EPA 453/R-97-003c
PB 98-158538
National Emission Standards for Hazardous Air Pollutants
(NESHAP) for the Aerospace Manufacturing and Rework Industry
Background Information for Promulgated Standards
ADDENDUM
January 1998
NESHAP
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National Emission Standards For Hazardous Air Pollutants
(NESHAP) for the Aerospace Manufacturing and Rework Industry
Background Information for Promulgated Standards
ADDENDUM
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
January 1998
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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. ><3brdan (Date]
Directed, 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 the 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. Barbara Driscoll
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 (NTIS)
5285 Port Royal Road
Springfield, VA 22161
Telephone: (703) 487-4650
U.S. EPA Library Services Office (MD-35)
U.S. Environmental Protection Agency
Research Triangle Park, N.C. 277111
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5. 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: 1
• 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 Bulletin Board: Clean Air Act Amendments
• Select menu item: Recently Signed Rules
IV
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TABLE OF CONTENTS
1.0 SUMMARY 1-1
2.0 COMMENTS 2-1
2.1 REGULATORY TEXT/CITED REFERENCES 2-1
2.2 TYPOGRAPHICAL ERRORS 2-2
2.3 DEFINITIONS (NONSPECIALTY COATINGS) 2-3
2.4 DEPAINTING/CHEMICAL STRIPPING . 2-7
2.5 MISCELLANEOUS NESHAP ISSUES 2-15
2.6 NOT RELEVANT TO PROPOSED AMENDMENTS 2-24
2.7 SPECIALTY COATING DEFINITIONS 2-42
2.8 CTG ISSUES 2-43
2.9 METHOD 319 2-46
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1.0, SUMMARY
On September 1, 1995, the U. S. Environmental Protection
Agency (EPA) promulgated national emission standards for
hazardous air pollutant (HAP) emissions from major sources in the
aerospace industry (.60 PR 45948) . These final standards
implemented section 112(d) of the Clean Air Act as amended in
1990 (the Act). On October 29, 1996, the EPA proposed amendments
to the final rule and release of a draft control techniques
guideline (CTG) document (61 FR 55842). There were 18 comment
letters (see Table 1-1) submitted by 19 different commenters,
which consisted primarily of trade associations, component
suppliers and State and local air pollution control agencies. In
addition, comments were received from one general aviation
facility, private environmental organizations, and U.S.
Government agencies. Summarizes 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
(amendments) made to the final NESHAP. This document is an
addendum to Volume II of "National Emission Standard for
Hazardous Air Pollutants (NESHAP) for the Aerospace
Industry - Background Information for Promulgated Standards,"
July 1995, EPA Document No. EPA/R-97-003b (Docket A-92-20,
item III-B-1). This report also includes a discussion of the
changes made to the draft CTG in finalizing the CTG document.
The proposed amendments requested comment regarding
corrections to several references in the rule; revisions and
additions to definitions; clarification of the applicability of
the cleaning operations standards; clarification of the
applicability of the rule to space vehicles; addition of
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standards for Type I chemical milling maskants; revision of
standards for new and existing sources using dry particulate
filters to control emissions from topcoat and primer application
and depainting operations; addition of a test method for
determining the filtration efficiency of dry particulate filters;
addition of an exemption for certain water-reducible coatings;
addition of an essential use exemption for cleaning solvents;
clarification of compliance dates; clarification of the
applicability of new source MACT to spray booth standards;
clarification of the requirements for new and existing primer and
topcoat application operations; clarification of monitoring
requirements for dry particulate filter usage; addition of
Appendix A to this subpart containing definitions for specialty
coatings, and addition of a cross reference to requirements in
the General Provisions in Subpart A of part 63. The EPA
announced in the same Federal Register notice the availability of
a draft CTG document for control of volatile organic compound
(VOC) emissions from aerospace manufacturing and rework
facilities for public review and comment. This document was
prepared to assist States in•analyzing and determining reasonably
available control technology (RACT) for stationary sources of VOC
emissions located within ozone national ambient air quality
standard nonattainment areas.
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TABLE 1-1.
LIST OF COMMENTERS ON THE PROPOSED AMENDMENTS
TO THE AEROSPACE NESHAP
Item No. In
Docket A-92-20
VI-B-48
VI-B-49
VI-B-50
VI-B-51
VI-B-52
VI-B-53
VI-B-54
VI-B-55
VI-B-56
VI-B-57
VI-B-58
VI-B-59
VI-B-60
VI-B-61
VI-B-62
VI-B-63
VI-B-64
VI-B-65
VI-B-66
Commenter, affiliation, and date
Keith, P. Gutreuter, Air Technologies, Inc., Ottawa, KS. November 6, 1996.
Nancy, A. Storoz, Aviation Specialist, Elf Atochem, North America. November 25,
1996.
Christian Sasfai, Stevens Aviation, Peachtree, GA. December 13, 1996.
Al Vatine, LMS Technologies, Inc., Edna, MN. December 17, 1996.
Glynn Rountree, Director Safety, Health and Environmental Affairs. Aerospace
Industries Association, Washington, D.C. December 20, 1996.
Benjamin W. Shaw, Senior Manager, Air Toxics Team Stationary Source
Compliance, South Coast Air Quality Management District, Diamond Bar, CA.
December 20, 1996.
J. W. Motter, Principal Consultant and Owners, Profit Builders, Sylvania, OH.
December 24, 1996.
Donald B. Phillips, Manager R&D/Compliance, Chemco Manufacturing Company,
Inc., Northbrok, IL. December 24, 1996.
M. M. Yamada, Director Air Quality Environmental Compliance Northrop Gruman
Corporation., El Segundo, CA. December 26, 1996.
Robert T. Johnson, Manager—Environmental Compliance Delta air Lines, Atlanta,
GA, December 27, 1996.
James S. Pew, Project Attorney, Natural Resources Defense Council, Washington,
DC. December 27, 1996.
Michael R. Lake, Chief, Engineering Division^ San Diego Air Pollution Control
District, San Diego, CA. December 30, 1996.
Henry Jordan, Air Pollution Specialist/Private Citizen, Sacramento, CA.
December 30, 1996.
Richard K. Ketler, Managing Director Environmental Affairs, Air Transport
Association, Washington, DC. December 30, 1996.
Olga M. Dominguez, Acting Director Environmental Management Division, National
Aeronautics and Space Administration, Washington, DC. December 30, 1996.
Paul Yaroschak, Director, Environmental Compliance and Restoration, Department
of the Navy. Washington, DC. December 30, 1996.
David S. Kircher, Manager-Engineering Puget Sound Air Pollution Control Agency,
Seattle, WA. December 30, 1996.
Michael H. Scheible, Deputy Executive Officer, California Environmental protection
Agency, Sacramento, CA. December 30, 1996.
Stephen P. Risotto, Executive Director, Center for Emissions Control, Washington,
DC. December 30, 1996.
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2.0 COMMENTS
2.1 REGULATORY TEXT/CITED REFERENCES
Comment: Three commenters (VI-B-52, VI-B-61, and VI-B-57)
stated that § 63.743(d)(1) needs to be modified (reworded) to
make the first sentence a complete sentence as follows:
"The owner or operator may ...".
Response: The Agency agrees with the commenters and has
added introductory language to § 63.743(d)(1) in the final
amendments,
Comment; Commenter VI-B-52 noted that § 63.741 (f) lists the
specific exemptions from coverage by this rule, but does not
mention exemptions listed in the various definitions. The
commenter stated that to be complete, the exemptions in § 63.742
(definitions) should be included in the language used in
§ 63.741.
Response: The Agency agrees with the commenter. The
amended rule contains the suggested language,.
Comment: Commenter VI-B-52 stated that Table 1.--Summary of
Subpart GG of 40 CFR Part 63, references a Table 3 under the
"Description" of "Affected source". The commenter noted that the
correct reference should be to Table 1 to subpart GG--General
Provisions Applicability to Subpart GG.
The commenter also stated that the citation to 63.743(a) is
confusing and suggested that the citation be eliminated.
The commenter also stated that the same Table 1 refers to
Table 4 under "Cleaning Operations" as providing exemptions from
certain housekeeping requirements. The commenter noted that the
correct reference should be § 63.744, Table 1.
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Response: The EPA agrees with the commenter and has revised
Table 1. Summary of Subpart GG of 40 CFR Part 63 to reflect the
appropriate changes. Since this table was included as part of
the preamble when the final rule was published in the Federal
Register, it will be corrected and made available on the TTN.
(The EPA has also prepared an informational brochure
summarizing the aerospace NESHAP requirements which will also be
made available via the TTN.)
Comment; Commenter VI-B-61 suggested clarification to table
references. The EPA needs to revise the table numbering sequence
in the rule. Most of the tables will be referenced often in
compliance reports and Title V operating permits and
applications. It would be much less confusing to have only one
Table 1 in the entire rule, instead of designating the first
table in each section as Table 1.
Response: The Agency has prepared the amendments to the
final rule following guidelines governing the publication of
regulations in the Federal Register. These guidelines specify
the numbering format of tables and figures in regulations.
Comment; Commenter VI-B-64 recommended adding some
descriptive language to table headings for filter efficiency
requirements.
Response; The Agency agrees with the commenter that
descriptive headings aid in the clarity of the filter efficiency .
requirements. The amended regulation contains these descriptive
headings for each of the four tables added to § 63.745.
2.2 TYPOGRAPHICAL ERRORS
Comment; Several commenters noted typographical errors in
the proposed amendments and in the final rule. These comments
are as follows:
Four commenters (VI-B-52, VI-B-57, VI-B-61 and VI-B-63)
noted that § 63.751(c)(2) has a typographical error. It should
read "... system and read and record the water ...".
Two commenters (VI-B-61 and VI-B-57) noted the following
typographical corrections:
§ 63.746(b)(3) delete the word material(s)
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§ 63.744(b)(1) change reference to Table 1
§ 63.750 (g) (5) change to 63^.747
§ 63.750(g)(9)(i) change reference "(g)(2) qr
(3) " to " (g) (2) or (4) »
Response: The Agency agrees with the commenters on all of
these typographical errors except for the missing decimal
(63^/747) in § 63.750 (g) (5) which could not be found in the final
rule text published in the Federal Register. However, the
typographical error was found on the TTN version. The amended
-" rule contains the corrected text for all of the noted
typographical errors.
2.3 DEFINITIONS (NONSPECIALTY COATINGS)
Comment; Two commenters (IV-B-52 and VI-B-63) commented on
the proposed definition of antique aerospace vehicle or
component. Commenter VI-B-52.suggested revising the definition
as follows: means an aircraft or component thereof as defined by
14. CFR part 45, or those nonflight worthy aircraft intended for
permanent display, or used for static manufacturing technology
^demonstrations. Commenter VI-B-63 indicated that the definition
of "antique aircraft" in 14 CFR 45.22 does not include nonflight
.;-,
worthy aircraft displayed at many aircraft museums, military
^squadrons, and manufacturing facilities. Therefore, the
commenter supports the definition in the amendments.
Response: The EPA believes that the passage to which
commenter IV-B-63 refers actually concerns "exhibition" rather
than "antique" aircraft. It was not EPA's intent to add an
exemption for exhibition aircraft that do not meet the "antique
aircraft" definition. In addition, EPA believes that it is not
necessary to expand the scope of the "antique aircraft"
" definition, but the Agency has clarified the definition as
: including aircraft built at least 30 years ago that are not
currently flightworthy. Therefore, EPA is promulgating the
following slightly modified (i.e., clarified) definition of
antique aircraft:
Antique aerospace vehicle or component means an
aircraft or component thereof that was built at least
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30 years ago. An antique aerospace vehicle would not
routinely be in commercial or military service in the
capacity for which it was designed.
Comment; Commenter VI-B-52 stated that in the definition of
cleaning solvent, the parenthetical reference to water or acetone
is confusing and should be deleted.
Response: The Agency agrees with the suggested change and
has removed the parenthetical statement in the amended rule.
Comment: Commenter VI-B-52 noted that in the definition of
chemical milling maskant, listed examples should be made
identical to the listed names for these maskants found in
appendix A to subpart GG.
Response: The Agency agrees with the commenter. The
amended rule contains this language.
Comment; ' Commenter VI-B-63 stated that the Agency should
revise the definition of "aerospace facility" to reflect what the
commenter stated as their interpretation of what Congress
intended for MACT to only apply to the confines of the set of
activities that make up the MACT category, not at those sources
that were "major" through an accumulation of unrelated emissions.
Response; The Agency believes that this comment was
appropriately addressed in the response to comments for the
promulgated NESHAP and refers the commenter to section 3.1 of the
National Emission Standard for Hazardous Air Pollutants for the
Aerospace Manufacturing and Rework Industry - Background
Information for Promulgated Standards, July 1995, (Document
No. EPA/R-97-003b) which contains the comment summary for the
promulgated rule.
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Comment: Commenter VI-B-63 stated that the definition for
chemical milling maskant should exempt chemical milling maskants
used for two different types of chemical milling applications.
The commenter recommended deleting the wording that limits the
exemption to an individual part or subassembly: "...muot be uacd
on an individual part or oubaaocmbly with..."
Response: The EPA did not find any reference to this issue
when maskants were discussed in the section 114 responses or
during any of the roundtable meetings. However, the EPA did not
intend to create an extra burden for existing plating shops using
the same maskant tanks for two different types of chemical
milling applications. The proposed definition and associated
maskant limits would require the addition of a new maskant tank
to meet the low VOC maskant limit and another tank to meet the
critical use applications. This may result in an increase in
emissions since the surface area of the maskant in the tanks
''would double. The EPA agreed that the commenter's changes are
reasonable because the purpose of the NESHAP is to reduce HAP
emissions. The final rule amendments have incorporated this
change to the definition of chemical milling maskant.
Comment: Commenter VI-B-63 suggested changing the flush
cleaning definition in § 63.742 by adding "Cleaning operations in
a tank or vat subject to other NESHAP are not included." Tank
cleaning operations are covered in other NESHAP such as the
Halogenated Solvent Cleaning NESHAP and should be specifically
excluded from the aerospace NESHAP.
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Response; The EPA reviewed the definitions and requirements
•associated with the Halogenated Solvent Cleaning (vapor
degreasing) NESHAP (59 FR 61801, December 2, 1994). Based on
this review and discussions with project work assignment manager,
there is little chance of any overlap with the aerospace flush
cleaning definition or requirements. No changes were made to the
definition of "flush cleaning."
Comment: Commenter VI-B-63 suggested changing the
definition of "self-priming topcoat" by removing the last
sentence which currently reads: "The coating io not aubocqucntly
topcoatod with any other product formulation." The commenter
described two scenarios where the application of such coatings
would not fit the definition. The commenter further stated that
self-priming topcoats should be recognized as topcoats and the
topcoat VOC/HAP limits should apply, not the primer limits.
Response; Self-priming topcoats are recognized as a type of
topcoat with a VOC/HAP limit of 420 g/L -- same as the limit for
topcoats in the NESHAP and CTG. The Agency does not agree that
the described scenarios are likely to present any problems for
facility owners and/or operators or enforcement personnel to
determine the appropriate coating category and applicable limit.
However, the Agency does agree that removing the suggested
wording will clarify the definition of self-priming topcoat and
make it more consistent with the definition of topcoat.
Furthermore, since the limit for topcoats is identical to the
limit for self-priming topcoats, there is no impact to the user
or the environment.
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Comment: Commenter VI-B-63 stated that the definition of
"spot stripping" relies upon the term "technical feasibility"
which is vague and must be assessed on a case-by-case basis. The
commenter added that the U.S. Department of Defense has rewritten
the definition to avoid the need to rely on this elusive concept.
This definition allows the 50 gallons for military aircraft to be
used where required and avoid the murkiness of the technical
feasibility definition approach when applied to spot stripping."
"Spot stripping means the depainting of an area where it is
not technically feasible to use a nonchemical depainting
technique on an aerospace vehicle subject to a limit of
26 gallons of chemical stripper for commercial aircraft and
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50 gallons for military aircraft based on the number of
vehicles serviced per year."
Response: The Agency disagrees with the commenter that the
definition of "spot stripping" is unnecessarily vague. The
Agency believes that the inclusion of the application limits in
the definition does not add clarity to the regulation but would
require the regulated community to search in multiple locations
for the limits found in these standards. The Agency elects to
maintain the existing definition of "spot stripping" contained in
the final rule.
^2.4 DEPAINTING/CHEMICAL STRIPPING
Comment: Commenter VI-B-50 questioned if an entire aircraft
could be stripped with methylene chloride if the spot stripping
limits are not exceeded.
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Response: By definition in the final aerospace NESHAP, spot
.stripping means the depainting of an area where it is hot
technically feasible to use a nonchemical depainting technique.
Depainting information provided by all segments of the aerospace
industry has shown that this typically only occurs on a few areas
(e.g., edges or recessed areas) of each airplane. Those areas can
then be stripped with methylene chloride or any other stripper
(up to the allowable annual limit per airplane). Therefore,
there are no currently known situations where the entire aircraft
could be stripped with methylene chloride (or any other HAP-
containing chemical stripper) at a facility subject to the
aerospace NESHAP without violating the NESHAP requirements.
Comment: Commenter VI-B-50 requested clarification between
spot stripping and depainting operations.
Response: By definition in the final aerospace NESHAP:
"depainting" means the removal of a permanent coating from the
outer surface of an aerospace vehicle or component, whether by
chemical or nonchemical means. For nonchemical means, this
definition excludes hand and mechanical sanding, and any other
nonchemical removal processes that do not involve blast media or
other mechanisms that would result in airborne particle movement
at high velocity; and "spot" stripping means the depainting of an
area where it is not technically feasible to use a nonchemical
depainting technique.
Comment; Commenter VI-B-50 questioned if regulations
promulgated by the U.S. Federal Aviation Administration (FAA)
would take precedence over the aerospace NESHAP.
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Response: The EPA and FAA both recognize that there is a
potential for conflict involving regulations concerning the use
of HAP-containing chemical strippers. Many of the aircraft
manufacturers have made the necessary revisions to their
maintenance manuals to allow non-HAP materials to be used for
depainting (chemical strippers). Once the necessary information
regarding alternate/compliant chemical strippers is approved and
distributed to the regulated community via revised/updated
maintenance manuals and/or advisory circulars, the potential
conflict will be eliminated.
Comment: Five commenters (VI-B-52, VI-B-57, VI-B-58,
VI-B-63 and VI-B-66) raised issues related to the spot stripping
-f:« , • ' '
and decal removal allowance. Two commenters (VI-B-52 and VI-B-57)
-noted that after a preliminary review of chemical strippers used
'" by the industry, it was determined that at least 7 out of 10
ft'
qualified strippers used by the industry have densities higher
•*.;•." - • }
v than the density apparently used by EPA to arrive at the proposed
190 and 365 pounds. Methylene chloride, which (the commenter
understood) EPA was intending to allow for use in spot stripping
and decal removal, also has a higher density. Therefore, the
proposed 190/365 pounds is more restrictive than the original
26/50 gallons previously allowed in the final rule. The
.; commenter does not believe the proposed change will provide more
''" flexibility as stated in the preamble.
Commenter VI-B-63 stated that the proposed change in
v§ 63.746(b)(3) of the amendments potentially reduces the amount
of stripper allowed to be used per military aircraft per year.
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The final rule allowed for the use of 50 gallons of organic HAP
containing stripper per military aircraft depainted per year.
The proposed limit allows for only 365 pounds of organic HAP
material per military aircraft depainted per year. One stripper
used for depainting has a specific gravity of 1.19 and an organic
HAP content of 84 percent. For 50 gallons of stripper, this
calculates to 417 pounds of HAP material. Different types of
strippers are used for different applications, based on the type
of coating which is -being removed. The various types of
strippers have different percentages of HAP constituents.
Allowances need to be made for the use of the appropriate
stripper for the job. The commenter prefers the 50 gallons limit
versus the limit expressed in pounds. If the limit is expressed
in pounds, then it should be 420 pounds (based on specific
gravity calculations).
Commenter VI-B-52 stated that based on the discussion in the
BID (July 1995) regarding facilities using 26/50 gallons of HAP-
containing stripper per aircraft, there is some confusion over
the NESHAP language and the terms of the exemption -- volume of
organic HAP-containing chemical strippers per aircraft and not
per facility.
Commenter VI-B-57 stated that the proposed amendments do not
make it clear that the mass limit on HAP containing chemical
stripping agents is based on the amount of HAP, not HAP-
containing compounds. It would be clearer if the word
"material(s)" is removed from each weight limit.
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Commenter VI-B-58 stated that the decal removal exemption
for commercial aircraft of 26 gpy is based on the amount of
stripper required for the spot stripping and decal removing on
the largest commercial aircraft. The same exemption is available
for depainting general aviation aircraft which are, at most, half
the size of a commercial aircraft. Therefore, even the existing
regulation allows facilities to use approximately twice the
amount of stripper needed to spot strip and remove decals from
general aviation aircraft.
This commenter stated that the proposed revisions to this
rule would expand this exemption considerably. Three strippers
currently used in industry contain 178, 167, and 123 pounds of
HAP per 26 gallons of stripper respectively, 12 to 67 pounds less
than the 190 pounds proposed by EPA. Assuming that 13,000
••• general aviation aircraft are depainted each year, an increase in
methylene chloride emissions of 12 to 67 pounds per aircraft
& '-
would result in a total yearly increase in methylene chloride
emissions between 156,000 pounds and 871,000 pounds. The
commenter encouraged EPA to abandon the proposed revision to the
depainting exemption. However, if EPA does revise the depainting
exemption, it should reduce the allowance for general aviation
aircraft depainting operations to the "lowest amount necessary".
Commenter VI-B-66 stated that the proposed amendments would
revise the limits for use of materials containing HAP for spot
stripping and decal removal from gallons of stripper per aircraft
to pounds of HAP. The commenter agrees that this change will
provide greater flexibility to owners and operators in selecting
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materials for difficult stripping operations. The commenter
further believes that this change will promote innovation in the
development of effective stripping formulations.
Response; Various commenters have presented their views on
this proposed change in different ways, depending on their
perspective and interests. The depainting requirements are to be
met facility wide and the spot stripping allowance is an annual
average (per aircraft) limit the facility must also comply with.
With regards to the -emission estimates provided by commenter
VI-B-58, the EPA does not believe many (e.g., less than
10 percent) general aviation aircraft are reworked/depainted at
major source facilities subject to the NESHAP requirements. The
promulgated standard included the spot stripping and decal
removal allowance using terms of volume (gallons) of organic HAP-
containing chemical strippers. The proposed allowance was meant
to be equivalent in terms of actual HAP emissions to the
atmosphere and was based on assumptions documented in the BID
and/or the docket concerning average or typical HAP contents and
densities of chemical strippers being used by the aerospace
industry. The proposed limits also provide greater flexibility
to the owner or operator of a new or existing depainting
operation in selecting materials to perform spot stripping and
decal removal.
Based on the submitted comments and the technical arguments
both for and against the different units for the spot stripping
and decal removal allowance, the EPA decided to include both
types of units and allow sources to decide which units they want
to use and document their decision in their initial notification
and/or operating permit application. The EPA agrees with the
commenter raising the issue/confusion involving the term
"material(s)" and has deleted it in the final amendment text.
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Comment: Two commenters (VI-B-52 and VI-B-61) stated
concern that the existing language could be read to prohibit the
use of this exemption by facilities that do 'not utilize non-SAP
or nonchemical depainting methods. This is inconsistent with
industry's understanding that the exemption was intended to allow
facilities, regardless of any other depainting operations that
may be conducted, to use small quantities of HAP-containing
strippers exclusively for spot stripping and decal removal.
Response; The commenter is correct that the intent of this
exemption is to allow for the limited use of HAP-containing
chemical' strippers for spot stripping or decal removal at any
aerospace manufacturing or rework operation. The Agency has
modified the existing text in § 63.746(b)(3) by deleting the
phrase "complying with paragraph (b)(1)".
Comment: Two commenters (VI-B-57 and IV-B-61) proposed the
following change to § 63.746(a): "This aubpart section does not
apply to an aerospace manufacturing or rework facility that
depaints six or less completed aerospace vehicles in a calendar
year."
Response: The Agency agrees with the commenter. The final
amendments incorporate this language.
Comment: Commenter VI-B-49 noted an apparent error in the
proposed revision of Equation 20. If one follows this equation,
the resulting units for C are not pounds of HAP per aircraft.
Response: The Agency agrees with the commenter. The
numerical values resulting from Equation 20 (as proposed) will be
accurate, however, the units do not cancel correctly. Units are
accurately determined in revised Equation 20 (Equation 21 in the
final amendments) and the definition of Dhi has been revised in
the final amendments.
Comment; Commenter VI-B-49 stated that the proposed
standard for the spot stripping allowance should read "no more
than 365 pounds ...".
Response: The Agency also noted this inconsistency in the
proposed changes to § 63.749(f) (3)(ii)(A) and has corrected the
wording in the final amendments.
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Comment; Commenter VI-B-63 stated that § 63.746(b)(1) of
the final rule and the proposed amendments does not recognize
that many depaint technologies emit small quantities of organic
HAP. The intent of EPA is better achieved by disallowing
materials which contain organic HAP. Users should be able to
rely upon the MSDS as a common set reference to determine
compliance for the purpose of this section of the rule.
Recommendation --> In § 63.746(b)(1), change: "... subject to
this subpart shall emit no not apply materials which contain
organic HAP ... as identified in the MSDS."
Response: The EPA's primary interest in this NESHAP is to
reduce HAP emissions to the atmosphere. While the commenter's
proposed change would result in equivalent (if not slightly
greater) emission reductions, the EPA does not want to prevent
facilities from using control devices if appropriate for specific
applications. Thus, the Agency decided to leave the promulgated
standards for depainting operations as is.
Comment: Commenter VI-B-66 recommended that, in the absence
of more favorable provisions for the depainting of small
corporate aircraft and other general aviation, .the standards be
further revised to allow the use of HAP-based stripper
formulations beyond spot stripping and decal removal for these
smaller aircraft. This change would address the unique
challenges faced,by firms maintaining these aircraft, while
providing significant incentive for reductions in HAP emissions.
Moreover, the change could help to provide a more level "playing
field" for these facilities who must compete with smaller firms
that will not be covered by the standard. Available data suggest
that firms covered by the standard account for only 10 to
20 percent of the companies maintaining general aviation.
Response; This issue goes back to the depainting allowance
for certain types of aircraft and what is reasonable in terms of
an allowance for spot stripping and decal removal. The EPA
developed the 26/50 gallon allowance based on input from the
large commercial rework facilities and the Air Force on their
technical estimates of the relative amount of exterior surfaces
2-14
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of their aircraft requiring spot repair (stripping) and/or decal
removal. Based on the relative exterior surface areas for GA
aircraft, there is no compelling technical argument to expand the
allowance for GA rework facilities into a depainting limit.
2.5 MISCELLANEOUS NESHAP ISSUES
Comment: Commenter VI-B-66 supports EPA's proposal to
establish a VOC and HAP limit of 622 g/L for uncontrolled Type I
maskants, based on information collected as part of a section 114
request. The proposed limit recognizes that some chemical
etching applications require the use of solvent-based maskants,
while still achieving a significant reduction in VOC and HAP
emissions from masking operations.
Response: The Agency appreciates the commenter's support on
this issue.
Comment; .Commenter VI-B-52 stated that in the preamble of
the proposed amendments, Section F. Test Method for Determining
Filtration Efficiency should be clarified so that the filter
efficiency tests may be performed by someone other than the owner
or operator of the source.
Response; Several commenters mentioned this issue in both
the preamble and proposed amendatory language of the regulation.
It was not the Agency's intent to limit who could perform the
filter efficiency tests. The amendatory text has been modified
to clarify this requirement in the final amendments.
Comment: Commenter VI-B-52 stated that under § 63.753, EPA
should clarify that the required semiannual reporting may be
combined with the semiannual reporting requirements of Title V
Operating Permit reports as long as all the required information
is provided.
Response; The Agency understands the related issues to this
specific comment and encourages sources and States to work
together in streamlining reporting requirements. However, it is
not appropriate to necessarily combine requirements within the
regulatory text of the NESHAP.
Comment: Commenter VI-B-57 requested the removal of the
requirements for ozone depleting substances from § 63.744. There
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is no legal basis for including a requirement that hydrocarbon-
based cleaning compounds contain no ozone depleting substances.
The control of HAP and ozone-depleting substances are under two
entirely separate programs with two separate time lines.
Response; The Agency agrees with the commenter and has
deleted the reference to ozone depleting substances in Table 1 of
§ 63.744.
Comment; Commenter VI-B-64 complimented EPA for including a
reasonable de minimis quantity for VOC and HAP containing
products.
Response: The Agency appreciates the comment.
Comment; Two commenters (VI-B-63 and VI-B-66) remarked on
the applicability of the NESHAP cleaning requirements. Commenter
VI-B-63 stated that the NESHAP applies to the use of hand-wipe,
spray gun, and flush cleaning operations conducted in connection
with nonaerospace activities. The aerospace NESHAP cleaning
requirements should only apply to aerospace operations. While
the preamble stated that the NESHAP only applies to aerospace
operations, the rule itself was not changed to make it clear that
this is the application of the rule. Commenter VI-B-66 supported
the proposal to limit the standards for cleaning operations to
the manufacture and rework of aerospace vehicles and components.
Response; This was specifically addressed in the recently
proposed amendments to the rule (see § 63.741(c) on page 55853 in
the October 29, 1996 Federal Register notice) and the final
amendatory language reflects the revised language which is
consistent with that recommended by the first commenter.
Comment: Commenter VI-B-63 did not agree with EPA under
§ 63.744 Cleaning operations: To require bagging or
containerizing of VOC-containing wipe materials will be an
enforcement nightmare for facilities and enforcement agencies.
No matter how you define "immediately after use" there will
always be different interpretations of the term "immediate". The
commenter recommended deleting the wording in § 63.744(a)(1) and
replacing with: "Storage and disposal of all VOC-containing
solvents, used in the cleaning of aerospace vehicles and
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components, shall be in nonabsorbent nonleaking containers, which
shall be kept closed, except when filling or emptying. It is
recommended that cloth and paper moistened with VOC-containing
solvents be stored in closed, nonadsorbent, nonleaking
containers."
Response: This issue was addressed in the recent proposed
amendments and the revised language is more consistent with the
storage requirements in the California SIP-approved rules that
were the basis for this requirement.
Comment: Commenter IV-B-63 stated that not all HAP's are
VOC's, nor are all VOC's HAP's. If the "and" is used, then one
could read § 63.741(f) to require both VOC's and HAP's to be
present for this exemption to be acceptable. The intent was for
the exemption to apply if either HAP, or VOC, or both were
present below the specified concentrations. The commenter
suggested the following de minimis HAP/VOC exemption
clarification: "The requirements of this subpart also do not
apply to primers, topcoats, chemical milling maskants, strippers,
and cleaning solvents containing HAP and/or VOC at a
concentration less than ..."
Response: The Agency does not agree with the commenter on
what was intended for the exemption. It is not the Agency's
position that both HAP and VOC need be present for an exemption
to apply. The Agency believes the term "HAP and /VOC" correctly
identifies those situations where the requirements of this
subpart do not apply. If a cleaning solvent contains VOC at a
concentration above the specified 0.1 percent and HAP at a
concentration below the 0.1 percent, the exemption does not
apply. If the suggested "and/or" were used, the exemption could
be applied to this scenario.
Comment: Commenter VI-B-63 stated that § 63.743(b) of the
final rule restates and strengthens the requirement in the
General Provisions for "maintenance plans." The development of
such a comprehensive plan for particulate filters would represent
an excessive burden to the industry without a commensurate
environmental benefit. Particulate filtering systems are
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generally not prone to start up and shut down malfunctions as
required for the plans. 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. Manufacturers
specifications or some other negotiated method could then be
used. Therefore, in § 63.743(b), add the following: "Startup,
shutdown, and malfunction plan: Plan requirements shall be
delineated in the appropriate Title V operating permit."
Response; The Agency agrees with the commenter in that
particulate filtration systems are not prone to startup/shutdown
problems and addressed this issue in the recently proposed
amendments. Section 63.743(b) states: "Dry particulate filter
systems operated per the manufacturer's instructions are exempt
from a startup, shutdown, and malfunction plan."
Comment: Commenter VI-B-63 stated that
§ 63.745(g)(2)(v)(C)-Continuous monitoring, would require
installation of costly, "real-time" monitoring equipment.
Currently, the commenter is aware of visual "sight glass"
pressure drop indicators on filtration equipment. The commenter
believes that an inspection of all "sight glass" indicators once
each shift would be sufficient to ensure proper equipment
operations. In addition, this is consistent with the pressure
drop requirements identified in § 63.752(d). The commenter
recommends that § 63.745(g)(2)(v)(C) be revised as follows:
change " monitor once per shift the pressure drop across the
filter; and"
Response: The Agency agrees with the commenter's viewpoint
on what is reasonable monitoring to ensure proper equipment
operations and tried to address the general issue of "continuous
monitoring" in the recent amendments (see II.M of the preamble,
page 55851 in the October 29, 1996 Federal Register notice). The
Agency has added text to § 63.745(g)(2)(iv)(C) and (g)(2)(v) to
be consistent with the other recent clarifications such as
§ 63.751(c)(l) involving monitoring requirements.
Comment: Commenter VI-B-63 stated that sources which
commenced construction prior to promulgation of the final rule
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should be allowed to comply with the requirements for existing
sources because, at the time of construction, there was no
proposed or final rule requiring the implementation of 3-stage or
equivalent filters. In the final rule and proposed supplemental
notice, sources which commenced construction between the dates of
the proposed and final rules are required to comply with the
inorganic HAP emission requirements for new sources. The final
rule and the proposed supplemental notice requirements for new
"sources are far more restrictive than those in the proposed rule.
The supplemental notice proposes less restrictive requirements
for sources which commenced construction between the final rule
and the proposed supplemental notice than for those between the
proposed and final rule. Reconstruction of sources which
commenced construction prior to September 1, 1995 should be
required to meet the requirements for existing sources.
Response: This issue was also raised at the March industry
roundtable meeting and was addressed in the recently proposed
amendments to the aerospace NESHAP (see II.K of the proposed
£**
preamble, page 55851 in the Federal Register notice published on
* October 29, 1996). The Agency realizes that there are unique
•if
circumstances in which owners or operators have commenced
* construction or reconstruction of a new spray booth or hangar
after the proposed regulation (June 4, 1994) and have had to
comply with the requirements in the promulgated rule
(September 1, 1995). For these owners or operators of aerospace
manufacturing or rework operations who have commenced
construction or reconstruction of a new spray booth or hangar for
inorganic HAP depainting operations, primer, or topcoat
operations after June 4, 1994 but prior to October 29, 1996, the
EPA has provided the flexibility to meet either the requirements
for new sources under § 63.745(g)(2)(ii) of the amendments to the
final regulation found in today's notice or the requirements for
new sources under § 63.45(g)(iv) of the September 1, 1995
promulgated rule which are found at § 63.745(g)(2)(iii) in the
amended rule. Sources that commended construction prior to
June 4, 1994 are still required to meet the existing source
2-19
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requirements for depainting operations and painting (topcoat or
primer application) operations found in the final amended rule.
Comment; Commenter VI-B-63 stated that Section II.M of the
preamble of the proposed amendments includes alternative
particulate control technologies that demonstrate equal or better
performance at the three sizes specified in the new sources
table. If the other references to filters do not also include
the "equivalent" alternative technologies as part of the
reference, the disconnect could turn into a paperwork trap
anytime a different technology is installed. The commenter
recommends all references to filters allow alternative
particulate control technologies that demonstrate equal or better
performance at the three sizes specified in the new sources
table.
Response: While the Agency agrees with commenter's
assertion that equivalent alternative technologies need to be
allowed and documented within the NESHAP requirements, the Agency
also believes that there are existing mechanisms within the
General Provisions which address this issue. (See alternative
test method definition in 63.2). The owner and/or operator will
need to get the alternative test method approved regardless.
Comment: Commenter VI-B-48 questioned if the effective date
to be considered a new source is September 1, 1995 or when the
aerospace NESHAP first appeared in the Federal Register in June
1994.
Response; The effective date is June 6, 1994.
Comment: Commenter VI-B-48 questioned if converting a
waterwash to a dry particulate filter system would result in the
dry system being considered as a new source for primer and
topcoat application operations.
Response: If the conversion cost more than half of the
fixed capital cost estimated for constructing an entirely new dry
system, then the converted dry system would be considered a new
source for regulatory compliance issues. The NESHAP requirements
in § 63.753(a)(1) refer to the recordkeeping and reporting
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requirements, of the General Provisions, 40 CFR part 63,
subpart A.
Comment; Commenter VI-B-48 questioned'if the reconstruction
of an existing hangar (used for primer and topcoat application
operations) would cause it to be considered a new source upon
completion.
Response: If the primers or topcoats used in the hangar
contain inorganic HAP, then the new or reconstructed spray booth
or hangar will be subject to the applicable new source
requirements for inorganic HAP. New construction or
reconstruction of a new spray booth or hangar at a facility for
an existing coating or depainting operation will not cause the
existing operation to be subject to any other new source
standards.
Comment; Commenter VI-B-48 questioned if reconstruction or
relocation of an existing booth in a facility mean that the booth
would be considered a new source.
Response: If an existing booth is. simply relocated within
the same source (i.e., facility or building), there would be no
regulatory significance. For reconstruction of an existing
booth, see the two previous comments and responses.
Comment: Commenter VI-B-62 concurred with the Agency's
clarification of the applicability section by removing the
reference to space vehicles in § 63.741(f) and adding a new
§ 63.741(h) which states regulated activities associated with
space vehicles are exempt from the requirements of this subpart,
except for depainting operations found in § 63.748. The
commenter stated that this revision reflected an important
clarification of the applicability of the rule for aerospace
organizations.
Response: The Agency appreciates the commenter's
concurrence on this issue. The proposed language has been
revised slightly for greater consistency with the stratospheric
ozone regulations. The exemption was added to the final rule as
§ 63.744(e)(13).
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Comment: Commenter VI-B-62 concurred with the addition of
§ 63.744(e)(13). The commenter noted that this addition
acknowledges critical materials which have been granted Essential
Use Waiver under the CAAA Title VI and the Montreal Protocol, and
recognizes the exemption from the rule for the continued use of
those critical materials.
Response: The Agency appreciates the commenter's
concurrence on this issue.
Comment: Commenter VI-B-53 stated that the Agency should
provide flexibility in the regulation to allow a broader
averaging approach. Specifically, averaging between controlled
and uncontrolled primers, topcoats, and chemical milling maskants
should be allowed.
Response: This issue was raised.previously and EPA tried to
evaluate the impacts of various averaging schemes and develop a
compliance strategy that incorporated averaging across emission
points. Unfortunately, a workable solution to this overall issue
of allowing a broader averaging approach was never developed.
In designing emissions trading and averaging systems, EPA
believes that it is important to consider the effect that trading
or averaging is likely to have on facilities' actual emissions,,
as well as the effect on facilities' maximum allowable emissions.
A workable scheme for averaging across coating types was not
developed because the format of the coating limits in the rule as
originally promulgated (September 1, 1995) creates inherent
difficulties for making accurate and equitable emissions
comparisons. In order to include effective emissions averaging
provisions for different coating categories (i.e., primers,
topcoats, and maskants) or other emission sources, the format of
the entire rule would have to be overhauled. Such changes are
now beyond the scope of the work involved in finalizing the
amendments to the aerospace rule and cannot be justified in terms
of potential advantages to industry (e.g., affected facilities)
and/or the environment.
Comment: Commenter VI-B-63 stated in § 63.750'(I) (2) (i) ,
alternative application methods of primers or topcoats should be
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allowed where manufacturers have demonstrated equivalency with
HVLP/electrostatic transfer efficiency. This process of 30-day
period using HVLP and then using alternative method for same time
and process is not appropriate. If a manufacturer is able to
demonstrate new technology equivalent to HVLP, it must be
available to users without long, drawn out testing. Only where
users are developing their own technology should this detailed
testing be required. Recommendation: Change evaluation period
"from 30 to 4 days.
Response: Any time period specified in the evaluation of
alternative equipment or test methods is certainly subjective to
the amount of actual, painting that is done. For large
facilities, coating operations are typically conducted every day
and in many cases, around-the-clock. However, for many of the
smaller facilities and particularly rework facilities, coating
: operations may only be conducted one or two shifts per week. The
EPA decided that 30 days is a reasonable compromise for all types
and sizes of facilities to demonstrate equivalency and also
* provided additional flexibility.for qualifying other application
. methods. In the final rule; § 63.750 (i) (2) (i) states "For the
* process or processes for which the alternative application method
"t is to be used, the total organic 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."
Based on other comments related to this section of the final
rule, the EPA has provided additional flexibility for those
sources wanting.to use an alternative application method from
primers and topcoats by adding (revising) paragraphs
-• § 63.750 (i) (2) (iii) and (iv) as follows:
(iii) Test the proposed application method against either
•*•• HVLP or electrostatic spray application methods 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 laboratory test will use the same part configuration(s) and
2-23
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the same number of parts for both the proposed method and the
HVLP or electrostatic spray application methods.
""" (iv) Whenever the approach in either paragraph (i)(2)(ii)
or (i)(2)(iii) is used, the owner or operator shall calculate
both the organic HAP and VOC emission reduction using
equation 19.
2.6 NOT RELEVANT TO PROPOSED AMENDMENTS
Comment: Commenter VI-B-52 referenced § 63.744(e) and the
CTG stating the EPA should modify the cleaning operations
requirements to include an exemption from the need for a closed
container when "cleaning the nozzle tips of automated spray
equipment systems, except for robotic systems." In Rule 1171-
Solvent Cleaning Operations, the South Coast Air Quality
Management District (SCAQMD) has included an exemption from the
need for a closed container when "cleaning of the nozzle tips of
automated spray equipment systems, except for robotic systems."
This exemption was added because automated spray equipment cannot
be easily assembled, and these guns may occasionally need to be
quickly cleared of paint residue with a minimum disruption of
production. Being able to quickly spray solvent through-the gun,
which will solve the operating problem, has thus been allowed by
the SCAQMD. A similar exemption should be included in this
section of the NESHAP.
Automated spray equipment is not generally programmable,
i.e., it is typically set up on a moving track to spray when a
part is positioned in front of it and to shut off when no part is
sensed. A robotic system, on the other hand, can be programmed
to move away from the parts to spray cleaning solvent into some
type of closed container. The "dumb" automatic reciprocator has
no such capability, since it is rigidly fixed to its support
structure. When such a gun needs to be cleaned, without being
dissembled, it can only spray solvent into the open air of the
booth. Thus, this simpler type of automated automatic equipment
needs an exemption from atomized open air spraying, unlike a
fully robotic system which can be positioned to spray into a
nearby closed container.
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Response: The commenter referenced SCAQMD Rule 1171 as
having recently including this exempt-ion in their rule. Having
reviewed the most recent version of Rule 1171, the EPA agrees
with the commenter and will propose the change in the next
supplemental notice to the NESHAP.
Comment: Two commenters (VI-B-52 and VI-B-63) raised the
issue of pumpless waterwash systems, stating the EPA had been
previously petitioned to modify the waterwash particulate control
system requirements to allow for use of existing waterwash
systems which do not utilize flowing water (a pumpless system) to
,remove particulate emissions from the exhaust air stream in spray
coating application or dry media blast depainting operations. To
accomplish this, several areas of the rule should be changed:
§§ 63.742, 63.745(g) (2) (v) , 63.751(c)(2),'63.751(d), 63.752(d)(2)
and (3), and 63.752(e) (7) .
Response: This comment was included in the comments made
after the original rule was proposed -- see BID II, page 7-43.
The response at the time was "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."
In followup discussions with the commenters, the EPA has
learned that there are at least two types of pumpless waterwash
systems currently being used by aerospace facilities. There is
no readily identifiable operating parameter that is common to
both types of systems. Therefore, the EPA decided to use the
generic approach as suggested by one of the commenters and will
propose the change(s) in the next supplemental notice to the
NESHAP.
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Comment: Two commenters (VI-B-60 and VI-B-65) stated
§ 63.750(g)(1) uses the term "dedicated solvent recovery device",
but it is not defined in the rule. The EPA needs to define this
term so the owner or operator and any enforcement agency know
what a dedicated solvent recovery device is so that proper test
procedures may be followed and proper enforcement of this aspect
of the rule accomplished.
Response; The Agency has included the following definition
(based on the definition from the Hazardous Organic NESHAP or
HON) for "recovery device" in the amendments to the final
aerospace rule:
Recovery device means an individual unit of equipment
capable of and normally used for the purpose of recovering
chemicals for fuel value, use, or reuse. Examples of
equipment that may be recovery devices include absorbers,
carbon adsorbers, condensers, oil-water separators, or
organic-water separators or organic removal devices such as
decanters, strippers, or thin-film evaporation units.
A dedicated solvent recovery device refers to such control
equipment (as described/defined above) that is specific to ,a
given process or control system.
Comment: Two commenters (VI-B-60 and VI-B-65) stated
§ 63.753(c)(iv)(A) indicates that if a carbon adsorber is used,
each owner or operator shall indicate each rolling period when
the overall control efficiency of the control system is
calculated to be less than 81 percent, the initial material
balance calculation, and any exceedances as demonstrated through
the calculation. However, only part (g)(1) of the "Test methods
and procedures" section requires a material balance to be
accomplished over a 7- to 30-day period. The remaining parts of
(g) where a carbon adsorber may be used [parts (2) through (6)]
appear only to require that the capture and control efficiency of
the carbon adsorber be equal or greater than the 81 percent, with
no material balance or any rolling period involved. The EPA
needs to clarify this apparent inconsistency in requirements of
when a material balance and a "rolling period" are needed.
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Response; The EPA went back and reviewed the various
reporting requirements associated with control devices. Having
done this, the Agency does not agree•.with the comraenter that the
reporting requirements should be consistent regardless of the
compliance approach. Not all compliance approaches lend
themselves to rolling averages and not all control/monitoring
equipment provide the same types of data. In fact,
§ 63.749(g)(1) includes language that allows sources to use a
'" liquid-liquid HAP or VOC material balance over 7- to 30-day
periods in lieu of demonstrating compliance using the methods in
§ 63.749 (g) (2) , (3) , or (4) .
Comment: Two commenters (VI-B-57 and VI-B-61) stated that
the reference to section 112(1) of the Clean Air Act noted in
§ 63.744(b)(3) -- Alternative volume reduction demonstration for
hand-wipe solvents, appears to be misplaced. Requiring approval
of each individual plan to undergo the complicated approval
procedures of 112(1) is unwarranted and contrary to the intent of
112(1). Additionally, the EPA should delete the requirement for
demonstrating that the 60 percent volume reduction provides
emission reductions equivalent to the solvent composition or
vapor pressure compliance options. It would be impossible for a
^ facility to make such a demonstration. In promulgating the
60 percent reduction standard, EPA has already established a
level of reduction that is equivalent to the other options.
Response; With regards to the cited reference to
section 112(1), the Agency agrees with the commenters and is
proposing amendatory language to remove all references to
section 112(1). The Agency agrees with the commenters in that
the language describing how the equivalency is to be demonstrated
* is confusing. Therefore, the proposed amendments to the final
rule includes new language stating "The baseline shall be
"* calculated using data from 1996 and 1997, or as otherwise agreed
upon by the Administrator or delegated State Authority."
Comment: Commenter VI-B-57 stated that the references made
to SIC codes do not include SIC code 4512: Scheduled Air
Transportation. Because most airlines operate under this SIC
2-27
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code, the commenter recommended its inclusion in the list of
example SIC codes.
Response: This is not a regulatory issue, but will be taken
into account in those informational documents describing the
affected industry. Table 1 in the preamble to the final rule
included a listing of affected SIC codes and will also be revised
accordingly. As of January 1, 1997, a new numerical coding
system for classifying industries has been implemented by the
U.S. Census Bureau. The new system is called the North American
Industrial Classification System (NAICS). The NAICS codes have
up to six digits whereas the SIC codes are four digits. This
allows the ability to group industries into more sectors while
allowing the identification of more industry types. The table on
the following page summarizes/cross-references the SIC and NAICS
codes likely to be affected by the aerospace NESHAP.
Comment: Two commenters (VI-B-57 and VI-B-61) offered
comments on the exemption for hand-held spray can applications in
§ 63.745(g)(4). Even though there is an exemption for hand-held
spray can applications for topcoats and primers-: However, there
is no similar exemption for control of inorganic HAP emissions.
Though hand-held spray cans used outside a paint booth or hangar
would typically be exempt in any event for touchup operations, a
specific spray can exemption is needed for purposes of clarity
and to avoid confusion.
Response: The exemption for hand-held spray can
applications was inserted under section 63.745(f) (3) (v) based on
comments to the original (June 1994) proposed rule stating only
small emission reductions would result from their regulation and
that such applications are already exempt under SCAQMD Rule 1124.
The hand-held spray can exemption could be perceived as
unnecessarily restrictive to only address organic HAP emissions.
The Agency agrees that the exemption should also be applicable to
inorganic HAP emissions and added an exemption for the use of
hand-held application methods under 63.745(g)(4)(x).
Comment: Two commenters (VI-B-57 and VI-B-61) noted there
should be a reference to the term "H.^" in § 63.750 (k) since
2-28
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Response: The Agency agrees with the commenter and has
revised § 63.750(k) to read as follows: "... determine the mass
of organic HAP emitted per unit volume of coating (chemical
milling maskant) i as applied (less water), H± (Ib/gal)." This
clarification is included in the final amendments to the NESHAP.
Comment: Commenter VI-B-53 stated that the Agency should
allow for alternative methods for monitoring/recordkeeping/
reporting (MRR) as long as equivalent public health protection
can be demonstrated.
Response: The EPA agrees with the commenter. Table 1 to
Subpart GG incorporates by reference the applicable sections of
the General Provisions Subpart A. This includes the relevant
sections of 63.8(f), Use of an Alternative Monitoring Method, and
63.10(f), Waiver of Recordkeeping and Reporting Requirements.
Both of these sections contained within the General Provisions
allow the source to request an alternative(s) and specify the
conditions that source must meet for approval of any
alternative(s) by the Administrator (or a delegated state).
Comment: Commenter VI-B-63 recommended that under § 63.741
Applicability: To extend MACT controls to those sources that
were "major" through the accumulation of unrelated emissions is
unjustified on policy grounds. Therefore, it is recommended that
the definition of "affected source" be changed to reflect only
aerospace facilities that are major sources.
Response: In general, the Agency disagrees with the
commenter and refers the commenter to the July 21, 1995 D.C.
Circuit Court decision, National Mining Association, vs. U.S.
Environmental Protection Agency, where the NMA challenged EPA's
definition of major sources. The Court's decision reaffirmed
EPA's implementation of the definition of major source which
requires the aggregation of all hazardous air emissions within a
plant site.
However, the Agency has provided guidance on the
implementation of Section 112 standards with regard to major
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source determinations at Federal military installations (see the
letter from John Seitz to the EPA Regional Air Director, dated
August 2, 1996). In summary, this guidance allows for case-
specific determinations regarding common control for separate
military entities at the same military installation.
Comment: Commenter VI-B-63 requested military operations be
exempted from NESHAP requirements during hostilities or war, or
when national security is an issue.
Response: The EPA does not believe there is any technical
" justification for including such an exemption for the
applicability of the final rule. Section 112(i)(4) of the Clean
Air Act contains a "Presidential Exemption," which allows the
President to exempt any source from compliance with a NESHAP for
a period of up to 2 years if the President determines that the
technology to implement the standard is not available and that
the exemption is in the national security interests of the U.S.
This provision would likely be broadly construed to allow the
President to respond to emergencies such as war or national
security issues. Because this exemption is provided by statute,
there is no need to write an exemption into the text of the
regulation.
" Comment; Commenter VI-B-63 requested the definition of •
"aerospace vehicle or component" be revised to exclude purely
military components such as weapon systems, military surveillance
equipment, guns, etc.
Response: The EPA does not believe there is any technical
justification for the suggested revision.
Comment; Commenter VI-B-63 recommended adding the following
definition: "Critical to flight performance means those portions
of the aircraft that are needed to fly the aircraft (e.g., wings,
fuel tanks, cockpit)" because the term is used in the final rule
and a definition is needed; otherwise it is too ambiguous.
Response: The EPA does not believe there is any technical
justification for adding this new term to the definitions list.
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Comment: Commenter VI-B-63 recommended adding the following
definition for military aircraft: "Military aircraft means an
aircraft produced under a Department of Defense (DoD) contract."
Response; The EPA does not believe there is any technical
justification for adding this new term to the definitions list.
Comment; Commenter VI-B-63 recommended revising the
definition for "nonchemical based depainting equipment" by adding
the following clarification (see underlined text):
Nonchemical 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 liquid or paste chemical
stripper. This definition does not include mechanical
sanding or hand-sanding.
The commenter stated their proposed language provides the
technically proper distinction between the liquid or paste
chemical strippers and those (e.g., CC>2, Si.C>2, acrylic,
polyester) which work in a mechanical way.
Response: The EPA does not believe there is any technical
justification for revising the existing definition for
"nonchemical based depainting equipment" to provide the .
technically proper distinction between mechanical and chemical
strippers. The Agency believes such a distinction is implicitly
understood within the context of the existing definition.
Comment; Commenter VI-B-63 recommended changing the third
sentence of the existing definition of "primer" to read as
follows: "Inorganic coatings and coating that are defined as
specialty coatings are not included under this definition." The
commenter stated that inorganic coatings are not covered under
this regulation and the current definition for primer also
describes conversion coatings.
Response; Because NESHAP include both organic and inorganic
HAP and some primers contain both types of HAP,. the Agency does
not think there is sufficient technical justification to modify
the existing definition. All of the specialty coating
definitions were developed with input from industry
representatives attending the roundtable meetings.
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Comment: Commenter VI-B-63 recommended adding a provision
to allow the aerospace NESHAP to evolve and remain valid as new
materials, techniques, and technologies are introduced into the
aerospace industry. Therefore, in § 63.743(e), add the
following: "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 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."
Response: This issue is not specific to the aerospace
NESHAP or any other NESHAP for that matter. Accordingly, § 63.6
(General Provisions) provides regulatory guidance on this issue.
Comment: Commenter VI-B-63 stated that residue or
contamination in potential leak path areas described in
' § 63.743(e)(2) could also result in catastrophic system failure.
*' Therefore, add the words "including surfaces which are .potential
leak paths" at the end of § 63.744 (e) (2) .
Response; The Agency tried to follow-up on this issue with
the listed contact person identified by the commenter. The
Agency did not receive any additional information or technical
justification (explanation) in response to its request for
clarification of this issue. Since data/information are not
presently available to serve as a basis for amending the final
regulation, the EPA has decided to maintain the existing text for
the listed exempt cleaning operations.
Comment; Commenter VI-B-63 stated that in § 63.744(b)(2) of
' the final rule, the term "composite vapor pressure" is incorrect.
"The formula in § 63.750(b) very definitely calculates a partial
vapor pressure of organic VOC's. "It does not calculate a total
vapor pressure of the composite mixture. A statement of
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applicability should have been inserted. The NESHAP should
clearly state that the vapor pressure requirement of 45 mm Hg is
a calculated, hypothetical, ideal mixture value of a true single
phase ideal solution that represents only the VOC components and
it is not a true vapor pressure value. Furthermore, it should
state that it is not valid for emulsions, multi-phase solvent
mixtures, and solvents that have more than 5 percent
nonvolatiles. Recommendation --> In § 63.744(b)(2), change:
"Have a compooito 'partial vapor pressure of 45 mm Hg ..."
Response; While the Agency agrees with the commenter's
technical argument, we believe the term is understood in terms of
demonstrating compliance with the NESHAP requirements.
Comment: Commenter VI-B-63 recommended changing
§ 63.744(e)(11) to read as follows: "Cleaning and solvent usage
associated with research and development, quality control,
production testing, and laboratory testing."
Response: Production testing can result in significant
emissions if the test cycle involves large scale operations.
Therefore, the Agency does not agree with the recommended change
to the existing exemption for cleaning and solvent usage.
Comment: Commenter VI-B-63 stated the listed compliance
method in § 63.745 of the final rule is to comply with the
standard and this does not make sense. The methods used to
comply with § 63.747(e) also need to be further defined.
Response; The Agency does not agree; the listed compliance
methods in § 63.745(e) are directly related to the specified
coating limits and there are multiple compliance options that may
be utilized to meet the limits or control system requirements.
Similarly, the listed compliance methods in § 63.747 (e) are
directly related to the specified chemical milling maskant limits
that were developed as part of the MACT floor and there are
multiple compliance options that may be utilized to meet the
limits or control system requirements.
Comment: Commenter VI-B-63 stated § 63.745(g)(2) of the
final rule requires the owner or operator to shut down the
operation if the pressure drop is outside the limit(s) specified
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by the manufacturer. The commenter believed the immediate shut
down requirement is too severe and that the language should be
softened to require shut down only if repair operations can-not
be accomplished within 24 hours. This would allow the current
application procedure to be completed thereby avoiding the need
to depaint and repaint due to the shutdown in the middle of an
application. The commenter recommended changing the first
sentence in § 63.745(g)(3), to read: "... shut down the operation
immediately after the aircraft undergoing the painting operation
'is complete and take corrective action."
Response: The requirement to shut down the painting process
immediately if the spray booth controls are not working properly
is not unreasonable if you consider the relative amount of HAP
emissions that could be emitted from spray coating operations.
The Agency recommends that the commenter read § 63.6 in
developing their own corrective action response as part of their
facility (source) specific operation and maintenance plan.
Comment: Commenter VI-B-63 referenced § 63.750(a)
composition and (b) vapor pressure determination in describing
several existing and potential problems in trying to get vapor
pressure and average molecular weight data for petroleum based
hydrocarbons or cleaning 'solvents that have a refined petroleum
cut component. The commenter detailed several example scenarios
where problems are likely to develop in trying to obtain accurate
information on hydrocarbon content of cleaning solvents. The
commenter recommended the following changes in § 63.750 (a): 'File-
data ohall identify all componcnto of the cleaning aolvont and
shall demonstrate that one of the approved compbaition
dofinitiono ia mot. In § 63.750(b), eliminate the marked
sentence in paragraph 2: ...using manufacturer's supplied data—©*1
a gaa chromatographic analyaia in accordance with ASTM E 2GO 01
(incorporated by reference as apocificd in § 63.14 of oubpart A
of thio part)—and by...
Response: The commenter's argument is not compelling enough
to justify changing the NESHAP requirements. Several of the
industry suppliers and end-users attended and participated in the
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aerospace roundtable meetings and were integral contributors and
reviewers of the requirements in the final rule. Knowing this,
along with no other comments raised on this issue, leads the EPA
to believe that aerospace facilities and their cleaning solvent
suppliers have resolved (or are working on resolving) this-issue.
Comment: Commenter VI-B-63 asked why § 63.752(b)(4)
requires monthly cleaning solvent usage records at each operation
and a list of the processes for the several exempt cleaning
operations. The commenter stated such requirements are wasteful
and serve no practical utility or benefit to the environment and
recommended it be deleted.
Response: The Agency included the recordkeeping
requirements to provide enforcement officials with some
information on the relative amounts of these cleaning solvents
used in the various exempt cleaning operations. With several
process steps and types of cleaning operations exempted, it would
be very easy for a facility to include nonexempt cleaning
operations and use nonapproved/noncompliant cleaning solvents.
This issue was also raised in comments to the original
proposed NESHAP (June 6, 1994) and the EPA changed the
recordkeeping requirements from daily to monthly in response to
those comments (see 13.6.1 in BID Volume II). The issue of
"practical enforceability" for such recordkeeping requirements
was based on the best information available at the time.
Comment: Commenter VI-B-63 stated the listing of aircraft
parts in § 63.752(e)(4) and the listing of aircraft parts removed
prior to depainting in § 63.753(d)(1)(viii) do not, in any way,
enhance the environmental recordkeeping requirements. Parts may
be removed from an aircraft at one location and then shipped to
another for repair. If EPA decides to keep these requirements, a
few issues need to be addressed. First, how do we handle
variations of the same model? Do we need a list for each sub
model? The second issue concerns low volume aircraft. Do you
want a list kept for sister service plans? These requirements
are labor intensive for little or no gain. The commenter
recommended deleting these requirements.
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Response; The Agency included the recordkeeping
requirements to provide enforcement officials with some
information on the relative number of parts removed from each
type of aircraft prior to depainting operations. The final rule
states that this listing requirement applies to each type of
aircraft, not each individual aircraft. For most facilities,
this minimizes the paperwork burden significantly. As to the
commenter's issue of sub models, the Agency's interest is in
depainting operations and emissions. If the same parts,
subassemblies, and assemblies are normally removed for all
aircraft with the same model number, a single listing for that
"type" of aircraft would be sufficient. The commenter's second
issue concerning low volume aircraft is specifically addressed in
§ 63.752(e) (4) which states: "Prototype, test model or aircraft
that exist in low numbers (i.e., less than 25 aircraft of any one
type) are exempt from this requirement."
This issue was also raised in comments to the original
proposed NESHAP (June 6, 1994) and the EPA continues to believe
that monthly records are a reasonable requirement for practical
enforceability (see 13.8 in BID Volume II) of the NESHAP.
Comment; Commenter VI-B-63 asked about EPA's intention on
the "reduction of monitoring data" in § 63.751(f). Is the intent
that raw data need not be recorded, even when the raw data are
used to determine a "reduced" parameter which is required to be
recorded? As specified in § 63.751(f)(2), all emission data has
to be converted into units specified in the NESHAP for reporting
purposes.
Response; Common sense should apply. If the raw data are
used to determine the parameter to be recorded, there should be
some documented supporting data for those person(s) reviewing
and/or approving the information to determine if the parameter
was determined/calculated properly.
Comment; Commenter VI-B-63 raised several concerns with
"application problems" stating the NESHAP application
requirements are ambiguous and create several uncertainties as to
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which NESHAP is relevant to specific shop functions. The
following example needs clarification:
-- aerosol can (or pump spray container) application of a
volatile "cleaning solvent" under pressure. There are several
issues to be considered in determining how/if/which standard is
applicable. The commenter also provided additional details
involving other examples using different parts that the cleaning
solvent is applied to.
Response: The EPA spent significant time and resources
developing an emission standard which it believes to be
enforceable. Numerous State and local regulatory agencies were
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. Specific
questions on application issues such as the ones raised by the
commenter should be taken up with the appropriate region or
delegated State authority.
Comment: Commenter VI-B-63 asked what constitutes
equivalent emission control? .Consider a.situation.where.a base
used a small ultrasonic cleaning tank (five gallons) containing
cleaning solvent to clean aircraft instrument parts. Does
§ 63.744(d) require the base to pour in five gallons of solvent,
turn on the ultrasonics, wait a half hour to degas, clean the
part for three minutes, and then pour it all back into a closed
can? Consider all the solvent lost in the pouring back and
forth. If the base has a lid on the tank, is this "equivalent
emission control?"
Maybe the approach should be to target total emissions from
any cleaning tank or cleaning line (machine or manual). Losses
from either evaporation or drag-out should be the target. Vapor
pressure limits provide significant controls on evaporation, only
if the unevaporated portion does not enter the environment.
Drag-out or carry-over of cleaner enters the environment either
in a rinse waste stream, evaporation from the rinse process (if a
hot rinse), or just plain evaporation from the part. The loss
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from the latter is fixed by the carry-over, not the vapor
pressure.
Response: The Agency does not agree that the described
situation (i.e., solvent cleaning process) would be subject to
the flush cleaning requirements in § 63.744(d). Such operations
are more likely to be covered under the degreasing NESHAP.
Comment: Comtnenter VI-B-63 stated many cleaning solvent
manufacturers refuse to give information on the exact components
~of their proprietary products. These components can have a
" substantial effect on the vapor pressure of component solvents
which is not reflected in the formula. Section 63.750(a)
requires detailed composition reporting, but does not provide a
de minimis reporting level.
Response: De minimis levels on the HAP content of cleaning
solvents were included in the proposed and final amendments to
the NESHAP and are specified in § 63.741(f).
Comment: Commenter VI-B-63 noted that the formula in
§ 63.750(b) does not apply to emulsions, multi-phase products,
* and solutions having a large amount of nonvolatile surfactants,
* detergents, emulsifiers and/or wetting agents, or to nonideal
''• mixtures. We suggest that a scientifically valid test method be
JSf
I developed to clarify the rule.
Response: Based on the information collected from industry
sources and the related discussion at the roundtable meetings,
the Agency does not think this is a major technical issue, nor
does it think such issues will have a significant impact on the
facilities that will have to comply with the NESHAP or the
resulting emissions. The EPA believes that the standard, as
promulgated, provides affected sources and State and local
- agencies with enforceable requirements. Additionally, § 63.7(£}
'• provides the owner or operator of an affected source with the
"*- flexibility to use any alternative test method they want as long
"i as it is submitted and approved by the appropriate region or
- delegated State authority.
Comment; Commenter VI-B-63 suggested an allowable
equivalent test method to measure the vapor pressure of mixtures
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where the vapor pressure and molecular weight of one or more
components are unknown, or where the mixture is nonideal, or
where the manufacturer claims proprietary composition.
An appropriate test method may have to be developed, since
existing vapor pressure measurement methods are based on pure
liquids in which the vapor pressure does not change as a
proportion of the sample is vaporized. In the case of cleaning
solvent mixtures, the vapor pressure will decrease significantly
as a portion of the sample is vaporized. The effect is major for
the "contact cleaners" in aerosol cans. The liquid on the
surface, or on a wiping cloth, is significantly different in
composition from the "in-can" composition reported by the
manufacturer.
One feasible test concept would be to analyze the initial
vapor for composition. Based on the assumption of ideal behavior
of the vapor (as a gas at low pressure, which is a more valid
assumption than that of a liquid) and that current GC/MS
instruments can deal with and identify the components in very
small samples, partial pressures of the components could .be
calculated and the partial pressures of the VOC's in the vapor
summed up to obtain the initial total VOC partial pressure.
Response; Based on the information collected from industry
sources and the related discussion at the roundtable meetings,
the Agency does not think this is a major technical issue, nor
does it think such issues will have a significant impact on the
facilities that will have to comply with the NESHAP or the
resulting emissions. The EPA believes that the standard, as
promulgated, provides affected sources and State and local
agencies with enforceable requirements. Additionally, § 63.7(f)
provides the owner or operator of an affected source with the
flexibility to use any alternative test method they want as long
as it is submitted and approved by the appropriate region or
delegated State authority.
Comment: Commenter VI-B-63 mentioned that in § 63.742, the
semiaqueous cleaning solvent definition, there are industrial
cleaning materials and processes that do not fit the definition,
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but which do reduce emissions. This problem needs to be
acknowledged and addressed. The problem occurs when using an
AXAREL 52 a semiaqueous (as stated by DuPont, the manufacturer)
cleaning solvent. The cleaning tank contains 100 percent
AXAREL 52 and no water and is open. The rinse tank is all water,
in which the drag-out of the AXAREL 52 is removed from the part.
The AXAREL 52 floats to the surface in this tank and is skimmed
off. This process does not fit the NESHAP definition, but fits
the § 63.744(d) description as an exception.
.Response: Based on the information provided by the
commenter, it appears that even though AXAREL is defined by
DuPont as a semiaqueous, it does not meet the definition in the
NESHAP (i.e., a solution in which water is a primary ingredient--
at least 60 percent water) and therefore does not meet the
exclusion of semiaqueous cleaning solvents mentioned in
§ 63.744(d).
Comment: Commenter VI-B-48 asked what the visual continuity
check for waterwash system mean? Is there some guideline or is
it subjective to the-person responsible for monitoring the
system? Any small break in the water curtain would pass
overspray up the stack.
Response: The Agency does not have the necessary
information to provide guidelines on visual continuity checks.
Such criteria should be included as part of the source's
operating and maintenance (O/M) plan or operating permit
application and submitted to the proper authorities for
review/approval. Additionally, § 63.8(f) provides the owner or
operator of an affected source with the flexibility to use any
alternative monitoring method they want as long as it is
submitted and approved by the appropriate region or delegated
State authority.
Comment: Commenter VI-B-48 asked if maintenance procedures
for waterwash systems includes having to record and note (on a
daily basis) any chemical additives necessary for a waterwash
operation along with the required visual continuity/flow
characteristics check?
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Response: The Agency does not have the necessary
information to provide guidance on waterwash systems and the
necessary/required recordkeeping requirements. Such criteria
should be included as part of the source's operating and
maintenance (O/M) plan or operating permit application and
submitted to the proper authorities for review/approval.
2.7 SPECIALTY COATING DEFINITIONS
Comment: Two commenters (VI-B-52 and VI-B-63) questioned
the last sentence of the definition of "Electric or radiation-
effect coating" as being unclear. Did the EPA intend to exempt
"classified" coatings from the provisions of this subpart and not
from the definition itself? Suggested wording was provided by
the commenters.
Response: The Agency agrees that the word "as" needs to be
added to the definition. The revised definition in Appendix A of
the amended final rule is:
Electric or radiation-effect coating - A coating or coating
system engineered to interact, through absorption or
reflection, with specific regions of. the electromagnetic
energy spectrum, such as the ultraviolet, .visible,, infrared,
or microwave regions. Uses include, but are not limited to,
lightning strike protection, electromagnetic pulse (EMP)
protection, and radar avoidance. Coatings that have been
designated as "classified" by the Department of Defense are
exempt.
Comment: Commenter VI-B-63 requested that self-priming
topcoats be included in § 63.745(f)(2) of the final rule to be
consistent with the NESHAP rules.
Response: The Agency agrees with the commenter and has
added parenthetical text in the final amendments clarifying that
self-priming topcoats are included as topcoats.
Comment; Commenter VI-B-63 stated that pretreatment
coatings defined in appendix A to subpart GG includes coatings
used on composite radomes for adhesion and ease of stripping.
The epoxy primer is more difficult to remove, which results in
damage to the radome when removing the coating system. The
pretreatment coating definition needs to be modified to allow for
the use of this coating on composites. If the pretreatment
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coating definition is not changed, then a low VOC primer may be
required. This change to a low VOC epoxy primer could result in
excessive damage to the radomes as the coating system is removed.
Recommend that the definition be changed to: Pretreatment
coating means an organic coating that contains at least 0.5
percent acids by weight and is applied directly to metal or
composite surfaces to provide surface etching, corrosion
resistance, adhesion, and ease of stripping.
Response: The Agency agrees with the commenter in that
pretreatment coatings are used on composites and has modified the
definition as suggested.
2.8 CTG ISSUES
Comment; Commenter VI-B-56's Southern California operations
have identified a small number of extrudable/rollable/brushable
sealants currently in use that have VOC contents > 240 g/L. Of
most concern is Courtaulds Aerospace Products PR-1436-G E-2
corrosion inhibiting sealant which is used, in a brush on
application, on the commenter's 747 program. (The other
materials are low enough usage to qualify for low usage
exemptions.) The PR-1436 product has 268 g/L VOC and the
expected usage for 1996 at facilities in Southern California is
95 gallons. In order to continue using this material as the
commenter has for the past 10 years, the commenter requested that
the allowable VOC limit for extrudable/rollable/brushable
sealants be increased to 300 g/L.
Response: Since the specialty coating limits are meant to
reflect baseline levels and will have no significant impact on
emission reductions, the Agency raised the VOC limit to 280 g/L
(2.3 pounds/gallon) in the final CTG document. The 280 g/L limit
was selected (instead of the 300 g/L) based on the commenter's
data as to what is being used and is readily available.
Comment; Two commenters (VI-B-53 and VI-B-59) expressed
concern with the excessively broad definitions for certain
specialty coatings and their VOC limits in the CTG. Commenter
VI-B-53 requested that EPA clarify the specialty coatings
definitions to ensure consistent field implementation. In
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addition, commenter VI-B-59 stated several specialty coatings
used by the aerospace companies located in San Diego County are
not included in the proposed model rule (in the CTG).
Commenter VI-B-59 also raised several other concerns
involving: Clear Coating (VOC limit 720 g/L) - Considering that
there are clear coatings available for application to metals or
previously coated colored surfaces that comply with a general VOC
limit for topcoats of 420 g/L, the District recommends that this
definition be narrowed to allow only specific types of clear
coatings with some precisely defined, unique specified properties
to be qualified under this category. Otherwise, it should be
deleted from the proposal.
Lacquer (VOC limit 830 g/L) - The proposed definition is a
textbook definition of lacquers which simply states that these
coatings are polymer solutions rather than emulsions or
dispersions. There is no mention of any special requirements
which would justify the VOC limit being higher than the one used
in other industries. The District recommends that this
definition be revised by specifying what .special properties are
required for the aerospace industry or reduce the VOC limit to
680 g/L to be consistent with the current lacquer VOC standards
used for wood and architectural coatings.
Specialized Function Coating (VOC limit 890 g/L) - The
commenter acknowledged that it is difficult to provide
definitions for all specialized coatings used in the aerospace
industry. The definition does not specify what "limited
application" means and what amount of coatings represents "low
volume usage." It also does not identify what constitutes
"extremely specific engineering requirements." The suggested
language in this definition is too vague and creates a huge
loophole in the proposed model rule. The commenter recommended
deleting the proposed definition and including an additional
provision for small usage coatings. This provision would exempt
coatings used in volumes not exceeding the larger of the
following: 200 gallons per year for all such coatings, or a
specified percentage of volume, as applied, or all aerospace
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coatings used at a facility. This percentage should be
determined on a case-by-case basis and .should not represent more
than 5 percent of the total emissions from all aerospace coatings-
applied at the facility.
Commenter VI-B-59 also suggested that the following
specialty coatings categories and the corresponding definitions
and VOC limits be added to the proposed model rule:
- Bearing Coating (VOC limit 620 g/L),
- Dry Lubricative Materials for nonfastener lubrication (VOC
limit 880 g/L), and
- Caulking and Smoothing Compounds (VOC limit 850 g/L).
(Example definitions were also provided for these categories.)
Response; These issues involving various specialty coating
definitions and VOC content limits have been the cause of much
discussion and disagreement between industry representatives and
State and local enforcement agencies. Since the specialty
coating limits are meant to reflect baseline levels nationwide
and will have no significant impact on emission reductions, the
Agency has decided to add the three additional categories
suggested by commenter VI-B-59 with the suggested limits and
maintain the proposed definitions and VOC content limits that
were included in the draft CTG document. The Agency has not
collected sufficient data to determine a volume which represents
small usage coatings. Each State or local agency may determine
what levels are appropriate for small volume usage of specialty
coatings.
Comment: Commenter VI-B-61 suggested the following changes
to the CTG hand-wipe solvent cleaning requirements to bring the
CTG in conformity with the revised NESHAP: delete the words
"nonabsorbent, nonleaking" from the CTG and model rule (so that
state regulators are not encouraged to impose standards that are
impossible to achieve).
Response; The Agency agrees with the commenter and has made
the appropriate changes to the final CTG document to be
consistent with the NESHAP.
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Comment; Commenter VI-B-62 suggested modifying the
presumptive RACT requirements in Section 4.0 of the CTG. Many
"space program manufacturing and rework operations are located in
areas which are currently designated as nonattainment. Since
operations in these areas will be subject to both the CTG and the
NESHAP requirements, it is important to maintain consistency
between the two rules. The NESHAP includes, but exempts, space
operations from all restrictions except those for depainting
operations. Since the aerospace CTG does not address paint
removal, it seems to make sense to include, but exempt, space
operations in all CTG requirements in order to avoid confusion as
to the applicability of the CTG.
Response: The Agency agrees with the commenter and has
modified the appropriate section of the final CTG document.
2.9 METHOD 319
Comment; Three commenters (VI-B-51, VI-B-54, and VI-B-55)
raised several issues related to proposed Method 319. The
proposed Method 319 is very similar to another test method EPA
published as a proposed test method in 1993 and cited as a
reference in the proposed Method 319. Commenter VI-B-55
commented on that test method in a letter dated November 22, 1993
(a copy of that letter was attached) and stated those same
comments are equally applicable to the proposed Method 319.
Commenter VI-B-55 disagreed that Method 319 is a valid test to
evaluate the performance of paint overspray filters stating it is
technically flawed as was the 1993 proposed test method.
Response: The proposed test method is based on several
years of work performed for EPA and began with an exploratory
study, QA level IV, to determine the general magnitude at which
respirable-sized overspray particles may penetrate paint
arrestors. This study was performed under Cooperative Agreement
(No. CR 817083-01-0) with EPA and was completed in early 1994.
The test methodology -was based on that successfully used for
several years to quantify the aerosol penetration of ventilation
filters performed under a series of Cooperative Agreements with
EPA at QA level III and under a research contract with the
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American Society of Heating, Refrigerating, and Air-Conditioning
Engineers (ASHRAE). Building on the experience gained on the
exploratory program and the ventilation filter programs, a QA
level II program was undertaken in 1994-1995 to measure the
filtration efficiency of five types of paint arresters for a
liquid-phase challenge aerosol.
In 1995, the EPA defined the level of MACT for two- and
three-stage paint overspray arresters. In close cooperation and
coordination with EPA, tests of the MACT arresters were conducted
'.in late 1995 under contract with the Aerospace Industry
Association and-a commercial manufacturer to define the
filtration efficiency of the paint arresters determined by EPA to
represent MACT. These data were then used by EPA to set the
minimum filtration efficiency requirements for existing and new
facilities.
Comment: Three commenters (VI-B-51, VI-B-54, and VI-B-55)
took issue with the use of substitute materials for Method 319.
The commenters stated there is no correlation between physical
characteristics and paint particles are almost spherical in shape
despite the particle size, while KCl and oleic acid do not
produce round droplets.
Response: Method 319 will retain use of oleic acid and KCl
challenge aerosols. Over the 0.3 to 10 fj.m diameter size range,
collection of paint overspray in arresters arises primarily from
the filtration processes of inertial impaction and interception.
Impaction occurs when the inertia of the particle causes it to
impact the collection surface of the arrestor (e.g., a fiber of a
filter) as the airflow stream line it was following changes
course abruptly to flow around the collection surface.
Interception occurs when the airflow streamline the particle is
following comes within one particle radius of the collection
surface resulting in contact between the particle and arrestor.
Ideally, when a particle contacts the. collection surface, it will
?*
be captured. However, if the adhesion between the particle and
the collection surface is weak, the particle may be re-entrained
in the airflow and pass through the arrestor. This is often
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referred to descriptively as "particle bounce." Both impaction
and interception are dependent upon the adhesion between the
particle and collection surface. The combination of dry
collection surfaces and a dry particle will tend to have the
least adhesion while having the particle and/or collection
surface wet will tend to increase adhesion.
When overspray droplets reach the paint arrester in a
painting facility, they can be wet, tacky, or completely dry.
Also, the arrester itself may be wet from paint collection,
tacky, or dry. Thus, the actual condition for the particle-
collector interaction can range from dry-dry to wet-wet.
The reason for using oleic acid and potassium chloride (KCl)
is to span this range of particle-collector adhesion. The KCl
interacts with the arrestor as a dry overspray would, i.e., with
relatively low adhesion. The oleic acid interacts with the
arrestor as a wet overspray particle would, i.e., with relatively
high adhesion. While other liquid- and solid-phase material
could have been chosen, oleic acid and KCl were selected because
they are safe materials and have properties that are compatible
with accurate size measurement by the optical particle counter
(OPC) (i.e., they are nonlight-absorbing and have compact shapes
of spherical for oleic acid droplets and cubic or cubic clusters
for KCl). The use of KCl is consistent with ASHRAE's fractional
efficiency standard for ventilation filters (ASHRAE Standard
52.2P). Like Method 219, the ASHRAE method uses KCl to simulate
a dry challenge aerosol.
Actual paint was not selected because: (a) paint contains
volatile compounds which result in changes in particle size
between the upstream and downstream sample probe locations and
possibly between the probe location and the particle counter
measurement chamber; (b) the multi-component nature of paint -
droplets (containing suspended pigments and volatile carriers)
may lead to inaccurate size measurement by the optical particle
counter; (c) the volatile components of paint require greater
care by the test laboratory relative to room ventilation and
treatment of test duct exhaust; (d) as with oleic acid and KCl,
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even with actual paint at least two types would be required to
provide a liquid-phase and solid-phase challenge aerosol; and
(e) the collection efficiency for a given particle due to
itnpaction and interception is not related to the chemical content
of the particle but rather to its physical characteristics of
phase (liquid or solid) and aerodynamic diameter. Thus,
particles other than actual paint particles may be reliably used
so long as they are of equivalent phase and aerodynamic diameter.
By selecting oleic acid and KCl as simulants for wet and dry
overspray, the amount of testing needed is reduced because only
two challenge materials are used, particle sizing accuracy is
maintained, and safety and handling issues associated with
volatile paint components are avoided.
It is also important to note that because the efficiency is
-being determined by the ratio of downstream to upstream
concentration measurements made as a function of particle size,
the size distribution of the challenge aerosol is not of
importance (other than providing sufficient concentration of
particles over the measurement range 0.3 to 10 /im) . This differs
from gravimetric approaches where the size distribution has a
strong influence on the weight percent captured by the arrestor.
Comment: Two commenters (VI-B-54 and VI-B-55) stated the
NESHAP as proposed, will have a significant economic impact on
small businesses in that filter manufacturers will be required to
test all of the different filters that are sold to the aerospace
industry, particularly if they are required to certify complete
filtering systems which include products they do not manufacture
or market (i.e., combined multi-stage filtration systems). The
commenters went on to explain that they have been working since
1992 to develop a test method, using paint, that will give the
fractional efficiency of their filters. Earlier this year, the
commenters reached an agreement with an independent commercial
testing laboratory and the testing should be commercially
• available during the first quarter of 1997. The commenter asked
if a better method is available, should not the EPA take time and
effort to evaluate it?
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