solid waste generated by dry
blasting techniques. According to the commenter, an air filter
system would not be necessary when stripping with the methylene
chloride remover because the inorganic HAP probably would not
become airborne.
Response: The commenter is correct in stating that the
solid waste generated by methylene chloride remover is less than
the solid waste generated by media blasting. However, the
quantity of solid waste generated is not an indicator of the
quantity of HAPs emitted from the process. In many cases, a
large percentage of the used media -can be recycled through the
process.
7.9 PARTICULATE CONTROL
7.9.1 99 Percent Control Efficiency
Comment: Three commenters (IV-D-29, IV-D-35, IV-D-37)
stated that the 99 percent control efficiency proposed for
inorganic emissions is not an achievable limit. Two commenters
(IV-D-29, IV-D-37) questioned the legal sufficiency of proposed
§63.746(d)(2), a 99 percent inorganic HAP filtration efficiency
7-37
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for media blasting depainting operations. The commenters noted
that section 112(d)(3)(B) of the amended Act requires that if a
subcategory contains fewer than 30 sources, the MACT floor should
be determined based on the average level of control achieved by
the best controlled 5 sources.
According to commenter TV-D-29, if the sole source that
constitutes the MACT floor in this case is within its own
separate subcategory (e.g., if that facility uses blast
depainting on relatively small assemblies), it is not appropriate
to extend the same control efficiency claim to a hanger-sized
depainting operation.
Three commenters (IV-D-5, IV-D-29, IV-D-37) pointed out that
the Agency adopted, as the MACT standard, the filter efficiency
reported by the top-performing single facility out of seven
sources that provided information regarding media blast
depainting. Commenter IV-D-37 remarked that no differentiation
appears to have been made by EPA of the type and amount of
mechanical depainting technology employed by these seven sources.
Five commenters (IV-D-5, IV-D-29, IV-D-35, IV-D-37, IV-F-1)
pointed out that the control efficiencies reported on the section
114 questionnaire responses were based on manufacturers' data and
not source testing.
Commenter (IV-F-1) stated that the manufacturers did not use
an ASHRAE test to substantiate the control efficiencies reported
on the section 114 responses. According to the commenter, when
the manufacturers did use an ASHRAE testing method, the particle
size distribution was not constant, and the manufacturers did not
match particle size distribution to the claimed removal
efficiency. Commenter IV-D-37 believes that the filter
manufacturer efficiency claims are based on ability to capture
particulates of a certain size at controlled air flow rates.
Commenter IV-D-29 stated that, while the rule requires 99
percent overall control of all emissions from depainting (overall
control efficiency), the data submitted to the EPA and upon which
this requirement was based only reflected control of those
emissions that were actually captured (removal efficiency). Two
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commenters (IV-D-29, IV-D-52) stated that overall control
efficiency can only be determined when "capture efficiency," as
well as removal efficiency, is accounted for. According to
commenter IV-D-35, the only emission testing conducted on a PMB
process using Method 5 was conducted on August 10-12, 1994, by
CH2M Hill at McClellan AFB, CA. The commenter provided a summary
of the testing process and the results which indicated control
efficiencies ranging from 74 to 93 percent. According to the
commenter, without process testing to establish both particle
size distribution and the concentration distribution of inorganic
HAP, there is no way to know if a 84 percent efficient
particulate control system would provide significantly less
reduction in inorganic HAP than a system with 99 percent
efficiency.
Two of the commenters (IV-D-23, IV-D-33) stated that
collection of samples upstream of controls for the Method 5
determination may be difficult or impossible in many cases.
Three other commenters (IV-D-11, IV-D-27, IV-D-29) also
expressed concerns over the fact that particulate size
specifications were not listed.
Commenter IV-D-27 recommended either clarification regarding
particle size in relation to the control efficiency (because an
efficiency rating cannot be placed on a baghouse or dry filter
without referencing a particle size) or a rewording of the text.
Commenter IV-D-29 believes that the particulate size varies,
depending upon the mechanical depainting technology being used.
The commenter maintained that in order to set a numerical MACT
floor, the EPA must obtain results of actual filtering operations
and set the control efficiency based upon the applicable
particulate profile (depainting technology) being used.
Commenter IV-D-11 believes that a performance standard based
upon outlet grain loading is more appropriate than using a
control efficiency standard. The commenter proposed that an
outlet grain loading of 0.01 grain per standard cubic foot
(gr/scf) should be the standard. According to the commenter,
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this would allow for a wide variety of abrasive blast media to be
used while minimizing HAP and non-HAP emissions. The commenter
supports the 99 percent control efficiency standard and noted
that particulate control equipment vendors have routinely
submitted laboratory and field test results verifying the level
of control required.
Commenter IV-D-31 recommended that the final rule require
high efficiency particulate filters when inorganics are present
and that, at a minimum, a 99 percent reduction in PM10 be
required, rather than a 99 percent reduction of particulate in
general.
Two commenters (IV-D-5, IV-D-32) believe that a distinction
must be made between (1) the total quantity and throughput of
material used and (2) the particulate content of the air that
actually enters the filter system. Commenter IV-D-5 was
concerned that the 99 percent control requirement does not
account for the concentration of emissions entering the filter,
specifically hexavalent chromium emissions. Commenter IV-D-32
requested that the rule clarify that the 99 percent figure
applies to the total quantity of particulate in the operation,
and not just the quantity that reaches the filter.
Commenter IV-D-35 recommended that particulate filter
control be applied only to dry media blasting.
Commenter IV-D-37 concluded that the Agency should adopt the
same standard for depainting filters as proposed in §63.745(f) of
the NESHAP for control of inorganic HAP from primer and topcoat
application operations; i.e., a general description of the
required control device combined with monitoring requirements.
Commenter IV-D-32 recommended that the EPA modify the
requirement that air be passed through a "particulate filter" to
read that it be passed through a "particulate control system."
Commenter IV-D-27 recommended that §63.746(d)(2) be revised
as follows:
"Pass any air stream removed from the hangar enclosed area
through a particulate filter with a particulate control
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efficiency of at least 99 percent before exhausting to the
atmosphere."
Commenter IV-D-35 recommended that §63.746(d)(2) be revised
to read as follows:
"Pass any air stream removed from the hangar through a
particulate filter before exhausting to the atmosphere."
Two commenters (IV-D-43, IV-D-52) recommended that the
regulation offer local control districts the flexibility to
propose alternate monitoring requirements from inorganic
depainting regulations. Commenter IV-D-43 noted that their
district has permitted a number of sources for the depainting of
aircraft, commercial and military, using plastic media blasting
and that these operations are conducted in an enclosed hangar
with large filter banks for the capture of particulate matter.
For the parametric monitoring of filter media, the commenter
requires the following:
1. Installation of differential pressure gauge across the
filter banks;
2. Replacement of the filter media when the pressure drop
exceeds a pre-set amount;
3. Filter media at least two inches thick;
4. Recording the frequency of filter media changes; and,
5. An initial source test to determine the particulate
emission rate from the exhaust stacks.
Commenter IV-D-33 recommended that alternative methods to
demonstrate particulate emission reductions for depainting
operations be allowed, such as:
1. equipment and filter specifications,
2. certification of manufacturer's equipment, and/or
3. setting a de minimis exhaust concentration.
Commenter IV-D-35 recommended that the EPA delete
§63.750(1), revise §63.746(d) and (d)(2), and add paragraph
(d)(5) as follows:
"(d) Inorganic HAP emissions. Except as provided in
paragraph (d)(5) of this section, each owner or operator of
a new or existing dry media blasting depainting operation
7-41
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subject to this subpart that generates airborne particulate
emissions that contain inorganic HAP shall comply with the
requirements specified in paragraphs (d)(1) through (d)(4).
(2) Pass any air steam removed from the hangar through a
particulate filter with a pairticulate control efficiency of
at least 99% before exhausting to the atmosphere.
(5) Depainting methods in which particulate control is
built into the stripping apparatus at the emission source is
exempt from paragraphs (d)(1) through (d)(4) of this
section. Depainting methods other than dry media blasting
are exempt from paragraphs (d)(2) through (d)(4) of this
section."
Response: The EPA proposed a 99 percent control efficiency
requirement based on the top performing emission sources. The
top four sources reported control efficiencies equal to or in
excess of 99 percent. The fifth source reported a 95 percent
efficiency based on engineering judgment. Three of the top four
performing facilities reported efficiencies based on
manufacturers' claims. The EPA also acknowledges that a
particulate size was not stated in the proposed rule, nor was an
emissions concentration limit specified.
The EPA believes that significant quantities of emissions
can be controlled by allowing facilities to operate the filter
system according to the manufacturer's specifications in lieu of
requiring a 99 percent control efficiency. The EPA acknowledges
that there are inherent difficulties associated with determining
compliance, since particle size has not been correlated with
specific values of control efficiency. Therefore, the EPA has
deleted the 99 percent control efficiency and the Method 5
testing requirement. The final rule requires facilities to
operate and maintain their particulate filter systems in
accordance with work practice specifications and according to
manufacturer's recommendations for dry particulate filters and
waterwash booths used in conjunction with depainting operations.
Waterwash booths will be monitored by visual inspection of
the water curtain and monitoring the water flow rate. If gaps
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are present in the water curtain or the flow rate is outside of
the parameters established by the manufacturer, the final rule
requires the operator to shut down the operation immediately and
take corrective action. For dry filter systems, the EPA has
adopted the following:
1. Installation of a differential pressure gauge across
the filter banks;
2. Replacement of the filter media when the pressure drop
exceeds or falls below the manufacturer's
recommendations; and,
3. continuously monitor the pressure drop across the
filter.
Additionally, the EPA is currently investigating a number of
options with respect to implementing compliance options for
particulate filters. Test methods are being developed which will
allow filter manufacturers to qualify their filters as EPA-
approved. The Agency would then require affected sources to use
EPA-approved filters in the control devices used to capture the
particulates resulting from the depainting operations. The EPA
must determine the best way to implement the provisions and will
issue a supplemental proposal to the NESHAP that will solicit
public comments on a provision that the Agency deems to be
enforceable and guarantees the public's safety.
7.9.2 Waterwash Booths
Comment: Commenter IV-D-29 stated that they previously
presented the EPA with information on waterwash booths for
control of inorganic HAP emissions from painting operations. The
commenter believes that this same information supports the use of
waterwash booths for the control of inorganic HAP emissions from
depainting operations. The commenter included the information
sent to the EPA with their comments on the proposed rule.
The commenter recommended that proposed §63.746(d)(2)
through (4) be revised as follows:
" (2) Pass any the air stream removed from the hangar
tXilT OU-H^il ck. t/cl Irt JL CU.-L cl L, GX, 1 x L. S IT Wl U.JT1 ct COllu.1. O-L SCClClcliCy Gt ck.t
7-43
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J.&&£c j3 p^ir c^iit.Ju"^Loir^ GjdiALLScmc[to trie&Lx^c/fipri&r £ tnrougn
either dry particulate filters or a. waterwash system before
exhausting to the atmosphere.
\j) cjoritmuou£J._y itAomtoir tn£ pir£ssuir&Qirop&CITOSS ui\^;;
particulate filter. Each owner or operator using
particulate filters shall daily monitor the pressure drop
across the particulate filter. Each owner or operator using
a waterwash system shall either (1) perform a daily visual
inspection of the water path for continuity/flow
characteristics, or (2) where visual inspections are not
applicable, (a) monitor water flow meter readings daily, or
(b) adopt the booth manufacturer's maintenance procedures.
(4) If the pressure drop, as recorded pursuant to
§63.752 (e) (5), is outside the limit(s) specified by the
filter manufacturer, shut down the operation immediately and
take corrective action. If (1) the water path fails the
visual continuity/flow characteristics check, or (2) where
visual inspections are not applicable, the daily flow meter
requirements show an interruption in flow, or the booth
manufacturer's maintenance procedures have not been
performed as scheduled, the operation must be shut down
immediately and take corrective action. The operation shall
not be resumed until the pressure drop is returned to the
1imit(s)—specified by—the manufacturer non-conformance is
corrected."
Response: The EPA has adopted a provision that allows the
use of waterwash booths for particulate control from depainting
operations. The EPA has included the following provisions in the
final rule for waterwash booths: (1) if the water path fails the
visual continuity/flow characteristics check, or the flow meter
requirements show a disruption in flow, or the booth
manufacturer's maintenance procedures have not been performed as
scheduled, the operation must be shut down immediately and
corrective action taken; and (2) the operation shall not be
resumed until the waterwash flow is within the limit(s) specified
by the booth manufacturer.
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7.9.3 Monitoring Requirements
Comment: Commenter IV-D-5 stated that the entire proposed
monitoring process is all paperwork with no actual emissions
monitoring. The commenter believes that the negative
environmental impact through labor and recordkeeping material
costs could be greater than the 2.6 percent HAP emissions from
current methylene chloride methods of depainting aircraft.
Response: The commenter did not provide any specific
support for their comment.
Comment: Commenter IV-D-33 supported the provision that
requires the operator to shut down the depainting operation
immediately if the pressure drop across the particulate filter is
exceeded. Two commenters (IV-D-11, IV-D-43) recommended that in
the case of an exceedance, the facility should stop operation at
the end of the shift, replace the filters, and record this
activity. Commenter IV-D-11 stated that subsequent shifts that
do not meet the standard should constitute a violation.
Commenter IV-D-43 recommended that the facility install an alarm
system to indicate when the pressure drop has been exceeded.
Response: The EPA will not allow facilities to continue
using any depainting method that generates airborne inorganic HAP
when the control device is not functional. For the majority of
facilities using media blasting techniques, this means that when
the pressure drop exceeds or falls below the manufacturer's
recommendations, the depainting operation must be shut down. The
docket contains information which indicates that the pressure
drop is a parameter that does not fluctuate dynamically. The EPA
believes that most cases of pressure exceedance occur due to a
lack of proper monitoring. Therefore, any facility that
continues to operate depainting operations when the pressure drop
parameter exceeds the manufacturer's specifications will be
considered in violation of the standard. Additionally, for
facilities that choose a waterwash system for particulate
control, the facility must also be shut down when the particulate
control system is not fully operational.
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7.9.4 General Comments
Comment: Commenter IV-D-27 recommended the following
revision to paragraph §63.746(d)(1):
» (d) * * *
(1) Perform the depainting operation in an enclosed hangar
area."
According to the commenter, many small parts are depainted
in an enclosed controlled environment.
Response: The EPA has adopted and incorporated the
commenter's recommendation into the final rule.
Comment: Commenter IV-D-35 recommended that §63.746(d) be
revised to read as follows:
"Inorganic HAP emissions. Except as provided in paragraph
(d)(5) of this section, each owner or operator of a new or
existing dry media blasting depainting operation subject to
this subpart that generates airborne particulate emissions
that contain inorganic HAP shall comply with the
requirements specified in paragraphs (d)(1) through (d)(4)
of this section."
The commenter stated that other non-chemical depainting
operations such as mechanical sanding and pulsed-light
technologies have much lower emissions than dry media blasting.
The commenter believes that requiring the same control efficiency
for these technologies is counterproductive.
Commenter IV-D-35 pointed out that the data provided to the
EPA on the section 114 questionnaire reported control
technologies on facilities used for plastic media blasting and
wheat starch blasting. Two commenters (IV-D-29, IV-D-35) stated
that other depainting technologies, such as water blasting, C02
blasting, Flashjet, and laser have different emission
characteristics and control technologies which have not been
evaluated. Both commenters suggested that these other
technologies may not require filtration of the entire depaint
hangar to control particulate emissions.
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Commenter IV-D-29 believes that the final rule should
provide for the use of alternate control approaches and
recommended that §63.746(d)(1) be revised as follows:
"(1) Perform the depainting operation in an enclosed hangar
or with equipment which allows for capture of paint debris
and fine particulates from the depainting operation at the
source."
Response: The EPA concurs with the commenter's analysis and
has incorporated a revision in the standard that specifies that
particulate control devices apply to media blasting only. The
EPA added this provision because dry media blasting operations
appear to be the only technology that releases substantial
quantities of inorganic HAP into the air.
7.10 SPOT STRIPPING EXEMPTION
Comment: Commenter IV-D-38 noted that the proposed rule
would prohibit the use of paint strippers containing HAP except
in the cases of spot stripping, decal removal, and periods of
non-chemical based depainting equipment malfunction. The
commenter believes that it is not clear from the information
available in the record that the proposed 50-gallon exemption for
spot stripping of military aircraft would allow these facilities
to continue to perform their depainting operations. Moreover,
the commenter claimed that use of such an exemption is not
desirable from a production standpoint because it requires moving
the aircraft between the PMB facility and the chemical strip
facility. The commenter suggested that it also is likely that
remasking of the aircraft would be required for each process.
Commenter IV-D-74 believes that the spot-stripping exemption
is unnecessary. According to the commenter, any paint residue
not completely removed by the non-HAP stripper has been found in
practice to be readily removable with a minimum amount of hand
detail work. The commenter recommended that the spot-stripping
exemption be eliminated from the NESHAP.
Commenter IV-D-74 stated that the spot-stripping allowance
should be reduced and that it be expressed as an allowance per
square foot of total aircraft surface area so that smaller
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aircraft (which comprise 96 percent of the domestic aircraft
fleet) would still be effectively included in the NESHAP. The
commenter claimed that to do otherwise would allow the
unnecessary continued emission of tons of methylene chloride and
other HAPs into the atmosphere.
Another commenter IV-D-31 asked for a "reasoned" explanation
of why the spot stripping and decal exemption, if retained in the
final rule, is higher for military aircraft than for commercial
aircraft.
Several commenters expressed additional opinions on this
proposed exemption. Two commenters (IV-D-2, IV-D-23) were
concerned that the 26-gallon exemption of HAP-containing chemical
strippers for spot stripping and decal removal could be employed
as a defense to an enforcement action.
Commenter IV-D-23 recommended that the decision on the
technical feasibility be left to the permitting agency and any
authorization for the use of HAP-containing chemical strippers
for spot stripping be contained in the title V permit.
Commenter IV-D-31 recommended that the amount of allowable
HAP containing stripper be limited to less than 26 gallons
annually for each facility (not each aircraft) both military and
commercial. According to the commenter this exemption, if
justifiable at all, should be justified by occasional equipment
failure. However, according to the commenter, the proposal
structures it in such a way as to allow repeated failures to go
unrepaired.
Commenter IV-D-35 supported the 50-gallon spot stripping and
decal removal exemption for military aircraft.
Commenter IV-D-29 stated that the proposed 26- and 50-gallon
exemptions for commercial and military aircraft do not reflect
the needs and practices of OEMs.
According to the commenter, media blasting cannot be
performed in existing paint hangars, because non-chemical
blasting techniques generate particulates. The commenter
believes that the cost of constructing a new hangar for
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depainting is not economically feasible considering the low
number of aircraft depainted by this portion of the industry.
The commenter believes that for OEMs, the spot stripping
exemption should be based on each vehicle produced, not
depainted.
The commenter, therefore, recommended the following revision
to §63.746(c):
"§63.746{c) Spot stripping and decal removal. Each owner
or operator of a new or existing depainting operation
subject to this subpart shall not, on an annual average
basis, use more than 26 gallons of organic HAP-containing
chemical strippers per commercial aircraft aerospace vehicle
or more than 50 gallons of organic HAP-containing chemical
strippers per military aircraft aerospace vehicle for spot
stripping and decal removal. For OEM's the 26/50 gallon
limit is based on aircraft produced per year."
Two commenters (IV-D-38, IV-D-47) believe that the existing
proposal for a spot stripping/decal removal exemption needs to be
revised and expanded. The commenters stated that the exemption
would not allow the use of a HAP stripper on the main fuselage of
the aircraft. Commenter IV-D-47 suggested that the exemption be
revised to allow an annual 50 gallon per aircraft limit for any
type of stripping. Commenter IV-D-38 stated that the 26- and 50-
gallon exemptions should be increased. Both commenters (IV-D-38,
IV-D-47) suggested that a broader exemption would provide
flexibility to facilities as they comply with the standard
without risking excessive penalties for non-compliance.
Response; The exemption for military use was based on the
need to depaint the "leading edge" of the B-52 wing sections with
chemical strippers. This area equals 870 ft2. The B-52 has a
total surface area of 16,000 ft2. The 50-gal exemption is based
on information supplied by Tinker AFB, where they use 0.6271 Ib
stripper/ft2. The 50 gal exemption allows 5.5 percent of the
exterior surface to be stripped with chemical strippers.
Facilities choosing to use HAP-containing strippers to
depaint the entire outer surface of the aircraft may not use the
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26/50 spot stripping exemption. When HAP-containing strippers
are used to depaint the entire outer surface of an aerospace
vehicle or component, their is no technical justification why all
of the emissions from the stripping operation cannot be
controlled.
7.11 GENERAL COMMENTS
Comment: Three commenters (IV-D-38, IV-D-47, IV-D-46)
expressed concern with the use of non-HAP stripper formulations
and the potential for an increase in the release of VOC in urban
areas. The commenters stated that while methylene chloride is
listed as an exempt VOC under the Federal provisions for ozone
attainment, the active ingredients of non-HAP strippers generally
are not. As a result, commenter IV-D-38 proposed that facilities
wishing to use one of these products may encounter VOC permitting
problems. This commenter claimed that this has reportedly been
the experience of an Air Force base in California where the local
air quality management district is concerned about emissions
resulting from wind or elevated temperatures. Two commenters
(IV-D-38, IV-D-47) believe that for many facilities, increased
VOC emissions may make it impossible to comply with existing
state ozone rules for the aerospace industry.
Commenter IV-D-47 suggested that, while the use of non-HAP
strippers would have the effect of reducing methylene chloride
(DCM) emissions from depainting operations, it also would
increase the emissions of other chemicals used in the
reformulated, non-HAP chemical strippers used to comply with the
rule. The commenter claimed that the increase in emissions would
be exacerbated since non-HAP strippers often require longer
stripping times than methylene-chloride based strippers.
Commenter IV-D-46 stated that the current definition of VOC
is based on regulations originally developed for paints, and is
not really relevant for many other solvent containing materials.
The commenter also stated that when paint dries, essentially all
of its solvent content evaporates, or is driven off by heating,
but this does not occur for non-HAP chemical strippers.
According to the commenter, in the case of non-HAP chemical
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strippers, only a very small amount evaporates (<1 percent), even
over extended periods of time (>24 hrs), and that small amount is
principally water. The commenter, therefore, recommended that
any future control of VOC emissions be based on composite vapor
pressure control rather than VOC content. The commenter
suggested that this type of action would be consistent with many
local regulations, such as SCAQMD's Rule 1124.
Response: The EPA has adopted a provision which allows the
use of HAP-containing chemical strippers with abatement, to which
methylene chloride-containing strippers belong. The depainting
standard is written in a way which allows facilities to choose
from a full range of compliance options. Facilities can freely
select any technique or method that suits their business
environment and operation as long as the technique selected meets
the requirements of the standard.
The VOC content of non-HAP chemical strippers is being
addressed by the EPA in the Aerospace CTG.
Comment; Commenter IV-D-5 claimed that media blasting has
had only limited use in the industry since the manufacturers of
aircraft allow for only one media blasting in the life of an
aircraft before the aircraft's structural integrity is destroyed.
The commenter pointed out that chemical depainting has been used
for more than 50 years without damage to aircraft. The commenter
stated that aircraft in the private sector receive three to four
depainting processes during the life of the aircraft, which is in
excess of 30 years. The commenter also stated that chemical
stripping has little or no adverse effect on the aircraft. The
commenter was concerned that the standard gives the impression
that both chemical and media blasting are common methods of
aircraft depainting.
Response: The docket contains information that indicates
that both non-HAP chemical strippers and media blasting are the
depainting methods of choice by some facilities. Additionally,
the information contained in the docket indicates that
manufacturers will allow up to five plastic media blasting
depainting applications per aircraft. The standard does not
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require that particular techniques and methods of depainting be
used by a facility. The standard specifies control efficiencies
for organic HAPs and workplace standards to control the inorganic
HAP emissions from non-HAP dry media blasting operations.
Comment: Commenter IV-D-45 stated that they, like other
support companies, have little flexibility in the compounds used
for depainting since these are specified by their customers and
ultimately by the aircraft OEMs.
The commenter requested a more gradual implementation of the
depainting requirements by reducing the quantity of HAP contained
in depainting compounds incrementally over the first 5 years of
the NESHAP enactment before zero HAP depainting compounds are
required. The commenter believes that a incremental
implementation schedule would allow sufficient time for suitable
depainting alternatives to be completely demonstrated and tested.
Response: As discussed in a previous response, the EPA has
adopted depainting provisions which allow many techniques and
methods to be used. Acceptable methods of depainting would
include: media blasting with emissions controls, mechanical
sanding, non-HAP chemical strippers, and HAP-containing chemical
strippers with abatement. All of these methods are currently
used in production environments. In addition, facilities that
choose to use HAP-containing strippers can use carbon adsorbers
to control emissions or any other type of control device approved
by the permitting agency. The menu of options available in the
final rule should provide affected facilities with a great deal
of flexibility to choose the method which best fits into their
business climate. Since each of the options listed above has
been demonstrated conclusively, no extensions of the compliance
date will be granted.
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8.0 CHEMICAL MILLING MASKANT APPLICATION
8.1 GENERAL COMMENTS
Comment: Commenter IV-D-15 asked if all other maskants,
line sealers, and repair materials will be controlled at the
local level.
Response: The EPA cannot speculate as to what local
districts and agencies may do. The EPA has included bonding
maskants, critical use and line sealer maskants, and maskants
used with Type I etchants in the list of specialty coatings;
therefore, these coating categories will be addressed in the CTG.
However, the EPA has recently requested additional information
from the industry on the usage of each of these maskants and
their application. If the EPA determines that there are
sufficient reasons to reconsider coverage of these coating
categories in the NESHAP, then the EPA will issue a supplemental
proposal to solicit public comment on the information collected
by the Agency.
Comment: Commenter IV-D-15 stated that the proposed
regulation as it pertains to chemical milling maskants is
realistic and attainable. The commenter stated that there are
now approximately 20-22 facilities applying chemical milling
maskants in the United States, with numerous companies having
closed during the last 2 years due to the cost of complying with
the current environmental rules. The commenter believes half of
those currently in business may already meet the proposed
regulations. The commenter also estimated that those now in
compliance account for 75 percent of the maskant applied.
The commenter stated that electrostatic and HVLP spray
equipment do not work for chemical milling maskants due to the
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composition and solids content and that the proposed rule was
appropriate for not requiring them for chemical milling maskants.
According to the commenter, hot or cold airless spray equipment
is used successfully throughout the world.
Response: The EPA did not specify any application method
for chemical milling maskants for the reasons cited by the
commenter. Maskants are required to comply by meeting specific
VOC/HAP content or by controlling the emissions to obtain an 81
percent overall control system efficiency.
8.2 EXEMPTION REQUEST
Comment: Commenter IV-D-06 stated that the emissions from
the use of touch-up maskants are insignificant when compared to
the overall emissions from the coating operation and recommended
that touch-up maskants be exempted from the rule. The commenter
stated that the EPA used the same rationale to exempt touch-up
operations associated with topcoats and primers. Further, the
commenter stated that it is impractical to move a part back into
the control device to effect a minor repair for a company using a
control device to comply with the standard. To do so creates an
additional processing step with little environmental benefit.
Therefore, as long as a company is able to achieve the emission
reduction required by the MACT floor, the commenter believes the
rule should exempt maskant touch-up.
Response: The EPA has accepted the commenter's
recommendation and has added §63.747(c)(3) which states:
"(c)(3) The requirements of paragraphs (c)(1) and (c)(2) of
this section do not apply to the following:
(i) Touch-up of scratched surfaces or damaged maskant; and
(ii) Touch-up of trimmed edges."
Comment: Commenter IV-D-6 pointed out that the proposed
rule has no provision for non-compliant small volume maskant use.
According to the commenter, emissions from the use of these
maskants are negligible when compared to a facility's overall
emissions. The commenter referred to the San Diego APCD
aerospace rule and the South Coast AQMD rule, which allow 20
gallons per year per separate formulation, with 50 and 200
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gallons per year caps, respectively. Therefore, the commenter
recommended that a small-use exemption for non-compliant maskant
use be included in the NESHAP.
Response: The EPA has adopted a low-usage exemption as the
commenter suggested. The EPA will exempt from coverage any
source that uses no more than 50 gallons per year per separate
formulation, with a total annual usage cap of 200 gallons per
facility. This revision is addressed in §63.741(g) and applies
to topcoats and primers as well as chemical milling maskants.
8.3 UNCONTROLLED MASKANTS
Comment: Commenter IV-D-35 recommended that §63.747(e)(2)
be revised to read as follows:
"Use any combination of chemical milling maskants such that
the annual volume-weighted average organic HAP and VOC
content of the maskant complies with the specified content
levels."
The commenter claimed that due to the low-usage level
involved, it is reasonable to require an annual average. The
commenter believes that a daily average will impose an
unreasonable and burdensome recordkeeping requirement that will
limit the ability to average, and will not consider variations in
workload.
Commenter IV-D-29 stated that the application of maskants is
generally a batch process. According to the commenter, days may
go by without feeding the tank with fresh maskant, even though
masking operations are continuing. The commenter believes that
this makes daily recordkeeping of usage inaccurate and
impractical.
Commenter IV-D-29 believes that the averaging periods for
maskants in §63.749(g) should be 30 days at a minimum. According
to the commenter, small volumes of maskants will be used in any
24-hour period and, with a 24-hour averaging period, the
magnitude of measurement error propagation will be greater than
or equal to the magnitude of the measurement. The commenter
claimed that 24-hour volume weighted averages would be
meaningless. The commenter requested that 90-day performance
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periods be considered as a reasonable period for verification of
compliant maskant organic HAP and VOC solvent content less water.
In addition, the coiranenter suggested that the EPA record annual
records for compliant material recordkeeping.
The commenter recommended the following revisions:
"§63.752(f)(1)...
(i) The mass of organic HAP emitted per unit volume of
chemical milling maskant as applied (less water)(HJ and the
mass of VOC emitted per unit volume of chemical milling
maskant formulation used each month annually.
(iii) The volume (gallons) of each chemical milling maskant
formulation used each month annually.
(2) For chemical milling maskants complying with the
organic HAP or VOC content by averaging:
(i) The mass of organic HAP emitted monthly volume-weighted
average masses of organic HAP emitted per unit volume ..."
Response: Facilities may choose to use compliant maskants
that do not require control devices or daily averaging. In order
to provide facilities with additional flexibility, the EPA has
changed the averaging period from 1 day to 30 days, unless the
permitting agency specifies a shorter averaging period as part of
an ambient ozone control program.
8.4 LEVEL OF OVERALL EMISSIONS CONTROL
Comment: Two commenters (IV-D-6, IV-D-42) recommended that
the 81 percent emission reduction requirement for chemical
milling maskants be adopted as an overall control efficiency for
all maskant usage. Commenter IV-D-6 stated that if a facility is
able to reduce its emissions from a maskant application operation
by reducing their HAP and VOC emissions by at least 81 percent,
it should not matter that some small volume non-compliant
maskants are not controlled.
The commenter suggested that a standard requiring a higher
control efficiency, but allowing the minor use of non-compliant
maskants outright or by averaging with controlled maskants, would
be equivalent to the proposed rule while still allowing industry
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the operational flexibility to function efficiently. The
commenter, therefore, recommended raising the control efficiency
to 85 percent and allowing either a small-use exemption or the
averaging of controlled with uncontrolled maskants. The
commenter believes that the EPA can allow the small volume use of
non-compliant coatings, and still achieve the defined MACT floor.
Commenter IV-D-42 believes that prohibiting an add-on
emission control system from capturing only a portion of the
emissions from nonexempt maskant application operations may lead
to unnecessary costs in capturing and controlling small amounts
of HAP or VOC in low concentration emission streams. The
commenter, therefore, recommended that the overall emission
reduction requirement remain at 81 percent, but that an add-on
emission control system be allowed to capture only a portion of
the total emissions.
Commenter IV-D-31 stated that, if the Agency determines that
substitution is only possible for maskants used with Type II
etchants, the EPA must require use of an appropriate control
device providing for 81 percent reduction in HAP and VOC
emissions, taking into account capture and destruction
efficiencies.
Response: The standard has been clarified to state that
"each control system shall reduce the operation's organic HAP and
VOC emissions to the atmosphere by 81 percent." In addition,
definitions have been included for both "control device" and
"control system" to distinguish the equipment that destroys or
recovers the pollutants from the total capture and control
system. The standard specifies that add-on emission control
systems must be used to capture emissions resulting from non-
compliant maskant usage when facilities are not using averaging
to achieve compliance.
8.5 MASKANT USAGE WITH TYPE I AND TYPE II ETCHANTS
Comment: Three commenters (IV-D-18, IV-D-19, IV-D-31)
recommended the elimination of the exemption for chemical milling
maskant operations involving Type I etchant. The commenters were
perplexed as to why Type I etchants should be considered
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differently from Type II etchants, since VOC's are not contained
in the etchants. Two commenters (IV-D-18, IV-D-19) noted that
there is no relationship between the emissions of VOC from the
maskant and its toxicity and the media the maskant is used in.
Commenter IV-D-75 stated that waterborne chemical milling
maskant for use with Type I etchants is being implemented at
McDonnell Douglas, Long Beach, is in use at McClellan Air Force
Base in Sacramento, and is approved for use at Hill Air Force
Base in Utah. The commenter also stated that many facilities
operate chemical milling processes by utilizing both Type I and
Type II etchants for different types of applications. According
to the commenter, the following facilities using Type I etchants
have installed control devices: Grumman in New York, Aerochem in
Los Angeles, McDonnell Douglas in Long Beach and Chem-Tronics in
San Diego.
Commenter IV-D-75 stated that a low-VOC, waterborne maskant
used with Type I and Type II etchants has passed tests for the
following process applications: anodizing in chromic,
phosphoric, and sulfuric solutions. The commenter stated that
the waterborne maskant is also used for chemical milling of
titanium aerospace component parts and for nickel plating of
engine blades, and in the stretch forming process.
Commenter IV-D-31 stated that the EPA must require the
maximum achievable reductions from all maskants, not just those
used with Type II etchants.
Four commenters (IV-D-29, IV-D-35, IV-D-82, IV-D-89)
recommended that the low-VOC content maskant be required only
when used exclusively with Type II etchants.
Three commenters (IV-D-80, IV-D-82, IV-D-83) stated that the
technology which may have caused the EPA to reconsider control
for maskants use in Type I etchants is too new to rely on and
doesn't represent a MACT floor. Commenter IV-D-83 does not
believe that a limit of 1.3 Ib/gal represents MACT for chemical
milling maskants used with Type I etchants.
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Commenter IV-D-82 provided a position paper and test results
to support their point of view that maskants used with Type I
etchants should be exempt from the standard.
Three commenters (IV-D-80, IV-D-82, IV-D-89) stated that the
low-VOC (1.3 Ib/gal) maskant has not been used successfully on
high strength, high copper content aluminum alloys which make up
a majority of Type I processed parts.
Commenter IV-D-89 provided several technical analyses to
support their view that Type I etchants provide required
specialized material properties on milled metals. The commenter
also provided details on Type I and Type II etchant composition
and processing temperature.
Commenter IV-D-89 surveyed nine aerospace manufacturers to
gather information on the HAP content of maskants used for Type I
chemical milling operations. The commenter stated that the
results indicated that maskants are available that perform
acceptably in Type II etchants and meet the proposed NESHAP
standard (160 grams of HAP per liter or less). The commenter
also stated that the survey indicated that no manufacturer has
successfully used low organic HAP content maskants (less than
about 1,000 grams of HAP per liter) for Type I chemical milling
of production parts. The commenter concluded that, at the
present time, no maskant with a HAP content of less than about
1,000 grams per liter has been demonstrated to work in practice
for Type I chemical milling of aluminum alloys.
Commenter IV-D-89 stated that Type II etchants are used in
about 85 percent of the aluminum chemical milling applications.
Due to the cost of emissions control and technical concerns, the
commenter recommended that maskants used in Type I etchants
remain exempt from the NESHAP. In addition, the commenter stated
that the HAP emissions for Type I chemical milling operations are
estimated to be less than 1 percent of the total HAP emissions
from the aerospace industry. The commenter also recommended that
the exemption of Type I chemical milling maskant operations from
the organic HAP content requirements be reexamined in 2 years
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since active research on low-HAP maskants for Type I chemical
milling shows some promise.
Two commenters (IV-D-80, IV-D-82) believe that the EPA
should classify maskants used in Type I etchants as a specialty
coating regulated under the CTG. Commenter IV-D-80 stated that
these maskants represent a very small percentage of maskant
usage. Commenter IV-D-82 stated that Type I maskant materials
should be regulated in the aerospace CTG in order to preserve the
technology investment in pollution prevention.
Commenter IV-D-80 was also concerned that specialty coating
maskants may inadvertently be required to meet the standards set
for Type II chemical milling solutions. The commenter stated
that line seal and seal coat maskants are used in extremely low
volumes, and that there are no low organic HAP/VOC alternatives.
The industry asked the EPA to clarify that the chemical milling
maskant application requirements do not apply to specialty
coating maskants (bonding, critical use and line sealer, seal
coat, and Type I maskants) applied to parts that may later be
processed in a Type II chemical milling solution.
Two commenters (IV-D-29, IV-D-35) recommended that
§63.747(a) be revised to read as follows:
"Applicability. This section applies to chemical milling
maskant application operations in which only Type II
chemical milling etchants are used."
Response: The EPA has collected information which indicates
that maskants used with Type I etchants have specialized
properties and that the usage of these maskants is small when
compared to maskants used with Type II etchants. Based on the
information available, the EPA will not regulate maskants used
with Type I etchants under the NESHAP, but will address them in
the Aerospace CTG. However, the EPA has recently requested
additional information from the industry on the usage of maskants
with Type I etchants. If the EPA determines that there are
sufficient reasons to reconsider coverage of this coating
category in the NESHAP, then the EPA will issue a supplemental
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proposal to solicit public comment on the information collected
by the Agency.
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9.0 HANDLING AND STORAGE OF WASTE
9.1 NEED FOR STANDARD
Comment: Four commenters (IV-D-27, IV-D-29, IV-30, IV-D-40)
believe there are compelling reasons for the EPA to reconsider
its proposed requirements for waste handling and storage
(§63.748). Commenter IV-D-27 believes that the EPA has proposed
housekeeping measures for HAP-containing non-RCRA wastes without
offering any justification. Two commenters (IV-D-29, IV-D-40)
believe that the waste handling and storage requirements are
overly broad and burdensome. Two commenters (IV-D-30, IV-D-40)
stated that many of the waste streams resulting from aerospace
operations are already regulated under RCRA. Commenter IV-D-40
believes that additional requirements for the remaining wastes
would over-regulate wastes with little or no potential for HAP
emissions, resulting in no environmental benefits and imposing
significant operational and economic impacts on the industry.
Three commenters (IV-D-27, IV-D-29, IV-D-40) pointed out
that the proposed rule does not account for the emission
potential of certain HAP-containing waste. The commenters stated
that aerospace parts such as wings or fins that have been coated
with a paint containing an organic HAP may become waste if
damaged. The commenters stated that because the cured paint
contains a HAP (even though it has no potential to emit the HAP),
the proposed rule would require a special container to enclose
this waste, and the same scenario would apply to paint chips or
spent blast media. Commenter IV-D-40 believes that it was not
the intent of the EPA to impose such disruptive impacts on the
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manufacturing process while obtaining no reductions in HAP emissions
Commenter IV-D-40 noted that the RCRA exceptions are debris,
rags contaminated with oils, and automotive filters, all of which
are regulated by the State. These wastes and other non-aerospace
process related waste streams, such as facility operation and
maintenance wastes, are applicable broadly to any industry,
contain trace amounts of HAP, and would be over-regulated by the
proposed regulation. Two commenters (IV-D-29, IV-D-40) provided
two examples where trace amounts of HAP occur: oil-water
separators in storm and industrial sewers and the steam cleaning
of vehicles. They noted that in both of these cases, the
proposed regulation would require that the materials be kept in
closed containers. Commenter IV-D-40 stated that since the
thousands of other oil-water separators that may contain organic
HAP's will not be regulated, simple equity demands modification
of the rule to restrict its applicability.
Additionally, commenter IV-D-29 stated that under the RCRA
regulatory system, once wastewaters have entered an NPDES
treatment or pretreatment facility, they are excluded from
hazardous waste regulation, assuming they would otherwise be
included. This commenter noted that although the preamble to the
Aerospace NESHAP expressly excludes wastewater from regulation,
it does not define this term. According to this commenter, it is
not clear whether this exclusion extends to wastewater inside an
NPDES treatment system. The commenter claimed that if the EPA
were to apply the same conceptual distinction to non-hazardous
wastewaters that it applies to hazardous wastewaters, vast
quantities of such wastewaters could be regulated as "wastes"
under the Aerospace NESHAP.
The same commenter stated that the EPA's concern for the
evaporation of the volatile portion of the organic HAP contained
in the waste does not limit the scope by volatility to organic
HAP. Commenter IV-D-27 stated that the emissions from HAP-
containing non-RCRA wastes will already be controlled by
limitations on vapor pressure and HAP/VOC content. Two
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commenters (IV-D-29, IV-D-35) recommended that the following text
be added to the end of §63.741(e):
"Wastes which have a. composite vapor pressure of less than
45 mm Hg (24.1 in. H2O) or less at 20 C (68 F) are excluded
from this rule."
Commenter IV-D-29 claimed that this change would clarify the
EPA's stated intention of limiting the applicability to volatile
organic HAP. Commenter IV-D-35 believes that the only wastes in
the industry that exceed this volatility threshold are already
regulated as RCRA waste. Commenter IV-D-29 also stated that no
purpose would be served by requiring vapor pressure testing of
dried paint, or metal filings, or wastewater, or any other such
discarded material that clearly cannot exceed the vapor pressure
limits.
Commenter IV-D-29 also believes that affected sources should
be able to rely (at their own risk) on general knowledge of the
process to determine whether or not specific waste streams exceed
this level, just as they are allowed to rely on general knowledge
to make the basic judgment of RCRA applicability. The commenter
claimed that any other approach would impose major process costs
with no regulatory benefit.
Two commenters (IV-D-29, IV-D-30) recommended that a de
minimis level be set so that negligible emissions would not be
regulated. Specifically, commenter IV-D-30 recommended that the
EPA eliminate §63.748 from the proposed standard to avoid
repetitious requirements that result in negligible emission
reductions. The commenter felt that, if HAP-containing waste
must be regulated separately, a minimum detection limit, similar
to that of RCRA, should be fixed. Commenter IV-D-29 recommended
that the EPA provide the administrative structure to implement a
de minimis level.
Commenter IV-D-27 suggested that the provisions in proposed
§63.748 be deleted because no quantifiable emission reductions
have been determined to justify them. If these standards cannot
be deleted, the commenter recommended that §63.748(b) be revised
as follows:
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"(b) Store all waste that contains organic HAP in closed
containers to prevent the release of liquids and solids."
This commenter also recommended that §63.749(h) (specifying
that noncompliance with the waste handling and storage
requirements constitutes a violation) be deleted. The commenter
believes that compliance with RCRA is sufficient to control HAP
emissions from the handling and storage of wastes, and claimed
that the EPA has not demonstrated that there is a need to control
all HAP-containing wastes to the level of RCRA.
Response: The general waste handling and storage provisions
of proposed §63.748 are similar to the "housekeeping measures"
for cleaning operations in §63.744(a).
None of the comments appear to address §63.748(a), which
requires the minimization of spills during the handling and
transfer of HAP-containing waste. The EPA believes that this is
a "common-sense" provision, but nonetheless necessary to ensure
that facilities formally incorporate these practices into their
operating procedures.
Paragraph (b) of this section stated at proposal:
"Store all waste that contains organic HAP in closed
containers."
The intent of this provision was not to require enclosure of
extremely large items, such as wings, or of materials with no
potential to emit HAP's into the air. However, upon reviewing
the public comments and the data previously received from the
industry, the EPA has decided to delete §63.748(b). The items of
principal concern to the EPA, solvents and solvent-laden
materials associated with cleaning operations, will be controlled
by the provisions of §63.744(a). Facilities that must already
comply with RCRA must ensure that hazardous wastes affected by
that regulation are disposed of properly. The EPA believes that
these facilities should not have to comply with additional
regulations. Information available to the Agency indicates that
the industry is practicing limited waste control measures (see
next response).
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9.2 BASIS FOR STANDARD
Comment: Three commenters (IV-D-27, IV-D-29, IV-D-40)
claimed that the EPA has provided no justification that the
proposed regulation's universal control of waste streams is
practiced in the aerospace industry and thus represents the MACT
floor. One of the commenters noted that industry data collected
through a section 114 request were very general with minimal
information on actual procedures in practice. Specifically,
commenter IV-D-27 stated that the section 114 survey of the
industry was not sufficiently detailed to establish a MACT floor
for non-RCRA wastes. To the commenter's knowledge, no aerospace
companies are practicing the techniques of handling and storing
non-RCRA wastes as would be required by the proposed rule. The
commenter claimed that, even if the EPA is able to point out a
few non-aerospace companies that are implementing some of the
proposed requirements, the nature and magnitude of their
manufacturing is fundamentally different and makes the proposed
requirements inapplicable. Therefore, the commenters recommended
that the portion of the rule pertaining to the handling and
storage of waste be deleted from the Aerospace NESHAP.
Response: In response to these comments, the EPA reviewed
the data and information collected in the survey of the industry
conducted by the EPA during development of the proposed
standards.
The numbers of facilities reporting waste streams, by
process operation, were as follows: hand-wipe cleaning (35),
spray gun cleaning (38), primer use (39), topcoat use (39),
depainting (17), and maskant use (5). For each of these
operations, the "best control level" was determined to be
temporary storage of wastes in covered drums prior to shipment
off-site. However, the wastes subject to this control in each
case consisted of such items as rags, waste paint and maskant,
thinners, sludge, and used paint filters. These item are subject
to the RCRA requirements.
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Based on these data, the EPA agrees that facilities are not
practicing these controls on non-RCRA wastes, and so the proposed
requirement in §63.748(b) has been deleted.
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10.0 COMPLIANCE DATES AND DETERMINATIONS
10.1 COMPLIANCE PERIODS
Comment: Two commenters (IV-D-1, IV-D-46) requested that
the final rule be promulgated by November 1994. Commenter IV-D-1
requested the November date in order for this agency to have time
to implement and enforce the NESHAP standard. Commenter IV-D-46
proposed the November implementation date so that the zero HAP
emission requirement for depainting operations would become
effective as soon as possible. The commenter stated that an
accelerated implementation date is both realistic and desirable
because:
• Non-HAP chemical strippers are recognized as a MACT
• Non-HAP strippers are widely available
• Non-HAP strippers are drop-in replacements for the
currently used methylene chloride strippers
• Non-HAP strippers are proven performers both in
commercial and military use.
The commenter claimed that non-HAP strippers are currently
in widespread everyday use, stripping over 30 aircraft of all
types and sizes every month, both military and commercial. The
commenter also claimed that these products are now regarded as
"best commercial practice." The commenter believes that
immediate implementation would cause no disruption in user
production schedules, but would result in the immediate removal
of hundreds of tons of HAP from the atmosphere.
Two commenters (IV-D-11, IV-D-31) recommended a compliance
date of 90 days after the effective date of the standards for the
cleaning operation housekeeping measures. Commenter IV-D-31
believes that waiting 3 years for compliance with requirements
that can practicably be complied with long before that is
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inappropriate. The commenter recommended compliance within 1
year of promulgation for most substitutions and reformulations.
The commenter stated that because the EPA has based its standards
on already proven substitution methods, a source should be
expected to upgrade its program within a year.
Commenter IV-D-11 stated that a compliance date of 90 days
after the effective date of the standards for the use of enclosed
containers for flush cleaning solvents in §63.744(d), and the
provisions for handling and storage of waste in §63.748, is a
reasonable amount of time for sources to comply. The commenter
believes that these pollution prevention and housekeeping
measures will have minimal economic impacts and can be readily
implemented. The commenter also stated that a compliance date of
180 days after the effective date of the standards for the spray
gun cleaning provisions in §63.744(c) is a reasonable allowance
of time for sources to comply.
Commenter IV-D-31 recommended requiring implementation of
the NESHAP's emission limitations within 1 year of promulgation
of the NESHAP, or within 1 week of promulgation of SIP
limitations, whichever is later. The commenter stated that
moderate ozone nonattainment areas need emission reductions in
1994, 1995, and 1996 in order to attain by 1996. The commenter
also noted that serious nonattainment areas must have clean air
in 1997, 1998, and 1999 in order to attain the standard. Due to
transport problems, the commenter concluded, control in serious,
severe, and extreme areas in 1994-6 may be necessary to allow
moderate areas to attain. For these reasons, the commenter
claimed there is no justification for allowing CTG implementation
to wait until 3 years after State adoption of a SIP revision,
since MACT compliance begins before the SIP is adopted
implementing the CTG.
Five commenters (IV-D-11, IV-D-12, IV-D-27, IV-D-29, IV-D-
37) recommended that the EPA allow the full 3-year period for
implementation of any and all compliance measures to meet the new
Aerospace NESHAP requirements, noting that the text of the
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proposed Aerospace NESHAP would give sources the full 3 years
allowed by the Clean Air Act to comply with the final rule.
Commenter IV-D-12 believes that the probability of
compliance would be enhanced if the EPA and States provide
outreach services to affected facilities. The commenter noted
that they have begun conducting a series of workshops to provide
sources with an overview of the various proposed MACT standards.
Commenter IV-D-11 recommended that technical assistance be
afforded to all sources in the form of up-to-date data on
available technologies and methods of economical implementation,
and assistance should be provided in the form of listing product
substitutions for coatings and hand-wipe cleaning solvents, and
disseminating the results of such substitutions to industry as
information becomes available. The commenter also felt that new
sources should comply with MACT upon startup.
Commenter IV-D-37 stated that compliance with the proposed
NESHAP for airline maintenance facilities will require extensive
facility construction and modification; new equipment and product
research, budgeting, and procurement; chemical evaluation and
reformulation; maintenance procedure revisions; and maintenance
training and safety program changes. Even with respect to
certain cleaning operation housekeeping measures and spray gun
cleaning provisions-- for which 90-day and 180-day compliance
schedules, respectively, have apparently been considered by the
EPA--the airlines still will be required to identify, test,
budget for, and procure new equipment and materials, such as
closed spray gun cleaning systems and solvent containers that
meet NESHAP requirements. The commenter stated that modified
waste disposal and work practice procedures relating to solvent
usage and storage will have to be devised and implemented;
workers will need to be taught new spray gun cleaning and
handling methods; and new rules will have to be developed and
enforced to ensure workplace compliance with applicable health,
fire, and safety codes. The commenter believes that employee
behavior modifications cannot effectively be accomplished within
3- to 6-month timeframes, particularly considering the collective
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bargaining requirements many airlines must satisfy in order to
implement workplace procedural changes.
Two commenters (IV-D-27, IV-D-29) stated that the EPA is
correct in recognizing the need for the full 3-year period for
facilities to come into compliance with the multitude of new
requirements proposed in the rule, especially given the nature of
testing and qualification necessary for hand-wipe cleaning
solvents, primers, topcoats, and chemical milling maskants.
The commenters provided several reasons why the aerospace
industry will need the full 3-year period for implementation of
the many time-consuming compliance measures to meet the new
Aerospace NESHAP standards. First, many of the compliance
requirements are most effectively and efficiently met through the
reformulation of materials which, in turn, is dependent on
successful technical development by material manufacturers. The
commenters claimed that in order to meet the stringent
qualification requirements inherent to aerospace products, the
reformulated materials must undergo a reiterative process of
testing and improvement and retesting before they can meet the
necessary specifications. The commenters noted that one major
aerospace firm has tested 240 types of low-VOC coatings with 6
having been proved successful. Moreover, the average period for
full qualification (receipt of sample to full engineering and
manufacturing qualification) is 5 to 10 years. The commenters
proposed that the same concerns are experienced in qualifying new
cleaning solvents. These solvents present additional
implementation problems associated with thousands of different
application needs and because qualification testing cannot
possibly cover every use. The commenters claimed that emission
reductions gained by the new solvents could be offset by the
additional cleaning or coating operations required when the
solvent fails to work properly, not to mention the expense and
time impact on production flows.
Second, facilities may be required to undergo physical
changes as well as procure new materials. The commenters noted
that closed containers for flush cleaning may require significant
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facility changes and the spray gun standards may require new
equipment in some areas.
Third, the Aerospace NESHAP will require many changes in
procedure at facilities. The commenters claimed that sources
will have to ensure that all materials perform adequately (e.g.,
bags/containers may be permeable to new cleaning solvents). They
also noted that workers will be required to learn and follow new
procedures which will take extra time and effort over their
normal work assignments.
Fourth, it will be impossible to meet the waste handling and
storage requirements within the 90-day period after promulgation.
The commenters believe that 90 days is insufficient to obtain a
clear regulatory interpretation of what is needed, design and
construct the necessary "closed" system, and implement any
procedural changes necessary to the cleaning operation.
One of the commenters suggested that the EPA provide
assistance to help sources meet the 3-year compliance deadline.
The commenter stated that assistance could be through technical
information exchanges, research on alternative emission reduction
measures, electronic bulletin boards, meetings, and/or
publications.
Finally, both commenters pointed out that the proposal
preamble discussion correctly identifies the substantial
administrative impacts of requiring multiple compliance dates for
a single NESHAP at a single source. According to these
commenters and commenter IV-D-37, incorporating these
requirements into title V operating permits is a major concern to
both agencies and the industry. The commenters claimed that
varied compliance dates could necessitate several reopenings of a
source's operating permit {or amendments to its permit
application) as each new requirement came into effect. They
believe that imposing such an increased workload on the title V
permit program in its startup days would serve no useful purpose,
particularly since the reopening of a permit will be a lengthy
and resource intensive enterprise, taking up to 18 months per
revision.
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Commenter IV-D-38 recommended that the prohibition on HAP
strippers be implemented over a longer period of time (e.g., 5 to
7 years). The commenter believes that this action by the Agency
would allow for a more orderly transition to non-HAP
technologies.
Response: The Aerospace NESHAP standards were proposed in
the Federal Register on June 6, 1994 (59 FR 29216). A subsequent
FR notice (59 FR 60101) was published on November 22, 1994 in
order to request comment on several amendments to the original
proposal. The second comment period ended on January 6, 1995.
The Agency then considered the comments received and made
revisions to the rule. An intensive review by several offices of
the EPA and other Government entities ensued, followed by further
revisions and ultimately finalization of the rule. The final
NESHAP was promulgated in accordance with this schedule, in the
most timely manner possible.
Section 112(i)(3) of the Act requires the Administrator to
establish a compliance date for existing sources which shall
provide for compliance as expeditiously as practicable, but in no
event later than 3 years after the effective date (promulgation)
of the standards. In addition, the Administrator (or a State
with a program approved by the EPA under title V) may issue a
permit that grants up to a 1-year extension to comply with the
standards if an additional period is necessary for the
installation of controls.
The general compliance requirement of 3 years that was
included in proposed §63.749(a) is a direct reflection of this
statutory requirement. The EPA is restrained from extending the
time limit on this requirement; further, the Agency believes that
the 3-year period is reasonable for the emission control
standards and practices called for in this regulation. At the
same time, it does not appear appropriate to specify any shorter
compliance periods for specific standards. The EPA recognizes
that the industry will need to institute new programs and develop
new operational standards, purchase equipment, and educate
personnel for each of the standards within the regulation.
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Therefore, compliance periods of 90 days, 180 days, or 1 year are
not considered appropriate. States or local districts, however,
are free to specify shorter compliance periods under their own
regulations.
The EPA agrees with the comments that EPA outreach efforts,
technical assistance, and various forms of encouragement and
education should be available to sources and agencies attempting
to implement these regulatory requirements. The Agency will be
cooperating with these entities after promulgation in developing
resources to answer these needs.
Comment: Three commenters (IV-D-30, IV-D-35, IV-D-38)
stated that many of the government organizations that depend on
the Federal funding cycle may not be able to respond quickly
enough to meet the standards within 3 years.
Commenter IV-D-30 stated that the technical requirements for
materials used in space operations typically are rigorous.
According to the commenter, the requirements of specific
materials may dictate that it is not possible to identify and
qualify replacements in this time period, or at all. The
commenter believes that some consideration should be made for
compliance extensions or waivers in such cases.
Commenter IV-D-38 stated that, in light of extended military
funding cycles, it is likely that several facilities will not be
able to install MACT depainting technologies involving media
blasting in time to comply with the proposed standard. The
commenter noted that military construction cycles are planned 5
to 7 years in advance. As a result, the commenter believes that
military facilities that have not already received Congressional
authorization for depainting projects would be unlikely to be
able to comply with the MACT standard.
Commenter IV-D-35 stated that under Federal fiscal law, the
military is required to follow detailed and lengthy procedures
when obligating appropriated funds, and environmental compliance
funding is no exception. The commenter pointed out that major
construction projects typically require a minimum of a 5- to 7-
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year budget cycle once the requirements are known, and operating
funds require a 3-year budget cycle. The commenter claimed that
unless an expedited method for obligating funds is found, it will
be difficult for the military to meet the compliance schedule.
The commenter noted that the military has unique funding
constraints; unlike commercial enterprises, the military must
adhere to Federal laws when obligating appropriated funds (See 31
U.S. C 1301, 1341, 1342, 1350, and 1351). These laws place
limitations on expenditures based on purpose, amount, and when
funds can be spent. For example, there are separate expenditure
accounts for military personnel, operations and maintenance,
procurement, research and development, real property maintenance,
and MILCON. The commenter pointed out that failure to follow the
law can cause a violation of the Antideficiency Act (31 U.S.C
1301) and lead to criminal and civil liability for those
involved.
The commenter acknowledged that many aspects of the proposed
rule will require affected sources to invest in MACT technology.
The commenter stated that in cases where a construction project
costs more than $300,000, the military must use MILCON funds
appropriated in accordance with established MILCON funding
cycles. The commenter noted that projects costing less than
$300,000 are normally financed from an O&M account and approved
at the base or command level. Also, the budgetary cycle for
minor military construction projects is shorter than the 5 to 7
years for MILCON projects. However, even if funds can be
appropriated within 3 years, the commenter claimed that actual
completion of the compliance projects would take longer.
According to the commenter, the EPA's determination that it
apparently lacks the authority to defer compliance to the Clean
Air Act, compounds the problem for the military. The commenter
noted that, by court order, the EPA must no later than July 1995
issue the Aerospace NESHAP rule and that compliance shall not be
later than July 1998, assuming a July 1995 promulgation date.
The commenter stated that, barring an extension under section
112(i)(B) or an exemption under section 118(b), any anticipated
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MILCON requirements to comply with the Aerospace NESHAP must be
submitted to Congress for approval in the FY97 program (allowing
for construction lead time). The commenter suggested that the
key to the preparation of such MILCON documents is the final form
of the Aerospace rule. The commenter pointed out that since this
rule will not be issued until mid-1995, installations will not be
able to identify their requirements in time to make the FY97 or
the FY98 Congressional budget deadlines. The military budget
process takes an average of 5 years or more once a requirement is
determined, which is out of phase with the EPA's mandated NESHAP
implementation timelines.
The commenter stated that, following promulgation of the
rule, the military will do its best to quickly build a budget
request for adequate compliance funding. The commenter suggested
that the EPA could provide valuable assistance by helping the
military determine exactly what projects will meet the rule
requirements. The commenter noted that technical assistance and
coordination would save time and money in terms of selecting the
right technology for a given activity. The commenter claimed
that the EPA should be aware of the costs associated with the
standards it sets in the NESHAP. According to the commenter, as
the cost of certain activities escalates the more likely it is
that MILCON funding will be required to comply. The commenter
believes this will push back ultimate compliance due to the
delays in obtaining those funds.
The commenter claimed that a strict 3-year implementation
schedule for incorporating new control technologies places DoD in
the untenable position of having to choose between delaying
critical mission maintenance or violating the Clean Air Act. The
commenter noted that failure to comply with the NESHAP schedule
can potentially result in either shutdown of operations at
locations in need of MILCON funding or cause a violation of
section 112(i)(3) and the facility's title V operating permit.
The commenter stated that the military may have to delay
maintenance or contract with others to do it, which could
severely impact safety and military readiness. The commenter
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suggested that at a minimum, costs will increase dramatically and
disruption to operations will occur. The commenter pointed out
that the near-term MILCON requirements for the DoD are
conservatively estimated in excess of $1.2 billion if the final
regulation remains unchanged.
The commenter stated that the EPA can reduce the effect of
the MILCON funding issue by adopting their recommendations,
particularly those related to maintenance painting, mechanical
sanding, touch up and repair, flexible primer and CARC topcoat,
emission averaging, and recordkeeping and reporting. The
commenter believes that early and committed cooperation between
the EPA and the military will reduce, but not eliminate, the
potential for missed deadlines. The commenter, therefore,
recommended that the EPA make an effort to relax compliance
schedules to mirror the military budget cycle. The commenter
concluded that the DoD will need the full 3 years of
implementation time allowed and the 1-year time extension
available under section 112 (i) (3) (B).
Response: The EPA is aware of the military funding cycle
and has kept the military informed at every stage of the
regulation development. Therefore, the EPA believes that it has
given DoD a sufficient notice and time for compliance.
Comment: Commenter IV-D-ll (a State agency) believes that
the alternative compliance dates for certain pollution prevention
and housekeeping measures represent a sufficient time allowance
for sources to comply, but are not reasonable considering the
delegation procedures set out in subpart E of part 63. This
agency will have to follow procedures set forth in the State
rulemaking process in order to gain delegation. The commenter
stated that, if the EPA does set forth those deadlines for
compliance with portions of the rule, the EPA must commit to
enforcement of those portions in the interim time between
promulgation and the time delegation takes effect.
Response: [This is a policy question which will be
addressed in the final document.]
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10.2 COMPLIANCE EXTENSIONS
Comment: Commenter IV-D-14 suggested a case-by-case
extension determination for sources encountering difficulties
with the 3-year compliance deadline. The commenter believes that
technical assistance and training should be provided on the basic
provisions and requirements of this NESHAP for the affected
sources. The commenter suggested distributing information on new
and established products and equipment that meet the provisions
of the NESHAP.
Commenter IV-D-31 stated that, in cases where no compliant
coatings are immediately available for a particular application
(which will be very rare with the current proposed emission
limitations), sources should be able to apply for an extension of
up to 3 years after the promulgation date, a procedure that
should be the exception, not the rule. The commenter claimed
that these requests should be routinely granted only when
technology-forcing substitutions going substantially beyond the
standards are being pursued. This commenter recommended that the
EPA specify that extensions will be process- and material-
specific. The commenter believes this will minimize the tendency
to seek broad across-the-board extensions and will instead limit
them to genuinely extraordinary situations.
The same commenter felt that the EPA may not allow for
compliance extensions through State inaction, and that allowing
an extension without State action on a relevant request would be
grossly unfair to the public. The allowance of a fourth year for
compliance is an extraordinary measure and ought not to be
routinely granted.
The commenter also objected to allowing sources an
additional 30 days to respond to a denial of a compliance
extension. Thus, they felt that the final rule should not
require mandatory reconsideration of supplemental information.
However, if the final rule contains this provision, the public
should be given a right to consideration of the supplementary
information submitted after a requested extension is granted.
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Response: [This is a policy question which will be
addressed in the final document.]
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11.0 TEST METHODS AND PROCEDURES
11.1 USE OF MANUFACTURER'S DATA
Comment: Commenter IV-D-35 pointed out that the proposed
NESHAP requires compliance determinations based upon sampling and
testing, instead of reliance upon data supplied by manufacturers
and suppliers, and places the burden of proof of vapor pressure,
VOC content, and HAP content compliance on the affected facility
by forcing them to perform their own analysis.
Seven commenters (IV-D-27, IV-D-29, IV-D-30, IV-D-31, IV-D-
32, IV-D-35, IV-D-43) stated that the EPA should specify that
manufacturers of coatings and solvents are required to supply
information for the VOC and HAP content and the vapor pressure.
Commenter IV-D-31 stated that the manufacturers of these products
are legitimately considered part of the aerospace industry for
the purposes of the regulation and, therefore, the EPA may
legitimately regulate them to this extent under this rule.
Commenter IV-D-35 pointed out that California districts have
imposed labeling requirements on manufacturers in order to obtain
this information. Commenter IV-D-31 recommended that
manufacturers be held liable if a material does not meet the
content specifications as stated by the manufacturer. Commenter
IV-D-43 stated that the manufacturers should list the test method
used to determine the content or vapor pressure on the Material
Safety Data Sheet (MSDS).
Commenter IV-D-27 advanced the following arguments in favor
of manufacturer labeling: (1) the VOC content, HAP content, and
solvent vapor pressures are most reliably determined when
calculated by the manufacturer, based on the formula for the
product; (2) the test methods recommended by the EPA were not
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developed for low-VOC or water-based coatings, and the result is
non-reproducible data when tested at the lower limits of the
method; and (3) testing by the end user is expensive and time-
consuming .
Commenter IV-D-31 recommended periodic testing of the
coatings to verify the composition and accurate labeling. The
commenter stated that the EPA can either require this of the
coating manufacturer or of the aerospace companies. According to
the commenter, if this is not done the rule will lack any
specific obligation to insure that compliance actually occurs.
Three commenters (IV-D-27, IV-D-30, IV-D-35) noted that
obtaining formulation data from the MSDS is very difficult. Four
commenters (IV-D-10, IV-D-27, IV-D-30, IV-D-35) noted that the
precise amounts of components are rarely given on the MSDS.
Specifically, two commenters (IV-D-35, IV-D-27) stated that, at
best, users have a MSDS which lists selected chemicals and a
concentration range. Commenter IV-D-35 pointed out that the user
will know all components only if they independently perform
analyses of each product (a time-consuming and costly process) or
the EPA mandates that manufacturers provide said information.
This commenter (p. 1-5-2) also stated that MSDSs are readily
available sources of information on commercially available
materials (single or multiple component) and should be used to
determine compliance. The commenter claimed that since
manufacturer's data are acceptable for determining compliance
with §63.744(b)(1) and Table 3 of §63.744(b), it should be
acceptable to determine compliance for all hand-wipe solvents.
The commenter also suggested that MSDSs be used to determine the
HAP and VOC content of strippers and aerospace coatings.
Four commenters (IV-D-29, IV-D-35, IV-D-30, IV-D-27) stated
that requiring manufacturers to fully label their products would
relieve the burden faced by individual facilities by eliminating
redundant and expensive testing. Commenter IV-D-27 added that
small users, such as subcontractors to larger aerospace
manufacturers, do not have laboratories to conduct VOC and HAP
content or solvent vapor pressure tests.
11-2
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Two commenters (IV-D-29, IV-D-32) supported the EPA's
proposal to allow facilities to obtain organic HAP content from
manufacturer's data, and recommended that this provision be
extended and clarified. Specifically, the commenters opposed
wording that would require owners and operators who cannot
determine organic HAP content from the manufacturer's data to
"submit an alternative procedure for determining the organic HAP
content for approval by the Administrator" (§63.750). The
commenters stated that users of these products must be able to
rely on manufacturers' data with a degree of certainty and should
not be required to provide data themselves. Commenter IV-D-29
recommended that proposed §63.746(b)(1) be amended to require no
organic HAP emissions "based on manufacturers' data."
According to this commenter, even if valid and practical
test methods existed to determine the VOC and HAP content of
these materials at the user level, it would still be unreasonable
to focus compliance determinations on users rather than
manufacturers. The commenter claimed that as the proposed
regulation was written, users will be at enforcement risk from
the results of an invalid test method. The commenter believes
that in many cases, the chemical constituents of these materials
cannot be reverse engineered by a user's chemists.
Three commenters (IV-D-10, IV-D-29, IV-D-35) suggested that
end users do not have knowledge of all components in the cleaning
solvent because manufacturers typically classify such information
as proprietary.
Commenter IV-D-30 stated that companies could negotiate a
proprietary agreement with the vendor to obtain the (potentially)
proprietary formulation from which HAP content could be
calculated. For a large operation, this could result in a
company having to safeguard a large amount of proprietary
information for various vendor companies. The commenter believes
this is an unreasonable burden, and therefore recommended that
manufacturers be required to label their products.
Commenter IV-D-30 stated for many multi-component cleaners,
particularly those which the vendor considers proprietary, it may
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be impossible or economically infeasible to determine the vapor
pressure for each lot of material. In such cases, the commenter
stated that the aerospace organization may have to rely on the
material manufacturer for vapor pressure information. The
commenter believes that it is unreasonable to hold the aerospace
organization accountable for a material characteristic that the
user has no control over or has no way of confirming
independently.
Two commenters (IV-D-30, IV-D-35) suggested that the EPA
consider other compliance options, including for example,
developing a qualification procedure that could be used
voluntarily by manufacturers and suppliers to certify their
solvents and coatings. Commenter IV-D-35 believes the
qualification procedure would allow the aerospace industry and
the user community to reference the EPA voluntary product
certification procedures as a part of their material procurement
specifications.
Commenter IV-D-10 requested that the EPA allow a verbal
composition claim by the manufacturer regarding ingredient
breakdown percentages. The commenter sought clarification on
whether verbally supplied vendor information can be utilized by a
facility for compliance determinations.
Two commenters (IV-D-27, IV-D-29) noted that in order to
determine compliance with the various standards, the EPA proposed
to rely on both source testing conducted by the individual
companies subject to the rule and data provided by manufacturers.
The commenters believe that many of the test methods proposed for
determining compliance with the emission limitations contained in
the Aerospace NESHAP are either technically invalid, cannot
practicably be applied at the user level, or are simply
undefined. The commenters claimed that the problem is compounded
by the EPA's failure to consistently define a rule for the use of
manufacturer's data or to specify the weight such data will be
given in compliance determinations.
Commenter IV-D-29 pointed out that in the special case of
hand-wipe solvents, additional considerations demonstrate even
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more conclusively the need to place the responsibility on the
manufacturer. The commenter stated that many of the
manufacturers and formulators of these blends determine the vapor
pressures of the individual components from their suppliers or
from engineering references and use the mole fractions and
Raoult's Law to determine the overall vapor pressure of the
solvent blend. According to the commenter, the manufacturers do
not attempt direct measurement of vapor pressure of the overall
solvent blend because of the problems associated with multi-
component blends. The commenter believes that because the
manufacturer already has this information on the components, the
manufacturer should be responsible for certifying the composite
vapor pressure of the blend to the user and/or regulatory agency.
The commenter pointed out that this information is already
required under the OSHA Hazard Communication Standard. (29 CFR
§1900.1200.) Further, MSDS's are required to contain, as part of
the hazard determination, the "[p]hysical and chemical
characteristics of the hazardous chemical (such as vapor
pressure, flashpoint).11 (29 CFR §1910 .1200 (g) (2) (ii) ) . The
commenter also noted that manufacturers are required to "ensure
that the information recorded accurately reflects that scientific
evidence used in making the hazard determination." (Id.
§1910.1200(g)(5)).
Commenter IV-D-27 recommended that the following definition
for "compliant material" be added to the proposed rule:
"Compliant material means a material certified by the
coating manufacturer to be compliant with the applicable VOC
and/or HAP content requirements of this regulation."
Commenter IV-D-35 recommended that proposed §63.750(a) be
revised to read as follows:
"Composition determination. Compliance with the hand-wipe
cleaning solvent approved composition list specified in
§63.744(b) for hand-wipe cleaning solvents shall be
determined from manufacturer's data provided from the MSDS
for single component or commercially available multiple
component cleaning solvents. The data must identify all
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non-proprietary components of the cleaning solvent in
percentages normally identified by an MSDS and demonstrate
that one of the approved composition definitions is met."
In another part of their comments, the same commenter
suggested a different revision for §63.750(a) as follows:
"Composition determination. Compliance with the hand-wipe
cleaning solvent approved composition list specified in
§63.744(b)(1) for hand-wipe cleaning solvents shall be
demonstrated using data supplied by the manufacturer of the
cleaning solvent. The—data must—identify—all—components—o~f
trie cleaning £Oiv6n.u &nci cic:rtiGnst2rd.L.& tnau oneox t rife
ffl.ppirGvscicompos 11 ion del mi t iori£>ism& t. Data considered
acceptable include: identification of all components of the
cleaning solvent: manufacturer's letter certifying the
product complies with the composition list; or
manufacturer's product data sheet stating the product
complies with the composition list."
The commenter also recommended that proposed §63.750(b) be
revised to read as follows to allow use of manufacturer's data
for commercial blends and in determining the composition of
solvents blended in-house:
11 (b) Vapor Pressure Determination. The composite vapor
pressure of cleaning solvents used in a cleaning operation
subject to this subpart shall be determined as follows (for
water dilutable hand-wipe solvents, the concentrated or as-
received vapor pressure shall be used):
(1) For single component and for commercially available
multiple component hand-wipe cleaning solvents, the vapor
pressure shall be determined by using the MSDS or other
manufacturer's supplied data.
(2) The composite vapor pressure of a hand-wipe solvent
blended in-house (diluting hand-wipe solvent with water is
excluded) by a cleaning operation subject to this part or
chemicals for which manufacturer's data is not available,
shall be determined by the owner or operator submitting an
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alternative procedure for determining the vapor pressure to
the administrator for approval."
This commenter also recommended that proposed
§63.750(e)(3)(i) be revised to read as follows in order to
require that compliance be determined by using manufacturers'
data or MSDS during enforcement and inspections:
"Compliance in calculating Gx during enforcement inspections
shall be based upon the VOC content obtained using
manufacturer's data or the MSDS."
The commenter also recommended the deletion of
§63.750(e) (3) (ii), and the revision of §63.750(j) to read as
follows:
"(j) Organic HAP content of chemical strippers. The
organic HAP content of chemical strippers used in depainting
operations subject to §63.746(b)(1) shall be determined from
manufacturer's formulation data. If the organic HAP content
cannot be determined from the manufacturer's data, or the
MSDS, then the owner or operator shall submit an alternative
procedure for determining the organic HAP content for
approval by the Administrator or use a stripper for which
HAP content can be determined."
Commenter IV-F-1 manufactures a HAP-free terpene solvent
blend for cleaning applications, which has a vapor pressure of
1-2 mm Hg and a VOC content of 850 g/liter. The commenter stated
that since VOC emissions are often not calculated correctly, it
is very important to look at vapor pressure as well as VOC
content. The commenter requested that they not be asked to
disclose the composition of the solvent blends due to the amount
of R & D that has gone into them.
Response: Under the NESHAP standard setting process, the
EPA establishes requirements for practices that will reduce HAP
emissions from a specific source category. These requirements
will have little or no environmental effect if they are not
enforceable. In order to ensure that these aerospace
requirements can be enforced by the appropriate control agencies,
11-7
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they are designed to apply to owners and operators of the major
source facilities where affected operations are being conducted.
Clearly, most of the liquid cleaners used in the aerospace
industry are developed and manufactured by commercial enterprises
that specialize in these products. These firms will be aware of
the new requirements and will need in many cases to reformulate
their products in accord with the standards. Solvent
manufacturers that cannot produce effective, compliant solvent
blends and also certify to customers the makeup of these blends
will find it impossible to compete in this "new market."
Similarly, aerospace companies are unlikely to patronize
suppliers that do not provide reliable assurances that their
products satisfy the necessary restrictions on constituents and
physical properties.
The EPA believes that affected facilities should only have
to perform this testing in order to verify a manufacturer's
analysis of a new product or at its discretion to periodically
verify that the nominal analysis for an existing product is being
maintained. The Agency does not foresee this as an excessive
burden on the industry.
11.2 VAPOR PRESSURE
Comment: Two commenters (IV-D-29, IV-D-30) stated that
regarding the calculation of the composite vapor pressure of a
material, it appears that the rule applies to all ingredients
including water, exempt compounds, and non-HAP. The commenters
believe this requirement is unnecessarily restrictive and pointed
out that a non-HAP, exempt, single component solvent, such as an
HFC, could not be used for non-exempt cleaning operations if its
vapor pressure exceeds 45 mm Hg. Commenter IV-D-29 felt that
including water and exempt compounds is contrary to the intent cf
the regulation and of section 112 of the Act. Commenter IV-D-35
stated that diluting a cleaning solvent with water should be
exempt from vapor pressure requirements, as water poses no
environmental hazard.
Commenter IV-D-35 stated that if a facility mixes a multiple
component solvent in-house, they should be allowed to calculate
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the vapor pressure from the components of the mixture without use
of a gas chromatography or other approved ASTM test.
The commenter stated that standard engineering reference texts
may be used to determine the vapor pressure of a single component
solvent but that users of blended hand-wipe solvents may not use
manufacturer's data or reference texts to show that the wipe
solvent meets the vapor pressure requirements of the proposed
rule.
Commenter IV-D-29 felt that the test method for vapor
pressure determination, gas chromatography per ASTM E 260-85, is
not an appropriate method for many materials that would comply
with the proposed regulation. The commenter felt that if a user
(or a regulating agency) could calculate a wide range of vapor
pressures using standard engineering sources, it is clear that
great confusion (and potential legal battles) will occur when
trying to define whether a solvent blend meets the 45 mm Hg
limit. The commenter stated that manufacturers often consider
the constituents of their materials to be proprietary
information, making vapor pressure calculations difficult. The
commenter believes that manufacturers would be more likely to
provide the vapor pressure of the blended solvent.
Commenter IV-D-29 stated that the cost of equipment and
necessary testing to ensure compliance with the vapor pressure
standard would be high. The commenter suggested that the initial
equipment costs for an automated gas chromatography system would
be approximately $30,000, and claimed that many small component
suppliers and subcontractors do not have the equipment or the
trained personnel to perform such analyses. According to the
commenter, the present cost for running a single sample per ASTM
E 260 at an outside laboratory is approximately $175 or more,
depending on the complexity of the blend. The commenter proposed
that if each aerospace facility (the EPA has estimated that there
are 2,800) has only one blended solvent and runs only one sample
annually at $175, the annual cost is $490,000. The commenter
believes that the regulation as written would require thousands
11-9
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of aerospace facilities to perform redundant testing of these
materials, multiplying these costs greatly.
Finally, the commenter understood that the use of an
isoteniscope to determine vapor pressure was recommended by one
manufacturer. The commenter stated that this method is highly
complex and extremely costly to facilitate, as evidenced by the
very few laboratories in the U.S. capable of performing this
test. The commenter pointed out that ASTM has not established
the precision for this test because of the lack of participating
laboratories.
The commenter recommended the following revision to address
the issues raised above on compliant materials:
"§63.750 Test methods and procedures.
(b) Vapor pressure determination. The composite vapor
pressure of hand-wipe cleaning solvents used in a cleaning
operation subject to this subpart shall be determined as
follows using data supplied by the manufacturer:"
The commenter recommended the deletion of §63.750(b)(1) and
(b) (2) .
Response: With regard to the use of gas chromatography, the
EPA believes it is an appropriate method and necessary in order
to verify the actual organic composition of blended solvent
mixtures. As pointed out in the comments, the exact composition
of cleaners is often not divulged by manufacturers. Also, there
can be numerous values in standard references for vapor pressure
data due to various test methods used, etc. The EPA has
concluded that GC analysis is the only verifiable means of
determining compliance with the vapor pressure limits for
approved manufactured cleaning solvents. For solvent blends
mixed in-house, the EPA agrees that GC analysis should not be
necessary if the facility is aware of all the constituents that
have gone into the mixture. Therefore, the final rule allows a
facility to use manufacturers' data or standard reference texts
to calculate the composite vapor pressure.
The composite vapor pressure limit for hand-wipe solvents is
intended to apply to the entire solvent blend. However, the EPA
11-10
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does not intend to require solvents that contain no HAP or VOC to
be regulated by the standard. Therefore, in order to clarify the
applicability of the standard, §63.744(b) has been revised by
adding the following provision:
"Cleaning solvent solutions that contain no HAP or VOC are
exempt from the requirements in paragraphs (b)(1), (b)(2),
and (b)(3)."
This revision relieves facilities of the requirement to conduct
testing on solvents that contain no HAP or VOC. In addition, the
EPA has added the composite vapor pressure calculation to the
final rule (§63.750(b) (2)) . The calculation exempts water, non-
HAP, and non-VOC compounds from the vapor pressure determination.
The EPA agrees that vapor pressure testing using an
isoteniscope has not been fully established at this time (and may
have accuracy limitations), and the Agency is not prescribing
this method.
Comment: Commenter IV-D-30 recommended the use of the vapor
pressure calculation currently being used by SCAQMD and proposed
for use in the Ventura APCD. The commenter enclosed a copy of
SCAQMD1s Rule 1171 for consideration.
Commenter IV-D-29 stated that the specified test method
parameters and conditions (gas chromatography system, column
packing and length, sample size, temperature, detector, etc.)
leave many factors to be defined by the chemist/analyst
performing the test. The commenter believes that it is likely
that manufacturers, users, and regulators will obtain somewhat
different results because each analyst defines these factors
differently. The commenter also claimed that the method is
inaccurate for complex blends containing materials such as
naphtha or mineral spirits, as well as for blends containing
water that do not meet the definition of an aqueous cleaner
(which would remove them from the testing requirements). The
commenter also noted that attempting to analyze blends containing
detergents and surfactants, common constituents which act to
enhance performance, may ruin the column and will cause excessive
downtime of the gas chromatography system. The commenter pointed
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out that GC analysis requires comparison of the sample with high-
purity standards of each of the constituents. The commenter
stated that unless a complete list of all constituents is
available to the tester, it is extremely difficult to identify
the constituents so that these standards can be obtained.
Without these standards, it is impossible to quantify the
individual components and, thus, the individual mole fractions
required for the overall vapor pressure calculation. The
commenter also noted that lack of standards increases the
likelihood of misidentification and/or incorrect quantification
of components. Further, composite vapor pressure can be
incorrectly calculated since standard engineering texts list
varying vapor pressures for a single component.
Commenter IV-D-43 noted that proposed §63.750(b)(2) required
vapor pressure to be determined by ASTM E 260-85. The commenter
stated that ASTM E 260-85 is a standard practice for packed
column gas chromatography (GC) and it serves as a general guide
to the application of GC with packed columns and as a reference
for the writing and reporting of GC methods. The commenter
pointed out that ASTM E 260-85 is not, however, a test method and
it does not specify the procedures or conditions to be followed
to conduct an analysis. The commenter believes that this could
lead to the use of various methods that specify a variety of
conditions and procedures that will result in values that are not
identical. The commenter, therefore, recommended that a method
similar to AQMD Method 304-91 be specified to quantify the amount
of each organic compound in the blend.
Response: The EPA has not experienced the problem of
detergents causing the difficulty in GC equipment described by
commenter IV-D-29. Detergents and surfactants are not expected
to volatilize and reach the analytical column.
It is not possible to write one detailed method to cover all
of the compounds that may be present, and so the regulation cites
the most current version of the general GC method (written as
ASTM E 260-**).
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In addition, the EPA has adopted the calculation for
composite vapor pressure listed in SCAQMD's Rule 1171. This
calculation has been added to §63.750{b)(2).
Comment: Commenter IV-D-46 stated that if vapor pressure
control is instituted for non-HAP chemical strippers, it should
be based on a calculated value. The commenter claimed that there
is no theoretically sound, accurate method of determining the
vapor pressure of complex mixtures. The commenter pointed out
that the usual method, using an isoteniscope, is reliable only
for pure liquids. Furthermore, the commenter stated that to
obtain reliable results, it is indispensable that all dissolved
gases from the atmosphere be removed, which can only be done by
repeated boiling of the liquid under vacuum. The commenter noted
that this process unavoidably changes the composition of a
mixture by depleting it of the more volatile components, which
gives an unavoidable error to the result, biasing it toward the
low side. The commenter, therefore, recommended that Raoult's
Law be used for vapor pressure determination. The commenter
noted that this would be consistent with SCAQMD's Rule 1124.
Response: The depainting provisions of §63.746 do not
specify a vapor pressure limit for non-HAP chemical stripper
depainting operations. However, the commenter!s statements do
apply to the requirements for hand-wipe cleaning solvents.
§63.740(b)(2) does require the vapor pressure determination for a
solvent blend to be made by the use of Raoult's Law.
Comment: Commenter IV-D-34, along with two other companies,
has determined that non-ideal gases and complex dissimilar
species of materials, such as those formed in azeotropes, do not
conform consistently with Raoult's Law. The commenter stated
that ASTM D 2879-92 seems to be a more reliable method for
solvents with vapor pressures to 1 mm Hg. The commenter
submitted their two solvents to a lab utilizing ASTM D 2879-92.
The commenter stated that the test was relatively inexpensive and
was performed in a timely manner. The test results indicated
that the solvents meet the requirements in the NESHAP. The
commenter pointed out that the vapor pressure for one solvent was
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1.54 using Raoult's Law and 1.1 when the ASTM test was used. The
cornmenter stated that although the difference between calculated
and tested results in this case is small, if a blend were on the
borderline, the ASTM method would probably give an accurate and
definitive true vapor pressure.
Response: ASTM D 2879-92 is a standard test method for
vapor pressure determination using an isoteniscope. As discussed
earlier, the EPA is not specifying this method at this time
because its precision and the relationship of its results to
other methods is not fully understood. In addition, this method
requires the removal of all dissolved gases through boiling under
vacuum, which depletes volatile components and biases the results
low. Therefore, use of Raoult's Law to calculate the vapor
pressure of mixtures is currently the best method available for
this determination.
11.3 VOC/HAP CONTENT DETERMINATION
11.3.1 Topcoats and Primers
Comment: Five commenters (IV-D-2, IV-D-23, IV-D-27, IV-D-
29, IV-D-35) stated that they strongly support the use of
manufacturer's data in determining VOC content.
Two commenters (IV-D-23, IV-D-2) were concerned that
technical difficulties associated with EPA Method 24 in
accurately analyzing the VOC content of water-based systems have
the potential for making enforcement difficult because of
overestimates of the VOC content of coatings and maskants. The
commenters, therefore, recommended that the rule allow users of
water-based coatings and maskants to rely on a certification by
the manufacturer that the material will meet the requirements of
the regulation if mixed in accordance with the manufacturer's
specifications. The commenters stated that to make this approach
enforceable, each facility must be required to keep copies of
each certification and document that all regulated coating and
maskants are mixed per specification.
Three commenters (IV-D-27, IV-D-29, IV-D-39) believe that
manufacturers' data are in general more accurate than Method 24,
particularly with respect to low solids or waterborne coatings,
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and are more consistently replicable. However, the cornmenters
noted, making Method 24 ultimately determinative effectively
undercuts flexibility. In effect, commenter IV-D-39 suggested
that it makes use of manufacturer's data "at your own risk."
Commenter IV-D-29 stated that users would essentially be forced
into a Method 24 testing program in self-defense. Commenter IV-
D-27 recommended that the manufacturer label and certify that
coatings are compliant. Commenter IV-D-39 recommended amending
the language of the proposed rule so that:
"... if there is found to be a difference in the VOC content
as determined from the manufacturer's data and that
determined using Method 24, the regulating entity will
obtain the manufacturer's data and determine whether the "as
supplied" VOC number was appropriately calculated by the
manufacturer (or if any diluent was added subsequently,
whether the "as applied" number was appropriately calculated
by the source.) If the manufacturer or the source can
satisfactorily demonstrate that the VQC content is
appropriately reflected by manufacturer's data, then the
regulating entity shall determine that no violation exists."
The commenter also noted that since the VOC limit and the
MACT limit for HAP are proposed to be identical, the use of
either formulation data or Method 24 would be appropriate for
determination of HAP. (According to the commenter, if the HAP
and VOC levels are identical, then determining VOC should allow a
manufacturer to determine the volatile HAPs present in the
formulation, since volatile HAPs would always be equal to or less
than VOC.) The commenter stated that adding preamble language
such as the following might address this issue (with appropriate
language in the actual rule as well):
"Test methods and procedures have been identified for
compliance with the organic HAP and VOC content levels.
Method 24 in appendix A to 40 CFR part 60 would be used to
determine the VOC content of each primer and topcoat as
applied. Alternatively, manufacturer's data may be used to
determine the VOC content of these coatings as supplied.
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However, in the event of any inconsistency between
manufacturer's data and Method 24 test results, the Method
24 test results will take precedence. At this time, there
is no approved test method or procedure for determining the
organic HAP content of coatings, manufacturers of coatings
may utilize appropriate methodology,, such as formulation
datar or laboratory analysis, to establish the organic HAP
content of coatings, as supplied. Alternativelyf since the
proposed VOC BACM limits are identical to the organic HAP
limits contained in thys proposalf a coatings manufacturer
may determine the VOC content of the coating as a surrogate
for volatile organic HAps, recognizing that the organic HAP
portion of the coating willf in many cases, be lower than
the number which will be established for VOC content by used
Method 24. The facility may rely on the coating
manufacturer's data to determine the organic HAP content
level of each coating. The total organic HAP weight
fraction and density of each coating as received would be
determined using the manufacturer's data. The volume of
each primer and topcoat used would be determined using user
company records. If diluent solvents or other ingredients
are added to a primer or topcoat prior to application, then
the total organic HAP and VOC weight fractions, density, and
volume must be adjusted appropriately to account for such
additions, utilizing EPA form ###, or other appropriate
method. These values would be required for each 24-hour
period; however, only changes in formulation would require
redetermination of total organic HAP and VOC weight
fractions and density."
Commenter IV-D-29 recommended the following revisions to
address the issues raised above on compliant materials:
"§63.750(e)(1) Determine the VOC content water weight
fraction (if applicable). and density of each formulation as
applied (less water and exempt solvents) using Method 24 or
manufacturer's data."
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"§63.750(f) (1) (iii) Determine the VOC content of each
primer and topcoat formulation as applied (less water and
exempt solvents) using Method 24 or from manufacturer's
data."
The commenter recommended that §63.750 (e) (3) (i) and (ii) be
deleted. The commenter also recommended that §63.750(f) (5) (i),
(ii), and (iii) be deleted, as well as §63.750(o)(2)(i) and (ii).
Additionally, the commenter recommended the deletion of
§63.750(p)(4)(i), (ii), and (iii). (These provisions give
preference to Method 24 results in enforcement inspections.)
Response: The EPA believes that use of Method 24 provides
consistent, reliable results when determining the VOC content of
primers and topcoats. The Agency must have a method that it can
utilize for enforcement purposes and a method that can be used by
all sources. Therefore, the rule provisions referring to Method
24 results taking precedence in enforcement actions have been
retained in the final rule.
Comment: Commenter IV-D-43 stated that in proposed
§63.750(e)(2), equation No. 7, the volume of exempted solvent in
1 gallon of coating (VX1) should be subtracted from the
denominator. Thus, the denominator should read (l-VWi-VXI) .
Response: The EPA agrees with the commenter, and has made
the suggested change.
Comment: Commenter IV-D-27 recommended the following
revision to proposed §63.750(d) (1) (ii) (B):
"(d)(1)(ii)(B) If a change in formulation takes place or a
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burden while formulation changes outside this range would require
a redetermination.
Response: The EPA has considered whether the allowable
change in formulation before a HAP content redetermination is
necessary should be quantified, and believes that specifying a
quantitative range would be impractical. It is unclear whether
the 10 percent figure would be applied only to the amount of
diluent solvent or to some other quantity. The Agency considers
the proposed wording (despite the unquantified term "minimal") to
constitute a better control on the coating composition than the
wording suggested by the commenter.
Comment: Commenter IV-D-12 referred to proposed
§63.745(d)(2) which specifies that compliance with the proposed
HAP and VOC content levels can be accomplished using any
combination of primers or topcoats such that the daily volume-
weighted average content of the combination complies with the
specified levels. The commenter pointed out that they have a
similar provision in their State rule (7.27-16.7 (c) (3): when one
or more of the uncontrolled coating formulations used exceeds the
VOC content limit, the daily weighted average VOC content of all
the coatings used is calculated, and the average must be below
the applicable VOC content level).
Commenter IV-D-50 suggested that the averaging method to
comply with the HAP/VOC limitations be based on a greater time
period than 1 day. The commenter supported the concept of
averaging within coating categories to achieve the proposed
coating limitations. The commenter stated that much of their
business involves repairing one entire aircraft's worth of ship
set and, as a result, for days and sometimes weeks they may use
the same customer-specified coating system. According to the
commenter, if the coating specified for a set of parts exceeds
the proposed limits based upon the proposed 1-day average method,
they must refuse the work or install controls.
The commenter suggested that if the averaging was based upon
a longer period of time (for example, on a monthly or preferably
an annual basis), they could take advantage of the fact that
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other customer-specifled coating systems used in that month or
year period would be below the proposed limits. As currently
proposed, the commenter believes that the averaging methods
provide practically no flexibility as far as their operations are
concerned.
Commenter IV-D-27 recommended the following revisions to
proposed §63.750(d):
"(d) Organic HAP content level determination - averaged
primers and topcoats. For those uncontrolled primers and
topcoats that are averaged together within their respective
coating category in order to comply with the primer and
topcoat organic HAP content levels specified in §63.745(b),
the following procedure shall be used to determine the daily
volume-weighted average mass of organic HAP emitted per
volume of coating (less water) as applied. The volume-
weighted average can be determined monthly if less than 10
gallons of primer and topcoat are used per day."
Response: In the proposed rule, the EPA specified an
averaging period of 1 day because longer-term usage of the higher
VOC coatings (such as described by commenter IV-D-50) has the
potential to create exceedances of the ozone national ambient air
quality standards (NAAQS), which are expressed in terms of daily
averages. In order to provide facilities with additional
flexibility, the EPA has changed the averaging period to monthly
or as determined by the permitting authority. The EPA believes
that this change will potentially benefit facilities located in
attainment areas. In addition, this revision will also allow
permitting authorities to retain the 1-day averaging period if it
is necessary in order to protect the NAAQS.
Comment: Commenter IV-D-30 noted that the proposed rule
would require the operator to submit an alternate procedure for
determining HAP content for approval by the EPA if the organic
HAP content of a primer, topcoat, or stripper were unavailable
from the manufacturer's formulation data. The commenter believes
this could result, depending on the method proposed, in widely
varying analytical data. According to the commenter, this
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imposes an unreasonable burden on the user, particularly small
companies or organizations. The commenter recommended that the
EPA specify a method for determining organic HAP content.
Response: The EPA included the provision that requires a
facility to submit an alternative procedure for approval because
all manufacturers may not supply the needed information. The EPA
will carefully consider any method or documentation submitted for
approval. However, the EPA does not anticipate that any such
methods or documentation will be received from the industry.
Companies that choose to not provide the needed information to
their customers will probably be forced out of business by market
conditions, especially when the customers must determine
parameters that are easily determined by the manufacturer.
11.3.2 Chemical Strippers
Comment: Commenter IV-F-1 stated that Method 24 gives an
accurate measure of the volatile content, accounts for the
presence of water, and is also recognized as not being applicable
to multi-component catalyzed type paints. As far as non-HAP
strippers are concerned, the commenter stated that their products
contain ingredients that are designed to minimize the evaporation
of the solvent during the use of the product. The commenter
suggested that if the evaporation of the solvent is forced, as in
Method 24, you get a misleading result. The commenter presented
data at the public hearing to support their view. According to
the commenter, using Method 24 negates the effect of the
evaporation control they've built into their products and grossly
overstates the solvent emissions.
Response: The EPA has not proposed Method 24 for
determination of organic HAP content in chemical strippers. The
following procedure was specified in §63.750(j):
" (j) Organic HAP content of chemical strippers. The
organic HAP content of chemical strippers used in depainting
operations subject to §63.746(b)(1) shall be determined from
manufacturer's formulation data. If the organic HAP content
cannot be determined from the manufacturer's data, then the
owner or operator shall submit an alternative procedure for
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determining the organic HAP content for approval by the
Administrator."
Comment: Commenter IV-D-35 recommended that §63.750(k)(3)
be revised to read as follows:
"C = annual average quantity (gallons per aircraft) of
organic HAP-containing chemical stripper used for spot
stripping and decal removal."
The commenter pointed out that the existing definition
states the units for "C" in gallons per aircraft for the annual
average weight, and the commenter noted that gallons are not a
unit of weight.
Response: The definition for the variable "C" has been
revised to read:
"C = annual average volume (gallons per aircraft) ..."
11.3.3 Method 24
Comment: Commenter IV-D-29 noted that the EPA has proposed
to rely on Method 24 for conclusive determinations of the VOC
content in primers, topcoats, and maskants. However, the
commenter claimed that they have stated to the EPA on numerous
occasions that Method 24 will not reliably perform this function.
ASTM Manual 4 (VOC Manual) contains a discussion of the precision
of one of the ASTM's on which Method 24 is based. According to
the commenter, the manual specifically states:
"For water-reducible coatings, as the solvent content
approaches very low values (water content approaches the
total volatile content), the indicated precision for VOC
(total volatiles minus water content) becomes totally
unreliable: calculated negative VOC values are even
possible."
The commenter stated that a presentation containing
statistically valid data using Method 24 on waterborne maskant
was made to the EPA at the October 5-6, 1993 meeting. According
to the commenter, the data presented indicated that Method 24
produces widely varying values for VOC (including negative
numbers in some cases). The commenter also stated that recent
data presented at the August 15, 1994 public hearing, indicate
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similar problems with water-reducible primers. The commenter
claimed that the primer results indicated poor repeatability
within a single laboratory with qualified personnel, as well as
poor reproducibility between labs.
In addition, the commenter stated that Method 24 was
developed for paints and related coatings and that the precision
and bias numbers as published in the associated ASTM's do not
appear to be appropriate for materials like chemical milling
maskants.
The commenter claimed that the initial cost of equipment for
Method 24 analysis would range from $40,000 to $55,000, depending
on whether the water content determination is completed using
both gas chromatography and Karl Fischer titration. The
commenter believes that it takes a trained and knowledgeable
person an entire 8-hour day to complete four samples with
duplicate runs. According to the commenter, if the pot life of
the material is short, two or more trained analysts would be
required. According to the commenter, since compliance depends
on this method (as the Aerospace NESHAP is currently drafted),
regardless of manufacturer's data, users are likely to continue
attempting to get consistent results to establish confidence in
the material. The commenter believes that repeated testing in an
attempt to force consistent results from an inappropriate test
method is expensive and not effective in reducing VOC. The
commenter pointed out that each time these materials are tested,
the test results become one more set of records that must be
retained.
The commenter stated that smaller component suppliers lack
the personnel, expertise, and equipment to perform these
analyses, which cost from $340 to $500 per sample at independent
labs. The commenter claimed that the testing would be done on
small procurement volumes, which would add (1) relatively large
costs per gallon, (2) unnecessary delays prior to being able to
use a time/temperature sensitive material, and (3) the associated
schedule and inventory cost impacts.
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The commenter stated that, if each of the estimated 2,800
aerospace facilities had only one primer, topcoat, or maskant,
and only ran one sample annually at $340 to $500, the annual cost
to industry would be between $952,000 and $1,400,00. The
commenter pointed out that the cost would have to be multiplied
many times if redundant testing to establish confidence was
necessary or if facilities had more than one primer, topcoat, or
maskant, plus the probable intent of the Aerospace NESHAP that
such testing be done on each batch of material received. Thus,
according to the commenter, the use of Method 24 will lead to
serious problems in accurately determining VOC content, will
provide no useable information, and will lead to vigorously
contested enforcement actions because of its unreliability. The
commenter believes that the more the industry shifts toward
water-reducible coatings and maskants, the worse these problems
will become.
Commenter IV-D-27 claimed that Method 24 is known to produce
errors in a VOC determination of waterborne maskants and primers.
The commenter noted that it is stated in the Method 24 sampling
manual that Method 24 has produced widely varying values for VOC
and, in some cases, negative numbers. The commenter also stated
that they have not been successful in locating the EPA certified
Method 24 labs. The commenter believes that reliance on Method
24 should be deleted.
Response: The regulatory agencies need a standard means to
check the composition of maskants and other coatings, as applied.
Method 24 is the best currently available compliance method for
determining VOC in low-VOC solvent content (high water content or
waterborne) coatings. The inherent imprecision of indirectly
determining the VOC content of such coatings by this methodology
necessitates an adjustment of the analytical results. Such
adjustments must be based on confidence limits calculated from
the precision statement established for Method 24's constituent
ASTM methods. The precision adjustment is incorporated in Method
24.
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The EPA does not currently certify laboratories; therefore,
there are no labs "certified" by the EPA to perform Method 24.
Comment; Commenter IV-D-43 stated that the proposed rule
would require the organic HAP level determination to be derived
from manufacturer's data, but according to the commenter most
manufacturer's material safety sheets do not indicate how the
density of the material is determined. The commenter, therefore,
recommended that the most recent version of ASTM D-1475 be used
to determine the density of the material.
Response: The proposed and the final rule list HAP limits
to two significant figures. The EPA believes that this level of
precision can easily be determined by several methods and
therefore will allow manufacturers to use the method of their
choice. Information collected by the EPA indicates that
manufacturers have the capability to report the density to a
higher degree of precision than two significant figures.
11.4 METHOD 309 - CARBON ADSORPTION CONTROL EFFICIENCY
Comment; Two commenters (IV-D-8, IV-D-26) requested an
extension for the comment period on proposed Method 309, with a
separate Federal Register notice specifically for the method.
Commenter IV-D-8 believes that Method 309 has the potential
to affect a number of other industries besides the aerospace
manufacturing sector; hence, a separate Federal Register notice
specifically for Method 309 should be published with an
appropriate comment period for others who undoubtedly have missed
this information due to the category it was published under.
Commenter IV-D-26 stated that proposal of Method 309 through
the aerospace NESHAP proposed rule is inappropriate due to its
inclusion in a regulation almost totally unrelated to the great
majority of carbon adsorber system users. As a result, the
commenter claimed that these users have been disadvantaged in
reviewing and commenting on the proposed method.
Commenter IV-D-33 stated that section 5.0 of Method 309
provides an empirical equation that is apparently the result of a
multi-variate step-wise regression on a large body of data on
carbon adsorber performance. The commenter pointed out that no
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information is provided to establish how the equation was
developed. According to the commenter, if the equation is
applied to a type of carbon adsorber not addressed during the
empirical equation development, it could give incorrect results.
The commenter, therefore, requested an opportunity to review the
data utilized to develop the section 5.0 empirical equation and
make further comments as appropriate.
The commenter also stated that Method 309 is extremely
complicated and would benefit from clarification of the
procedures. The commenter recommended adding a flowchart and a
summary sheet for all variables and units.
Commenter IV-D-75 believes that the appropriate length of
the rolling material balance should be short enough to closely
approximate the continuous compliance (i.e. emission rate) that
the low VOC option provides. According to the commenter, if the
timeframe is allowed to be for a long period of time, periods of
non-compliance would be difficult to detect since they would be
"averaged" across many days or weeks.
Commenter IV-D-9 expressed concern that the requirement for
complex mass balance calculations to determine the overall
control efficiency of carbon adsorption specified in §63.750(g)
may discourage the use of a technology which already has been
applied successfully at a number of aerospace manufacturing and
rework facilities. The commenter suggested that a method for the
calculation of overall control efficiency as a product of capture
and control device efficiencies similar to that described in
§63.750(h) should be sufficient to show compliance with the
standards. The commenter believes that the latter approach would
ease the burden on owners/operators of facilities choosing carbon
adsorption to comply with the standards, and thus would be less
prejudicial to the use of adsorption.
Commenter IV-D-80 stated that based upon their discussions
with companies that currently use carbon adsorbers, suppliers of
such equipment, and EPA Region VI personnel, there are many
carbon adsorber systems that are unsuited to tracking based on a
short, periodic basis or calculation based on quantity of solvent
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recovered as Method 309 requires. The commenter claimed that the
method was developed as a generic method for carbon adsorber-
type, single phase, on-site recovery systems and cannot be
expected to adequately address all possible configurations that
occur in industry.
The commenter stated that Method 309 is not appropriate for
a system where the capture solvent is sent to the control device
(carbon adsorber) on site but the solvent is not desorbed on
site. The commenter stated that this is the case when the loaded
carbon is incinerated and the energy is recovered, or when the
loaded carbon is sent off-site for regeneration and solvent
recovery. The commenter pointed out that these types of systems
do not readily lend themselves to a material balance calculated
on the quantity of solvent recovered. In addition, the commenter
stated that Method 309 fails to consider working and breathing
losses from solvent holding tanks.
The commenter pointed out that at one aerospace facility, a
permit efficiency of 90 percent has been met with a source test
at the time of permit issuance combined with use of continuous
monitors to measure inlet and exit hydrocarbon content of the air
flows. The commenter stated that calculations at this same site
using a material balance approach show capture efficiencies
ranging from 84.2 to 104.8 percent depending on the time period
used and the choice of solvent purchased versus solvent used.
The commenter believes that no aerospace company is
currently using a system similar to the type of system envisioned
by Method 309 or using a rolling material balance to keep track
of the efficiency of their carbon adsorber system. The commenter
stated that the methods currently used in the aerospace industry,
and most other industries, are: 1) operation and maintenance
according to the manufacturer's instructions, 2) periodic
monitoring of the effluent air stream to assure that solvent
breakthrough has not occurred, 3) maintaining solvent throughput
below a calculate threshold value, and 4} a combination of (1) to
(3) .
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The commenter believes that Method 309 does not meet the
objective of universal applicability and, for this reason, the
commenter suggested that the EPA adopt a flexible approach that
relies on the good sense of local agencies to solve local
problems.
Two commenters (IV-D-80, IV-D-83) believe that Method 309
is not appropriate for all systems using carbon adsorbers. The
commenters recommended that the operator of the carbon adsorber
be provided with the following options to calculate the overall
efficiency:
1. the mass balance calculations specified in Section
60.433(b), (c) , or (d), as appropriate, with the
rolling material balance period computed using appendix
A to part 63, Method 309, with the performance
averaging period of Section 60.433 equal to the rolling
material balance period of Method 309; and the control
efficiency equal to 100 minus the emission percentage
computed in Section 60.433 (b), (c), or (d), as
appropriate;
2. calculation based on measurement of flow and
concentration into and out of the carbon adsorber
control device combined with a preventative and
scheduled maintenance program based on the
manufacturer's recommendations and operation of the
control device in accordance with the manufacturer's
operating instructions;
3. calculation based on the carbon adsorber control device
manufacturer's statement of efficiency combined with a
preventative and scheduled maintenance program based on
the manufacturer's recommendations and operation of the
control device in accordance with the manufacturer's
operating instructions; or
4. calculation approved by the regulatory agency having
principal authority for enforcement of this part.
The commenters suggested a flexible approach that relies
more heavily on local agency involvement and oversight, and
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claimed that the proposed rolling material balance period is an
unworkable approach.
Commenter IV-D-29 stated that the developers of Method 309
intended that it be an option for determining compliance
averaging periods for carbon adsorber type recovery systems. The
commenter also claimed that Method 309 was not expected to
address all possible configurations that occur in industry.
Therefore, the commenter believes that Method 309 should be used
only as an option to determine compliance averaging periods in
lieu of an alternative approved by the operating permit
authority. The commenter pointed out that Method 309 was
developed using a mathematical model, Monte Carlo statistical
techniques, and curve fitting and that only limited testing of
the equations against actual field conditions was conducted for
functioning operations. The commenter believes that it is clear
that Method 309 is not well suited for recovery systems that are
monitored continuously or are sampled at infrequent intervals.
The commenter claimed that there is inadequate linkage
between Method 309 and the determination of control efficiencies
for carbon adsorber units. Additionally, the commenter believes
that if Method 309 is to be linked to §60.433, the rule should be
clarified.
The commenter, therefore, recommended the following
revisions to appendix A to part 63, Method 309:
"1.0 Applicability
This method determines the length of the rolling material
balance period used in the liquid-liquid material balance
test method to measure the overall performance of volatile
organic compound (VOC) emission control systems that recover
solvents. The rolling balance period obtained from this
method is source-specific, taking into account the
particular configuration and operating parameters of the
emission source (process) and its emission control system.
If experience indicated that the rolling material balance
period computed under this method does not accurately
represent the actual operation of the solvent recovery
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control device, the operator of the device may use a more
appropriate period by demonstration to the regulatory
authority the suitableness of the proposed alternative
period. The demonstration shall be baaed, on actual
operation of the device and supported by appropriate data
and calculations.
2.0 Summary of Method
Physical properties and usage are determined for the
solvent(s) used in the process, and configuration and
operating parameters are identified for the emission source
and its emission control system. This information is used
to calculate the concentration of VOC in the outlet air of
the capture unit, amount of VOC absorbed on the carbon,
maximum VOC loading on the carbon, unmeasured solvent
holding capacity of the solvent recovery system, and
unmeasured solvent holding capacity of the process unit.
These values are then used to calculate the rolling material
balance period.
It is the intent of the Method that the rolling material
balance period be calculated just once. However, if there
is a significant change in operations or equipment that
causes the computed period to be inappropriate, the operator
may recompute the period and the recompute period may be
applied retroactively for a period not to exceed 30
operating days."
Commenter IV-D-26 recommended that Method 309 be withdrawn
or, at a minimum, be substantially revised. The commenter
claimed that review of the method revealed a number of flaws in
the statistical treatment and inconsistencies and difficulties in
its application. The commenter suggested that the results
obtained from the method appear to have little, if any,
relationship to realistic operating conditions. According to the
commenter, if adopted, use of the method would result in the
calculation of noncompliance for numerous facilities whose air
pollution control performance greatly exceeds regulatory
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requirements. Because of these problems, the commenter believes
that the results of Method 309 would be totally meaningless.
Commenter IV-D-26 requested that the EPA provide
documentation demonstrating that the proposed method provides an
accurate representation of compliance periods for carbon
adsorbers throughout a wide range of actual operating conditions.
The commenter stated that to date, the EPA has provided no
background information regarding the basis of the method, nor has
the EPA documented that the model is consistent with actual
carbon adsorber performance data. According to the commenter,
actual operating data previously supplied to the EPA indicate
that the proposed method does not provide a realistic compliance
period.
The commenter stated that the EPA has provided no
documentation or rationale to support the development of proposed
Method 309 or to impose new, shorter-term rolling material
balance periods on facilities using carbon adsorption systems,
and that the Federal Register notice proposal for Method 309
contains no basis or justification for its proposed adoption.
Commenter IV-D-26 noted that the new source performance
standards (NSPS) for publication rotogravure, promulgated in 1982
as 40 CFR 60 subpart QQ, acknowledged the difficulty of
demonstrating compliance for carbon adsorber systems over the
short-term, and adopted instead a 30-day mass balance. The
commenter stated that there has been no fundamental change in the
design or operation of solvent recovery systems since that time,
so the need to adopt a method to establish a shorter-term rolling
average (or a rolling average at all) is questionable.
Commenter IV-D-26 stated that the use of proposed Method 309
has the potential to impose additional, more stringent control
requirements on subject facilities because the shorter compliance
period will effectively raise the level of control required of a
facility due to increasing larger statistical variations
resulting from shorter periods than the monthly standards set
forth in the NSPS for publication rotogravure.
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The commenter stated that the EPA must realize that these
short-term variations will not be fully accounted for by the
proposed method and that, as new MACT are developed, current
performance data for facilities using carbon adsorption systems
are not based on the proposed Method 309 calculations. As such,
the commenter pointed out, the baseline determination for MACT
currently being established will be invalid and will represent a
level of control higher than that which could be consistently
achieved using the compliance period calculated with proposed
Method 309.
Commenter IV-D-26 reviewed their lengthy history of
communications with the EPA concerning length of period of the
rolling material balance for compliance determinations. One item
referred to by the commenter was a document they submitted to the
EPA on March 5, 1992 that, according to the commenter, clearly
demonstrated that need for a long-term compliance period. The
commenter pointed out that the data showed that a facility
averaging 87.6 percent overall control efficiency over a 3-month
period of relatively low production would show a range of 72.0 to
98.2 percent overall control based on a 28-day rolling average,
44.6 to 130.3 percent control based on a 14-day rolling period,
and -1009.4 to 621.3 percent using a 7-day rolling average. The
commenter also noted that for a 4-month period of higher
production (average daily input of 11,370 gallons vs. 6,355
gallons), the overall recovery was 86.4 percent, with the ranges
for 28-, 14-, and 7-day rolling periods of 83.9 to 90.0 percent,
82.8 to 94.5 percent, and 79.4 to 108.8 percent, respectively.
According to the commenter, since a method for calculating a
rolling period had not yet been proposed, it was impossible to
determine what rolling period would be recommended. However, the
results of these data, according to the commenter, clearly showed
that anything short of the 30-day NSPS compliance period would
produce erroneous results, falsely indicating noncompliance for a
facility operating well above its required efficiency.
Commenter IV-D-26 stated that proposed Method 309 is unable
to accurately predict the required compliance period based on
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actual facility variables, and it appears the model was based on
steady-state operations, with no consideration given to the day-
to-day variation in operations. The commenter provided an
example which the commenter claimed indicated that the actual
annual performance of the carbon adsorption system was greater
than that required, but when the averaging rolling period was
calculated for a facility using Method 309, the calculated
efficiencies over the rolling period indicated non-compliance.
The commenter used a second example to claim that the calculated
rolling period is much shorter than necessary to consistently
show compliance with required overall control, despite the fact
the facility was operating 6 percentage points above the required
level.
The commenter provided data for 27 publication rotogravure
facilities which recorded the monthly control efficiency over a
1-year period to demonstrate the magnitude of statistical
variations. The commenter's data showed a monthly variation in
control efficiency ranging from 1.8 to 10.0 percent. The
commenter stated that, while not all of the variation could be
attributed to statistical factors alone, this magnitude of
variation is typical of that routinely encountered with a NSPS
30-day mass balance. The commenter pointed out that, if proposed
Method 309 had been used for these facilities, the annual average
would not change, but the best and worst values would be expected
to change considerably.
According to the commenter, if these same facilities were
subject to the same 84 percent requirements, but on a 3 to 5 day
period, they will in effect be required to demonstrate a higher
average level of control, probably 90 percent or greater, to
accommodate the short-term variations normally experienced.
Therefore, the commenter concluded, the EPA must consider the
impact of the proposed method on facilities now complying with
monthly demonstrations.
Commenter IV-D-26 stated that the major assumption of the
method is that the maximum solvent input into the recovery system
(with small contributions from unmeasured solvent quantities) can
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be used to define the rolling period. The commenter claimed that
this assumption is flawed for several reasons, as summarized
below.
1. The method fails to provide a consistent compliance
period for systems of different design capacity. The
commenter stated that in an ideal situation, with no
solvent in unmeasured capacity and continuous steady-
state operation, the mass balance of a carbon
adsorption system should be measurable in a consistent
and accurate manner over a short compliance period,
regardless of the system throughput, and yet the method
shows a very strong dependence of the compliance period
(NRBP) on the maximum throughput (QSP) . For this
idealized case, if all quantities of solvent can be
measured accurately and consistently, there is no
reason for NRBP to have any dependence on QSP. According
to the commenter, the fact that the model shows such a
marked dependency clearly points out that the
underlying assumptions and techniques used in
developing the proposed method are flawed, since
adsorption systems do not always operate ideally.
2. The dependence of NR3F on QSF is maintained for
situations where a percentage of the solvent is in
unmeasured capacity. For systems with equal
percentages of unmeasured solvent capacity, the
calculation of NRE:, may vary from 1 to 30 days simply
based on QSP. The commenter pointed out that simply
varying the maximum solvent use over the range of
35,000 to 45,000 gallons per day changes the rolling
period from 1 to 30 days. Again, the commenter stated
that a model that is so dependent on this single term
cannot provide an accurate assessment of the
anticipated performance.
3. The maximum daily solvent usage is not adequately
defined. Without an adequate definition, this term may
be interpreted to represent the maximum material input
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to the process units, the maximum solvent captured for
control by the carbon adsorption system, the design
capacity of the carbon adsorption system, or some other
parameter. The definition of this term will have a
very significant impact on the calculated results,
since NRBP is very dependent on it.
A further complication occurs when one considers the
actual design and operation of carbon adsorption
systems. For example, a facility with multiple
adsorbers may not fully utilize the full system
capacity if production drops below certain levels.
Where less than all of the adsorbers are being used, it
is unclear if QSP would be based on the maximum
capacity of the system or the operating capacity.
Similarly, if a significant portion of the process
equipment at a facility is shut down due to seasonal
variations in production, the maximum throughput will
be significantly less than if the whole facility is in
operation. The choice in such a situation could result
in a change in the calculated rolling average period
from 1 to 30 days.
A similar situation occurs for a facility that operates
two or more separate solvent recovery systems to
control a single process. If all of the adsorbers are
considered a single system the value of QSP for the
total facility will be significantly different than if
the systems are considered individually. Again, the
choice of QSP could result in a change in the
calculated rolling average period from 1 to 30 days,
despite the fact that the adsorbers control the same
process and the mass balance for the facility is based
on the combined recovery, rather than the individual
portions.
Day-to-day fluctuations of actual solvent input rates
may vary by an order of magnitude or more. Average or
daily input rates will obviously be below (frequently
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significantly below) the maximum input rate. Since the
calculation is based only on maximum input, these day-
to-day variations are not factored into the
calculation. Thus, for two systems with the same
design capacity, the system with lower average
throughput and the same percentage of the average in
unmeasured capacity would be subject to a shorter
rolling period. Since the method considers only QSP, VP
and VR, it cannot differentiate between a system
operating at 100 percent capacity and one operating at
a significantly lower rate. With no change in the
total quantity of unmeasured capacity or maximum
throughput, the average throughput does not affect the
calculations.
5. The calculation of C0 and, therefore, VA, is based on
the maximum daily input and either the maximum or
average air flow. The method is unclear as to the
definition of Gcu. In actuality, C0 and Gcu may vary
considerably, based on the process operation
parameters, which will affect VA and the calculation of
NRBP.
6. The method responds differently to the same throughput
numbers, depending upon the distribution of unmeasured
capacity. The commenter provided an example of the
extreme sensitivity of the calculation to the
distribution of unmeasured capacity.
The commenter stated that the EPA does not appear to have
considered the margin between the required level of control and
the actual performance of a carbon adsorption system in
developing this method and that such a failure in Method 309 is a
serious fault in the method that invalidates its usefulness.
The commenter concluded that disparity between the predicted
compliance period from proposed Method 309 and the variation in
calculated values based on actual data is due to inadequacies in
the model. The commenter pointed out that the model, based on
only three parameters, does not accurately predict the variation
11-35
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in calculated efficiencies. Otherwise, according to the
commenter, operators of carbon adsorption systems will be subject
to violations merely because of the inadequacies of the method
used to determine the compliance period.
The commenter also stated that, if the method calculates a
compliance period shorter than actual process conditions would
necessitate, a very significant potential exists that the
recovery efficiencies calculated during the prescribed rolling
average period would routinely indicate violations of control
requirements. Such perceived violations would expose a facility
to self-reporting requirements, fines and penalties, legal
expenses, and adverse publicity, even though the average
efficiency determined by a more appropriate method, such as the
30-day NSPS protocol, would show full compliance. Statistical
variation alone, according to the commenter, would result in the
lower performing facility having difficulty demonstrating
compliance over the same rolling period as the higher performing
facility. Further, this problem is aggravated as higher control
requirements are mandated.
The commenter stated that, with the extensive recordkeeping,
monitoring, and reporting requirements facilities must currently
comply with, requirements to operate pollution control devices at
all times processes are in operation, and the economic benefits a
facility receives from operating a carbon adsorption system at
maximum efficiency, routine verification of system performance
via the 30-day NSPS protocol is a more than adequate
demonstration of ongoing compliance.
The commenter provided five tables of data, examples in the
text of the letter, and seven attachments as supporting
documentation.
Commenter IV-D-26 stated that Gcu and QSP need to be clearly
defined since they play a crucial role in calculating the rolling
period. Similarly, the commenter stated that the term VP is
defined in such a way as to leave it open for interpretation,
which may significantly impact the calculation.
11-36
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Commenter IV-D-54 stated that in equation 3, calculation of
VOC adsorbed on carbon, the "Y" term, as listed, does not include
a constant "b0" . The commenter, therefore, recommended that the
following equation be used:
Y = b + (b.X
0 3
The commenter stated that the inclusion of b0 is very significant
in determining the balancing period. According to the commenter ,
when the equation on page 296 was used (without b0) , their
balancing period increased by 163 percent.
Commenter IV-D-54 noted that the description in Section
4.2.3, Unmeasured Process Holding Capacity for Solvent,
apparently conflicts with the VP definition in Section 3.0. The
commenter suggested that this may be a moot point since the upper
limit is controlled by 10 percent of QSP which is significantly
less than the solvent holding capacity can be.
This commenter pointed out that the units listed on
Worksheet A, Line 3, Solvent Liquid Density, should be Ib/gal and
not lb/lbmc:e. They also pointed out that the method does not
describe the frequency at which the calculation must be performed
or updated. The commenter stated that changes in the input
parameters can be dynamic and may change the outcome of the
equation drastically. The commenter indicated that the equation
assumes some steady state which is rare in a tape manufacturing
facility.
Commenter IV-D-55 stated that there are several inherent
problems associated with proposed Method 309. The commenter
provided the following list of items:
1. Since solvent properties in some systems will vary on a
daily basis depending on production, solvent molecular
weight and density would have to be calculated on a
daily basis to obtain accurate balances. The commenter
stated that this would increase already excessive and
complex calculations and recordkeeping requirements.
11-37
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2. Capture system air flow rates vary based on how many
(or few) emission sources are being handled at any one
time by the carbon adsorption system.
3. The maximum VOC concentration in the outlet air stream
will also vary dramatically from day-to-day depending
on production. Not only do the coatings vary in VOC
content, but the line speed at which a particular
product is run will vary. Both of these variables can
significantly affect VOC concentration in the solvent -
laden air stream.
4. There are many different types of carbons on the
market, some of which vary considerably in adsorption
capacity. Also, the virgin carbon will have a higher
adsorption capacity than reconditioned carbon. The
commenter, therefore, recommended that a standardized
test be used to measure the adsorptive capacity of the
carbon.
Finally, the commenter stated that much of Method 309
assumes a relatively static, non-changing process and does not
account for the many variables found day-to-day in the paper
coating business. The commenter believes that the steady-state
assumptions undermine some of the accuracy of the method. At a
minimum, the commenter recommended that the Agency allow
individual applicants to propose alternate methodologies for
calculating material balances in carbon adsorption systems.
Commenter IV-D-29 noted that proposed §63.750(g) references
40 CFR §60.433 for determining the overall control efficiency of
carbon adsorbers. The commenter pointed out that section 60.433
is in subpart QQ, which is the NSPS for rotogravure printing.
The commenter stated that some working changes should be made to
make the calculation methods cited in that section more generally
applicable. Specifically, the commenter believes that §60.431
and §60.433 should be revised by replacing every reference to
"ink and related coating" and "ink" with "coating material." The
commenter also pointed out that sections 60.433(b), (c), and (d)
contain the calculation method to be used when determining the
11-38
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control efficiency of carbon adsorbers. However, the commenter
stated, these latter sections contain equations for estimating
"the average VOC emission percentage" rather than "overall
control efficiency." The commenter suggested that §63.750(g) be
modified to include the conversion between these two terms.
Response: The EPA has withdrawn Method 309 until further
review and analysis of the method can be accomplished.
Comment: Commenter IV-D-55 stated that there is no perfect
method for calculating material balances for carbon adsorbers,
but there are other approaches than Method 309 that the commenter
feels present fewer variables and more practicality. The
commenter suggested an alternative method to determine the
solvent recovery efficiency that is more practical than Method
309 for facilities that operate on a 5-day week schedule, rather
than a continuous, 24-hour per day, 7-day per week cycle. The
commenter pointed out that, in a 5-day per week operation,
recovery efficiencies (1) appear to be low the first day of
startup because of solvent retention in the carbon beds, (2)
generally stabilize for the next 3 days, and (3) often exceed 100
percent the last day because of the extended steam cycle. Over
the course of a week, however, an accurate solvent efficiency can
be determined.
Using solvent recovery at a paper coating facility as an
example, the commenter stated that the input to the solvent
recovery system can be calculated easily and accurately from the
weight and volume of VOC "as applied" based on the area of the
substrate and manufacturer's data, or Method 24 or 24A test
results. The emissions would be routed to a carbon adsorption
system. The amount of solvent recovered can be easily measured
using a liquid flow meter, which would be placed in the system
after the recovered solvent/water mix (for steam purged carbon
adsorption systems) has gone through a decanter or separator tank
to separate the solvent and water mixture. The commenter
suggested that a reasonable solvent recovery efficiency could be
calculated on a daily basis by comparing the recovered volume of
solvent to the calculated volume of solvent applied at the
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coating line. The conunenter acknowledged that there are some
problems with calculating a daily efficiency in this manner. The
commenter also noted that there are problems associated with
calculating efficiency for multiple bed systems, new systems,
systems with new carbon, and systems that do not operate
continuously.
The commenter pointed out that their alternative method
calculates an overall capture and recovery efficiency. Any
fugitive losses or other losses from the point where the coating
is applied and throughout the system to the point where the
solvent recovered is included in the efficiency calculation. The
commenter believes that their method for determining a
liquid/liquid material balance would be more appropriate and
accurate for those systems not operating continuously.
Commenter IV-D-29 believes that the EPA's proposed procedure
for determining the removal efficiency of carbon adsorbers in
§63.750(g) contains a number of errors in the calculation method
and has overstated the applicability of Method 309 to some
processes.
The commenter suggested that the Aerospace NESHAP also fails
to take into account the expanding options in, and alternatives
to, carbon adsorbers. The commenter stated that not all carbon
adsorbers used by the aerospace industry involve solvent
recovery. The commenter also stated that many, if not most,
users of carbon adsorbers use the spent carbon for energy
recovery and reload the unit with fresh carbon. The commenter
believes that the proposed regulation fails to address these
situations. Therefore, the commenter recommended that control
devices that have a theoretical capability to recover captured
VOC's be given the option to determine their overall control
efficiency by direct air sampling methods (i.e., using methods in
§63.750(h)) or other alternatives approved by regulatory agencies
delegated authority to enforce part 70 or 71 air permits.
The commenter, therefore, recommended the following
revisions to part 63 in order to incorporate the comments listed
above:
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"§63.745(c)(2) Each control device shall reduce the
operation's HAP and VOC emissions to the atmosphere by 81
percent or greater, taking into account capture and
destruction efficiencies, as determined using the procedures
in §63.750(g) when a carbon adsorber or other control device
that may collect and recover volatile organic compounds is
used and in §63.750(h) when other control devices are used.
n
• * •
"§63.747(d)(2) Each control device shall reduce the
operation's HAP and VOC emissions to the atmosphere by 81
percent or greater, taking into account capture and
destruction efficiencies, as determined using the procedures
in §63.750(h) when a carbon adsorber or other control device
that may collect and recover volatile organic compounds is
used and in §63.750(h) when other control devices are used.
It
"§63.749(d)(1) Performance test periods. For compliant
coatings, each 30 day period is considered a performance
test. For compliant and noncompliant maskants that are
averaged together, each 30 day period is considered a
performance test. When using a control device three one-
hour runs or each rolling material balance period, as
allowed in S63.75Q(g), constitute the test period for the
initial and any subsequent performance test.
11
"§63.749(g)(1) Performance test periods. For compliant
maskants, each 90 day period is considered a performance
test. For compliant and noncompliant maskants that are
averaged together, each 30 day period is considered a
performance test. When using a control device, three one-
hour runs or each rolling material balance period, as
allowed in S63.750(g), constitute the test period for the
initial and any subsequent performance test.
n
• • *
"§63.750(g) Overall control efficiency - carbon adsorber.
Calculate the overall control efficiency of a carbon
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adsorber or ot;her control device that may collect and
recover volatile organic compounds used in complying with
this subpart using one of the following methods;
(1) The mass balance calculation specified in S6Q.433(b),
(c). or (d) for estimating the average VOC emission
percentage in conjunction with the following equation:
Overall Control Efficiency (%)
= 100 - average VOC emission (%)
The material averaging period shall be 30 days or the
rolling material balance period determined by Method 309:
(2) Using other methods specified in .563.750(h) :
(3) Calculations based on measurement of flow and
concentration into and out of the control device combined
with a preventapive and scheduled maintenance program based
on the manufacturer's or user's recommendations:
(4) Use of efficiency statement from control device
manufacturer combined with a preventative and scheduled
maintenance prqgram based on the manufacturer's
recommendations and operation of the control device in
accordance with the manufacturer's or user's operating
instruction: or
(5) Use any other method that receives prior approval from
the part 70 or 71 permitting authority.
ii
"§63.753(c)(1)(iv) If a carbon adsorber is used, each
performance test period when the overall control efficiency
is calculated to be less than 81 percent.
n
• * .
"§63.753(e) (1) (iii) (B) If a carbon adsorber is used, each
performance test period when the overall control efficiency
is calculated to be less than 81 percent; and
M
* • •
Response: As stated above, the EPA has withdrawn Method 309
and will continue to investigate ways to simplify the
determination of carbon adsorber efficiency. The EPA has added
extensive monitoring, compliance, and test method requirements to
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the final rule to address all of the possible carbon adsorber
control system configurations. In addition, definitions have
been added to the final rule to explain the terms contained in
the new language. The revisions incorporated in the final rule
are based on the language contained in Subpart EE--National
Emission Standards for Magnetic Tape Manufacturing Operations
that pertains to carbon adsorbers.
11.5 METHOD 18 - ALTERNATIVE CONTROL DEVICE EFFICIENCY
Comment: Commenter IV-D-29 noted that §63.750(h) of the
proposed rule specified the procedure for determining the overall
control efficiency for control devices other than carbon
adsorbers. The commenter believes that the title to this
paragraph should be changed to differentiate it from control
efficiency determinations for inorganic HAP in §63.750(1). The
commenter therefore recommended that all references in §63.750(h)
to "overall control efficiency" be changed to "overall VOC and/or
organic HAP control efficiency."
Response: The EPA agrees that the suggested change
clarifies the applicability of this rule paragraph, and has
incorporated the change into the title of the paragraph.
Comment: Commenter IV-D-29 believes a new paragraph should
be added to §63.750(h)(2) to allow use of alternative methods.
To provide this flexibility for alternative methods, the
following provision was suggested by the commenter:
"§63.750(h)(2)(v). Use any other method that receives prior
approval of the Agency, or delegated authority."
Response: As stated in §63.750(h) (2) (iii) of the proposed
rule and retained in the final rule, methods or data that have
been validated according to the applicable procedures in Method
301 are acceptable as alternatives to the required Method 18.
Since this provision allowing alternative approaches is already
in the rule, the new provision suggested by the commenter has not
been incorporated.
Comment: Commenter IV-D-29 pointed out that Method 18 does
not exclude exempted solvents when used for determining TOC. The
commenter believes that this is inconsistent with the language in
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§63.745(c) (2) and §63.747(d) (2). The commenter stated that
although control efficiencies for VOC and exempt solvents are
often nearly the same for a given control method, this will not
always be true. The commenter believes that such an exclusion
would also simplify the choice of the gas chromatographic
column(s) used and related calibrations. According to the
commenter, it is desirable that an option be added to exclude
solvents exempted from the VOC determination by adding the phrase
"or total VOCs" after reference to "TOC minus methane and ethane"
in §63.750(h)(2).
Response: The EPA agrees that a facility should have the
option of excluding exempt compounds from the VOC determination.
However, it is unlikely that any exempt compounds other than
methane and ethane would be found. Therefore, it is not
considered necessary to add the suggested phrase to
§63.750(h)(2).
Comment; Commenter IV-D-29 suggested the following changes
to make §63.750(h) more generally applicable for control devices
that remove pollutants by destruction or physical removal from
the air stream:
§63.750(h)(1): Redefine Rk as "Rk = destruction or removal
efficiency";
§63.750(h)(2)(iv) and (iv)(A): Replace "destruction
efficiency" with "destruction or removal efficiency".
§63.750(h)(2)(iv)(C) : Redefine R as "R = destruction or
removal efficiency of control device, expressed as a
percentage."
Response: The EPA agrees that the suggested revisions make
§63.750(h) more generally applicable, and has incorporated these
changes into the final rule.
Comment: Commenter IV-D-57 believes that the proposed
process for gaining approval of non-listed control techniques is
restrictive for companies of all sizes. The commenter stated
that the approval process will delay the introduction of new
approaches and new technologies, and will thereby add further
cost and diminish competitiveness. The commenter, therefore,
11-44
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recommended the adoption of a performance-based approach that
does not require a lengthy and complicated review and approval
procedure.
Respojise: The proposed rule did not restrict the type of
control devices that could be used, nor was a "list" of
acceptable equipment provided. Proposed §63.745(c) and
§63.747(c) prescribed an 81 percent reduction in organic HAP and
VOC emissions, and allowed the use of both carbon adsorption and
other types of systems. The final rule also includes a new
provision in §63.746 allowing a control device to be used in
conjunction with chemical strippers that contain HAPs. Again,
this requirement does not restrict the type of controls to be
used.
Comment: Commenter IV-D-29 noted that Method 18 must be
used when determining the destruction efficiency of these control
devices. According to the commenter, Method 18 incorporates a
contested capture efficiency test method.
The commenter noted that Method 18 references a test method
to determine capture efficiency that appears in the Chicago area
FIP (40 CFR §52.741). This capture efficiency test method
requires the construction of a temporary total enclosure ("TTE")
for capture efficiency testing if an emission source cannot meet
the requirements of a "permanent total enclosure." The commenter
claimed that this procedure is expensive, cumbersome, often
inaccurate, and may even pose a safety problem. The commenter
also claimed that the EPA's capture efficiency test method is
even disputed within the Agency. The commenter pointed out that
in late 1992, the EPA announced that it was suspending the
applicability of this test to investigate alternatives. The
commenter stated that the results of this EPA study were to have
been issued by the early part of 1994, but the revisions proposed
so far do not address the main areas of contention. Meanwhile,
to the best of the commenter's knowledge, the test is still
suspended. The commenter claimed that the method for measuring
capture efficiency in the Chicago FIP has several major problems
in its current form. The commenter believes that even this
11-45
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approach is unlikely to yield accurate results since it does not
adequately account for fugitive leaks that may not be readily
monitored (or identified). The commenter also pointed out that
it also requires the shutdown of other source operations
occurring within the building or room during a capture efficiency
test.
The commenter stated that the construction of a TTE around
an area raises some significant safety questions. The commenter
believes that the resulting changes in air flow could lead to
concentrations of VOCs that violate a PEL and/or the 25 percent
of LEL standard set by OSHA. The commenter pointed out that the
reference document "Criteria for and Verification of a Permanent
or Temporary Total Enclosure" dismisses such unsafe conditions as
the result of poor TTE design. However, the commenter believes
that a hazardous situation is still likely to occur in two
situations: (1) temporarily upon startup, while flow rates out of
the booth are adjusted prior to the collection of data, and (2)
when the TTE design parameters lead to poor mixing in the booth.
The commenter claimed that this can result in pockets of high
concentration that remain after steady state has been achieved.
The commenter stated that the accuracy of the procedure is
highly questionable. According to the commenter, it seems that
the TTE would have its own leaks and may severely alter the
ventilation normally present by creating short-circuiting air
streams from the "natural draft openings" (NDO's) to the vent.
The commenter claims that the latter effect can dramatically
change the total mass of VOC delivered to the control device
versus the vent being used to simulate the fugitive emission
amount. The commenter stated that there is a quality assurance
measurement requirement to determine VOC concentrations into the
control device with and without the TTE; however, such a quality
control condition is valid only for continuous processes.
The commenter pointed out that the reference document
requires testing to make sure concentrations delivered to the
control device do not vary by more than 10 percent as measured
with and without the TTE. The commenter stated that this is
11-46
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expensive and could potentially lead to building several TTE's
before one can pass this test. The commenter also claimed that
the method's value for batch processes is also questionable. The
commenter suggested that the EPA, in adopting the concept of TTE,
has avoided more direct approaches that will be less costly and
at least as accurate as the TTE concept.
The commenter pointed out that the current test method
requires three 8-hour sampling runs, and stated that this is
inappropriate for most intermittent, batch type operations (the
usual case for the aerospace industry). The commenter pointed
out that aerospace manufacturers often conduct several different
types of operations in the same booth. Therefore, the commenter
believes that it could take several weeks to accumulate enough
data at a given vent to constitute three consistent 8-hour
sampling runs. The commenter noted that on December 29, 1992,
the EPA proposed to change this requirement to data collection
during three production cycles, but not to be less than 3 hours
per sampling run. The commenter stated that the proposed rule
does not completely address the problem of variable batch
processes carried out at an emission point.
Finally, the commenter believes that the restriction on the
total size of NDO's to 5 percent of the total enclosure surface
area in order to qualify as a TTE or a permanent total enclosure,
as well as requirements on NDO spacing from the source of
emissions, appear to be arbitrary and may be physically
impossible to employ. Specifically, the commenter stated that
these design standards are not adequately correlated with air
stream velocities within the enclosure (e.g., the maximum NDO
area allowed should decrease and the spacing of NDO's from point
of release should increase as the release velocity of pollutants
from the point of emission within the enclosure increases).
The commenter suggested that §63.750(h)(3) be changed based
on the commenter's belief that the FIP provisions contain errors.
The following revisions to §63.750 were recommended:
"§63.750(h)(3) Determine the capture efficiency of each
control device to which organic HAP and VOC emissions from
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coating operations are vented. Capture efficiency shall be
determined by one of the following methods.
n
• * •
"S63.750(h) (3) (j.) A capture efficiency shall be assumed to
be 100 percent if the collection system for a control device
is determined to be a Permanent Total Enclosure using
Procedure T - Criteria for and Verification of a Permanent
or Temporary Total Enclosure: or
ii
"S63.750(h)(3)(ii) Capture efficiency shall be determined
using analytic procedures to determine mass of pollutants
being delivered to a control device using inlet mass rate
(E1), as calculated in paragraph (2), in conjunction with a
mass balance to determine total releases of the pollutant to
the atmosphere (Etot} . Capture efficiency js determined
using the following equation:
E
Capture efficiency = 1 - tot
E -E ,
i ap
where E? is the background concentration of the monitored
pollutant(s):
n
"S63.75Q(h)(3)(ii)(B) The length of each sampling run shall
be the duration of each production activity, but not to
exceed 8 hours.
n
...
"§63.750(h) (3) (ii) (C) E? shall be either measured at inlets
to collection device during a production run or determined
by measuring concentrations at the inlet of the control
device while the process is not operating: the latter option
applies only if it can be demonstrated that background
concentrations do not vary significantly during a sampling
run. In either case, the methods for measuring E? shall be
consistent with methods in paragraph (2).
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"S63.750 (h) (3) (ii) (D) E0 can be set at zero if the capture
efficiency of similar pollutants is based on measurements of
a. compound (s) emitted by the process that is not present in
measurable concentrations in the surrounding ambient air
when the process is not, operating.
ii
"S63.750(h)(4) Use test procedures involving building/room
enclosures or the construction of a temporary total
enclosure as specified in 52.741(a)(4)(iii): or
11
"S63.75Q(h)(5) Use any other method or data, including
direct measurement of fugitive concentrations and air flows
by a monitoring grid, that: receives prior approval of the
Agency or delegated authority."
Response: Method 18 does not reference any capture
efficiency test method. The method requiring the construction of
a TTE if a permanent total enclosure is not already in place is
designated as Method 204. Method 204 has been found in several
tests to be very precise when performed according to all of the
procedures in the method. Also, the EPA believes the method to
be safe when performed according to these procedures.
In order to ensure that concentrations entering the control
device are not unduly affected by the presence of the TTE, the
concentration with and without the TTE should not vary by more
than 10 percent. In order to accomplish this, adjustments to the
TTE can be made without the expense of constructing a new one.
The method does indeed require three 3-hour sampling runs,
and not three 8-hour runs as the commenter contends.
The EPA has reviewed the suggested regulatory language and
is not prepared to approve the commenter's approach. New capture
efficiency testing guidance is being released that allows
traditional liquid/gas (L/G) mass balances as long as the data
meet the acceptability criteria outlined in the guidance
document.
Comment: Commenter IV-D-43 stated that, to determine the
capture efficiency, the procedures in §52.741 of 40 CFR part 52
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specify the use of total enclosures. The commenter believes this
is cost-prohibitive for existing sources where total enclosures
must be constructed. The commenter, therefore, recommended
approval of low-cost alternative procedures as allowed in
§52.741(a) (4) (iii) of 40 CFR part 52. The commenter stated that
their staff has developed a suitable alternative procedure, which
is currently being reviewed by EPA/OAQPS. The commenter believes
that the timely approval of this procedure is critical to the
practical enforcement of capture efficiency provisions.
Response: The EPA's OAQPS is neither approving nor
disapproving the alternative procedure that has been submitted
for review by this control district. As mentioned in the
previous response, the EPA's latest guidance does allow
alternatives to the TTE procedures as long as data submitted for
compliance meet the criteria outlined in the guidance document.
11.6 METHOD 5 - PARTICULATE CONTROL EFFICIENCY DETERMINATION
Comment: Commenter IV-D-27 supported the use of a
manufacturer's certification of efficiency for the purpose of
compliance demonstrations for the 99 percent control efficiency
requirement for depainting operations. The commenter recommended
the following revision to §63.750(1):
"(1) Particulate filter efficiency - depainting operation.
Each owner or operator seeking to comply with the
particulate filter control efficiency specified in
§63.746(d)(2) for depainting operations that generate
airborne particulate emissions that contain inorganic HAP
shall determine the control efficiency of each particulate
filter system in accordance with Method 5 and associated
Methods 1 through 4 of part 60, Appendix A. or rely on
manufacturers efficiency specifications jn conjunction with
the pressure drop monitoring requirements per 63.745(f) (3).
Retesting shall be required whenever the type or supplier of
trhe filter media is changed, or whenever modifications are
made to the emission collection system."
Commenter IV-D-37 stated that the EPA should adopt the same
standard for depainting filters as proposed for control of
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inorganic HAP from primer and topcoat operations; i.e., a general
description of the control device combined with monitoring
requirements. However, should the Agency adopt filter
manufacturer claims as a basis for establishing a MACT standard,
the test procedures proposed in §63.750(1) should then be amended
accordingly to permit facilities to rely on filter manufacturer
efficiency representations as a method for demonstrating
conclusively that properly installed and functioning filters meet
the 99 percent control level.
Response: The proposed rule has been revised to eliminate
the requirement to use Method 5 to verify compliance with the 99
percent standard. The final rule contains workplace standards
instead of Method 5 testing (see Section 7).
Comment: According to commenter IV-D-35, Method 5 is
neither cost effective nor accurate for determining initial
compliance for particulate filter efficiency in a depainting
operation.
In addition, commenter IV-D-27 claimed that a Method 5 test
can cost from $7,000 to $9,000 and typically more for a large
aircraft hanger. The testing cost may be a minor burden for the
large aircraft manufacturing facility where only one hanger may
exist. The commenter stated that they have many small four feet
by four feet booths where depainting operations may occur. The
commenter believes that, for these small booths, the operator
should have the option of relying on the manufacturer's
efficiency data coupled with pressure drop reading requirements.
Commenter IV-D-35 stated that an additional issue for the
government is sole source procurement from filter manufacturers.
The commenter suggested it is possible that each time the filters
are replaced, testing would be required (due to a new supplier),
based on the government's legal requirements for procurement.
Finally, the commenter claimed that the cost of testing by Method
5 would be $30,000 to $40,000 for a large depainting hangar. The
commenter claimed that this cost is excessive, considering that
the test method has not been validated for this type of source.
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Commenter IV-D-27 believes that the requirement to retest
whenever the type or supplier of filter media is changed would
incur excessive cost and delays in production. The commenter
claimed that the efficiency of a given filter would not change
simply because the supplier changed, but the efficiency could
change if the type of filter was changed.
Response: As discussed in the previous response, the
requirement in proposed §63.750(1) to use Method 5 for
determining control efficiency has been deleted. In the final
rule, the standards for topcoat and primer application operations
and depainting operations contain specific workplace practices
that must be followed. These requirements are designed to ensure
that the filter system will control inorganic HAP as intended and
that the owner operates and maintains the system according to a
specific operating and maintenance plan. The EPA is
investigating approaches that would reduce the filter testing
requirements at facilities.
Comment: Commenter IV-D-20 stated that they are subject to
several air toxic regulations and initially followed regulatory
guidelines which recommend that emission inventories of air
toxics be based on engineering assumptions and conservative
emission factors in the absence of specific source test data.
This commenter did perform source testing, and claimed that the
results demonstrate a significant difference between emissions
calculated using the source test results and emissions based on
the traditional mass balance using Agency suggested methods.
According to the commenter, source testing indicated that 22
percent of paint overspray drops out of the air onto the floor.
However, in the mass balance emission calculation method,
regulatory agencies did not allow credit for dropout rates in the
absence of test data. The commenter stated that an 82 to 96
percent reduction in emissions was demonstrated upon utilization
of source test reports and emission factors.
Commenter IV-D-35 commissioned an EPA Method 5 test to study
the validity of the method and the 99 percent control efficiency
requirement for depainting operations. The study collected data
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on the particulate loading on both sides of one control device
for the particulate emissions from a PMB booth at a military
base. The study was conducted during the depainting of an A-10
aircraft on August 10-12, 1994 in a facility with filter
canisters. The PMB facility consisted of a large hangar from
which exhaust gases were removed, passed through two parallel dry
filter systems, and recirculated to the building. Triplicate
determinations of the removal efficiency of the canisters were
93, 85, and 74 percent. The commenter noted that the properties
measured at the inlet of the filter showed a linear relationship
to the rate of generation of particles, while the rate of
emissions at the outlet was essentially constant, independent of
the rate of input. The commenter concluded that linearity
indicated that a low loading to the filter produces a lower
removal efficiency. According to the commenter, since the
emissions remain relatively constant, a process which has lower
particulate emissions is penalized. The commenter provided a
summary of the data collected during three Method 5 sampling
runs, and a summary of the calculated collection efficiencies for
the dry filter system of each of the three runs.
The commenter also pointed out that there were insufficient
data to determine if a correlation exists between particulate
control efficiency and inorganic HAP control efficiency for a
depaint process.
Commenter IV-D-52 was concerned about the feasibility of
using EPA Method 5 and associated Methods l through 4 to
determine particulate control efficiency in a large enclosure or
blasting hanger. The commenter pointed out that, for some
equipment configurations, it may be difficult or impossible to
collect a meaningful upstream particulate sample to establish
control efficiency. The commenter recommended that the EPA allow
the reviewing agency to accept alternate methods, including a
design review, to demonstrate compliance with this requirement.
Two commenters (IV-D-29, IV-D-35) recommended that
§63.750(1) be deleted from the rule.
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According to commenter IV-D-29, even if particulate filter
efficiency were appropriate, the test method relied on is not.
The commenter claimed that Method 5 was designed for particulate
grain loading out of a stack or duct, and does not measure for
input into a control system. Two commenters (IV-D-29, IV-D-43)
stated that Method 5 could not be used to determine control
efficiency in a depainting hangar with a filter bank.
Specifically, commenter IV-D-29 stated that testing could not be
conducted if the hangar has a large inducted inlet. Commenter
IV-D-43 stated that inlet testing is not feasible. Commenter IV-
D-43 recommended that the EPA allow the local districts to:
1. Accept manufacturers' certified efficiency for the
filter, or
2. Limit the mass emission rate from the exhaust stack to
below a certain concentration level (grains/dscfm) or a
de minimis amount such as l pound per day.
In addition, commenter IV-D-29 stated that manufacturers'
claims are rarely substantiated by Method 5.
Response: The EPA deleted the Method 5 testing requirement
because no data were available from the industry. In addition,
the efficiencies reported on the section 114 information
collection requests were based on manufacturer's claims and not
test data. Information obtained by the EPA indicated that the
manufacturer's did not use a standard test to quantify the
claimed filter efficiencies.
As mentioned in the previous response, the EPA is currently
investigating a number of options with respect to implementing
controls on the emissions from coating and depainting operations.
Test methods are being developed which will allow filter
manufacturers to qualify their filters as EPA-approved. The
Agency would then require affected sources to use EPA-approved
filters in the control devices used to capture the particulate
emissions from spray coating operations. The EPA plans to issue
a supplemental proposal to the NESHAP that will solicit public
comments on a provision that the Agency deems to be enforceable
and guarantees the public's safety.
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11.7 TRANSFER EFFICIENCY FOR COATING OPERATIONS
Comment: Commenter IV-D-11 stated that the requirements for
the proposed alternative application method are sufficient to
ensure that an owner/operator not bias the test results, provided
that detailed recordkeeping is maintained during the initial 90-
day test period and during the alternative application method
test period. The commenter recommended that recordkeeping data
include, but not be limited to: a wet or dry film thickness for
both test periods, coating solids content data if wet film
testing is utilized, and emissions monitoring data for both test
periods. According to the commenter, these data would determine
if equivalent dried film thicknesses were applied. The commenter
pointed out that if detailed recordkeeping were not done, it
would be difficult to determine the validity of the testing
procedures and the results.
Commenter IV-D-35 provided information pertaining to
transfer efficiency test measurements. The commenter noted that
this document underscores the differences in the proposed EPA
method and that adopted by the SCAQMD and the Bay area. The
commenter pointed out that the EPA added the requirement that
"the dry film thickness for the non-approved gun must be the same
as for the approved gun and that the test be conducted over a 90-
day period for each gun." The commenter suggested that when
considering the fact that HVLP does not provide the same low film
thickness when using some paints as other non-approved guns, it
becomes important to establish the required film thickness
necessary to satisfy the performance specification associated
with the desired finish product. Therefore, the commenter
recommended that the EPA delete the requirement that both guns
meet that same dry film thickness as the HVLP. According to the
commenter, if 1 mil thickness will meet the specification using
the alternative coating gun, there is no need to require 2 mils
just because the HVLP applies the coating too thick. The
commenter suggested that the conditions of an alternative test
method can, if required, be incorporated in an operating
condition in the owner's or operator's operating permit to assure
11-55
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that the same conditions are adhered to as were used during the
test.
Commenter IV-D-35 recommended that the EPA consider adopting
a national standard to test by, i.e. ASTM, or developing one.
The commenter stated that the test must incorporate, as a part of
the standard, the amount of paint applied per surface area
coated. The commenter suggested that failure to publish a
workable and practical alternative coating test method will
prevent DoD and industry from adopting new or equivalent
technologies that could surpass the transfer efficiency of HVLP,
etc.
Commenter IV-D-ll stated that they do not routinely require
transfer efficiency testing, but usually specify what types of
application equipment are acceptable in rules or permits.
Commenter IV-D-43 stated that they, along with another
source, are co-sponsoring a project to establish a test method
protocol for transfer efficiency. The commenter believes that
the establishment of the test protocol will aid the manufacturers
of spray equipment to test and certify their equipment for sale.
The commenter also believes this will eliminate the need for
individual facilities to test and certify their spray guns to
demonstrate equivalent transfer efficiency. The commenter
recommended the following:
1. The establishment of a minimum required transfer
efficiency, 65 percent or greater.
2. Provide provisions to allow the use of other spray
equipment, if the material sprayed, such as adhesives,
has a viscosity of 200 centipoise or greater.
Commenter IV-D-52 recommended that the EPA adopt a test
method for transfer efficiency that would shift the burden of
demonstrating equivalent performance from the facility operator
to the equipment manufacturer.
Three commenters (IV-D-29, IV-D-30, IV-D-49) recommended
that the EPA revise the rule which requires that emissions levels
from the alternative application method be determined from
production conditions.
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Commenter IV-D-29 noted that if a facility uses an
application method other than electrostatic spray or HVLP
methods, the regulation requires that alternative coating
applications must achieve equivalent results to HVLP or
electrostatic methods. The commenter believes that the EPA's
rule as proposed in §63.750 (i) does not provide flexible enough
procedures to make the comparison.
Two commenters (IV-D-29, IV-D-30) suggested that testing
accuracy would be better in a laboratory setting.
Commenter IV-D-29 stated that production simulation in a
laboratory could duplicate production conditions such as
temperature, humidity, general part configuration, airflow, etc.,
providing not only an accurate portrayal of typical production
conditions, but consistent between the two types of equipment
being compared.
Commenter IV-D-49 stated that requiring comparisons with
HVLP spray equipment results is an unacceptable capital cost to
owners who wish to install a new facility utilizing new
technology. The commenter recommended that the EPA allow
emissions comparison evaluations for new technology to be
conducted on a somewhat smaller scale.
Commenter IV-D-30 added that small scale testing would avoid
the potentially high costs of implementing a production-scale
system.
Two commenters (IV-D-29, IV-D-35) believe that the 90-day
test period for alternative application methods needs to be
revised.
According to commenter IV-D-29, a 90-day test using HVLP or
electrostatic procedures, followed by a similar period using the
alternative equipment, is not appropriate in every case. The
commenter stated that some paint booths may not see the same part
more than once every year or two, and others may see the same
parts every day or every week. Thus, any universal trial period
would not provide a representative sampling of parts in all
situations.
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Commenter IV-D-35 stated that the 90-day test period is
excessive because the DoD rarely has work orders, particularly at
rework facilities, that extend beyond 90 days.
The commenter, therefore, recommended that the EPA require
the minimum amount of time necessary to prove an alternative
coating transfer efficiency. The commenter suggested that the
regulation be rewritten to require the test protocol to be
repeated 6-10 times for each gun, without specifying a time limit
or period for testing. The commenter believes that such tests
typically could be accomplished in a timeframe of 3-4 days. The
commenter also believes that a timeframe of 3-4 days would
provide enough statistical data to provide a range of values for
both guns being evaluated.
Commenter IV-D-29 recommended the following language:
"§63.750 Test methods and procedures...
(i)(1) Alternative application method - primer and
topcoats. Each owner or operator seeking to use an
alternative application method (as allowed in
§63.745 (e) (1) (vii) in complying with the standards for
primers and topcoats shall use either the procedures
specified in paragraphs (i)(2)(i) or (i)(2)(ii) of this
section to determine the organic HAP and VOC emission levels
of the alternative application technique as compared to
either HVLP or electrostatic spray application methods.
ii
"(2)(i) The total organic HAP and VOC emissions shall be
determined for an appropriate initial period not to exceed a
maximum of 90 days. During this initial period, only HVLP
or electrostatic application methods may be used. The
emissions shall be determined based on the volumes, organic
HAP contents (less water), and VOC contents (less water and
exempt solvents) of the coatings as applied. Upon
implementation of the alternative application method, use
the alternative application method on actual production
parts or assemblies for a period of time sufficient to coat
an equivalent amount of parts and assemblies with coatings
11-58
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identical to those used in the initial period. The actual
organic HAP and VOC emissions shall be calculated, for this
post - implementation period.
( ii) Test the proposed application method against either
HVLP or electrostatic in a laboratory or pilot production
area, using parts and coatings representative of the
process (es) where the alternative method is to be used. The
lab test will use the same part conf iguration (s) and the
same number of parts for both the proposed method and the
HVLP or electrostatic.
(iii) Whenever the approach in either subparagraph
(i) (2) (i) or (i) (2) (ii) is used, t he operator shall
calculate both the organic HAP and VOC emission reduction
using equation 13:
Eq. 13
p =
where
P = organic HAP or VOC emission reduction, percent.
EL = organic HAP or VOC emissions, in pounds, before
the alternative application technique was
implemented, as determined under paragraph
(i) (2) (i) of this section.
Ea = organic HAP or VOC emissions, in pounds, after the
alternative application technique was implemented,
as determined under paragraph (i) (2) (i) of this
section.
ii
"(3) Each owner or operator seeking to demonstrate that an
alternative application method achieves emission reductions
equivalent to HVLP or electrostatic application methods
shall comply with the following:
(i) Each coating must be applied such that the dried film
thickness is within the range specified by the applicable
specif ication (s) for the aerospace vehicle or component
being coated.
11-59
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(ii) If no such dried film thickness specification(s)
exists, then the owner or operator must ensure that the
dried film thickness applied during the period when HVLP or
electrostatic equipment is used is equivalent to the dried
film thickness applied during the alternative application
method test period for similar aerospace vehicles or
components.
(iii) Failure to comply with these dried film thickness
requirements will invalidate the test results obtained under
paragraph (i)(2)(i) of this section."
Response: It would be difficult, but not necessarily
impossible, to conduct this type of spray gun comparison in a
laboratory setting. The lab setting would have to simulate the
production environment in terms of equipment, parts to be coated,
coatings used, and process parameters such as air flows and
temperatures, which might affect the emissions.
It might be a good idea for the facility to conduct a
laboratory study with a smaller application system before
installing a production scale system in the plant. However,
there is a chance that the results of the lab study may not
correlate with the results of full scale production trials.
In addition, the final rule has deleted the 90-day testing
requirement. The EPA revised this provision to add flexibility
to the rule. The revised provision specifies that HAP and VOC
emissions shall be determined for an initial 30-day period, the
period of time required to apply coating to five completely
assembled aircraft, or a time period approved by the permitting
agency.
Comment: Four commenters (IV-D-29, IV-D-33, IV-D-35, IV-D-
52) stated that the EPA referred to the SCAQMD's initiative in
conjunction with CARD to develop a test protocol to measure the
transfer efficiency of spray application equipment. Commenter
IV-D-33 expects the protocol to be completed in 1995 and
encouraged the EPA to use it to develop a spray equipment
certification program. The commenter believes that an equipment
certification program would:
11-60
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1. allow spray technologies to be objectively compared,
2. shift the burden of demonstrating transfer efficiencies
from the operator to the manufacturer, and
3. simplify enforcement.
The commenter offered to provide assistance and technical support
in the development of such a program.
Commenter IV-D-35 noted that the test protocol would
represent an alternative method of qualifying application
equipment for use under the proposed standard. In response to
the EPA's request for comment from those familiar with the test
protocol for transfer efficiency, the commenter conferred with
the prime contractor under contract to the SCAQMD providing the
laboratory testing. The contractor's response to this inquiry
provided a comparison between the CARB/SCAQMD project and the
proposed Aerospace NESHAP. The commenter believes that it is
important that the EPA take the differences in the application of
the CARB/SCAQMD transfer efficiency test protocol and the
aerospace production line tests into consideration when setting a
standard for the aerospace industry.
The commenter pointed out that the CARB/SCAQMD study would
test spray guns under simulated production conditions, whereas
the aerospace rule would test under normal operating conditions.
Also, the CARB/SCAQMD project would use very well-defined
coatings, whereas in the aerospace rule, facility coatings would
be used. The commenter also noted that the CARB/SCAQMD project
would apply coatings using automated equipment, whereas painters
would apply the coatings in the aerospace production line tests.
The commenter suggested that the transfer efficiency will vary
from painter to painter, so overall efficiency will be affected
due to the many painters involved. The commenter claimed that
under the CARB/SCAQMD approach, experimental errors will be
minimized due to the lack of painter involvement. In contrast,
the commenter claimed that the difference in spray painters
cannot be avoided under the aerospace production line tests.
The commenter also pointed out that laboratory conditions can be
controlled under the CARB/SCAQMD study effort and environmental
11-61
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conditions cannot be controlled in the aerospace line tests.
Also, the commenter suggested that the CARB/SCAQMD protocol is
intended to allow ratings for individual model spray guns and not
simply generic types (e.g., HVLP, electrostatic, etc.); in
contrast, the EPA protocol would be used for a specific gun model
for a specific coating, under a unique scenario. The commenter
claimed that the EPA approach is not as cost-effective as the
CARB/SCAQMD approach. According to the commenter, the key issue
under the aerospace production line approach would be the
difference in spray painter application techniques and the total
emissions that result from the painting operations. The
commenter stated that in the CARB/SCAQMD approach, the dry film
thickness is taken into account, along with the size of the total
spray envelope. Also, the aerospace line production approach
involves three-dimensional parts, whereas the CARB/SCAQMD
approach targets flat panels.
Response: [Response to be added after discussion with
Emission Measurement Branch.]
11.8 HAP CONTENT DETERMINATION - ALTERNATIVE PROCEDURE
Comment: Commenter IV-D-30 noted that the proposed rule
would require the operator to submit an alternate procedure for
determining HAP content for approval by the EPA if the organic
HAP content of a primer, topcoat, or stripper is unavailable from
the manufacturers' formulation data. The commenter believes this
could result, depending on the method proposed, in widely varying
analytical data. According to the commenter, this imposes an
unreasonable burden upon the user, particularly small companies
or organizations. The commenter recommended that the EPA specify
a method for determining organic HAP content.
Commenter IV-D-29 stated that requiring a user to determine
the HAP content of materials where the manufacturer fails to do
so is inappropriate. The commenter pointed out that no test
methods are specified for the user to make such a determination.
In addition, commenter IV-D-32 recommended that explicit language
be added allowing owners/operators to rely solely on
11-62
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manufacturer's data. The commenter also recommended that these
provisions be extended to chemical strippers.
Commenter IV-D-27 believes that asking the user to determine
the chemical components of a stripper is unreasonable. The
commenter stated that in many cases the constituents in a
stripper are proprietary and cannot be reverse engineered to
determine quantities. According to the commenter, when
components are identified in the MSDS or by the vendor, precise
quantities are not typically revealed and at times are in ranges.
The commenter believes that the vendor should be responsible for
determining that their products are in compliance with the
provisions in the Aerospace NESHAP. According to the commenter,
from a cost savings view, the vendor would absorb and pass on the
cost of laboratory testing eliminating numerous aerospace
companies from performing duplicative tests.
Commenter IV-D-27 recommended the following revision to
§63.750(j) :
"(j) Organic HAP content of chemical strippers. The organic
HAP content of chemical strippers used in depainting
operations subject to §63. 746 (b) (1) shall be determined from
manufacturer's formulation data. The manufacturer must
certify the HAP content when used according to the
manufacturer's instructions. -3rf — the organic HAP content can.
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Response: As previously discussed in Section 11.1, this
rule requirement will have the effect of causing coating
manufacturers to analyze coatings in accordance with the
specified methodologies and to make these analyses available to
coating users.
The EPA included the provision which requires a facility to
submit an alternative procedure for approval because all
manufacturer's may not supply the needed information. The EPA
will carefully consider any method or documentation submitted for
11-63
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approval. However, the EPA does not anticipate that any such
methods or documentation will be received from the industry.
Coating vendors that choose to not provide the needed information
to their customers will probably find that demand for their
products is severely reduced, especially when the customers must
determine parameters that could be easily determined by the
coating manufacturer.
11.9 GENERAL COMMENTS
Comment• A commenter stated that the regulation as proposed
requires the use of an outdated test method (ASTM E 260-85) for
vapor pressure determination. According to the commenter, the
proposed method would violate current MIL-STD-100 requirements,
which state that current revisions of ASTMs must be used. The
commenter pointed out that ASTM test methods are generally
revised when deficiencies are found in the earlier version of the
test method, or because improvements can be made to that earlier
version. The commenter claimed that it is customary to specify
an ASTM method without a version number or to say, "the current
version of" ASTM E XXX, rather than to lock in a particular
version, even if that version is current at the time.
Response: As discussed in Section 11.2, the final rule
includes the commenter's recommendations and refers to ASTM
methods as "most current version of ASTM E 260-**."
11-64
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12.0 MONITORING REQUIREMENTS
12.1 PRESSURE DROP PARAMETER FOR PARTICULATE FILTERS
Comment: Two commenters (IV-D-14, IV-D-33) believe that
pressure drop is an appropriate parameter for compliance
determinations for dry particulate filter system performance.
Four commenters (IV-D-11, IV-D-35, IV-D-42, IV-D-05) expressed
the opinion that pressure drop is not an appropriate parameter
for compliance determinations.
Commenter IV-D-14 pointed out that with any piece of
technical equipment there will be variations in the limitations
of an effectively run piece of control equipment. If there is a
concern about the possibility of a wide range of variations, the
commenter suggested that a survey be conducted to relate the
variations in pressure drop to the effectiveness of the filter so
that conclusions can be drawn as to what types of dry particulate
filters, waterwash systems, and maximum/minimum pressure drops
would be acceptable for a typical well-maintained system.
Commenter IV-D-37 claimed that filter pressure drop is not a
completely reliable and precise indicator of control performance
relative to operations in the short term.
Commenter IV-D-11 stated that pressure drop is not a valid
compliance tool for dry filter systems since filter performance
is based on the particulate cake thickness and because of
variability among manufacturers' specifications.
Commenter IV-D-11 noted that baghouses and cartridge filter
units used in controlling abrasive blasting emissions are
equipped with automatic mechanical or pneumatic cleaning devices,
and action is initiated from a cycle-timer or from pressure drop.
Therefore, the commenter stated, a pressure drop limit would be
12-1
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appropriate since most of these units come equipped with a
pressure drop indicator such as a magnehelic or photohelic gage.
The commenter stated that there is some variation in acceptable
pressure drops among different filter media, but the normal high
and low limits are approximately 6 inches water gauge (W.G.) and
2 inches W.G., respectively.
Commenter IV-D-42 believes that the use of pressure drop as
a monitored parameter may result in different levels of
compliance depending on the manufacturer, as suggested by the
EPA. According to the commenter, it is not clear, however, what
efficiency is sought or attained by this requirement. The
commenter said that they do not have an alternative to suggest at
this time.
Two commenters (IV-D-5, IV-D-35) noted that pressure drop
can be used as an indication that maintenance is needed.
According to two commenters (IV-D-5, IV-D-ll), particulate
control devices generally become more efficient as the cake
builds up on the face of the dry filter media. Commenter IV-D-ll
stated that if the cake thickness and the associated pressure
drop become too great, there is a problem with the media being
pulled from the frame and the overspray passing around the edge
of the filter. The commenter stated that this usually occurs at
pressure drops much higher than the manufacturer recommends.
Commenter IV-D-35 pointed out that it is important that the
enclosure, booth, or hangar be designed to handle the maximum
flow of paint spray as an initial condition of permitting. If
not, the commenter claimed, the airborne inorganic HAP will flow
outside the airstream to the filters, resulting in ineffective
capture.
Commenter IV-D-5 stated that pressure drop does not
necessarily indicate anything about the amount of particulate
(inorganic HAP) on the exit side of the filter. The commenter
also stated that in a blasting operation, the particle size of
the blasted material containing the HAP will have a Gaussian
distribution and the filter may trap the large and intermediate
12-2
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size particles but allow the small particles to pass through,
especially when the pressure drop is low.
Additionally, commenter IV-D-35 pointed out that appropriate
pressure drop data are generated by the filter manufacturer, not
the booth manufacturer. The commenter, therefore, recommended
that the filter manufacturer be cited in the NESHAP to specify
the proper reference for particulate filter efficiency data.
Four commenters (IV-D-27, IV-D-29, IV-D-35, IV-F-1.2) stated
that a pressure drop measurement across a waterwash spray booth
is not an indicator of a change in particle removal efficiency.
Commenter IV-D-29 stated that a major waterwash booth
manufacturer advised them that application of a differential
pressure gauge is inappropriate for waterwash systems. This is
because a wet booth relies upon the scrubbing action of the air
stream passing through the water curtain to accomplish
particulate removal, rather than passing through fixed media.
The commenter stated that because the water curtain does not
exist as a fixed medium, there is no opportunity to measure
differential pressure across the water curtain.
The commenter claimed that, since the waterwash booth
systems rely on the scrubbing action of the water curtain for
particulate removal, monitoring of particulate removal efficiency
should be done by visual monitoring of the water curtain, if
possible.
The commenter pointed out that within the broad category of
all waterwash booths used in the aerospace industry, there is a
significant variation in the design of the units. The commenter
claimed that in some of these units, the water curtain is not
visible without physical disassembly of the booth. Consequently,
visual monitoring of the water curtain cannot be required for all
waterwash systems. For these cases, the commenter claimed that
consistent particulate removal efficiency can only be assured
through implementation of the manufacturer's maintenance
instructions.
Commenter IV-D-11 stated that waterwash systems can achieve
very high paint overspray control efficiencies as long as the
12-3
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equipment and water are properly maintained. According to the
cornmenter, proper maintenance of the circulating pumps, water
makeup system, spray nozzles, and other equipment has a profound
effect on the system efficiency. The commenter stated that the
preferred indicator of system performance is the water
circulation rate or pressure based on a properly operating
baseline. The commenter noted that circulating water chemistry
has a large effect on system performance. The commenter also
stated that the amount of suspended solids and the level of
additives in solution to control flocculation are indicators of
system performance. The commenter, therefore, recommended that
the measurement of these factors to establish compliance be
included in the final rule.
Commenter IV-F-1 believes that gaps in the water curtain are
highly correlated to the control efficiency. The commenter noted
that most paint booth permits have some kind of requirement or
permit condition which states that a facility may not have gaps
in the water curtain.
Response: The EPA has revised the rule to specify that
topcoat and primer operations and depainting operations that use
dry particulate filters to control inorganic HAP emissions shall
provide for continuous monitoring of the pressure drop across the
filter. In addition, the filter must be operated in the pressure
drop range specified by the filter manufacturer. The EPA
believes that the filter manufacturer should provide the pressure
drop parameters that indicate maximization of their product's
performance.
The EPA acknowledges that pressure drop is not an acceptable
monitoring parameter for waterwash particulate removal devices.
Therefore, a provision has been added to the final rule to
require the inspection of the water curtain on these devices.
The EPA is also requiring that dry particulate filtering
devices and waterwash booths be operated according to the
manufacturer's specifications. This includes scheduled
maintenance procedures. The devices must be shut down when the
pressure drop exceeds the specifications of the device
12-4
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manufacturer or the filter manufacturer or when the water curtain
fails the visual continuity check or exceeds the specified water
flow rate limits.
The standards have been revised to reflect the changes above
and additional changes concerning the operation and control
efficiency have also been incorporated. The EPA has revised the
rule as follows:
"63.745 (g) (3) If the pressure drop across the dry
particulate filter system, as recorded pursuant to
§63.752(d)(1), is outside the limit(s) specified by the
filter manufacturer or in locally prepared operating
procedures, shut down the operation immediately and take
corrective action. If the water path in the waterwash
system fails the visual continuity/flow characteristics
check, or the water flow rate recorded pursuant to
§63.752(d)(2) exceeds the limit(s) specified by the booth
manufacturer or in locally prepared operating procedures, or
the booth manufacturer's or locally prepared maintenance
procedures for the filter or waterwash system have not been
performed as scheduled, shut down the operation immediately
and take corrective action. The operation shall not be
resumed until the pressure drop or water flow rate is
returned within the specified limit(s)."
A similar provision has been added to the depainting
operations standard (63.746(b)(4)(v)).
"§63.751(c) Dry particulate filter. HEPA filter, and
waterwash systems - primer and topcoat application
operations.
(1) Each owner or operator using a dry particulate filter
system or a HEPA filter system to meet the requirements of
§63.745 (g) (2) shall continuously monitor the pressure drop
across the system.
(2) Each owner or operator using a waterwash system to meet
the requirements of §63.745(g)(2) shall continuously monitor
the water flow rate through the system."
12-5
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A similar provision has been added to the monitoring
requirements for particulate filters and waterwash booths used to
control emissions from depainting operations (§63.751(d)). In
addition, the recordkeeping requirements have been revised to
reflect the changes in the standards noted above.
12.2 ALTERNATIVE MONITORING REQUIREMENTS
Comment: Commenter IV-D-44 stated that batch plant
monitoring cannot be adequately demonstrated with traditional
monitoring schemes and, therefore, special monitoring is
required. The commenter illustrated this concern by describing
the difficulty they had with using continuous temperature
monitoring of a condenser on a batch reactor, where the readings
did not provide an accurate indication of compliance. The
commenter, therefore, recommended that proposed §63.751(e) be
revised to read as follows:
"63.751(e)(2)(i) Alternative monitoring requirements when
the affected source in infrequently operated; or for batch
type operations.
63.751 (e) (4) (ii) The application shall contain a
description of the proposed alternative monitoring system
and information justifying the owner's or operator's request
for an alternative monitoring method, such as the technical
or economic infeasibility, or the impracticality, of the
affected source using the required method such as for batch
operations."
Response: Batch type operations may be conducted at
facilities any number of times per day, month, or year. As such,
the EPA has proposed the use of an alternative monitoring
procedure to allow facilities an opportunity to apply for an
exemption to the proposed standard. The proposed and final rules
specifically allow a facility to apply for consideration when an
"affected source is infrequently operated." The EPA believes the
standards allow a facility to request alternatives to the
monitoring requirements for many operations, including batch type
operations, if the facility deems an exclusion is needed.
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12.3 CATALYTIC OXIDATION
Comment: Commenter IV-D-4 concurred with the EPA's
conclusion that catalytic oxidation is an available alternative
control strategy. The coinmenter stated that catalytic oxidation
(incineration) technology is a proven, effective technology that
is being used commercially in a wide range of industrial
applications as an effective VOC control, and will prove to be
just as effective in controlling HAP from several of the emission
sources covered by the proposed rule. The commenter stated that
a properly designed catalytic oxidizer can achieve 98-99 percent
destruction efficiency.
Commenter IV-D-12 believes that it is excessive to require
verification of the temperature sensor calibration every 3 months
for incinerators (oxidizers). According to the commenter,
recalibration of temperature sensors, after initial calibration,
should be necessary only if mechanical damage occurs or if there
are indications of incomplete destruction of contaminants. The
commenter noted that, in New Jersey, CEM's for CO and 0: are
normally required for all thermal oxidizers to provide a direct
indication of incomplete combustion.
The commenter referred to the proposed requirement that
temperature differential across the bed of a catalytic oxidizer
be used as a minimum standard, based on a performance test.
According to the commenter, the use of this temperature
differential may lead to a false indication of a permit
violation. The commenter pointed out that the temperature
difference that occurs between the entrance and exit of the
catalyst bed is a function of the type and amount of contaminant
being oxidized in the chamber and that, since these are usually
variable in day-to-day operations, false indications of a
violation may be frequent, especially if the test is performed at
maximum load, as is commonly specified. The commenter believes
that the use of CEM's, either continuously or periodically, is a
better option. For smaller oxidizers, the commenter suggested
that allowing the use of lower cost portable total hydrocarbon
monitors (instead of a full certified CEM) may be appropriate.
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Finally, the commenter suggested that a focused certification
could be developed for monitors used as an indicator of control
device malfunction, rather than an indicator of exact emission
levels.
Commenter IV-D-29 stated that, because monitoring
temperature gives a good indication of incinerator efficiency,
they support the requirements in this section for continuous
monitoring of temperature as a surrogate to determining
destruction efficiency as no other direct method is necessary.
Commenter IV-D-30 suggested that other non-continuous,
lower-cost techniques might be adequate for this purpose and
should be considered. Specifically, the commenter requested that
devices other than continuous strip chart recorders, such as
computers, be allowed. The commenter also recommended the use of
the term "recording device" in place of "recorder."
As a matter of clarity, commenter IV-D-29 preferred that
non-catalytic incinerators be referred to as "thermal
incinerators." The commenter noted that this is consistent with
the wording used in other EPA documents.
The commenter suggested the following language changes in
§63.751(b):
"§63.751(b) (1) All temperature monitoring equipment shall
be installed, calibrated, maintained, and operated according
to manufacturer's specifications. ALL temperature sensors
should be replaced, or have their calibrations verified.
every 3 months.
§63.751(b)(2) Where thermal incinerator is used, a
thermocouple equipped with a continuous recorder shall be
installed and continuously operated in the firebox or in the
ductwork immediately downstream of the firebox in a position
before any substantial heat exchange occurs.
§63.751(b)(4) For each thermal incinerator, each owner or
operator shall establish during each performance test,
including the initial performance test, the minimum
combustion temperature as a site-specific operating
parameter. This minimum combustion temperature is the
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operating parameter value that demonstrates compliance with
§63.745(C)(2) and §63.747(d)(2).
Response: The EPA has determined that continuous emission
monitors (OEM's) are effective in determining the destruction
efficiency of incinerators and will allow the use of CEM's as an
alternative to the required calibration every 3 months. The EPA
has revised the rule as follows:
"§63.751(b)(8) All temperature monitoring equipment shall
be installed, calibrated, maintained, and operated according
to manufacturer's specifications. Every 3 months,
facilities shall replace the temperature sensors or have the
temperature sensors recalibrated. As an alternative, a
facility may use a continuous emission monitoring system
(CEMS) to verify that there has been no change in the
destruction efficiency and effluent composition of the
incinerator."
12.4 CONTINUOUS MONITORING REQUIREMENT FOR PARTICULATE FILTERS
Comment: Four commenters (IV-D-11, IV-D-35, IV-D-37, IV-D-
50) recommended that the pressure drop be monitored once per
shift instead of continuously. Commenter IV-D-29 recommended
daily monitoring. Commenter IV-D-27 suggested deletion of the
word "continuously" from the rule. Two commenters (IV-D-14, IV-
D-33) supported the continuous monitoring requirement for dry
particulate filters.
Commenter IV-D-43 recommended that the regulation provide
local districts the flexibility to propose alternate monitoring
requirements.
Commenter IV-D-50 stated that pressure drop through the
particulate control device is a parameter that changes very
slowly and does not require continuous monitoring.
Commenter IV-D-35 stated that continuous monitoring would
require installation of costly, "real-time" monitoring equipment.
The commenter indicated that they currently have visual "sight
glass" pressure drop indicators on their filtration sufficient to
ensure proper equipment operation. Additionally, the commenter
suggested that this recommendation is consistent with the
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pressure drop recordkeeping requirements identified in
§63.752(d).
According to commenter IV-D-27, the EPA defines continuous
monitoring as measuring emissions or parameters on an extremely
frequent basis and then averaging those results over some period
of time (Federal Register, October 22, 1993, p. 54657). The
commenter then noted that proposed §63.752(d) requires a daily
reading of the pressure drop. The commenter believes that this
could be interpreted to mean extremely frequent readings that
would be averaged to obtain the daily reading. The commenter
claimed that industry would be required to purchase, install, and
maintain costly continuous recorders, such as strip charts, for
the ability to continuously monitor.
Commenter IV-D-37 believes that the "continuously monitored"
requirement is unreasonable. The commenter pointed out that
dedicating a second employee to the operation for the sole
purpose of monitoring filter pressure drop--in effect, doubling
the labor costs for painting and depainting--is disproportionate
to the risk of harm resulting from inorganic HAP emissions in the
event that filter efficiency should decrease
slightly during a given painting or depainting operation.
Commenter IV-D-5 recommended that inorganic HAP emissions be
monitored leaving the filter. Commenter IV-D-27 believes a
separate section should be created addressing "waterwash spray
booths."
Three commenters (IV-D-27, IV-D-29, IV-D-35) recommended
visual inspection of the water curtain as a monitoring
requirement. Commenter IV-D-35 suggested that this is a normal
condition incorporated into State/local permits. Two commenters
(IV-D-14, IV-D-35) recommended that visual inspections be
recorded once per shift and commenter IV-D-29 recommended that
visual inspections be recorded daily. Commenter IV-D-37 stated
that recording the pressure drop once per shift is a reasonable
industrial practice, would correspond to the recordkeeping
requirements of proposed §63.752(d) and §63.752(e)(5), and thus
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serve as a routine checklist to ensure that filters are
serviceable.
Commenter IV-D-29 recommended that the EPA allow the
industry to either (1) perform a daily visual inspection of the
water path for continuity/flow characteristics, or (2) where
visual inspections are not applicable, adopt either of the
following as the means of demonstrating compliance for waterwash
booths: (a) daily monitoring of water flow meter readings, or
(b) the booth manufacturer's maintenance procedures.
Commenter IV-D-35 recommended that §63.745 (f) (3) be revised
to read as follows:
"Monitor once per shift the pressure drop across the
particulate filter. Visual inspection of the water curtain
once per shift during operation of waterwash may be used as
a surrogate for pressure drop measurements indicating the
need for waterwash control services."
Commenter IV-D-29 recommended that §63.745(f)(3) be revised
as follows:
(3) ContIITLLOXISjLy nioitx uOir criG pirsssuiTG Qirop siciross ens
particulate filter or waterwash. Each owner or operator
using particulate filters shall daily monitor the pressure
drop across the particulate filter. Each owner or operator
using a waterwash system shall either (1) perform a daily
visual inspection of the water path for continuity/flow
characteristics, or (21 where visual inspections are not
applicable, (a) monitor water flow meter readings daily, or
(b) adopt the booth manufacturer's maintenance procedures."
Commenter IV-D-27 recommended that §63.745(f) (3) be revised
as follows:
"(3) Continuously monitor the pressure drop across the
particulate filter or waterwash. For water curtains,
visually verify the water curtain is on and achieves an even
water distribution."
Commenter IV-D-27 recommended that §63.745 (f) (4) be revised
as follows:
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"(4) If the pressure drop across the parbiculate filter or
the water flow rate of the water curtain as recorded
pursuant to §63.752(d) is outside the normal operating
limit (s) specified by the manufacturer, or the facilities
operating limits, shut down the operation immediately and
take corrective action. The operation shall not be resumed
until the pressure drop or flow rate is returned to the
limit(s) specified by the manufacturer or the facilities
operating limits."
Depainting:
Commenter IV-D-27 recommended the following revision to
§63.746(d) (3) :
"(d)(3) Continuously monitor the pressure drop across the
particulate filter."
Commenter IV-D-35 recommended that §63.746(d)(3) be revised
to read as follows:
"Monitor once per shift the pressure drop across the
particulate filter."
Monitoring:
Commenter IV-D-27 recommended the following revision for
§63.751(c):
11 (c) Particulate filters and waterwash spray booths -
primer and topcoat application operations. Each owner or
operator using particulate filters or waterwash spray booths
in accordance with the requirements of §63.745 (f) (3) shall
continuously monitor the pressure drop across the
particulate filter or waterwash."
Commenter IV-D-35 recommended that §63.751(c) be revised to
read as follows:
"(c) Particulate filters - primer and topcoat application
operations. Each owner or operator using particulate
filters in accordance with the requirements of §63.745(f)(3)
shall once per shift monitor and record the pressure drop
across the particulate filter."
Commenter IV-D-29 recommended that the use of waterwash be
allowed for particulate control. The commenter stated that
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pressure drop is not an appropriate measure for waterwash booths,
and suggested the following revisions:
"§63.751(c) Particulate filters and waterwash spray booths -
primer and topcoat operation. Each owner or operator using
particulate filters in accordance with the requirements of
§63.745 (f) (3) shall daily monitor the pressure drop across
the particulate filters. Each owner or operator using a
waterwash system shall either (1) perform a daily visual
inspection of the water path for continuity/flow
characteristics, or (2) where visual inspections are not
applicable, (a) monitor water flow meter readings daily, or
(b) adopt the booth manufacturer's maintenance procedures.
11
...
"§63.751(d) Particulate filters and waterwash spray booths -
depainting operation. Each owner or operator using
particulate filters in accordance with the requirements of
§63.746(d)(3) shall daily monitor the pressure drop across
the particulate filters. Each owner or operator using a
waterwash system shall either (1) perform a daily visual
inspection of the water pa,th for continuity/flow
characteristics, or (21 where visual inspections are not
applicable, (a) monitor water flow meter readings daily, or
(b) adopt the booth manufacturer's maintenance procedures."
Commenter IV-D-27 recommended the following revision for
§63.751(d):
"(d) Particulate filters - depainting operation. Each owner
or operator using particulate filters in accordance with the
requirements of §63.746(d)(3) shall continuously monitor the
pressure drop across the particulate filters."
Commenter IV-D-35 recommended that §63.751(d) be revised to
read as follows:
"Particulate filters - depainting operation. Each owner or
operator using particulate filters in accordance with the
requirements of §63.746(d)(3) shall once per shift monitor
and record the pressure drop across the particulate
filters."
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Commenter IV-D-29 believes that revisions are necessary in
the recordkeeping requirements for the inorganic HAP control
equipment. The commenter recommended the following revision for
§63.752(d):
"§63.752(d) Primer and topcoat operations - Inorganic HAP
emissions.
(1) For particulate filters. Each owner or operator
seeking to comply with §63.745 (f) for control of inorganic
HAP emissions from primer and topcoat applications shall
record the actual pressure drop across the filters once each
day during which coating operations occur. This log shall
include the acceptable limit(s) of the pressure drop as
specified by manufacturer or certified by the operator.
(2) For waterwash booths each owner or operator seeking to
comply with S63.745(f) for control or inorganic HAP
emissions from primer and topcoat applications shall record
the results of either the visual inspection of the water
path's continuity/flow characteristics during which coating
operations occur or where visual inspections are not
applicable the (a) daily water flow meter readings or (b)
maintain a record of any maintenance conducted pursuant to
the booth manufacturer's maintenance procedures."
Commenter IV-D-29 recommended deleting §63.752(e)(5)(ii) and
revising §63.752(e)(5)(i) as follows:
"(5)(i) Inorganic HAP emissions. For particulate filters.
The actual pressure drop across the filter once per shift
day in which the depainting process is in operation. This
log shall include the acceptable limit(s) of the pressure
drop as specified by manufacturer. For waterwash booths,
the results of either the visual inspection of the water
path's continuity/flow characteristics one per day during
which the depainting process is in operation or where visual
inspections are not applicable the (a) daily water flow
meter readings or (b) record of any maintenance conducted
pursuant to the booth manufacturer's maintenance
procedures."
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Response: The EPA does not intend for facilities to record
the monitored parameter "continuously." The monitored parameter
must be recorded once per shift. A mechanical monitoring device,
such as a bell, alarm, whistle, etc. may be installed to notify
the supervisor in the event of emissions system failure. In no
way should this requirement be construed as meaning that a person
or monitoring device must continuously record the parameter.
12.5 REDUCTION OF MONITORING DATA
Comment:: Commenter IV-D-35 stated that the EPA's intention
in the "reduction of monitoring data," §63.751(f)(1), is not
clear. The commenter asked if it is the EPA's intent that raw
data need not be recorded, even when the raw data are used to
determine a "reduced" parameter that is required to be recorded.
Response: The EPA requires that all data necessary for a
facility to determine compliance with the rule must be recorded,
including the raw data used in the calculations. The data must
be recorded, at a minimum, in the same number of significant
digits as specified in the reporting standard for the parameter.
The parameter may be recorded in more significant figures than is
specified in the reporting standard. However, when the parameter
is reported, the data must again be in the same number of
significant figures specified in the rule for that parameter.
12.6 GENERAL COMMENTS
Comment•• Commenter IV-D-43 recommended that, in order to
ensure continuous compliance with the overall control efficiency
requirements, control devices should meet the requirements in the
enhanced monitoring program (EMP) regulation proposed by the EPA.
Response: The EPA believes that the final rule contains a
sufficient number of compliance issues for facilities, and that
the monitoring requirements provide adequate safeguards to ensure
that compliance with the standards will be continuously achieved.
Additional monitors on control devices would add to the
compliance costs in the areas of material and personnel without
an attendant further decrease in emissions or increase in
enforceability. For these reasons, enhanced monitoring
provisions are not being specified under this NESHAP.
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13.0 RECORDKEEPING AND REPORTING REQUIREMENTS
13.1 GENERAL COMMENTS
Comment: Commenter IV-D-12 stated that recordkeeping should
be kept to a minimum. The commenter recommended that the EPA
prepare model reporting forms each type of operation (e.g.,
solvents used in hand-wipe cleaning, solvents used for exempt
hand-wipe cleaning, leaks from enclosed spray gun cleaning,
depainting operations). The commenter believes that this will
provide a useful tool, reveal ways in which the reporting
requirements could be simplified, and assist State and affected
sources in the implementation of the reporting requirements.
Response: The EPA has attempted to specify records only for
instances where they are necessary as a tool for the Agency in
enforcing the standards. The EPA will work with the industry and
local permitting agencies to determine if standardized forms are
necessary and if the forms can be designed to include all
potential facility situations.
Comment: Two commenters (IV-D-33, IV-D-43) stated that they
commend and support the reduced recordkeeping and reporting
requirements in the proposed NESHAP. Commenter IV-D-33 believes
that the reduced requirements provide a valuable incentive to
utilize materials and processes that minimize toxic air
emissions.
Commenter IV-D-34 stated that reporting requirements in the
aerospace NESHAP should be kept as is or made more stringent.
The commenter stated that their visits and compilation of
comments from numerous companies throughout the U.S. indicate
that without some form of inducement such as the recordkeeping
requirements, the change to environmentally friendly technology
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will move at a slow or no pace. The commenter pointed out that
one company in Texas as well as several military installations
are currently complying with recordkeeping requirements;
therefore, the commenter feels the argument for not requiring or
reducing requirements for recordkeeping is a moot point.
Commenter IV-D-31 recommended that all supervisors be
required to record all violations of the housekeeping standards
and report them. The commenter also recommended that, if
supervisors witness no violations and receive no reports of any
from subordinates, they must certify each reporting period that
no violations occurred of which they were aware. The commenter
believes the Act requires no less.
Four commenters (IV-D-27, IV-D-29, IV-D-35, IV-D-37) believe
that the recordkeeping and reporting requirements are burdensome,
often duplicative, do not contribute to the protection of the
environment, and, in some instances, have no practical utility.
Commenter IV-D-29 believes that the recordkeeping and
reporting requirements violate the Paperwork Reduction Act (PRA).
The commenter pointed out that the PRA is intended to minimize
the Federal paperwork burden imposed on individuals, businesses,
and others as a result of information collection requests issued
by Federal agencies (44 U.S.C. §3501). The commenter noted that
an "information collection request" is defined in the Act to
include regulations, application forms, questionnaires, and other
recordkeeping or reporting requirements (44 U.S.C. §3502(11)).
The commenter stated that the PRA adopts a two-pronged
approach to reduce the burden created by information collection
requests. The first prong relies upon self-evaluation by the
agency seeking information. The commenter stated that the Act
requires that each agency review its proposed regulations and
other information requests to ensure that the information being
sought is not available from some other source within the Federal
government. The commenter also added that agencies are directed
to evaluate their proposed information collection requests to
make certain that the burden on persons who will be reporting is
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reduced "to the extent practicable and appropriate." (44 U.S.C.
§3507(a)).
According to the commenter, the second prong relies on the
Office of Management and Budget (OMB) to review proposed
information collection requests to ensure that the requests are
consistent with the purposes of the Act. The commenter stated
that OMB is directed to evaluate each information collection
request proposed by an agency to determine whether the collection
of information "is necessary for the proper performance of the
functions of the agency" and whether the information will have
"practical utility" (44 U.S.C. §3508). The commenter also noted
that the Act provides that "[t]o the extent, if any, that [OMB]
determines that the collection of information by an agency is
unnecessary, for any reason, the agency may not engage in the
collection of the information." The commenter claimed that in
this proposed rule, the EPA cannot meet its burden for important
parts of recordkeeping and reporting requirements that accompany
the proposed control standards.
Commenter IV-D-32 recommended that an explicit exclusion
from all recordkeeping and reporting requirements for activities
using solvents at laboratories or in research and development and
quality assurance activities be included. According to the
commenter, these are minor sources that do not have significant
emissions.
Commenter IV-D-37 stated that employees at airline
maintenance facilities may be required to perform dozens of
maintenance activities throughout the hanger area, utilizing
multiple maintenance processes and chemicals. The commenter
claimed that daily recordkeeping requirements, in particular,
would be enormously expensive and would effectively transform the
duties of skilled mechanics into those of data recorders. The
commenter recommended that wherever possible, the rule allow for
facility-wide recordkeeping based on inventory withdrawal
records.
Commenter IV-D-35 recommended that the duplication of
recordkeeping requirements, such as annual or semiannual reports
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of change in coatings or formulations used, be eliminated.
According to the commenter, if other regulations (e.g., title V
operating permits) require similar information, then the
requirement should be deleted from the proposed aerospace rule.
The commenter believes that this recommendation is consistent
with the CAAA emission standards (section 112(d)(2)) requiring
the Administrator to establish such standards "taking into
consideration the cost of achieving such emissions reduction
requirements..." and as also defined under section 112 (f), which
also requires the Administrator to take "into consideration
costs, energy, safety, and other relevant factors, an adverse
environmental effect" when establishing requirements and setting
standards.
Commenter IV-D-29 stated that in certain cases, the EPA goes
beyond the reporting requirements for title V operating permits
which only require semiannual reports of monitoring parameters
and instances of non-compliance.
Commenter IV-D-49 recommended that the EPA review
§63.752(b)(l)(i), (b)(3), and (c)(2) to determine if the section
contains excessive reporting requirements. The commenter claimed
that the semiannual reporting requirement in §63.752(b)(1) on new
cleaning solvents containing no HAP appears to be unnecessary
since the purpose of the regulation is to control HAP. The
commenter also stated that the requirement to keep monthly
records of volumes of compliant solvents in §63.752(b)(3) and
compliant coatings in §63.752(c)(2) may be excessive. The
commenter recommended that the EPA consider whether annual
compliance certification would be sufficient for a source using
compliant solvents and coatings.
Three commenters (IV-D-27, IV-D-29, IV-D-35) believe that
semiannual reporting is unduly burdensome and only annual reports
should be required. Commenter IV-D-27 claimed that when
compliant coatings are used, an annual listing of the coatings
and their respective HAP and VOC content and monthly records for
averaging should give the EPA the information required to
determine compliance.
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Commenter IV-D-35 stated that when a facility is using
compliant material, less stringent recordkeeping, if any, should
be required. The commenter recommended that the EPA require
reliance on the manufacturer's certification of compliant
materials and the supplier's labeling to the maximum extent,
relieving the burden faced by individual facilities from
redundant and expensive testing. The commenter claimed that once
compliance is established, daily and monthly recordkeeping should
not be required. The commenter pointed out that procurement
records could be used to establish maximum usage rates or actual
shop logs if absolutely necessary. The commenter recommended
annual reporting when compliant coatings and cleaning solvents
are used.
The commenter also recommended that the daily compliance
recordkeeping requirement for primers and topcoats be eliminated.
The commenter also stated that the depainting and maskant
operational recordkeeping requirements should be eliminated. In
addition, the hazardous waste storage and handling recordkeeping
provisions should be eliminated because they are duplicative.
Response: Recordkeeping and reporting requirements
associated with research and development activities and quality
control for cleaning solvents, topcoats, primers, and chemical
milling maskants have been deleted from the final rule. In
addition, cleaning solvents that contain no HAP or VOC are
exempted from the standard and therefore, exempted from the
recordkeeping and reporting requirements.
In the proposed rule, daily records were required for the
volumes of non-compliant cleaning solvents used in exempt
operations, as well as of the HAP and VOC contents of "averaged"
primers, topcoats, and chemical milling maskants. The EPA
believes that these records are not excessive and that they are
necessary to determine compliance with the standards and to
monitor the usage of non-compliant materials. However, in order
to add flexibility to the rule and to address attainment areas,
the EPA has changed the daily averaging requirement to monthly
averaging periods or as determined by the permitting agency. In
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no case will the averaging period exceed 30 days. The EPA will
require that the recordkeeping associated with averaging be
recorded on a monthly basis, regardless of whether or not the
permitting agency requires the facility to use shorter averaging
periods. The EPA believes that this revision will reduce the
amount of time required for recordkeeping and still ensure that
the environment is protected. Additional records are required
over the minimum time periods needed to determine compliance.
The frequency for reports has been based on the general
semiannual reporting frequency specified in the General
Provisions.
The final rule was submitted to OMB for review. The Agency
does not wish to cause a facility to needlessly duplicate
information that may already be required in an operating permit
required under the EPA's part 70 (title V) permit program.
§63.753(a)(2) allows such a permit to be submitted in lieu of the
initial notifications required under §63.9(b)(2) of the General
Provisions, provided that the same information is contained in
the permit application as required by §63.9(b)(2). There may be
additional information required to be reported under the NESHAP
that a facility has already compiled for other reasons. The EPA
has no objection to a facility including this information
(assuming that the format is compatible) in the reports or
records that are needed to assure compliance with this NESHAP.
13.2 NOTIFICATION OF COMPLIANCE STATUS
Comment: Commenter IV-D-31 recommended that a facility's
initial notification (General Provisions, §63.9(b)) be required
within 3 months of promulgation. The commenter claimed that
determining whether a facility is covered by this rule is not
complicated. The commenter believes initial notification within
3 months will allow the permitting agencies and the public an
opportunity to work with affected sources.
Additionally, commenter IV-D-31 recommended that the
notification of compliance status be filed with a permit
application within 6 months after promulgation in order to allow
for compliance within 1 year, in most cases. The commenter
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claimed that extensions of the 3-year limit should only be
available if compliant coatings are unavailable for a given
application and control devices cannot be installed in their
stead.
The commenter also recommended that the notice of compliance
status indicate clearly whether or not the source plans to use
averaging for each line along with the types and quantities of
coatings they plan to use.
Commenter IV-D-33 stated that sources should provide copies
of notifications or other required communications to both the EPA
and the applicable State or local control agency. According to
the commenter, since authorized State and local control agencies
will be receiving copies of each notification from these sources
when the applicable title V permit is approved, it is consistent
to keep control agencies apprised of notifications prior to final
approval of title V permit programs. The commenter also stated
that sources should not be required to send the EPA copies of
each notification after a State title V permit has been approved.
Response: Under the General Provisions to part 63
(§63.9(h)(2)(ii)), each notification of compliance status (NCS)
is required to be submitted within 60 days following the
completion of a specified compliance demonstration activity (such
as a performance test). The proposed NESHAP, in §63.753(a) (1),
required a NCS that included information on whether the source
has operated within the specified ranges of its designated
operating parameters. This report was due no later than 12
months prior to the final compliance date (3 years), or within 2
years after promulgation.
The EPA agrees that this notification (submitted at the 2-
year point) should inform the Agency of the facility's plan with
respect to its use of coatings. Therefore, §63.753(a)(1) has
been revised to require this additional information to be
included.
The Agency will not require, under this NESHAP, that
required reports also be sent to State and local control
agencies. Agencies to which enforcement authority has not been
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delegated by the EPA may arrange with their regional EPA office
to procure such reports. Even after permit programs have been
approved under part 70 (title V), the EPA needs to continue
receiving the part 63 (NESHAP) reports in order to monitor the
performance of affected sources as well as the States' success in
implementing this regulation.
Comment: Commenter IV-D-29 requested confirmation of their
understanding that under this rule and the General Provisions,
reports that are prepared under State and local regulations and
that contain essentially the same information as required in the
Aerospace NESHAP will also meet the reporting requirements
contained in the NESHAP.
Response: As discussed above, proposed §63.753(a)(2) has
been retained in the final rule and does allow operating permit
information prepared under part 70, as well as other information
that is similar and in a compatible format, to be submitted as
part of the required NESHAP submittals.
13.3 RETENTION OF RECORDS
Comment: Commenter IV-D-33 pointed out that the proposed
rule requires records to be retained for 5 years. The commenter
stated that the local agencies in California inspect facilities
more frequently than the EPA (for example, most sources in
California are inspected annually). The commenter believes that
flexibility should be provided to States and local agencies to
allow alternative periods of record retention based upon
inspection frequency. The commenter, therefore, recommended that
the rule be modified to require records to be retained for 2
years or until the next inspection, whichever is longer.
Response: The 5-year record retention period reflects the
holding period included in the General Provisions, §63.lO(b)(1) .
The EPA does not believe that a shorter period would be justified
for the aerospace source category. Further, the occurrence of an
inspection at a facility is not considered an appropriate point
in time to discard records.
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13.4 REPORTING PERIOD
Comment: Commenter IV-D-23 noted that the proposed rule
calls for semiannual reporting of monitoring results only if
violations of the standard occurred during the 6-month monitoring
period, while part 70 permitting requirements specify that
monitoring reports must be submitted at least every 6 months,
regardless of whether violations occurred. The commenter
recommended that the EPA ensure that these requirements are
consistent.
Commenter IV-D-12 suggested that the EPA clearly specify in
the regulation the timeframe (e.g., immediately, monthly,
semiannually) required for reporting non-compliance, when a
source deviates from the operating standards or from allowable.
Commenter IV-D-31 stated that the reporting frequency is
inadequate. Specifically, the commenter claimed that reporting
cannot be annual under any circumstances because annual reporting
may make administrative enforcement of violations impossible.
The commenter suggested quarterly reporting, with semiannual
reporting available as a reward for 2 years of compliance with
all applicable emission limitations at a facility. The commenter
noted that annual reporting is inconsistent with the other
reporting obligations of facilities and an insufficient basis for
enforcement. Further, the commenter believes that requiring a
source to submit records every 3 months (or 6 months for those
with clear compliance records) is not a great burden since
records must be kept on a frequent basis.
Commenter IV-D-35 recommended the deletion of proposed
§63.753(d) (2) (ii), which requires annual reports. The commenter
believes that this is a duplicate requirement of the compliance
reports required by a title V permit. The commenter stated that
compliance reports for this NESHAP are not necessary.
Response: Proposed §63.753 (c) (1) (iii) and (v) required only
that each exceedance of the established operating parameter(s) be
reported in semiannual reports. Under §70.6(a)(3)(iii)(A) and
under §63.10(e)(3) of the General Provisions, semiannual reports
on monitoring system results are also required. §63.lO(e) (3) (C)
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requires quarterly reports only if "excess emissions" are
experienced. The EPA has decided to revise this provision as
proposed so that it will be consistent with the General
Provisions. In the final rule, §63.753(c) requires semiannual
reports of operating parameter data from control devices used in
primer and topcoat application operations. Also reported on a
semiannual basis will the facility's statement that its
operations have been in compliance over the previous 6 months.
This requirement is in addition to the reports that provide
specific information on HAP and VOC flow through the facility and
on control system performance. The EPA believes that these
semiannual reports are appropriate. Further, as stated
previously, statements and information submitted under part 70
operating permits may be submitted or included where the
information required in this NESHAP has already been compiled.
13.5 RCRA AND NON-RCRA WASTE
Comment: Commenter IV-D-11 supported the EPA proposal to
require separate lists for those wastes that are subject to RCRA
and those which are subject to the proposed rule as an aid to
monitoring and compliance.
Four commenters (IV-D-27, IV-D-29, IV-D-35, IV-D-35) stated
that the recordkeeping and reporting requirements for waste
handling and storage operations duplicate existing RCRA
regulations. Specifically, two of the commenters (IV-D-27, IV-D-
29) stated that §63.752(g) and §63.753 (f) are duplicative of 40
CFR §262.40(c) and 40 CFR §262.41-44 and would result in
duplicative proof of compliance. The commenters pointed out that
having duplicative requirements under RCRA and the CAA could
subject the generator to multiple violations of the regulations
for a single reporting or recordkeeping error. Commenter IV-D-29
supported the provision in §63.741 (e) which proposes to exclude
all wastes regulated under subtitle C of RCRA from a handling and
storage requirement. Two commenters (IV-D-27, IV-D-29) believe
that the independent reporting requirement for the RCRA status of
waste could not be defended under the Paperwork Reduction Act.
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Commenter IV-D-10 stated that this NESHAP is not intended as an
enforcement mechanism for RCRA.
Additionally, two commenters (IV-D-29, IV-D-35) stated that
the proposed overlap between RCRA and the CAAA adds no
environmental protection yet significantly increases the cost of
compliance. Commenter IV-D-35 stated that the military estimated
that recordkeeping for non-RCRA HAP wastes would raise the costs
of all recordkeeping under the rule by an additional 10-15
percent.
The commenter noted that many States, such as California,
already regulate non-RCRA HAP waste. The commenter suggested
that this rule would either add additional requirements or
preempt those already established by the States. Commenter IV-D-
29 suggested that the EPA confirm that where a State program has
been approved to operate in lieu of the Federal RCRA program, it
will be sufficient for a source to determine whether or not its
waste is hazardous under that program, without investigating its
status under the original superseded Federal regulations.
Commenter IV-D-35 stated that the EPA background documents
and section 114 questionnaires did not address the non-RCRA HAP
waste issue. Furthermore, the commenter remarked that it is
doubtful that the EPA has the factual basis for recommending
further regulation of such wastes, or has considered whether it
should impose such requirements at all. Commenter IV-D-29
pointed out that the EPA has not shown that the proposed waste
stream control measures reflect the average of the best
controlled 12 percent of existing sources, and thus represents
the MACT floor. Commenter IV-D-35 recommended that the EPA
refrain from regulating non-RCRA HAP wastes until it accurately
determines the amount of HAP emissions attributable to industry
waste and the best approach to limit waste, based on economic
analysis.
Commenter IV-D-29 stated that the EPA must provide a de
minimis exemption from the waste storage and handling standards
for non-volatile HAP and that this exemption must be administered
in a reasonable manner. According to the commenter, affected
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sources should be able to rely (at their own risk) on general
knowledge of the process to determine whether or not specific
waste streams exceed the proposed volatility level, just as they
are allowed to rely on general knowledge to make the basic
judgement of RCRA applicability.
Commenter IV-D-32 recommended that all waste regulations be
consolidated in one section of the regulations, preferably the
RCRA regulations.
Commenter IV-D-10 stated that annual reports are adequate to
demonstrate the compliance status with respect to the handling
and storage of waste and that semiannual reports will not enhance
industry's compliance.
Commenter IV-D-27 recommended that proposed §63.752(g) and
§63.753(f) be deleted.
Two commenters (IV-D-29, IV-D-35) recommended that the EPA
eliminate all non-RCRA HAP waste requirements from the rule. The
commenters stated that reporting should not be required for non-
RCRA waste since recordkeeping is not required under this rule
for non-RCRA waste.
Response: As discussed in Section 9.1, the EPA has deleted
the provision requiring enclosure of all waste that contains
organic HAP. The recordkeeping (§63.752(g)) and reporting
(§63.753(f)) requirements related to waste streams have also been
deleted to reflect this change in the standards.
13.6 CLEANING OPERATIONS
13.6.1 Exempt Cleaning Operations
Comment: Ten commenters (IV-D-10, IV-D-12, IV-D-27, IV-D-
29, IV-D-30, IV-D-32, IV-D-33, IV-D-35, IV-D-49, IV-D-50) stated
that the requirements for daily recordkeeping for non-compliant
solvent use in exempt cleaning operations is too labor-intensive
and burdensome.
Six commenters (IV-D-50, IV-D-35, IV-D-30, IV-D-29, IV-D-27,
IV-D-10) stated that requiring the name of the parts and
assemblies cleaned and the associated volume of solvent used does
not provide any useful information to the owner or to the EPA.
Four commenters (IV-D-29, IV-D-35, IV-D-10, IV-D-27) stated that
13-12
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tracking individual parts only increases expenses without any
environmental benefit.
Three commenters (IV-D-27, IV-D-29, IV-D-50) believe that
requiring daily records will actually be less accurate than
monthly or yearly reporting due to overestimation of solvent
usage. Two commenters (IV-D-27, IV-D-29) stated that the most
accurate records come from inventory, procurement records, and
chemical dock receiving records and waste records on a monthly or
annual basis. Commenter IV-D-29 noted that the proposed rule
does not require these types of records for any other operations.
Two commenters (IV-D-29, IV-D-30) stated that the EPA may
have designed these recordkeeping requirements for non-compliant
solvents to provide an incentive for industry to utilize aqueous
or lower vapor pressure solvents. Commenter IV-D-29 suggested
that an EPA staffer said as much during one of the public
meetings on the proposed rule. The commenter pointed out that
such a motive, however, would represent an impermissible use of
EPA's power to require recordkeeping flatly contradictory to the
letter and spirit of the Paperwork Reduction Act.
Commenter IV-D-31 recommended that a record of where non-
compliant cleaners are used be required and that this record not
be limited to particular types of operations. The commenter
believes that this will require that violations be reported, not
just compliance. The commenter requested that, in the event that
only usage in exempt operations is recorded, the amount left in
storage plus the amount used should be required to equal the
amount purchased. The commenter then requested that, where this
is not the case, a penalty based on a violation throughout the
relevant reporting period be assessed and that criminal penalties
be attached to any misrepresentation as to how these exempt
cleaners are used.
Commenter IV-D-50 believes that a more reasonable approach
to the daily recordkeeping requirements would be to require
manufacturers and rework facilities to develop procedures
consistent with the solvent cleaning regulations. The commenter
stated that compliance could be demonstrated by the facility
13-13
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certifying that the procedures for hand-wipe solvent cleaning
were followed during the repainting period. The commenter stated
that occasional audits by agency personnel could be used to
monitor the procedures and the facilities' compliance with these
procedures.
Four commenters (IV-D-27, IV-D-29, IV-D-30, IV-D-32) believe
that monthly recordkeeping is sufficient to provide the EPA with
the data it needs. In addition, commenter IV-D-29 recommended
that §63.752(b)(4) be revised to require records to be kept at
point of issue or equipment-specific/by process instead at point
of use. Commenter IV-D-32 recommended that facilities be given
the option of maintaining these records at either a central
distribution point or at the operation. Commenter IV-D-30
recommended that the user be allowed to list parts,
subassemblies, and assemblies typical of a particular operation,
without the requirement to record actual activities on a daily
basis.
Two commenters (IV-D-27, IV-D-29) recommended the following
revision to §63.752(b) (4) (i) :
"(i) The amount (in gallons) of cleaning solvent used each
month. day at each operation; and"
Commenter IV-D-27 recommended that §63.752(b)(4)(ii) be
deleted as shown below:
"(b)(4) For each cleaning solvent used for the exempt hand-
wipe cleaning operations specified in §63.744(e) that does
not conform to the vapor pressure or composition
requirements of §63.744(b):
\ 11} TriiS p&irCS, £>U,OA.£! ssriuiy-L i6s / Arid ASS&IHOJ. i ss wni en WGITS
cleaned."
In addition, commenter IV-D-29 recommended the following
revision for §63.752(b) (4) (ii) :
(ii) The processes set forth in section 63.744(e) where
these solvents were utilized.
Commenter IV-D-50 recommended a monthly or annual report of
the quantity of solvent used in exempt solvent cleaning
operations as a reasonable requirement.
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Commenter IV-D-10 stated that the documentation that would
be provided for the title V part 70 permit application and the
notification of compliance status under this NESHAP are adequate
to determine that non-complying solvents are used only in non-
exempt operations.
Commenter IV-D-49 recommended that sources should only be
required to provide an initial notification to validate their
exempt status.
Commenter IV-D-12 recommended that sources only be required
to record and report the amount (in gallons) of cleaning solvent
used each day, instead of recording and reporting on all of the
parts or subassemblies cleaned.
Commenter IV-D-35 recommended the deletion of recordkeeping
requirements for exempt cleaning operations.
Commenter IV-D-29 recommended the deletion of recordkeeping
requirements for §63.744(e) (11), exempt cleaning operations for
research and development, production testing, and laboratory
testing.
Two commenters (IV-D-10, IV-D-33) recommended that the data
be made available on an annual basis. Commenter IV-D-10 believes
>
that the submission of data should coincide with requirements for
RCRA and SARA (i.e., annually). Commenter IV-D-33 stated that
solvent usage records should also be supplied to the EPA on an
annual basis for flush cleaning operations and spray gun cleaning
operations.
Response: The EPA has reviewed these comments and the
proposed recordkeeping requirements related to the use of non-
compliant solvents used in exempt hand-wipe cleaning operations.
The Agency has concluded that the daily requirement is
unnecessary, as is the need to identify specific parts that were
cleaned with these solvents. The provisions in §63.752(b)(4)
have been revised as follows:
"(4) For each cleaning solvent used for the exempt hand-
wipe cleaning operations specified in §63.744 (e) that does
not conform to the vapor pressure or composition
requirements of §63.744(b):
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(i) The identity and amount (in gallons) of each cleaning
solvent used each month at each operation; and
(ii) A list of the processes set forth in §63.744(e) to
which the cleaning operation applies.
13.6.2 Compliant Cleaning Solvents
Commenj:: Two commenters (IV-D-29, IV-D-35) were concerned
about the recordkeeping requirements for compliant cleaning
solvents.
Commenter IV-D-35 recommended that §63.752(b)(2)(iii) be
revised to read as follows:
"Annual records of the volume of each solvent used, as
determined from facility purchasing records or usage
records."
The commenter stated that purchase records do not always
reflect annual usage and do not necessarily reflect usage by
contractors at DoD facilities. The commenter stated that
purchase records do not account for the quantity in storage. The
commenter, therefore, recommended that each facility operator
have the option of determining which records work best for them,
thereby minimizing the recordkeeping burden.
Commenter IV-D-29 believes that the annual recordkeeping
requirements of §63.752(b)(2) should be extended to solvents that
gain compliance by meeting the vapor pressure specification in
§63.744(b)(2).
Commenter IV-D-29 stated that semiannual reports for
requirements that are not monitoring parameters or noncompliant
uses is excessive. As an example, the fact that a compliant
solvent is no longer used is not relevant in determining
compliance with the requirements.
Likewise, according to the commenter, the requirement to
report the use of non-HAP containing solvents (which are not
regulated under this rule) is not relevant in determining
compliance with this rule.
The commenter claimed that in proposing annual recordkeeping
for compliant solvents that meet the composition requirement, the
EPA had determined that annual records of the volume of compliant
13-16
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solvent used is sufficient for the source to document compliance
with the aerospace NESHAP and for the EPA to enforce the rule.
The commenter stated that the EPA has not demonstrated that
additional recordkeeping is needed to document compliance or
enforce the rule if the solvents used are compliant by meeting
the vapor pressure requirement of §63.744(b)(2). Additionally,
the commenter claimed that a 6-month report on new compliant
solvents meeting the vapor pressure limitations does not add to
the enforceability of the vapor pressure limitations.
The commenter believes that all cleaning solvents that are
compliant (i.e., satisfy the MACT floor) should have the same
recordkeeping requirements and recommended that §63.752(a) and
(b)(l) read as follows:
"§63.752 Recordkeeping requirements.
(a) General. Each owner or operator subject to this
subpart shall fulfill all recordkeeping requirements
specified in §63.10(a), (b), (d), and (f).
it
• • •
"(b) Cleaning operation. Each owner or operator of a new
or existing cleaning operation subject to this subpart shall
record the information specified in paragraph (b)(1) through
(b)-f3"H5) of this section, as appropriate.
(1) Trie nsLn\c~HAP content, 3.110. u.ocuiueiits.tion snowing th£
c/irg&m c HAP cons titusnts 01 eacric J_ £S.m_ngs 01 v^ntus^d sru
the facility.
(2)(1) For each cleaning solvent used in hand-wipe cleaning
operations that complies with the composition requirements
specified in §63 . 744 (b)-f±t:
(i) The name of each cleaning solvent used;
(ii) All data and calculations that demonstrate that the
cleaning solvent complies with one of the composition
requirements; and
(iii) Annual records of the volume of each solvent used, as
determined from facility purchasing records.
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not cofiijufiy wi tri tris comjc/os it
.L civ^Llx 1 GlU&nt S 1H 3 o 3 . Y44 \Oj \1/ / £X\lt XlO^S COIYVply Wlt.riu.ilS
vapor pressure requirement of §63 . 744 (b) (2) "
Response : The EPA agrees with the comment concerning
§63. 752 (b) (2) (iii) , and has incorporated the suggested change
into the final rule as listed above.
In addition, it was not the EPA's intention to have
facilities track every part that is cleaned as a exempt hand-wipe
cleaning operation. Therefore, 63. 752 (b) (4) (ii) has been revised
as follows:
" (ii) A list of the processes set forth in §63.744(e) to
which the cleaning operation applies."
The Agency also agrees that reports for non-HAP containing
solvents are unnecessary and has deleted non-HAP and non-VOC
cleaning solvents from the standards (see Section 5.2.1).
Finally, §63. 753 (b) (1) (ii) has been revised as follows:
" (ii) A list of any new cleaning solvents used for hand-
wipe cleaning in the previous 6 months and, as appropriate,
their composite vapor pressure or notification that they
comply with the composition requirements specified in
§63. 744 (b) (1) ; "
13.6.3 Spray Gun Cleaning
Comment : Commenter IV-D-29 recommended that the reporting
language for spray guns be modified to require reporting of only
those gun cleaners that leak, have remained in service and have
not been repaired within 15 days.
The commenter recommended that §63 . 753 (b) (l) (i) , (ii) , and
(iv) be deleted. The commenter also suggested the following
revisions to §63. 753 (b) (1) (vi) :
" (vi) Any instance where a leaking enclosed spray gun
cleaner remains unrepaired and in use for more than 15
days . "
Response-. The EPA agrees with this revision and has
incorporated the suggested language change into the final rule.
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13.7 PRIMER AND TOPCOAT APPLICATION OPERATIONS
13.7.1 Averaged Topcoats and Primers
Comment: Four commenters (IV-D-30, IV-D-29, IV-D-35, IV-D-
50) stated that daily records of HAP and VOC content for averaged
topcoats and primers would create unreasonable costs and would
lead to inaccurate data. Commenter IV-D-50 stated that a daily
averaging requirement will mean that every paint booth in a
facility will require an exact coating plan for every day of
production.
Three commenters (IV-D-29, IV-D-30, IV-D-42) recommended
monthly averaging. Specifically, commenter IV-D-42 recommended
that an option for determining compliance be based on a monthly
(or weekly), as well as a daily basis. Commenter IV-D-29 also
recommended that the compliance period in §63.749(d) be changed
to monthly. Commenter IV-D-30 added that the mixtures used in
facilities typically do not vary on a daily basis and monthly
averaging is thus warranted. Commenter IV-D-42 believes that
this provision may be unnecessarily burdensome for large
facilities with multiple application stations and where different
coatings may of necessity be scheduled for application on
separate days.
Commenter IV-D-35 concluded that only quarterly records for
averaging should be required. According to the commenter,
quarterly comes from the title V operating permit requirements.
The commenter also stated that monthly is more acceptable than
daily recordkeeping. According to the commenter, these records
will give the EPA the information that is needed to determine
compliance as monthly volume-weighted average gives more accurate
information on facility usage and emissions.
Commenter IV-D-35 recommended that §63.752(c)(3)(i) be
revised to read as follows:
"For primers and topcoats complying with the organic HAP or
VOC content by averaging:
(i) The quarterly volume-weighted average..."
Commenter IV-D-29 recommended that §63.752 (c) (3) (i) be
revised to read:
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"§63.752(c)(3) For primers and topcoats complying with the
organic HAP or VOC content by averaging:
(i) The daily monthly volume-weighted average masses..."
Response; The daily averaging period was selected for
consistency with the averaging period in the ambient standards
for ground-level ozone. Since ozone concentrations are affected
through diurnal photochemical reaction cycles by atmospheric VOC,
the time periods over which higher VOC emission rates are allowed
to occur assumes great importance. If a period longer than 24
hours is selected, the chance of violations of the ambient
standards could be increased. Since approximately 95 percent of
the affected aerospace facilities will be in ozone nonattainment
areas, the EPA wishes to ensure that the averaging approach in
the final rule does not contribute to unacceptable ozone
increases. However, in order to provide facilities located in
attainment areas with additional flexibility, the EPA has changed
the averaging requirement from daily demonstrations of compliance
to monthly demonstrations of compliance. The permitting agency
may require an averaging time period shorter than 30 days and in
no case may the averaging time period exceed 30 days. The final
rule also specifies that monthly records of the volume-weighted
masses must be recorded for each topcoat, primer, and chemical
milling maskant used in an averaging scheme. In addition, this
added flexibility will give the local and state implementing
agencies more autonomy in determining the NESHAP compliance with
local and state air quality control programs.
13.7.2 Compliant Topcoats and Primers
Comment: Two commenters (IV-D-29, IV-D-35) stated that
monthly recordkeeping of compliant primers and topcoats is
burdensome and does not provide the EPA with any useful
information.
Commenter IV-D-35 recommended that §63.752(c)(2)(iii) be
revised to read as follows:
"(iii) The volume (gallons) of each coating formulation
within each coating category used annually or according zc
the title V operating permit requirement."
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Commenter IV-D-29 recommended the following change:
" (iii) The volume (gallons) of each coating formulation
within each coating category used each month annually."
Response: The EPA believes that monthly records of
compliant coating use should not create an unreasonable burden on
facilities, and has retained this time period in the final rule.
Comment: Commenter IV-D-76 requested clarification from the
EPA as to whether the proposed reduced recordkeeping for primers
having a VOC content of 250 g/1 applies to exclusive use or when
the primer is used as part of an average. The commenter strongly
recommended that no reduction in recordkeeping be allowed when
the primer is used in averaging of emissions.
Commenter IV-D-79 supported the reduced recordkeeping
requirements for the 250 g/1 VOC primer. The commenter stated
that the EPA has correctly determined that greater environmental
benefits could result from this incentive to use low-VOC coatings
than will be gained by more stringent recordkeeping requirements
on use of these coatings.
Three commenters (IV-D-80, IV-D-83, IV-D-90) believe that
the reduced recordkeeping requirements for the 2.1 Ib/gal primer
should be extended to all compliant coatings. Commenter IV-D-90
stated that the reduced recordkeeping requirements should apply
to any facility using materials that have organic HAP and VOC
content below the limits in the proposed rule. The two other
commenters stated that if the EPA is willing to forego monthly
recordkeeping in the case of a low-VOC waterborne primer and
require only annual purchasing records, then the EPA should also
delete the recordkeeping requirements for all situations where
industry is converting to the use of low VOC or HAP containing
coatings; e.g., 2.9 Ib/gal for primers or 3.5 Ib/gal for
topcoats. These commenters believe that annual purchasing
records should be required when compliant coatings and solvents
are used. The commenters recommended that the EPA adopt a
provision which would allow the use of purchase records as the
only required form of recordkeeping.
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Commenter IV-D-90 recommended an amendment to §63.752(c)
which would state that only annual purchasing records and organic
HAP and VOC content records need to be maintained by any source
that elects to use primers or topcoats with a lower organic HAP
and VOC content level than the standard set forth in the proposed
rule.
Response: Proposed §63.752(c)(2) required monthly records
for primers with a HAP or VOC content greater than 250 g/1, while
§63.752(c)(3) required only annual purchase records for primers
with a HAP or VOC content less than or equal to 250 g/1. This
latter provision was intended to apply only to primers that were
not included in a daily-weighted averaging calculation. This has
been clarified in the final rule by inserting a new paragraph
(c)(4), which applies a separate recordkeeping requirement to
primers and topcoats complying with the HAP and VOC content
limits by averaging.
The EPA believes that monthly records for compliant
coatings, including primers with HAP/VOC contents above 250 g/1,
are appropriate.
13.7.3 Emissions Control Devices
Comment: Commenter IV-D-29 stated that semiannual reporting
for new particulate control devices is duplicative. The
commenter noted that control devices that require monitoring will
be required to report exceedances under the language of the rule.
Therefore, the commenter recommended that §63.753(c)(vii) be
deleted.
Response: The EPA agrees with this comment, and has deleted
proposed §63.753(c)(vii).
13.8 DEPAINTING OPERATIONS
Comment: Commenter IV-D-31 claimed that the proposed
procedures for verifying compliance with annual limits on HAP-
containing depainting solvents are insufficient. The commenter
recommended that the EPA require detailed records including the
date on which each gallon of depainting material was used, the
location on the aircraft, and the name of the aircraft. The
commenter stated that these records must be kept
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contemporaneously or monitoring compliance will practically be
impossible. The commenter noted that manufacturers remain free
to avoid this recordkeeping by simply keeping their zero emission
depainting system operational, or delaying depainting during
failures of the depainting equipment.
Response: The proposed rule, at §63.752(e), prescribed
detailed records to be kept on depainting operations, both for
chemical strippers and for non-chemical based (dry media)
depainting. These recordkeeping requirements are believed to be
sufficient, and facilities are not "free to avoid" keeping these
records.
Comment; Commenter IV-D-27 stated that the recordkeeping
requirements specified in proposed §63.752(e) (5), which relate to
the particulate control efficiency of each particulate filter,
and all test results, data, and calculations used in determining
the control efficiency, need to be revised to take into account
the commenter's recommendation that manufacturer's data be
acceptable for demonstrating compliance with the particulate
control efficiency requirement.
Response: These recordkeeping requirements have been
revised to reflect the changed requirements in §63.750(1), which
no longer requires the use of Method 5 in determining the control
efficiency of particulate filter systems.
Comment: Commenter IV-D-43 stated that most local air
districts have established procedures for reporting equipment
breakdown and obtaining a variance to operate in violation of the
rule requirements for the duration of the variance. The
commenter, therefore, recommended that any variances obtained
from the local districts be part of the recordkeeping format for
depainting operations.
Response: Variances obtained from local air control
districts cannot be made a part of the recordkeeping for
depainting operations under this NESHAP. The EPA wishes to make
application of this regulation consistent and equitable on a
national basis (as requested by the industry), which would become
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very difficult if the varying criteria of local districts were
formalized into the NESHAP requirements.
Comment: Commenter IV-D-27 stated that their limited "spot
stripping and decal removal" is on small wings, fins, and
stabilizers for missiles, and their past records show that on an
annual average basis, per aircraft, they will not use over 55
gallons per facility per year of organic HAP-containing chemical
strippers. For operations of this type, keeping chemical
stripper use records on a parts basis for hundreds of small parts
would provide no benefit. The commenter suggested that the EPA
provide a de minimis amount and allow facilities to provide total
stripper quantity used per year. This commenter recommended the
following revision to §63.750(k)(1) :
"(1) For each chemical stripper used for spot stripping and
decal removal, determine for each annual period the total
volume as applied using the procedure specified in paragraph
(d)(2) of this section. If the total volume applied is less
than 50 gallons per year per facility, skip 63.750(k)(2).
(2) Determine the total number of aircraft for which
depainting operations began during the annual period as
determined from company records."
Response: The EPA has not incorporated the commenter's
recommendation because parts are not covered by the standard. In
addition, if a facility only used the volume specified by the
commenter, the facility would not be classified as a major
source. Also, the information collected by the EPA indicates
that there are no special performance criteria for chemical
strippers that would necessitate that the EPA set de minimis
exemptions for low-volume special uses.
Comment: Three commenters (IV-D-27, IV-D-29, IV-D-35)
stated that the depainting operation parts and assembly tracking
requirement for chemical strippers (§63.752(e)) would not provide
any benefit. Two commenters (IV-D-29, IV-D-35) stated that each
airplane has 2,000,000 to 4,000,000 parts and that parts may be
removed from an aircraft at one location and then shipped to
another for repair. Each assembly may contain detailed parts,
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and individual listing of each such part would be overly
burdensome.
Commenter IV-D-29 also supported annual recordkeeping and
recommended the following revisions:
"§63.752(e)(1)(iii): Monthly Annual volumes of each
organic-HAP containing chemical stripper.
»
1163.752 (e) (2) For each model of aircraft depainted at the
facility, a listing of the parts,subassemblies,and
assemblies normally removed from the aircraft before
depainting."
Commenter IV-D-35 recommended the deletion of §63.752(e)(2).
Response: The language in the rule and preamble does not
require that the number of parts depainted per assembly be
recorded. For each model of aircraft depainted at the facility,
a listing of the parts, subassemblies, and assemblies normally
removed from the aircraft before depainting should be recorded.
The name, HAP content, and supporting documentation for each
chemical stripper must be recorded in addition to the monthly
volume of each organic HAP-containing chemical stripper used.
The EPA continues to believe that monthly records of organic
HAP-containing stripper are necessary to track a facility's
usage, and has retained this requirement in the final rule.
Comment: Two commenters (IV-D-29, IV-D-35) stated that
semiannual reporting requirements that are not monitoring
parameters or instances of non-compliance are unduly burdensome.
Commenter IV-D-29 recommended that §63.753(d) (1) (ii), (iii),
(iv), and (v) be deleted.
Both commenters objected to §63.753(d)(1)(viii), which
requires a list of new and discontinued aircraft models depainted
over the last 6 months and a list of the parts normally removed
for depainting. Commenter IV-D-35 stated that parts removed
from the aircraft may or may not be stripped with chemical HAP-
containing stripper. Commenter IV-D-29 noted that several
assemblies may be removed for depainting during rework, repair,
or out of sequence operations. Commenter IV-D-35 also pointed
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out that the definition of "new and discontinued aircraft models"
has not been adequately delineated. The commenter stated that
some models have only one aircraft and the repair cycle on that
aircraft is 4 to 6 years. The commenter noted that, although
these would not be considered new, they commonly would not have
received maintenance in the previous 6-month reporting period.
The commenter pointed out that as written, the rule would require
the reporting of the parts removed from unique aircraft during
each maintenance cycle. The commenter believes that the
documentation of chemical usage should be sufficient. Both
commenters recommended that §63.753(d)(1)(viii) be deleted from
the rule.
Commenter IV-D-35 also suggested that the annual statement
of compliance required for §63.753(d)(2)(ii) be deleted. The
commenter believes that this requirement is duplicative since
annual compliance reports are a requirement of the title V
permit.
Response: As discussed in a previous response (see Section
13.4), the EPA believes that the semiannual reporting period
suggested in the General Provisions is the appropriate period for
most reports required under the aerospace rule. Reports that are
less critical have a longer (i.e., annual) reporting interval.
The EPA's intention in §63.753(d)(1)(viii) is to require
facilities to maintain a master list of all models of aircraft
depainted at the facility and a list of the parts normally
removed from the aircraft for depainting. The EPA does not
intend for a facility to prepare more than one list per aircraft
type. If the facility depaints the same aircraft every reporting
period then the same list may be submitted for each report.
The EPA also believes that the semiannual compliance
statements are necessary. As previously discussed (see Section
13.1), reports prepared in response to the EPA's part 70 (title
V) program may in many cases be submitted to fulfill the
reporting requirements of this NESHAP.
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13.9 CHEMICAL MILLING MASKANT APPLICATION OPERATIONS
Comment: Commenter IV-D-15 stated that recordkeeping
already requires a lot of time. The commenter asked if chemical
milling maskant users will be required to keep duplicate records
for both the local AQMD and the EPA.
Response: The local AQMD may require certain records that
are similar to the NESHAP records. Where the information
fulfills the requirements of both local and Federal rules, a
single set of records may be deemed to be sufficient. This
compatibility decision will be made by the State/local agency.
Comment; Commenter IV-D-29 stated that semiannual reporting
of particular requirements in §63.753(e) for maskant operations
are unduly burdensome as they are not monitoring parameters or
instances of noncompliance. The commenter, therefore,
recommended that §63.753 (e) (iv) and (v) be deleted.
Response: The EPA believes that reporting the chemical
milling maskants and control devices used by a facility is not
unduly burdensome and provides the EPA with the information
necessary to monitor a facility's compliance. Therefore, these
two provisions have been retained.
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14.0 BASELINE/ENVIRONMENTAL IMPACT CALCULATIONS
14.1 CLEANING OPERATIONS
Comment: Commenter IV-D-22 stated that virtually none of
the new low vapor pressure solvents are listed as hazardous
wastes, and rag/solvent assemblies are not characteristic wastes
under RCRA since they will not likely have flashpoints above
140°F. Therefore, the commenter believes these wastes may be
disposed of in sanitary landfills because they do not need to be
managed as hazardous waste under the proposed rule.
Additionally, the commenter stated that since rags containing the
low vapor pressure solvents are not required to be placed in
sealed containers, the rags could be placed in dumpsters and the
solvent remaining on the rags would be emitted to the air before
they can be disposed of. The commenter stated that it is not
good public policy to force the industry into solvents that do
not require disposal as hazardous waste.
Response: The cleaning operations standard does not allow
facilities to place solvent-laden rags in open disposal areas
such as dumpsters. All rags that contain solvent must be stored
in closed containers to prevent the release of vapors to the
environment. The EPA has not forced the industry into using new
low vapor pressure solvents for cleaning. The vapor pressure
standards were set using data obtained from the aerospace
industry, and represent the present level of control by the best
performing 12 percent of the industry.
14.2 DEPAINTING OPERATIONS
14.2.1 Chemical Stripping
Commenj;: Commenter IV-D-78 stated that there are
significant cost reductions in waste treatment when a facility
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uses a non-HAP stripper instead of methylene chloride strippers.
The coitunenter suggested that the amount of waste that needs to be
hauled away for off-site treatment (incineration) or to landfills
is greatly reduced.
According to the commenter, almost all facilities with even
minimal treatment capabilities can treat the waste generated
through the use of non-HAP strippers. The commenter also stated
that the generation of large volumes of rinse water with trace
levels of methylene chloride, which must be disposed of off-site,
is eliminated.
The commenter suggested that the low volatility of the
solvents used in non-HAP strippers minimizes the amount of
stripper that evaporates during use or treatment. According to
the commenter, the low solubility of non-HAP strippers in water
simplifies the treatment process. The commenter claimed that the
nonhazardous nature of these solvents eliminates the need for
landfill or incineration of all but the stripped paint itself.
Commenter IV-D-46 stated that, based on their knowledge and
experience, the bulk of the solvent content in non-HAP strippers
is removed by the straining and/or clarifying stage before the
wastewater is actually treated. According to the commenter, the
small part that remains is essentially 100 percent removed during
the alum/polymer treatment that normally follows the
straining/clarifying stage, and any trace amounts that might
still be present are rapidly degraded by oxidation or
biodegradation. The commenter claimed that by the time the waste
reaches the aeration stage, there is no solvent portion
remaining.
According to commenter IV-D-5, strippers that do not contain
methylene chloride usually dissolve the paint, so the remaining
material is an integral mixture of the inorganic HAP and the used
remover which must all be disposed of as hazardous waste. The
commenter stated that the waste associated with the use of
methylene chloride strippers is confined to the paint chips only.
The commenter also stated that VOC emissions from non-HAP
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strippers may be as great as emissions from methylene chloride
removers since the non-HAP removers work so slowly.
Commenter IV-D-5 claimed that the statement from the Federal
Register. "Rework facilities that presently use a methylene
chloride-based paint stripper must dispose of 3,469 tons per year
of paint/solvent sludge created by depainting," is false and
shows one of the "obvious fallacies" of this study in that it
omits data from the depainting and refurbishing industry. The
commenter stated that methylene chloride-based paint strippers
are not disposed of as a sludge, but are flushed from the paint
chips and into the rinse water which can then be treated.
According to the commenter, the use of non-HAP removers requires
four or five applications of remover, whereas only two
applications are normally required for methylene chloride
removers. The commenter concluded by stating that this increases
water contamination and compounds the already difficult task of
having to clean non-HAP wastewater.
Response: Data collected from the industry indicate that
many facilities are using depainting methods that release no
organic HAP to the atmosphere. Facilities that use non-HAP
strippers were determined to be MACT since more than 12 percent
of the facilities, of which the EPA has knowledge, release no
organic HAP during their depainting operations. Additionally,
the EPA added other depainting operations to the standard after
the proposal date. Specifically, the standard has been revised
to allow the use of HAP-containing strippers with an 81 percent
control level for the emissions resulting from the use of these
products.
The EPA also has knowledge that both non-HAP and HAP-
containing strippers generate waste which is hauled off-site for
disposal. Based on the information collected by the EPA, both
types of chemical strippers generate a sludge of dissolved paint,
paint chips, and stripper which is collected in drums and
disposed of. Technologies exist for the treatment of wastewater
from both processes, but only one or two facilities in the
industry utilize this technology. The EPA believes that carbon
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adsorption is a viable control option for the air emissions
generated by HAP-containing strippers and has added carbon
adsorption as a control option.
Comment; Commenter IV-D-38 stated that the EPA's analysis
of non-HAP strippers assumes that significantly lower (by about
two-thirds) quantities of wastewater are generated than those
associated with the use of HAP strippers. The commenter believes
that this assumption is neither consistent with the data
submitted by Delta Air Lines, which forms the basis for the
Agency's consideration of non-HAP strippers, nor with data
submitted by the Paint Remover Manufacturers Association (PRMA).
Commenter IV-D-47 pointed out that, according to the EPA's
background material, use of non-HAP strippers will result in
increased solid waste generation of approximately 2,220 gal/yr
for a small plant and 6,610 gal/yr for a medium plant, which
constitutes a 47 percent increase in solid waste. The commenter
stated that while the EPA assumes that the contaminated solvent
sludge can be treated on-site, it is not clear from the
background materials that this practice is, in fact, possible.
The commenter also was not clear as to why there would be a
decrease in wastewater generation, as the EPA suggests, since use
of non-HAP strippers is followed by a water rinse, similar to
that used with DCM-based strippers.
Commenter IV-D-5 claimed that the statement in the standard,
"the decrease in wastewater nationwide is estimated to be 251
million gallons and 86 million gallons if all affected sources
use dry media blasting or chemical strippers that do not contain
organic HAP, respectively," is false. The commenter maintained
that current paint remover formulas that are non-methylene
chloride or non-HAP require an increase in water due to the
inability to include soap systems in the formulas that would
allow them to rinse as easily as methylene chloride water rinse
removers.
Response: The EPA has determined that the wastewater
generated by the use of media blasting, non-HAP strippers, and
HAP-containing strippers is approximately the same. The aircraft
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is rinsed after each of these operations. However, the Agency
has collected information that indicates that wastewater
generated by non-HAP strippers and plastic media blasting
operations can be treated on-site. Wastewater generated from
methylene chloride containing strippers must be disposed of in
order to prevent the escape of HAP since methylene chloride is
very volatile and is readily soluble in water.
Comment; Commenter IV-D-5 stated that the EPA's estimated
HAP emissions of 189,000 Mg/yr (208,000 tpy) is grossly in error
with the known amounts of methylene chloride used annually by the
industry.
Response: No specific data or suggestions for revision were
offered by the commenter. Therefore, the EPA believes that its
estimate of HAP emissions from depainting, based on collected
data, is accurate.
14.2.2 Media Blasting
Comment: Two commenters (IV-D-5, IV-D-38) stated that all
aircraft that are media blasted are detergent washed and rinsed
after blasting and the rinse water is hazardous due to
contamination from heavy metals. Commenter IV-D-38 claimed that
in light of considerable quantities of dust generated by the
media blasting process, it is very unlikely that the EPA is
correct in asserting that wastewater generation would be
eliminated with a switch to media blasting. The commenter stated
further that there is no reason to assume that media-blasted
aircraft would require less rinsing than aircraft stripped with a
HAP stripper.
Commenter IV-D-38 claimed that the use of media blasting
produces a six-fold or higher increase in the generation of solid
waste, compared to a depainting operation using a HAP stripper.
The commenter also remarked that the waste from blasting
operations is composed of spent media, paint, and other residues
that will typically include sufficient levels of metals to be
categorized as hazardous.
Commenter IV-D-47 stated that even if the data on media
blasting were applicable to commercial facilities, the EPA's
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evaluation projects that use of media blasting would result in an
increase in solid waste composed of spent blasting media and dry
paint chips of 13,280 tons per year on a nationwide basis. The
commenter claimed that this means that solid waste generation
would be increased 4.4 times over the amount generated by DCM-
based strippers. The commenter suggested that this figure may in
fact be an underestimate, because the EPA incorrectly assumed
that rework facilities using a DCM-based paint stripper currently
must dispose of "31,300 tons per year of paint/solvent sludge"
(NESHAP proposal background document, p. 1-8). The commenter
indicated that in practice, DCM-based stripping produces a much
lower volume of paint/solvent sludge. Additionally, the
commenter expects energy usage to increase by 51 million kWh/yr
if all facilities adopt media blasting as MACT.
Commenter IV-D-5 referenced the statement from the Federal
Register, "The increase in energy consumption involved in
operating dry media blast systems is estimated to be 51 million
kWh per year" and stated that the increased air pollution
including both organic and inorganic HAP from the electricity
generated must be included in any calculation. The commenter was
concerned about the air pollution associated with generating 51
million Kwh per year and stated that these data are needed to do
a valid comparison between the environmental impact of using
media blasting versus chemical depainting.
Response: The EPA collected extensive information from the
industry in order to determine the types of waste generated and
treated at aerospace facilities, and the docket contains this
information. Furthermore, the EPA does not endorse or require
that facilities use media blasting or any other particular method
to perform depainting operations; the final rule provides
flexibility in allowing several options including DCM use in
combination with control equipment.
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15.0 BASELINE/ECONOMIC IMPACT CALCULATIONS
15.1 CARBON ADSORPTION SYSTEM
Comment: Commenter IV-D-15 asked how the EPA derived the
$500 million estimate of the capital cost for carbon adsorbers
for chemical milling operations. The commenter stated that if
there are 20 facilities that do chemical milling and assuming
none of them has a carbon adsorber in place (according to the
commenter, 10 of them are presently using these systems, and the
most expensive system built to date cost $2.5 million, including
the enclosure and conveyor), then the total capital cost would
appear to be $50 million, not $500 million.
Commenter IV-D-19 objected to much of the technical content
contained in the August 25, 1993 EPA memorandum, "Cost Analysis
for Chemical Milling Maskant." Specifically, the commenter
expressed the following concerns:
l. The commenter objected to the cost basis used for the
added cost associated with carbon adsorbers. The
commenter stated that the actual added cost must
include both the carbon adsorber and its associate
enclosure, since the enclosure is required to operate
an adsorber in MACT mode. The commenter pointed out
that the enclosure must be heated and carefully sealed
to avoid emissions. The commenter stated that this was
omitted from the analysis, and therefore the capital
costs were underestimated.
2. The commenter stated that there is a problem with the
utilities cost estimate in Table 2 of the memo. The
commenter pointed out that in Table 2 the utilities are
estimated at $34,200 per year for operating a carbon
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adsorber, but in another memo the energy cost is
estimated to be 1,303,005 kWh per year. Using a
electricity cost of $0.05/kWh, the cost is calculated
to be $65,152 per year.
3. The commenter stated that the recovery credit of
$141,000 per year is suspect. According to the
commenter, reclaimed solvent (perchloroethylene) sells
for $2.00 per gallon, so the system must be producing
70,000 gallons of perchloroethylene, even for the small
plant, yet this cannot be if the plant only uses 12,000
gallons of maskant.
4. On page 5 of the memo, the commenter stated that the
waterborne maskant system being compared is a totally
irrelevant case. The commenter stated that the only
1.3 Ib HAP per gallon (less water) maskant that is
accepted on specifications by the industry is a single-
tank system, not a three-tank system, and that only one
oven is required, not two. According to the commenter,
these mistakes cause the capital costs for the
waterborne capital costs to be greatly exaggerated - -
instead of $220,400 for a medium plant, the cost that
should be used is $87,700 to reflect a single tank,
single oven arrangement.
5. On page 7 of the memo, the commenter claimed that a
mistake is made when volume solids in solution is used
to calculate volume solids dry. The commenter stated
that they have taken measurements that show for a
solvent based maskant (AC-828) the coverage is 25 ff
per gallon and for a waterborne maskant (CAX-200+) the
coverage is 37 ft2 per gallon.
Commenter IV-D-15 stated that they believe that the proposed
regulation assumes that the carbon from the adsorber units cannot
be recycled. The commenter provided a letter stating that it can
be reactivated and reused.
Response: The EPA's analysis indicates that only medium and
large, commercial and military OEM facilities use chemical
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milling maskants. The total number of facilities, based on the
information collected by the EPA, is 58 medium model plants and
13 large model plants.
The cost calculations performed for carbon adsorption
systems were performed in accordance with procedures specified in
the EPA's OAQPS cost manual. Using the procedure described in
the manual, the calculated total installed cost includes pumps,
condensers, and associated equipment. The method is widely
accepted and can be used to obtain a reasonably acceptable cost
estimate for an installed system. The EPA believes that the
derived figure is a good estimate.
The utilities calculation was incorrect in the August 25,
1993 memo. The calculation assumed that the facilities operate
24 hours per day, 365 days per year. Using actual data submitted
by McDonnell Douglas, which performs maskant operations 3,640
hours/year, the annual electricity usage should be 71,900 kWh per
year. At $0.05/kWh, the annual cost is $4,000/yr. When adding
the other sources of energy use, cooling water and steam, the
overall annual utilities cost should equal approximately
$27,900/yr.
Only McDonnell Douglas reported information stating that
perchloroethylene was sold back to the maskant vendor. Based on
the number of hours that this facility operates and their
reported data, the recovery credit should be $28,400/yr, not
$141,000 as previously reported.
Additionally, the EPA collected information that indicated
that the 1.3 Ib/gal HAP-containing waterborne maskant uses a
three-tank system, not a one-tank system as suggested by the
commenter.
The surface area coverage per gallon of maskant was derived
from manufacturer's specifications for solvent based and
waterborne maskant. Using the average of the data reported to
the EPA, the average was determined for each type of maskant.
The EPA is aware that activated carbon can be recycled.
Further, the EPA discovered an error in the calculated usage of
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carbon in the initial calculations. The carbon disposal costs
should have been $10,000 instead of $47,100.
Therefore, the total annual costs for a medium or large
facility should be approximately $169,000/yr. When multiplied by
the number of affected sources, 58 medium and 13 large plants,
the total annual investment is $11.98 million nationwide.
The total capital investment required per facility is
$383,000 for medium facilities and $411,000 for large facilities.
The nationwide capital investment should be approximately $27.56
million.
15.2 DEPAINTING OPERATIONS
Comment: Commenter IV-D-5 maintained that the following
comment from the proposal preamble in the Federal Register, is
false, "The use of chemical strippers that do not contain organic
HAP is essentially the same as the baseline solvent stripping
operation; therefore, no energy impact will result from their
use." The commenter stated that the most promising non-HAP
removers require 24 hours or longer dwell time as compared to 1
to 2 hours for methylene chloride removers. According to the
commenter, this is an increase in overhead and operating expenses
which must be added to the cost of compliance and the commenter
suggested that the "baseline energy impact must be multiplied by
12.
Response: Data collected by the EPA indicated that
methylene chloride stripping is used to strip planes at rates of
30 minutes to 40 hours per plane. For non-HAP strippers, the
rate was reported from 2 hours per plane to 160 hours per plane.
Therefore, the time required for stripping appears to be a
function of the facility's operational procedures.
Comment: Commenter IV-D-5 stated that the $0.3 million
annual cost estimate for blast depainting operations averages to
an annual cost of $1,045 per facility and is grossly in error.
Response: The MACT cost analysis for aircraft depainting
lists the annual cost of $168,400/yr for small model plants,
$266,130/yr for medium model plants, and $1,149,680/yr for large
model plants to implement plastic media blasting (II-B-47). Data
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collected by the EPA indicate that approximately 5 percent of all
aerospace facilities perform depainting operations. Therefore,
using 5 percent of the small, medium, and large model plants,
there are 27 small plants, 73 medium plants, and 5 large plants
performing depainting operations. The total nationwide annual
cost associated with MACT implementation for all affected rework
facilities is $29.7 million per year.
Comment: Commenter IV-D-5 stated that the baseline cost for
methylene chloride depainting was taken from a military rework
facility, which is not representative of the depainting and
refurbishing industry for two reasons. First, the stripper being
used is a military specified remover which is not as efficient as
modern strippers and may contain both organic and inorganic HAP.
Secondly, labor costs and overhead of the American military are
not representative of American industry. The commenter claimed
that media blasting processes that are currently used within the
depainting and refurbishing industry result in 5 to 10 times the
current labor costs of methylene chloride depainting.
The commenter stated that the proposed standard
misrepresents the cost of painting aircraft with the assumption
that since fewer coats of paint are applied with high volume low
pressure (HVLP) spraying, the labor costs decrease in proportion.
According to the commenter, this is a false assumption since
travel time with an HVLP spray gun must be slowed to allow for
slower film build. The commenter stated that the labor costs
with HVLP and conventional spray guns are about the same.
Response: The EPA used data collected from the industry to
develop the MACT standards for the NESHAP and to develop the
economic cost analysis. The EPA believes that the data reported
by the industry were accurate and that the information represents
valid and currently used techniques and costs throughout the
industry.
Comment: Commenter IV-D-35 suggested that the inorganic HAP
emissions from water, flashlamp, and laser stripping technologies
are realistically orders of magnitude lower than the emissions
from dry media blasting. According to the commenter, by using
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the same analysis chosen for a plastic media blasting (PMB)
facility, adding particulate filtration controls to a hangar
where these alternative technologies are used for stripping would
cost on the order of $4 million to control less then 0.002 ton
per year, resulting in an annualized cost of $790,000 per year,
or $395 million per ton of emissions controlled.
As an example, the commenter provided the following
scenario:
1. If a PMB operation produced 4.25 Ib/hour of total
emissions, operated for 15 blast hours, 330 days per
year, the savings in emissions between 99 percent and
84 percent would be approximately 0.13 ton/year.
2. The additional filtration (84 to 99 percent) would cost
over $900,000 for capital improvements for adding a
HEPA filter system and $129,000/yr in additional O&M
costs, for an annualized cost of $235,000 per year (20
year, 10 percent amortization on capital + O&M costs).
3. Thus, controlling the additional 0.13 ton per year of
inorganic HAP emissions would cost over $2.6 million
per ton.
The commenter also provided the results of a commissioned
study that investigated the estimated cost impact to the Air
Force. The commenter's study indicated that the Air Force can
expect $10 million in capital costs and an additional annual O&M
cost of $1.8 million/yr for adding HEPA filtration systems to Air
Force depaint hangars. The commenter estimated incremental
control cost at $2.6 million/ton of HAP reduction. According to
the commenter, if depainting operations cannot achieve 99 percent
at a reasonable cost, the Military may be forced to convert
current PMB, medium pressure water, high pressure water, and
Flashjet processes to environmentally compliant chemical
strippers. The commenter estimated that the Navy's capital costs
would be $1.3 million with an additional $0.5 million/yr for
O&M. The commenter stated that no upgrade cost were projected
for the Army, since all booths would be new. The commenter
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pointed out that the total DoD capital cost related to the 99
percent control efficiency requirement would be $11 million.
The commenter concluded by stating that the 99 percent
control efficiency requirement for controlling inorganic HAP
emissions from depainting will lead to significant costs for
facility improvements without providing documented environmental
benefits.
Response: The EPA has eliminated the 99 percent control
efficiency in the final rule, and has imposed a set of workplace
practices for facilities using media blasting depainting
techniques and methods. In addition, the final rule specifies
that particulate filters are required only for dry media blasting
operations. The EPA has also implemented a new source MACT
requiring the use of HEPA or three-stage dry filters for coating
application operations involving chromium or cadmium emissions.
No control efficiencies are specified in the final rule because
no data were available that utilized the recommended test
methods.
Comment: Commenter IV-D-78 noted that some commenters have
claimed that non-HAP chemical strippers are so much more
expensive than conventional methylene chloride-based chemical
strippers that it is not economically viable to switch to this
new technology. The commenter stated that this is not the case
and, in fact, a cost savings is realized. The commenter stated
that although the unit cost of these products is somewhat higher,
the overall cost of the depainting operation has been shown to be
reduced due to savings in material consumption (30-60 percent),
man-hours (25-50 percent), and waste treatment costs (40-90
percent).
Response: The EPA's cost analysis of the MACT technologies
indicated that facilities that switch to non-HAP strippers should
have a decrease in their overall operating expenses.
Comment: Commenter IV-D-38 noted that the large commercial
airlines operate an estimated 4,000 aircraft, the majority of
which are currently depainted using HAP-containing (i.e.,
methylene chloride) strippers and that an additional 2,000
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planes, operated by regional (commuter) airlines, and several
thousand private aircraft also are maintained with HAP-containing
strippers. The commenter also noted that many military aircraft
also are stripped with HAP-based products. The commenter
suggested that according to the data submitted to the record,
depainting of these vehicles occurs in a significant percentage
(greater than the Agency's 5 percent estimate) of the 2,000
commercial and military facilities that perform maintenance of
aircraft. As a result, the commenter believes that the economic
impact of the aerospace NESHAP would be significant.
The commenter noted that the EPA's analysis of the cost of
complying with the proposed depainting standard is based on the
use of plastic media blasting. The commenter claimed that
available evidence suggested that the more expensive process of
wheat starch blasting is far more likely to be viewed as
acceptable over time. The commenter believes that the Agency's
economic analysis, therefore, likely underestimates the cost of
compliance for military facilities by a considerable margin.
The commenter stated that, despite its use of a conservative
estimate of the cost of media blasting, the EPA recognizes that
the cost of media blasting would be prohibitive for most
facilities, stating that "due to the high capital cost of blast
depainting equipment, very few facilities are expected to use
this option other than those that already have it." The
commenter suggested that this is a rather curious statement in
light of the fact that media blasting would be the only
acceptable depainting alternative for military operations
currently using HAP strippers.
Response: The final rule allows facilities to use many
different methods and techniques for depainting. The EPA did not
use media blasting as the basis for calculation of the cost
impacts. Methylene chloride-containing strippers were used as
the basis of calculation since many facilities currently use this
type of stripping operation.
Additionally, the commenter did not offer any statistics or
supporting data in order for the EPA to evaluate whether the 5
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percent estimate should be revised. Therefore, the 5 percent
estimate is considered to be valid by the Agency.
Comment: Commenter IV-D-47 stated that the projected
economic impacts of the depainting provisions are one reason that
the proposed MACT standard must be revised. The commenter noted
that according to the EPA's economic analysis, if all aerospace
rework facilities were to install media blasting equipment, a
nationwide capital cost of $2.8 billion is expected with an
additional capital cost of $54.5 million to install equipment to
control the inorganic HAP emissions from media blasting systems.
The commenter pointed out that even these astronomical
figures may be an underestimate, because the EPA simply assumed,
without any evidence to support such an assumption, that only 5
percent of small and medium rework facilities perform outer
surface depainting of aerospace vehicles.
Commenter IV-D-5 stated that the number of small and medium
rework facilities performing depainting is actually 40 to 50
percent, instead of 5 percent as assumed. This commenter pointed
out that the NESHAP preliminary draft BID, Appendix A,
Development of Environmental Impacts, shows a cost of $250,000
for a facility to depaint small aircraft and $700,000 for medium
to large aircraft, which, the commenter states, conflicts with
the $61 million capital cost given for implementing dry media
blasting equipment. The commenter stated that the $61 million
figure is in error and grossly underestimates the capital costs
involved.
Commenter IV-D-47 suggested that, since the EPA's cost
analysis is based only on plastic media blasting, it does not
take into account the additional cost of specialized equipment
required for certain blasting technologies such as wheat starch
blasting, which may require a dedicated facility or a blast and
vacuum unit. The commenter noted that the EPA recognized that
the costs of media blasting would be prohibitive for most
facilities, stating that, "due to the high capital cost of blast
depainting equipment, very few facilities are expected to use
this option other than those that already have it." Yet, the
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commenter pointed out, the EPA still considered media blasting to
be an appropriate MACT standard.
The commenter claimed that this leaves a number of
facilities, particularly smaller ones, with only one option for
MACT compliance: non-HAP chemical strippers. The commenter
pointed out that the EPA's calculation that the use of non-HAP
strippers would result in a net savings of $38.8 million if all
affected sources used them, is based on data from only one
commercial facility that uses non-HAP strippers. The commenter
claimed that this limited information is clearly insufficient to
perform an adequate cost analysis. Additionally, the commenter
claimed that the EPA's analysis failed to take into account the
greater amount of time necessary to strip with non-organic HAP
chemical strippers and the corresponding increase in labor and
other costs, despite ample evidence in the record to that effect.
Two commenters (IV-D-5, IV-D-47) stated that, while the
EPA's evaluation recognized the greater cost and level of
consumption associated with non-HAP strippers, it assumed that
these costs were offset by reduced disposal costs for non-HAP
strippers. The commenters suggested that the anticipated
reduction in costs was based on the EPA's assumption that the
large amount of non-HAP solvent sludge could be treated on-site.
The commenters claimed that it is not clear from the record,
however, that this practice would be feasible at all or even most
facilities. Commenter IV-D-5 stated that the non-HAP strippers
contain solvents that result in higher treatment cost and result
in an increased annual cost. Commenter IV-D-5 also stated that
the cost to media blast an aircraft in the private sector is not
"minimal," but is 7 to 8 times the cost to depaint with methylene
chloride removers. The commenter also stated that many
manufacturers of aircraft limit each aircraft to only one media
blasting depainting per lifetime, which deflates the value of the
aircraft and limits its useful life. The commenter pointed out
that aircraft replacement costs due to the proposed standards
have been omitted from the economic impact analysis.
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In conclusion, commenter IV-D-47 stated that the prohibitive
cost of media blasting will have the effect of forcing many
commercial companies into trying non-HAP strippers if the
proposed standard is adopted. The commenter believes that this
will result in companies searching for non-HAP strippers that can
strip as effectively and quickly as DCM-based strippers, at an
increased economic cost to the company. The commenter suggested
that the health and environmental disadvantages associated with
increased emissions of chemicals may well prove to be much more
hazardous than DCM.
Response: The $61 million capital cost given for
implementing dry media blasting equipment is based on 5 percent
of the small and medium rework facilities and all of the large
rework facilities performing media blasting. The EPA is required
to determine the MACT floor based on the information available.
Since the information obtained utilized data from plastic media
blasting, the EPA believes it was correct in using this
information for its analysis.
The cost analysis for aircraft depainting indicates that
plastic media blasting is not 7 to 8 times the cost of methylene
chloride strippers.
The manufacturers of aircraft do not determine whether
rework facilities use media blasting or chemical stripping. All
facilities must have depainting procedures approved by the FAA to
insure airworthiness.
Comment: Commenter IV-D-5 maintained that the statement,
"Selection of chemical strippers that do not contain organic HAP
by all affected sources instead of dry media blasting would
decrease the total nationwide capital investment by approximately
10 percent," is false. The commenter stated that a facility's
size would have to be increased for both the use of non-HAP
removers and media blasting if the current workload capability is
to be maintained. The commenter added that this is due to a
reduction in the number of aircraft refurbished per hour.
Response: The EPA is required to use, and has used, the
information collected from the industry. The information was
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used to develop economic and environmental impacts based on the
various technologies in use.
15.3 PRIMER AND TOPCOAT APPLICATION OPERATIONS
Comment: Commenter IV-D-29 indicated that the costs of
research and development for identifying compliant topcoats and
primers do not appear to have been considered. According to the
commenter's experience, the assumed cost of $23 per gallon for
compliant paints appears too low. The commenter claimed that the
costs of obtaining low-VOC materials are at least 65 percent
greater than conventional materials (even at high volume usage
prices), while 75 percent greater is common for topcoats and 100
percent increases are common for primers.
Response: The EPA believes that the manufacturers absorb
research and development costs and include these costs in the
prices of their coatings. Extensive data were collected by the
EPA which indicated that the prices and market analysis presented
in the preamble are correct. The commenter did not provide any
data or specific information to substantiate their conjecture;
therefore, the EPA will continue to use the cost estimates for
these coatings in its revised impact analysis for the final rule.
Comment: Commenter IV-D-48 stated that they replaced the
high-VOC coatings they had been using with low-VOC coatings on
January 1, 1991, as required under its ARACT. Initially, the
commenter noticed that the costs of the low-VOC coatings were
appreciably more than the coatings that they had previously been
using. The commenter attributed the cost increase to the
increased fraction of resins and pigments and the reduced amount
of solvents in the coatings. In general, the commenter noted
that there was approximately a 20-50 percent increase in the cost
to purchase the low-VOC coatings; however, it was anticipated
that the coatings would cover more area due to the thicker
consistency from less solvents being used in the formulation of
the low-VOC coatings. The commenter pointed out that the cost of
productivity should be another potential concern for prospective
users of low-VOC coatings because there is a longer cycle for the
entire process of application, drying, and curing. The commenter
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suggested that, typically, a facility can anticipate between 1 to
3 additional days depending on weather conditions, familiarity of
the new low VOC product, etc. The commenter stated that they
were in a growth phase in 1991, making it impossible to
accurately determine the actual cost impact attributable to the
purchases of the low-VOC coatings.
Response: The EPA encourages the industry to submit
information for the sources regulated by the rule. However, the
information noted above is based on one particular commenter's
experience and may or may not represent market conditions and
operations in every sector of the industry.
Comment: Commenter IV-D-50 stated that they cannot meet the
HAP and VOC limitations proposed for primers and topcoats without
the installation of costly controls. The commenter pointed out
that they rework aircraft components in their repair division
facility and do not have control over the painting system used
during the rework processes because they must follow the system
specified by the customer. Therefore, the commenter suggested
that even if lower VOC/HAP primers and topcoats are available,
they do not have the freedom to use them.
The commenter maintained that the customer-specified
coatings, in many instances, match the OEM specifications used on
the original aircraft. According to the commenter, this is due
to the fact that the FAA requires rework to be performed (1) as
specified by the OEM, (2) as specified in engineering
documentation published by the airline, or (3) by a process that
has been approved by the FAA. The commenter stated that their
experience indicates that FAA approval of procedures that are
different than that specified by the OEM is difficult to obtain,
especially in the short timeframe the airlines typically require
for the repair of their aircraft components. The commenter also
indicated that airlines are reluctant to approve coating systems
that are different than those used by the OEM. Therefore, the
commenter is bound by the OEM specifications of the original
aircraft on most of the rework jobs.
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The commenter stated that they have worked extensively with
the OEMs to locate lower VOC coating substitutes, with no
success. The commenter claimed that, for the last 5 years, they
have been told lower VOC coatings are "in the works;" however,
the coatings used in their rework operations, based mainly on OEM
specifications, have not decreased in VOC content. The commenter
pointed out that this is especially true in the area of topcoats.
The commenter claimed that, if the aerospace NESHAP is
adopted as proposed, they will be required to install very
expensive controls to continue in their repair business. As a
result, the commenter believes that the EPA's economic model of
the impact of the proposed rules is severely flawed.
Response: The EPA understands that many rework facilities
are required by their customers to follow the OEM specifications.
The customers request that the rework facility follow OEM
specifications so that the owner of the aircraft can maintain the
warranty on the aircraft. The FAA doesn't mandate that rework
facilities follow OEM specifications for coating operations. The
EPA also expects many of the OEM specifications will be modified
with the implementation of the NESHAP.
The information contained in the rulemaking docket indicates
that many facilities are performing at the VOC and HAP content
limits specified in the final rule. The information collected by
the EPA indicated that 12 percent of the facilities were meeting
the required VOC/HAP content levels without the installation of
additional control devices. Installing control devices to
control organic HAP and VOC emissions is a compliance option when
a facility chooses to use coatings with VOC/HAP contents higher
than the levels specified in the rule.
Comment: Commenter IV-D-35 noted that the Air Force
recently surveyed 32 bases and the study revealed that 16 had
converted to HVLP and several others were using some HVLP in
painting activities. The commenter stated that HVLP equipment is
very painter dependent. When coupled with low-VOC paint, the
commenter suggested that a painter who normally uses conventional
spray equipment may actually apply more paint, instead of less,
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using HVLP. The commenter stated that training employees in the
use of HVLP increases costs.
The commenter noted that a decrease in paint usage has not
been observed from conventional spray. Therefore, the commenter
sees no benefit in the EPA mandating that the aerospace industry
switch to HVLP from conventional spray.
The commenter suggested that the Military's experience
indicates that there is a significant difference in the cost per
labor hour per gallon of coating applied. According to the
commenter, while this cost may come down over time as the
technology matures, in today's market HVLP represents no cost
savings and only minor emission savings. The commenter suggested
that the labor-hours for high solids paint use may increase due
to required greater attention to the details of the application.
The commenter stated that painters must work slower with HVLP and
additional cleaning and rework are sometimes required, increasing
labor costs. The commenter also stated that the labor costs
associated with the act of simply spraying the paint are only a
small portion of the overall labor cost associated with painting
a part. The commenter claimed that a 50 percent increase in
drying time is common for low-VOC coatings applied with HVLP,
which in turn leads to more labor cost and inventory expense.
Response: The information contained in the docket indicates
that HVLP actually leads to application of less paint than
conventional spray painting because the coatings formulated for
HVLP have less volatile solvent than the coatings formulated for
conventional spray application.
Comment: Commenter IV-D-95 stated that the cost of
installing a carbon adsorption process in their paint and
stripping operation is estimated at $7.5 million. The commenter
pointed out that they can process approximately 60 aircraft per
year. The commenter stated that the estimated price of
installing carbon adsorption (plus operating expenses),
depreciated over 7 to 10 years, will increase the price to paint
an average aircraft by approximately $18,500, which equates to a
65 percent increase. The commenter stated that the addition of
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catalytic incineration would increase the price increase to over
100 percent.
Response: The EPA does not require the use of carbon
adsorption control devices for compliant coatings and strippers.
Facilities have the option of using compliant coatings and
strippers without a control device.
15.4 CLEANING OPERATIONS
Comment: Commenter IV-D-50 stated that the proposed
requirements for spray gun cleaning operations are unduly
burdensome on companies that spray many different types of small
parts. The commenter claimed that the gun cleaning requirements
are much more onerous on them (a rework facility) than a large
OEM, since they have to change coatings more frequently than the
large OEM. The commenter, therefore, believes the requirements
have a greater impact on companies that are rework facilities and
than on OEM's. The commenter claimed that this is particularly
true if disassembly and vat cleaning are used as a means to
comply with the gun cleaning requirements.
Response: The EPA is unsure about what alternatives the
commenter would recommend. Spray guns do not have to be cleaned
each time a different coating is applied. The operator may apply
as many coatings as they wish as long as each time the gun is
cleaned, the cleaning operation follows the provisions set out in
the standard. The standards do not require disassembly each time
the gun is cleaned; there are several cleaning methods available.
The EPA does not believe that the standards will impose undue
hardship on the industry.
Comment: Commenter IV-D-29 believes that the EPA's cost
estimates for compliance with the proposed cleaning operation
standards may be based on incomplete information. The commenter
understands that the EPA's cost estimates were based on a single
case of one solvent substitution conducted at one company, which,
according to the commenter, would not adequately represent the
industry. The commenter stated that in addition, the baseline
cost range for typical existing solvents listed by the EPA seems
high. The commenter noted that the typical cost for MEK is less
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than $2.00/gal and that the listed costs for low vapor pressure
solvents seem low. The commenter claimed that some low vapor
pressure materials cost $20 to $30/gal. The commenter believes
that disposal costs associated with this section may also not be
representative. The commenter claimed that a large commercial
OEM's disposal cost can be three times greater than the costs
listed in the proposed rule. The commenter suggested that the
use of low vapor pressure solvents may actually increase the
quantity of rags used, increasing waste and the costs of
disposal.
Response: The EPA believes that there is ample information
in the docket to support the economic impact analysis for the
implementation of the MACT standard for cleaning operations.
15.5 RECORDKEEPING AND REPORTING
Comment: Commenter IV-D-35 pointed out that the Air Force
estimated the cost of compliance with the aerospace NESHAP from a
recordkeeping and reporting perspective at $81 million annually.
Commenter IV-D-35 maintained that the recordkeeping and
reporting represents the predominant portion of the anticipated
annual environmental compliance requirement. In order to assist
the EPA in targeting areas of recordkeeping and reporting
requirements that might be reduced, the commenter provided a
distribution of activities that fall under the requirement. The
manpower requirements for each activity were listed in units of
full-time equivalents (FTE) projected on the basis of the
facility's size. The commenter provided the following list of
activities with the manpower requirements included:
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Recordlceeping and Reporting
Activities
1. Compliance Audit
2 . Tracking
3. Pharmacy: Tracking and
Dispensing
4 . Usage Tracking at Shop
Level
5 . Environmental Management
Reporting
6 . Shop Reporting
7 . Waste Tracking
8. Testing: Coordination
and Monitoring
Total Full Time Equivalents
Facilities
Small
0.25
0.25
0.5
1.5
0.10
0.10
0.05
0.25
3
Medium
0.25
0.25
0.5
3
0.2
0.2
0.1
0.5
5
Large
1
1
1
6
0.7
1.0
0.3
1
12
Average
Percent
7.2
7.2
11.7
53.4
4.4
5.1
2.1
8.9
100
The commenter pointed out that nearly half the effort is spent
tracking materials at the shop level. The commenter offered the
following suggestions to reduce the resource requirements:
1. Place greater reliance on the use of manufacturer and
supplier information, minimize duplicate compliance
certification testing. This would minimize activity #8
and #4 requirements.
• Maximized use of readily available MSDS
information to demonstrate compliance for HAP and
VOC content. This would minimize activity #8 and
#5 requirements.
2. Eliminate duplicate waste tracking requirements. This
would minimize or eliminate activity #7 requirements
and would minimize activity #4 and #2 requirements.
3. Revise regulations to allow use of central issue point
(Pharmacy) information to demonstrate compliance and
usage rates. This information would tend to
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overestimate usage rate, providing a conservative
margin of safety. This would slightly increase
activity #3 requirements, while minimizing activity #4
requirements.
• In turn, this would minimize the requirements for
usage tracking within the shop. This area alone
consumes nearly 50 percent of the FTE requirement.
This would greatly minimize activity #4
requirements.
• Maximize use of the Pharmacy data versus the need
for process- or source-specific information. This
would minimize activity #2, #4, #5, #6
requirements.
• Use purchase records to maximum extent. This
would minimize activity #8 and #1 requirements.
Extend the averaging times allowed for compliance
demonstration. This minimizes usage tracking and EM
reporting workloads. This would minimize activity #2,
#4, and #6 requirements.
Minimize the number and frequency of reports required
by the facility to the EPA or regulators. This would
minimize activity #5 and #6 requirements.
• Reduce Environmental Management requirements.
This would minimize activity #5 requirements.
• Reduce shop level usage tracking. This would
minimize activity #4 requirements.
The EPA could conduct widespread aerospace NESHAP
worker training (Workshops) nationally on site/in-
plant.
• Increase compliance awareness and expand knowledge
of the aerospace workforce regarding compliance
requirements. This would minimize activity #1
requirements.
• Assist upon request in instituting program
regarding required housekeeping measures and
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pollution prevention. This would minimize
activity #1, #4, #7 and #8 requirements.
• Increase the effectiveness of industry's internal
compliance auditing programs to reduce the
occurrence of violations. This would minimize
activity #5 and #4 requirements.
• Foster overall compliance and speed the
implementation in the workplace while minimizing
the cost burden of regulation. This would
minimize activity #5 requirements.
The commenter stated that intensive recordkeeping and
reporting will unnecessarily burden DoD installations. The
commenter claimed that the recordkeeping will require an enormous
increase in the manpower requirements dedicated to compliance
activities at the central issue point (Pharmacy), in the shop, in
the field, and in the environmental management offices at each
installation. The commenter estimated that the annual DoD O&M
compliance requirement for recordkeeping and reporting to
accomplish the above will exceed $142 million if the rule remains
unchanged. Recordkeeping requirements account for 55 percent of
the DoD's total O&M compliance ($256 million) for the aerospace
NESHAP. The commenter noted that additional costs would be
incurred if the rule were to apply to non-major aerospace sources
located at any major source.
Response: For facilities choosing to use compliant
materials, the recordkeeping and reporting requirements are the
minimum amount necessary in order to determine compliance. When
non-compliant coatings, strippers, and maskants are used,
stricter recordkeeping requirements are necessary. Over 25
percent of the aerospace industry is located in California.
Facilities in California are typically located in nonattainment
areas and must meet emission limits that are more stringent than
any other area of the country. Because these facilities have
already been required to meet the limits set by the State Agency,
the EPA does not anticipate that very many of these facilities
will have to alter their operations in any significant way.
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Several of the Military's affected facilities are also located in
California. In order to provide facilities located in attainment
areas with additional flexibility, the EPA has changed the daily
recordkeeping requirement to monthly or as determined by the
permitting authority. This requirement also gives State and
local air quality agencies the authority to implement time
periods necessary to ensure the public's safety.
15.6 GENERAL COMMENTS
Comment: Commenter IV-D-35 noted that the EPA is required
to conduct a cost analysis to determine the cost to the aerospace
industry of complying with the proposed NESHAP, and that the EPA
published this study in the background document for the Aerospace
NESHAP. After a review of this document, the commenter believes
that the costs presented in the background information are
greatly understated.
The commenter pointed out that in order to sufficiently plan
future funding requirements, in July 1994 the Air Force
commissioned a cost impact study of the proposed EPA aerospace
NESHAP. The cost impact study initially focused on anticipated
Air Force-wide costs and was later expanded to project Navy and
Army costs. The commenter's study provided the anticipated total
costs for DoD in the event the regulation is not modified to
include the various exemptions, exclusions, or other
modifications proposed by the commenter.
The commenter's study addressed the following major areas of
the regulation: General, Cleaning Operations, Primer and Topcoat
Application Operations, Depainting Operations, Chemical Milling
Maskants Application Operations, Handling and Storage of Waste,
Compliance Dates and Determinations (if applicable), Performing
Test Methods/Procedures, Monitoring Requirements, and
Recordkeeping and Reporting Requirements. Additionally, the
commenter evaluated these areas with respect to the following
major issues: Maintenance Painting; Mechanical Sanding;
Manufacturer's and Supplier's Specifications and Information;
Touch-up and Repair; Inorganic HAP Filter Efficiency; Emissions
Averaging/Emission Credits for Over Control; Flexible Primer;
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Testing, Recordkeeping & Reporting; Implementing Depainting
Options; Military Construction (MILCON) Funding Requirements; and
Total Costs.
The commenter stated that impacts on the DoD are illustrated
by the Air Force cost study. The commenter pointed out that this
study describes the applicability of the NESHAP to Air Force
installations and describes the cost analysis methods used to
develop the model facilities (large, medium, and small) employed
in the study. According to the commenter, the total projected
capital cost for the Air Force alone would be in excess of $721
million for 140 installations, with annualized costs greater than
$236 million per year. The commenter noted that costs will be
incurred for new construction, and for modification or upgrading
of existing facilities. In contrast, the commenter pointed out
that the EPA estimated annualized cost savings of $18 million per
year for the entire Military.
In particular, the commenter noted that the control of
inorganic HAP drives the majority of the Air Force's capital
costs ($606 million, or 84.1 percent) and approximately 39
percent of the annual operations and maintenance (O&M) costs.
The commenter stated that control of organic emissions drives the
flexible primer and the depainting issues, accounting for $67.7
million and 9.4 percent of the total capital requirements.
The commenter stated that the total Air Force annual O&M
costs for sustained compliance activities
(monitoring/recordkeeping and reporting) associated with the
major issues identified in Table 1 account for $152 million.
Recordkeeping associated with the manufacturer's specification
and waste tracking accounted for $83 million or 54.7 percent of
the annual projected O&M issues alone requirement. Additionally,
the commenter believes the proposed aerospace rule would
necessitate expensive changes to existing technical orders. The
commenter stated that this effort has been estimated at $40
million across the Air Force. In contrast, the commenter pointed
out that the EPA estimated the nationwide cost of recordkeeping
at $36.7 million for the entire aerospace industry. The
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commenter noted that an examination of the EPA's background
information document (EPA-453/R-94-036a) indicated that in Table
9-19 the cost for control of inorganics has not been included,
but estimates that such costs would be "quite small." In
contrast, the commenter pointed out that the Air Force Cost
Impact Study projected the cost of control for inorganics at $606
million in capital costs. The commenter concluded that the study
indicates that the EPA has significantly underestimated the cost
to comply with the proposed rule.
By extrapolating the costs, the commenter determined that
DoD's total capital costs for 278 installations was
conservatively estimated at $1.2 billion. The associated annual
operations and maintenance cost for environmental compliance was
estimated at $256 million and the annualized costs were
conservatively estimated at $398 million per year. This analysis
did not include cost impacts on non-major aerospace sources. The
commenter noted that if the EPA elects to include non-major
sources under the final rule, then additional costs would be
incurred.
The commenter estimated that, for the DoD, the combined
inorganic HAP emissions from mechanical sanding, maintenance
painting, and touch-up and repair painting is approximately 3.4
tons per year, of which about 2 tons per year are from mechanical
sanding. The 3.4 tons per year, according to the commenter,
represents 1.2.percent of the industry-wide inorganic HAP
emissions from painting and depainting based on data in the BID.
The commenter stated that controlling the 3.4 tons of inorganic
HAP per year would require DoD to modify or build over 300
hangars and booths at a projected capital cost of $881 million
and annual O&M cost of $92 million. Based on a 20 year, 10
percent amortization, the annualized cost would be $196 million
per year. Therefore, the commenter estimated that the cost of
controlling 3.4 tons/year of inorganic HAP is approximately $58
million/ton. The commenter pointed out that cost of control for
a typical depot operation would be $107 million/ton (based on
total inorganic HAP emissions of 0.04 ton per year) and for a
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small fighter base, the cost would be $8 million/ton of inorganic
HAP emissions.
For the three operations listed above, DoD estimated that
350 buildings will require modification or replacement at a cost
of $881 million. According to the commenter, due to the long
time lag to upgrade this number of buildings (10-15 years), there
would be a significant amount of field corrosion repair work
delayed until depot maintenance could be scheduled, and then
delays in accomplishing depot maintenance. The commenter
believes this would affect both airworthiness and mission
reliability and increase long term corrosion repair costs.
The commenter stated that additional costs for controls due
to the lack of a flexible and workable emission averaging scheme
are also not fully included. The commenter believes that the
Aerospace NESHAP has the potential to have a several billion
dollar impact on the DoD. The commenter believes that several of
the proposed requirements identified in the EPA aerospace rule
are excessive for the limited environmental benefit received and
that, if unchanged, these requirements would severely burden the
military and industry alike. The commenter stated that
restrictions on DoD's operations that will result from imposition
of this rule compromise the military's ability to fulfill its
critical national defense role. The commenter claimed that full
funding to comply with the emission control requirements of the
NESHAP at unit-level maintenance areas may not be feasible (see
compliance cost estimates), and the services may subsequently be
forced to restrict some essential basic maintenance, now being
performed at the unit-level, to central locations. Moreover, the
commenter suggested that it may not be feasible to fund
compliance at all DoD intermediate maintenance facilities,
thereby reducing the number of centralized support facilities and
increasing the distance that some aviation units would have to
travel for routine maintenance and repairs. According to the
commenter, having to ferry aircraft to central locations for
minor maintenance and repairs could adversely affect operational
readiness by significantly reducing the time that aircraft and
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flight personnel are available to support military missions
including training. Additionally, the corranenter maintained that
the increased air time to reach central maintenance facilities
and the inability of unit personnel to perform some types of
basic maintenance and repairs at their home base may adversely
affect safety.
The commenter suggested that, based upon the projected total
DoD costs, it appears the EPA has significantly underestimated
the cost to implement the NESHAP. The commenter recommends that
the EPA reexamine the projected impact costs to industry
associated with compliance. The commenter stated that the Air
Force cost study should be used as a starting point to develop
realistic costs. The commenter pointed out that their
recommendation is consistent with Executive Order (E.O.) 12291
(46 FR 13193), section 2(a) which mandates that Administrative
decisions shall be based on adequate information concerning the
need for the consequences of the proposed action. The commenter
also recommends that an effort be made to strip the regulation of
excess burdens to source owners and operators and to ensure
reasonable benefit for the compliance investment required of the
aerospace industry. The commenter stated that the recommendation
should take into consideration the least net cost to society of
the alternative chosen (E.O. section 2 (d)). The commenter
stated that the above stated recommendation is consistent with
the CAAA emission standards. The commenter also noted that
section 112(d) (2) requires the Administrator to establish such
standards "taking into consideration the cost of achieving such
emissions reduction requirements...." The commenter also pointed
out that section 112(f) requires the Administrator to take "into
consideration costs, energy, safety, and other relevant factors,
and adverse environmental effect" when establishing requirements
and setting standards. The commenter also strongly recommended
that the Office of Management and Budget (OMB) review the NESHAP
prior to promulgation.
Two commenters (IV-D-35, IV-D-83) pointed out that the EPA
indicated that it has classified the aerospace NESHAP rule as
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"non-significant" under Executive Order 12866 and, therefore, the
proposed rule was not reviewed by OMB. The commenters were
concerned about the potential for added cost associated with some
of the requirements in the proposal. The commenters believe that
the cost associated with the Aerospace NESHAP will significantly
impact the industry and DoD. The commenters strongly recommended
that the proposed rule (and its changes) undergo review by OMB
pursuant to Executive Order 12291 (46 FR 13193).
Response: As commenter IV-D-35 pointed out, 84.1 percent of
their estimated capital cost comes from the control of inorganic
HAP and 9.4 percent of the total capital costs is derived from
the control of organic HAP. The data collected by the Agency
indicated that all facilities currently use filters to capture
and collect inorganic emissions from depainting operations.
Additionally, the depainting standard, primer and topcoat
application standard, and the chemical milling maskant standard
all contain provisions for compliant coatings. The commenter may
use these coatings in addition to the filtering device already in
place for topcoat and primer operations. Such an action on the
commenter's part would mean that no additional inorganic control
devices would be required. Additionally, no control devices for
organic HAP would be required if compliant coatings, strippers,
and maskants were used. If the commenter decides to use non-
compliant coatings, the control devices will have to be installed
in order to assure the public's safety.
Additionally, the commenter's study addressed areas that the
EPA has no control over or did not regulate, such as Military
Construction (MILCON) Funding Requirements and Emission Credits.
The final rule does not contain control requirements for
facilities that use mechanical sanding, flexible primers, or
perform touch-up and repair coating operations. The final rule
was also submitted to OMB for review.
Comment: Commenter IV-D-50 stated that the EPA's economic
model does not account for the loss in the foreign repair
business. The commenter pointed out that a significant portion
of their repair business comes from foreign-based airlines, such
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as Airbus. The commenter also pointed out that they must compete
with foreign repair facilities, which will not be subject to the
proposed regulations. The commenter suggested that, since they
are faced with the large expense of complying with the proposed
rule, they may not be able to remain competitive with their
competition.
Response: The EPA's goal is to protect the environment in
accord with the statutory mandates without inflicting undue
economic burdens on the industry. The EPA does not have the
authority to set policy for industries located outside the United
States boundaries. The EPA believes that, as the world leader in
aerospace technology, this industry will continue to perform the
majority of rework operations on aircraft produced domestically
and internationally due to the technologies used by domestic
rework facilities and the skills of the aerospace employees.
Comment: Three commenters (IV-D-29, IV-D-37, IV-D-50)
believe that the estimated nationwide costs of compliance with
the Aerospace NESHAP are grossly underestimated.
Commenter IV-D-50 claimed that the capital cost for an
incineration system to meet the proposed regulation for their
non-major source Repair Division facility will cost in excess of
$1,000,000. The commenter stated, with all due respect, given
the 2,800 facilities that the EPA estimates will be affected by
the proposed rules, the EPA's estimate that the implementation
cost of rules will be only $16.7 million is ridiculous.
Commenter IV-D-37 claimed that airlines that fly painted
aircraft will be required to have separate dedicated hangars for
depainting and for primer and topcoat application. According to
the commenter, construction costs for hangars that can
accommodate large commercial aircraft and are equipped with
ventilation and filtration systems in compliance with the NESHAP
are presently estimated at $50 to $70 million each.
Response: The docket contains information indicating that
almost none of the affected facilities will have to build hangars
as a result of the NESHAP. In addition, the EPA has not
regulated non-major sources under the NESHAP. Sources of VOC
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emissions at these other facilities are being addressed in the
Aerospace CTG.
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16.0 OTHER COMMENTS
16.1 NESHAP FORMAT
Comment: Two commenters (IV-D-12, IV-D-23) recommended that
the applicability determination requirements be included in the
regulation itself. The commenters stated that reference to the
general provisions for these determinations is not acceptable,
since review of these provisions is necessary to determine if a
source is even subject to the standards. According to the
commenters, the applicability section should be completely self-
contained so owners and operators may determine if the rule
applies to them on the basis of a single document.
Commenter IV-D-12 stated, however, that it is expeditious
for other sections of this standard to contain references to the
General Provisions, rather than repeating text from part 63,
subpart A. The commenter, therefore, recommended that the
following language (or something similar) be added to the
Applicability section to assist affected sources.
"Note: Subpart A of Part 63 of the Code of Federal
Regulations (General Provisions) is needed to understand
some requirements of the standard. Subpart A can be
obtained from the Federal Register publication of (insert
FR# and date) or by contacting (insert EPA contact) of the
EPA for copies."
Commenter IV-D-29 noted that the proposed rule provides
exemptions for a number of activities in specific sections of the
rule. The commenter believes that these exclusions would be more
useful and more understandable if they were stated together in
one place.
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Conunenter IV-D-12 suggested that the standards be
reorganized into subcategories -- cleaning operations, primer and
topcoat application, depainting operations, chemical milling
maskant application, and handling and storage of waste. Each
subcategory would include the specific standards, compliance
dates and determinations, test methods and procedures,
monitoring, and recordkeeping and reporting requirements
associated with each subcategory. The commenter believes that,
while this would result in some repetition and multiple
documents, the simplification would result in a much more
understandable rule.
Four commenters (IV-D-12, IV-D-23, IV-D-29, IV-D-44)
complimented and commended the EPA for the inclusion of extensive
tables to summarize the requirements of the proposed NESHAP. The
commenters stated that the tables provided in this NESHAP are a
simple, straightforward, valuable tool in understanding and
applying the requirements of Aerospace MACT. The commenters
believe that sources will be able to identify early (without
muddling through dozens of pages) whether they must comply with
the standard. Commenter IV-D-23 encouraged the EPA to continue
to strive to simplify regulations so that the need for such a
tool is eliminated in the future. Commenter IV-D-29 strongly
believes, however, that the Summary Table should be moved to the
preamble, where such clarifying language is more appropriately
situated. The commenter also added that any revisions to the
final rule should be reflected in the Summary Table.
Commenter (IV-F-l) suggested that the EPA refrain from
promulgating summary tables as part of the final regulations.
The commenter believes that inclusion of tables in the final
regulation engenders disputes and confusion with respect to the
interpretation and enforcement of the rule.
Response: The EPA inserted the summary table as an appendix
in the final rule, and has also included the table in the
preamble to the rule. However, the EPA would like to dispel the
impression that a facility can read the summary table and
accurately determine if they are affected by the rule. The EPA
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recommends that all potential affected sources read the complete
final rule to determine its applicability to their operations.
Additionally, the EPA has added a provision to the
applicability section to provide affected sources with the
reference for subpart A of part 63, as suggested by the
commenter. The EPA believes that this action deletes the
duplication that would result if the language of subpart A was
included in the final rule.
Comment: Commenter IV-D-06 pointed out that under Chemical
Milling Maskant Operations - Standards - Uncontrolled Maskants 4.
it states that "Both controlled and uncontrolled maskants cannot
be averaged together" and that this restriction only appears in
the table. The commenter noted that if it is the EPA's intent to
apply this restriction to chemical milling maskants, then it
should be referenced in the maskant section (§63.747).
Response: The EPA has revised the standard which now
specifies that control devices used to capture the emissions from
maskant operations must achieve an overall control efficiency of
at least 81 percent. In addition, the EPA will not allow
controlled and uncontrolled emissions to be averaged together.
Comment: Commenter IV-D-12 recommended that the alternative
composite vapor pressure limit of 45 mm Hg or less for hand-wipe
cleaning solvents contained in §63.744(b)(2) be added to Table 3
to make clear that there are three compliance options available.
Further, the commenter suggested that Table 3 be positioned in
the rule before §63.744(c), the section on spray gun cleaning, to
clearly indicate that the limits in Table 3 are for hand-wipe
cleaning.
Response: The EPA has specified three compliance options
for hand-wipe cleaning solvents in the final rule. Two solvent
composition compliance options were specified, 45 mm Hg vapor
pressure or the criteria in Table 3. There are different
recordkeeping requirements for each of the two options and,
therefore, the EPA will not add 45 mm Hg vapor pressure solvents
to Table 3. The EPA has adopted the commenter's recommendation
and positioned Table 3 before §63.744 (c) so that facilities will
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clearly know that the solvent specifications apply to hand-wipe
cleaning only.
Comment: Commenter IV-D-29 noted that the title of
§63.749 (f) is "Organic HAP Emissions-Depainting Operations," but
in subparagraph (2) of this section, the EPA addresses inorganic
HAP from depainting operations. The commenter believes that the
EPA should either separate the organic and inorganic HAP
requirements for depainting operations, consistent with its
approach to primer and topcoat operations, or relabel this
section.
Response: The EPA has revised the depainting operations
standard extensively since proposal. In addition, the compliance
dates and determinations standard has been revised to reflect
these changes. The EPA has also incorporated the commenter's
recommendation into the revisions.
16.2 PUBLISHING THE PROPOSED RULE IN THE FEDERAL REGISTER
Comment: Four commenters (IV-D-12, IV-D-23, IV-D-29, IV-D-
47) objected to the omission of the proposed rule from the
Federal Register. Three commenters (IV-D-12, IV-D-23, IV-D-29)
noted that downloading the proposed rule from the EPA's
Technology Transfer Network is not always a viable option for all
interested parties and requesting a copy by mail reduces time
from the limited comment period. Commenter IV-D-23 stated that
in order for regulatory agencies and industry to fully understand
the proposal, it is necessary to review the actual regulation.
Commenter IV-D-29 stated that failing to publish the proposed
rule inhibits the public comment process.
Commenter IV-D-12 stated that it is critical to have easy
access to the proposed rule, since the rule will apply to new
sources from the date of proposal, not the date of promulgation.
The commenter suggested that, if something is to be left out of
the Federal Register, it would make more sense to print the
proposed rule and leave out the preamble - those who need such
detailed information on the development of the regulation can
then obtain it.
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The commenter noted that at the beginning of the proposal it
states "This section of the Federal Register contains notices to
the public of the proposed issuance of rules and regulations.
The purpose of these notices is to give interested persons an
opportunity to participate in the rulemaking prior to the
adoption of the final rules." According to the commenter, not
printing the text of the rule is inconsistent with the intent of
this statement. The commenter further stated that, since there
is not an official document that contains the draft rule
language, it is impossible to reference the proposal in other
official documents.
Commenter IV-D-47 stated that it is not clear that the EPA's
publication of only the preamble to the proposed rule complies
with the notice and comment requirements of the Administrative
Procedure Act, 5 U.S.C. § 553(b)(3).
Response: [This is a policy question which will be
addressed in the final document.]
16.3 NEED FOR THE STANDARD
Comment: Commenter IV-D-57 claimed that small manufacturing
companies have an extremely difficult task in merely being aware
of the myriad of Federal, State, and local environmental laws.
The commenter stated that the processes covered under the
proposed rule are already governed by existing regulations, along
with their attendant reporting and recordkeeping requirements.
The commenter believes that the proposed rule is redundant
and unnecessary for most of the establishments that would be
covered under the rule. The commenter also believes that the
proposed rule is extremely untimely, and would further weaken the
U.S. aerospace industry as the leading U.S. export industry,
while stimulating foreign competitors' penetration into world
markets of American producers.
Response: The EPA is mandated by Congress in section 112 of
the amended Clean Air Act to establish HAP emission standards for
the aerospace industry on a national level. The proposed
standards were based heavily on existing regulations in
California, where 25 percent of the industry is located. These
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facilities demonstrate that the emission limits established in
this rule are achievable without creating an excessive economic
burden or threatening the viability of the industry.
16.4 RCRA REQUIREMENTS
Comment: Commenter IV-D-22 stated that the proposed rule
encourages the use of new unscrutinized solvents which are not
covered under the Resource Conservation and Recovery Act (RCRA)
and that the EPA should consider amending RCRA at the next
opportunity to cover new solvents that may be widely used.
Response: The final aerospace rule requires that solvents
meet composition and/or vapor pressure requirements only, and
does not make any representation as to whether particular
solvents may or may not be covered by RCRA. The Policy Planning
and Standards Group is responsible for developing and
implementing the NESHAP. The Agency has another division which
evaluates chemicals on an ongoing basis to determine the RCRA or
non-RCRA status of each chemical or compound. This rulemaking
effort does not conflict with the RCRA requirements and exempts
RCRA waste from the reporting requirements. Wastes that are
later determined to be RCRA waste will follow RCRA requirements.
16.5 DELEGATION OF AUTHORITY
Comment: Five commenters (IV-D-35, IV-D-37, IV-D-43, IV-D-
52, IV-D-58) stated that flexibility should be added to the rule
to allow State and local agencies to require alternative
recordkeeping, reporting, and monitoring that are cost-effective
and are equally effective in demonstrating compliance with the
proposed NESHAP. The commenters believe that this would reduce
the financial burden on sources.
Commenter IV-D-52 was concerned about Federal requirements
for sources of HAP since existing permitting and risk management
programs in their AQMD address many of the same toxics concerns.
The commenter pointed out that they have numerous rules and
regulations in place which limit emissions from the significant
source categories in their region, including Regulation 8, Rule
29, Aerospace Assembly and Component Coating Operations. The
commenter believes that it is critical for the rulemaking efforts
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at the EPA to recognize the importance of established local
programs, and provide flexibility to minimize negative impacts on
these programs wherever possible.
Commenter IV-D-58 urged the EPA to allow for the use of
equivalent control strategies, such as the South Coast Air
Quality Management District (SCAQMD) Rules 1401 and 1402 and its
proposed Regional Clean Air Incentives Market ("RECLAIM") for
VOC, as an alternative method of accomplishing emissions
reductions mandated in the EPA's proposed NESHAP. The commenter
is concerned that the Aerospace NESHAP as currently proposed
adversely affects the anticipated benefits of the proposed VOC
RECLAIM. The commenter stated that the SCAQMD has developed
regulatory programs that achieve equivalent environmental
benefits to the Aerospace NESHAP and requested that the EPA
explicitly recognize the approvability of such alternative
programs that do not require the retention of VOC-content limits
and burdensome recordkeeping and reporting obligations that the
proposed VOC RECLAIM program would eliminate.
The commenter provided an explanation of how the RECLAIM
program works. The program includes facility-wide emission caps
in place of specified control strategies and VOC-content limits.
The commenter stated that facility caps are represented in the
form of tradeable RECLAIM trading credits, and that the program
allows averaging not only within facilities but across facilities
to meet the requirements of the District's ozone plan.
Additional details on the program were supplied by the commenter.
The commenter suggested that the RECLAIM program and the
Aerospace NESHAP are clearly incompatible as currently proposed.
The commenter pointed out that, not only is the NESHAP proposal
based on "command and control" VOC and HAP limits, but it
explicitly prohibits intra- and extra- facility trading which is
the cornerstone of the RECLAIM program.
The commenter requested that the EPA consider the
approvability of an alternative program in the South Coast Air
Basin and other areas that adopt RECLAIM-type programs, which are
consistent with the philosophy of the RECLAIM program and at the
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same time meet the environmental objectives of the Aerospace
NESHAP. The commenter claimed that the combination of the
RECLAIM program which achieves basin-wide emission reductions
through the program's facility caps, together with the District's
recently adopted air toxics programs, A.B. 2588 and District
Rules 1401 and 1402, which relies on risk-based standards in lieu
of VOC-content and HAP limits, can meet the criteria of an
alternative program as stated under section 112(1} of the CAA.
The commenter stated that only risk-based approaches, like
existing District Rules 1401 and 1402, are consistent with the
market-based approaches contained in RECLAIM.
The commenter believes that the policy of assuring
compatibility among the various regulatory programs adopted to
comply with Federal Clean Air Act requirements is also consistent
with the Agency's Common Sense Initiative. The commenter
requested the Agency's help in developing compatible regulatory
programs.
The commenter also stated that detailed daily recordkeeping
and reporting by material type is extremely burdensome and costly
and is one of the areas where Southern California companies seek
relief by moving to a RECLAIM program. The commenter believes
that equivalency demonstrations under section 112(1) should
include the ability for the EPA to approve recordkeeping and
reporting systems that impose less frequent and less detailed
reporting than that proposed in the Aerospace NESHAP. The
commenter noted that detailed reporting is not necessary for the
risk-based approaches represented in Rules 1401 and 1402.
According to the commenter, as long as the recordkeeping and
reporting system is sufficient to provide adequate enforcement of
the regulatory strategy selected, then alternative recordkeeping
programs should be approved.
Response: The EPA has worked very closely with the States
and this industry to address their concerns and develop a rule
that can be implemented without undermining the effectiveness of
local programs. The EPA is required to develop a MACT standard
that is applicable on a national basis and, as such, many local,
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State, and Federal agencies have provided input. States and
local agencies may always implement standards that are more
stringent than the NESHAP; however, providing flexibility to
local agencies to alter the NESHAP requirements would be
detrimental to the intent of the rule. All State and local
agencies may submit any air quality control program to the EPA
for consideration under section 112(1) of the Act, and the EPA
encourages the California delegations to submit their programs
for equivalency determinations.
16.6 AMENDING REFERENCED TEST METHODS
Comment: Commenter IV-D-33 stated that they, along with
local agencies in California, have done considerable work on
developing and improving test methods for coatings. The
commenter noted that some of these changes have been incorporated
into the U.S. EPA reference method by revision to the State
implementation plan (SIP). However, the commenter also noted
that most changes have not been incorporated into the SIP because
the current process of amending reference test methods is
extremely time-consuming and resource intensive. The commenter
recommended that the EPA streamline the process for amending its
reference test methods.
Response: The EPA has taken steps to streamline the process
for amending the reference methods. Although improved, the
process is still time-consuming. The EPA will continue to seek
areas in which testing can be improved and will work to implement
changes in a timely manner.
16.7 COLLECTION OF FEES FROM EMISSIONS
Comment: Commenter IV-D-31 stated that EPA has the
authority under the CTG to mandate reductions over a 10-year
period and that the EPA should use that authority to leverage
continued innovation in emission control. The commenter,
therefore, recommended that the EPA set technology enforcing
emission reduction targets for facilities, to be obtained 5, 7,
and 10 years after issuance of the CTG. The commenter proposed
that a requirement of 20 percent reduction for the 5th year, a 30
percent for the 7th year, and a 50 percent for the 10th year,
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each from the current MACT level of control. The commenter
recommended that, in the event that emissions targets are not
met, the permitting agency collect emission fees. The commenter
provided recommended emission fee levels and recommended that
these fees be divided between facilities that exceeded their
targets and the State, which would receive 20 percent of the fee.
The commenter stated that the Clean Air Act authorizes using fees
to provide incentives for achieving emission reductions and to
fund the administrative costs of State programs under the Act
[§182(g)(4)(B)]. The commenter also stated that such a scheme
would set up competition to meet or exceed emission reductions
and reward success.
The commenter provided an algorithm for emissions reduction
and a fee schedule.
Response: The EPA will address the issue of emissions fees
in the CTG.
16.8 MACT DETERMINATION
Comment: Two commenters (IV-D-27, IV-D-29) believe that, in
some circumstances, the EPA has proposed standards that are more
stringent that the "MACT floor" and exceed the maximum achievable
controls within the industry. Commenter IV-D-27 believes that
the EPA has proposed burdensome requirements for the handling and
storage of non-RCRA wastes. The commenter claimed that the EPA
cannot show--and has not even attempted to show--that these waste
stream control measures reflect current practices in the
industry, not to mention the best controlled 12 percent of
existing sources, and therefore, represent the MACT floor.
Commenter IV-D-31 stated that the statute requires the
maximum achievable emission reductions and that cost
considerations can, in some cases, justify decisions to
promulgate emission limitations not fully reflective of the best
technology, provided that the emission limitations do not go
below the MACT floor. The commenter also claimed that, in this
case, many of the most stringent emission limitations actually
save facilities money. According to the commenter, no one should
say that the costs make these emission levels unachievable as
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they amount to 0.01 percent of the total industry production
costs. Therefore, according to the commenter, the most stringent
limitations should be placed on the industry.
The commenter further stated that the proposal seems to
require less than the best achieved emission limitation for new
sources. The commenter stated that this is inconsistent with the
Act's floor requirements and, in some cases, such as with hand-
wipe cleaning, the emission limitation is less stringent than the
properly determined floor for existing sources. According to the
commenter, this is not permissible.
Commenter IV-D-29 stated that they support equal controls
for both new and existing sources. According to the commenter,
if the EPA were to reverse course and propose stricter standards
for new sources, a new proposal and a new opportunity for public
comment would be legally required.
Response: The EPA has deleted the handling and storage
provisions for non-RCRA waste, because the required supporting
data necessary to implement such provisions are not available.
Additionally, the MACT standards include a new source
provision for primer and topcoat application operations involving
coatings that contain cadmium and chromium. This is the only new
source requirement that the EPA has identified. Further, the
Agency's economic analysis of the industry indicated no new
growth over the next several years for this industry. The rule
will be reviewed 7 years from promulgation and, if warranted, new
requirements can be implemented.
Comment;: Commenter IV-D-39 supported most aspects of the
proposed rule and considered the limits contained therein
representative of MACT in this industry. The commenter noted
that certain innovative techniques were used in the development
of the proposed MACT limits, such as defining various coatings
types as source categories for determination of the MACT floor,
and using VOC as a surrogate for HAP. The commenter stated that
they have supported the use of these techniques in the
development of this standard, but cautions the Agency that 'these
techniques may not be applicable in other surface coating
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standards. Specifically, the commenter stated that they would
strongly object to the inference that since VOCs were used as a
HAP surrogate in this instance, VOC in general should be
considered to be hazardous or should be treated in a similar
fashion to HAPs. In the case of the Aerospace NESHAP, the
commenter believes this strategy proved to be useful and resulted
in desirable coordination of the Agency's requirement to control
both VOCs and HAPs. Again, however, the commenter indicated that
this approach should not be considered universally applicable in
surface coating MACT standard development.
Response: The EPA did not intend to imply that HAP and VOC
have the same characteristics. The EPA does appreciate the
commenter's opinion and will consider it in future rulemaking
efforts.
Comment; Commenter IV-D-52 recommended that the
housekeeping requirements for solvent cleaning operations
specified in §63.744(a) be extended to apply to coatings,
thinning solvents, and chemical strippers.
Commenter IV-D-31 stated that the housekeeping and work
practice measures proposed constitute good application of common
sense.
Response: The EPA has adopted the commenters'
recommendations and the final rule contains waste handling and
storage requirements for coatings and chemical strippers.
Comment: Commenter IV-D-13 believes that this rule will
dramatically impact the general aviation community. The
commenter has not been able to find anyone in the general
aviation community who was a participant in section 114
questionnaire survey. The commenter stated that the survey
appears to be the primary basis for the EPA's decisions and
assumptions on how to go forward with this rulemaking effort.
The commenter also stated that it appears that the EPA has
determined that the general aviation segment of the marketplace
has no significant impact on environmental emissions levels and
asked: Is this why only the military and commercial aspects were
addressed in the survey and the proposed rulemaking?
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Response: The EPA sent a information request under section
114 to Beech Aircraft and conducted on-site information
collection at Beech Aircraft, Cessna, Hunting Air (now Stevens
Aviation), and LearJet. These information gathering efforts
provided the Agency with valuable information concerning the
general aviation segment of the industry. In addition, these
four facilities are major sources and the vast majority of
general aviation facilities are non-major sources which will not
be covered by the NESHAP.
16.9 STANDARDS: GENERAL
Comment: Commenter IV-D-29 stated that proposed §63.743 was
very unclear as to exactly which sections of the General
Provisions apply to aerospace operations. The commenter noted
that the second sentence of the proposed section states that
"each owner or operator of an affected source" is subject to
three specific sections of the General Provisions "except as
provided in paragraphs (a)(4) through (a)(9) of this section and
in Table 2" and that these other provisions in turn reference
both portions of the three specific previously cited sections, as
well as other sections and subsections. The commenter pointed
out that nowhere is there any specific description of the
provisions which override the general provisions. The commenter,
therefore, recommended that these relationships be clarified in
the final rule.
Three commenters (IV-D-27, IV-D-29, IV-D-35) noted that
proposed §63.743(b) restates and strengthens the requirement in
the General Provisions for "maintenance plans." According to two
of the commenters (IV-D-29, IV-D-35), when implementing this
requirement, the EPA needs to recognize that these requirements
are far more applicable to combustion systems or recovery systems
than to particulate filter devices intended for control of
inorganic HAP. The commenters believe that the development of a
comprehensive operation and maintenance plan for particulate
filters represents an excessive burden to the industry without a
commensurate environmental benefit. The commenters stated that
particulate filtering systems are generally not prone to startup
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and shutdown malfunctions as required for the Operating and
Maintenance Plans. Conunenter IV-D-35 suggested that it is more
appropriate to let the State or local regulatory agency
determine which level of enforcement is best for them to meet the
requirements. The commenter noted that manufacturers'
specifications or some other negotiated method could then be
used. Commenter IV-D-27 stated that §63.743(b) needs to be
clarified to allow particulate filtering systems to be operated
in accordance with manufacturers' operating instructions to
ensure efficiency.
The commenter recommended the following revision:
"§63.743 Standards: General:
(b) Operating and maintenance plan. Each owner or operator
that uses an air pollution control device or equipment to
control HAP emissions shall prepare and operate in
accordance with a startup, shutdown, and malfunction plan in
accordance with §63.6. Particulate filtering systems must
be operated per the manufacturers instructions and are
exempt from a startup and shutdown plan. In addition to the
information required in §63.6, this plan shall also include
the following provisions:"
Commenter IV-D-35 recommended that the following sentence be
added to §63.743(b):
"Any Operation and Maintenance Plan requirements shall be
delineated in the appropriate Title V operating permit."
Commenter IV-D-35 recommended that the following be added as
a new section:
"§63.743(d)
As new materials, techniques, and technologies evolve,
particular materials, techniques, and technologies called
out in individual paragraphs may be obsolete, removed from
service, or supplanted by advances to the state of the art.
When the superiority of such advances has been established
in practice, the administrator shall issue a universal
determination that the new material, technique, or
technology may be substituted for the requirement specified
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in any paragraph under these rules. Until such
determination is made, substitution of advanced materials,
techniques, or technologies may be negotiated by the
administrator's representative on a case-by-case basis."
The commenter stated that the above provision will allow the
Aerospace NESHAP to evolve and remain valid as new materials,
techniques, and technologies are introduced into the aerospace
industry.
Response: The EPA agrees with the commenters and believes
that comprehensive startup and shutdown plans are not required
for particulate filters operated according to manufacturer's
specifications. The EPA has adopted the following revision in
order to remove particulate devices from the requirements
specified in the General Provisions. Final §63.743(b) states:
11 (b) Operation and maintenance plan. Each owner or
operator that uses an air pollution control device or
equipment to control HAP emissions shall prepare and operate
in accordance with a startup, shutdown, and malfunction plan
in accordance with §63.6. Dry particulate filter systems
operated per the manufacturer's instructions are exempt from
a startup and shutdown plan. A startup and shutdown plan
shall be prepared for facilities using locally prepared
operating procedures. In addition to the information
required in §63.6, this plan shall also include the
following provisions:"
16.10 VOC AND HAP EMISSIONS IN NONATTAINMENT AREAS
Comment: Commenter IV-D-30 noted that the Aerospace NESHAP
is applicable to those facilities that are major sources of HAP
and that the Aerospace CTG will be applicable primarily in
nonattainment areas. The commenter pointed out that some of
their major sources are located in areas of attainment and so
would not necessarily be affected by the CTG requirements for VOC
restrictions. The commenter stated that, as proposed, the NESHAP
would restrict both HAP and VOC for primers, topcoats, and
chemical milling maskants; and vapor pressure for cleaning
materials. The commenter claimed that this could require them to
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replace materials that do not contain any HAP, regardless of
whether the material is used in a nonattainment area. Therefore,
the commenter would like the EPA to clarify its intent regarding
the restriction of VOC in a document related to the restriction
of HAP.
Response: The EPA's analysis indicated that all coatings
contained VOC and HAP and that VOC content was almost always
higher in the materials evaluated than the HAP content. The EPA
determined that, frequently, VOC is used as a surrogate for HAP.
The EPA has an approved method for VOC, Method 24. Over 95
percent of the affected sources are in nonattainment areas. The
industry requested that the EPA provide a "nationally" consistent
regulation. The EPA has responded by providing a national
standard with an approved test method.
16.11 VARIANCE PROVISION
Comment: Commenter IV-D-29 stated that they believe the EPA
must include in the final rule a procedure under which affected
sources can petition the EPA for relief from regulatory
requirements when compliance has proven impossible for
unanticipated reasons not addressed during their rulemaking.
According to the commenter, the need for such a "fundamentally
different factor" variance has long been legally established in
cases under the Clean Water Act, and applied in many contexts by
the EPA. The commenter believes that the need is equally clear
here.
The commenter stated that compliance with the Aerospace
NESHAP will require affected sources to simultaneously identify,
evaluate, and qualify many new materials for many new uses. The
commenter pointed out that the MACT floor analysis was heavily
based on certain California air district regulations. The
commenter also pointed out that many of the activities for which
new materials will be necessary either do not occur in
California, or comply with California standards only through the
use of ozone-depleting chemicals that will shortly be
unavailable. The commenter claimed that the interaction between
the primer/topcoat requirements and the depainting requirements
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is just one example of this problem. The commenter noted that
the proposed rule imposes new requirements on depainting and at
the same time requires a change in the coatings used on the
exterior surface of the aircraft. The commenter claimed that the
newer depainting techniques that meet the 12 percent MACT floor
have not been proven on these new coatings. According to the
commenter, there is no evidence to show that all these
substitution efforts will succeed on schedule. Further, the
commenter stated that the effect of the large number of materials
and process changes cannot be completely predicted today, and
neither can the final impact to employee safety as a result of
the changes. The commenter stated that in such circumstances a
variance procedure is appropriate and legally required.
Therefore, the commenter recommended revising §63.741(b) and
adding §63.741(g) as follows:
§63.741(b) The owner or operator of an affected source
shall comply with the requirements of this subpart and of
subpart A or this part, except as specified in §63.743(a)
and S63.741(g).
(g) The owner or operator may apply for a variance from the
provisions of this subpart. The variance application shall
be in writing and shall demonstrate that the variance
request reflects factors fundamentally different from those
on which the standards in this subpart were based and the
alternative standards that are justified in light of those
fundamentally different factors. The variance application
shall be submitted to the Regional Administrator or to the
state or local jurisdiction in those situations where an EPA
approved program exists.
Response: [This is a policy question which will be
addressed in the final document.]
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1. REPORT NO.
453/R-97-003b
TECHNICAL REPORT DATA
(Please read Instructions on reverse before completing)
1.
4. TITLE AND SUBTITLE
Aerospace Manufacturing and Rework Industry--
Background Information and Promulgated Standards
7. AUTHOR(S)
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Midwest Research Institute
401 Harrison Oaks Boulevard
Suite 350
Gary, North Carolina 27513
12. SPONSORING AGENCY NAME AND ADDRESS
Emission Standards Division (Mail Drop 13)
Office of Air Quality Planning and Standards
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
3. RECIPIENT'S ACCESSION NO.
May iW/
6. PERFORMING ORGANIZATION CODE
8. PERFORMING ORGANIZATION REPORT NO.
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
68-D1-0115
13. TYPE OF REPORT AND
14 SPONSORING AGENCY
EPA/200/04
PERIOD COVERED
CODE
15. SUPPLEMENTARY NOTES
EPA Work Assignment Manager: Barbara Driscoll, ESD/PPSG
16. ABSTRACT
National emission standards for control of HAP emissions from aerospace manufacturing and rework
facilities were published in 60 FR 45948, September 1 , 1995. This regulation was promulgated under the
authority of Section 1 12 of the Clean Air Act. The standards will reduce air toxics from all major source
aerospace facilities (defined as those facilities that emit, or have the potential to emit, more than 9.1 Mg/yr
[10 tons/yr] of any HAP or 22.7 Mg/yr [25 tons/yr] of any combination of HAP.)
This document provides: the basis for the revisions made to the standards between proposal and
promulgation; a summary of the comments submitted and the responses to these comments; and summary
of the changes made since proposal.
17.
a. DESCRIPTORS
KEY WORDS AND DOCUMENT ANALYSIS
b. IDENTIFIERS/OPEN ENDED TERMS
Air Pollution Cleaning Operations Air Pollution Control
Aerospace Manufacturing Surface Coating MACT
and Rework (Painting) Coating Operations
Hazardous Air Pollutants Depainting Cleaning Operations
18. DISTRIBUTION STATEMENT
Release Unlimited
19. SECURITY CLASS (Report)
Unclassified
20. SECURITY CLASS (Page)
Unclassified
c. COSATI Field/Group
21. NO OF PAGES
424
22 PRICE
EPA Form 2220-1 (Re*. 4-77)
PREVIOUS EDITION IS OBSOLETE
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U.S. Environmental Protection Agency
Region 5, Library (PL- 12J)
77 West Jackson Boulevard, 12th Floor
Chicago, IL 60604-3590
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