&EPA
United States
Environmental Protection
Agency
Office of Air Quality
Planning and Standards
Research Triangle Park, NC 27711
EPA-453/R-94-082b
November 1994
Air
Chromium Emissions from Chromium
Electroplating and Chromic acid
Anodizing Operations -- Background
Information for Promulgated Standards
NESHAP
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November 1994
Chromium Emissions from Chromium
Electroplating and Chromic Acid
Anodizing Operations-Background
Information for Promulgated
Standards
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This report has been reviewed by the Emission Standards Division
of the Office of Air Quality Planning and Standards, EPA, and
approved for publication. Mention of trade names or commercial
products is not intended to constitute endorsement or
recommendation for use. Copies of this report are available
through the Library Services Office (MD-35), U. S. Environmental
Protection Agency, Research Triangle Park, North Carolina 27711;
from the Office of Air Quality Planning and Standards Technology
Transfer Network, U. S. Environmental Protection Agency, Research
Triangle Park, North Carolina 27711; or, for a fee, from the
National Technical Information Services, 5285 Port Royal Road,
Springfield, Virginia 22161.
Publication No. EPA-453/R-94-082b
ii
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ENVIRONMENTAL PROTECTION AGENCY
Chromium Emissions from Chromium Electroplating
and Chromic Acid Anodizing Operations--Background
Information for Promulgated Standards
Prepared by:
/"-^Bruce JordaKX
Director,^Mission Standards Division
U. S. Environmental Protection Agency
Research Triangle Park, North Carolina
(Date)
27711
1.- The subject national emission standards limit emissions of
chromium compounds from existing and new chromium
electroplating and chromium anodizing tanks. The standards
implement section 112 of the Clean Air Act as amended in
1990 and are based on the Administrator's determination of
July 16, 1992 (57 FR 31576) that chromium electroplating and
chromium anodizing tanks generate a large amount of chromium
compounds, a hazardous air pollutant listed in
section 112(b) of the Act.
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; 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; Office of Management and Budget; and other
interested parties.
3. For additional information contact:
Mr. Laiit Banker (MD-13)
Organic Chemicals Group
U. S. Environmental Protection Agency
Research Triangle Park, NC 27711
Telephone: (919) 541-5420
4. Copies of this document may be obtained from:
U. S. EPA Library (MD-35)
Research Triangle Park, NC
27711
National Technical Information Service
5285 Port Royal Road
Springfield, Virginia 22161
iii
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IV
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TABLE OF CONTENTS
1.0 SUMMARY . . .
1.1 SUMMARY OF CHANGES SINCE PROPOSAL . . .
1.2 SUMMARY OF IMPACTS OF PROMULGATED ACTIONS
2.0 SUMMARY OF PUBLIC COMMENTS
2.1 NESHAP DECISION PROCESS ......
2.2 PROCESS DESCRIPTION AND DESCRIPTION OF
CONTROL TECHNOLOGIES .....
2.3 SELECTION OF POLLUTANTS AND SOURCE CATEGORIES
TO BE REGULATED
2.3.1 Selection of Pollutants to be Regulated
2.3.2 Selection of Source Categories to be
Regulated . .
2 .4 SELECTION OF MACT/GACT APPROACH
2.5 SELECTION OF MACT FOR HARD CHROMIUM
ELECTROPLATING TANKS
2.5.1 Selection of the MACT Floor
2.5.2 Regulatory Alternatives Considered . .
2.5.3 Selection of MACT
2.6 SELECTION OF MACT FOR DECORATIVE CHROMIUM
ELECTROPLATING AND CHROMIUM ANODIZING TANKS
2.6.1 Decorative Chromium Electroplating--
Trivalent Chromium Electroplating
Process
2.6.2 Decorative Chromium Electroplaters--
Chromic Acid Electroplating Process . .
2.6.3 Chromium Anodizing Operations
2.7 SELECTION OF THE FORMAT OF THE STANDARD . . .
2.8 SELECTION OF THE EMISSION LIMITS
2.9 SELECTION OF DEFINITION OF SOURCE ......
2.10 SELECTION OF COMPLIANCE DATES .
2.11 SELECTION OF MONITORING REQUIREMENTS . . .
2.11.1 Enhanced Compliance Monitoring for
Packed-Bed Scrubber and Composite
Mesh-pad Systems
2.11.2 Selection of Proposed Operation and
Maintenance Requirements for
Packed-Bed Scrubber and Composite
Mesh-Pad Systems • •
2.11.3 Frequency of Monitoring ........
2.11.4 Alternate Compliance Monitoring for
Sources Using Fume Suppressants . . . .
2.11.5 Monitoring Requirements--General . . .
2.12 SELECTION OF TEST METHODS ....
2.12.1 Test Methods 306 and 306A
2.12.2 Demonstrating Compliance When Using
Fume Suppressants
2.12.3 Demonstrating Compliance When Using
Add-On Controls
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TABLE OF CONTENTS (continued)
REPORTING AND RECORDKEEPING
.13
13
2.13 SELECTION OF
REQUIREMENTS
2.13.1 Reporting/Recordkeeping Associated
With Fume Suppressants
Reporting Frequency . .
Reporting and Recordkeeping
Requirements--General
Requirements of the General
Provisions
14 OPERATING PERMIT PROGRAM
15 WORDING OF THE REGULATION
2.16 MISCELLANEOUS
2.13.4
2
2
Page
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2-138
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VI
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LIST OF TABLES
TABLE 2-1.
TABLE 2-2.
PUBLIC COMMENTS RECEIVED
SUMMARY OF COMPLIANCE MONITORING
REQUIREMENTS AND WORK PRACTICE STANDARDS
FOR THE FINAL RULE .....
Page
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VI1
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1.0 SUMMARY
On December 16, 1993, the Environmental Protection Agency
(EPA) proposed national emission standards for hazardous air
pollutants (NESHAP) for major and area sources performing hard
chromium electroplating, decorative chromium electroplating, and
chromium anodizing. A total of 62 comment letters were received
from industry, trade associations, regulatory agencies, and
environmental groups during the public comment period. As a
result of these comments, additional information was gathered,
evaluated, and incorporated into the EPA's responses to the
comments. The comments and responses are summarized in this
document. The comments and additional information gathered are
contained in the project docket and serve as the basis for the
revisions made to the standards between proposal and
promulgation.
1.1 SUMMARY OF CHANGES SINCE PROPOSAL
In response to public comments and as a result of the EPA
reevaluation, changes have been made to the proposed standards.
Significant changes are summarized below. All changes that have
been made to the regulation are explained fully in the responses
to the comments.
The following are expected to be the significant changes
discussed, listed in approximate order from most to least
significant:
1. Emission limits based on the control techniques that
form the basis for MACT have been revised. The emission limit
based on the use of a composite mesh-pad system is
0.015 milligrams of total chromium per dry standard cubic meter
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(mg/dscm) of exhaust air. The emission limit based on the use of
a fume suppressant is o.Ol mg/dscm.
2. Monitoring, reporting, and recordkeeping burden for
decorative chromium "electroplating tanks using a trivalent
chromium process that incorporates a wetting agent has been
substantially reduced.
3. The compliance date for all hard chromium
electroplaters and chromium anodizers is 2 years after
promulgation of the standards. The compliance date for
decorative chromium electroplaters is 1 year after promulgation
of the standards.
4. Monitoring requirements have been changed. Monitoring
provisions have been added for fiber-bed mist eliminators. Also',
the initial frequency of monitoring surface tension and foam
blanket thickness has not been reduced, but the final rule allows
a reduction in frequency if no exceedances occurred during a
given timeframe.
5. The operation and maintenance requirements in the
proposed rule have been revised, and are now work practice
standards.
6. Reporting and recordkeeping requirements have been
revised. The requirements of this rule and the interrelation of
these requirements with the General Provisions have been
clarified. The relationship between subpart N and subpart A is
presented in Table 1 of the rule.
7. Measurement of hexavalent chromium in lieu of total
chromium is allowed to demonstrate compliance with the emission
limits. A measurement method for hexavalent chromium is
specified (ion chromatography using a post column reactor
[ICPCR]).
8. Comments were solicited on regulating wastewater from
control devices used to comply with the standard. Based on
comments received, no regulation of wastewater is included in the
final rule.
9. The applicability of the standard has been clarified.
Hard chromium electroplating sources can use actual rectifier
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capacity to determine whether they are small or large if the
capacity is recorded by nonresettable ampere-hour (amp-hr) meters
or if their source has accepted a Federally-enforceable limit in
the title V permit. • Also, the final rule exempts tanks used and
qualified for research and development purposes.
10. Definitions have been revised where necessary to
clarify requirements of the rule.
1.2 SUMMARY OF IMPACTS OF PROMULGATED ACTIONS
The cost, economic, and environmental impacts to sources are
unchanged from proposal because the technologies that form the
basis of the MACT standards have not changed. The monitoring,
reporting, and recordkeeping costs associated with the final rule
have been reduced from proposal and are presented in
Section 2.13.3.
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2.0 SUMMARY OF PUBLIC COMMENTS
A total of 62 letters commenting on the proposed regulation
and the background information document for the proposed
standards were received during the public comment period. Three
late comments were also received and were considered in
finalizing this regulation. Comments from the public hearing on
the proposed standards were recorded, and a transcript of the
hearing was placed in the project docket. A list of commenters,
their affiliations, and the EPA document number of Docket A-88-02
assigned to their correspondence is given in Table 2-1.
For the purpose of orderly presentation, the comments have
been categorized under the following topics:
1. NESHAP Decision Process; . .
2. Process Description and Description of Control
Technologies;
3. Selection of Pollutants and Source Categories to be
Regulated;
4. Selection of MACT/GACT Approach;
5. Selection of MACT for Hard Chromium Electroplating
Tanks;
6. Selection of MACT for Decorative Chromium
Electroplating and Chromium Anodizing Tanks;
7. Selection of the Format of the Standard;
8. Selection of the Emission Limits;
9. Selection of Definition of Source;
10. Selection of Compliance Dates;
• 11. Selection of Monitoring Requirements;
12. Selection of Test Methods;
13. Selection of Reporting and Recordkeeping Requirements;
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TABLE 2-1. PUBLIC COMMENTS RECEIVED
Commenter
M. Corbin
D. Martin
C. O'Neill
W. Schott
W. Wenske
A. Maclnnes
D. Driesen
C. Garland
S. letter
B. Bateman
J. Tyler
K. Tyler
W. Schott
K. Kurucz
J. O'Brien
L. Hill
L. Liszewski
G. Hannabarger
J. Walton
E. Blankenship
D. Theiler
B. Harthoorn
D. Foster
R. Schenker
L. Strohm
J. Lamancusa
J. Cullen
E. Smith
G. Bender
K. Yiin
A. Turnbull
D. Preston
J. Keittdey
M. Tyler
J. Keithley
A. Roy
R. Curtis
Affiliation
Puget Sound Air Pollution Control Agency
Plumbing Manufacturers Institute
Washington State Department of Ecology
Kimre, Inc.
Kohler Company
United Airlines
Natural Resources Defense Council
Arkansas Department of Pollution Control and Ecology
Fort Recovery Industries, Inc.
Bay Area Air Quality Management District
Crown Plating, Inc.
Crown Plating, Inc.
Kimre, Inc.
Lockheed Missiles and Space Company
Lockheed Corporation
Hill Air Force Base
Kodak
Rohr, Inc.
Tennessee Department of Environment and Conservation
Wisconsin Department of Natural Resources
Deere and Company
Delta Faucet Company
General Electric Company
General Motors
Lacks Enterprises, Inc.
Masco Corporation
Reynolds Metals Company
RR Donnelley and Sons Company
Stanley Mechanics Tools
Tumbull and Associates, Inc.
Varnum, Riddering, Schmidt, and Hewlett
Crown Plating, Inc.
Hard Chrome Specialties, Inc.
Hard Chrome Specialties, Inc.
Allied Signal
American Airlines
Document No.a
IV-D-01
IV-D-02
IV-D-03
IV-D-04
IV-D-05
IV-D-06
IV-D-07
IV-D-08
IV-D-09
IV-D-10
IV-D-11
IV-D-12
IV-D-13
IV-D-14
IV-D-15
IV-D-16
IV-D-17
IV-D-18
IV-D-19
IV-D-20
IV-D-21
IV-D-22
IV-D-23
IV-D-24
IV-D-25
IV-D-26
IV-D-27
IV-D-28
IV-D-29
IV-D-30
IV-D-31
IV-D-32
IV-D-33
IV-D-34
IV-D-35
IV-D-36
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TABLE 2-1. (continued)
Commenter
E. Munsell
A.. Brooks
D. Drake
W. O'Sullivan
T. Allen
M. Bradley
D. Theiler
R. Colby
L. Carothers
L. Thorvig
C. Huston
G. Rountree
J. Graham
W. Ellsworth
H. Buffington
L. Zitko
H. Kimball
P. Leyden
B. Breisinger
G. Danielson
F. Chiappone
B. McGarvey
W. Sonntag
D. Martin
J. Keithley
R. Kennealy
R. Kennealy
R. Pelletier
D. Driesen
M. Lake
Affiliation
Department of the Navy
KCH Services, Inc.
Michigan Department of Natural Resources
Stew Jersey Department of Environmental Protection and
Energy
Hew York State Department of Environmental Conservation
Mortheast States for Coordinated Air Use Management
(NESCAUM)
State and Territorial Air Pollution Program Administrators,
and Association of Local Air Pollution Control Officials
(STAPPA/ALAPCO)
United Technologies
Minnesota Pollution Control Agency
Iowa Waste Reduction Center
Aerospace Industries Association
Atotech, Inc.
National Chromium
Snap-on Tools
ChromeTech, Inc.
Boeing
South Coast Air Quality Management District
Alcoa Company of America
Merlin Enterprises
Bausch and Lomb
National Aeronautics and Space Administration
National Association of Metal Finishers and The American
Electroplaters and Surface Finishers Society
Plumbing Manufacturers Institute
Crown Plating, Inc.
United Defense
United Defense
U. S. Department of Energy
Natural Resources Defense Council
San Diego County Air Pollution Control District
)ocument No.a
V-D-37
V-D-38
V-D-39
V-D-40
V-D-41
IV-D-42
IV-D-43
IV-D-44
IV-D-45
IV-D-46
IV-D-47
IV-D-48
IV-D-49
IV-D-50
IV-D-51
IV-D-52
IV-D-53
IV-D-54
IV-D-55
IV-D-56
IV-D-57
IV-D-58
IV-D-59
IV-D-60
IV-D-61
IV-D-62
W-G-01b
IV-G-02b
IV-G-03b
aDocket No. A-88-02.
bLate comment.
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14. Operating Permit Program;
15. Wording of the Regulation; and
16. Miscellaneous.
In some instances, several comments are presented
individually, but only one response has been written to reply to
all of the comments because the issues the comments raise are
interrelated.
2.1 NESHAP DECISION PROCESS
Comment: Four commenters (IV-D-07, IV-D-43,, IV-D-45,
IV-G-02) agreed with the EPA's interpretation of the statutory
language in section 112(d)(3) of the Clean Air Act (the Act)
concerning the MACT floor for existing sources. That is, they
agreed that the MACT floor for existing sources is properly
determined by first identifying the best performing 12 percent of
the existing sources, then determining the average emission
limitation achieved by these sources. One commeiiter (IV-G-02)
noted that had Congress intended for the floor to be set at the
88th percentile, they would have stated this. Five commenters
(IV-D-14, IV-D-15, IV-D-17, IV-D-28, IV-D-36) disagreed, stating
that the MACT floor should be set by looking at the average
emission limits achieved by each of the best performing
12 percent of existing sources, and be based on the lowest
(i.e., the 88th percentile). Three commenters (IV-D-14, IV-D-15,
IV-D-17) supported this interpretation by pointing out that the
EPA could always select a MACT standard that is more stringent
than the floor. Another commenter (IV-D-36) supported this
interpretation by pointing out that when such an approach is
taken, one always arrives at an emission limit that corresponds
to a technology (see discussion of next comment).
Comment: Three commenters (IV-D-07, IV-D-17, IV-D-28)
disagreed with the EPA's interpretation of "average." That is,
when determining the MACT floor, the average is calculated as the
arithmetic mean. When, however, an average calculated by this
method does not correspond to a technology, the median is
considered the average. Two of the commenters (IV-D-17, IV-D-28)
noted that this interpretation seems contrary to Congress'
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intent. Earlier versions of the Act identified the top 10 and
15 percent. In the latter case, it is unlikely that they would
:have meant the 93.5 percentile (IV-D-17). Likewise, this
', interpretation would infer that slight distributional variations
among data points should dramatically impact the MACT floor
(IV-D-28). Finally, one commenter (IV-D-07) argued that if an
arithmetic average does not correspond to a technology, the EPA
may select a MACT standard more stringent than the floor.
Response: On June 6, 1994 (57 FR 29196), the EPA
promulgated a final rule that presents the Agency's
interpretation of section 112(d)(A) of the Act regarding the
basis for the MACT floor. Under this interpretation, which is
referred to as the "Higher Floor Interpretation," the Agency
considers the emission limitations achieved by the best
performing 12 percent of existing sources and arrives at the MACT
floor by averaging those emission limitations. Furthermore, the
Agency interprets "average" to mean a measure of central tendency
such as the arithmetic mean or median. For example, if a source
category included fewer than 30 existing sources, the Agency
would consider the five best performing sources. If those
sources achieve emission reductions of 99, 98, 95, 94, and
93 percent, the arithmetic mean of the five values would be
95.8 percent. Because this value does not correspond to an
actual control efficiency being achieved, the Agency could set
the MACT floor at 95 percent, which is the median of the five
values.
The Agency has concluded that if Congress had intended the
EPA to set the MACT floor as the lowest reduction achieved by the
.best performing 12 percent of existing sources, section 112(d)(A)
would have been worded differently. For example, Congress could
have expressed such a meaning by requiring the floor to be set at
"the emission limitation achieved by all sources within the best
.performing 12 percent" or at "the emission limitation achieved by
....the least efficient member of the best performing 12 percent."
Therefore, the Agency believes that such an interpretation, which
is referred to as the "Lower Floor Interpretation," requires that
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words or concepts, which are not stated explicitly in the
statute, be added or inferred. Furthermore, the Higher Floor
Interpretation is supported by section 112(d)(3)(B), which
requires the MACT floor for existing sources in categories or
subcategories with fewer than 30 sources to be no less stringent
than the "average emission limitation achieved by the best
performing 5 sources." To infer a Lower Floor Interpretation
from this provision, Congress would have used language such as
"the emission limitation achieved by the 5th best performing
source."
Comment; One commenter (IV-D-02) asked for an explanation
of the EPA's authority for enforcing the final rule, and of the
civil and/or criminal penalties for any violations of the
standard.
Response: Section 113 of the Act allows the EPA to assess a
civil penalty of not more than $25,000 per day per violation of
the Act. Section 113 also allows the EPA to assess criminal
penalties for each day of a violation for knowing violations of
the Act.
2.2 PROCESS DESCRIPTION AND DESCRIPTION OF CONTROL TECHNOLOGIES
Comment: Eight commenters (IV-D-12, IV-D-22, IV-D-32,
IV-D-33, IV-D-34, IV-D-47, IV-D-52, IV-D-56) provided comments on
the process description. One commenter (IV-D-22) questioned the
statement that chromic acid is emitted in significant quantities
from all hard chromium electroplating and anodizing tanks, and
most decorative chromium electroplating tanks, given the fact
that the industry as a whole barely qualifies as a major source.
Two commenters (IV-D-47, IV-D-52) wished to clarify the
EPA's discussion of the boric-sulfuric acid anodizing process
that the EPA identified as a potential new process to replace
chromium anodizing. Both commenters stated that this process
cannot be assumed to have widespread applicability. Also, there
are other nonchromate processes besides boric-sulfuric acid
anodizing that are being evaluated. Based on this, the
commenters felt that the use of such processes should not be
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mandated; jbhat is, air pollution control device use should
continue to be allowed.
One commenter (IV-D-56) pointed out a distinction among
•decorative chromium electroplating processes: black chromium and
.white chromium. White chromium electroplating is the decorative
chromium electroplating process described in the proposed rule.
Black chromium electroplating is more like hard chromium
electroplating in terms of process parameters, and the commenter
recommended that black chromium electroplating be regulated with
hard chromium electroplating processes.
The other commenters (IV-D-12, IV-D-32, IV-D-33, IV-D-34)
pointed out that the proposed rule does not account for all hard
chromium electroplating processes. For example, one hard
chromium electroplating method uses low amperage and a longer
electroplating time (less amperage per square foot than
.decorative electroplating processes) such that emissions are
lower. These facilities suggested that the EPA has been led to
believe that this is not a viable process by larger facilities,
because mostly smaller facilities use such a process. This,group
of commenters also noted that the terminology used in the
proposed rule is incorrect. Proper terminology would
differentiate between industrial chromium electroplating and
decorative chromium electroplating.
Response: The process descriptions that were provided in
the preamble to the proposed rule were intended to provide an
overview. More detailed process descriptions are provided in
Chapter 3 of the proposal background information document (BID)
developed for this standard.
The EPA stated on page 65771 of the proposal preamble that
"... Chromic acid, a hexavalent chromium compound, is emitted in
significant quantities from all hard chromium electroplating and
anodizing tanks and from most decorative.chromium electroplating
....tanks." The EPA believes that this is a valid statement,
^especially when the toxicity of hexavalent chromium is
considered. Even though the total quantity of emissions may be
small compared to emissions of other pollutants, the cancer
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potency of hexavalent chromium warrants that the quantity of
emissions be considered significant.
In describing the chromium anodizing process, the EPA also
described some research that focuses on the use of a sulfuric-
boric acid anodizing process to replace chromium anodizing in
some instances. The EPA recognizes that research is being
conducted on replacement processes other than this one, and that
such processes are not sufficiently developed for use in
production. So, while the EPA encourages continued research in
this area, the final rule does not mandate this or any other
replacement process for chromium anodizing.
Comments were received regarding other processes (e.g., the
black decorative chromium electroplating process and the low-
amperage hard chromium electroplating process) conducted by this
source category that were not included in the process
description. In developing the standards, the EPA focused on the
operations that were widely regarded as being representative of
the source category. The final rule also discusses standards in
terms of hard chromium electroplating, decorative chromium
electroplating, and chromium anodizing. However, the definitions
of these processes have been expanded, and are now expressed in
terms of process parameters as well as by function. For example,
electroplating and anodizing operations are characterized in
terms of electroplating thickness achieved, current density, and
electroplating time, as appropriate. Therefore, regardless of
what name a facility has assigned to its process,, for the
purposes of the regulation the process will be regulated
according to its function, bath operating parameters, and desired
plating characteristics. For example, based on the description
provided by the commenter, black decorative chromium
electroplaters would be subject to the standards for hard
chromium electroplaters based on plating characteristics. The
expanded definitions for each subcategory will most likely
alleviate confusion concerning the applicability of the standard.
The EPA will provide States with additional guidaince on these
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types of applicability issues in the enabling document for this
rule.
'.:, The commenters that use a low-amperage electroplating
•_process were concerned that such a process would not be allowed
by the rule, even though emissions from this process are low.
The process does differ from other hard chromium electroplating
processes in that a lower amperage process is used. However, the
rule does not preclude the use of this process or any other
technique to meet the applicable emission limit. The rule does
require that the technique be demonstrated through performance
testing conducted in accordance with the test methods and
procedures identified in the final rule, and that compliance
monitoring be conducted to determine continuous compliance.
Comment: Seven commenters (IV-D-04, IV-D-06, IV-D-10,
IV-D-13, IV-D-43, IV-D-47, IV-D-55) provided comments on the
description of the add-on air pollution control devices such as
packed-bed scrubbers and composite mesh-pad systems. One company
(IV-D-13) noted that the proper terminology is one that refers to
a.composite mesh-pad system, not a composite mesh pad, because
high levels of control require a system of several composite mesh
.pads. The commenter goes on to provide a detailed description of
a multistage system and the function of each stage. This same
commenter also stated that their company should be named in the
rule because the system described uses the company's patented
design.
Another commenter (IV-D-06) noted an inaccuracy in the EPA's
control device description; the statement that a fiber-bed mist
eliminator is only installed at a government facility is
inaccurate. This commenter identified a commercial facility that
employs such a control device.
Several commenters (IV-D-10, IV-D-13, IV-D-43, and IV-D-47)
stated that the control efficiencies identified in the proposed
..";rule are overstated. According to the commenters, removal
^efficiencies for packed-bed scrubbers may be as low as 50 percent
-(IV-D-10, IV-D-43) and are only as high as 90 percent (IV-D-10,
IV-D-43), 95 percent (IV-D-47), or 97 percent (IV-D-13). Two
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commenters (IV-D-io, IV-D-43) also noted that the efficiency of
composite mesh-pad systems were overstated, and that they were
more likely in the range of 60 to 95 percent.
One commenter ('IV-D-55) stated that the proposed rule failed
to identify all of the possible control systems that could be
used to control chromium emissions from hard chromium
electroplating tanks. This commenter described the Merlin mist
control system and provided test reports to demonstrate that this
system can achieve the control levels required by the proposed
rule.
Response; In the final preamble and rule, the EPA has used
the terms composite mesh pad and composite mesh-pad system
consistently. Although the EPA gathered information based on
mesh pads developed by Kimre, Inc., it is not the EPA's policy to
endorse certain products or recommend them for use. In response
to comments received on the efficiency of composite mesh pad and
packed-bed scrubber systems, the EPA recognizes that efficiencies
will vary depending on the actual system. For exampl-e, a system
with a lower inlet loading will have a lower overall control
efficiency. Also, the manner in which a system is operated will
affect its efficiency. Given the potential problems in
identifying an overall control efficiency for these systems, the
final rule requires that an outlet concentration,, not an
efficiency, be achieved. The control efficiencies specified in
the proposed rule are typical for well-operated and well-
maintained systems operating at typical conditions. The EPA has
included some work practice standards in the fineil rule
[§ 63.342 (f)] to facilitate optimal control device operation to
meet the emission limits.
A benefit of expressing the standard in terms of a
concentration format is that it provides sources with flexibility
in terms of choosing the control device to meet the standard.
Therefore, if a system, such as the Merlin mist control system,
is tested using the specified method and procedures and meets the
applicable concentration limit, it can be used to comply with the
rule. The EPA does not have the resources to test every possible
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control system that could be used to achieve compliance with the
standard; testing focused on the major types of control equipment
:that were thought to achieve the best emission reduction.
Since the time of proposal, the EPA has confirmed that other
fiber-bed mist eliminators, in addition to the one that was
discussed at proposal, exist. The existence of multiple fiber-
bed mist eliminators is discussed in more detail in
Section 2.5.1, Selection of the MACT Floor for Hard Chromium
Electroplating Tanks.
Comment: Four commenters (IV-D-22, IV-D-32, IV-D-34,
IV-D-58) provided comments on chemical fume suppressants as a
control technology. One commenter (IV-D-22) noted that, contrary
to the EPA's description, his experience was that electroplating
baths that use fume suppressants do usually have ventilation
systems. The other three commenters disagreed with the EPA's
opinion on the potential negative aspects of foam blanket-type
fume suppressants. Two commenters (IV-D-32, IV-D-34) stated that
the explosion potential of certain fume suppressants could be
minimized by an effective safety training program. Another
commenter (IV-D-58) disagreed that fume suppressants cause
.process and product problems for hard chromium electroplaters and
pointed to data that show that inlet chromium emissions to a
scrubber were effectively reduced by using fume suppressants in a
hard chromium electroplating bath.
Response: In describing fume suppressants and tanks in
which fume suppressants are used in the preamble to the proposed
rule and the BID, the EPA described what was found to be true
based on their information gathering. Thus, it may be true that
it is one facility's experience that all sources that use fume
suppressants are ventilated. However, this facility may not be
familiar with sources located in other areas of the country, or
of smaller size, etc., that do not have ventilation. Likewise,
:when discussing the use of fume suppressants in hard chromium
.electroplating tanks, it has been the EPA's experience that they
•are not generally used because of performance problems. However,
this does not mean that fume suppressants are never used, or that
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fume suppressants that can be successfully used in hard chromium
electroplating tanks do not exist. In fact, on page 65781 of the
proposal preamble, the EPA describes the test results referred to
by commenter IV-D-58". Two systems are described---one in which
fume suppressants were used prior to a mist eliminator and one in
which a fume suppressant was used prior to a packed-bed scrubber.
When the fume suppressant was used in the tank controlled by an
older packed-bed scrubber, the use of the fume suppressant
enhanced the overall control of the system. In the case of the
fume suppressant being used prior to a new mist eliminator, only
a slight decrease in outlet emissions was observed. These data
suggest that fume suppressants can be used to enhance the control
level achieved by older control systems. Because the rule
requires sources to meet an emission standard rather than
specifying a particular type of control equipment, nothing
precludes the owner or operator from using any control scenarios,
such as those described in the proposal preamble, as long as the
standard is achieved.
In the preamble to the proposed rule, the EPA discusses the
potential safety hazards of foam blankets, a type of fume
suppressant. Foam blankets trap the hydrogen gas and chromic
acid mist in the foam layer. When heavy foam layers develop,
hydrogen gases can build up in the foam; if a spark is generated,
a hydrogen explosion can occur. The EPA agrees that foam
blankets can be used safely, but also believes that the potential
hazards of foam blankets should be known. The rule does not
preclude the use of foam blankets as long as the applicable
emission limit is met.
2.3 SELECTION OF POLLUTANTS AND SOURCE CATEGORIES TO BE
REGULATED
2.3.1 Selection of Pollutants to be Regulated
Comment: In presenting the health effects data that led to
the listing of the chromium electroplating and chromium anodizing
area source categories, the EPA requested comments on whether
there was a basis for removing any of the categories and
subcategories covered by the proposed regulation from the source
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category List. Comments were solicited primarily because the EPA
proposed regulation of decorative chromium electroplaters using
•the trivalent chromium electroplating process. The EPA was
-specifically interested in whether the delisting criteria of
section 112(c)(9) could be met, or alternatively, if it would be
appropriate to conduct a health assessment under
section 112(c)(3) prior to creating this subcategory and adding
it to the source category list. Two commenters (IV-D-26,
IV-D-59) responded specifically to this request for comment and
stated that the EPA should qonduct a health assessment under
section 112(c)(3) to determine the health effects of trivalent
chromium prior to creating a subcategory regulating this process.
•*
Both commenters argued that until such an assessment is made, the
trivalent chromium process should not be addressed in the rule.
Another commenter (IV-D-24) asserted that the rule must
acknowledge the fundamental toxicological differences between
trivalent and hexavalent chromium; the same commenter contends
that there are no data indicating that trivalent chromium is
carcinogenic. In addition to these three commenters, many other
commenters disagreed with the EPA's decision to regulate
decorative chromium electroplating sources that use the trivalent
chromium electroplating processes. Their comments did not
specifically respond to the request pertaining to information on
a section 112(c)(3) health assessment. These more general
comments are presented in Section 2.6.1 of this document, which
discusses selection of MACT for decorative chromium
electroplaters using a trivalent chromium electroplating process.
Response; The EPA has determined that the delisting
criteria of section 112(c)(9) cannot be met at this time for
trivalent chromium electroplating processes and that conducting a
health assessment under section 112(c)(3) cannot be justified in
light of the limited data available for trivalent chromium.
•Specifically, the EPA is aware of health concern issues
associated with trivalent chromium exposure that would not allow
the statutory criteria of section 112(c)(9) nor
section (112)(c)(3) to be met. The testing of trivalent chromium
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compounds is significantly more limited than that available for
hexavalent chromium and is considered inconclusive at this time.
The currently available trivalent chromium toxicological studies
have not shown dose-'related increases in carcinogenic response;
however, trivalent chromium compounds exhibit geriotoxic
potential. Of additional concern is the in vivo reduction of
hexavalent chromium to trivalent chromium which is believed to be
important in chromium's mechanism of carcinogenicity. There are
also reports that under certain environmental conditions,
trivalent chromium can oxidize to the hexavalent state.
2.3.2 Selection of Source Categories to be Regulated
Comment; The EPA separated the decorative chromium
electroplating source category into two subcategories:
electroplating baths using a chromic acid electroplating process
and electroplating baths using a trivalent chromium
electroplating process. The distinction between the
subcategories was based on process differences. One commenter
(IV-D-22) disagreed with one of the differences cited by the EPA;
i.e., that additional posttreatment and rinsing tanks may be
needed with trivalent chromium processes. The commenter pointed
out that trivalent chromium baths do not always have more rinse
tanks or have post dips. According to this commenter, trivalent
solutions rinse better than hexavalent solutions,,
Response; In creating a subcategory, the EPA discusses
characteristics that generally distinguish one subcategory from
another. It has been the EPA's experience that cidditional
posttreatment and rinsing tanks are required in some trivalent
chromium applications. In an industry as large eind diverse as
chromium electroplating, however, the EPA is aware of the fact
that some trivalent chromium applications may not; require
additional rinses. The description of the trivalent chromium
process in the proposed preamble was written generally so that
all known trivalent chromium processes would be covered by the
description. In addition, the regulatory definition for the
trivalent chromium process, not the process description, is the
determining factor in deciding the applicable requirements in the
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final rule. The definition used in the proposed rule defined the
trivalent chromium process as a process used for electro-
deposition of a thin layer of chromium onto a base material using
a trivalent chromium solution instead of a chromic acid solution.
In the definition, no mention is made of the other process tanks
used in the trivalent chromium electroplating line; therefore,
any process using a trivalent chromium solution to deposit
chromium onto a base metal would be subject to the requirements
in the final rule for the trivalent chromium process, regardless
of the existence of rinse or posttreatment tanks.
Comment: Six commenters (IV-F-01 [Altmayer, McRae,
Sonntag], IV-D-51, IV-D-58, IV-D-59) said that maximum cumulative
potential rectifier capacity was an inappropriate parameter for "
determining facility size. Commenters pointed out that sources
may have excess capacity for any of the following reasons:
1. Sources have purchased used equipment that is larger
than actually necessary;
2. The rectifier is sized to accommodate either .the largest
piece plated, striking that is performed at the beginning of the
process at high current densities, or some nonchromium
application that requires more capacity than chromium
electroplating;
3. The rectifier may be oversized to prevent chromium burn
or DC power supply failure or because actual capacity needs are
unknown; or
4. In full-scale production, more rectifier capacity may be
needed than in test or pilot operations.
One commenter (IV-D-58) indicated that using maximum
potential rectifier capacity would unfairly cause small
facilities with multiple tanks to be counted as large, even
though it is not customary to use all of the tanks at once. Two
other commenters (IV-D-17, IV-D-46) stated that if maximum
potential rectifier capacity was used as the size determinant,
,the rule would have to be more clear that it is only the
rectifiers associated with chromium electroplating that are of
concern. Finally, one commenter (IV-D-47) said that the
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distinction between small and large sources was not sufficient
because MACT was proposed for both categories, and the EPA has
made no determination as to what level of chromium emissions
constitutes an adverse effect on human health or the environment.
Ten commenters (IV-F-01 [Altmayer], IV-D-17, IV-D-21,
IV-D-28, IV-D-31, IV-D-36, IV-D-46, IV-D-51, IV-D-58, IV-D-59)
urged the EPA to explore alternatives to maximum potential
rectifier capacity for determining facility size. Commenters
suggested using actual annual ampere-hour usage, perhaps over the
most recent 12-month period, which could be demonstrated by using
nonresettable ampere-hour meters or through facility records.
Other commenters suggested raising the maximum potential ampere-
hour limit for small sources to 100 million amp-hr/yr (IV-D-46) ,"
or allowing sources to multiply the maximum potential rectifier
capacity by 0.75 to account for oversizing (IV-D-51). Two
commenters (IV-D-21, IV-D-28) suggested that, at a minimum, the
rule should clearly indicate how sources could accept
Federally-enforceable limits on their rectifier capacity that
would allow them to remain "small."
Response: The distinction between small and large hard
chromium electroplating facilities in the final rule has not been
changed from the proposed level of a maximum cumulative potential
rectifier capacity of 60 million amp-hr/yr. The EPA has,
however, included provisions in the final rule to allow sources
to use actual rectifier capacity or to limit their potential
rectifier capacity.
The final rule allows hard chromium electroplating
facilities to determine their size by using actual cumulative
rectifier capacity in lieu of the maximum potential capacity if
nonresettable ampere-hour meters are used on the chromium
electroplating tanks. The EPA believes that the use of such
meters will provide an accurate accounting of the rectifier
capacity consumed in a given year. Also, the final rule has been
clarified to state that only the rectifiers associated with hard
chromium electroplating should be used to determine maximum
cumulative potential rectifier capacity.
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The final rule also allows sources to establish
Federally-enforceable limits on their rectifier capacity through
the title V operating permit program. For example, a source may
exceed the 60 million amp-hr/yr cutoff based on maximum capacity,
and therefore be considered large. This source may, however,
have excess capacity onsite for any of the reasons provided by
the commenters. In such a case, the source may agree to a
Federally-enforceable limit that would restrict the actual
cumulative capacity used to less than 60 million amp-hr/yr. A
Federally-enforceable limit is obtained through the title V .
permit that is required by § 63.340(e) of the final rule.
To demonstrate compliance with an actual cumulative
rectifier capacity limit, sources are required to keep monthly
records of the actual cumulative rectifier capacity, and report
these records, in accordance with §§ 63.346(b) and 63.347(g) or,
(h). Once a source exceeds an actual cumulative rectifier
capacity of 60 million amp-hr/yr for any 12-month period or less,
the source is considered large and subject to the existing source
MACT standard for large sources. A subsequent reduction in
rectifier capacity would not result in less stringent
requirements; the standard for large sources would continue to
apply. Once a monthly record during the 12-month reporting
period indicates that a source has exceeded the rectifier
capacity of 60 million amp-hr/yr, the source has l year from that
month to come into compliance with the requirements for large
existing sources.
The EPA disagrees that the size distinction between small
and large hard chromium electroplating facilities "is not
sufficient." The size distinction was made to more effectively
evaluate the burden of the rule on small sources, given the large
number of small sources in this source category. The EPA
considers the issue of applying MACT to sources to be different
than the issue of size distinctions. The rationale for applying
-MACT to these sources is discussed in detail in Section 2.4.
Comment: Five commenters addressed the applicability of the
rule to the source category in general. One commenter (IV-D-60)
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indicated .that the EPA was incorrect to establish subcategories
based on type of deposit (hard chromium versus decorative
chromium electroplating). Instead, this commenter stated that
subcategories should be based on the amperage used in a process,
similar to the California regulations. Another commenter
(IV-D-18) indicated that coating (including chromium anodizing)
in the aerospace industry was to be covered under the control
techniques guideline (CTG) and NESHAP that were currently under
development for the industry and, therefore, should not also be
covered by this rule. One other commenter did not see his
process described in the proposed rule and was not sure how it
fit into the subcategories in the regulation. This commenter
(IV-D-35) described a process involving an alkaline solution used
to provide a chromate layer on copper foil. According to the
commenter, the alkaline solution is made up in part by using a
small amount of chromic acid that is subsequently neutralized.
The commenter stated that there are no emissions to the
atmosphere from this process, nor are air pollution control
devices or fume suppressants appropriate for it. As such it
should not be covered by the rule; this could be accomplished by
defining a chromic acid solution in terms of its pH. The
commenter also urged the EPA not to require any recordkeeping to
document that such a process is being used because the facility
would then be subject to the NESHAP and to title V permitting.
One commenter (IV-G-01) cites the notice of the initial list
of source categories (57 FR 31576), which states that only those
processes that use chromic acid in an electrolytic cell to
deposit chromium metal or to form an oxide film on a product are
covered. This commenter requested that the EPA clarify that
chromic acid and/or sodium dichromate used in conjunction with
sulfuric acid for parts cleaning is not classified as chromium
anodizing even though the surface of the base metal may be
oxidized.
Response: The EPA disagrees that the type of deposit
(i.e., hard chromium versus decorative chromium) is an
inappropriate basis for subcategories. The EPA believes that
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subcategories based on the amperage in a process would be
difficult to establish. In finalizing this MACT standard,
however, the EPA recognized that the definitions provided for
,hard chromium electroplating, decorative chromium electroplating,
and chromium anodizing may have been vague for some operations.
In the final rule, the EPA has revised these definitions to
express the various chromium electroplating and anodizing
operations in terms of process parameters such as plating
thickness achieved, current density, and plating or anodizing
time. The definitions are clear that electroplating and
anodizing operations are performed as part of a process; as such,
cleaning activities that involve chromic acid would not be
included. The EPA believes that the revised definitions will
assist affected sources and regulators in determining which
category is most appropriate for a given process, regardless of
the name assigned to that process. If the chromic acid
concentration and other process parameters associated with the
alkaline solution described by commenter IV-D-35 were
inconsistent with the description of the chromium electroplating
or anodizing tanks, the source is not subject to the regulation.
If a source is not subject to the regulation, no recordkeeping
burden is imposed by this rule. However, State or local
permitting agencies may need documentation to show that the rule
is not applicable.
There appears to be some confusion surrounding the
applicability of this rule to the aerospace industry. A GTG and
a NESHAP covering coating operations in the aerospace industry
are under development by the Agency; the aerospace NESHAP is
•expected to be promulgated by the summer of 1995. Neither the
aerospace NESHAP nor the CTG includes requirements for chromium
electroplating and anodizing operations. Those operations are
covered by this standard. It is not unusual for large
^facilities, such as aerospace facilities, to be covered by more
-than one MACT standard. Often, the EPA develops standards to
control operations that are conducted across many industries, and
are performed in a relatively uniform fashion. For example, the
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EPA has promulgated standards that apply to industrial process
cooling towers that could be located at many different types of
manufacturing facilities.
Comment; Pour -commenters (IV-D-24, IV-D-47, IV-D-52,
IV-D-58) recommended that research and nonproduction operations
be exempted from the rule as allowed by section 112(c)(7) of the
Act.
Response: The final rule exempts research or laboratory
operations as allowed by section 112(c)(7). For the purposes of
this rule, a research or laboratory source is defined as any
stationary source whose primary purpose is to conduct research
and development into new processes and products, where such
source is operated under the close supervision of technically
trained personnel and is not engaged in the manufacture of
products for commercial sale in commerce, except in a de minimis
manner.
Comment: Eleven commenters (IV-D-23, IV-D-24, IV-D-27,
IV-D-28, IV-D-32, IV-D-34, IV-D-42, IV-D-47, IV-D-52,- IV-D-58,
IV-G-01) suggested that the EPA should consider applying the rule
differently to area sources. One commenter (IV-D-42) suggested
that the EPA establish a lesser quantity emission rate to
distinguish area and major sources based on the potency of
hexavalent chromium.
On the other hand, other commenters stated that the EPA
should establish a de minimis emission level, below which sources
would not be subject to the rule. One commenter (IV-D-23)
pointed to a previous decision that demonstrates that the EPA has
the authority to establish, such cutoffs (e.g., Alabama Power Co.
v. Costle). Another (IV-D-47) stated that section 112(d)(l)
allows the EPA to establish such exemptions. Other commenters
proposed various cutoff levels: 5 to 10 pounds (IV-D-47),
1 million amp-hrs/yr (IV-D-47, IV-D-52), 0.013 tons of emissions
(IV-D-28), and less than 10 employees (IV-D-32, IV-D-34).
Another commenter (IV-D-27) proposed that sources in this
subcategory that fall below a de minimis level (e.g., 5 million
Amp-hr/yr) be exempt from the regulation. One commenter
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(IV-D-47) .suggested that the EPA perform a risk assessment to
determine the level below which the health risk is de minimis, or
•-..below which the cost of compliance exceeds the benefit of
-emission reduction. ' .
Response: Although this rule regulates both area and major
sources, the EPA has considered the potential burden on small
sources (most of which will also be area sources) by regulating
small, hard chromium electroplating facilities differently from
large, hard chromium electroplating facilities. Also, for all
source categories, the monitoring, reporting, and recordkeeping
requirements have been greatly reduced. The EPA does not support
a de minimis cutoff below which sources would not be subject to
«*
this rule because, for this source category, the EPA has
determined that emissions from area sources present, in the
aggregate, a threat of an adverse effect to human health or the
environment. For this reason, area sources performing chromium
electroplating and anodizing were placed on the list of area
sources to be regulated (57 FR 31588).
On the other hand, the establishment of a lesser quantity
emission rate for the source category would"only decrease the
population of area sources while increasing the population of
major sources. Further, because of the risk potential of
hexavalent chromium, the EPA has concluded that it is important
to regulate all sources with MACT. (See discussion in
Section 2.4.) The application of MACT to all sources results in
equivalent control levels being applied to all sources. At this
time, the EPA is not proposing to establish, for this rulemaking,
a lesser quantity emission rate for chromium emissions from this
•source category. The EPA is still evaluating a lesser quantity
.emission rate for other sources of chromium emissions, but no
decisions have been made to date. An Advance Notice of Proposed
Rulemaking will soon be issued on this topic.
Comment; One commenter (IV-D-18) states that the rule
should exempt facilities that,are complying with a similar State
or local rule that requires that chromium emissions be controlled
by 95 percent.
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Response: There are several State and local regulations
that require control of chromium emissions from chromium
electroplating and chromium anodizing tanks. Some of these
regulations are expressed in terms of a control efficiency or in
terms of mass emissions per amp-hr of operation (mg/amp-hr); as
such the requirements are not directly comparable to this rule.
If a source is subject to a State or local rule, it is also
subject to this NESHAP. However, States may revise their rules
to make them consistent with this rule. Alternatively, States
may choose to have their regulations determined equivalent by the
EPA. If a source is currently controlling emissions from
chromium electroplating and anodizing tanks to comply with a
State or local rule, they may have sufficient control in place to
meet this standard as well. Given the toxicity of chromium
compounds, the EPA does not support the exemption of any sources
within the regulated source categories. The toxicity of chromium
compounds is discussed in more detail in the following section.
2.4 SELECTION OF MACT/GACT APPROACH
Comment; Four commenters (IV-D-07, IV-D-40, IV-D-41,
IV-D-45) agreed with the EPA that it was appropriate to regulate
area sources with MACT standards. One of these commenters
(IV-D-07) noted that the EPA could not legally exempt sources
emitting 9 tons of chromium without examining the cumulative HAP
emissions of the entire facility, not just the chromium
electroplating processes. Ten commenters (IV-D-22, IV-D-24,
IV-D-28, IV-D-32, IV-D-34, IV-D-43, IV-D-47, IV-D-58, IV-D-59,
IV-D-69) questioned this approach, however, for various reasons.
One commenter (IV-D-22) did not see how the EPA could apply MACT
to area sources when the source category as a whole barely
qualifies as a major source. Five commenters questioned "... the
high toxicity of chromium compounds ..." as the basis for
applying MACT. Two of these commenters (IV-D-24, IV-D-58) noted
that different forms of chromium (hexavalent and trivalent) need
to be considered separately, especially when determining whether
to regulate all sources under MACT. A third commenter (IV-D-60)
provided information to support his claim that research to
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establish -the potential risk associated with chromium compounds
is flawed and is not intended to establish real risk. Two
..-commenters (IV-D-32, IV-D-34) stated that the risk of hexavalent
chromium to humans has never been accurately assessed.
Two commenters noted that the cost to area sources subject
to MACT is significant. One (IV-D-58) stated that the EPA failed
to consider the costs for area sources. The same commenter
compared this industry to the dry cleaning industry in which area
sources were regulated by GACT. Another commenter (IV-D-43)
noted that MACT could be an unnecessary burden on area sources
particularly if they are required to obtain title V operating
permits. (See related discussion in Section 2.14.) One
commenter (IV-D-24). questioned the EPA's decision to apply MACT
to area sources on the grounds that the Act does not intend a
residual risk analysis for area sources.
Three commenters (IV-D-24, IV-D-47, IV-D-58) suggested
specific changes in the way the EPA applies MACT. One commenter
(IV-D-58) suggested that the EPA apply GACT standards to small,
existing hard chromium electroplaters, decorative chromium
electroplaters, and chromium anodizers to allow the EPA to focus
its resources on facilities posing the greatest impact. Another
commenter (IV-D-47) suggested that the EPA establish a threshold
below which sources would be subject to GACT. Finally, one
commenter (IV-D-24) pointed out that it was important to have
separate standards for area sources even if GACT was as stringent
as MACT to preserve the intent of section 112(d).
Response: In determining whether to apply MACT or GACT to
the area sources performing hard chromium electroplating,
decorative chromium electroplating, and chromium anodizing, the
EPA considered the toxicity of chromium compounds emitted from
such sources and the availability of controls for sources in the
source categories.
In the final rule, all area sources continue to be regulated
by MACT standards. The basis for applying MACT to area sources
is that hexavalent chromium is emitted in significant quantities
from most source categories and is a known human carcinogen. In
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addition, .the EPA believes all chromium compound emissions should
be considered toxic because adequate data are not available to
determine otherwise. At least three epidemiological studies have
shown a strong association of lung cancer and occupational
exposures to mixtures of hexavalent and trivalent chromium. Even
though hexavalent chromium is a known human carcinogen, it
remains unclear whether any of the observed association is due to
trivalent chromium. Trivalent chromium is a necessary dietary
nutrient; however, there'is some evidence to indicate that
hexavalent chromium is reduced in part to trivalent chromium in
vivo. The link between hexavalent and trivalent chromium in vivo
is of concern. Very limited data suggest that trivalent chromium
may have respiratory effects on humans. No data on chronic or
subchronic effects of inhaled trivalent chromium in animals is
currently available. Due to the uncertainties associated with
the toxicity of trivalent chromium, the EPA has chosen to
regulate sources using a trivalent chromium process with MACT.
The toxicity of hexavalent chromium is well established;
hexavalent chromium is a highly potent, known human carcinogen.
Even though total emissions of hexavalent chromium from the
source categories are low relative to emissions of other
pollutants (such as solvents) from other source categories, the
EPA decided that MACT rather than GACT would be aipplied. The EPA
believes that this decision is justified because, given the
cancer potency, the residual risk analysis may still reveal a
risk greater than one in a million for facilities} using
hexavalent chromium. The EPA did not think it wets prudent to
establish a threshold based on risk below which sources were
subject to GACT given the potency of hexavalent chromium and
uncertainties in the toxicity data base discussed above. As one
commenter points out, the EPA has applied GACT in other
rulemakings, such as the dry cleaning NESHAP. However, the
pollutant of concern in that instance was perchloroethylene,
which is much less potent than hexavalent chromium.
In selecting MACT over GACT for area sources, the EPA also
evaluated the availability of control technologies and the cost
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of compliance for area sources. The control technologies that
form the basis for MACT are widely available and, as such, would
likely have been selected as GACT for most of the area source
categories. One exception is the large, hard chromium
electroplating source category, for which packed-bed scrubbers
may have been a possible alternative for GACT for existing
sources. In the EPA's analysis, however, a standard based on
composite mesh-pad technology was found to be reasonable for
large, hard chromium electroplaters. The final rule does,
however, allow existing small, hard chromium electroplaters to
meet an emission limit that is based on packed-bed scrubbers;
most of these small sources will also be area sources. The EPA
had determined that those existing area sources that fit the
"small" designation could experience economic hardship if forced
to meet a standard based on composite mesh-pad technology,
especially if a packed-bed scrubber system was already in place.
In light of comments received at proposal, the EPA has
reduced the monitoring, reporting, and recordkeeping requirements
for all sources (see discussion in sections 2.11 and 2.13,
respectively), which will further alleviate the burden on area
sources. Also, the compliance timeframe for decorative chromium
electroplaters has been increased to 1 year, and the compliance
timeframe for hard chromium electroplaters and chromium anodizers
has been increased to 2 years. These timeframes will allow
existing area sources more time to obtain the capital necessary
to purchase controls, train employees, and to implement
monitoring, reporting, and recordkeeping systems.
Many commenters point to section 112(d) of the Act to
support their reasoning that all area sources should be regulated
by GACT. Section 112(d)(5) does indeed allow an alternative
standard for area sources. The EPA, however, interprets this
•paragraph as authorizing the Administrator to establish GACT
""standards for area sources when the imposition of MACT is
determined to be unreasonable. -The Agency considers the
application of MACT to area sources in this source category to be
reasonable based on the risks of chromium compounds and the
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results of. the cost analysis, as discussed above. The EPA
believes that its interpretation is supported by section 112(f),
which discusses the need for the EPA to investigate and report to
Congress on residual" risk remaining from sources regulated under
section 112(d). Section 112 (f) (5) excludes area sources
regulated by GACT under section 112(d)(5) from this analysis. If
the intent of the Act was for all area sources to be regulated by
GACT and not subject to a residual risk analysis, it would not be
necessary for section 112(f)(5) to exclude only those area
sources regulated by GACT.
2.5 SELECTION OF MACT FOR HARD CHROMIUM ELECTROPLATING TANKS
2.5.1 Selection of the MACT Floor
Comment; Four commenters (IV-D-10, IV-D-41, IV-D-42,
IV-D-43) suggested that the MACT floor for new hard chromium
electroplating and chromium anodizing tanks should be based on
the use of a fiber-bed mist eliminator (FEME) because this is the
best technology in use. All of these commenters disagreed with
EPA's rationale for not requiring this technology as MACT for new
sources; they noted that the Act does not exclude government
installations, and in any event nongovernment installations
exist. One commenter (IV-D-41) knew of two such installations in
New York State, and was told by a vendor of FEME that 60 units
had been installed by them nationwide.
Response; The EPA has further investigated the prevalence
of FEME in response to comments received at proposal. As
discussed above, one commenter (IV-D-41) indicated that two FEME
had been installed in the State of New York and a total of
60 units had been installed nationwide. The two installations in
New York are described as "four-stage polypropylene pad
de-misters," indicating that there is some confusion in control
device terminology. The description given to the two
installations in New York is representative of a composite
mesh-pad system, not a FEME. As described in the preamble to the
proposed rule, FEME are typically installed downstream of an
existing control device and consist of hollow cylinders formed
from two concentric screens. The annular space between the
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cylinders -is filled with fibers, which are typically glass,
ceramic, plastic, or metallic materials. The EPA has also
contacted the vendor referenced by commenter IV-D-41 as having
60 fiber-bed units installed nationwide. Again, it appears as if
the term fiber bed is being used to describe what is actually a
composite mesh-pad system. The vendor confirmed with EPA that
they were discussing the installation of composite mesh-pad
systems with commenter IV-D-41, not fiber-bed systems.
One other commenter also indicated that additional
facilities were using FEME to control chromium emissions from
hard chromium electroplating and chromium anodizing tanks
(IV-D-10). In addition, all four commenters stated that FEME
should be considered as the basis for MACT for new sources.
Based on information gathered by EPA since proposal, a total of
five facilities are known to be using FEME to control chromium
emissions from affected hard chromium electroplating and chromium
anodizing tanks. These five facilities represent different sizes
of hard chromium electroplating and chromium anodizing
operations.
Emission test data were obtained from four of the five
facilities using FEME (see Item No. IV-B-01 of Docket A-88-02).
However, after a thorough evaluation, it was determined that none
of the emission test data available were adequate to establish an
emission limit based on the use of fiber-bed units.
The test results from one facility were incomplete to assess
the performance of fiber-bed units. The test results from the
other facilities were adequate to evaluate the performance of
FEME; however, the limited data are not sufficient to establish
an emission limit which must be met on a continuous long-term
basis based on the use of FEME. In one case, at both the inlet
and outlet, only one sample port was installed. At the inlet,
only a single point was sampled. At the outlet, only one
'traverse was made, when two traverses should have been performed.
..'Based on EPA's previous experience in sampling at electroplating
facilities, sampling a single point or a single traverse is not
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acceptable for providing accurate and representative emissions
data.
In order to use emissions test results for the purposes of
establishing emission limits, the Agency also requires that the
quantity of emissions captured by the sample catch exceed the
detection limit of the analytical method by a factor of five.
This requirements ensures that the measured data are accurate to
within 10 percent. Data from the remaining two facilities fall
below this guideline. Therefore, the data must be treated as
qualitative rather than quantitative results; they may not be
used to establish achievable emission limits. Based on this
qualitative assessment, it appears that FEME offer excellent
control potential.
In evaluating control technologies, the Agency also must
consider the sustainability of any performance level. As
discussed above, the Agency does not have data to establish
emission limits associated with the FEME technology. In
addition, EPA is concerned with the long-term performance of
these systems because of the tendency of the fiber beds to plug.
In other contexts, most vendors of FEME systems do not recommend
their use as primary pollution control systems. Rather, they
recommend that coarse prefiltering be provided upstream of the
fiber beds to prevent plugging. The prefiltering devices range
from a series of mesh pads to a complete packed-bed scrubber
unit. At present, there are no long-term data available to
assess any actual deterioration or operational problems
associated with FEME. Fiber-bed mist eliminators to control
chromium electroplating and anodizing tanks have only recently
been installed as a result of local air district requirements;
therefore, it is unlikely that any long-term data are available.
Because of the uncertainties in both the measured FEME
performance data and the potential long-term variability of the
system performance, the Administrator cannot at this time
determine a more stringent emission limit could be achieved based
on the application of FEME technology for new hard chromium
plating or chromium anodizing operations. Therefore, the MACT
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standard is 0.015 mg/dscm for new hard chromium electroplating
operations and is 0.01 mg/dscm for new chromium anodizing
operations. [See discussion of emission limits in Section 2.8.]
As set forth in the proposal, these emission limits were based on
the performance level which could be achieved by composite
mesh-pad systems and fume suppressants, respectively. These
emission limits correspond to an overall emission reduction of
99.8 percent for composite mesh-pad systems and 99.5 percent for
fume suppressants. Based on available data, the Administrator
has been unable to conclusively determine that the performance
achieved in practice by the FEME is superior, considering
long-term performance, to that of either the composite mesh-pad
system or fume suppressants. Therefore, the final MACT
performance level of new hard chromium electroplating and
chromium anodizing operations is -unchanged from the proposal.
However, the limited data do suggest that FEME systems can
achieve the emission limits established for composite mesh-pad
systems and fume suppressants. Because this standard is a
performance standard, the use of a specific technology is not
mandatory; therefore, either system (or any which meets or
exceeds this performance level) may be used for control of
emissions from new hard chromium electroplating and chromium
anodizing operations.
In order to facilitate the use of FEME to achieve compliance
with the standard, monitoring provisions have been included in
the final rule for use with FEME. The pressure drop across the
fiber-bed unit is identified as the compliance monitoring
parameter because of the relationship between pressure drop and
the performance of the unit. Performance of the fiber-bed unit
will decrease as a result of plugging of the bed if the water
spray system is not activated in response to an increase in the
pressure drop. Therefore, it is required that the pressure drop
be monitored and recorded once per day in the final rule. Any
.deviation outside the established parameter range would
constitute a violation of the standard. The test methods in the
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proposed rule are suitable for demonstrating compliance with the
standard, regardless of the control technology employed.
Comment; Two commenters (IV-D-07, IV-D-43) disagreed with
the methodology used by the EPA in calculating the floor. One
commenter (IV-D-43) pointed out that the calculation should be a
straight arithmetic average, not a median, and account for the
five percent of the facilities using the composite mesh-pad
system. As such, the MACT floor would be 0.023 mg/dscm as
presented in the preamble to the proposed rule. The other
commenter (IV-D-07) also noted that in determining the floor, the
EPA can only exclude sources achieving low emission levels due to
very recent BACT and LAER determinations. The EPA, according to
this commenter, may not exclude other sources achieving these
emission levels from the floor determination without positive
information that these levels came about because of BACT or LAER
determinations. The commenter points to section 112(d) as the
source of this information.
Response; The EPA believes that the use of a median for
determining the average emission limitation is warranted, as
discussed in Section 2.1.
2.5.2 Regulatory Alternatives Considered
Comment; Eight commenters (IV-F-01 [Altmayer], IV-D-12,
IV-D-17, IV-D-21, IV-D-48, IV-D-49, IV-D-53, IV-D-58) suggested
that the EPA was too limiting in the regulatory alternatives for
hard chromium electroplating operations. These commenters said
that the EPA should have accounted for sources (especially small
sources) in this subcategory that could use fume suppressants to
comply with the standard, instead of locking sources into a
control technology such as a packed-bed scrubber. Four
commenters (IV-D-17, IV-D-48, IV-D-49, IV-D-58) proposed that the
EPA allow new and existing hard chromium electroplating
operations the option of meeting the same surface tension limit
allowed for decorative chromium electroplating operations using a
wetting agent-type fume suppressant. One of these commenters
(IV-D-17) contended that the EPA did not present sufficient
evidence to support that fume suppressants in hard chromium tanks
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are less e_ffactive than those in decorative chromium tanks. Two
commenters (IV-D-48, IV-D-58) further argued that there are fume
suppressants available that do not cause pitting in hard chromium
electroplating tanks (brochure provided); one of these fume
suppressants works by forming a foam blanket only near the anode
and cathode. According to one commenter (IV-D-48), the South
Coast Air Quality Management District (SCAQMD) has approved the
use of such a fume suppressant in conjunction with poly balls for
controlling chromium emissions from hard chromium electroplating
tanks.
Response: The EPA has selected an emission limit format in
order to provide sources with the flexibility to choose the
emission control strategy best suited to their facility. The
regulation only requires that any strategy selected meet the
emission limits set out in the rule. As such, hard chromium
electroplating sources can use fume suppressants to achieve
compliance with the standard, as long as compliance testing and
ongoing compliance monitoring demonstrates that the emission
limit required by the standard is being achieved.
The Agency allows decorative chromium electroplating and
chromium anodizing sources to achieve a surface tension limit in
lieu of conducting a performance test if the criteria of
§ 63.343(b)(2) or (3) are met. This provision was included in
the standard because the EPA recognized that some decorative
chromium electroplating and chromium anodizing tanks do not have
ventilation stacks such that a source test could be performed.
This is not the case with hard chromium electroplating tanks.
Given the quantity of chromium emitted from a hard chromium
electroplating tank, it is the Agency's experience that all such
tanks have ventilation systems to meet Occupational Safety and
Health Administration (OSHA) requirements. Thus, testing to
demonstrate initial compliance with the standard should not be an
implementation problem for facilities with hard chromium
•electroplating tanks that wish to use fume suppressants.
The EPA has revised the rule to clarify that monitoring
requirements are a function of the control technique used, and
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are not source category-specific. Thus, the rule requires all
sources using fume suppressants with wetting agents, or foam
blankets to monitor the surface tension or foam thickness,
respectively, to demonstrate continuous compliance with the
standards regardless of the source category. The value of the
monitoring parameter used for ongoing compliance determinations
is either (1) specified in the final rule; e.g., a source may
accept a minimum foam blanket thickness of 1 inch as compliant;
or (2) set during the initial compliance test; e.g., if a source
using a foam blanket chooses to set the compliant foam thickness
value. The monitoring frequency, and recordkeeping and reporting
associated with monitoring, that is identified in the proposed
rule is also control technique-specific.
Comment: One commenter (IV-D-24) suggested that the section
of the proposed rule that allows alternate control technologies
(§ 63.343(d)) also specify the timeframe within which the EPA
would approve the alternate technology.
Response; The installation of alternative control
technologies do not have to be approved under the final rule. It
is only necessary for the monitoring parameter that will be used
to ensure continual compliance with the standard be approved, or
if an alternative test method is used to demonstrate initial
compliance, the alternative test method must first be approved by
the governing agency. As stated in section 63.343(d) of the
proposed (and final) rule, sources using air pollution control
devices not listed in the section are required to submit, among
other things, verification of performance and appropriate
operating parameters to be monitored to establish compliance with
the standards. The testing procedures used for verification
would likely be consistent with those laid out in § 63.344(c) of
the final rule. If not, the alternate test procedures must be
submitted for approval in accordance with § 63.7 (f) of the
General Provisions. Section 63.7(c)(3) specifies that the
Administrator will approve or deny the alternate test procedures
within 30 days of receipt of the test plan and any supplementary
information requested by the Administrator. If silternate
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monitoring requirements are requested, these alternate
requirements should be requested in accordance with
.§ 63.343(c)(8) of this rule and § 63 . 8 (f) (4) (i) of subpart A.
;-The Administrator, as stated in § 63.8 (f) (5) (i) , will approve or
deny the alternate monitoring methods within 30 days of receipt
of the alternate plan and any supplementary information
requested.
Comment; Several commenters responded to the EPA's
solicitation for comment on the feasibility of limiting or
prohibiting wastewater discharges from sources covered by the
proposed rule. Two commenters (IV-D-40, IV-D-43) stated that
wastewater recycling should be incorporated into the rule.
However, 21 commenters did not think that wastewater should be
regulated. Thirteen commenters (IV-D-06, IV-D-14, IV-D-15,
IV-D-17, IV-D-22, IV-D-26, IV-D-31, IV-D-37, IV-D-47, IV-D-52,
IV-D-58, IV-D-59, IV-D-61) noted that recirculated scrubber water
and washdown water cannot always be returned to the
electroplating bath because of the potential for contamination.
This is especially a concern when multiple process tanks
performing different operations (decorative chromium
electroplating, chromium anodizing, nonchromium operations, etc.)
are vented to the same control system. In lieu of recirculation,
scrubber water is routed to an on site wastewater treatment plant
prior to being discharged to the POTW. One commenter (IV-D-29)
pointed out that to alleviate contamination concerns,
recirculated water would have to be treated prior to reuse, but
that such a practice would itself generate a significant quantity
of waste. Two commenters (IV-D-14, IV-D-37) noted that the mass
.loading of chromium in the scrubber water is typically low and
can be sent to directly to a POTW. Other comments questioning
the EPA's rationale for regulating wastewater pointed out that:
1. The economic incentive to recycle already exists
r'(IV-F-01 [Altmayer] , IV-D-09, IV-D-23, IV-D-61);
2. There may not be capacity in the process to accept
additional water volume (IV-D-58);
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3. The use of a scrubber for its secondary evaporative
benefits is questionable because any benefit would likely be
offset by increased energy consumption (IV-D-26, IV-D-59);
4. The EPA may not have statutory authority to regulate
wastewater or any source that does not cause air emissions
(IV-D-17, IV-D-18, IV-D-23); and
5. There is limited benefit to regulating a source that is
already regulated by an effluent standard (IV-D-17).
Finally, three commenters were concerned that a rule limiting or
prohibiting wastewater discharge may be too narrowly defined.
For example, one commenter (IV-D-36) pointed out that a rule
covering wastewater discharge would have to include more options
than the two proposed by the Agency because there are other
potential uses for recycled water. Another commenter (IV-D-51)
noted that it was not prudent to regulate wastewater because the
EPA is not familiar with all existing or future technologies, or
the larger matter of total waste minimization for an entire
industry. The third commenter (IV-D-61) suggested that the EPA
should wait until technology that eliminates the discharge of
wastewater becomes available and affordable to industry before
requiring industry to comply with wastewater standards that may
lead to lower-quality products or price increases.
Response: In the preamble to the proposed rule, the EPA
solicited comments on a possible standard in which sources would
be required to recirculate scrubber water until it reaches a
certain chromium concentration; then, the water could be
discharged. An even more stringent requirement presented by the
EPA for comment was one in which sources would not be allowed to
discharge any wastewater resulting from the use of composite
mesh-pad and packed-bed scrubber systems. The benefit of such
requirements is that the quantity of chromium-containing
wastewater would be reduced.
The comments received at proposal offered many technical
reasons for why neither of these requirements would be feasible
for many sources. In light of these comments, the EPA has
reevaluated the alternatives associated with wastewater. There
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appear to _be many instances in which recirculation of wastewater
is not technically feasible because it could introduce
contamination into the plating baths. Also, there are some
facilities that have' indicated that they do not have capacity to
accommodate all recycled water. In soliciting comments on the
wastewater requirement, the EPA assumed that the requirement
would be technically feasible for sources and therefore performed
at minimal or no costs. In light of comments received, the
technical feasibility of the wastewater requirements is
uncertain, and the EPA has therefore chosen not to include such a
requirement in the final rule.
Even though not regulated by this NESHAP, wastewater sources
from chromium electroplating and chromium anodizing tanks are not
unregulated. The Agency recognizes the environmental benefits of
reducing wastewater containing chromium. The Office of Water is
currently revising effluent guidelines that apply to the chromium
electroplating and chromium anodizing sources. The Office of
Water is currently investigating "end of pipe" limits -that apply
to chromium emission sources, as well as in-plant methods to
limit the quantity of wastewater that can be discharged. These
guidelines are scheduled to be proposed in two separate phases,
with Phase I to be proposed in the Fall of 1994, and promulgated
by May 1996. Phase I will cover facilities that sell products in
the following market sectors: aerospace, aircraft, electronic
equipment, hardware, mobile industrial equipment, ordnance, and
stationary industrial equipment. Phase II is scheduled to be
proposed by December 1997 and promulgated by December 1999 and
will cover sources that sell products in the following markets:
bus and truck, household equipment, instruments, motor vehicles,
office machines, precious and nonprecious metals and instruments,
railroad, and shipbuilding. After completion of these two
phases, all sources in the source categories subject to this
NESHAP will be covered by a revised wastewater effluent
..guideline.
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2.5.3 Selection of
Comment ; Four commenters (IV-D-13, IV-D-24, IV-D-31,
IV-D-58) had questions on the EPA' s cost and economic impact
analysis that was considered in selecting MACT for hard chromium
electroplating operations. One commenter (IV-D-13) stated that
the cost to retrofit existing control equipment was overstated.
Two commenters (IV-D-24, IV-D-58) thought that the EPA's analysis
was flawed for several reasons. First, these commenters thought
that costs were understated because the EPA did not consider the
cost of shutdown for a facility to permit, install, and test an
air pollution control device. One of these commenters (IV-D-24)
estimated that their cost would be greater than $100,000/lb of
chromium reduction, much greater than the $l,850/lb estimated by
the EPA. The other (IV-D-58) noted that the costs did not
account for the fact that multiple control devices would be
necessary to meet the standards. These commenters also felt that
the cost analysis was flawed because it assumed that all forms of
chromium have the same toxicity. Thus, the EPA has overestimated
health benefits and underestimated the cost per pound of
pollutant reduced. Finally, one commenter (IV-D-31) questioned
the EPA's statement that the majority of cost increases resulting
from additional emission controls can be passed on to customers .
The commenter wanted to know the basis of this statement, and the
framework for the conclusion that product prices will increase by
less than 1 percent.
Response : The EPA considers the cost estimates presented in
the preamble to the proposed rule to be generally representative
of industry costs to achieve compliance with the rule. The EPA
recognizes that in an industry of over 5,000 sources, there is
going to be variation in the cost to achieve compliance with the
standard. The costs developed by the EPA are not intended to
represent every facility within the source category, but are
intended to represent the source category in general. Whereas
commenter IV-D-24 feels that costs will be much higher than those
estimated by the EPA, there are likely other sources whose costs
will be lower.
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Regarding the comment that the EPA underestimated costs
because it did not account for the need for multiple control
..devices, the Agency did account for the fact that medium and
large-sized facilities have more than one tank and would
therefore require more than one control device per facility. The
EPA assumed that at such facilities, multiple tanks could be
manifolded to one control device, thus saving on capital costs,
but did not assume only one control device would be needed when
large numbers of tanks are present. (For more details on costing
methodology, refer to Chapter 5 of the proposal BID and to the
New Technology Document.) Regarding the comment that the EPA
overestimated retrofit costs, these costs were supplied by
vendors to the industry. The commenter is a supplier of
composite mesh pads who sells the pads to vendors that actually
install control systems. Although his costs to vendors may be
less than those presented in the proposal preamble, end users
purchase equipment from vendors, not the original equipment
component supplier, and will therefore incur those costs charged
by the vendors.
To clarify the cost estimates presented, these costs are
installed costs and thus do account for the cost of installation.
Shutdown costs (i.e., downtime) were not included because, based
on information received by the EPA, the majority of shops with
multiple tanks have several control system configurations for
controlling the tanks, and one system can be operated while the
other system is being upgraded or replaced. In addition,
facilities have the option of installing the equipment during a
normal shutdown of the plant. Data gathered on the industry
indicate that facilities typically shutdown twice a year for a
one week period. A problem with shutdown may exist for small
shops or shops that operate 365 days per year and have only one
control system. However, measures such as increased production
prior to shutdown could be used to minimize production losses.
..Although the costs of performance testing are not included as
part of equipment expenditures, the effect of these costs was
considered by the EPA in selecting the level of the standards.
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Also, in response to commenters that stated that the EPA
overestimated environmental benefits, the EPA estimated the costs
per quantity of hexavalent chromium removed in developing impacts
for the standard. This was done because all chromium emitted
from chromic acid electroplating and anodizing tanks was assumed
to be hexavalent chromium.
The EPA's analysis of the economic impacts of the standard
indicated that final product prices will increase by less than
1 percent. Because it would not be feasible to analyze the
impact of the regulation on all products that are chrome plated,
the EPA's Economic Impact Analysis (EIA) examined the impacts on
five different products. Of these five, three of the products
are hard chromium electroplated: automobile parts, industrial
rolls, and hydraulic cylinders. For each product analyzed, the
EIA provided estimates of the original plating cost and both
the percentage increase and the actual dollar increase in
electroplating cost. Then, if possible, the EIA used the
increased cost of electroplating, along with an estimated price
of the final product, to estimate a price increase for the final
product. Using this methodology, the EIA arrived at the
conclusion that the final product price would not exceed
1 percent for any of the products analyzed.
The percentage increase in electroplating costs estimated in
the EIA did exceed one percent in some instances,, However, the
EIA indicated that these cost increases could be passed on to the
consumer for the following reasons. The primary reason is
because the demand for most electroplated products is a derived
demand. In other words, the parts that are electroplated are
intermediate goods in the production of the final product. As a.
result, the estimated increase in electroplating cost is such a
small percentage of the total cost of producing the final product
that the producer of the final product could raise the final
product price minimally (less than one percent) to recover the
cost increase associated with purchasing the electroplated parts.
Another factor that should make it easier for hard chromium
electroplaters to pass cost increases is that there are limited
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substitutes available for hard chromium electroplated parts.
Thus, customers are less able to switch to a different product
:when faced with higher prices for hard chromium electroplating.
(For more details on the EIA, refer to Chapter 8 of the proposal
BID and to the New Technology Document.)
Comment: Six commenters (IV-D-17, IV-D-24, IV-D-28,
IV-D-31, IV-D-36, IV-D-58) stated that the proposed standard for
large, existing hard chromium electroplaters is inappropriate.
Four commenters (IV-D-17, IV-D-24, IV-D-28, IV-D-58) did not
think that sources that had installed packed-bed scrubbers prior
to proposal of the rule should have to upgrade to composite mesh-
pad systems. The commenters did not believe that such an upgrade
was cost justified; one (IV-D-17) stated that large facilities
would have at least as much difficulty in obtaining capital as
small facilities. One of these commenters (IV-D-28) also pointed
to the language of section 112(d)(3) to justify that requiring
this upgrade is inconsistent with the Act; sources with packed-
bed scrubbers meet the requirement that existing sources be
subject to a control requirement no less stringent than the MACT
floor.
Other commenters (IV-D-31, IV-D-36) also agreed that the
standard should be set at the MACT floor because: (1) the
improvement in air emissions over the MACT floor is minimal but
cost and energy impacts are not; (2) the data on the number of
control systems and their effectiveness is from vendors hoping to
mandate their systems; and (3) a level of 0.013 mg/dscm is not
consistently achievable with composite mesh-pad systems under the
normal range of operating conditions. Another commenter
(IV-D-58) agreed with this last point and cited test data to show
that a level of 0.013 mg/dscm could only be met if composite mesh
pads are preceded by process controls such as fume suppressants
or another air pollution control device. This same commenter did
not believe that the data provided by the EPA supported the EPA's
^position that the standard is based on the best performing
12 percent of sources. One commenter (IV-D-24) noted that the
selection rationale for MACT was inappropriate because the EPA
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established MACT based on lab test data or vendor values rather
than actual control values, which is contrary to the CAA's
language that the emission control level be "achieved in
practice." This sairie commenter also felt that the EPA had not
sufficiently investigated the parameters (emission reductions
achievable, cost of control, and economic impacts) on which the
selection of MACT was based.
Response; Section 112(d)(3) of the Act requires the EPA to
set emission standards for existing sources that are no less
stringent than, but may be more stringent than, the average
emission limitation achieved by the best performing 12 percent of
existing sources. The EPA interprets this passage to clearly
indicate that sources that are meeting this floor level can
potentially be subject to more stringent standards requiring
additional controls. This same section of the Act states that
this "floor" emission limitation shall be set by the
Administrator based on the sources for which the Administrator
has emissions data. For this source category, the EPA surveyed
both industry and vendors to determine the types and approximate
numbers of control systems in use. The EPA did not, however, use
vendor data to establish the emission limit. The proposed
emission limit of 0.013 mg/dscm was based on tests that the EPA
conducted on composite mesh-pad systems operating under normal
process conditions. Lower limits than the one selected were
measured from these devices, but the EPA based the emission limit
on the highest measured data point and believes that this limit
is consistently achievable. (The emission limit in the final
rule has been revised to 0.015 mg/dscm. See discussion in
Section 2.8, Selection of the Emission Limits.) The data cited
by commenter IV-D-58 are based on an older mesh-pad technology
that was tested prior to the new composite mesh-pad designs and
could not be used in setting a standard based on the use of
composite mesh-pad technology.
In setting an emission standard, the Act further directs the
Administrator to take into account the cost, nonaiir quality
health and environmental impacts, and energy requirements in
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establishing these standards. To fulfill this requirement, the
EPA evaluated the cost, impact, and benefit of requiring large
/hard chromium electroplating sources with existing packed-bed
scrubbers to achieve' a level of control corresponding to the use
of a composite mesh-pad system. Requiring all sources to achieve
such a level results in additional emission control of
approximately 1.2 mg/yr, with additional energy requirements of
31,850 megawatt hours per year (MWh/yr) and an additional
38 cubic meters (m3) of solid waste. (These numbers are
nationwide estimates.) The incremental cost effectiveness of
requiring all sources to meet a standard based on composite mesh-
pad systems compared to allowing sources with packed-bed
scrubbers to continue to use these devices is approximately
$4.2 million per Mg of chromium controlled. Although this cost
may seem high, the EPA believes the toxicity of chromium
justifies these costs. The cost analysis for composite mesh-pad
technology accounted for the fact that all composite mesh-pad
designs use either a packed bed or other coarser mesh pad prior
to the composite mesh pad to reduce loading and prevent plugging.
All composite mesh-pad system are single units that combine both
control strategies; thus, the cost analysis was performed on the
whole unit.
Based on the EPA's economic analysis, the requirement that
large, hard chromium electroplaters meet a standard based on
composite mesh-pad technology would not cause adverse economic
effects on large facilities that currently use packed-bed
scrubbers. Due to economies of scale, the relative impacts
(e.g., the percentage increase in electroplating cost) on larger
.facilities are consistently smaller that those on small
facilities. As a result, it will be easier for larger facilities
to pass on control costs. Financial institutions should
recognize this when making decisions concerning whether to grant
icapital to a larger chromium electroplating facility. In
^addition, the capital availability analysis that was done for
small electroplaters indicated that as the revenue of a facility
increases, the ability of the facility to obtain capital also
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increases.. Because larger facilities tend to generate more
revenue, their ability to obtain the necessary capital should be
enhanced. Finally, a larger facility may have more options
available to raise the necessary capital (e.g., internal
financing). (See Chapter 5 of the New Technology Document for a
detailed discussion of EPA's economic analysis for these
systems.)
It is also important to keep in mind that the final rule is
expressed in terms of an emission limit, not a technology. As
discussed in the preamble to the proposed rule, the EPA tested a
system in which a foam blanket was used on a hard chromium
electroplating tank to reduce emissions going to the packed-bed
scrubber. Emissions from the outlet of the scrubber were
measured as 0.008 mg/dscm, which would achieve compliance with
the level of 0.015 mg/dscm required by the final rule for hard
chromium electroplating tanks. Also, a source may retrofit an
existing packed-bed scrubber to add a composite mesh-pad
component, in lieu of replacing the system with a new composite
mesh-pad system.
Comment: Five commenters (IV-F-01 [Sonntag], IV-D-24,
IV-D-27, IV-D-53, IV-D-58) stated that the proposed standard for
small, existing hard chromium electroplaters is too stringent.
Three commenters (IV-F-01 [Sonntag] , IV-D-24, IV--D-58) disagreed
that small existing sources could meet the standeird even if they
were equipped with packed-bed scrubbers. These commenters
questioned the rationale for basing the standard on ideal
conditions, especially when the EPA's own data indicate that
control equipment not operating under these conditions would not
meet the standard. Another commenter (IV-D-53) rioted that the
regulation required even very small sources to install a control
device, which they believed was an undue burden. In lieu of such
a requirement, this commenter proposed that the EPA allow small
sources to use an approved mist suppressant.
Response; The EPA did test some packed-bed scrubber systems
that were not achieving the level of 0.03 mg/dscm required by the
proposed standard. However, these devices were not optimized to
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achieve the higher removal efficiencies. Specifically, when
scrubbers were operated with periodic or continuous washdown in
which fresh water was supplied as makeup to the top of the bed, a
limit of at least 0/03 mg/dscm was achieved. The EPA also notes
that the selection of the emission limit for packed-bed scrubbers
was based on the highest emission level obtained during any of
the tests. The final rule requires the use of fresh water added
to the top of the packed bed whenever.makeup additions occur as
one of the work practice standards identified in Table 2 of the
final rule. Thus, packed-bed scrubbers that are operated in
accordance with the requirements of the rule should be able to
achieve a limit of 0.03 mg/dscm.
As mentioned in a previous response, the emission limit of
0.03 mg/dscm for small, hard chromium electroplaters does not
require these sources to install any particular type of control
equipment. A fume, or mist, suppressant can be used if it meets
the 0.03 mg/dscm emission limit, as could any other control
technique that meets the limit.
In addition, the Agency has considered potential adverse
impacts to small sources by 'requiring a less stringent standard
for small, hard chromium electroplaters than the larger ones, and
by reducing the monitoring, reporting, and recordkeeping
requirements for all sources. (See Sections 2.11 and 2.13,
respectively.)
Comment: Five commenters (IV-F-01 [Schott], IV-D-07,
IV-D-13, IV-D-30, IV-D-39) stated that the proposed standard for
small, existing hard chromium electroplaters was too lenient.
One commenter (IV-D-07) noted that the proper interpretation of
the MACT floor is a straight average, and as such is
0.023 mg/dscm (see discussion in Section 2.5.1). Therefore, the
EPA could not legally establish an emission limit of
0.03 mg/dscm; the appropriate standard is 0.013 mg/dscm (more
Astringent than the floor level of 0.023 mg/dscm).
Two other commenters (IV-F-01 [Schott], IV-D-39) indicated
that the risk remaining after the proposed MACT was applied to
small sources warranted more stringent controls, and that the
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residual risk analysis to be conducted 8 years after the standard
would necessitate a more stringent standard. Two commenters
(IV-D-13, IV-D-30) thought that the EPA's rationale for selecting
MACT for small, hard chromium electroplaters was flawed from both
a technical feasibility and cost basis. One of these commenters
(IV-D-30) stated that packed-bed scrubbers are an inappropriate
design improperly evolving from vapor/liquid mass transfer and
are not good controls for mist elimination. The other commenter
(IV-D-13) stated that the EPA's cost-effectiveness rationale is
flawed because it overstates the cost of retrofitting packed-bed
scrubbers, as well as the efficiency of these devices; the
efficiency is actually 97 percent, not 99 percent.
Response; As discussed in Section 2.1, NESHAP Decision
Process, the Agency believes that the MACT floor is properly
based on the median level of control (use of packed-bed
scrubbers) for the hard chromium electroplating source category.
The Agency considers any discussion of the residual risk
from small, hard chromium electroplaters to be premature at this
time. Under the Act, standards are first set based on control
technology; risk is considered as a factor when deciding to
regulate area sources with a MACT or a GACT standard. Following
the establishment of technology-based standards, the Act has
provisions to set risk-based standards if the residual risk
remaining after implementation of the standard is determined to
be significant. In developing the technology-based standard for
sources that emit hexavalent chromium (a known csircinogen) and
trivalent chromium, the EPA regulated sources with MACT to ensure
that a residual risk analysis will be conducted. Currently, the
EPA has insufficient information to determine if the residual
risk remaining after the implementation of the standard will
warrant development of a risk-based standard.
The EPA also considers its cost analysis for small, hard
chromium electroplaters to be sound. As stated in a response to
a previous comment, the EPA based its retrofit costs on
information from vendors who supply the equipment to the
industry. Commenter IV-D-13 may be correct in stating that
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vendors receive equipment for a lower cost than indicated in the
proposal preamble, but the costs incurred by affected sources are
the costs charged by vendors.
The EPA disagrees with the assertion that packed-bed
scrubbers are not good controls for mist elimination. While
composite mesh-pad systems may be superior technology, packed-bed
scrubbers have been tested by the EPA and can consistently
achieve emission limits of 0.03 mg/dscm, which represents a
99 percent reduction from uncontrolled emissions in a typical
situation. The EPA recognizes the shortcomings in expressing the
control efficiency as an indication of a technology's efficiency,
which is why percent reduction was not chosen as the format of
the standard. The control efficiency of any particular device
varies according to the inlet loading such that any one device
may only achieve an efficiency of 97 percent or less; however, if
the scrubber is properly operated and maintained, the emission
level of 0.03 mg/dscm can still be achieved at the outlet.
Comment: Two commenters (IV-D-41, IV-D-61) asked for
clarification on various aspects of the rule. One commenter
(IV-D-41) wanted to know if MA.CT was at least equivalent to BACT
established by the California Air Resources Board (GARB), which
requires 95 percent control (or a maximum emission rate of
0.15 mg/amp-hr) for small facilities; a 99.8 percent efficiency
(or a maximum emission rate of 0.006 mg/amp-hr) for sources
emitting greater than 10 Ib/yr with controls; and a 99 percent
control (or a maximum emission rate of 0.03 mg/amp-hr) for all
other sources. This commenter felt that if the proposed standard
was not equivalent to 99 percent control, it could not be MACT.
This same commenter noted that the proposed standard does not
meet health risk-based ambient guidelines. According to this
commenter, a hard chromium electroplating source emitting
0.03 mg/dscm of hexavalent chromium exceeds New York's ambient
"-guideline concentration of 2 x 10"5 ug/m3 by two orders of
^magnitude. Finally, this commenter,requested clarification on
the control technology that forms the basis for MACT. This
commenter questioned whether the proposed standard of
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0.013 mg/dscm for hard chromium electroplating represents the use
of mist suppressant controls plus scrubbers with high-efficiency
mist eliminators, or can it be achieved using a four-stage
high-efficiency fiber mist pad air cleaning system. A second
commenter (IV-D-61) noted that the proposed rule was unclear as
to whether the air pollution control device must operate 24 hr/d,
or only during tank operation.
Response: The EPA cannot state whether the final NESHAP for
this source category is equivalent to the GARB standards. The
format of those standards is mg/amp-hr, which is not directly
comparable to the concentration-based format of the this rule.
(See discussion in Section 2.7, Selection of the Format of the
Standard.) A source that operates at a high amperage may achieve
a limit expressed in terms of mg/amp-hr, yet may be emitting high
levels of chromium in terms of the concentration (mg/dscm).
The basis for MACT for small and large hard chromium
electroplaters is packed-bed scrubbers and composite mesh-pad
systems, respectively. When typical inlet conditions are
assumed, packed-bed scrubbers can control 99 percent of emissions
from hard chromium electroplating sources while composite mesh-
pad systems can control up to 99.8 percent. However, as noted
above, control efficiencies can vary from system to system. Also
as noted above, even though MACT was based on the use of specific
controls, any control technique can be used to meet the standard
as long as it is demonstrated through performance testing.
In terms of meeting health risk-based standeirds, MACT
standards developed in accordance with section 112(d) of the Act
are technology-based, not risk-based. The EPA considered risk
for this source category by regulating all area sources covered
by these standards with MACT. Thus, an analysis will be
conducted in accordance with section 112 (f) to determine the
residual risk from these sources.
In response to the second commenter, the final rule has been
clarified to require control of chromium emissions only during
tank operation; tank operation has also been defined.
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Comment: One commenter (IV-D-39) suggested that the
proposed rule should specify ventilation system design to prevent
excess fugitive emissions or dilution, or the EPA should issue
guidance concerning this to the States.
Response; Based on EPA's experience, hard chromium
electroplating sources have to adhere to strict OSHA standards to
protect workers at these facilities. Hard chromium
electroplating tanks must be properly ventilated in order to meet
OSHA and, as such, the EPA does not think it is necessary to
include ventilation guidelines in the MACT standards as well.
The OSHA requirements specify that the exposure level to workers
not exceed 0.05 mg/m3 over a normal 8-hour workday and a 40-hour
work week for water soluble hexavalent chromium. As explained in
the preamble to the proposed rule, one concern with a
concentration standard is that dilution of the exhaust gases can
occur. Possible dilution of the exhaust can be checked by
regulators by comparing the air flow measured during testing with
the design air flow specified for the system in the source's
construction or operating permit, or in manufacturer's
specifications. Such a circumvention of the standard is also
expressly prohibited by § 63.4(b) of the General Provisions;
dilution of the air stream would cause a source owner or operator
to be subject to enforcement action.
2.6 SELECTION OF MACT FOR DECORATIVE 'CHROMIUM ELECTROPLATING AND
CHROMIUM ANODIZING TANKS
2.6.1 Decorative Chromium Electroplating--Trivalent Chromium
Electroplating Process
Comments: Two commenters (IV-D-10, IV-D-43) stated that the
preamble to the proposed rule should have a more detailed
discussion of how the MACT floor for this subcategory was
determined.
Eleven commenters (IV-F-01 [Altmayer, Sonntag], IV-D-01,
IV-D-02, IV-D-03, IV-D-22, IV-D-25, IV-D-53, IV-D-58, IV-D-59)
• .questioned why the EPA was including those decorative chromium
tanks that use a trivalent chromium process in the proposed rule;
these commenters do not believe this process should be regulated.
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Many_of the commenters (IV-D-01, IV-D-03, IV-D-25, IV-D-53,
IV-D-58, IV-D-59) felt that the EPA's decision to regulate
triyalent chromium based on its risk was flawed, and that the EPA
had insufficient data to reach this conclusion. Two commenters
(IV-F-01 [Altmayer], iv-D-58) pointed out that trivalent chromium
baths meet OSHA requirements without ventilation. One of these
commenters (IV-D-58) provided an epidemiological study discussing
the toxicity of chromium. This same commenter stated that the
toxicity of trivalent and hexavalent chromium should be
considered separately when addressing health effects and
determining whether to regulate all sources under MACT. Four
commenters (IV-F-Ol [Altmayer], IV-D-02, IV-D-22, IV-D-58)
questioned why the EPA once considered requiring trivalent
chromium baths for new sources and are now regulating them
equally with hexavalent chromium baths. Finally,, three
commenters (IV-D-01, IV-D-03, IV-D-53) stated that use of the
trivalent chromium process should be encouraged by the EPA, not
discouraged through regulation, because trivalent processes
result in less total chromium in process wastewater and less
sludge generation.
Four commenters (IV-F-01 [Altmayer], IV-D-22, IV-D-25,
IV-D-58) found fault with the data supporting the EPA's reasoning
for regulating trivalent chromium baths. The commenters noted
that the level of hexavalent chromium identified by the EPA from
a trivalent chromium bath (0.004 mg/dscm) would require that
hexavalent chromium be present in the bath at a level of
8 percent. The commenters point out that the presence of only a
few parts per million (ppm) of hexavalent chromium in a trivalent
bath will destroy the bath; this suggests that the presence of
hexavalent chromium was due to analytical integrity.
There were ten comments (IV-F-01 [Bortoli, Sonntag],
IV-D-01, IV-D-02, IV-D-03, IV-D-22, IV-D-25, IV-D-26, IV-D-58,
IV-D-59) concerning specific requirements of the proposed
regulation. These commenters pointed out that the reporting,
recordkeeping, and monitoring requirements eliminate the
incentive for facilities to switch to a trivalent chromium
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electroplating process; according to the preamble, the "no
action" alternative proposed by the EPA will result in
$1.6 million in reporting and recordkeeping. One commenter
(IV-D-22) stated that the EPA recognizes that adding just wetting
agents alone to a trivalent chromium bath can jeopardize the
operation; this commenter questioned why the monitoring and
reporting is necessary. Another commenter (IV-D-59) questioned
how this burden can be justified in light of the fact that
sources using a trivalent chromium electroplating process
comprise only 10 percent of the decorative chromium
electroplating subcategory, and they already have significant
regulatory burden due to Clean Water Act requirements. Two
commenters (IV-D-01, IV-D-03) noted that facilities using the
trivalent chromium electroplating process are already using fume
suppressants and should therefore not be regulated further. One
commenter (IV-F-01 [Sonntag]) suggested regulating trivalent
chromium electroplating processes under GACT to eliminate some, of
the burden.
One commenter (IV-D-02) asked for clarification on the
proposed regulation. This commenter asked whether sources using
the trivalent chromium electroplating process have to meet both
the compliance monitoring and the operation and maintenance
requirements in the proposed rule if they employ only fume
suppressants and not an air pollution control device. The same
commenter also stated that although the EPA had previously
indicated that this was not the intent, the proposed rule is
written such that sources have to meet both the surface tension
limit and an emission standard.
Twelve commenters responded to the EPA's request for comment
on whether the trivalent chromium electroplating process should
be required for new sources. Two commenters (IV-D-01, IV-D-03)
thought that this would be reasonable in situations where the
process would be technically feasible. However, the remaining
-ten commenters (IV-F-01 [Sonntag], IV-D-09, IV-D-10, IV-D-22,
IV-D-26, IV-D-29, IV-D-40, IV-D-43, IV-D-57, IV-D-59) did not
think that this should be a requirement. Four commenters
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(IV-D-26, .IV-D-29, IV-D-57, IV-D-59) did not think that the
process was technically feasible for the full range of decorative
chromium electroplating. One of these commenters pointed out
that decorative chromium platers using a trivalent chromium bath
need stringent process controls and possible proprietary
processes to achieve a finish comparable to a chromic acid bath.
Three commenters (IV-D-22, IV-D-26, IV-D-29) stated that
requiring a trivalent chromium electroplating process for new
sources would force manufacturing overseas, and that this problem
is accentuated by a narrow source definition in which each tank
is considered a source. Two commenters (IV-D-10, IV-D-59)
pointed out inconsistencies in the EPA's reasoning; the EPA can
only require trivalent chromium baths if it recognizes the
difference in toxicity between hexavalent and trivalent chromium.
In the preamble to the proposed rule, the EPA discusses the
adverse environmental impacts of trivalent chromium, but then
suggests requiring this process for new sources. Finally, one
commenter (IV-D-40) suggested that it is not necessary to require
the trivalent chromium process for new sources as long as other
requirements are met, and the source demonstrates that the
residual risk is negligible.
Response: The EPA has reconsidered the requirements
associated with regulation of decorative chromium electroplating
tanks using a trivalent chromium electroplating process.
Specifically, the EPA has examined the technical basis for
including these tanks in the rule and the technical feasibility
of requiring such a process for new sources.
During development of the proposed standards, the EPA
evaluated the trivalent chromium electroplating process and
considered requiring this process for all new decorative chromium
electroplating tanks. The trivalent chromium electroplating
process is considered to be a pollution prevention alternative.
Chromic acid is not present in the plating solution in the
trivalent chromium processes, and hexavalent chromium is regarded
as a bath contaminant in these processes. In addition, all of
the trivalent chromium plating solutions with which EPA is
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familiar contain a wetting agent as an inherent bath component.
That is, the wetting agent is part of the plating solution
purchased from the vendor; it is not added separately by the end
user.
With a trivalent chromium electroplating process, the
potential emissions of chromium in any form are much lower
because the concentration of total chromium in trivalent chromium
baths is approximately four times lower than the total chromium
concentration in chromic acid baths. Trivalent chromium .
processes greatly reduce emissions of the most potent form of
chromium (hexavalent), and significantly lower emissions of
chromium in other forms. In addition to reduction of air
emissions, the use of trivalent chromium processes results in
lower chromium concentrations in process wastewaters and,
consequently, reduces the amount of sludge generated. Based on a
source test conducted by the EPA,'hexavalent chromium emissions
were present at a concentration of 0.004 mg/dscm, and total
chromium emissions were present at an average concentration of
0.023 mg/dscm. Total chromium emissions from a trivalent
chromium bath are approximately 99 percent less than those from a
traditional, uncontrolled decorative hexavalent chromium bath.
Hexavalent chromium emissions are approximately equivalent to
those emitted from a hexavalent chromium bath using a wetting
agent.
Although chromium emissions from the trivalent chromium
process were low, the EPA had not anticipated the presence of
hexavalent chromium in emissions from the trivalent
electroplating process nor the level of total chromium emissions.
.Given that the Act lists all forms of chromium on the HAP list,
the EPA considered the trivalent chromium electroplating process
as a source of chromium emissions as well as an emission control
alternative for the chromic acid electroplating process. Based
on the emission test results, a decorative hexavalent chromium
bath controlled by adding a wetting.agent had equivalent
hexavalent chromium emissions and less total chromium emissions
than a trivalent chromium plating bath. (As previously stated,
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for trivalent chromium baths, the wetting agent is inherent to
the solution; it does not need to be added by the user.) In
addition, the trivalent chromium process may not be technically
feasible for all decorative chromium applications. Therefore,
the final rule does not require the use of a trivalent chromium
electroplating process for either existing or new decorative
chromium electroplating tanks.
Commenters indicated that the levels of hexavalent chromium
emissions identified in the EPA test results must be erroneous
because levels such as these would have contaminated the
trivalent chromium plating bath. Therefore, it is not clear
whether the EPA data accurately reflect emissions from the
trivalent chromium electroplating process or if the analytical
integrity of the data is suspect. In addition, no additional
control measures beyond the use of the wetting agent in the bath
were identified for trivalent chromium processes. Therefore, in
light of the ambiguity of the air emissions data from trivalent
chromium process and the other environmental benefits-of the
trivalent chromium process (less wastewater and sludge
generated), the EPA has decided to regulate these baths
differently from hexavalent chromium electroplating baths. The
EPA has revised the final rule so that users of trivalent
chromium baths are required only to submit initial notifications
certifying that a trivalent chromium bath is being used, and to
keep records of bath chemicals purchased. Subsequent
notifications are required only if the process is changed, or if
a new trivalent chromium process is introduced.
The final rule does make a distinction between types of
trivalent chromium electroplating baths. The minimal
notification and recordkeeping requirements apply only to those
trivalent chromium baths that incorporate a wetting agent. The
EPA has evaluated baths with this characteristic and found them
to have the environmental benefits discussed above. However, the
EPA cannot be certain that a trivalent chromium bath will not be
developed that does not contain a wetting agent as a bath
ingredient. Therefore, the final rule regulates trivalent
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chromium baths that do not incorporate a wetting agent in the
same manner as decorative chromium baths using a chromic acid
solution. The EPA believes that this will discourage the use of
a trivalent chromium bath that does not have a wetting agent as
an inherent bath component.
2.6.2 Decorative Chromium Electroplaters--Chromic Acid
Electroplating Process
Comment: Three commenters questioned the EPA's rationale
for setting the MACT floor for this subcategory. Two commenters
(IV-D-10, IV-D-43) thought more rationale was required to explain
why the use of fume suppressants in conjunction with a packed-bed
scrubber was not a more stringent control option than fume
suppressants alone, and thus, the MACT floor for new sources.
Another commenter (IV-D-50) stated that the EPA's standard
development process ignored the 12 percent criteria set out in
section 112(d)(2) of the Act in setting a standard for
2,800 decorative chromium electroplaters.
Response: The EPA received surveys from 63 decorative
chromium electroplating operations, which had a total tank
population of 102 decorative chromium electroplating tanks. .In
.addition, 11 decorative chromium electroplating operations were
visited. Section 112(d)(3) instructs the EPA to establish the
minimum emission limitation (i.e., the MACT floor) based on the
average emission limitation achieved by the best performing
12 percent of the existing sources for which the Administrator
has emissions information (emphasis added). The EPA recognizes
that the decorative chromium electroplating source category is
large, but is directed to use the information available in
establishing the MACT floor for the source category.
Through analysis of this background information, the EPA
concluded that approximately 15 percent of decorative chromium
electroplating operations were uncontrolled, 40 percent use fume
suppressants, 40 percent use fume suppressants in conjunction
with packed-bed scrubbers, and 5-percent use only packed-bed
scrubbers. Source testing was conducted to establish the
effectiveness of the fume suppressants used by sources in this
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source category. Wetting agent-type fume suppressants were found
to result in outlet concentrations ranging from 0.001 mg/dscm to
0.003 mg/dscm. Foam blanket fume suppressants were found to
result in outlet concentrations ranging from 0.003 mg/dscm to
0.007 mg/dscm. Although tests were not conducted on sources
using packed-bed scrubbers in conjunction with fume suppressants,
the EPA does not think that in this application the packed-bed
scrubbers provide any significant additional environmental
benefit. When packed-bed scrubbers are installed on decorative
chromium electroplating tanks, they are typically used as
evaporators to reduce the wastewater treatment burden. Rinse
waters (contaminated with chromium) are recirculated through the
scrubber until their volume is reduced. The inlet concentration
to a scrubber used for a tank that is already controlled with
fume suppressants would be very small. Likewise, the particle
size of any remaining pollutants is small. These factors combine
to make any additional contaminant removal in the scrubber
difficult. There are insufficient data available to quantify any
improvement in overall emissions; therefore, the EPA based the
MACT floor on the use of fume suppressants alone.
Comment: Two commenters asked for clarification of the
proposed standard. One commenter (IV-D-41) noted that the
standard does not meet health risk-based ambient guidelines. For
example, a source emitting 0.003 mg/dscm of hexavalent chromium
exceeds New York's ambient guideline concentration of 2 x 10"5
*3
ug/m by an order of magnitude. This same commenter requested an
explanation on how the proposed rule compares to BACT established
by GARB, which requires a 95 percent control efficiency or a
0.15 mg/amp-hr emission limit. The second commenter (IV-D-45)
suggested that § 63.342(b)-(d) be clarified; as it is currently
written, the rule assumes that either an air pollution control
device or fume suppressant will be used, and uncontrolled tanks
can remain uncontrolled.
Response: As explained in a previous response in
Section 2.5, Selection of MACT for Hard Chromium Electroplating
Operations, MACT standards developed in accordance with
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section 112(d) of the Act are technology-based, not risk-based.
The EPA considered risk for this source category by regulating
•all area sources with MACT standards. Thus, an analysis will be
'conducted in accordance with section 112 (f) to determine the
residual risk that remains from area sources. If considerable
risk is found to remain, the source category can be subjected to
residual risk standards.
The EPA cannot state whether the.final NESHAP for this
source category is equivalent to the BACT standards established
by GARB. The format of the CARS standards is mg/amp-hr, which is
not directly comparable to the concentration-based format of this
rule. A source that operates at a high amperage may achieve a
limit expressed in terms of mg/amp-hr, yet may be emitting high
levels of chromium in terms of the concentration (mg/dscm). The
basis for MACT for decorative chromium electroplating tanks is
the use of fume suppressants. Data indicate that when these fume
suppressants are used according to manufacturers recommendations,
control efficiencies of greater than 99.5 percent are-achieved.
Sections 63.342(c) and (d) of the final rule express
standards in terms of an emission limit and a surface tension
limit. The rule has been clarified to state that the emission
limit applies to all sources, regardless of the control method
used (if any). Sources using wetting agent-type fume
suppressants to meet the standard are allowed to demonstrate
initial compliance by measuring surface tension if the criteria
of § 63.343(b)(2) are met. This compliance method has been
allowed because it is the EPA's experience that sources
performing decorative chromium electroplating and chromium
anodizing may not have ventilation stacks to the atmosphere,
making source testing impractical.
Comment; Two commenters suggested changes to the proposed
rule. One commenter (IV-F-01 [Sonntag]) proposed that decorative
chromium electroplaters using either a chromic acid or trivalent
•chromium bath be regulated by GAGT. Another commenter (IV-D-41)
suggested that the rule contain specific ventilation design
criteria because the efficiency of mist suppressants is highly
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variable. This commenter proposed that the rule require
high-efficiency slot exhaust designed in accordance with the
specifications in the American Conference of Governmental
Industrial Hygienists industrial ventilation manual, with the use
of high efficiency air cleaning equipment and high efficiency
de-misters capable of 99 percent control.
Response: The EPA does not believe that it is appropriate
to regulate new or existing area sources performing decorative
chromium electroplating operations with GACT due to the toxicity
of chromium compounds and the availability of control techniques.
(See discussion in Section 2.4.) As discussed in Section 2.6.1,
regulation of sources using the trivalent chromium electroplating
process has been revised such that the regulatory burden for
sources using a trivalent chromium bath that incorporates a
wetting agent has been substantially reduced. However, as
discussed in Section 2.4, regulation by MACT is appropriate given
the toxicity of chromium compounds in general. Also, the
technologies that form the basis for MACT are widely available
and will not cause undue burden on any source.
Regarding the suggestion that ventilation specifications be
added to the rule, the EPA believes that this is unnecessary
because sources covered by this standard are also covered by OSHA
guidelines. If a fume suppressant, or any control technique, is
not properly operated such that workers are being exposed to
chromic acid fumes, the source is in violation of OSHA. In
addition, the EPA has established monitoring techniques that
would ensure that the chromium electroplating or anodizing
processes are operated properly at all times with appropriate
fume suppressants. Therefore, it is the EPA's opinion that to
specify ventilation requirements in this rule would be redundant.
Comment; Three comments pertained specificailly to the
proposed emission limit of 0.003 mg/dscm. One commenter
(IV-D-58) proposed that sources that choose to use an air
pollution control device in lieu of fume suppressants be allowed
to meet a limit of 0.03 mg/dscm. Two commenters (IV-D-50,
IV-D-58) did not think that a source using either a fume
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suppressant or a. fume suppressant in conjunction with a
packed-bed scrubber could consistently meet a limit of
0.003 mg/dscm. One of these commenters (IV-D-50) supplied test
results to support this claim. One commenter (IV-D-09) requested
further justification for the 0.003 mg/dscm proposed standard;
this commenter noted that the EPA had previously proposed a level
of 0.01 mg/dscm.
Response: As a result of comments received at proposal, the
EPA has reconsidered the emission limit of 0.003 mg/dscm for
decorative chromium electroplating and chromium anodizing tanks.
As stated in the preamble to the proposed rule, this emission
limit was based on tests of a decorative chromium electroplating
^
tank in which a combination wetting agent/foam blanket was used
to control emissions. Tests had also been conducted on a
decorative chromium electroplating tank using only a foam blanket
for control. The analytical data for all types of fume
suppressants ranged from 0.001 to 0.007 mg/dscm, with the wetting
agent/foam blanket data ranging from 0.001 to 0.003 mg/dscm and
the foam blanket data ranging from 0.003 to 0.007 mg/dscm. At
one time, the EPA had considered (but had never proposed) an
emission limit of 0.01 mg/dscm which was based on applying a
safety factor to the highest measured emission limit
(0.007 mg/dscm) in the data base. After further consideration,
the EPA did not include the foam blanket data when setting the
proposed emission limit because it was thought that these data
may indicate that foam blankets are less effective than wetting
agents in reducing chromium emissions.
In evaluating whether the proposed emission limit of
•0.003 mg/dscm should be revised in the final rule, the EPA
reassessed the effect the test methods may have had on the
emission data obtained. The analytical method used for the fume
/
suppressant test was colorimetric spectroscopy. As more
,: efficient control technologies (such as composite mesh-pad
systems) were developed, a more-sensitive analytical method was
needed to measure the lower concentrations of chromium being
emitted. Therefore, the more sensitive ion chromatography method
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was used in the later phases of emission testing for these
standards involving add-on control devices. By using the less
sensitive colorimetric analytical method, it is unclear whether
the variation found between the two types of fume suppressants
was due to a performance difference in the fume suppressants or
was an artifact of the analytical method used. The fact that
there is overlap between the foam blanket and wetting agent/foam
blanket data (that is, one foam blanket test resulted in the same
emission limit as one of the wetting agent/foam blanket tests
[0.003 mg/dscm]) further indicates that this could be the case.
Therefore, the EPA concluded that the emission limit in the final
rule should be based on the performance of both foam blankets and
wetting agents. Accordingly, the emission limit selected for
decorative chromium electroplating and chromium anodizing tanks
in the final rule is 0.01 mg/dscm. This emission limit was
selected by applying a safety factor to the highest measured data
point (0.007 mg/dscm) to account for variation in the sampling
and analytical procedures. The selection of this emission limit
is consistent with the methodology used to select emission limits
based on other control techniques. (See discussion in
Section 2.8, Selection of Emission Limits.)
2.6.3 Chromium Anodizing Operations
Comment: Three commenters (IV-D-14, IV-D-47, IV-D-58)
questioned the MACT floor established by the EPA for sources
performing chromium anodizing. Two commenters (IV-D-47, IV-D-58)
stated that it did not appear that the EPA had sufficient data to
perform a MACT floor analysis for these sources, and that the
final rule should not include a MACT standard for chromium
anodizing sources unless additional data are gathered or higher
emission rates are allowed. The third commenter (IV-D-14) noted
that the emission limit for the top 12 percent is surprisingly
low and should be reevaluated. Alternatively, this commenter
suggested that anodizing tanks in the aerospace industry be
considered a separate subcategory because fume suppressants are
not always feasible. Another commenter (IV-G-01) also stated
that chromium anodizers, as well as decorative chromium
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electroplaters, that cannot use fume suppressants should be
considered separately. This commenter states that the MACT floor
for such sources should be based on packed-bed scrubbers.
Response; The TVIACT floor for existing chromium anodizing
sources was based on information available to EPA on the source
category. Information on the industry was obtained through
survey questionnaires to both industry representatives and
control system vendors, site visit reports, and available
emission data. Although information was not available from all
sources in the category, EPA believes the information was
sufficient to satisfy the requirements of section 112(d)(3) of
the Act. The industry survey, which included some aerospace
facilities, indicated that fume suppressants were the control
technique predominantly used in the industry. Data based on
tests at decorative chromium electroplating tanks were used to
establish the efficiency of fume suppressants; in that sense,
data was transferred from one source category to another. As
stated in the previous response, the emission limit associated
with fume suppressants has been raised from 0.003 mg/dscm to
0.01 mg/dscm. No technical reason was provided by industry, nor
is one known by the EPA, for creating a separate subcategory of
sources for which fume suppressants are not technically feasible.
Thus, all new and existing sources performing chromium anodizing
must meet an emission limit of 0.01 mg/dscm (or maintain the
surface tension specified in the rule).
Comment: Six commenters (IV-D-14, IV-D-17, IV-D-36,
IV-D-44, IV-D-47, IV-D-58) did not think that the standard for
chromium anodizing tanks was achievable in all situations,
especially when an add-on control device was used in lieu of fume
suppressants. Two commenters (IV-D-47, IV-D-58) cited test data
to support this claim. One commenter stated that tests of
.sources in the SCAQMD indicate that a level of 0.003 mg/dscm is
-not consistently achieved by using fume suppressants (IV-D-58).
-Test data were provided by commenter IV-D-47 for sources
performing chromium anodizing and using add-on controls. One
commenter (IV-D-58) suggested that the standard for chromium
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anodizing tanks controlled with add-on control devices be set at
0.03 mg/dscm. Otherwise, this commenter believes that sources
will have to use an air pollution control device followed by a
state-of-the-art fiber-bed mist eliminator.
Response: The MACT floor for existing and new chromium
anodizing sources is based on the use of fume suppressants. The
EPA selected this technology as the basis for MACT for all
existing and new sources. The emission limit associated with the
use of fume suppressants has been established as 0.01 mg/dscm in
the final rule. Section 112(d)(3) of the Act prohibits the EPA
from establishing a standard that is any less stringent than the
MACT floor for a category or subcategory of sources. The EPA has
explored the possibility that sources performing decorative
chromium electroplating and chromium anodizing operations that
cannot use fume suppressants may constitute a separate
subcategory. Thus, a separate MACT floor would be established
for the subcategory, and MACT selected based on ci cost-benefit
analysis of selecting a standard more stringent than the floor
for this subcategory. However, as discussed in Section 2.6.2 for
decorative chromium electroplaters, the EPA could not establish
that a distinct subcategory based on the technical infeasibility
of fume suppressants existed within the chromium anodizing source
category. The EPA was informed by commenters thait fume
suppressants were not feasible for all operations, but
information was not provided on the technical recisons for this.
For instance, two commenters alluded to the fact that fume
suppressants may not be feasible for adhesive bonding
applications because corrosion protection failure* may result from
the change in bath chemistry. However, in a follow-up letter,
one of these commenters conceded that other factors may have
caused corrosion failures. Due to the lack of data, the EPA
could not conclusively state that there is a separate subcategory
for which fume suppressants are not technically feasible.
The data submitted by commenter IV-D-47 were evaluated by
EPA to determine the performance level of scrubber systems
controlling emissions from chromium anodizing tanks. Post-
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control emissions from the four scrubbers for which there were
data range between 0.0026 and 0.033 mg/dscm. One of the scrubber
systems met the proposed limit of 0.003 .mg/dscm; two of the four
scrubber systems would meet the emission limit of 0.01 mg/dscm in
the final rule. The operation and maintenance practices
associated with the systems tested are not known. Implementation
of the work practice standards in § 63.342(f) may result in all
systems achieving a level of 0.01 mg/ciscm.
The EPA believes that the revised emission limit of
0.01 mg/dscm in the final rule makes it easier for sources to
comply using add-on control technology. Also, commenters
indicated that they would like to use fume suppressants but would
need time to test the feasibility of the fume suppressants for
their application, and in the case of government contractors,
obtain permission for their use. The EPA believes that the
extended compliance time of 2 years for the chromium anodizing
source category will allow sources more time to explore the
possibility of using fume suppressants. Also, this timeframe
will allow sources that prefer to use air pollution control
devices time to optimize their systems.
Comment: There were four comments related to the efficiency
of fume suppressants in chromium anodizing tanks. Three
commenters (IV-D-01, IV-D-03, IV-D-43) stated that allowing fume
suppressants for the control of large chromium anodizing tanks
should be reevaluated; some tanks are very large and may require
more control. One of these commenters supplied source test data
to support this statement. Another commenter (IV-D-47) indicated
that the EPA had overstated the control efficiency of fume
suppressants; the commenter felt that the control efficiency was
closer to 95 percent. Based on an uncontrolled emission rate of
2.59 x 10~4 gr/dscf, a control efficiency of 99.5 percent would
be needed to meet the proposed standard.
Response; The EPA did not propose a standard expressed in
terms of control efficiency for the very reason cited by
commenters; the efficiency of fume suppressants vary according to
the electroplating or anodizing tank operation. Based on source
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tests conducted by the EPA, fume suppressants used on "typical"
decorative chromium electroplating tanks in accordance with
manufacturers specifications can reduce over 99.5 percent of
emissions when compared to an uncontrolled tank. The outlet
concentrations measured during these tests ranged between
0.001 and 0.007 mg/dscm. If the uncontrolled tank had lower
emissions, the same controlled outlet concentration could result
but the overall efficiency would be lower. Thus, this rule
requires sources to measure an outlet concentration, not a
control efficiency.
The emission limit for chromium anodizing tanks was based on
tests of decorative chromium electroplating tanks in which fume
suppressants were used. However, the EPA believes that the final
emission limit of 0.01 mg/dscm is appropriate for both decorative
chromium electroplating and chromium anodizing operations. In
response to the commenters that were concerned that the use of
fume suppressants was not sufficiently stringent for large
chromium anodizing tanks, data available to the EPA indicate that
an uncontrolled chromium anodizing tank has total chromium
emissions typically ranging from 0.54 to 1.6 mg/dscm, with an
average of 0.97 mg/dscm. These uncontrolled emission rates are
similar to those seen for decorative chromium electroplating (see
Chapter 3 of the Proposal BID). Therefore, the EPA believes that
fume suppressants will be equally effective for both chromium
anodizing and decorative chromium electroplating tanks.
Comment; One commenter (IV-D-14) stated that sources should
have the option of using reducing agents in wet scrubbers to
convert hexavalent chromium to trivalent chromium.
Response: Both the proposed and final rules regulate
chromium compounds, not just hexavalent chromium. Therefore,
using a reducing agent to change the form of the chromium from
hexavalent to trivalent is not allowed by the final rule.
Comment; There were two comments related to the impact of
the proposed regulation. One commenter (IV-D-14) stated that in
the impact analysis the EPA erroneously assumed that all sources
can use fume suppressants to meet the standard. Because this is
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not the case, the analysis should include costs for emission
control equipment. Another commenter (IV-D-47) was concerned
that the EPA had underestimated the impact of the rule on small
sources performing chromium anodizing to support the aerospace
industry. To minimize the impact, this commenter suggested a
reduction in monitoring and recordkeeping for small sources.
Response; In calculating impacts for the proposed rule, the
EPA did assume that all sources performing decorative chromium
electroplating and chromium anodizing operations would use fume
suppressants to comply with the rule. The EPA still thinks that
the vast majority of sources will opt to use fume suppressants;
all of the commenters that stated that they could not use fume
suppressants had a control device in place. The industry did not
supply information on the number and types of sources that could
not use fume suppressants. The EPA thinks that there is only a
small portion of the industry that would be unable to use fume
suppressants. Also, the extended compliance time may allow
sources that thought they could not use fume suppressants time to
test additional fume suppressants that may be viable. For these
reasons, the EPA believes that capital expenditures for the
decorative chromium electroplating and chromium anodizing source
categories will be minimal.
Of course, all source categories will experience costs
associated with testing, monitoring, reporting, and record-
keeping. The EPA has revised these requirements to minimize the
burden on area sources. (See discussion of Selection of
Monitoring and Reporting and Recordkeeping Requirements in
Sections 2.11 and 2.13, respectively.)
2.7 SELECTION OF THE FORMAT OF THE STANDARD
Comment: Seven commenters (IV-D-07, IV-D-10, IV-D-41,
IV-D-42, IV-D-47, IV-D-50, IV-D-53) stated that the format of the
standard should be expressed as milligrams of chromium emitted
per amp-hour of operation (mg/amp-hr), not mg/dscm. According to
•-•the commenters, concentration-based standards are flawed because
they can be circumvented by dilution (IV-D-10, IV-D-41, IV-D-53);
concentration can vary from system to system depending on the
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design flow rate (IV-D-io, IV-D-41); and source test data
indicate that outlet concentrations do vary widely over various
inlet conditions (IV-D-07).
Five commenters" (IV-D-10, IV-D-14, IV-D-41, IV-D-47,
IV-D-53) pointed out that California's rule is expressed
as mg/amp-hr and requested that EPA maintain consistency with the
California rule. According to one commenter (IV-D-10), this
request is reasonable because, in general, process emission rate
standards result in lower emissions than the proposed concen-
tration-based standards. Another commenter (IV-D-53) provided
calculations to demonstrate that sources that meet the
concentration limit will also meet California's process emission
rate. Two commenters (IV-D-10, IV-D-14) were concerned that some
well-controlled sources that currently meet the process emission
rate standard would have to install additional controls to meet
the concentration limit. Finally, one commenter (IV-D-41)
pointed out that the California standards address the problem of
residual risk, and the EPA should therefore relate their standard
to the California standard.
Two commenters (IV-D-10, IV-D-50) stated that emissions
should be correlated to production rates because chromium
emissions increase proportionately with increased current;
whereas ventilation air flow is not related to electroplating
bath operation.
One commenter (IV-D-42) stated that a mg/amp-hr format is
the most appropriate because that is the one permitting agencies
will use. Another commenter (IV-D-53) stated that a process
emission rate is readily enforceable and can be verified without
requiring a source test; the commenter did not expand on how this
would be possible.
Two commenters (IV-D-10, IV-D-42) suggested that, at a
minimum, the final rule should recognize process emission rates
as acceptable, and identify acceptable alternatives to avoid an
equivalency evaluation.
Response; The majority of commenters felt that the format
of the standard should be changed from a concentration format to
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a process emission rate format. However, available test data
indicate that a process emission rate format will not ensure that
the control level required by the standard will be achieved
consistently. A comparison of the composite mesh-pad systems and
packed-bed scrubber data sets reveals that there is no overlap in
the concentration data sets; however, there is overlap in the
process emission rate data sets. For example, the most stringent
limit for existing hard chromium electroplaters is 0.015 mg/dscm
and is based on the use of composite mesh-pad systems. The
concentration data on which this emission limit is based ranges
between 0.003 and 0.013 mg/dscm; whereas, the process emission
rates for this same data set varies from 0.002 to
0.090 mg/Amp-hr. The data set associated with the use of
packed-bed scrubbers with periodic or continuous washdown shows a
variation in concentration from 0.021 to 0.028 mg/dscm; the
process emission rates for the same data set vary from 0.068 to
0.219 mg/Amp-hr. A concentration format ensures that the
appropriate control technology is employed because the
concentration data sets are mutually exclusive between the two
technologies. Therefore, a concentration-based format was
selected. This data analysis also refutes one commenter's
statement that process emission rate standards result in lower
emissions than the proposed concentration-based standards. As
evident from the data presented above, both packed-bed scrubbers
and composite mesh-pad systems can achieve similar process
emission rates; however, composite mesh-pad systems are a
superior technology and result in lower emissions than packed-bed
scrubber systems. Because of the data overlaps in the process
•emission rates, the EPA also cannot establish in the final rule
process emission rate limits that would be considered equivalent
to the concentration limits presently in the rule.
Some commenters were concerned that a concentration-based
^standard would be easily circumvented through dilution of the
-.emission stream. The EPA examined concerns over dilution of the
exhaust gases as a means of circumventing the standards prior to
selecting concentration as the format for the standard. In
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considering the effects of dilution, it was determined that the
dilution of the gas stream at the outlet of the control system is
more of a concern than any dilution taking place at the inlet to
the control systems "because the control systems operate as
relatively constant outlet devices. (That is, the concentration
at the outlet is relatively independent of the inlet loading.)
Dilution of the gas stream at the outlet of the control system
can be addressed by a review of the test data arid permit data
from a given facility. The air flow rate measured during testing
should approximate the design air flow rate for the control
system reported on the permit application. If the two values
differ significantly, then an inspection of the control system
can be made to determine if dilution air is being introduced. it
is also possible for a facility to dilute the inlet gas stream to
the control device by designing a system to ventilate the
electroplating tanks at air flow rates substantially above those
required for adequate ventilation. However, the increased costs
associated with heating the room air in the electroplating shop,
supplying additional makeup air, oversizing the control system
for the dilution air, and the increased maintenance cost of such
a system would outweigh the costs of complying with the standard
without dilution. In addition, as stated previously, the control
systems function as constant outlet control devices; therefore,
the introduction of dilution air at the inlet to the control
system would not substantially bias the outlet emission level
except in cases of large volumes of dilution air being added.
Further, § 63.4(b) of the General Provisions expressly prohibits
dilution as a means to comply with an emission limit. Violations
of this provision would cause the EPA to bring an enforcement
action against the owner or operator of the source. Therefore,
concerns of dilution of the air stream were not considered to be
significant enough to warrant changing the format of the
standard.
Other commenters stated that emissions should be correlated
to production rates because chromium emissions increase
proportionately with increased current; whereas ventilation air
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flow is not related to electroplating bath operation. The
.commenters are correct in stating that the production rate, as
measured by ampere-hours, is related to .emissions. However, the
amount of current supplied to the tank is an indicator of the
amount of uncontrolled emissions from the tank, not the
controlled emission level from the tank. As shown previously,
the controlled mass emission rate is not directly related to the
amount of current supplied to the tank. As stated in the
proposal preamble, the process'emission rate is based on the
outlet mass emission rate and the current supplied to the plating
tank. The outlet mass emission rate varies depending on the
chromium concentration and the exhaust gas flow rate. Because
^
the outlet chromium concentration levels do not vary
significantly with the current loading to the plating tank,
facilities that operate at high current loadings would have a
much lower process emission rate that facilities that operate at
low current loadings even though both facilities have applied the
•same control technology and may be controlled to the same
emissions level. Conversely, facilities that have a low process
emission rate could have higher emissions than intended by the
standards because of a high inlet loading (high current loading)
to the control device. Therefore, the EPA does not consider the
use of process emission rates as an appropriate format for the
standard.
One commenter pointed out that because the California
standards address the problem of residual risk, the standard
should be related to the California standard. As mentioned in
previous comment responses, MACT standards are based on the
control technologies used in the industry and risk is not
considered in selecting the level of the standard. However, risk
may be considered in determining whether or not an area source is
regulated with MACT or GACT. Residual risk impacts are addressed
,,when a MACT standard is reviewed as required by section 112 (f) .
Other comments received suggest that a mg/Amp-hr format is
the one permitting agencies will use and that a process emission
rate is readily enforceable and can be verified without requiring
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a source test. Regardless of the format of the standard, all
sources subject to an emission limit would be required to perform
an initial source test to demonstrate compliance. It is unclear
how a process emission rate standard would eliminate the need for
compliance testing. Sources would need to demonstrate compliance
with a standard expressed in terms of mg/Amp-hr; the selection of
the format of the standard does not affect the need for
compliance testing. Further, in all source tests, the
concentration of emissions at the outlet is measured. Other
formats, such as the process emission rate format, build on these
data. Therefore, no additional testing burden is imposed by the
concentration format.
Based on the data collected on this industry, the EPA
believes that a concentration format is the most appropriate
format for this standard. Therefore, no change to the format of
the standard has been made in the final rule.
Comment: Eight commenters (IV-D-10, IV-D-14, IV-D-24,
IV-D-32, IV-D-34, IV-D-47, IV-D-53, IV-D-58) disagreed with the
EPA's decision to base the standard on emissions of total
chromium rather than on emissions of hexavalent chromium. Five
commenters (IV-D-10, IV-D-14, IV-D-24, IV-D-53, IV-D-58)
contended that there are limited data to support the toxicity of
trivalent chromium, and thus to include it in the total chromium
number. Two other commenters (IV-D-32, IV-D-34) stated that data
show that an average of 30 percent of the total chromium will be
trivalent chromium emissions. Two other commenters (IV-D-47,
IV-D-53) agreed, stating that the rule should focus on hexavalent
chromium because hexavalent chromium emissions are lower than
total chromium emissions, and hexavalent chromium is truly the
compound of concern. One commenter (IV-D-53) pointed out that
the EPA Report 68-D-90155 gives the ratio of hexavalent chromium
emissions to total chromium emissions as 85 percent. One
commenter (IV-D-58) explained that hexavalent chromium emissions
are lower than total chromium emissions because hexavalent
chromic acid mist is very reactive and unstable.
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Two commenters suggested alternate compliance methods to
account for the difference between hexavalent and total chromium
'emissions. One commenter (IV-D-47) stated that sources should be
allowed to demonstrate compliance by testing for hexavalent
chromium in lieu of total chromium. Another commenter (IV-D-24)
suggested that if a source exceeds the standards based on its
total chromium emissions, the source should then be allowed to
test for hexavalent chromium to demonstrate compliance.
Response; Several commenters questioned the validity of
basing the standard on total chromium rather than hexavalent
chromium. The EPA selected total chromium because the HAP list
identifies all chromium compounds, not just hexavalent chromium
•»
compounds. In addition, based on testing conducted by the EPA
for these source categories, there is little difference between
total and hexavalent chromium emitted from the processes. The
compound emitted from these electroplating and anodizing baths is
chromic acid, a hexavalent compound of chromium. For tests where
samples were analyzed for both hexavalent and total chromium, it
was shown that, considering the precision of the sampling and
analytical methods used, the hexavalent and total chromium levels
were essentially the same for chromic acid baths (varying within
±10 percent in most instances). In some cases, the hexavalent
chromium amount was more than the total chromium amount as a
result of the higher sensitivity of the hexavalent chromium
analytical technique. Because the EPA data base is mainly
comprised of data measured as hexavalent chromium, the final rule
does allow sources to demonstrate compliance with the total
chromium emission limits through the measurement of either
hexavalent or total chromium for all sources. The final rule
also incorporates acceptable analytical methods for hexavalent
chromium into Methods 306 and 306A.
Comment: One commenter (IV-D-42) suggested that the format
should be flexible because States will also be requiring sources
'to meet health risk-based standards.
Response; A concentration-based format is flexible and
should not interfere with any health risk-based standards set by
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States. During source tests, the concentration of the emission
stream is determined as the building block for other formats.
Therefore, the concentration at the outlet will be known prior to
calculating other formats such as mass rate or process emission
rates.
Comment: One comtnenter (IV-D-16) questioned how compliance
would be determined if tank utilization is low; that is, would
facilities be penalized by inspectors suggesting that sources are
diluting their airflow.
Response: Initial compliance tests must be conducted while
the electroplating tanks are operated at or near maximum
capacity. If a. source can meet the standard under maximum
operating conditions, then the standard would continue to be met
under normal or low tank utilization periods. In addition, the
ventilation rate for any given tank or series of tanks is
determined based on the dimensions and surface area of the
electroplating tank. The ventilation rate remains constant
regardless of the number of parts placed in the tank or tank
utilization. Operating a tank at its ventilation rate under low
utilization periods should not be considered as dilution by an
inspector.
2.8 SELECTION OF THE EMISSION LIMITS
Comment; Two commenters (IV-D-24, IV-D-50) stated that an
insufficient number of production operations were tested for the
EPA to establish an emission limit. One commenter (IV-D-24)
pointed out that out of 5,000 facilities, only 13 hard chromium,
3 decorative chromium, and no chromium anodizing sources were
tested. This commenter suggests that additional tests be
conducted. The other commenter (IV-D-50) concurred that the
EPA's data base is insufficient to support either the numeric
standards or the surface tension limits. This commenter
suggested that the proposed standard be issued as an interim rule
until more data are gathered and a justified standard set. Two
commenters (IV-D-11, IV-D-33) stated that the steindards are based
on false assumptions, not data.
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Response; The EPA believes that the data base of testing
information is suitable for setting the emission limits and
.surface tension limit in the final rule. Section 112(d)(3) of
the Act directs the "Administrator to establish an emission
limitation using the emissions information available. To
establish the level of control appropriate for the source
categories covered by this rule, the EPA surveyed over
120 operations that represented 215 hard chromium electroplating
tanks, 102 decorative chromium electroplating tanks, and
31 chromium anodizing tanks. Additional information was obtained
from site visits to numerous hard and decorative chromium
electroplating and chromium anodizing facilities. The EPA also
*
conducted performance tests at 10 facilities representing 13 hard
chromium and 3 decorative chromium electroplating tanks to
establish the performance level of controls used in the industry.
These test results, not assumptions, were used to establish the
emission limits. Finally, the rule is proposed for public
comment before it is finalized by the EPA and before sources are
required to comply. In response to comments received during this
public comment period, the EPA has further evaluated the emission
limits, and revised them when appropriate as described in
Section 2.6.2 and below.
Comment; Four commenters (IV-F-01 [Schott], IV-D-13,
IV-D-30, IV-D-50) representing three companies stated that the
emission limit should be changed for hard chromium plating
operations. Three commenters suggested changing the emission
limit that is based on the use of composite mesh-pad systems.
One commenter (IV-F-01 [Schott]) stated that the control level
should be based on optimum design, as well as cost, energy
consumption, and environmental impact, and suggested a level of
0.006 mg/dscm. In a subsequent letter (IV-D-13), this same
commenter stated that the EPA did not test the best systems
..-•available and suggested a level of 0.009 mg/dscm, which in the
-EPA's data base is the worst result achieved by the best system.
Another commenter (IV-D-30) agreed that the best systems were not
tested and that the standard as written penalizes companies that
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have installed high-efficiency units. Therefore, this coinmenter
suggested a level of 0.001 mg/dscm to correspond with the use of
composite mesh-pad systems. Finally, one commenter (IV-D-50)
suggested that numeric limits be based on 95 percent removal of
uncontrolled emissions.
Response: The EPA does not think it is appropriate to lower
the emission limit that is based on the use of composite mesh-pad
systems. The commenters did not provide any data to support
their claim that the emission limit consistently achievable with
a composite mesh-pad system is 0.001 mg/dscm, 0.006 mg/dscm, or
0.009 mg/dscm. After meeting with the commenters (IV-D-13,
IV-D-30), the EPA agreed to contact a State agency that the
commenters suggested would have data to support such a limit.
The data were requested, received, and evaluated, but did not
support a lower limit.
As was discussed in Section 2.6.2, the emission limit for
all decorative chromium electroplating tanks and chromium
anodizing tanks at all existing and new sources has been changed
to 0.01 mg/dscm in the final rule. This limit is based on
applying a safety factor to the highest data point
(0.007 mg/dscm) in the fume suppressant data base. Likewise, as
described in the preamble to the proposed rule, the emission
limit that is based on packed-bed scrubbers is based on rounding
the highest value (0.028 mg/dscm) in the packed-bed scrubber data
base to 0.03 mg/dscm to incorporate a safety factor. To be
consistent in setting the emission limit that is based on the use
of composite mesh-pad systems, the emission limit of
0.013 mg/dscm has been changed to 0.015 mg/dscm in the final
rule. As with the other emission limits, this emission limit is
based on applying a safety factor to the highest value
(0.013 mg/dscm) in the data base of information on composite
mesh-pad systems to ensure that the limit is consistently
achievable.
Regarding the suggestion that the numeric limit be based on
a 95 percent control efficiency, for the reasons described in the
preamble to the proposed rule, the EPA does not believe that
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using a percent efficiency format is the best method for
evaluating the performance of control techniques for these source
categories. For the devices expected to be used by sources
covered by these standards, a relatively constant outlet
concentration results. Therefore, percent reduction is not a
good indicator of performance because it depends on the inlet
conditions as well as the outlet conditions. A numeric limit
based on percent reduction could penalize facilities with low
inlet loading, while facilities with high inlet loadings could
meet the 95 percent efficiency but be emitting larger quantities
of chromium. For these reasons, it would also be impossible to
select a numeric limit that is based on a 95 percent control
efficiency.
2.9 SELECTION OF DEFINITION OF SOURCE
Comment; Three commenters (IV-D-06, IV-D-17, IV-D-24)
thought that the proposed source definition did not adequately
address the situation in which multiple tanks are tied to a
single control device. One commenter (IV-D-06) thought that the
manner in which this situation was addressed in the preamble to
the proposed rule was confusing. In a situation with multiple
tanks tied to a common control device, this commenter asked if
compliance would be achieved if emissions from the new tank in
combination with emissions from existing tanks do not exceed the
required emission levels at the exit of the emissions control
system. Two commenters (IV-D-17, IV-D-24) suggested alleviating
the potential confusion by selecting a broader definition of
source for facilities controlling multiple tanks with one control
device. The source could be defined as the population of tanks
connected to a single control system, or a group of tanks
associated with a single electroplating system in a designated
subcategory (i.e., each electroplating line). Alternatively,
when multiple tanks are tied to one control system, new source
. MACT could be triggered if greater than 50 percent of the tanks
existing at the time of proposal have been replaced or added
(IV-D-17). One commenter (IV-D-07) thought the rule should
clarify that.new tanks at existing sources are subject to new
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source MACT even if they are tied into an existing control
system.
Five commenters stated that the source definition is too
narrow; three of these commenters (IV-D-22, IV-D-26, IV-D-59)
suggested that the source be defined as the plant. Commenters
pointed out that a broad definition of source red.uces the
recordkeeping burden (IV-D-26), whereas the narrow definition
results in burdensome compliance testing and monitoring
(IV-D-57). One commenter (IV-G-01) pointed out that a narrow
definition of source will subject a facility to the
preconstruction review requirements of § 63.5, even in the case
of a single tank being added at a major source. One commenter
(IV-D-59) was also concerned that, should the EPA require the use
of trivalent chromium baths as new source MACT, the narrow
definition of source could result in an existing hexavalent
chromium bath having to be replaced by a trivalent chromium bath
once it has been consumed or contaminated.
Response: In the final rule, the affected source continues
to be defined as each chromium electroplating or chromium
anodizing tank. If an additional tank is tied into an existing
control system and the reconstruction criteria are met, that new
tank would have to meet the requirements for new source MACT. As
discussed in Section 2.12.3, the final rule contains procedures
for demonstrating compliance when multiple tanks are controlled
by one control system. Alternately, a source may choose to
control the new or reconstructed tank separately. The EPA
believes that identifying affected sources in terms of the
control strategy used to comply with the standard will make
enforcement of the rule difficult.
The final rule also clarifies the reporting and
recordkeeping requirements for affected sources. In general, the
reporting and recordkeeping requirements-in the final rule would
not vary according to the affected source definition. Regarding
the preconstruction review requirements of § 63.5 of subpart A,
the final rule overrides these requirements in § 63.345.
Section 63.345 of the final rule requires notification of
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construction or reconstruction of an affected source (i.e., the
tank). The EPA believes that this requirement is reasonable
because many tanks are controlled separately, and the permitting
authority will need "information on the control strategy. If the
new or reconstructed tank is to be tied into an existing control
scheme, the requirements of § 63.345 should not be difficult to
fulfill. Also, this section does not require approval for
construction or reconstruction. These activities may begin once
a complete notification of construction or reconstruction is
submitted.
Cojsment: Two commenters (IV-D-07, IV-D-28) suggested that
the discussion of definition of source be clarified. One
commenter (IV-D-07) thought the rule should clarify that the
narrow new source definition applies to new and modified area
sources as well as major sources. The second commenter requested
an explanation of the control requirements if a facility has one
tank controlled with a packed-bed scrubber and then adds another
tank The commenter stated the new tank would obviously require
a composite mesh-pad system for control and questioned whether
controls for the existing tank would also have to be upgraded.
Response: Section 63.340(a) of the final rule states that
the affected source is each hard chromium electroplating,
decorative chromium electroplating, and chromium anodizing tank.
The affected source definition does not differentiate between new
and existing sources, or between major and area sources; the same
affected source definition applies to all sources.
If an existing facility has one tank that is tied to a
packed-bed scrubber and adds another tank to be controlled by a
separate control system, only the new tank would have to be
controlled by a composite mesh-pad system (or some control
technique that achieves an equivalent control level). If the new
tank is to be tied into the existing control device, the new tank
would still need to achieve the higher control level. The
compliance method to be followed in this situation is outlined in
§ 63.344(e) of the final rule.
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2.10 SELECTION OF COMPLIANCE DATES
Comment;: Several commenters stated that the proposed
compliance timeframe of 1 year for hard chromium electroplating
operations is insufficient. The following reasons were given:
1. It is insufficient time to inform and educate
responsible parties, install equipment, and train operators
(IV-F-01 [Altmayer], IV-D-58);
2. More time is needed to account for design, bidding,
installation, and testing (IV-D-17, IV-D-21, IV-D-27, IV-D-44
IV-D-47, IV-D-52);
3. At government installations, more time is needed to
procure funding, submit a control plan, award a contract,
install, and test (IV-D-37, IV-G-01);
4. Sources need time to build up inventories to account for
downtime during retrofit (IV-D-24);
5. Large sources will have large expenditures for the
equipment and personnel necessary to do testing, reporting, and
recordkeeping (IV-D-57);
6. Budgeting, test planning, testing, and results
evaluation will take more than 1 year (IV-D-16); and
7. There may not be a sufficient supply of control devices
for all of the existing sources nationwide (IV-D-47, IV-D-49).
Eight commenters recommended 2 years for compliance
(IV-D-21, IV-D-27, IV-D-37, IV-D-44, IV-D-47, IV-D-49, IV-D-52,
IV-D-57). Five commenters recommended 3 years for compliance
(IV-F-01 [Altmayer], IV-D-17, IV-D-24, IV-D-57, IV-D-58). One
commenter (IV-D-37) suggested having a, tiered compliance
approach, whereby uncontrolled sources would have to use a foam
blanket or poly balls within 6 months and install MACT within
2 years. Also, this commenter felt that facilities that have
installed controls in the absence of a Federal standard should be
allowed 2 years to meet MACT requirements.
.Comment: Two commenters pointed to previous regulatory
actions as reasons why the proposed timeframe of l year for hard
chromium electroplaters is inappropriate. One commenter
(IV-D-23) suggested that sources will need at least 24 months to
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estimate emissions; identify appropriate technology; order,
install, and test equipment; and comply with the General
Provisions and title V. This same commenter pointed out that the
EPA has established 'a 24-month compliance period in the
halogenated solvents NESHAP and does not think that the EPA
adequately explains why a shorter timeframe was proposed for this
rule. Another commenter (IV-D-17) also pointed out that other,
higher priority source categories such as those covered by the
HON have been given 3 years to comply.
Comment: One commenter (IV-D-43) stated that the proposed
timeframe of 1 year for hard chromium electroplaters does not
give States sufficient time to submit requests for equivalency. ^
This same commenter suggested that no notification or compliance
dates should be prior to 1 year after promulgation so that
sources are not confused as to who is the implementing agency
(Federal, State, or local).
Comment: Several commenters stated that the proposed
compliance timeframe of 3 months for decorative chromium
electroplaters and chromium anodizers was insufficient for the
following reasons:
1. Trade associations need time to educate their members
(IV-F-01 [Altmayer, Sonntag], IV-D-19, IV-D-58);
2. Equipment may have to be purchased, the lead time to
purchase equipment is greater than 120 days, and employees must
be trained to use a stalagmometer (IV-F-01 [Altmayer], IV-D-22,
IV-D-58);
3. Facilities will have to research the appropriate
wetting agent, test, and develop a startup/shutdown/malfunction
plan (IV-D-26, IV-D-35, IV-D-59);
4. The compliance timeframe does not consider decorative
chromium platers and chromium anodizers that may have to install,
test, and possibly upgrade add-on controls (IV-F-01 [Altmayer],
.IV-D-09, IV-D-14, IV-D-25, IV-D-40, IV-D-43, IV-D-44, IV-D-47,
IV-D-58, IV-D-59, IV-D-61);
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5. Large sources will have large expenditures for
equipment and personnel to do testing, reporting, and
recordkeeping (IV-D-57);
6. Emissions "from anodizing tanks are low, and there
should therefore be no urgency (IV-D-14);
7. Most of the facilities are area sources and will need
more time to comply (IV-D-42);
8. In the aerospace industry, additional time will be
needed because fume suppressants must be tested to verify that
they do not interfere with other steps or affect the mechanical
and fatigue properties necessary when chromium anodizing is used
as a pretreatment for adhesive bonding, and government
contractors must get government approval prior to changing a
process (IV-D-47, IV-D-52, IV-D-58);
9. The use of fume suppressants would have to be approved
by European customers (IV-D-54); and
10. A 3-month timeframe does not give States time to submit
requests for equivalency (IV-D-43).
Compliance timeframes ranging from 6 months to 3 years were
suggested by commenters (IV-F-01 [Altmayer], IV-D-14, IV-D-19,
IV-D-24, IV-D-22, IV-D-26, IV-D-35, IV-D-40, IV-D-45, IV-D-47,'
IV-D-52, IV-D-54, IV-D-57, IV-D-58, IV-D-59). Two commenters'
(IV-D-58, IV-D-61) suggested that sources that have to install
add-on controls be given the same compliance timeframe as hard
chromium electroplating operations.
Response; The Agency agrees with the commenters that the
compliance timeframes for hard chromium electroplating,
decorative chromium electroplating, and chromium anodizing
sources should be increased. The EPA recognizes that some of the
facilities within all of the source categories will have to
investigate the technical feasibility of installing control
devices at their facility to meet the standards. Also, some
sources performing decorative chromium electroplating and
chromium anodizing will have to investigate the feasibility of
using fume suppressants. Likewise, some hard chromium
electroplating sources that, have control systems that may not
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quite meet the standard may want to investigate using fume
suppressants in conjunction with a control device as a way to
meet the standards. Also, many area sources are not yet aware
•that a rule is to be promulgated for their industry, and the EPA
and various trade associations/industry groups need an
opportunity to notify these facilities of the new requirements.
Based on these and the other reasons provided by the
commenters, the EPA has extended the compliance date to 1 year
after the promulgation date for existing decorative chromium
electroplaters and 2 years after the promulgation date for
existing hard chromium electroplaters and existing chromium
anodizers. The EPA believes that the 1 year timeframe for
decorative chromium electroplaters is sufficient rather than
2 years because, based on EPA's survey of the industry,
80 percent of these sources are already using fume suppressants.
The EPA believes that very few sources will need to install
add-on control devices because fume suppressants are widely
applicable to this source category. In addition, should a source
have to install an add-on air pollution control device, there are
procedures in place for requesting an extension of compliance, if
necessary [§ 63.6(i) and 63.343(a)(6) of subpart A]. A larger
percentage of hard chromium electroplating and chromium anodizing
source categories, on the other hand, will need to evaluate and
implement control techniques to meet the emission limitations.
Therefore, a 2 year compliance timeframe is identified for
existing sources in these source categories. The EPA thinks that
the timeframes in the final rule will address commenters
concerns, and still ensure implementation of controls in a timely
fashion.
Although the Act allows up to 3 years for an existing source
to comply with a standard, the EPA does not think that a 3-year
compliance time is necessary or prudent in this case. A longer
•compliance time has not been allowed due to the toxicity of
-•chromium compounds and the importance of controlling chromium
emissions to protect human health and the environment. Also, the
types of control techniques that are expected to be used to
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comply with the standards are readily available within the 1- or
2-year compliance timeframes.
There may be some special situations in which sources
require additional time to comply with the rule. For example,
government installations covered by this rule have indicated that
they will need extra time to procure funding and to implement
changes. Also, for defense contractors, it is expected that a
new procedure or process (e.g., inclusion of a fume suppressant)
for electroplating or anodizing operations will require
government approval prior to its use. Based on industry
comments, a minimum of 18 months is required to verify a new
process change such as the use of fume suppressants in addition
to the time necessary for implementation.
The EPA recognizes that unique compliance considerations
such as these may exist. Therefore, as previously stated,
§ 63.6 (i) of the General Provisions discusses mechanisms by which
a source can be granted an extension of compliance with the
emission standards. This section allows a source to request a
1-year extension for compliance. In the General Provisions, the
request must be submitted 12 months in advance of the compliance
date identified in the regulation. In § 63.343(a)(6) of the
final rule, the extension must be submitted no later than
6 months before the compliance date for the source. If granted,
this extension combined with the compliance timeframes in the
proposed rule provides a total of 2 years for compliance for
decorative chromium electroplaters and 3 years for compliance for
hard chromium electroplaters and chromium anodizers. This same
section of the General Provisions allows an extension to sources
that have complied with BACT or LAER requirements specifically
related to chromium compounds prior to promulgation of this rule.
Such sources may be granted an extension of the compliance date
for up to 5 years after the date on which such installation was
achieved if the requirements of § 63.6 (i) (2) (ii) of subpart A are
met.
Some commenters, specifically military installations, have
indicated that 5 years would be the minimum timeframe needed for
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them to comply with the rule. The EPA believes that the
extensions described above that are allowed by the General
Provisions may offer some relief. At best, the EPA could extend
the compliance time "up to 3 years which is the maximum allowable.
However, the EPA did not think that the compliance timeframe
should be increased beyond 2 years to accommodate these
facilities due to the toxicity of chromium compounds and the
provisions for obtaining extensions to compliance time under the
General Provisions.
Comment: Four commenters (IV-D-27, IV-D-36, IV-D-47,
IV-D-52) found the proposed rule confusing in its description of
the relationship between the compliance timeframe and the
timeframe for completing a performance test. One commenter
(IV-D-27) found confusing the statement that the compliance
timeframe is 1 year, but that sources have 120 days following
that to conduct a performance test. This commenter had
understood that the test would have to be conducted and
monitoring parameters set within the l year timeframe. Another
commenter (IV-D-36) stated that the General Provisions should
allow testing before the effective date. Two commenters
(IV-D-47, IV-D-52) pointed out that the compliance time specified
in § 63.342(a) presents a dual requirement that sources must
comply within 1 year or at the end of the compliance test,
whichever is shorter. These commenters point out that such a
clause is a disincentive for sources to comply early in the
compliance period, especially if sources have to shut down their
operations if they fail the compliance test. A single compliance
time is suggested.
Response; As previously discussed, the compliance time
specified in the final rule has been changed to 1 year from the
effective date (i.e., promulgation date) for existing decorative
chromium electroplaters and 2 years from the effective date for
existing hard chromium electroplaters and chromium anodizers.
•.The compliance time for new sources is still immediately upon
startup. Since proposal of this rule, the General Provisions to
part 63 have also been promulgated (59 FR 12408).
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Section 63.7(a)(2) requires that source testing be conducted
within 180 days after the compliance date. A source must be in
compliance by the compliance date (e.g., install control
equipment, set up recordkeeping system, etc.) but does not have
to demonstrate compliance through a performance test, nor conduct
compliance monitoring, until 180 days after the compliance date.
This point is clarified in the final rule.
In addition, neither this NESHAP nor the General Provisions
forbid performance testing prior to the effective date of this
standard. Typically, sources wait until promulgation of the rule
to be certain that all changes made from proposal to the final
rule have been accounted for in a facility's compliance efforts.
Some facilities may have a control system in plcice prior to
promulgation, and may also have tested it prior to the
promulgation date to fulfill State permitting requirements. The
EPA recognizes that it would be costly to repeat; a performance
test after promulgation of a Federal rule if a representative
test had recently been conducted. Section 63.344(b) of the final
rule allows a source to use the results of a performance test
conducted by the source at startup to obtain a State operating
permit, as long as the following conditions are met:
1. The test methods and procedures identified in
§ 63.344(c) of the final rule were used during the performance
test;
2. The performance test was conducted under representative
operating conditions for the source;
3. the performance test report contains the elements
required by § 63.344(a); and
• 4. The owner or operator of the affected source for which
the performance test was conducted has sufficient data to
establish the operating parameter values that corresponds to
compliance with the standards, as required for continuous
compliance monitoring under § 63.343(c) of subpart N.
Regarding the dual compliance date, it was not the EPA's
intent to penalize sources that conduct a performance test prior
to the deadlines specified in this rule and in the General
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Provisions. Section 63.342(a) of the final rule has been
clarified; emission limits must not be exceeded on or after the
.compliance date specified in § 63.343(a) for the affected source.
A facility may conduct its performance test at any time prior to
the compliance date, but the facility would not be in violation
due to exceedances until the actual compliance date itself.
Comment: One commenter (IV-D-47) suggested that if a system
fails to meet the standard upon initial testing, the rule should
allow additional time to investigate and correct the problem.
The commenter points to the treatment, storage, and disposal
facilities (TSDF) rule (56 FR 33490, section 265.1081) as an
example.
Response: The final rule allows a 2-year compliance
timeframe, and the General Provisions allow an additional
180 days after the compliance date for a source to demonstrate
compliance through a performance test. If a test is conducted
prior to the compliance deadline and fails, the source can retest
up until the compliance deadline without violating the standard.
The EPA believes that the timeframe for compliance specified in
the final rule is sufficient, and no additional time is necessary
to allow sources to investigate control device problems and
retest.
2.11 SELECTION OF MONITORING REQUIREMENTS
2.11.1 Enhanced Compliance Monitoring for Packed-Bed Scrubber
and Composite Mesh-pad Systems
Comment; There were 11 (IV-D-06, IV-D-10, IV-D-14, IV-D-23,
IV-D-24, IV-D-27, IV-D-36, IV-D-37, IV-D-43, IV-D-47, IV-D-53)
comments on the suitability of measuring gas velocity to
demonstrate ongoing compliance.
One commenter (IV-D-24) stated that, in general, the EPA has
not demonstrated the correlation between the monitoring
parameters and compliance. Four commenters (IV-D-14, IV-D-23,
..IV-D-27, IV-D-36) stated that measurement of both gas velocity
.and pressure drop is redundant because they are proportional; one
of these commenters (IV-D-27) indicated that gas velocity
measurement should not be required because it is a more
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complicated measurement than pressure drop. Three commenters
(IV-D-06, IV-D-10, IV-D-43) stated that, in their opinion, gas
velocity is not related to scrubber performance. According to
one commenter (IV-D-36), only a major malfunction of the scrubber
would cause a change in gas velocity.
One commenter (IV-D-23) suggested daily prejssure drop
measurements be required in lieu of daily gas velocity
measurements. Two commenters (IV-D-47, IV-D-53) suggested
installing an air pressure differential gauge across the scrubber
to monitor air flow, which can be recorded once per day. One of
these commenters (IV-D-53) suggested that the operating permit
should state the maximum and minimum for the velocity or pressure
drop.
Nine commenters (IV-D-06, IV-D-16, IV-D-20, IV-D-28,
IV-D-36, IV-D-37, IV-D-38, IV-D-43, IV-D-53) stated that there
would be difficulties in implementing the gas velocity monitoring
requirements. Two commenters (IV-D-06, IV-D-16) stated that the
measurement method for gas velocity is laborious?. Two commenters
(IV-D-16, IV-D-36) pointed out that a source may not be able to
access an area for measurement and a permanent measurement device
may be fouled by chromic acid. One of these commenters (IV-D-16)
stated that it was unreasonable to require testing for all
combinations of tank operation and duct flows that can occur;
testing at maximum amperage and air flow should be sufficient.
This commenter also indicated that air flows at each tank can
change daily due to the addition of makeup air cind seasonal
changes of air pressure. This commenter and one other commenter
(IV-D-53) each suggested that gas velocity should be measured at
the entrance to the control device, not at each tank. One
commenter (IV-D-38) stated that air velocity should be monitored
in the stack after discharge of the fan to .allow the pitot tube
to stay clean, and not be measured prior to the control device.
Two commenters (IV-D-28, IV-D-37) suggested that the rule
clarify how the acceptable gas velocity ranges cire to be
established; development of a protocol is needed. These
commenters also stated that no compliance test can fully examine
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the range of gas velocities and evaluate their impact on control
performance, especially if the system is designed to operate at a
constant velocity (IV-D-37). This same .commenter (IV-D-37)
suggested that velocity measurements can vary based on ambient
conditions, operator error, differences in pitot tubes, etc.;
therefore, the rule should specify an allowable variance from
that measured during the performance test, e.g., ± 5 percent.
Likewise, one commenter (IV-D-49) recommended that,the regulation
specify an acceptable pressure drop variance of ± 33'percent.
Another commenter (IV-D-27) indicated that during performance
testing, the accuracy of the measurement device should be
accounted for when establishing ranges for the monitoring
parameters.
One commenter (IV-D-38) suggested that for facilities that
cannot afford an automatic monitoring and recording system, a
simple alternative should be considered. For example, because
pressure drop is the primary indicator of proper operation, a
facility could measure pressure drop with a photohelic gauge
which contains a set of relays to perform a function, i.e., an
alarm or a system shutdown.' The commenter suggests that an
automatic or manual washdown for composite mesh-pad systems and a
conductivity control system for packed-bed scrubber systems could
be used in conjunction with this.
Six commenters made remarks regarding the measurement of
chromium concentration in the scrubber water. Four commenters
(IV-D-10, IV-D-24, IV-D-36, IV-D-43) stated that there is no
obvious relationship between scrubber water chromium
concentration and scrubber performance. Another commenter
(IV-D-53) said further research is necessary to establish such a
relationship. This commenter suggested that the scrubber water
chromium concentration limitation be determined on a case-by-case
basis and also suggested that in lieu of scrubber water chromium
concentration, the regulation should require a minimum scrubbing
recirculation rate to the packed-bed scrubber. One commenter
(IV-D-47) indicated that it would be more appropriate to monitor
the pH of the scrubber water and to record this information once
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per day. One commenter (IV-D-24) requested that the requirement
for measuring scrubber water chromium concentration be eliminated
because the hydrometer is not accurate and the process parameters
do not change on a daily basis.
Ten commenters (IV-D-06, IV-D-10, IV-D-24, IV-D-27, IV-D-28,
IV-D-38, IV-D-43, IV-D-44) provided comments on the difficulty of
measuring the chromium concentration in the scrubber water.
Three commenters (iv-D-06, IV-D-24, IV-D-27) indicated that
measurement of the chromium concentration in the scrubber water
with a hydrometer is not accurate. Three commenters (IV-D-10,
IV-D-28, IV-D-43) requested that the rule identify a simpler
measurement method. One commenter (IV-D-44) indicated that use
of a hydrometer to measure scrubber water concentration is
impractical when the scrubber is also used for control of
phosphoric acid or pickling baths. Another commenter (IV-D-38)
suggested that a conductivity control system should be identified
as an alternate method of measurement.
Two commenters (IV-D-10, IV-D-43) stated that small, hard
chromium electroplaters should be exempt from the scrubber water
chromium concentration measurement requirement unless these
requirements are made more flexible; one of these commenters
(IV-D-10) suggested a threshold level of less than
60,000,000 amp-hr/yr. One commenter (IV-D-45) indicated that a
default compliant scrubber water chromium concentration should
not be specified and that sources should set their own value.
Response: The proposed rule included compliance monitoring
provisions in § 63.343(b) and (c). The intent of compliance
monitoring is to monitor a process parameter that is directly
linked to control device performance. In the proposed rule,
sources using a composite mesh-pad system to comply with the
emission limits would monitor gas velocity to determine
compliance with these limits. For sources using a packed-bed
scrubber, it was proposed that gas velocity and concentration of
chromium in the scrubber water be monitored to determine
compliance with the emission limits. The proposed rule also
contained operation and maintenance (O&M) provisions in
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§ 63.345(b) and (c) that were not intended to determine
compliance with the emission limits, but to ensure that the
control device was properly maintained. The EPA added the O&M
provisions because poor maintenance could result in system
degradation over time, and eventually, system breakdown that
would not be immediately obvious through compliance monitoring.
The final rule continues to require compliance monitoring
[§ 63.343(c)], but the O&M provisions have been replaced with
work practice standards [§ 63.342 (f)], which address O&M
practices. Requirements for the compliance monitoring and the
work practice standards are summarized in Table 2-2. As
indicated in Table 2-2, there have been changes to these
requirements from proposal. Changes have been made to address
commenters' concerns while still providing the EPA with the
ability to determine the compliance of a source at any time. The
parameters identified for compliance monitoring have changed
based on the EPA's review of comments received on the proposed
rule and further investigation of which process parameters relate
best to proper performance of the control systems.
For sources complying with the emission limits for hard
chromium electroplating, decorative chromium electroplating, or
chromium anodizing by using a composite mesh-pad system, the
final rule requires that the pressure drop across the control
system be monitored daily to determine compliance with the
emission limits. During the initial performance test, sources
using composite mesh-pad systems will determine the outlet
chromium concentration, and will also determine the average value
of pressure drop across the device that corresponds to a
compliant emission limit. Subsequent operation outside of
± 1 inch of H20 of this pressure drop range constitutes
noncompliance with the emission limits. In lieu of accepting
this default compliant range, owners or operators may conduct
multiple performance tests to establish a range of compliant
pressure drop values.
in developing the proposed rule, the EPA chose gas velocity
as the process parameter^to monitor for compliance when a
2-87
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composite mesh-pad system was used because the control system is
designed to operate within a specific gas velocity range.
.Operation of the control system outside of this velocity range
can lead to performance problems. In revising the proposed rule,
the EPA recognizes that the measurement of gas velocity could be
burdensome and that other control system parameters' could
potentially be used to determine ongoing compliance. In the
final rule, sources using composite mesh-pad systems are required
to monitor pressure drop across the device for compliance
purposes. Based on information gathered by the EPA, the pressure
drop is directly related to composite mesh-pad system
performance. Also, based on comments received, measurement of
pressure drop is straightforward, and is, in,fact, currently
being monitored by some users of composite mesh-pad systems. The
EPA believes that this change makes the rule more flexible for
regulated sources, while still ensuring that the EPA has a
mechanism for determining compliance with the emission limits at
any given time.
The compliance monitoring for packed-bed scrubbers in the
final rule is slightly different than that for composite mesh-pad
systems. As indicated in Table 2-2, a source using a paeked-bed
scrubber to meet an emission limit must measure the velocity
pressure at the inlet to the control system as well as the
pressure drop across the device. The relationship between
pressure drop and packed-bed scrubber performance is less
reliable than the relationship between pressure drop and
composite mesh-pad system performance because of the lower
pressure drop in packed-bed scrubbers. Therefore, the EPA
requires sources using packed-bed scrubbers to also monitor the
velocity pressure at the inlet to the control device. This
requirement will ensure that the gas velocity through the control
system is being maintained in accordance with vendor
recommendations and, along with the pressure drop monitoring,
will ensure that the source is in compliance with the standard.
The requirement that sources using packed-bed scrubbers
monitor the chromium concentration in the scrubber water has been
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eliminated. Upon further review of the proposed monitoring
requirements, the EPA concluded that monitoring of the velocity
pressure at the control device inlet and the pressure drop across
the device was sufficient to demonstrate compliance with the
emission limits when packed-bed scrubbers are used. It is
unlikely that the chromium concentration in the scrubber water
would increase to the level identified in the proposed rule
(45 g/L [6 oz/gal]) because of the industry practice to recycle
the scrubber water as plating bath make-up water. Also, most
sources using packed-bed scrubbers will be small sources; in
revising the regulation, the EPA worked towards reducing the
burden on small sources wherever feasible.
Compliance monitoring requirements for fiber-bed mist
eliminators have been added in the final rule. For sources
complying with the emission limits for hard chromium
electroplating, decorative chromium electroplating, or chromium
anodizing by using a fiber-bed mist eliminator, the rule requires
that the pressure drop across both the fiber-bed mist-eliminator
and the upstream control system used to prevent plugging be
monitored daily to determine compliance with the emission limits.
During the initial performance test, sources using fiber-bed mist
eliminators will determine the outlet chromium concentration, and
will also determine the average value of pressure drop across the
fiber-bed mist eliminator and upstream control device that
corresponds to a compliant emission limit. Subsequent operation
outside of ± 1 inch of water column of this pressure drop range
constitutes noncompliance with the emission limits. In lieu of
accepting this default compliant range, owners or operators may
conduct multiple performance tests to establish a range of
compliant pressure drop values.
Manycommenters requested guidance on how to measure the
process parameters to determine compliance. The final rule
includes a method that sources must use for establishing the
velocity pressure. The rule also contains procedures for
establishing the pressure drop across the unit that sources may
use if they wish. The methods identified are straightforward and
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can be performed at a low cost to the plants. For example, the
velocity pressure at the inlet to the control device can be
monitored by permanently mounting a plastic type-S pitot tube
.•that is connected to" a magnahelic gauge that records the velocity
pressure. To measure the pressure drop, pressure taps can be
located on both sides of the packed bed, mesh pads, or fiber
beds, as appropriate. Tubing connected to these two taps can
then be sent to another magnahelic gauge. The EPA has installed
such a system and has found that corrosion problems associated
with chromic acid are alleviated by using a plastic pitot tube
and plastic pressure taps instead of metal. Once the monitoring
devices are installed, the only labor required is the recording^
of the magnahelic readings. Alternately, a strip chart recorder
could be used with the gauges, and high/low alarms used to
..indicate when values were close to exceeding the compliant
ranges. Once the pitot tube is in place, the magnahelic gauge
connected to the pitot tube can then be "zeroed." The magnahelic
gauge would then be monitored once a day to ensure no change in
the velocity pressure has occurred. The final rule (Table 2)
also specifies work practice standards for pitot tubes.
One requirement that is consistent between the proposed and
final rules is the requirement that sources set the values for
the operating parameters to be monitored for compliance. The EPA
does not think it is appropriate to identify the actual values
for the compliant operating parameters in the rule. Each control
device is different depending on the manufacturer, the age, the
type of process operation being controlled, maintenance
procedures, etc. The EPA does believe, however, that it is
reasonable to specify an allowable variance because it would be
very difficult for an owner or operator to establish a variance
during one, three-run performance test. In the final rule, an
.owner or operator is out of compliance with the standard if the
-pressure drop varies by ± 1 inch of water column from the average
^operating parameter value established during the initial
performance test. Likewise, an owner or operator is out of
compliance with the standard if the velocity pressure varies by
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± 10 percent from the average operating parameter value
established during the initial performance test. In lieu of
accepting these default compliant ranges, an owner or operator
can set the compliant range of operating parameter values by
conducting multiple performance tests.
Comment: Two commenters (IV-D-20, IV-D-43) suggested that
§ 63.343(b), which requires determination of outlet chromium
concentration in an initial performance test and monitoring of
gas velocity and scrubber concentration, should apply to all
tanks, not just hard chromium electroplating tanks. Otherwise,
sections 63.345(b) and (c), which refer to maintenance practices
for composite mesh-pad and packed-bed scrubber systems,
respectively, are not enforceable.
Response: The rule has been revised to clarify that
monitoring requirements are based on the type of control
technique used, not on the type of tank operated. Therefore, the
same monitoring applies regardless of whether the control device
is being used to control chromium emissions from a hard chromium
electroplating tank, decorative chromium electroplating tank, or
a chromium anodizing tank.
Comment; One commenter (IV-D-20) noted that the preamble
states that pressure drop measurement will be used as an
indication of noncompliance but will not be a noncompliance
trigger; this exclusion is not evident in the rule.
Response; As stated above, the compliance monitoring
requirements have been revised so that pressure drop monitoring
is required in lieu of gas velocity monitoring. Table 2 in the
final rule specifies work practice standards, and § 63.343(c)
specifies monitoring requirements to determine continuous
compliance with the emission limits.
2 •1:L'2 Selection of Proposed Operation and Maintenanr.A
Requirements for Packed-Bed Scrubber and Composite Mesh-
Pad Systems
2.11.2.1 Maintenance Requirements for Packed-Bed Scrubbers.
One commenter (IV-D-59) indicated that wastewater requirements
for packed-bed type washers are unreasonable, but did not
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elaborate on the specific "wastewater requirements" to which he
was referring. Three commenters (IV-D-14, IV-D-37, IV-D-38)
suggested the EPA revise the requirement for adding makeup water
'at the top of the scrubber because makeup is typically added to
the scrubber basin or at the front of the scrubber. One of these
commenters (IV-D-37) stated that some scrubber systems are
vertical and some are horizontal and suggested that the term top
be further clarified; this commenter questioned whether the term
top refers to the upstream or downstream side. Another commenter
(IV-D-24) indicated that the location for addition of make-up
water should not be specified in the rule. One commenter
(IV-D-58) noted that several scrubber manufacturers have
indicated that the requirement to supply fresh makeup water at
the top of the scrubber unit is either impossible or not
recommended for their equipment.
Three commenters (IV-D-21, IV-D-37, IV-D-51) questioned
whether washdown water for the composite mesh pads and makeup
water additions for scrubbers can be done with electroplating
rinse instead of fresh water. One of these commenters (IV-D-21)
pointed out that wastewater would be increased by using fresh
water. This commenter also questioned whether shutdown of the
control system is desirable because OSHA regulations may be
exceeded during this time. Another of these commenters (IV-D-37)
stated that use of fresh water deters pollution prevention
practices; according to another (IV-D-51), the concentration of
chromium in the rinse water will be much less than that on the
pad and should therefore be acceptable. This commenter also
stated that for composite mesh-pad systems that contain three
pads, the fluid from the second stage is recirculated and used to
clean the front pad; the concentration of this recirculated fluid
is usually below 100 mg/L.
One commenter (IV-D-29) requested that section 63.345(b)(3)
and (c)(3) be revised to state, "When makeup additions occur,
Censure that all makeup water is fresh or lower in total dissolved
solids (TDS) (2,000 ppm or less) and total chromium (400 ppm or
less) and supplied either to the top of the packed bed or its
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reservoir." One commenter (IV-D-37) asked that the term fresh
water be defined in the rule.
Response: Section 63.345(c)(3) of the proposed rule
erroneously required" that sources using composite mesh-pad
systems ensure that all makeup water is fresh and supplied to the
unit at the top of the packed bed whenever makeup additions
occur. This requirement was intended for packed-bed scrubbers
only and has been corrected in the final rule.
In light of comments received on the proposed O&M monitoring
requirements, the EPA has included the O&M requirements as work
practice standards in § 63.342(f) the final rule, and has reduced
the burden to the extent possible while still ensuring that units
will be properly maintained. In the final rule,, the inspections
to ensure proper drainage, no chromic acid buildup, and no
chemical attack on the structural integrity, and the inspection
of the chevron-blade mist eliminator remains, but the frequency
of inspections has been reduced from daily or monthly to .
quarterly. An additional quarterly inspection has been added,
however; owners or operators must inspect ductwork from the
affected source (s) to the control device to ensiire that there are
no leaks. These requirements apply to all add-on air pollution
control devices.
The final rule continues to require sources using packed-bed
scrubbers to meet an emission limitation ensure that all makeup
water is fresh and supplied to the unit at the top of the packed
bed whenever makeup additions occur. The EPA considers this
requirement essential to meeting the prescribed emission limit.
During source testing conducted by the EPA to esstablish the
performance level of packed-bed scrubbers, it was noted that a
system equipped with an overhead spray system that periodically
cleaned the packing with fresh water performed much better than a
system without such cleaning. Therefore, the EPA conducted a
test to determine the affect of periodic and continuous washdown
of the packed bed on system performance. In this test, emissions
were measured when no overhead washdown occurred, when periodic
washdown occurred, and when continuous washdown occurred. Clean
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water was used in the washdowns. The tests showed that the
emissions from the scrubber were reduced when periodic washdown
..occurred, yet continuous washdown did not offer substantial
additional benefit over periodic washdown. (Test results are
described in detail in Chapter 4 of the Proposal BID.)
Packed-bed scrubber systems that did not incorporate this
washdown technique could not meet the emission limit in the rule.
Based on the above results, the EPA decided that the rule
should require periodic washdown of packed-bed scrubbers with
fresh water whenever makeup additions occur because such systems
offer additional environmental benefit. (The final rule defines
fresh water.) Makeup water is added to replace water that has
been evaporated in the scrubber system, to replace scrubber water
recycled to the plating tanks, or to replace water discharged to
the wastewater treatment system. Therefore, there is no increase
in the wastewater burden on the facility. Water from the
scrubber will continue to be recycled to the electroplating bath
to make up for electroplating bath evaporative losses. The only
difference is that the water that would then be added to the
scrubber as makeup must be fresh and added to the top. If
electroplating rinse water meets the definition of fresh provided
in the final rule, it can be used.
To further clarify the makeup water requirement, top has
been defined in the rule for horizontal-flow scrubbers as the
section of the unit directly above the packing media such that
the makeup water would flow perpendicular to the air flow through
the packing. For vertical-flow units, the top would refer to the
area downstream of the packing material such that the makeup
water would flow countercurrent to the air flow through the unit.
The EPA believes that if the requirement that makeup water be
fresh and added to the top of the packed bed is not included,
scrubbers will not continuously meet the required emission limit,
even if the scrubber met the limit during the initial performance
test and the pressure drop and velocity pressure measurements are
within the appropriate ranges. Therefore, the washdown
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requirement was added as a work practice standard that serves as
another means of ensuring compliance with the standard.
Based on comments received, there seems to be some confusion
related to implementing this periodic washdown with fresh water.
Contrary to commenters concerns, the scrubber system does not
have to be turned off in order to wash down the packed bed.
Also, the EPA does not think that substantial retrofit would be
required to incorporate periodic washdown of the packed bed.
During the source test to determine the effect of periodic
washdown, the EPA retrofitted an existing scrubber using readily
available equipment at minimal cost.
2.11.2.2 Maintenance Requirements for Composite Mesh-Pad
Systems.
Comment: Eleven commenters (IV-F-01 [Schott, Kimre],
IV-D-16, IV-D-17, IV-D-23, IV-D-24, IV-D-37, IV-D-38, IV-D-49,
IV-D-51, IV-D-58) provided comments on the washdown requirements
for composite mesh-pad systems.
Three commenters (IV-D-38, IV-D-51, IV-D-58) indicated that
a 10-minute wash is not appropriate for every unit. Two of these
commenters (IV-D-38, IV-D-58) also noted that although the rule
requires shutdown of the fan for washdown, some units are cleaned
better with the exhaust fan on. One cornmenter (IV-D-51) noted
that tests performed on one composite mesh-pad unit indicate that
there is no further benefit to washdown after 1 1/2 minutes.
Pour commenters (IV-D-16, IV-D-17, IV-D-37, IV-D-58) said daily
washdown is not feasible if electroplating time exceeds 24 hours.
Another commenter (IV-D-17) indicated that if multiple tanks are
connected to a control device, it is likely that at least one
will always be operating, and shutting down the control system
for washdown would ruin work in progress. This commenter
recommended deleting the washdown requirements. Seven commenters
(IV-F-01 [Schott, Kimre], IV-D-23, IV-D-24, IV-D-37, IV-D-38,
IV-D-58) suggested washdown requirements for composite mesh-pad
systems be site-specific, as recommended by vendors, or only if
pressure drop determinations indicate the potential presence of '
chromic acid buildup (IV-D-23).
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Two commenters (IV-D-16, IV-D-37) indicated that some
composite mesh-pad systems have automatic daily washdown and
•suggested that such systems be excluded.from the requirements.
Another commenter (IV-D-38) recommended that daily recordkeeping
of washdown times and durations not be required if the source
demonstrates that a well-designed and functioning automatic
washdown control panel is being used. One commenter (IV-D-24)
stated that systems with automatic washdown are difficult to
inspect on a monthly basis. Another commenter (IV-D-49) noted
that, regarding the monthly inspection, chromic acid should never
be present in the back portion of the pad but moisture will be
present when washdown occurs from the back of the pad.
Two commenters (IV-D-23, IV-D-51) suggested that the
washdown water will likely exceed the quantity of water that can
be recycled, thus resulting in a wastewater stream that needs to
be treated. One of these commenters (IV-D-51) stated that the
volume of fluid from washdown and reclaimed rinse waters cannot
exceed the volume of water evaporated by the electroplating tank
(in an attempt to eliminate wastewater). This commenter also
noted it is desirable to use rinsewater as makeup water in the
electroplating tank because fresh water can then be added to the
rinse tank, thus reducing chromium concentration and exposure.
In addition to the requirement for daily spray cleaning of
composite mesh-pad systems, commenter IV-D-51 stated that the
first mesh pad should be immersed in a rinse tank at a frequency
of once per week to once per month, depending on the system.
According to this commenter, mesh pads should always be removable
to facilitate immersion cleaning and to facilitate visual
inspection and repair or replacement.
Response; In the final rule, the EPA has revised the
requirement that sources complying with an emission limit by
using a composite mesh-pad system perform washdown of the pads on
,a daily basis. Instead, the final rule requires that washdown of
^the pads in a composite mesh-pad system occur in accordance with
manufacturer's recommendations as part of a facility's O&M plan
required by the work practice standards [§ 63.342 (f)] . The EPA
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believes that washdown is an essential part of composite mesh-pad
system operation; if proper system maintenance such as washdown
does not occur, there will be a decline in system performance.
The EPA recognizes that vendor designs for these systems vary
significantly and the requirements for washdown are based on the
design of the unit and the operation of the plating tanks.
Therefore, a specific washdown frequency is not included in the
final rule. The frequency of washdown is dependent upon the
position of the pad in the control unit. Pads located in the
front portions of the unit are exposed to higher chromium
concentrations and, therefore, require washdowns more frequently
than those in the back of the unit. Washdown practices
recommended by manufacturers vary from continuous in some cases *
to a maximum of once every one to two weeks. Also, as noted in
the previous response, the monthly inspections of the composite
mesh-pad systems have been changed to quarterly inspections.
As previously stated, in the final rule monitoring and work
practice requirements for fiber-bed mist eliminators have also
been added. A washdown requirement, similar to that for
composite mesh-pad systems,"is included for fiber-bed units.
Fiber-bed units installed downstream of more efficient
prefiltering systems, such as packed-bed scrubbers, will require
less frequent washdown than those using a less effective
prefiltering device because of the lower inlet loading to the
unit. Most vendors of fiber-bed units recommend monitoring of
the pressure drop as a means of gauging when the unit needs to be
washed down. If an increase in pressure drop is observed, then
the unit will be washed down to remove any chromium built up on
the fiber elements.
2 ' -11 *2 '3 Operation and Maintenance Requirements- -General
Comment; Eight commenters (IV-D-01, IV-D-03, IV-D-09,
IV-D-17, IV-D-24, IV-D-45, IV-D-47, IV-D-49) provided comments on
the appropriateness of O&M requirements in general. Two
commenters (IV-D-01, IV-D-03) suggested that the O&M plan
requirements be made more general to make them applicable to
sources complying with either a control device, a fume
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suppressant, or both. One commenter (IV-0-09) questioned whether
the EPA has justification for setting standards for O&M
requirements of scrubbers used at decorative chromium facilities
because none of the decorative chromium facilities tested use
scrubbers.
One commenter (IV-D-47) stated the maintenance practices are
burdensome and would require reconfiguration of most systems.
This commenter also suggested that only vendor-recommended
operating parameters should be monitored on a routine basis. In
addition to these comments, this commenter also suggested that
more appropriate monitoring could include the following
measurements that would be recorded once each day: (1) airflow,^
(2) recirculating spray water and make-up water flow rates, and
(3) pH of scrubber water.
One commenter (IV-D-17) indicated that requiring a source to
notify supervisory personnel immediately upon identifying a
malfunction is unnecessary because the General Provisions require
sources to affect a repair of a malfunction as soon as is
practicable. Another commenter (IV-D-45) requested that, in
addition to the maintenance practices specified, the rule also
specify procedures to follow if something is found to be wrong.
Response: The final rule has more detailed requirements for
the O&M plan required by the work practice standards, some of
which refer to all sources regardless of control technique, and
others that are control technique-specific. The requirements for
the O&M plan in the final rule have been made more detailed than
the requirements in the proposed rule, because these requirements
-are overriding § 63.6(e)(3) of the General Provisions. This
section of the General Provisions requires a startup, shutdown,
malfunction plan, which in many respects is not applicable to
this source category. Therefore, the O&M plan incorporates those
parts that are applicable, and has some additional requirements
..specific to this source category. The requirements of the O&M
plan are outlined in § 63.342(f) (3) of the final rule.
The EPA disagrees that the work practice standards are
burdensome and will require substantial reconfiguration of
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control systems. The final rule has reduced the frequency of
maintenance inspections and has revised some of the other work
practice standards to make them less burdensome. As stated
above, the EPA believes that the retrofit that will be required
to incorporate work practice standards can be accomplished at
minimal cost to the facility. The EPA also believes that the
work practice standards specified for the various control devices
are justified, even if the devices evaluated and tested by the
EPA were not used to control decorative chromium electroplating
baths. Proper maintenance of the control devices that are likely
to be used by this source category is not dependent on the type
of electroplating or anodizing bath being controlled.
Cpmment; One commenter (IV-D-24) suggested several changes
to § 63.345(a) (1)- (3), including use of the term velocity
pressure traverse in place of velocity traverse and use of static
pressure in place of velocity pressure. Other changes that this
commenter suggested for the gas velocity measurement include
(1) addition of instructions for ducts with larger diameters;
(2) addition of barometric pressure and duct temperature
measurements; (3) removal of the temperature requirement of 70°F
because tank temperature would have to be decreased, and the
measurement would not reflect actual operating conditions; and
(4) use of the term velocity points in place of velocity pressure
readings and use of the term traverse test point to obtain the
traverse point of average velocity pressure. Another commenter
(IV-D-28)recommended deleting the requirement that stack
temperature must be approximately 70 °F during initial performance
testing of the velocity traverse because this temperature cannot
be controlled or adjusted. One commenter (IV-D-37) asked that
alternate velocity measurements be allowed, such as the use of
manometers that measure static pressure to indicate changes in
ventilation. Another commenter (IV-D-38) suggested that use of
an air velocity magnahelic gauge is appropriate. This commenter
also suggested that pressure drop could be measured using a
pressure differential magnahelic gauge located inside the
building at a convenient area for visual monitoring.
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Response; As discussed previously, gas velocity is no
longer considered as a continuous monitoring requirement for
control systems. However, the final rule does require that the
velocity pressure at the inlet to the control system be measured
once per day to ensure compliance with the emission limit for
users of packed-bed scrubbers. The comments above are based on
the need to do a velocity traverse every day and to calculate
velocities; this is not required in the final rule. In addition,
the stack temperature specification of 70°F was selected because
the gas temperature would reach that temperature value at some
time of the day every day of the year. However, the final rule
does not contain this temperature requirement.
Comment: Two commenters (IV-D-17, IV-D-28) requested that
the preparation of the O&M plan be linked to the compliance date.
As the rule currently reads, the O&M plan must be implemented
within 90 days of the effective date while hard chromium sources
have 1 year in which to comply; this suggests that sources may
have to develop a plan for a control device prior to its being
installed.
Response; The final rule has been clarified so that
implementation of the O&M plan is tied to the compliance date,
not the effective date, of the standards.
2.11.3 Frequency of Monitoring
Comment; Fourteen commenters indicated that the required
frequency of monitoring is inappropriate. One commenter
(IV-D-59) explained that daily monitoring of gas velocity is
unreasonable because it takes considerable time, equipment, and
training. Two other commenters (IV-D-14, IV-D-61) said the rule
should state that daily monitoring is only required when the tank
is in operation. One commenter (IV-D-36) suggested velocity
measurements be done quarterly because pressure drop would be
measured daily. Another commenter (IV-D-06) suggested that the
.ventilation systems should be checked annually as is consistent
with CAL/OSHA.
Two commenters (IV-D-06, IV-D-36) stated that the
monitoring, recordkeeping, and reporting requirements are
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excessive and daily monitoring is not necessary for nonvariable
control systems such as packed-bed scrubbers and composite mesh-
pad systems; one of these commenters (iv-D-36) stated that, in
general, quarterly monitoring is sufficient. Another commenter
(IV-D-28) indicated that weekly monitoring would be sufficient.
Another commenter (IV-D-09) agreed, stating that daily monitoring
of steady state control systems is too frequent.
One commenter (IV-D-14) suggested that the maintenance
schedule for the control equipment should be consistent with the
manufacturer's recommendations; for example, some manufacturers
recommend monthly pressure drop readings. This commenter also
recommended that monitoring should be part of normal preventive
maintenance that occurs annually, monthly, or weekly depending on
the parameter. One commenter (IV-D-16) stated that the
monitoring requirements in the rule would require a full time
position to measure and record air flow information. One
commenter (IV-D-57) indicated that daily monitoring is excessive
for small sources and suggested that this requirement be reduced
if the source can show that compliance can be maintained with
less frequent monitoring.
One commenter (IV-D-10) suggested monitoring be tied to
production rate or throughput (amp-hr/yr). Three commenters
(IV-D-23, IV-D-24, IV-D-28) suggested monitoring should only be
conducted on the days when electroplating operations are taking
place, and one of these commenters (IV-D-24) requested that the
tank be considered in operation only when the current is actually
applied to the bath. One commenter (IV-D-14) suggested
monitoring frequency be established through the O&M plan, which
is reviewed by the local air district. One commenter (IV-D-44)
indicated that monitoring frequency should be reduced after
compliance has been demonstrated for 6 months as is allowed in
40 CFR part 61 subpart V, and another commenter (IV-D-27)
suggested this reduction in monitoring frequency specifically for
monitoring of the scrubber water concentration.
.Comment: Six commenters indicated that the required
frequency of monitoring chromium concentration in the scrubber
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water is inappropriate. One commenter .(IV-D-09) noted that for
scrubber systems, NPDES only requires weekly monitoring of
..wastewater discharge. Another commenter (IV-D-27) also suggested
that the specified frequency for measuring scrubber water
concentration should be weekly. This commenter indicated that
daily monitoring of scrubber water is excessive and expensive,
costing $200 per day per scrubber unit. One commenter (IV-D-37)
pointed out that it would take most scrubber systems a very long
time to reach a level of 45 g/L, and therefore, daily monitoring
is overly conservative. This commenter also suggested that
monitoring occur monthly or before any complete turnover of
scrubber water volume, whichever is earlier. One commenter
(IV-D-36) stated that daily measurement of scrubber water
concentration is not necessary if a system is automated such that
waters with a chromium concentration greater than that specified
in the proposed rule are not discharged. Another commenter
(IV-D-14) suggested that daily measurement of scrubber water
concentration is inappropriate for a continuous discharge system
and should only be required for batch discharge. Another
commenter (IV-D-17) stated that daily measurement is not
necessary for systems that only have one pass of water through
the scrubber because the chromium concentration would not be near
the concentration limit.
Comment: One commenter (IV-F-01 [Sonntag]) stated that the
paperwork, testing, and sampling burden is excessive, especially
the OSM plan and the 10-minute washdown requirement for the
composite mesh-pad system. One commenter (IV-D-61) suggested the
rule clarify that daily washdown needs to occur only when the
tanks are operating. One commenter (IV-D-24) indicated that
measuring pressure drop daily is excessive and should be measured
only weekly. Another commenter (IV-D-57) stated that daily
monitoring is excessive for small sources and should be reduced
,if a source can show that compliance can be maintained with less
..frequent monitoring. Two commenters (IV-D-17, IV-D-58) suggested
O&M requirements should be consistent with the manufacturer's
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recommendations and should not require hourly or daily
inspections, measurements, or recordkeeping.
Comment: One commenter (IV-D-58) suggested inspections
should only occur if other factors indicate the equipment is
malfunctioning. Two commenters (IV-D-17, IV-D-58) asked that
inspection of packed-bed scrubber, chevron-blade mist eliminator,
and composite mesh-pad systems be changed to semiannual and
pointed out that daily monitoring results in increased exposure
hazards to persons conducting the inspections. Three commenters
(IV-D-24, IV-D-47, IV-D-49) pointed out that some control systems
(i.e., packed-bed scrubber systems) are inaccessible and that
inspections will result in down-time; therefore, the inspection
frequency should be an annual requirement or should be dropped.
One of these commenters (IV-D-24) explained that baffle-type
chevron-blade mist eliminators would have to be removed
(down-time is 2 to 3 days) and suggested that this requirement be
eliminated. Another (IV-D-49) stated that visual inspection of
the pad, which is required by §63.345(c)(2), should occur on a
monthly, not a daily, basis.
Response; As stated above, the compliance monitoring and
work practice standards (which were O&M requirements in the
proposed rule) have been reduced to minimize the burden on
regulated sources. The final rule continues to require daily
monitoring of pressure drop and velocity pressure for compliance,
but the monitoring procedures specified in the rule are minimal.
Once the monitoring devices are in place, the labor required is
only that needed to read the gauges. Compliance monitoring for
sources using packed-bed scrubbers has been reduced in that these
sources are not required by the final rule to measure the
chromium concentration in the scrubber water (see discussion in
Section 2.11.1).
The frequency of inspections associated with the work
practice standards has also been reduced or revised. The
proposed rule required that inspection of the control device for
drainage, chromic acid buildup and system integrity occur once
per month. Also, the back portion of the mesh pads (for
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composite mesh-pad systems) or the chevron-blade mist eliminator
(for packed-bed scrubbers) was to occur once per day. These
requirements remain in the final rule, but the frequency of both
has been reduced to "once per quarter (every 3 months). (A
similar inspection has also been added for users of fiber-bed
mist eliminators.) The EPA believes that the inspections are
still necessary to ensure that system degradation is not
occurring over time, because gradual degradation may not be
indicated by the compliance monitoring. The EPA also believes
that the reduction in frequency will minimize the burden on
affected sources. Some commenters noted that their systems were
not accessible for inspection, or that the inspection would
result in extended downtime. The compliance timeframe in the
final rule should allow sources sufficient time to retrofit their
systems, if necessary, so that inspections can occur. The
negative effects of any downtime are minimized by inspection
frequency being reduced to once per quarter.
Other aspects of the work practice standards have been
revised. For example, daily washdown of composite mesh pads is
no longer required; instead, manufacturers recommendations are to
be followed. In the proposed rule, pressure drop measurement was
specified as an O&M monitoring requirement in addition to the
compliance monitoring. In the final rule, pressure drop is
required for compliance monitoring purposes only.
Several commenters noted that in terms of monitoring and
compliance with the emission limit, the proposed rule was unclear
as to whether a facility must comply with the rule at all times
or only when the tank is operated. The final rule has been
clarified so that requirements apply only during tank operation.
Further, tank operation has been defined as any time that current
and/or voltage is being applied to a chromium electroplating or
chromium anodizing tank or any one affected tank in a series of
chromium electroplating or anodizing tanks ventilated to a common
control system. .
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2-11-4 Alternate Compliance Monitoring for sources Using
Suppressants
2.11.4.1 Appropriateness of Surface Tension Value for Tvr
Baths. •"
Comment: Five commenters suggested that the requirement for
maintaining surface tension below 55 dynes/cm for trivalent
chromium baths is inappropriate. One commenter (IV-D-59)
indicated that the surface tension limits should, be eliminated.
This commenter and one other (IV-F-01 [Altmayer]) pointed out
that, typically, surface tension is approximately 40 dynes/cm.
These commenters indicated that the electroplating process would
not operate properly unless the surface tension was maintained
properly, and therefore the surface tension should not be
regulated. One commenter (IV-F-01 [Sonntag]} questioned why
surface tension is regulated if it is an inherent bath property.
One commenter (IV-D-22) stated that a 55 dynes/cm limit may not
be practical for optimum operation; this commenter indicated that
the EPA data in this regard may be coincidental and adequate
research has not been done to demonstrate that all commercially
available TVC processes operate best at this surface tension.
Two other commenters (IV-D-22, IV-D-26) also noted that surface
tensions above 40 dynes/cm result in unacceptable electroplating
quality. These commenters stated that monitoring the surface
tension every 4 hours to show that it remains below 55 dynes/cm
is unnecessary.
Response: AS discussed in Section 2.6.1, the regulatory
burden on owners or operators of decorative chromium
electroplating tanks that use a trivalent chromium electroplating
process has been greatly reduced if the trivalent bath
incorporates a wetting agent. There are no monitoring
requirements associated with such baths in the final rule. For
those trivalent chromium processes that do not incorporate a
wetting agent as part of the process, the requirements for
decorative chromium electroplaters using a chromic acid bath
apply. That is, monitoring of the bath surface tension is
necessary to maintain a level of 45 dynes/cm, or monitoring must
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be conducted to demonstrate an emission control limit of
0.01 mg/dscm if an add-on air pollution control device is used.
2.11.4.2 Appropriateness of Surface Tension for Chromic
Acid Baths.
Comment: Seven commenters (IV-D-09, IV-D-10, IV-D-24,
IV-D-43, IV-D-45, IV-D-47, IV-D-52) indicated that the
requirement for maintaining surface tension below 40 dynes/cm for
chromic acid baths is inappropriate. Two commenters (IV-D-10,
IV-D-43) indicated that a surface tension standard may not be
prudent to demonstrate compliance. One commenter (IV-D-24)
stated that a direct correlation between exceedance of parameters
and the emission limit has not been established. One commenter
(IV-D-45) suggested that a default compliant surface tension
should not be specified by the rule and that sources should set
their own compliance value.
Two commenters (IV-D-09, IV-G-01) stated that the
40 dynes/cm limit is too low. Two other commenters (IV-D-47,
IV-D-52) stated that vendors recommend a 40-45 dynes/cm range and
that the rule should state that the surface tension be consistent
with manufacturers' recommendations.
Response: There are two types of fume suppressants that are
expected to be used to comply with the final rule: wetting
agents and foam blankets. Sources can use one or the other of
these to inhibit chromic acid emissions, or may use them in
combination. Wetting agents inhibit misting by lowering the
surface tension of the electroplating or anodizing bath; thus,
there is a direct relationship between surface tension and
wetting agent performance. Foam blankets, on the other hand,
limit.mists by trapping the mist under a layer of foam; the
surface tension is not reduced. Section 63.342(b)(2) of the
proposed rule allowed decorative chromium electroplating sources
.using fume suppressants to comply with the standard to meet a
.surface tension of 40 dynes/cm in lieu of meeting the emission
:i.limit. This section should have allowed the surface tension
limit only for those sources using wetting agents, or a
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combination wetting agent/foam blanket. The final rule is clear
in this requirement.
The EPA believes that it is necessary and appropriate to set
a default value for surface tension in the rule. Based on the
EPA's experience, many decorative chromium electroplating tanks
are not ventilated, making source testing impossible without
considerable retrofitting. The EPA had proposed a default
surface tension limit of 40 dynes/cm, but has increased this
value to 45 dynes/cm based on information submitted at proposal
regarding the surface tension ranges recommended by vendors of
wetting agents. However, if a facility believes that a different
surface tension value is appropriate, the rule allows a source to
conduct a performance test concurrently with surface tension
monitoring to establish the maximum surface tension that
corresponds to compliance with the emission limits. The source
would subsequently monitor surface tension, with an exceedance
occurring if the surface tension value of the bath was greater
than that measured during the performance test.
Comment: Two commenters (IV-D-09, IV-D-59) noted that the
rule appears to penalize owners using fume suppressants in
conjunction with a control device in that both the surface
tension and the control device must be monitored. Two commenters
(IV-D-09, IV-G-01) stated that monitoring requirements should be
selected by these sources and should be less frequent than for
those with only one control method. Another corrmenter (IV-D-59)
stated that it is unclear which monitoring method applies if a
source measures surface tension in association with fume
suppressant use and also has an air pollution control device.
Response; The final rule is clear in that the monitoring
requirements of the source are associated with the control
technique that is being used to meet the emission limits or
surface tension limits. For example, a source may be using both
a wetting agent and a packed-bed scrubber on a decorative
chromium electroplating bath. If the wetting agent alone meets
the standards (i.e., lowers the surface tension to below
45 dynes/cm), testing and monitoring of the control device is not
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necessary. If however, a source is using a foam blanket and a
packed-bed scrubber to control emissions from a hard chromium
electroplating tank, and both control techniques are necessary to
meet the prescribed emission limit, the monitoring and testing
associated with both the foam blanket and the scrubber must be
performed.
2.11.4.3 Frequency of Monitoring Surface Tension.
Comment: Twenty-one commenters '(IV-F-01 [Altmayer, Wenske],
IV-D-02, IV-D-05, IV-D-09, IV-D-10, IV-D-17, IV-D-18, IV-D-22,
IV-D-24, IV-D-25, IV-D-26, IV-D-35, IV-D-47, IV-D-48, IV-D-53,
IV-D-57, IV-D-58, IV-D-59, IV-D-61, IV-G-01) provided comments
related'to the frequency of monitoring surface tension. Several
of these commenters made recommendations for more appropriate
monitoring schedules, ranging from daily to monthly monitoring,
in place of the 4-hour schedule.
One commenter (IV-D-02) asked the basis for the 4-hour
monitoring schedule. One commenter (IV-D-18) stated that
monitoring every 4 hours is burdensome and suggested once per
month as an alternative. Two commenters (IV-F-01 [Altmayer],
IV-D-09) indicated that monitoring surface tension every 4 hours
is onerous because it is time-consuming to perform the
measurement. These commenters suggested the frequency be
decreased if a continuous feed system is used or if there has
been compliance over the 4-hour period. Three commenters
(IV-D-24, IV-D-53, IV-D-57) recommended once per operational day
as an appropriate schedule; one of these commenters indicated
that testing requires 45 minutes to complete (IV-D-53) and
another indicated 0.5 to 1.5 hours (IV-D-59) is needed for
testing. One commenter (IV-D-05) stated that calibration and
analysis of one sample with a stalagmometer will take 1.5 to
1.75 hours, and monitoring every 4 hours could conceivably occupy
someone full-time if there are multiple tanks.
Three commenters (IV-D-01 [Wenske], IV-D-05, IV-D-17)
-suggested that a statistically .significant increase or change in
surface tension should be the trigger for increasing the
measurement frequency; one commenter (IV-D-47) stated that
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surface tension does not change day-to-day or week-to-week. Two
commenters (IV-D-10, IV-D-43) stated that the monitoring schedule
for fume suppressants or alternate technologies (i.e., foam)
should be set throug-h permit review and be based on amp-hrs of
throughput, not on operating time. Another commenter (iv-D-58)
stated that the manufacturer's recommendations should be followed
and that, generally, daily or weekly testing is appropriate. One
commenter (IV-D-10) suggested that monitoring be based on
rectifier throughput. One commenter (IV-D-22) noted that
frequent monitoring results in increased exposure of workers to
hexavalent chromium.
Several commenters noted specific situations in which
monitoring every 4 hours is excessive. Three commenters
(IV-D-26, IV-D-48, IV-D-59) stated that sampling every 4 hours is
not necessary when chromium additions are performed
automatically; weekly sampling is sufficient in this situation
(IV-D-26, IV-D-59). One commenter (IV-D-25) indicated that if a
source uses a fluorocarbon chemical and provides evaporative
recovery of chromium dragout, surface tension changes occur very
slowly. The wetting agent is returned to the bath and is
virtually indestructible; in this situation, daily measurement is
sufficient. One commenter (IV-D-35) stated that their operation
is continuous with constant operation characteristics, and if the
alkaline baths are also covered by the rule, it would be more
appropriate to monitor once per day or when a new production is
introduced into the system.
One commenter (IV-D-22) indicated that because decorative
platers and anodizers make up only 10 percent of the emissions,
the proposed paperwork that applies to them is overkill; for
these sources, monitoring of baths once per week is sufficient.
Two commenters (IV-D-05, IV-D-17) stated that sampling
frequency should be dependent upon the surface tension a source
is attempting to maintain. Sampling every 4 hours is appropriate
when surface tension is maintained between 38-40 dynes/cm, if
the surface tension is between 36-38 dynes/cm, daily sampling is
sufficient, and if it is less than 36 dynes/cm, then weekly
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sampling is sufficient. According to one commenter, the language
in section 63.345(d) should be modified to reflect this
.dependency (IV-D-05).
Two commenters '{IV-D-18, IV-D-61) requested that the rule
clarify whether surface tension measurement occurs only during
hours of operation or whenever the tank is available for use; the
former of these would be preferred.
Response: The final rule specifies that monitoring of
surface tension should initially be done once every 4 hours, but
that the frequency may be decreased if no exceedances occur
during 40 hours of tank operation. The EPA had originally
proposed monitoring every 4 hours based on testing that indicated
' that the surface tension tended to increase at that point unless
additional wetting agent was added. In response to comments
received, the EPA recognizes that this frequency may be
burdensome, and in some cases, unnecessary. However, the EPA^has
insufficient data to establish the monitoring frequency that is
appropriate for each mode of bath operation. Instead, the final
rule allows a decrease in monitoring frequency if no exceedances
occur. Section 63.343 (c) (5)'(.ii) specifies that if no exceedances
occur during 40 hours of tank operation, monitoring can occur
once every 8 hours of tank operation. If there are again no
exceedances during 40 hours of tank operation, monitoring can
then occur once every 40 hours of tank operation. The minimum
frequency allowed by the rule is once every 40 hours of tank
operation. Also, once an exceedance occurs, the original
monitoring schedule of once every 4 hours must be resumed. A
subsequent decrease in monitoring frequency can occur according
to the criteria identified above. Likewise, if the bath solution
is changed out, the schedule must begin again at once every
4 hour. Documentation must be maintained on site to verify the
number of exceedances and that the appropriate monitoring
.-schedule is being followed.
As stated in a previous.response, the final rule is clear
that the emission limitations only apply during tank operation.
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Also, surface tension monitoring would only be required during
those times that the tank is operating.
2.11.4.4 Surface Tension Measurement Technique.
Comment; Four commenters provided comments on the
measurement technique for surface tension of tank baths. One
commenter (IV-D-09) suggestedthat stalagmometers, which are used
to measure surface tension, are not easy to use. Another
commenter (IV-D-22) stated that stalagmometers are time consuming
to set up, calibrate, and make a determination, and that
tensiometers, an alternative measurement device, are expensive.
This commenter and one other (IV-F-01 [Altmayer]) indicated that
alternative surface tension measurement methods that have
equivalent accuracy and repeatability should be allowed. One . .",.
commenter (IV-D-05) suggested that Method. 306B reflect different
sampling intervals for different ranges of surface tension.
Response: Measurement of the surface tension of tank baths
with a stalagmometer has been performed during several source
tests. For those commenters who believe that the stalagmometer
is not easy to use, section 3.1 of Method 306B states "...The
surface tension of the tank bath may be measured by using a
Preciser tensiometer, a stalagmometer, or any other device
suitable for measuring surface tension in dynes per
centimeter..."
The time interval for measuring surface tension has been
changed from once every 4 hour of tank operation to a progressive
system that minimizes measurements if the proper surface tension
is maintained. This system is described in section 3.2 of
Method 306B, and the maximum measurement interval is once every
40 hours.
For proper tank operation, the EPA believes that the surface
tension of the liquid in the tank must be maintained at 45 dynes
per centimeter or less. The surface tension of the tank solution
will fall into one of two categories: 45 dynes per centimeter or
less and greater than 45 dynes per centimeter. Different
sampling intervals for different ranges of surface tension would
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mean little and unnecessarily complicate the measurement
procedure.
2.11.4.5 Testing and Monitoring T?«=-gui remits for Sources
Using Foam Blankets.'
Comment: Thirteen commenters (IV-F-01 [Altmayer], IV-D-02,
IV-D-10, IV-D-20, IV-D-22, IV-D-25, IV-D-26, IV-D-37, IV-D-43,
IV-D-52, IV-D-57, IV-D-59, IV-G-01) provided remarks regarding
the burden of hourly testing for sources using foam blankets.
Commenters also questioned the testing method and recommended
alternative testing schedules.
Two commenters (IV-D-37, IV-D-43) stated that hourly
monitoring is excessive. Foam blankets that are used according
to operator's instructions are designed to last 24 hour, as long
as air agitation does not surface near the anodes and freeboard
height is adequate. These commenters said visual observation is
adequate for determining foam blanket effectiveness. One of
these commenters (IV-D-37) indicated that the rule could specify
the volume and frequency for additions of foam blankets based on
the surface area of the tank or the rule could specify that
manufacturer's recommendations be followed.
One commenter (IV-D-22) stated that hourly monitoring of
thickness is an undue burden and can be substituted with the use
of automated .feeders and ampere-hour monitoring. Another
commenter (IV-D-57) also stated that this is burdensome and noted
that other monitoring within the rule is proposed on a daily
basis. One commenter (IV-D-02) questioned the basis for
requiring hourly monitoring for foam blanket thickness. One
commenter (IV-D-52) indicated that the same level of
environmental protection could be achieved through weekly
monitoring.
Two commenters (IV-D-26, IV-D-59) suggested that it is
obvious that the EPA is trying to discourage the use of foam
blankets; these commenters note that several States recommend or
-require foam blankets with less testing and recordkeeping than
that proposed by the EPA. These commenters stated that the EPA
should consider eliminating the performance test requirement and
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should encourage foam blankets when wetting agents are not
feasible. Another commenter (IV-D-37) also indicated that foam
blankets are discouraged because of the burdensome monitoring
requirements; this is inappropriate because foam blankets are
effective pollution prevention techniques. One commenter
(IV-F-01 [Altmayer]) stated that the rule should not distinguish
between foam blankets and wetting agents. Two other commenters
(IV-D-10, IV-D-43) suggested the EPA increase the rule's
flexibility by allowing suppressant foams and plastic balls as
equivalent methods.
One commenter (IV-D-37) recommended that the rule not
ii-'!!;:, •• " „ ' '' '' 'l|'"'
require hourly monitoring of foam blankets when the tank is
unattended^ (i.e., overnight). Two other commenters (IV-D-25,
IV-D-37) also requested that exemptions be made for foam blanket
measurement for those times when the tank is idle, and time
should be allowed for the foam blanket to build up after the tank
has been left idle.
Two commenters (IV-D-02, IV-G-01) requested that the EPA
describe the method for measuring foam blanket thickness on
trivalent or hexavalent chromium baths. Two commenters (IV-D-20,
IV-D-43) requested that the rule clarify how sources using foam
blankets should establish the outlet chromium concentration,
especially if the tanks are not ventilated. Another commenter
(IV-D-59) stated that the stack testing requirement is
unreasonable as it can cost up to $10,000. Two commenters
(IV-D-20, IV-D-43) suggested section 63.343(b) specify that
sources complying by use of a foam blanket should establish a
foam blanket thickness as a site-specific operating parameter as
opposed to establishing a single default limit. These commenters
note that if section 63.343(d), which requests information on
alternate air pollution control devices that a source may be
using to achieve compliance, applies to foam blankets, then foam
blankets must be classified as air pollution control devices.
Respc-nse; The final rule is unchanged in that sources using
a foam blanket must conduct a performance test, and the initial
monitoring frequency is once per hour. However, as with wetting
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agents, if there are no exceedances of foam blanket thickness for
40 hours of tank operation, monitoring can occur once every
:4 hours. If there are no exceedances for 40 more hours of tank
operation, monitoring can occur once every 8 hours. The minimum
frequency specified for foam blankets is once per 8 hour of tank
operation. As with wetting agents, if there is an exceedance,
the original monitoring frequency of once per hour must be
resumed. A subsequent decrease in monitoring frequency can occur
in accordance with the criteria outlined above. If the bath
solution is changed out, the initial monitoring schedule of once
per hour must be resumed. The maximum frequency of 1 hour is
based on the EPA's experience that foam blankets can deplete
quickly and must be closely monitored.
The EPA believes that wetting agents are safer than foam
,,blankets because foam blankets present a potential safety hazard.
The foam traps the hydrogen gas and chromic acid mist in the foam
layer; if these gases build up and a spark is generated, a
hydrogen explosion will result. As a means of encouraging
wetting agent use over foam blankets, sources using wetting
agents do not have to conduct a performance test unless they want
to set a surface tension limit other than the default value of
45 dynes/cm. The EPA believes that the increased compliance
timeframes will allow sources that currently use foam blankets
the opportunity to explore the use of wetting agents. Sources
that wish to continue using foam blankets will be required to
conduct a performance test, and perform the necessary retrofit to
accommodate such a test. It is also important to note that
sources using a foam blanket in combination with a wetting agent
can demonstrate compliance through the surface tension limit.
Several commenters were concerned about the technique for
measuring foam blanket thickness, and the potential hazards
associated with this measurement. The EPA does not believe that
.it is necessary to specify a procedure because it is simply a
depth measurement. Specifying a technique may also hinder the
development of site-specific techniques to reduce worker
exposure. For example, a plastic ball of l-in. radius may be
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marked at the center and allowed to float on the liquid in the
tank. The foam blanket measurement could then consist of
ensuring that the foam is at the same level as the mark on the
plastic ball.
• ' ' ' ' '•' "-I
The final rule specifies that sources using foam blankets
are to establish foam thickness as the site-specific operating
parameter, and set the value of this parameter during the initial
performance test. Alternately, the default thickness of 1 inch
could be used as the compliant thickness. As such, § 63.343(d),
which specifies procedures to establish compliance monitoring for
control methods not identified in the rule, does* not apply.
2.11.5 Monitoring Requirements--General
Comment: One commenter (IV-D-02) questioned how the
$14 million and $1.6 million cost estimates were reached by the
EPA in predicting the rule's economic impact on industry to meet
the monitoring, recordkeeping, and reporting requirements for
compliance with chromic acid emission standards for hexavalent or
with surface tension levels for trivalent chromium. One
commenter (IV-D-28) found it unreasonable that in the EPA's cost
estimates, monitoring and recordkeeping constitute 28 percent of
the total annual cost. A commenter from the aerospace industry
(IV-D-47) is concerned that the small businesses that supply
products to the aerospace industry will not be able to afford the
technology to meet the standards. According to this commenter,
the impact of the regulation will be greater than the EPA's
estimate unless the standard is adjusted and the monitoring and
recordkeeping requirements are reduced. This commenter also
stated that the burden of monitoring, reporting, and
recordkeeping is underestimated and it will likely require
600 hours per year per source. Another commenter (IV-D-58)
suggested that the complicated monitoring, recordkeeping, and
stack measurement methods place an unreasonable economic burden
on small sources.
Response; The burden of monitoring, reporting, and
recordkeeping are estimated by the EPA based on the number of
measurements and records an owner would have to take, and the
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time to file reports to the permitting agency. The estimates
presented in the proposal preamble also include the burden of the
"initial performance test, and for a certain number of facilities,
'repeat tests in the event of failure.
As described in this section and in Section 2.13, the
monitoring, reporting, and recordkeeping requirements in the
final rule are less than what were proposed. The EPA reduced the
burden specifically due to the many area sources that will be
subject to these standards. The ongoing yearly cost of the final
monitoring, reporting, and recordkeeping is approximately
159,100 hours (or $3.5 million) for hard chromium electroplaters,
289,300 hours (or $6.4 million) for decorative chromium
electroplaters, >and 70,200 hours (or $1.6 million) for chromium
anodizers. The EPA believes that the monitoring, reporting, and
recordkeeping has been reduced to the extent possible while still
providing the EPA with the ability to determine a source's
compliance status.
Comment: One commenter (IV-G-01) requested that the EPA
clarify the monitoring to be performed when hard chromium
electroplating and chromium anodizing are performed in the same
tank. This commenter stated that in such situations the tank
should be considered in compliance if the surface tension limit
is met.
Response; As clarified in the final rule, the monitoring
requirements are specific to the type of control technique used,
not the type of tank operation. If hard chromium electroplating
and chromium anodizing are performed in the same tank, and a
wetting agent (or combination foam blanket/wetting agent) are
used to control emissions from the bath during both modes of
operation, surface tension monitoring is appropriate. However,
in accordance with the final rule, an initial performance test
-would have to be conducted to demonstrate that the emission limit
vis met when hard chromium electroplating is taking place.
:. Comment; Three commenters (IV-D-10, IV-D-42, IV-D-43)
suggested that the permitting agencies be allowed to identify
suitable monitoring for affected sources in their jurisdiction.
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One of these commenters (iv-p-io) recoinmended the frequency of
monitoring be based on permit review or a subcategory-specific
basis and also suggested that the requirements could be subject
to one-time public and Federal comment.
One commenter (IV-D-58) recommended the EPA develop a
two-tiered approach to monitoring requirements: one tier would
be low-burden for those sources that do initial performance
testing, O&M plans, and maintain compliance, and the second tier
would be more rigorous for sources that need moire scrutiny or
could be used as an enforcement option for the EPA. This
commenter also suggested facility certifications for small
facilities through industry-developed recommended-best-practices
and automated monitoring or recordkeeping could be employed in
lieu of the proposed requirements. This commenter recommended
that technical and compliance assistance for small businesses be
utilized under section 507 of the Act.
Response; The EPA recognizes that many State and local air
jn, ! , • sir'•! '
pollution control agencies have established monitoring,
reporting, and recordkeeping requirements for the sources covered
by the proposed standards. However, the EPA is required to
establish the minimum monitoring, reporting, and recordkeeping
requirements in the Federal rule that are necessary to determine
a source's compliance status at any given time. State and local
agencies reserve the right to require other types of monitoring,
reporting, and recordkeeping in addition to the requirements of
the Federal rule.
, The final rule contains fewer monitoring, reporting, and
recordkeeping requirements than the proposed rule and should
therefore alleviate some of the burden on small sources. The EPA
believes that any tiered compliance requirements would further
complicate the rule, making compliance by small sources more
difficult. In regard to the EPA actions for small businesses
under section 507, the EPA is developing an enabling document to
accompany the rule, and the Small Business Administration is
developing a pamphlet to assist small businesses. Both of these
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documents are intended to help sources understand the
requirements of the rule and implement the rule.
Comment; Two commenters (IV-D-20, IV-D-43) suggested that
all performance test" requirements establishing site-specific
operating parameters should be in one section of the rule, such
as section 63.343. One commenter (IV-D-24) suggested a specific
set of monitoring requirements be developed to address systems
using multiple technologies.
Response: The final rule has been reorganized so that
testing and monitoring requirements have been made more clear,
and also addresses sources that are using multiple technologies
to comply with the rule. All compliance monitoring requirements
are contained in § 63.343. All performance testing requirements
are in § 63.344.
Comment; One commenter (IV-D-61) pointed out that although
the term "operation of the tank" is referred to throughout the
monitoring requirements, the term is not defined. This term
could have several meanings, such as when the tank is heated to a
specific temperature, when it is charged, or when it contains
electroplating material. The commenter recommended that tank
operation be defined as when the contents of the tank reaches a
temperature greater than room temperature.
Response: In the final rule, tank operation is defined as
any time that current and/or voltage is being applied to a single
chromium electroplating or chromium anodizing tank or to any one
of a series of such tanks that are ventilated to a common control
device.
2.12 SELECTION OF TEST METHODS
2.12.1 Test Methods 306 and 306A
Comment; One commenter (IV-D-17) noted that Method 306
presents difficulties when the sample contains significant
quantities of dissolved salts. To alleviate this problem, the
commenter suggested the EPA modify Method 306 to allow use of a
rnitric acid/hydrogen peroxide matrix in lieu of the
sodium hydroxide/bicarbonate matrix. Another commenter (IV-D-53)
indicated that sodium hydroxide causes analytical difficulties
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and recommended using a 0.1 N solution. This commenter also
recommended that if a nitric acid solution is used, it should
also be used for calibration standards to minimize matrix
effects. The test methods in 40 CFR part 266, appendix IX and
SW846 Method 6010 should be allowed by the EPA as an equivalent
method (IV-D-17).
Comment; Two commenters (IV-D-10, IV-D-24) indicated that
the methods proposed in the rule for determining chromium
emissions, do not have detection limits low enough to determine
compliance with the standard. Both of these commenters indicated
that Method 306 is not appropriate for determining emissions at
very low levels and that the EPA provides no guidance on
extending the duration of the test run (increasing the sample
volume of air collected) or limiting the volume of probe wash
(less solvent) to decrease the level of detection for the method.
The other commenter (IV-D-24) pointed out that the proposed
emission standards for hard chromium sources are below the
detection limits of the proposed ICP analytical method. In fact,
using ICP with a concentration of 50 ug/L as a minimum
requirement, the method detects chromium concentrations at values
of 8 times greater than the standard. This commenter also
pointed out that the minimum detection limits for ICP and GFAAS
are not within the linear ranges for these methods.
Another commenter (IV-D-53) suggested use of an ICP/MS
system as an alternative method for detecting low concentrations.
Response: One commenter (IV-D-17) referred to the
difficulty of analysis when the sample contains significant
quantities of dissolved salts, and suggested using nitric
acid/hydrogen peroxide matrix in lieu of the sodium
hydroxide/bicarbonate matrix. If the dissolved salts make
analysis difficult, it has not made it difficult enough that the
labs that have done our analyses (and written the analysis
methods) have felt it necessary to point this out as a problem.
If a nitric acid/hydrogen peroxide matrix is superior to the
sodium hydroxide/bicarbonate matrix for analysis purposes, the
commenter may verify this possibility by performing a Method 301
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evaluation. The comment on the 0.1 N solution is difficult to
respond to because we use 0.1 N sodium hydroxide already and the
reference in the letter (IV-D-53) was not specific. Other
commenters recommending nitric acid in the analysis may also use
Method 301 to verify the validity of their suggestions. The
analytical method in 40 CFR part 266 (ICPCR) will be allowed for
hexavalent chromium analysis.
Other commenters stated that the "methods proposed for
determining emissions do not have detection limits low enough to
determine compliance with the standard. This comment doesn't
make any sense because EPA used these analytical methods to set
the standard (see Docket No: A-88-02 for an explanation of why
the colorimetric method was dropped in lieu of atomic absorption
graphite furnace (AAGF) or ion chromatography using a post column
reactor (ICPCR)). The reasons for using AAGF and ICPCR was to
increase the accuracy of the analytical technique and still
maintain a reasonable sample time. The suitability of the
detection limits can be illustrated with the following example
when using AAGF on an outlet location (ICPCR is even more
sensitive than AAGF).
A 2 hour sample would collect about 90 cubic feet of sample.
This 90 cubic feet is equal to 90 cubic feet times 0.02832 cubic
meters per cubic foot which equals 2.5488 cubic meters. If the
concentration of total chromium in this 2.5488 cubic meters of
sample were at the limit of the standard for large hard chromium
platers (0.013 mg/dscm), the sample would contain:
2.5488 m3 (0.013 mg/dscm) =
33.1 micrograms
of total chromium
The sensitivity of the AAGF method is 1 microgram per
1,000 milliliters. A sample containing 5 to 10 micrograms would
be quantifiable if the total sample collected was contained in
1 liter or less of solution. The maximum quantity of sample
solution would probably not exceed 800 milliliters, so 4 to
8 micrograms collected would be sufficient for a reliable
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analysis at the level of the standard, the 33.1 micrograms of
sample collected is 4 to 8 times the minimum catch for
quantifiability.
Perhaps the commenters were referring to the
diphenylcarbazide colorimetric method, or the ICP method. The
colorimetric method was replaced in 1991 because it was not
sensitive enough for some of the more recently developed control
systems. The ICP method which is mentioned in Method 3Q6 is good
for large concentrations of chromium, such as that collected at
the inlet to the control system. It is not suitable for
measuring outlet concentration that are very close to the
standard. The point about the length of the test is a valid one,
and we will specify a 2 hour test time at a sampling rate of
about 0.75 dscfm.
A commenter also stated that the minimum detection limits
for ICP and AAGF analysis methods were not within the linear
ranges for those methods. The detectable limits do not have to
be within the linear range. The quantifiable limits,- however,
are within the linear range. As mentioned before, the ICP method
is acceptable only for high concentration samples. The AAGF
analysis can detect l microgram per liter of total chromium. A
concentration of 5 to 10 micrograms per liter is quantifiable.
It is not likely that the impinger solutions and sample rinse
collected following sampling would exceed 1 liter. The combined
impinger solutions and sample rinse would probably be between
500 and 800 milliliters. It is also not likely that less than
4 to 8 micrograms of chromium would be caught in a 2 hour sample
that was taken at an extremely well controlled cutlet. If the
sample catch is less than 4 to 8 micrograms of chromium (per
800 milliliters of sample solution), or if the chromium cannot be
detected in a sample, the source would be well below the emission
limits established in the standard.
Comment: Five commenters (IV-D-10, IV-D-24, iv-D-37,
IV-D-49, IV-D-53) suggested changes or additions for Methods 306,
306A, and 306C. [Note; There is no method 306C in the proposed
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rule. The commenter appears to be referring to
section 5.1.1.2--Velocity Traverse section in Method 306A.]
One commenter (IV-D-24) requested that the EPA provide a
margin of error to reflect the precision of the sampling methods
and analytical test methods. One commenter (IV-D-10) suggested
the addition of a colorimetric analysis to Method 306 to provide
hexavalent chromium in addition to total chromium. This would
prevent a source that is subject to a State emission standard
based on hexavalent chromium from having to perform two source
tests. One commenter (IV-D-37) made the following suggestions
for Method 306: (1) the method should state that probe heat is
not necessary; (2) the method should state that use of probe and
nozzle brushes during recovery is unnecessary; and (3) the method
should suggest specific recovery procedures that minimize sample
volume.
One commenter (IV-D-53) made several remarks concerning
Methods 306 and 306A. For section 5 of Method 306, the commenter
suggested that trip blanks be used rather than reagent blanks
because the trip blanks provide more indication of contamination
problems. The results of blank runs should be reported if the
method does not specify a maximum acceptable blank level. The
commenter also suggested using more than 10 ml of acid to acidify
300 ml of 0.1 N sodium hydroxide. Also, the amount of dilution
allowed in bringing a sample into calibration range should be
limited. For section 7 of Method 306, the commenter recommends a
standard check every ten injections, or every set, whichever is
greater. According to the commenter, a quality control check
standard that is closer to the limit of detection would detect
nonlinearities on the lower end of the calibration curve; a
factor of 20 times the limit of detection may be more appropriate
than 100 times the limit of detection for a quality control check
standard. For Method 306A, the commenter recommends that
flexible tubing containing phthalate plasticizers not be used for
chromium sampling trains as it is mechanically sticky and
possibly reactive. One commenter (IV-D-10) indicated that
Method 306A would seem to result in only minimal cost savings
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compared to Method 306 and should be Devaluated before being
approved.
Another commenter (iv-D-49) suggested that Method 306C
should contain provisions for a 33 percent increase in pressure
in addition to the provisions for a 33 percent decrease in
pressure that the method currently contains. This commenter also
indicated that some newer control devices are basically
extensions of the hood ducting and may not have one diameter
between the hood and control device for insertion of the pitot
tube; an alternative velocity measurement point for Method 306C
should be specified.
Response: One commenter requested that the EPA provide a
margin of error to reflect the precision of the sampling methods
and analytical test methods. It is the EPA's opinion that
providing a margin of error to reflect the precision of the
sampling methods and analytical test methods would cost money,
take time, and would be nonproductive in view of. the fact that
future testing and analysis will be performed in a manner
consistent with that used to gather the data to establish the
standard. Another commenter also suggested adding a colorimetric
method to the analysis section of Method 306. The EPA has found
that the diphenylcarbazide colorimetric method the commenter is
probably referring to does not have the sensitivity required to
measure the low chromium concentrations found in the outlet stack
gases. However, the EPA has added the use of the ion
chromatography with a post-column reactor as an acceptable
analytical method for determining the hexavalent chromium
concentration in the exhaust stack.
One commenter made the following suggestions for Method 306:
(1) the method should state that probe heat is not necessary;
(2) the method should state that use of probe and nozzle brushes
during recovery is unnecessary; and (3) the method should suggest
specific recovery procedures that minimize sample volume. In
reviewing these comments, the EPA agreed that any mention of
probe heat and probe and nozzle brushes for sample recovery will
be deleted from the method. Regarding specific recovery
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procedures to minimize sample volume, the EPA believes that the
analytical methods have sufficient sensitivity to detect small
quantities of chromic acid collected and no procedures are
necessary to minimize sample volumes. On the contrary, the EPA
believes such procedures could increase the risk of missing part
of the sample collected. The EPA checked the sensitivity of the
methods against 1 liter of collected sample solution in order to
determine if longer sample times were necessary to ensure
sufficient sample collection. The results of this sensitivity
indicated that a 2-hour sample collects a sufficient quantity of
chromic acid mist for accurate determination of concentration in
mg/dscm.
Another commenter indicated that Method 306A would result in
minimal cost savings to the industry. For the response to this
comment, please refer to section 2.12.3.1. In addition, another
commenter (IV-D-49) suggested that Method 306C should contain
provisions for a 33 percent increase in pressure in addition to
the provisions for a 33 percent decrease in pressure that the
method currently contains. Please refer to the response to
comments on Method 306A in section 2.11.2.3 for the response to
this comment. The monitoring equipment (magnahelic gauges and
pitot tubes) are used to assess system operation, and accuracy is
not as important as reproducibility. A magnahelic gauge is easy
to adjust by securely mounting the gauge and adjusting the gauge
to "zero."
Comment; Three commenters (IV-D-10, IV-D-14, IV-D-47)
requested that GARB Method 425 be evaluated for equivalency, and
if determined to be equivalent, be identified as such in the
rule. These commenters also stated that sources that have
performed this test should not have to retest. Two of these
commenters (IV-D-14, IV-D-47) and one other (IV-D-15) pointed out
that ion chromatography is the preferred analytical method and
should be cited as equivalent in the rule. One of these
commenters (IV-D-10) indicated that Method 306A is not acceptable
for demonstrating compliance with California chromium
electroplating emission limits.
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Four commenters (iv-D-06, IV-D-io, IV-D-14, IV-D-27) asked
whether retesting will be required if sources have done previous
performance testing using 306, 306A, or an equivalent test
method.
Response; The GARB Method 425 train is almost identical to
the Method 306 train except that a filter is used between the
third and fourth impingers. The catch on these filters is
usually nondetectable. There is no need to evaluate the GARB
sampling train for equivalency. The analytical method used after
the sample is collected needs tobe considered. In the early
days of the NESHAP development, the analysis for hexavalent
chromium using either the Method 306 train or the GARB 425 train
was the diphenylcarbazide colorimetric method. As control device
efficiency improved, the colorimetric method was not sensitive
enough toensure accuracy without going to excessively long
sampling times. The acceptability of previously performed GARB
Method 425 tests will depend upon the analysis rather than the
sampling train or the sampling procedure. For GARB tests using
the colorimetric method for analysis, the sample catch will have
to be at least 5 times the minimum detection limit to be
acceptable. The GARB method is sensitive to 0.33 micrograms per
100 milliliters. To ensure that the data are accurate to within
± 10 percent accuracy, the concentration at the detector would
have to be 5 times 0.33 micrpgrams per 100 milliliters or
1.65 micrograms per 100 milliliters. Because the sample is
diluted to 1/2 the original concentration prior to analysis, the
sample solution recovered from the train must contain
3.30 micrograms per 100 milliliters, or 0.033 micrograms per
milliliter. If the sample meets these concentration
requirements, the colorimetric method of analysis for hexavalent
chromium, and consequently, the results, may be accepted. If the
sample does not meet these criteria, it is not possible to assure
±10 Percent accuracy. If another type of analysis is used, such
as atomic absorption graphite furnace for total chromium, or ion
chromatography with a post column reactor for hexavalent
chromium, there should be no problem using GARB Method 425.
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One commenter said that ion chromatography was the preferred
analytical method, and this is true if this means ion
chromatography with a post column reactor (ICPCR)• I°n
chromatography with a post column reactor is the preferred
method, but finding a laboratory with this analytical capability
is difficult. Nonetheless, the final rule will be revised to
include ICPCR as an acceptable analytical method.
The commenter who stated that Method 306A was unsuitable for
demonstrating compliance with the California standard was
incorrect. The commenter suggested that Method 306A should be
thoroughly compared with Method 306 before it is officially
approved. Method 306A has been carefully compared against
Method 306 and is, in fact, suitable for showing compliance with
the California standard.
Four commenters asked whether retesting will be required if
sources have done previous performance testing with Method 306,
306A or an equivalent test method. Tests using other equivalent
sampling methods for chromium emissions should be reviewed by the
Agency prior to determining whether or not another test should be
performed in accordance with § 63.344 (c) (4) of subpart N and
§ 63.7 (f) of subpart A. Facilities that use Method 306A prior to
December 1991 will have to retest.
2.12.2 Demonstrating Compliance When Using Fume Suppressants
Comment; Two commenters (IV-D-22, IV-D-59) questioned
whether facilities will have to measure emissions to support
meeting the emission standard for fume suppressants. Language in
the preamble to the proposed rule on pages 65772 and 65774
implies that facilities using fume suppressants are expected to
achieve a specific outlet concentration.
Response; The final rule includes a dual standard for
sources performing decorative chromium electroplating and
chromium anodizing operations. These sources must either:
(1) discharge no greater than 0.01 mg/dscm of total chromium to
the atmosphere, or (2) operate the electroplating or anodizing
tank such that the surface tension does not exceed 45 dynes/cm.
With the first alternative, a source must conduct a source test
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in accordance with the methods identified in the rule to
demonstrate that the emission limit of 0.01 mg/dscm is not being
exceeded. It is assumed that a source complying with the first
alternative is using" an add-on control device or a foam blanket.
With the second alternative, a source must measure surface
tension po demonstrate .initial compliance; ongoing compliance is
also demonstrated through surface tension measurement in
accordance with the monitoring procedures in § 63.343 (c) of the
final rule. In this latter case, an initial performance test is
not required if the criteria of § 63.343(b)(2) are met. That is,
the source is a decorative chromium electroplating or chromium
anodizing tank, a fume suppressant containing wetting agents is
used to limit chromium emissions, and the owner or operator of
the source accepts 45 dynes/cm as the surface tension value that
demonstrates compliance with the standard. The rule is written
as an either/or alternative; that is, only the emission limit or
the surface tension limit must be met. It was not the EPA's
intent to require a source test if the criteria of § 63.343(b)(2)
are met. The EPA recognizes that for some decorative chromium
electroplaters and chromium anodizers source testing is not
feasible because ventilation stacks do not exist. Therefore, the
surface tension alternative is provided.
One exception to the above conditions is the case in which
sources using wetting agent-type fume suppressants want to
establish a surface tension limit other than the 45 dynes/cm
limit in the final rule. In such a case, a source would have to
conduct a performance test to establish the alternate surface
tension value that corresponds to the emission limit of
0.01 mg/dscm.
Sources performing hard chromium electroplciting that use a
fume suppressant (either a wetting agent, a foam blanket, or a
combination) to comply with the standard will have to conduct an
initial performance test to demonstrate compliance with the
standard. The EPA did not fully evaluate the use of fume
suppressants to reduce emissions from hard chromium
electroplating tanks because only a limited number of operations
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used this technique. Also, there were safety concerns associated
with their use, as well as the fact that fume suppressants are
not universally applicable to all types of hard chromium plating
operations. Therefore, all hard chromium electroplating tanks,
regardless of the type of control technique employed (e.g., APCD,
fume suppressant, or combination) must conduct an initial
compliance test. All hard chromium electroplating tanks will
have ventilation stacks to comply with OSHA requirements. Thus,
source testing will not be as burdensome as it would be for
decorative chromium electroplating and chromium anodizing tanks
that may not have ventilation systems. Ongoing compliance
monitoring will be the same for all tanks using fume
suppressants, requiring sources to monitor bath surface tension
if a wetting agent is used and foam blanket thickness if a foam
blanket is used.
2.12.3 Demonstrating Compliance When Using Add-On Controls
2.12.3.1 Impacts of Stack Testing.
Comment: Five commenters addressed the burdens associated
with stack testing. Two commenters (IV-D-06, IV-D-40) stated
that stack testing is burdensome and can cost up to $8,000
(IV-D-06) or more than $10,000 (IV-D-40). Onecommenter
(IV-D-59) stated that stack testing costs could close some
decorative chromium electroplating sources. Another commenter
(IV-D-47) suggested that stack testing be minimized because not
all control systems were designed to allow easy measurement of
outlet concentration, and alterations that may be necessary to
enable the performance of the testing (e.g., stack may need to be
extended) could be significant. Onecommenter (IV-D-53) stated
that the proposed method requires burdensome, yearly testing and
indicated that the process emission rate (mg/amp-hr) can be used
to demonstrate the correlation between compliance and the
applicable emission limit. This commenter states that with a
mg/amp-hr limit, 'compliance can be easily verified without a
source test. Another commenter (IV-D-42) stated that the EPA
needs to specify the initial performance test to demonstrate
compliance and set enforceable operating parameters and to
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evaluate the economic impact of such requirements because these
requirements may significantly hinder small sources.
Response; Based on the comments received at proposal, there
appears to be some confusion surrounding the stack testing
requirements. First, an annual test is not required. All
sources are required to conduct an initial performance test
within 18.0 days after the compliance date in accordance with
§63.7 °| the General Provisions to part 63, unless the criteria
of § 63.343(b)(2) are met. After the initial test, ongoing
compliance is demonstrated by performing compliance monitoring in
accordance with § 63.343(c) of the final rule. In terms of
modifications necessary to conduct a performance test, the method
in the rule requires that the stack height be 2.5 times the stack
diameter, not 8 times as thought by commenter IV-D-47. The EPA
has estimated the cost to conduct performance tests at all sizes
of sources and this cost was considered in selecting the
standard. The EPA recognizes that testing may be a burden for
some sources, and has pursued methods to reduce this burden. For
example, in developing the proposed rule, the EI?A found that the
analytical methods for measuring chromium emissions were
expensive, and the number of laboratories qualified to do the
testing limited. Therefore, the EPA developed and proposed
Method 306A, which is simpler and less expensive that other
methods. Based on a review of stack testing costs, the EPA has
determined that the cost for stack testing is approximately
$4,500 per stack. The EPA is aware of firms that may charge as
much as $8,000 to $10,000 per stack. However, it is up to the
owner of the electroplating facility to ensure they are paying a
fair competitive price for the stack test. In addition, the EPA
is aware of the fact that even $4,500 per stack could be
burdensome to some small plating shops. Furthermore, if the
initial test reveals that the control device is inadequate, and
modifications must be made to the system, the cost of an
additional test is incurred. To respond to these concerns, the
EPA developed the alternative Method 306A. The cost of
fabricating a Method 306A sampling train is about $600. A pitot
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tube (which can later be used for enhanced monitoring), a
manometer, and chemicals should run another $50. Three sampling
runs will take about 15 hour, which at $12/hour would cost $180.
The analysis of three samples and a blank would cost about
$60/sample for a total chromium analysis and would cost about
$80/sample for a hexavalent chromium analysis. The cost of
having the company perform its own test is:
Sampling train: $600.00
Pitot, manometer, chemicals: $50.00
Labor $180.00
Analysis $320.00
Total $1150.00
The company also gets to keep the equipment. Additional
testing then costs $500 for labor and analysis plus about $10 for
chemicals, or $510.
If the company does its own testing and performs only one
test, it saves $3,350 over having a testing firm do the work. If
two tests are needed, the company saves the original $3,350 plus
$3,990 or $7,340. If the company has more than one stack, it
would definitely pay the company to do its own testing. A major
airline company used Method 306A to test its plating tanks and
saved over $33,000 in source testing costs.
When the final rule is in place, there will probably be some
companies that will rent Method 306A equipment. Stack testing
firms may also use Method 306A for sampling sources and still use
their isokinetic equipment. This should be less expensive for
the plater because Method 306A is less labor intensive and easier
to perform that Method 306. There may also be equipment
manufacturing companies that will sell assembled trains ready for
use.
Another way to alleviate the expense of testing so many
platers would be for one of the trade associations to set up its
own source sampling group, dedicated to sampling the
electroplating and anodizing industry. A competent individual
well versed in chromium sampling and knowledgeable of the methods
could head up such a group and save the industry considerable
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money. To further assist sources in using the Method 306A
sampling train, the EPA has developed a video entitled
"Construction and Operation of the EPA Method 306A Sampling Train
and Practical Suggestions for Monitoring of Electroplating and
Anodizing Facilities." This tape will be available in
January 1995 for a nominal fee through North Carolina State
University, Registrar, Environmental Programs, Box 7513,
Raleigh, NC 27695-7513. The telephone number is (919) 515-4659;
the fax number is (919) 515-4386.
Also, the EPA believes that extending the compliance time to
1 year for decorative chromium electroplaters and 2 years for
hard chromium electroplaters and chromium anodizers will provide
sources with more time to obtain capital for both control device
purchase and performance testing. Finally, § 63. 344 (b) of
subpart N allows sources to fulfill the initial compliance test
requirements for this standard by submitting compliance test
results from tests conducted at startup in accordance with State
operating permits. The test must have been conducted -using the
EPA- approved test methods and procedures in subpart N. This
provision may offer some relief to sources that have recently
conducted performance tests.
One commenter (IV-D-53) also suggests that an annual source
test is nqcessary to demonstrate compliance with a
concentration-based standard, whereas compliance with a mg/amp-hr
standard can be demqnstrated without a performance test. As
explained above, an annual test is not necessary. Also, the
format of the standard is irrelevant to performance test
requirements. For the reasons described in Section 2.7,
Selection of the Format of the Standard, the EPA has promulgated
a rule expressed in mg/dscm. However, even if the rule had been
expressed in mg/amp-hr, the EPA would have required a source test
to demonstrate initial compliance and parametric monitoring to
demonstrate ongoing compliance. Thus, the format of the standard
has no bearing on the source test requirements.
In regard to the comment that the EPA should specify the
initial performance test and set enforceable operating
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parameters, the final rule explicitly requires an initial
performance test except as allowed by § 63.343(b)(2) and (3).
The EPA has also specified which operating parameters correlate
to compliance with the emission limit. For example, the pressure
drop is directly related to the performance of a composite mesh-
pad system. The EPA does not, however, think it is appropriate
to identify the operating parameter value. The final rule allows
sources to set the operating parametef value during the initial
performance test because each control system is different
depending on its design, age, operation, and condition. Rather
than hindering small sources, the EPA believes that this
condition lends flexibility to all sources. The final rule does
specify default compliant ranges. For example, a source is in
compliance if the measured pressure drop value is within ± 1 inch
of water column from the average value established during the
initial performance test, and a source is in compliance if the
measured velocity pressure value is within ± 10 percent of the
average value established during the initial performance test.
These ranges have been specified because EPA recognizes that it
would be difficult to set a range of compliant operating
parameter values during one performance test. For those owners
or operators that wish to establish their own range of compliant
operating parameter values, the final rule allows them to do this
by conducting multiple performance tests. The following comment
and response discuss the importance of compliance testing for all
sources, regardless of size.
Comment: One commenter (IV-D-57) suggested that at large
sources where many tanks have identical design, a compliance test
protocol that requires a source to test a percentage of the
comparable tanks may be more practical. Two commenters (IV-D-27,
IV-D-36) requested that the EPA allow a source to test one
representative unit to demonstrate compliance for several similar
units. Another commenter (IV-D-40) suggested that the EPA
certify commonly used control devices based on the EPA's test
methods to avoid compliance testing by small businesses.
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Response; The EPA does not believe that representative
testing is adequate to demonstrate that each source is in
compliance with the standard. Therefore, the final rule requires
that each source conduct a performance test to demonstrate
compliance with the emission limit, unless the source is
performing decorative chromium electroplating or chromium
anodizing and is complying with the surface tension limit. Based
: , - ,, " • .in „ , , " ii.,,,1' '
on the EPA's experience testing control devices in use in this
industry, a device's performance will vary based on its age, its
condition, and the manner in which it is maintained and operated.
A performance test is also necessary for sources to establish the
Val!3es f3* the °Peratin£r parameters that will be monitored to
establish continuous compliance. For example, a source operating
a composite mesh-pad system will have to establish the pressure
drop value that corresponds to the emission limit.
2.12.3.2 Control Systems Controlling Multiple Tanks.
Comment; Two commenters (IV-D-36, IV-D-44) requested that
the rule provide guidance on how to verify compliance when both
chromium anodizing and hard chromium electroplating tanks are
vented toa common control device. Three commenters (IV-D-17,
IV-D-47, IV-D-61) pointed out that the regulation does not
account for the situation in which chromium electroplating
sources share a ventilation system with nonchromium sources that
could introduce dilution air; these commenters questioned where
the emissions should be measured. Three commenters (IV-D-47,
IV-D-52, IV-D-61) noted that it is extremely difficult to
reconfigure the existing system such that only the air from
chromium electroplating or anodizing will be tested. One of
these commenters (IV-D-61) indicated that tanks cannot be
selectively turned off to accommodate individual testing; some
air flow would still come from each tank.
Response; There are basically two situations involving
multiple tanks manifolded to one control system: (1) the
multiple tanks include a chromium electroplating or chromium
anodizing tank among other tanks not affected by the rule; or
(2) the multiple tanks include chromium tanks performing
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different operations (e.g., electroplating and anodizing) or the
same type of tanks subject to different emission limits (e.g., a
new hard chromium electroplating tank with an existing small,
hard chromium electroplating tank). The final rule includes
compliance provisions for either of these situations.
In the first situation, a chromium electroplating or
anodizing tank is tied to a control system that is also
controlling tanks that are not covered by this rule. In such a
case, the nonaffected tanks may be turned off, but air flow will
still result from each tank thus diluting the chromium measured
at the outlet from the control device. The final rule contains a
new procedure for estimating emissions for these special cases. ^
When multiple affected sources performing the same type of
operation and subject to the same emission limitation are
controlled with a common add-on air pollution control device that
is also controlling emissions from sources not affected by these
standards, the following procedures should be followed to
determine compliance with the applicable emission limitation:
1. Calculate the cross-sectional area of each inlet duct
(i.e., uptakes from each hood) including those not affected by
the standard.
2. Determine the total sample time per test run by dividing
the total inlet area from all tanks connected to the control
system by the total inlet area for all ducts associated with an
affected source, and then multiply this number by 2 hours. The
calculated time is the minimum sample time required per test run.
3. Perform Method 306 testing and calculate an outlet mass
emission rate.
4. Determine the total ventilation rate from the affected
sources by using equation 1:
IDA-
IATOTAL
(1)
where VRtot is the average total ventilation rate in dscm/min for
the three test runs as determined at the outlet by means of the
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Method 306 testing; IDA± is the total inlet area for all ducts
associated with affected sources; lAp^^ is the sum of all
inlet duct areas from both affected and nonaffected sources; and
winlet is the totar ventilation rate from all ducts associated
with the affected sources.
5. Establish the allowable mass emission rate of the system
(AMRgyg) in milligrams of total chromium per hour (mg/hr) using
equation 2:
EVRinlet x EL x 60 minutes/hour = AMR.
sys
(2)
where 2VRinlet is the total ventilation rate in dscm/min from the
affected sources, and EL is the'applicable emission limitation. *
The allowable mass emission rate calculated from equation 2
should be equal to or less than the outlet three-run average mass
emission rate determined from Method 306 testing in order for the
source to be in compliance with the standard.
The second situation likely to be encountered in industry is
one in which affected sources in two different source categories,
or £!ource.s. in the same source category (i.e., hard chromium
plating) but subject to different emission limits (i.e., new
versus existing small tanks), are tied into the common control
device. For example, a control system may be controlling
emissions from a hard chromium electroplating ta.nk, a chromium
anodizing tank, and other nonaffected sources. A similar
procedure as outlined above is followed, except that the
allowable mass rate is the sum of the chromium mass emission
rates calculated by equation 1 for each source category or group
of affected sources subject to the same emission limitation. For
example, assume that a control device controls emissions from a
chromium anodizing tank with a ventilation rate of 140 dscm/min
and a hard chromium electroplating tank at a large facility with
a ventilation rate of 75 dscm/min. The allowable chromium mass
emission rate is calculated as:
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[ (140 dscm/min) (0.01 mg/dscm) + (75 dscm/min)
(0.015 mg/dscm)] * 60 min/hr = 15'2 mg/hr
The. calculation is based on a 0.01 mg/dscm limit for the chromium
anodizing tank and a 0.015 mg/dscm limit for the hard chromium
electroplating tank. Thus, the allowable chromium mass emission
rate is 152 mg/hr.
The allowable chromium mass emission rate and operating
parameter values established for a control system that controls
multiple tanks described by either of the above situations are
valid only for that specific control system and tank
configuration. Therefore, if a tank is added to or removed from
the control system, a performance test must again be conducted to
establish the allowable mass rate and the operating parameter
values. This must be done whether or not the tank added or
removed is an affected tank; although nonaffected tanks will not
affect the allowable chromium mass emission rate, the operating
parameter value would be different. Retesting would not be
required if a nonaffected tank is replaced with a tank that is
the same size and is connected to the control system through the
same size inlet duct.
2.13 SELECTION OF REPORTING AND RECORDKEEPING REQUIREMENTS
2.13.1 Reportina/Recordkeepina Associated With Fume Suppressants
Comment; Seven commenters (IV-D-17, IV-D-24, IV-D-26,
IV-D-37, IV-D-45, IV-D-58, IV-D-59) stated that the types of
records that the rule requires sources to maintain are
inappropriate.
Five commenters (IV-D-17, IV-D-24, IV-D-26, IV-D-45,
IV-D-59) pointed out that requiring facilities to maintain
records of the amount of chemicals used and purchased does not
indicate compliance and should not be required. Another
commenter (IV-D-37) suggested that this requirement be made more
flexible by allowing sources to retain copies of purchase orders,
packing slips, etc., because in some large procurement systems,
the purchaser does not receive copies of the invoices.
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Fourcommenters (IV-D-24, IV-D-26, IV-D-58, IV-D-59)
indicatedthat requiring facilities to maintain records of the
frequency of maintenance additions and the amount of fume
suppressant material' added is not related to compliance and
should not be required.
Two commenters (IV-D-26, IV-D-59 ) stated that recordkeeping
requirements be limited to only surface tension measurements
because this measurement is the basis of compliance.
ResP°nse: In- finalizing the rule, the EPA attempted to
reduce the recordkeeping burden to the extent possible, while
still requiring sources to maintain sufficient records to
demonstrate compliance. The recordkeeping requirements are
contained in § 63.346 of the final rule. Recordkeeping
associated with fume suppressants requires that sources maintain
records of the date and time of surface tension or foam blanket
thickness measurements, as appropriate, and the value measured,
and the date and time of additions of fume suppressants to the
bath. The EPA concurs that the records required to be kept
should correspond specifically to that which is required to
demonstrate compliance. As such, records of fume suppressant
purchases and the amount added to the bath are no longer
required.
2.13.2 Reporting Frequency
Cornme.nt: SJ-X companies (IV-D-06, IV-D-07, IV-D-10, IV-D-18,
IV-D-27, IV-G-01) provided comments on the reporting frequency.
Five commenters suggested that the frequency of reporting
outlined in the proposed rule was burdensome. One of these
commenters (IV-D-06) indicated that neither quarterly nor
semiannual reporting is necessary; two commenters (IV-D-18,
IV-G-01) suggested that this reporting schedule be replaced with
a requirement that the source submit an annual certification that
necessary control parameters have been met, consistent with the
annual certification requirements of title V. One of the
commenters (IV-D-27) suggested semiannual compliance reporting
would be appropriate because it is consistent with the title V
operating permit program. Another of these four commenters
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(IV-D-10) indicated that sources should not have to submit
compliance reports if the source's permitting agency inspects the
onsite records on an annual basis.
One commenter CIV-D-07) suggested that the rule require
quarterly reporting until 2 years pass without exceedances of any
state or federal emission standards; after 2 years pass without
an exceedance, the source would be allowed to report semiannually
until a subsequent exceedance.
Response: The final rule requires submission of ongoing
compliance status reports to document whether a source has been
in continuous compliance with the standards. The final rule
contains different reporting schedules for major and area
sources. Major sources are required to submit ongoing compliance
status reports semiannually, unless an exceedance occurs. If an
exceedance occurs, quarterly reports are required. This change
reflects changes made to the General Provisions, which were only
a proposal when this rule was proposed. For major sources, the
reporting requirements in the final rule are analogous to those
in the final General Provisions.
In an effort to reduce the burden on area sources, the final
rule allows area sources to complete an annual compliance report,
and allows the source to maintain the report on site, to be made
available to the Administrator or permitting authority upon
request. The EPA recognizes that many permitting authorities are
not equipped to handle reports from area sources, and that these
sources may not be the sources of primary concern to the
authority. However, the requirements in the final rule do not
alleviate affected area sources from complying with the reporting
requirements of State or Federal operating permit programs under
title V. The rule does require that area sources submit reports
semiannually if exceedances occur, or if required by the
Administrator or permitting authority.
The rule also contains provisions for a reduction in
reporting frequency for those major and area sources that are
required to submit quarterly and semiannual reports,
respectively. These sources must have 1 full year of compliance
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with the standards, and request to have reporting frequency
decreased. The Administrator (or permitting authority) may grant
or deny the request.
2•13•3 Reporting and Recordkeepina Requirements--General
Comment; Seven commenters (IV-D-10, IV-D-22, IV-D-23,
IV-D-36, IV-D-47, IV-D-52, IV-D-58) indicated that the reporting
and recordkeeping requirements of the proposed rule are
burdensome for both small and large facilities and suggested the
EPA consider the impact of these requirements.
Two commenters (IV-D-10, IV-D-43) explained that small
businesses do not have the resources to keep extensive records
and to submit reports. According to these commenters, extensive
data may be necessary to maintain federal enforceability, but the
data is not needed for small businesses because the EPA is
unlikely to seek enforceable action against such a small firm.
One commenter (IV-D-58) said that the complicated monitoring,
recordkeeping, and stack measurement methods place an
unreasonable economic burden on small sources. One commenter
(IV-D-22) indicated that the EPA's reporting and recordkeeping
cost estimate of $14 million does not account for the negative
financial impact on small shops that do not have personnel
availableto perform testing every four hour.
Another commenter (IV-D-47) suggested that the EPA's
estimate q,f the burden of monitoring, reporting, and
recordkeeping has been underestimated and provided an industry
estimate of 600 hours per year per source for these requirements.
This commenter pointed out that, based on the EPA's estimate of
recordingand recordkeeping costs, for chromium anodizing sources
alone, the reporting and recordkeeping requirements will cost
almost $1 million per ton of reduction. The commenter also
indicated that the aerospace industry is concerned that the small
businesses that supply products to the aerospace industry will
not be able to afford the technology to meet the standards. The
impact of the regulation will be greater than the EPA's estimate
unless the standard is adjusted and the monitoring and
recordkeeping requirements are reduced. This coimmenter stated
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that the EPA should consider eliminating most of the reporting
and recordkeeping requirements for area sources.
One commenter (IV-D-23) pointed out that the EPA has
recognized differences in large and small facilities in selecting
MACT emission standards. The EPA should also recognize
differences between large and small facilities in selecting
reporting, recordkeeping, and permitting requirements. The
commenter suggested the following for small, hard chromium
platers: (1) exemption (especially for sources using batch
operations) from startup/shutdown requirements of the proposed
General Provisions; (2) exemption from extensive preconstruction
review requirements (even though the proposed General Provisions
include area sources, the intent of the Act was to include
construction and reconstruction of major sources only); and
(3) exemption from obtaining a title V permit.
One commenter (IV-D-36) explained that reporting and
recordkeeping will also be substantial for large companies where
multiple sets of records will be maintained at multiple
facilities across the nation. One commenter (IV-D-52) indicated
there is no environmental benefit to keeping records of gas
velocities, pressure drops, washdown conditions, and scrubber
water chromium concentrations.
Response: The EPA recognizes that the reporting and
recordkeeping contained in the proposed rule could be burdensome
for many sources, especially area sources. Given the large
number of area sources in these source categories, the final rule
contains reporting and recordkeeping requirements that are
substantially reduced from those required at proposal.
Specifically, the amount of records that a source is required to
maintain has been reduced, the frequency of reporting has been
reduced (especially for area sources), and the requirements of
the General Provisions have been further evaluated to assess
their applicability to these source categories. Where
requirements of the General Provisions were considered redundant
or confusing, subpart N has overridden the requirement as
specified in Table l of the final rule. For example, the
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requirements of § 63.6(e) of the General Provisions associated
with the startup, shutdown, and malfunction plan have been
overridden. Sources subject to subpart N are required instead to
complete an O&M plan in accordance with § 63.342(f)(3), with
ji, iiinj , , , . . i'.in
fewer elements than that required by the startup, shutdown,
malfunction plan. Also, the preconstruction review requirements
of the General Provisions have been overridden, and instead more
straightforward preconstruction review requirements are contained
in subpart N. Finally, as previously described in Section 2.11,
ii" ( •• _ |Y ' : ,. • • "i.. . • , >• •, • i,
the monitorxng requirements have been reduced where possible.
The EPA estimates that, on an ongoing basis, the impacts of
the revised reporting and recordkeeping requirements are
$3.5 million and 159,100 hours per year for hard chromium
electroplating operations, $6.4 million and 289,300 hours per
year for decorative chromium electroplating operations, and
$1.6 million and 70,200 hours per year for chromium anodizing
operations. This is compared to the impacts of the proposed rule
of $8.6 million and 388,400 hours per year for hard chromium
electroplating operations, $15.6 million and 706,200 hour per
year for decorative chromium electroplating operations, and
$3.8 million and 171,500 hour per year for chromium anodizing
operations.
Comment; Two commenters (IV-D-10, IV-D-43) stated that
state and local permitting agencies should be allowed to
determine appropriate reporting and recordkeeping requirements,
especially for area sources because enforcement actions against
area sources are the responsibility of local agencies. These
commenters also recommended that no reports be submitted for a
set period of time following promulgation; one commenter
suggested 6 months (IV-D-10) and the other suggested l year
(IV-D-43) as an appropriate timeframe. This would allow State
and local agencies an opportunity to request and assume
delegation of the air toxics program and to minimize the
confusion on the part of sources as to which agency has
authority.
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Response; The EPA is required to identify the minimum
reporting and recordkeeping requirements that are necessary to
determine compliance with subpart N. State and local agencies
may choose to require additional reporting and recordkeeping if
they feel it is necessary to determine the compliance status of a
source. States that currently have existing regulations for
chromium electroplating and anodizing tanks may submit their
programs to the EPA for approval as equivalent in accordance with
subpart E of part 63.
In the final rule, the first report that must be submitted
is the initial notification report required by § 63.347(c), which
is due to the Administrator 180 days after the effective date.
The report may be submitted to the permitting authority, if the
authority has been granted approval to implement and enforce this
rule. The compliance date for existing sources subject to this
rule is 1 year from the effective date for decorative chromium
electroplaters (i.e., November 1995) and 2 years from the
effective date for hard chromium electroplaters and chromium
anodizers (i.e., November 1996). The EPA believes that this
timeframe is sufficient for States to apply for implementation
and enforcement responsibilities for this rule.
Comment: One commenter (IV-D-10) suggested the length of
time a facility is required to keep records should depend on its
inspection frequency; however, records should be maintained for a
minimum of 2 years. A tiered approach to reporting frequency
based on the facility's emission level could also be adopted.
Two commenters (IV-D-24, IV-D-58) stated that maintaining records
at a facility for 5 years is excessive; a more appropriate length
of time would be 3 years.
Response: The final rule requires that owners or operators
of affected sources maintain records for a period of 5 years
following each occurrence, measurement, maintenance, corrective
action, report, or record. This requirement is unchanged from
the proposed rule because it is consistent with the General
Provisions and with the title V permit program. As stated in the
preamble to the final General Provisions, the EPA believes
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retention of records for 5 years allows the EPA to establish a
source's history and pattern of compliance for purposes of
determining the appropriate level of enforcement action.
Allowing the destruction of potential evidence of violations may
prevent the EPA from pursuing the worst violators.
Comment; One commenter (IV-D-20) asked that section 63.9(b)
specify that all sources are allowed to report potential
rectifier capacity or some other parameter in lieu of chromium
emission estimates.
Response: Section 63.9(b) of subpart A requires an initial
notification, but does not require that the emissions from the
affected source be estimated. In any event, § 63.9(b) has been
overridden by § 63.347(c) of the final rule. This section
requires identification of facility name and address, a statement
that subpart N is the basis for the notification, a description
" ' "" t
of affected sources and the applicable emission limitation for '
the source, and a statement of whether the source is located at a
major or area source as defined in § 63.2 of subpart A. For
owners or operators performing hard chromium electroplating, the
maximum potential rectifier capacity associated with these
operations must also be reported so the Administrator (or
permitting authority) knows if the source(s) is located at a
small or large, hard chromium electroplating facility. The
initial notification does not require an emissions estimate
because the affected sources in these source categories are
relatively uniform in terms of emissions potential.
Comment; One commenter (IV-D-38) explained that
automatic/continuous monitoring of conductivity, washdown timer,
magnahelic gauges, etc. may be equipped with a transmitter and
programmable logic controller system to provide printing and
storage of parameters that can be maintained via computer hard
drive. If the EPA approves the use of such a monitoring system,
software can be written to accomplish the storage of data on the
computer hard drive.
Response: Section 63.10(b)(1) of subpart A, which applies
to sources covered by subpart N, specifies the manner in which
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records should be kept. In accordance with this provision, files
must be maintained for at least 5 years following each
occurrence, measurement, maintenance, corrective action, report,
or record. The most recent 2 years of data must be retained on
site; the remaining 3 years, however, may be retained off site.
Such files may be maintained on microfilm, computer, floppy disk,
magnetic tape disks, or microfiche.
Comment; Six commenters (IV-D-df, IV-D-03, IV-D-08,
IV-D-19, IV-D-20, IV-D-22) suggested the EPA develop
user-friendly reporting forms to facilitate the reporting
requirements of the rule. One of these commenters (IV-D-08) also
suggested that because the formal rule is difficult to understand
as written, the EPA should produce an easy to follow guidance
document to accompany the rule. Another commenter (IV-D-20)
indicated that the rule (or preamble or Fact Sheet) should
contain a chronological listing of compliance and reporting
requirements that incorporates requirements of both the chromium
electroplating NESHAP and the General Provisions.
Response: The EPA is developing an enabling document to
accompany the rule, and the Small Business Administration is
developing a pamphlet assist small businesses. Both of these
documents are intended to help sources understand the
requirements of the rule and implement the rule.
Comment: One commenter (IV-D-20) requested that the
reporting dates for the initial notification of compliance status
and for the initial performance test referenced in § 63.9(h)(4)
of the proposed General Provisions be revised. Notification of
compliance status is due within 45 days of compliance date,
however the performance test is not due until 120 days after the
compliance date; the emission data gathered during the
performance test will be necessary for submission of compliance
status.
Response: In the General Provisions, the notification of
compliance status is required to be submitted within 60 days
following the completion of the required performance testing, as
is stated in § 63.9(h)(2)(ii), not 60 days from the compliance
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date. Subpart N overrides this requirement to allow sources
additional time to submit the notification of compliance status.
Additional time may be required for the many sources in these
source categories to obtain performance test results. A shorter
timeframe may result in owners or operators having to pay extra
to obtain analytical results within 60 days.
Section 63.347(e)(3) of the final rule requires the notification
of compliance status be submitted 90 days following completion of
the performance test required by § 63.7 of subpart A and
§ 63-343fb) of the final rule if a performance test is required.
The results of performance testing are also due no later than
90 days after completion of the test. Thus, the timeframes are
consistent. If a performance test is not required (e.g., sources
meet the requirements of § 63.343 (b) (2) or (3))/the compliance
status report must be submitted no later than 30 days after the
compliance date.
2•13•4 Requirements of the General Provisions
Comment; One commenter (IV-D-23) requested that the rule
clearly state which sections of the General Provisions apply to
chromium electroplating sources and which do not.
Response: Table 1 has been added to the final rule. This
table identifies which sections of the General Provisions apply
to sources subject to subpart N, and which do not. If a
requirement in the General Provisions is overridden by a
requirement in subpart N, the applicable section in subpart N is
cited.
Comme:nt: Three commenters (IV-D-20, IV-D-28, IV-D-43) noted
that the proposed rule does not contain any requirements for
continuous monitoring systems but subsequently requires a
continuous monitoring system performance report in § 63.347(c).
Two of these commenters (IV-D-20, IV-D-43) asked whether the EPA
intended to refer to section 504(a) of the Act or part 70 of the
General Provisions. One of the three commenters (IV-D-28)
suggested deleting this reference from the rule.
Response; in the General Provisions, continuous monitoring
systems (CMS) are intended to include continuous emission
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monitors, continuous opacity monitors, continuous parameter
monitoring systems, or other manual or automatic monitoring that
is used for demonstrating compliance with an applicable
regulation on a continuous basis. In accordance with this
definition, monitoring of surface tension, foam blanket
thickness, pressure drop, and velocity pressure would be
considered CMS. The EPA recognizes that the term CMS could cause
some confusion among owners or operators of affected sources.
Therefore,.subpart N has overridden the requirements in the
General Provisions that deal with CMS and replaced them with
requirements in subpart N that are more appropriate to these
subcategories. As previously stated, Table 1 specifies which ^
requirements of the General Provisions apply to sources subject
to subpart N, which do not, and which have been overridden by a
specific requirement in subpart N.
Comment: One commenter (IV-D-10) suggested that the initial
notification requirement of section 63.7 of the General
Provisions be waived for sources that hold operating permits with
the State or local agency to reduce reporting burdens for the
sources. In lieu of this requirement, the State or local agency
would submit a list of affected sources to the EPA.
Response; The requirements for the initial notification
that are contained in § 63.347(c) of the final rule are minimal.
The EPA does not think it will be burdensome for sources to
submit this report, especially those sources that hold operating
permits. The information required in the initial notification
has probably been compiled previously by such sources.
Comment; One commenter (IV-D-10) indicated that the
timeframe for review of test plans that is provided in subpart A
of part 63 of the General Provisions is inappropriate and should
be overridden by the chromium electroplating rule.
Response: The final rule overrides the requirement that
sources required to conduct a performance test prepare a
site-specific test plan that meets the requirements of
§ 63.7(b)(l). instead, § 63.344(a) identifies the minimum
elements to be contained in test reports documenting the initial
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performance test, which shall be made available to the
Administrator upon request.
Comment; Given the implications of the General Provisions
for this rule, one^commenter (IV-D-23) statedthat he reserved
the right to submit additional comments on the proposed chromium
electroplating NESHAP following final promulgation of the General
Provisions.
Response; The preamble to the proposed subpart N and the
proposed rule clearly stated that;the General Provisions were
proposed rules at the time, but that sources subject to subpart N
would eventually have to comply with the General Provisions as
promulgated. As such, comments regarding the General Provisions
were to fce made during the comment period for subpart A.
Alternatively, owners or operators of sources affected by
subpart N could have provided comments on the requirements of the
proposed General Provisions during the comment period for
subpart N.
2.14 OPERATING PERMIT PROGRAM
.Comment; Eleven commenters stated that area sources should
not be required to obtain title V operating permits. Four
commenters (IV-D-14, IV-D-23, IV-D-24, IV-D-47) suggested that
the rule should exempt nonmajor sources from title V. One
commenter (IV-D-15) suggested that the NESHAP be written so that
it requires all sources to comply with the emission standards but
does not require title V permits for area sources. Another
commenter (iv-D-10) stated that a title V permit is not necessary
because existing requirements are enforceable through State and
local permits. This commenter and one other (IV-D-43) pointed
out that because area sources are not likely to be subject to
multiple MACT standards or to employ emissions averaging and
complex alternate operating scenarios, title V permits do not
benefit the area sources. This commenter also indicated that
part 70 requires periodic review of the permit, and for area
sources, this review would not result in significant changes from
the original operating permit; periodic review is most useful for
large, complex operations. Two commenters, (IV-D-10, IV-D-22)
::; ' ' 2-148
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said it will be a cost burden for area sources to obtain title V
permits, and the emissions from these sources may be
insignificant (IV-D-22).
Four commenters- (IV-D-10, IV-D-20, IV-D-23, IV-D-43)
suggested that there should be an applicability threshold, or
cut-off, for area sources required to obtain permits. One of
these commenters (IV-D-10) suggested that the threshold be
risk-based. Another of these commenters (IV-D-20) suggested that
the threshold determination for title V permit applicability
could be set at a later date after the EPA has received and
reviewed the initial notifications of compliance status.
Two commenters (IV-D-14, IV-D-47) stated that in preparing^
their title V permit programs, States did not anticipate a need
for emission-unit specific permits at nonmajor sources, and
inclusion of nonmajor sources under title V will require that
many local agencies revise their permit programs. Two other
commenters (IV-D-08, IV-D-10) stated that States will not have
the resources for completing title V permits for area sources;
some states have exempted nonmajor sources from their permitting
programs until the nonmajor source permitting rule is promulgated
in the late 1990's (IV-D-10).
Finally, two commenters (IV-D-40, IV-D-43) asked that a
general permit be included in the final rule to reduce the burden
for small facilities.
Response: The EPA believes that requiring all sources that
are subject to the standards, including area sources, to obtain
title V operating permits is important because of the toxicity of
chromium compounds and the close proximity of many of these
sources to residential areas. The EPA believes that permitting
area sources will not be overly burdensome to permitting
authorities and affected sources for the reasons given below.
First, many States are already permitting these sources
under their State permit programs. The preamble to the final
part 70 rule states that "some nonmajor sources would already be
permitted at the State level, and therefore would have some
experience with the permitting process and completing permit
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applications." Therefore, a State would have little reason to
defer title V permitting of the sources that already have State
operating permits. Second, the burden may be reduced
significantly by issuing general permits to these sources.
According^to the preamble to the final part 70 rule, general
permits «...provide an alternative means for permitting sources
for which the procedures of the normal permitting process would
be overly burdensome, such as area sources under section 112...".
Under this option, States would develop a single general permit
for this source category and issue it to individual sources; or
alternatively, a letter or certification may be used. The burden
would also be reduced by using general permits because public
participation and EPA and affected State review is only necessary
when the initial general permit is drafted and issued. When
subsequent general permits are issued to individual sources,
these activities are not required. Finally, States are
developing small business assistance programs (SBAP's) to assist
these types of sources with the permitting process that will be
funded using the annual fees collected from permitted sources.
Small businesses may also be eligible for reduced permitting
fees. i '. . , . f '' . ,. .
Cgmnjgnt: Three commenters (IV-D-14, IV-D-23, IV-D-47)
suggested that in the event that nonmajor sources are included
under title V permitting, the rule should explicitly state that a
permit isrequired only for applicable emissions units at
nonmajor sources.
Responge; Under title V, sources must include information
on all emission points (except those considered insignificant
under the State or local permit program) in their permit
application. However, applicable emission limitations only need
to be identified for those emission points that are subject to
regulation.
2.15 WORDING OF THE REGULATION
.Comment; Several commenters requested changes or additions
to the definitions of terms provided in section (53.341 of the
regulation. One commenter (IV-D-45) suggested changes regarding
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the definitions of the terms decorative chromium electroplating,
hard chromium electroplating, and stalagmometer. According to
this commenter, the text "...to provide .-a bright surface with
wear and tarnish resistance" for decorative chromium
electroplating and the text "...to provide a surface with wear
resistance, a low coefficient of friction, hardness, and
corrosion resistance" for hard chromium electroplating that are
currently used in the definitions for/these terms limit the
applicability of the regulation; the regulation should apply
regardless of the purpose of the electroplating. Also, this
commenter stated that the term tensiometer should be defined
separately from the term stalagmometer. Two other commenters ^
(IV-D-17, IV-D-58) also suggested changes to the definitions for
the terms hard and decorative chromium electroplating; they
believed that these terms should emphasize the purpose of the
electroplating operation. Decorative electroplating is done
primarily to provide cosmetic effects and hard electroplating is
done primarily to provide functional effects. According to the
commenters, the definition of hard electroplating should also be
written so that the applicability of only one of the listed
functional effects would qualify the electroplating operation as
hard chromium electroplating. These commenters also suggested
that the definition for the term chromium electroplating be
amended to include the electrodeposition of chromium onto
undercoatings, in addition to the electrodeposition of chromium
onto base metals or plastics as the definition currently reads.
Two commenters (IV-D-20, IV-D-43) requested clarification of
the definitions for the terms air pollution control device and
foam blanket and specifically questioned whether foam blankets
are considered to be air pollution control devices according to
the current definitions. In the instance that foam blankets are
an air pollution control device, the final regulation should
clearly identify them as such. Also, in this instance, the
„monitoring, recordkeeping, and reporting requirements for control
devices should apply. However, nonapplicable requirements such
as pressure drop monitoring should be excluded. Another
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commenter (IV-D-24) asked that a definition for the term add-on
air pollution control device be added.
Finally, one commenter (IV-D-41) pointed out that the proper
terminology for referring to chromium electroplating emissions is
"mist emissions," as is used by California and other agencies.
According to this commenter, chromium emissions should not be
referred to as "fumes," as the proposed rule currently is worded.
ResRonse: As mentioned in previous sections of this
document, the definitions for hard chromium electroplating,
decorative chromium electroplating, and chromium anodizing have
been revised. In addition to describing the function of each
type of electroplating and anodizing, the definitions in the
final rule express these electroplating and anodizing operations
in terms of process parameters such as typical electroplating
thickness achieved, current density, and electroplating time.
The term tensiometer has also been added to the list of
definitions. Another new term, "air pollution control
technique," which includes methods such as fume suppressants that
reduce or prevent chromium emissions, has also been added. A
"foam blanket" is a type of fume suppressant and is considered to
be an air pollution control technique. As previously discussed,
the monitoring, reporting, and recordkeeping that applies to
sources controlled with an air pollution control technique has
been clarified in the final rule; requirements are control
technique specific, not source category specific. The term air
pollution control device has been changed to add-on air pollution
control device, and refers to add-on equipment siuch as packed-bed
scrubbers, composite mesh-pad systems, and fiber-bed mist
eliminators. A definition for fiber-bed mist eliminator has been
added in the final rule.
The final rule also contains a definition for fume
suppressant; this definition clarifies that fume suppressants are
considered the same as mist suppressants. It is the EPA's
experience that both terms are used in the industry, and
therefore a definition of fume suppressant was added to eliminate
any confusion.
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Comment; One commenter (IV-G-01) requested that the term
facility in the proposed rule be consistent with the definition
of major source under 40 CFR part 70. Otherwise, large
industrial complexes" that consist of multiple, distinct major
sources under title V are treated as one source under Title III
(of the CAA Amendments). One problem that would arise under the
proposed rule is that maximum cumulative rectifier capacity would
have to be calculated for the entire industrial complex and not
just each major source.
Response: The definition of facility in subpart N is
consistent with the definition of major source in subpart A.
Comment; Four commenters (IV-D-01, IV-D-03, IV-D-40,
IV-D-43) suggested that allowable emission limits, alternative
compliance procedures, compliance dates, monitoring requirements,
recordkeeping requirements, and reporting requirements should be
summarized in table format in the regulation in a manner similar
to the summary tables in the preamble. The table format is
easier to follow than the current written version.
Response: The Agency agrees that providing information in
table format whenever possible in the rule is a convenient method
for summarizing the requirements of the rule. However,
requirements that are written in text format in the rule cannot
be repeated in a table format because of potential
inconsistencies between the text and table. Two tables have been
included in the final rule that present requirements not found
elsewhere in text. Table 1 specifies which requirements of the
General Provisions apply, and Table 2 specifies the work practice
standards. In addition, summary tables of the standards and the
monitoring and reporting requirements are provided in the
preamble.
Comment; Two commenters (IV-D-16 and IV-D-24) indicated
that § 63.345(c) should refer to the O&M plan in
section 63.342(e) rather than section 63.342(d), which refers to
chromium anodizing tanks. Another commenter (IV-D-49) indicated
that § 63.345(c)(3), which refers to the addition of makeup water
for a packed-bed scrubber, is not applicable to the
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composite mesh-pad system that is the subject of section 63.345(c)
One commenter (IV-D-24) suggested that section 63.343, which
references compliance and performance testing, should reference
pressure drop measurement. This commenter also suggested that
the wording of section 63.345(d) be consistent with the wording
of section 63.345 (e).
Response: The commenters are correct in that § 63.345(c) of
the proposed rule should have referred to § 63.342 (e), not
§ 63.342(d). The final rule is organized differently so all
operation and maintenance requirements are included as work
practices in § 63.342(f). Section 63.343 did not reference
pressure drop measurement because, at proposal, pressure drop
measurement was not being conducted for purposes of compliance. *
In the final rule, pressure drop measurement is being done for
purposes of compliance and is required as such in § 63.343(c)(1)
through (4). in a previous response in Section 2.11, the EPA
acknowledged that § 63.345(c) erroneously required the addition
of makeup water to the packed bed for composite mesh-pad systems.
The addition of makeup water to the packed bed is a work practice
standard only for owners or operators of packed-bed scrubbers, as
is clear in § 63.342(f) and Table 2 of the final rule. Finally,
consistent wording is used, as applicable, in the final rule.
gommeilt: One commenter (IV-D-33) requested that the EPA
review the wording of the regulation. The commenter indicated
that the wording of the regulation will cost the company a lot of
money.
lit . ' '•• • .• r
Response: The final version of the regulation differs from
the proposed version. The EPA made changes to clarify
applicability, and compliance, monitoring, recordkeeping, and
reporting requirements. The EPA believes that the final
regulationis clearer, and will be easier for sources to
understandand implement.
.Comment: One commenter (IV-D-21) suggested that the rule
for hard chromium electroplating should clearly indicate that a
source needs to meet the designated emission limit and not a
specified control system design.
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Response; The standards in the rule require a specific
emission limitation (expressed as mg/dscm), and any control
system may be used to meet these standards. Exceptions are the
surface tension limits that are included as standards; surface
tension limits are included for the specific situation in which a
wetting agent-type fume suppressant is used to control chromium
emissions from decorative chromium electroplating or chromium
anodizing tanks. The preamble to the proposed rule described
only those control technologies that the EPA assumed would be
used by industry in meeting the emission limits. The fact that
other control methods were not described in the proposal preamble
does not preclude their use as long as the applicable emission
limit is achieved.
2.16 MISCELLANEOUS
Comment: One commenter suggested that an emissions
averaging scheme be incorporated into the chromium electroplating
NESHAP.
Response; The EPA does not think that there are
opportunities for emissions averaging in this NESHAP. Typically,
there are multiple emission points within a source category, and
emissions averaging allows a source to average across these
various emission points. In the chromium electroplating and
chromium anodizing source categories, there is really only one
emission point, the tank. One might suggest that averaging could
occur by controlling one tank to a level higher than the standard
to compensate for another tank that is controlled to a lesser
degree. However, the EPA does not support leaving a tank
uncontrolled even if another tank at the facility is controlled
to a greater extent.
Comment; One commenter (IV-D-23) noted that the proposed
rule differs significantly from the information that was
presented at the National Air Pollution Control Techniques
Advisory Committee (NAPCTAC) meeting. Specifically, at this
meeting, the EPA stated that area and major sources would be
regulated separately, with different technology requirements
(i.e., MACT v. GACT). Also, according to this commenter, the EPA
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stated that the compliance timeframe would be 3 years after
promulgation for existing sources. At NAPCTAC, composite mesh
pads were the basis of MACT for new hard chromium electroplaters
only, not new and existing. Finally, the trivalent chromium
electroplating process was identified as MACT for new decorative
chromium electroplaters.
Response; The EPA presented the status of the chromium
electroplating and chromium anodizing NESHAP at a briefing for
the NAPCTAC on January 29 through 31, 1991. The purpose of the
if '•!,"• ' • , , , ; | ,'•.,,
NAPCTAC briefing is for the EPA to present the current status of
their regulatory actions to industry, regulatory agencies,
environmental groups, and the public. The information that is
presented at NAPCTAC briefings is subject to chcinge based on
public comments, comments received from the NAPCTAC panel, and
additional information that may be gathered by the EPA in
response to these comments. One of the major changes since
i. 'i ' '' ' • '
NAPCTAC is that composite mesh-pad systems became much more
widely used in the chromium electroplating industry. In the
NAPCTAC briefing, the EPA stated that emerging sidd-on control
technology (e.g., composite mesh pads) were being considered as a
regulatory alternative that was more stringent than the MACT
floor, and that such technologies may become demonstrated during
the rulemaking process. The most recent cost-benefit analysis
conducted by the EPA indicated that these devices are
cost-effective for tanks at existing large, hard chromium
electroplating facilities and all new hard chromium
electroplating facilities. Therefore, they were selected as MACT
for those categories. Regarding the regulation of decorative
chromium electroplating facilities, for the reasons discussed in
Sectipn 2.6.1, the EPA concluded that there was insufficient
information to select the trivalent chromium electroplating
process as new source MACT for decorative chromium electroplating
sources.
During the NAPCTAC briefing, GACT was presented as a
possible alternative for regulating area sources. Regulation of
area sources by GACT was considered for the source categories
:• : ,,,,'2-156.
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covered by this rule, and, for the reasons discussed in
Section 2.4, was not selected. -At the time of the NAPCTAC
briefing, these decisions had not been finalized. Likewise,
section 112(i)(3) of the Act states that the EPA shall establish
a compliance time for existing sources, which provides for
compliance as expeditiously as practicable, but in no event is
later than 3 years after the effective date of the standard. At
the time of the NAPCTAC briefing, this information may have been
presented because the compliance timeframe for the source
categories covered by this NESHAP had not yet been selected.
When the rule was to be proposed, the EPA selected the compliance
dates. For the reasons discussed in Section 2.10, the compliance
date in the final rule is 1 year from the effective date for
existing decorative chromium electroplaters and 2 years from the
effective date for existing hard chromium electroplaters and
chromium anodizers covered by the standard.
Comment: Two commenters (IV-D-52, IV-D-58) suggested that
the EPA educate small businesses on the requirements of this and
other NESHAP through public outreach programs. One commenter
(IV-D-58) pointed out that the provisions of section 507(b)(2)
could be implemented to inform small businesses of the technical
requirements of this rule.
Response: In order to aid small business in the
requirements for stack testing, the EPA has prepared a videotape
on how to build the Method 306A sampling train, how to operate
the train, and how to make and install the enhanced monitoring
equipment. The videotape is entitled "Construction and Operation
of the EPA Method 306A Sampling Train and Practical Suggestions
for Monitoring of Electroplating and Anodizing Facilities," and
will be available in January 1995 for a nominal fee. The
videotape is available through North Carolina State University,
Registrar, Environmental Programs, Box 7513, Raleigh,
NC 27695-7513. The telephone number is (919) 515-4659. The fax
number is (919) 515-4386. In addition, articles on how to make
and operate the testing and enhanced monitoring equipment will be
written and published in trade journals of the industry such as
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the Plating and Surface Finishing and Metal Finishing. Also, as
previously stated, the EPA is developing an Enabling Document and
the Small Business Administration is developing a pamphlet to
help owners or operators understand and implement the rule.
Comment: One commenter (IV-D-19) stated that the EPA should
promulgate the final rule by November 15, 1994 as scheduled.
Response: The final rule will be promulgated by
November 23, 1994 in accordance with a consent decree reached
between the Sierra Club and the EPA.
,„ Ijl1 ' ' ' | , . ' , ,,,",' . , . ;
Comment; One commenter (IV-D-04) questioned whether they
were on the mailing list because they did not receive a copy of
the background information document (BID) for the proposed
standards. Other commenters (IV-D-32, IV-D-34) requested a copy
of an organization's public comments.
Response: Two documents, the BID for the proposed standards
and the New Technology Document, were prepared to identify the
information used in developing the proposed standard. The BID
consists of two volumes, and is too lengthy to distribute to
everyone on the mailing list. The BID and the new technology
document can be obtained from the U. S. EPA Library (MD-35),
Research Triangle Park, North Carolina 27711, telephone number
(919) 541-2777. These documents can also be retrieved from one
Ml ' . . ", ' . ' . .
of the EPA's electronic bulletin boards, the Technology Transfer
Network (TIN). The TTN provides information and technology
exchange in various areas of air pollution control. The service
is free, except for the cost of the phone call. Dial
(919) 541-5742 for up to a 14,400 bps modem. If more information
on TTN is" needed, call the HELP line at (919) 541-5384.
Copies of public comment letters are available for public
inspection and copying between 8:00 a.m. and 5:30 p.m., Monday
through Friday, at the EPA's Air and Radiation Docket and
Information Center^ Waterside Mall, Room 1500, 1st Floor, 401 M
Street, S.W., Washington, DC 20460. The telephone number is
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(202) 260-7548. The fax number is (202) 260-4400. When
requesting information on this standard, refer to Docket
No. A-88-02. Public comment letters are identified according to
the nomenclature in "Table 2-1. A reasonable fee may be charged
for copying.
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TECHNICAL REPORT DATA
(Please read Instructions on reverse before completing)
1. REPORT NO.
EPA 453/R-94-082b
2.
4. TITLE AND SUBTITLE
Chromium Emissions from Chromium Electroplating
and Chromic Acid Anodizing Operations-Background
Information for Promulgated Standards
7. AUTHOR(S)
Lalit Banker, BSD/Organic Chemicals Group
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Emission Standards Division
Office of Air Quality Planning and Standards
U. S. Environmental Protection Agency
Research Triangle Park, NC 27711
12. SPONSORING AGENCY NAME AND ADDRESS
DAA for Air Quality Planning and Standards
Office of Air and Radiation
U. S. Environmental Protection Agency
Research Triangle Park, NC 27711
15. SUPPLEMENTARY NOTES
3. RECIPIENT'S ACCESSION NO.
5. REPORT DATE
November 1994
6. PERFORMING ORGANIZATION CODE
8. PERFORMING ORGANIZATION REPORT NO.
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
13. TYPE OF REPORT AND PERIOD COVERED
Final
14. SPONSORING AGENCY CODE
EPA/200/04
National emission standards to control emissions of chromium compounds from new and existing
chromium electroplating and chromium anodizing tanks are being promulgated under section 112 of the
Clean Air Act. This document summarizes public comments received during proposal and EPA s
responses to these comments. . •
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
Air pollution control
Chromium
Environmental protection
National emission standards
Hazardous air pollutants
Electroplating
Anodizing
18. DISTRIBUTION STATEMENT
Release Unlimited
b. IDENTIFIERS/OPEN ENDED TERMS
Air pollution control
Chromium
Stationary sources
19. SECURITY CLASS (Report)
Unclassified
20. SECURITY CLASS (Page)
Unclassified
c. COSATI Field/Group
21. NO. OF PAGES
170
22. PRICE
EPA Form 2220-1 (Rev. 4-77) PREVIOUS EDITION IS OBSOLETE
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