United States
Environmental Protection
Agency
Office of Air Quality
Planning ana Standards
Research Triangle Park, NC 27711
EPA^53/R-96-006b
July 1996
Air
&EPA
Hazardous Air Pollutant
Emissions from Process
Units in the Elastomer
Manufacturing Industry-
Basis and Purpose Document for
Final Standards, Summary of Public
Comments and Responses
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EPA-453/R-96-006b
'; Hazardous Air Pollutant Emissions
», •
^~ From Process Units in the
V,
K4 Elastomers Manufacturing Industry—
Basis and Purpose Document for
Final Standards, Summary of
Public Comments and Responses
-j
Emission Standards Division
U.S. Environmental Protection Agency
Office of Air and Radiation
Office of Air Quality Planning and Standards
Research Triangle Park, North Carolina 27711
July 1996
U.S. Environmental Protection Agency
Region 5, Library (PL-12J)
77 West Jack&on Boulevard, 12th Floor
Chicago, IL 60604-3590
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DISCLAIMER
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.
11
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ENVIRONMENTAL PROTECTION AGENCY
Hazardous Air Pollutant Emissions from Process Units in the
Elastomers Manufacturing Industry -- Basis and Purpose
Background Information for Final Standards
1. The standards regulate organic hazardous air pollutant
(HAP) emissions from the production of butyl rubber
(including halobutyl rubber), epichlorohydrin
elastomers, ethylene propylene rubber, Hypalon™,
neoprene, nitrile butadiene rubber (including nitrile
butadiene latex), polybutadiene rubber (including
polybutadiene latex), polysulfide rubber, and styrene
butadiene rubber (including styrene butadiene latex).
Only those elastomer product process units that are
part of major sources under section 112(d) of the Clean
Air Act (Act) will be regulated.
2. For additional information contact:
Mr. Robert Rosensteel
Organic Chemicals Group
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
Telephone: (919) 541-5608
3. Paper copies of this document may obtained from:
U.S. Environmental Protection Agency Library (MD-36)
Research Triangle Park, NC 27711
Telephone: (919) 541-2777
National Technical Information Service (NTIS)
5285 Port Royal Road
Springfield, VA 22161
Telephone: (703) 487-4650
4. Electronic copies of this document may be obtained from
the EPA Technology Transfer Network (TTN). The TTN is
an electronic bulletin board system which is free,
except for the normal long distance charges. To access
the Basis and Purpose Document:
Set software communication setting to 8 bits,
no parity, and 1 stop bit
Set a terminal emulation of either VT100,
VT102, or ANSI
Baud rates of 1200, 2400, 9600, and 14,400
are accepted
111
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Use access number (919) 541-5742; access
problems should be directed to the system
operator at (919) 541-5384
Register online by providing a personal name,
password, and company name, address, and
phone number
Specify TTN Bulletin Board: CAAA (Clean Air
Act Amendments)
Select menu item: Title III: Hazardous Mr
Poll.
Select menu item: Policy Guidance Documents
To download, type filename: [Insert Filename
once it is provided by TTN person]
IV
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TABLE OF CONTENTS
Page
1.0 SUMMARY 1-1
1.1 INTRODUCTION 1-1
1.2 SIGNIFICANT COMMENTS AND CHANGES SINCE
PROPOSAL 1-5
1.2.1 Applicability Provisions and
Definitions 1-6
1.2.2 Storage Vessel Provisions 1-10
1.2.3 Continuous Front-end Process Vent
Provisions 1-14
1.2.4 Batch Front-end Process Vent
Provisions 1-17
1.2.5 Back-end Process Operation Provisions 1-21
1.2.6 Wastewater Operations Provisions . . . 1-30
1.2.7 Equipment Leak Provisions 1-32
1.2.8 Emissions Averaging Provisions .... 1-33
1.2.9 Monitoring 1-33
1.2.10 Recordkeeping and Reporting 1-34
2.0 APPLICABILITY 2-1
2.1 SELECTION OF SOURCE CATEGORY 2-1
2.1.1 Elastomer Production Definitions . . . 2-1
2.1.2 Other Processes 2-2
2.2 SELECTION OF POLLUTANTS 2-9
2.3 SELECTION OF AFFECTED SOURCE 2-10
2.3.1 Major Source Criteria 2-10
2.3.2 Use of Organic HAP 2-12
2.3.3 Definition of Affected Source and
Elastomer Product Process Unit (EPPU) . 2-15
2.4 MODIFICATION AND RECONSTRUCTION 2-23
2.5 IMPACTS 2-25
2.6 DEFINITIONS 2-27
2.7 MISCELLANEOUS 2-30
2.7.1 Storage Vessel Assignment to EPPU . . 2-30
2.7.2 Relationship to Other Rules 2-31
2.7.3 General 2-33
3.0 STORAGE VESSELS 3-1
3.1 APPLICABILITY REQUIREMENTS 3-2
3.2 SELECTION OF EMISSION LIMITS 3-6
3.3 ASSOCIATED DEFINITIONS 3-9
3.4 MISCELLANEOUS 3-10
4.0 CONTINUOUS FRONT-END PROCESS VENTS 4-1
4.1 APPLICABILITY REQUIREMENTS 4-1
4.2 SELECTION OF EMISSION LIMITS 4-3
5.0 BATCH FRONT-END PROCESS VENTS 5-1
5.1 BASIS FOR THE STANDARD 5-1
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TABLE OF CONTENTS
(continued)
Page
5.2 APPLICABILITY REQUIREMENTS 5-3
5.2.1 Group Determination 5-3
5.2.2 Other Applicability Issues 5-8
5.3 EMISSION LIMITS 5-9
5.4 TEST METHODS AND MONITORING 5-11
5.5 ASSOCIATED DEFINITIONS 5-14
5.6 MISCELLANEOUS 5-15
6.0 BACK-END PROCESS OPERATIONS 6-1
6.1 APPLICABILITY REQUIREMENTS 6-1
6.2 EMISSION LIMITS 6-3
6.2.1 Averaging Period 6-3
6.2.2 Residual Organic HAP Limitations . . . 6-3
6.2.3 Compliance Using Stripping Technology 6-16
6.2.4 Compliance Using Control or Recovery
Devices 6-24
6.3 TEST METHODS AND MONITORING 6-27
6.3.1 Residual Organic HAP Tests 6-27
6.3.2 Control or Recovery Device Testing . . 6-29
6.4 REPORTING AND RECORDKEEPING 6-30
6.5 ASSOCIATED DEFINITIONS 6-31
6.6 CARBON DISULFIDE LIMITATIONS ' . . . 6-35
7.0 WASTEWATER OPERATIONS 7-1
7.1 BASIS FOR THE STANDARDS 7-1
7.2 APPLICABILITY REQUIREMENTS 7-2
7.3 SELECTION OF EMISSION LIMITS 7-5
8.0 EQUIPMENT LEAKS 8-1
8.1 APPLICABILITY REQUIREMENTS 8-1
8.2 COMPLIANCE DATES 8-2
8.3 ASSOCIATED DEFINITIONS 8-3
9.0 EMISSIONS AVERAGING 9-1
10.0 PERFORMANCE TESTING 10-1
11.0 MONITORING 11-1
12.0 RECORDKEEPING AND REPORTING 12-1
va.
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ACRONYM AND ABBREVIATION LIST
ACRONYM
ABS
ACT
ASTM
BR
CAAA
CAS
CBI
CEM
CFR
COD
CTG
DOD
EPI
EPPU
EPR
FR
HAP
HER
HON
HYP
IISRP
LDAR
MACT
NBL
NBR
NEO
NESHAP
NSPS
PBR/SBRS
pH
PSR
RACT
RCRA
RCT
SBL
SBRE
SID
SOCMI
SPI
SSM
SSP
TOC
TRE
TRI
TERM
acrylonitrile butadiene styrene
Alternative Control Technology
American Society for Testing Materials
butyl rubber
Clean Air Act Amendments
Chemical Abstracts Service
confidential business information
continuous emissions monitoring
Code of Federal Regulations
chemical oxygen demand
Control Technology Guidance
Department of Defense
epichlorohydrin rubber
elastomer product process unit
ethylene-propylene rubber
FEDERAL REGISTER
hazardous air pollutant
halobutyl rubber
hazardous organic NESHAP
Hypalon™
International Institute of Synthetic
Rubber Producers
leak detection and repair
maximum achievable control technology
nitrile butadiene latex
nitrile butadiene rubber
neoprene
national emission standards for
hazardous air pollutants
new source performance standards
polybutadiene rubber and styrene
butadiene rubber by solution
hydrogen-ion concentration
polysulfide rubber
reasonably available control technology
Resource Conservation and Recovery Act
reference control technology
styrene butadiene latex
styrene butadiene rubber by emulsion
supplementary information document
synthetic organic chemical manufacturing
industry
Society of the Plastics Industry, Inc.
startup, shutdown, and malfunction
solid state polymerization
total organic compound
total resource effectiveness
Toxic Release Inventory
Vll
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ACRONYM
ACRONYM AND ABBREVIATION LIST
(Continued)
TERM
TRIS
TTN
VOC
VOHAP
WTU
ABBREVIATION
BtU/hr
°C
cfm
oF
gpm
kg/yr
kPa
iranHg
ppm
ppmv
ppmw
psia
tons/yr
Toxic Release Inventory System
Technology Transfer Network
volatile organic compound
volatile organic hazardous air
pollutant
wastewater treatment unit
UNIT OF MEASURE
British thermal units per hour
degrees Celsius
cubic feet per minute
degrees Fahrenheit
gallons per minute
kilograms per year
kilopascals
millimeters of mercury
parts per million
parts per million by volume
parts per million by weight
pounds per square inch, absolute
tons per year
Vlll
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1.0 SUMMARY
1.1 INTRODUCTION
On June 12, 1995, the U.S. EPA proposed a NESHAP for
HAP emissions from the production of butyl rubber (including
halobutyl rubber), epichlorohydrin elastomers, ethylene
propylene rubber, Hypalon™, neoprene, nitrile butadiene
rubber (including nitrile butadiene latex), polybutadiene
rubber (including polybutadiene latex), polysulfide rubber,
and styrene butadiene rubber (including styrene butadiene
latex) under Section 112(d) of the Act. These nine polymer
types are generally referred to as "elastomers." Due to the
similarities in these polymers and the processes used to
produce them, the EPA studied and regulated them together,
under the title "Polymers and Resins I." Throughout this
document the terms "elastomers" and "Polymers and Resins I"
will be used to collectively refer to the polymer types
listed above.
Public comments were requested on the proposed standard
and comment letters were received from industry
representatives and governmental entities. A total of 29
comment letters were received. Table l-l presents a listing
of all persons submitting written comments, their
affiliation, and their docket item number. A public hearing
was not requested.
The written comments that were submitted on the
proposed rule have been summarized and responses to the
comments are included in the following sections. This
summary of comments and responses serves as the basis
1-1
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TABLE 1-1.
LIST OF COMMENTERS ON PROPOSED NATIONAL EMISSION
STANDARDS FOR HAZARDOUS AIR POLLUTANTS
Air Docket A-92-
44
Item Number
Commenter and affiliation
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
Roger D. Randolph, State of Missouri
Department of Natural Resources
Division of Environmental Quality
Frank Kennedy
American Synthetic Rubber Corporation
Jennifer Keane
Baker & Botts, L.L.P.
[on behalf of Firestone Synthetic
Rubber & Latex Company]
Thomas R. Herman, P.E.
Zeon Chemicals Incorporated
D.G. Berkebile
The Goodyear Tire & Rubber Company
D.G. Berkebile
The Goodyear Tire & Rubber Company
Dale L. McKinnon
Manufacturers of Emission Controls
Association
Robert J. Fensterheim
Styrene Butadiene Latex Manufacturers
Council, Incorporated
Michael J. Wax
Institute of Clean Air Companies
Gary E. Marchant
Kirkland & Ellis
[on behalf of the International
Institute of Synthetic Rubber
Producers, incorporated]
Lloyd J. Tabary II, Esq.
DSM Copolymer
Lloyd J. Tabary II, Esq.
DSM Copolymer
Lloyd J. Tabary II, Esq.
DSM Copolymer
1-2
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TABLE 1-1.
LIST OF COMMENTERS ON PROPOSED NATIONAL EMISSION
STANDARDS FOR HAZARDOUS AIR POLLUTANTS
Air Docket A-92-
44
Item Number
Commenter and affiliation
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
Matthew 0. Tanzer/Bernadine D. Flood
General Electric Plastics
Ajay Gupta
Hampshire Chemical Corporation
Reginaldo A. Montague
Uniroyal Chemical Company,
Incorporated
Brian L. Taranto
Exxon Chemical Americas
David W Gustafson/Toby A. Threet
Env. Health & Regulatory Affairs
Legal Department
Dow Chemical Company
J.F. Finn
Continental General Tire, Incorporated
J.C. Moorad
Shell Chemical Company
J.C. Hovious
Union Carbide Corporation
B.J. Price
Phillips Petroleum Company
Jeffrey A. Saitas
Texas Natural Resource Conservation
Commission
Charles W. Keffer, Jr.
Monsanto Company
R.H. Colby, D.F. Theiler
State and Territorial Air Pollution
Program Administration/Association of
Local Air Pollution Control Officers
John A Dege Jr.
DuPont SHE Excellence Center
Frank Kennedy
American Synthetic Rubber Corporation
1-3
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TABLE 1-1. LIST OF COMMENTERS ON PROPOSED NATIONAL EMISSION
STANDARDS FOR HAZARDOUS AIR POLLUTANTS
Air Docket A-92- Cotnmenter and affiliation
44
Item Number
IV-G-18 Jennifer Keane
Baker & Botts, L.L.P.
[on behalf of Firestone Synthetic
Rubber & Latex Company]
IV-G-2a William 0'Sullivan
State of New Jersey Department of
Environmental Protection
a Other items found in category IV-G of the docket are not addressed as
they are primarily either follow-up correspondence related to the
original public comment letters and the issues contained therein, or are
follow-up correspondence related to meetings held with industry in order
to discuss those issues.
1-4
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for revisions made to the NESHAP between proposal and
promulgation.
1.2 SIGNIFICANT COMMENTS AND CHANGES SINCE PROPOSAL
In response to comments received on the proposed
standards, several changes have been made to the final rule.
While several of these changes are clarifications designed
to make the EPA's intent clearer, a number of them are
significant changes to the requirements of the proposed
standards. A summary of the substantive comments and/or
changes made since the proposal are described in the
following sections. Additional information on the final
rule is contained in the docket for this rule (Docket
A-92-44) .
National Emission Standards for Hazardous Air Pollutant
Emissions from the Production of Acrylonitrile Butadiene
Styrene (ABS) Resin, Styrene Acrylonitrile (SAN) Resin,
Methyl Methacrylate Acrylonitrile Butadiene Styrene (MASS)
Resin, Methyl Methacrylate Butadiene Styrene (MBS) Resin,
Polystyrene Resin, Poly(ethylene terephthalate) (PET) Resin,
and Nitrile Resin (Group IV Polymers and Resins) (40 CFR 63,
subpart V), were developed concurrently with subpart U.
Many of the basic requirements of the two rules are alike,
and in some cases they are identical. Subpart V was
proposed on March 29, 1995, and comments from the public
were received. In many instances, similar comments were
received on analogous sections of subparts U and V. In
these instances, the project teams on the two standards
worked together to address the comments and make appropriate
rule changes. However, in some instances, comments were
received on subpart V, and not on subpart U, that were
applicable to provisions of subpart U. A summary of these
1-5
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comments can be found in the "Hazardous Air Pollutant
Emissions from Process Units in the Thermoplastics
Manufacturing Industry-- Basis and Purpose Document for
Final Standards, Summary of Public Comments and Responses,"
(EPA-453/R-96-001b, May 1996; Docket Number A-92-45, Item
Number V-C-1). In a few cases, the EPA decided that a
change to subpart U based on these comments was appropriate.
These changes did not result in a change in the stringency
of the subpart U provisions, but were typically changes to
improve the clarity of the rule. The one area where a
subpart V comment resulted in a tangible change to subpart U
was in the batch vent applicability determination, as an
affected source is allowed to determine the group status of
a batch front-end process vent based on its primary product.
1.2.1 Applicability Provisions and Definitions
1.2.1.1 Designation of Affected Source and the Definition
of Elastomer Product Process Unit
Commenters expressed confusion about the definitions of
"affected source" and "elastomer product process unit"
(EPPU) in the proposed rule. The EPA reviewed both
definitions and agreed the definitions needed clarification.
In response, the EPA has revised the language describing
affected source and EPPU in the final rule.
In the final rule, the existing affected source is
defined as each group of one or more EPPUs that manufacture
the same elastomer product as their primary product, and (1)
1-6
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are located at a major source plant site, (2) are not
exempt, and (3) are not part of a new affected source. This
means that each plant site will have only one existing
affected source in any given subcategory.
If a plant site with an existing affected source
producing elastomer A as its primary product constructs a
new EPPU also producing elastomer A as it primary product,
the new EPPU is a new affected source if the new EPPU has
the potential to emit more than 10 tons per year of a single
HAP, or 25 tons per year of all HAP. In this situation, the
plant site would have an existing affected source producing
elastomer A, and a new affected source producing
elastomer A. Each subsequent new EPPU with potential HAP
emissions above the levels cited above would be a separate
new affected source.
New affected sources are also created when an EPPU is
constructed at a major source plant site where the elastomer
product was not previously produced, with no regard to the
potential HAP emissions from the EPPU. Another instance
where a new affected source is created is if a new EPPU is
constructed at a new plant site (i.e., green field site)
that will be a major source. The final manner in which a
new affected source is created is when an existing affected
source undergoes reconstruction, thus making the previously
existing source subject to new source standards. This
1-7
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approach to defining new affected source was selected in
order to make subpart U more consistent with the HON.
The definition of EPPU was revised to include a list of
the collection of equipment that comprises an EPPU. Because
wastewater operations are ancillary equipment and are often
used by more than one EPPU and may be used by more than one
affected source, they are not included as part of the EPPU.
1.2.1.2 Definition of Organic HAP
Numerous commenters recommended that the EPA restrict
the list of organic HAP in the final rule to those that are
used or are present in significant quantities at EPPUs or
those that are listed in the HON, subpart F, table 2. The
EPA agreed with the commenters that a table providing a
listing of the specific organic HAP to be regulated for each
subcategory covered by the rule should be included in the
final rule. Therefore, the definition of organic HAP was
revised to specify those organic HAP known to be used or
present in significant quantities for each subcategory. This
list is provided in table 7 of the final rule.
This revised definition was developed using available
process description information received from industry and
gathered from available literature. Because there may be
additional organic HAP present at an affected source, the
final rule requires owners or operators to notify the EPA of
the presence of any additional organic HAP based on the
following criteria: (l) organic HAP is knowingly introduced
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into the manufacturing process, or has been or will be
reported under any Federal or State program, such as TRIS or
Title V; and (2) the organic HAP is presented in Table 2 of
subpart F.
1.2.1.3 Determining- New Source Status
The EPA received comments regarding the process for
determining if new or existing source requirements would
apply to a particular EPPU. In response to those comments,
the EPA has revised the provisions in the final standards.
Under the final standards, a newly constructed EPPU that
manufactures an elastomer product previously produced at the
plant site must also have the potential to emit major
quantities (10 tons per year of any HAP or 25 tons per year
of any combination of HAP) in order to be subject to new
source requirements. A newly constructed EPPU that
manufactures an elastomer product not previously produced at
the plant site is considered a new affected source and is
subject to new source requirements regardless of whether the
new EPPU has the potential to emit major quantities of HAP
or not.
This approach to defining a new affected source was
selected in order to make subpart U more consistent with the
HON. This standard differs from the HON, however, in that
it applies to multiple source categories. Thus, unlike the
HON, a newly added EPPU at a facility is covered by this
rule even if that EPPU is in a different source category
1-9
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form the existing EPPUs at the facility. It is the EPA's
position that the addition of a process unit in a different
source category is a new source and must meet the
requirements for new sources even though the EPPU may have
the potential to emit less than 10 tons per year of a single
HAP or 25 tons per year of all HAP. Indeed, if a source
covered by another MACT standard (i.e., a different source
category) were built at a HON facility, that source would be
subject to the new source requirements under that MACT
standard.
1.2.1.4 Flexible Operation Units
The final rule has retained the HON concept of flexible
operation units, but the language in the final rule has been
significantly modified to more adequately address polymer
production facilities. The final provisions require
flexible operation units with an elastomer as the primary
product to commit to complying with the elastomers rule at
all times, regardless of what product they are producing at
any particular time. The primary product for a flexible
operation unit is determined based on projected production
for the next 5 years.
1.2.2 Storage Vessel Provisions
As discussed in more detail in Section 3.0 of this
document, in comments received on the storage tank
provisions the EPA noted a common misinterpretation of the
proposed regulation related to the distinction between a
1-10
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"storage vessel" and a "surge control vessel". The EPA
determined that many of the comments received on "storage
vessels" were in fact referring to vessels that fall under
the definition of surge control vessel. The EPA suggests
that owners and operators of facilities subject to subpart U
pay careful attention to these definitions.
1.2.2.1 Applicability requirements
Several comments were received requesting that the EPA
consider the exemption of vessels storing specific HAP or
products. In fact, one commenter indicated that the EPA
should conduct a full floor analysis for new and existing
storage vessels, considering each chemical separately and
the various sizes of tanks for each subcategory. Other
commenters supported the exemption of stripped latex storage
tanks from control requirements, but also declared that high
conversion SBR or polybutadiene latex storage tanks should
also be exempt. Another commenter stated that tanks
downstream of EPR stripping operations should be exempt from
storage vessel requirements, just as those containing latex
downstream of stripping operations are exempt.
The EPA does not believe that the floor analyses for
each HAP stored at elastomer production facilities are
required to be conducted under the Clean Air Act (Act), nor
should they be conducted. The Act requires the EPA to set
emission standards for HAP on a source category (or
subcategory) basis,- it does not compel the EPA to establish
1-11
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separate control measures for each HAP emitted by a source
in the category. As suggested by the commenter, this
approach could result in an incomplete standard, since it
would not include a standard for a listed HAP that may be
used in the future by elastomer facilities.
Further, consideration of individual HAP storage vessel
controls would not be representative of facility-wide
storage vessel control levels.
However, the EPA believes that it is reasonable to
exempt a storage vessel from the final regulation when it is
clear that the vessel would never be a Group 1 storage
vessel. The EPA determined that the following HAP used in
the elastomer industry have low enough vapor pressures that
vessels storing these HAP would never be included in
Group 1: acrylamide, epichlorohydrin, and styrene.
Therefore, the final rule exempts storage vessels containing
these HAP at existing sources. This exemption is also
extended to surge control vessels and bottoms receivers at
existing sources.
In addition, the EPA is convinced that a SBL storage
vessel (high conversion or otherwise) would never contain
sufficient HAP to exceed the vapor pressure cutoff for
Group 1 storage vessels. This is primarily due to the low
vapor pressure of styrene. Therefore, the final rule
exempts all SBL storage vessels, surge control vessels, and
1-12
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bottoms receivers from the requirements of sections 63.484
and 63.502.
Finally, the EPA agrees that storage vessels, surge
control vessels, and bottoms receivers downstream of
stripping operations at ethylene-propylene rubber facilities
that are in compliance with the provisions of section 63.494
[old section 63.487-1] of the final rule through the use of
stripping technology should be exempt from the storage
vessel, surge control vessel, and bottoms receiver
requirements. Further, the EPA believes that these
exemptions should also extend to the other subcategories
required to comply with the residual organic HAP limitations
in section 63.494 [old section 63.487-1] (a)(l)-(3).
However, since the residual organic HAP content of rubber
leaving the stripping operations at ethylene propylene
rubber and polybutadiene/ styrene-butadiene rubber by
solution facilities complying with these provisions through
the use of add-on control is not restricted, these
exemptions are not available to these facilities.
1.2.2.2 Emission limits
Commenters requested that the regulation allow the use
of alternative storage vessel/surge control vessel control
techniques. Two commenters described specific control
systems present at their facilities, and asked that the EPA
include allowances for these systems in the rule. They
stressed that such allowances should consider the overall
1-13
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effectiveness of the control system, and not just the
efficiency of the control or recovery device.
The EPA agrees that it is reasonable to consider the
overall effectiveness of a control "system" in determining
compliance with the rule, and that such systems that have
been demonstrated to be equivalent to the reference control
technology should be allowed. While the EPA believes the
system described by the commenter could be demonstrated to
be equivalent to the reference control technology for surge
control vessels, the commenter did not provide sufficient
documentation to allow a complete evaluation of equivalence.
However, the EPA maintains that subpart U, as proposed,
already provides the opportunity for the commenter, as well
as other elastomer production facilities, to demonstrate
equivalency of alternative control techniques. For storage
vessels, section 63.121 of subpart G addresses the
procedures to obtain approval of alternative means of
emission limitations. For surge control vessels and bottoms
receivers, these procedures are contained in section 63.177
of subpart H. In summary, these sections specify that the
owner or operator must submit documentation of the
equivalency determination to the Administrator.
1.2.3 Continuous Front-end Process Vent Provisions
1.2.3.1 Applicability requirements
Several commenters stated that the exemption from
halide controls for butyl/halobutyl production should be
1-14
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extended to all rubber manufacturers, since halogen-
containing compounds or by-products have historically been
routed to flares. Another commenter agreed with the
exemptions for butyl and halobutyl production facilities,
but pointed out that this exemption should only be
applicable to existing sources.
Only one existing facility was identified in each the
halobutyl and the butyl rubber subcategories. At both of
these facilities, halogenated vent streams were vented to a
flare and/or boiler. Since both of these subcategories were
single-facility subcategories, the MACT floor was determined
to be the existing level of control. The EPA examined the
impacts of requiring halogenated vent streams at the
halobutyl and butyl rubber facilities to comply with the
proposed requirements for all other elastomer subcategories
(i.e, the HON-level of control). The EPA concluded that the
costs associated with this level of control were not
reasonable, given the associated emission reduction.
Therefore, the proposed regulation allowed halogenated
streams at halobutyl and butyl rubber facilities that were
routed to a flare or boiler prior to proposal to continue to
be controlled with these combustion devices, without
additional control for the resulting halides.
Prior to proposal, the EPA was aware of one EPR
facility that also routed a halogenated vent stream to a
boiler. However, since only one of five EPR facilities
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reported this situation, the EPA concluded that this level
of control was not the MACT floor for EPR. Other EPR
producers claimed that they also had halogenated streams at
their facilities, but none offered any information to
quantify the amount of halogens in the stream to determine
if the streams could be classified as halogenated.
After proposal, the EPA learned that the chlorinated
organic compounds are present in streams at all of the EPR
facilities. These compounds are a by-product of the
polymerization reaction, resulting from a chlorinated
catalyst. At all four of the facilities contacted, the
streams containing the chlorinated compounds are routed to
either a flare or boiler. Due to the widely varying
concentration in the stream, all facilities indicated that
it was difficult, if not impossible, to accurately determine
the halogen atom concentration in the vent stream. However,
all expressed confidence that at times, the halide threshold
in the incoming stream was exceeded.
Therefore, the EPA concluded that four of the five EPR
facilities have halogenated streams that are routed to
either a boiler or flare. For this reason, the EPA
determined that the floor for EPR is the existing level of
control for these halogenated vent streams. In addition, as
with halobutyl and butyl rubber, the EPA does not believe
that it would be cost-effective to require new incinerators
and scrubbers to be installed at these facilities, when the
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only net emission reduction would be the reduction of the
hydrochloric acid, since the reduction of the halogenated
organic compound in the incinerator would be the same as was
already being achieved in the boiler or flare. However, as
noted above, sufficient stream-specific information was not
available to conduct this analysis. Therefore, the final
rule has been changed to extend the exemption for existing
halogenated streams routed to a boiler or flare to EPR
producers. Further, the final rule specifies that this
exemption does not apply to new sources.
1.2.3.1 Emission Limits
Based on a commenter's request, the final rule exempts
a vent stream routed to an internal combustion engine as
primary fuel from source testing requirements. The final
rule also requires that the on/off status of internal
combustion be monitored as a means of demonstrating
compliance with these control requirements.
1.2.4 Batch Front-end Process Vent Provisions
Commenters believed that batch front-end process vent
provisions were inappropriate and unnecessarily burdensome.
Several commenters disagreed with the EPA's reliance on the
Batch Processes ACT document in the development of the batch
vent provisions, claiming that it was not appropriate to the
elastomer manufacturing industry.
The EPA believes that the potential for HAP emissions
from batch operations at elastomer production facilities
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warrant control. While the EPA disagrees with the statement
that the provisions are inappropriate, the EPA certainly
appreciates comments regarding the complexity of the
proposed batch vent provisions. In the final rule, these
provisions have been simplified. Many of these changes are
discussed below.
1.2.3.1 Applicability requirements
In response to comments on the batch front-end process
vent applicability provisions, the volatility class concept
has been eliminated. The Batch Processes ACT developed an
annual threshold emission level for each of three volatility
classes. The EPA initially judged that selection of a
single annual threshold emission level would not be
appropriate and included all three levels in the proposed
standards. However, upon further review, the EPA found no
adverse impact would result from the use of a single annual
threshold emission level and, therefore, the final standards
have been significantly simplified. Besides removing the
requirement to determine the volatility class, the final
standards contain only one equation for determining the
cutoff flow rate [new section 63.488(f)], which is the last
step in the group determination process.
A commenter on the proposed Polymers and Resins IV (40
CFR 62, subpart V) regulation suggested changing the batch
vent group determination provisions to only utilize
emissions data from an EPPU' s primary product. The EPA
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agreed that to base the group determination on a single
product could, if appropriately applied, provide acceptable
results from an environmental perspective, while simplifying
the compliance requirements for and improving the
enforceability of the batch front-end process vent
standards. Therefore, the final standards contain
provisions allowing the owner or operator of an affected
source to perform the group determination for batch front-
end process vents based on annualized production of a single
batch product. However, the EPA does not consider it to be
appropriate from an environmental perspective to allow
anything other than the worst-case HAP emitting batch
product to be considered when basing applicability on a
single product. Therefore, the final standards specify that
the worst-case HAP emitting batch product be used when an
owner or operator chooses to annualize a single product for
purposes of determining applicability. The final standards
define the worst-case HAP emitting product and describe how
emissions are to be annualized to represent full-time
production, where full-time production does not necessarily
mean operating at maximum production rate. Since the
proposed batch vent provisions were similar between subpart
U and V, the EPA decided that this change was also
appropriate for this final regulation, subpart U.
Several commenters stated that the proposed provisions
for the methods allowed for the calculation of batch front-
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end process vent emissions were overly restrictive. The
proposed rule required that emissions be calculated using
either the emission estimation equations or source testing.
If the owner or operator could demonstrate that both the
equations and source testing were inappropriate, then they
were allowed to use engineering assessment to calculate HAP
emissions. The commenters believed that an affected source
should be allowed to use engineering assessments without
having to demonstrate that source testing was inappropriate.
The EPA maintains that it is imperative that a
consistent technique for the estimation of batch front-end
process vent emissions be used, which is provided through
the emission estimation equations. The EPA believes the
data required to use the batch front-end process vent
emissions estimation equations should be obtainable with
reasonable effort. The final standards continue to require
use of the emissions estimation equations, unless the owner
or operator can demonstrate that these equations are
inappropriate.
However, the EPA has concluded that direct measurement
of emissions through testing may prove to be difficult and
may or may not provide an increased assurance of accuracy
over the use of engineering assessment. Therefore, if an
owner or operator can demonstrate that the emissions
estimation equations are not appropriate, the final
standards allow the selection of either direct measurement
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or engineering assessment. Further, criteria for
demonstrating that the emissions estimation equations are
not appropriate to a specific batch emissions episode have
been added to the final standards. These criteria require
either: 1) the availability of test data that demonstrate a
greater than 20 percent discrepancy between the test value
and the estimated value, or 2) that the owner or operator
demonstrate to the Administrator that the emissions
estimation equations are not appropriate for a given batch
emissions episode.
1-2.5 Back-end Process Operation Provisions
The back-end process operation provisions received the
majority of the comments on the proposed rule. Significant
comments were received on practically every aspect of these
provisions. Following is a summary of the comments that
resulted in notable changes to the back-end process
operation requirements.
1.2.5,1 Averaging period
Several commenters declared that compliance based on a
weekly average HAP limitation was unreasonable, and that
compliance should be demonstrated on the basis of a monthly
(or 30-day) rolling average instead. These commenters
claimed that requiring compliance based on a weekly average
fails to provide adequate operational flexibility for
manufacturers to produce different grades of polymers in
accordance with customer demands.
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Upon investigation of this issue, the EPA concluded
that a monthly averaging period for the residual HAP
limitations was more appropriate, and the final rule has
been revised to reflect this change. Changing to a monthly
averaging period will provide more operational flexibility
to elastomer producers, while maintaining the same annual
emission reduction.
1.2.5.2 Residual organic HAP limitations
Commenters objected to numerous aspects of the residual
organic HAP limitations. Most of these comments were
directed towards the methods used to determine the back-end
MACS floors. Discussed below are comments on definitions,
test methods, and other areas that affect the determination
of the residual organic HAP limitations. The EPA addressed
these comments and re-assessed the MACT floors.
Definition of crumb rubber dry weight. Comments stated
that, for solution processes, the definition of "crumb
rubber dry weight" should not exclude extender oils and
carbon black for compliance purposes, because these are an
integral part of the polymer. The EPA agrees with these
comments, and revised the definition of crumb rubber dry
weight to reflect this opinion.
Residual organic HAP test methods: Concurrent with the
proposal of subpart U, the EPA proposed three residual HAP
test methods - one each for SBRE, PBR/SBRS, and EPR.
Several commenters stated that no single analytical method
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will produce consistent results for all polymers, and
consequently, each company should be allowed to demonstrate
compliance using a company-specific method that is
comparable to the EPA test method.
The EPA agrees with the commenters and has undergone an
extensive effort to accommodate their request. The EPA
concluded that it was appropriate to allow every interested
company to validate their own test method using a modified
version of 40 CFR 63, Appendix A, Method 301.
A total of nine test methods were submitted (three for
EPR, three for SBRE, and three for PBR/SBRS). Upon review
of the methods and validation data, the EPA approved all
nine methods. Therefore, there will be nine accepted
residual HAP methods that will be referenced in section
63.495 [old section 63.487-2] (e) of the final rule.
MACT floor determination. Commenters indicated that
the selection of a MACT floor "somewhere between the mean,
median, and mode" did not represent central tendency. They
maintained that a mean is the correct approach for
establishing the MACT floor. The EPA agreed that one
measure of central tendency should be used, and decided that
the mean was the most appropriate measure for the residual
organic HAP limitations floor determinations. In some
situations, the use of the mean can result in a floor level
of control that is not represented by any available control
technology. However, this did not apply to this situation.
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where the emissions used to determine the floor were a
result of process-specific stripping techniques, and not
specific add-on control technologies.
For EPR and PBR/SBRS, cotranenters stated that combining
data received from different companies using different
sampling and analytical methods, without establishing
whether the methods achieve comparable results, was not an
appropriate way to establish residual HAP limits. The
cotranenters stated that if production figures and dryer stack
testing results were used to establish these limits, these
results cannot be equated to those from crumb sampling at
the EPA's designated sampling point, because there are
numerous potential emission sources between the proposed
sampling point and the stack testing locations. In
addition, commenters indicated that the proposed limitation
did not recognize the fact that residual HAP may remain in
the polymer after finishing. Finally, the commenters also
said that using annual emissions and limited weekly data to
establish weekly limits is inherently uncertain, and may
have resulted in an inappropriate standard.
In the original MACT floor analyses, the EPA presumed
that the back-end emission factor calculated from the
reported emissions and production was equivalent to the
residual HAP levels in the crumb leaving the stripping
operations. Inherent in this analysis was the assumption
that the companies reported total HAP emissions from all
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back-end emission sources, rather than only a portion of
these sources.
Upon receipt of these comments, the EPA again contacted
each EPR and PBR/SBRS production facility to (1) verify the
emissions numbers used to determine the back-end emission
factor, (2) discuss the correlation of the methods used to
estimate the original emission estimates and the residual
organic HAP test methods undergoing validation,
(3) determine the appropriate production, including oil
extender weight, to use in determining the emission factor,
(4) obtain information related to residual HAP remaining in
the product after finishing, and (5) obtain short-term
residual HAP information to be used in the adjustment of
annual emissions to monthly.
After obtaining this information, the EPA recalculated
the MACT floors for each subcategory. It should be noted
that only one facility indicated that the original emission
estimates were calculated in a manner that was inconsistent
with the residual organic HAP test methods. Two PBR/SBRS
companies and one EPR company provided detailed short-term
residual HAP data to allow the conversion of the annual data
to a monthly limit. The resulting monthly limits were
8 kg/Mg for EPR and 10 kg/Mg for PBR/SBRS.
While no comments were received criticizing the MACT
floor analysis for SBRE, the change to a monthly average
limit resulted in a change in the SBRE limit. In the
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determination of the original SBRE back-end MACT floor,
residual HAP data were used from three of the four
facilities. The fourth facility provided residual HAP data,
but it was in a monthly average format and could not be used
in the determination of a weekly limit. However, the change
to a monthly limit meant that the data from this facility
could also be used, resulting in a monthly limit of 0.4 kg
styrene per Mg latex for existing SBRE sources.
1.2.5.3 Monitoring requirements
Several comments were received regarding the proposed
crumb and latex sampling requirements. In both instances,
the EPA decided that the changes suggested by the commenters
were technically appropriate, and they did not result in any
detrimental environmental impact.
Specifically, commenters found the requirement to
sample "before any opportunity for emissions to the
atmosphere" to be either unfeasible or unsafe for PBR/SBRS
and EPR and suggested modifications to the proposed sampling
provisions. In response to these comments, the final rule
states that PBR/SBRS or EPR crumb samples must be taken "as
soon as safe and feasible after the stripping operation, but
no later than the entry point for the first unit operation
following the stripper (e.g., the dewatering screen)."
For SBRE, commenters pointed out that a more logical
sampling location for determining the initial HAP
concentration in the SBL is the mixed latex in the storage
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tank feeding the coagulator (rather than directly after the
stripper). The EPA agrees with these comments, and the
final rule states that the SBL sampling location must be
prior to any coagulation operations.
Comments were also received opposing the proposed crumb
or latex sampling frequency provisions. Commenters believed
that it is impractical to take a rubber sample each
operating day for every grade of elastomer produced, because
of the time required to reach representative operating
conditions and to run an accurate analytical test.
Suggested alternatives included one test per day, one test
per "campaign," daily sampling that is reduced to weekly
sampling upon demonstration of daily compliance, and daily
sampling with the exception of grades produced for less than
4 hours in a day. Since the variability of the residual HAP
contents between elastomer grades is relatively small, and
since production schedules typically produce very similar
grades of polymer for extended periods of time, the EPA
concluded that reducing the sampling frequency to once per
day for continuous processes would greatly simplify the
rule, while still ensuring that all grades of elastomer
produced are represented. This change is reflected in the
final rule.
Some commenters were concerned that compliance would be
based on one sample per day, and requested that an owner or
operator be allowed to sample crumb or latex more
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frequently, and include the residual organic HAP results of
these samples in the average. While the EPA believes that
the proposed rule did not preclude a company from using more
than one sample per day in determining the (weekly) average,
the language in the rule has been revised to make this
provision clearer.
Several commenters stated that the rule should provide
an allowance for missed or invalid crumb or latex samples.
The proposed rule designated the failure to collect any
single sample an excursion. These commenters suggested that
the EPA should require 75 percent of samples to be
collected.
The EPA recognizes that a number of circumstances could
occur that cause a sample not to be analyzed in accordance
with the rule. These may be in the form of sampling system
malfunctions, mis-analysis, or other problems. The EPA
realizes that there are unique challenges associated with
the sampling of solid polymer, and agrees that problems
could occur that would cause a sample to be missed. The EPA
also recognizes that some of the test methods being
validated to analyze the residual organic HAP in the crumb
take long periods of time to perform, meaning that the
opportunity to obtain a second sample may not be available
if a mis-analysis in the laboratory occurs. While the EPA
expects that sound company procedures could eliminate most
of these and other problems, the EPA agrees that it is
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unreasonable to expect that no problems would ever occur
that result in a missed sample. Therefore, an excursion for
back-end process operations is defined in the final rule as
when either (1) the monthly weighted average is above the
applicable limit, or (2) when less than 75 percent of the
required samples are taken, analyzed, and included in the
monthly average.
At proposal, the EPA specifically requested comments on
the feasibility of the use of computer predictive modeling,
as an alternative to the daily crumb or latex sampling, or
the stripper parametric monitoring compliance alternatives.
Numerous commenters supported the allowance of such systems,
while others expressed reservations. While the EPA believes
that computer predictive modeling may be an attractive
alternative to the periodic sampling and stripper parametric
monitoring compliance options, the EPA is convinced that the
use of computer predictive modeling is so site-specific that
it is not possible to include general requirements for the
use of such a system in subpart U. Nevertheless, the EPA
believes that facilities should have the opportunity to
utilize techniques that are equivalent to the two options of
compliance provided in the proposed rule for facilities
using stripping technology. Therefore, the EPA has included
a third option that provides the opportunity for the site-
specific approval of alternative means of compliance through
the submittal of an alternative compliance plan.
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1.2.6 Wastewater Operations Provisions
Several commenters pointed out that the wastewater
provisions of subpart G that are referenced in section
63.488 of subpart U are the subject of litigation brought by
the Chemical Manufacturers' Association against the EPA.
Consequently, sources subject to these provisions cannot
know what the final wastewater provisions, proposed to be
incorporated into subpart U, will be. These commenters
believed that the EPA should "reserve" the provisions of
section 63.488 of the final rule, pending the outcome of the
litigation.
As part of the HON litigation proposal, the EPA will
request comments specific to the elastomers rule. If
comments specific to the elastomers rule are received they
will be addressed as part of the HON rulemaking actions or
in actions specific to the elastomers rule, depending on the
comments. Therefore, the comment period for this rule will
not specifically be reopened.
The EPA believes that the wastewater provisions and the
other HON provisions should be referenced in the elastomers
rule so that final resolutions of the HON litigation will be
automatically included in the elastomers rule. However,
changes made to the HON will be evaluated by the EPA for
applicability to this rule. The "automatic" part refers to
the fact that text changes will not need to be made to this
rule once the EPA finds, following notice and opportunity
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for comment, the HON changes to be applicable. If the EPA
determines that any changes to the HON are not applicable to
this rule, the elastomers rule will be revised accordingly.
1.2.6.1 Applicability requirements
Comments were received stating that the VOHAP threshold
for regulation of new source wastewacer streams (10 ppmw)
was too restrictive, and that the EPA has not provided an
economic justification regarding the achievability of the
limit. Another comment was received stating that many
elastomer product process wastewater streams will have VOHAP
concentrations less than 50 ppmw, and monitoring and
recordkeeping requirements are not needed for these streams.
This comment recommended that the EPA exempt from regulation
"any process stream at an affected source with an average
flow rate of less than 0.02 liters per minute or an average
VOHAP concentration of less than 50 ppmw."
The EPA evaluated the new source MACT floor
determinations for wastewater, and determined that no
facility in any subcategory reported wastewater controls
equivalent to the new source levels. In fact, no facility-
wide wastewater controls greater than the existing source
HON limitations were reported. Therefore, the EPA believes
that this comment is valid, and has changed the final rule
so that the new sources are subject to the same wastewater
requirements as existing sources.
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In the proposed rule, the definition of wastewater
stated that a stream must contain at least 5 ppmw of VOHAP
and have a flow rate of 0.02 liter per minute. Given the
change in the definition of a Group 1 wastewater stream for
new sources, the EPA has revised the definition of
wastewater in the final rule in accordance with the
commenter's suggestion.
1.2.7 Equipment Leak Provisions
One commenter requested that the rule include an
exclusion for reciprocating pumps that must leak small
quantities of product to lubricate and cool the shaft and
seal areas. The EPA agrees that an exemption for the
situation described by the commenter is reasonable. The EPA
reached a similar conclusion in the proposed Polymers and
Resins IV regulation (subpart V). Therefore, section
63.502(f) has been added that exempts these reciprocating
pump systems.
Several commenters stated that 3 years should be
allowed for compliance with equipment leak provisions for
compressors (instead of 6 months) under certain
circumstances. The EPA agrees with the commenters, and has
amended the compliance schedule for compressors in the
following situations: (1) existing reciprocating compressors
which would require design modifications to connect to a
closed-vent or recovery system; and (2) systems where
existing compressors would be replaced.
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1.2.8 Emissions Averaging Provisions
Several commenters requested that batch front-end
process vents be eligible to average emissions. The EPA had
not allowed emissions averaging of batch front-end process
vents at proposal because the EPA considered the accuracy
and consistency needed for emissions averaging to be greater
than that needed for applicability determinations. However,
upon reconsideration, the EPA determined that the accuracy
and consistency needs of emissions averaging could be met by
applying a "discount" factor to calculated emissions or by
requiring direct measurement of emissions. Therefore, the
final rule allows emissions averaging of existing batch
front-end process vents.
1.2.9 Monitoring
Many commenters requested that the proposed rule allow
excused excursions in the same way that the HON rule allows
excused excursions. In the final rule, the EPA decided to
excuse a certain number of excursions for each reporting
period. This decision was based on data and information
presented during public comments on the HON and reiterated
in public comments received on this rule, and during
industry meetings held subsequent to proposal that indicated
that a certain number of excursions could be expected even
with properly operated pollution control devices. The EPA
also concluded that not allowing excused excursions would
impose significant additional capital and operating costs on
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the affected source for only negligible corresponding
reductions in air emissions. As is always the case, a State
has the discretion to impose more stringent requirements
than the requirements of NESHAP and other federal
requirements and could choose not to allow the excused
excursion provisions of this rule.
The EPA considered the number of excused excursions
that would be most appropriate for this standard and
determined that the number of excursions allowed in the HON
would be reasonable. Therefore, the final provisions allow
a maximum of 6 excused excursions for the first semiannual
reporting period, decreasing by 1 excursion each semiannual
reporting period. Starting with the sixth semiannual
reporting period (i.e., the end of the third year of
compliance) and thereafter, affected sources are allowed one
excused excursion per semiannual reporting period.
1.2.10 Recordkeeping and Reporting
Several commenters stated that the recordkeeping
and reporting requirements of the proposed rule were
extremely burdensome and requested that the EPA reduce the
burden. The EPA reexamined the recordkeeping and reporting
requirements of the rule after proposal and determined that
certain changes could be made without impacting the
enforcement of this rule. The following changes were made
to reduce the recordkeeping and reporting burden:
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(1) The requirement to submit an Initial Notification
has been eliminated;
(2) The requirement to submit an Implementation Plan
has been eliminated;
(3) The requirement to record monitored parameters
every 15 minutes has been removed. The final rule requires
hourly recording of monitored parameters in place of the
15-minute records required in the proposed rule. The EPA
considers the recordkeeping and reporting requirements of
the final rule the minimum necessary to ensure compliance
with the final standards.
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2.0 APPLICABILITY
2.1 SELECTION OF SOURCE CATEGORY
2.1.1 Elastomer Production Definitions
Comment: Several comments were received regarding the
use of the term "copolymer" in the definition of several
elastomer products. The commenters indicated that the use
of copolymer suggests the combination of two polymers, while
many elastomers are produced with more than two polymers.
Two commenters (IV-D-8 and IV-D-15) pointed out that this is
the case for the definitions of styrene-butadiene latex and
nitrile-butadiene latex. Commenter IV-D-8 suggested
replacing "copolymer" in the styrene-butadiene latex
definition with the term "polymers that primarily contain
butadiene and styrene." Similarly, commenter IV-D-5
recommended revising the definition of styrene-butadiene
rubber to say "means a polymer consisting primarily of
styrene and butadiene monomer units". Three commenters (IV-
D-17, IV-D-12, and IV-D-10) stated that the definition of
"ethylene-propylene rubber" as proposed is too restrictive,
and that it should be revised to provide for the use of
alternate third monomers. The third monomers listed in the
proposed definition should be used as examples. Another
commenter (IV-D-17) supports the proposed definition of
"butyl rubber," which also uses the term copolymer.
Response: The EPA intended that subpart U cover
products that were clearly one of the listed elastomer
products, but that may have used one or more additional
monomers in their production. Therefore, the EPA has
modified the definitions of ethylene-propylene rubber,
nitrile-butadiene rubber and latex, styrene-butadiene latex.
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styrene-butadiene rubber by emulsion based on these
comments.
Comment: One commenter (IV-D-18) stated that the
definition of "epichlorohydrin elastomer" could be
misinterpreted to include epoxy resins, and in order to
avoid this result, the definition should be revised.
Response: The definition of epichlorohydrin has been
revised to specifically indicate that epoxy resins are not
epichlorohydrin elastomers.
Comment: One commenter (IV-D-18) stated that the
definition of "polysulfide rubber" should be revised so that
it is based on chemical composition, and so that it does not
include information on manufacturing methods, which is
extraneous.
Response: The EPA agrees with the commenter that the
definition of polysulfide rubber needs to be revised to
reflect chemical composition rather than manufacturing
methods. Therefore, the definition of polysulfide rubber
has been changed to refer to polymers produced by the
reaction of sodium polysulfide and chloroethyl formal.
2.1.2 Other Processes
Comment: The proposed rule did not apply to facilities
producing styrene-butadiene resins and copolymers. At
proposal, the EPA requested comment on specific methods to
distinguish between elastomers and resins/copolymers (60 FR
30814).
Three commenters (IV-D-5, IV-D-10, and IV-D-20)
responded to the EPA's request for methods to distinguish
between elastomers and resins/copolymers. Two of these
commenters (IV-D-5 and IV-D-10) provided suggested
definitions for "elastomer" that are based on glass
transition temperature and use. Commenter IV-D-10 also
suggested a definition of "resin," which was based on the
same criteria. A fourth commenter (IV-D-1) had no
suggestions beyond those already considered by the EPA.
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Another commenter (IV-D-20), whose facility uses
styrene, isoprene, and/or butadiene to build thermoplastic
elastomer resins/copolymers, also provided input to this
issue. The commenter stated that although the EPA has
indicated that the rule is not intended to apply to the
facility in question, the commenter believes that the rule
does inadvertently apply. The commenter provided several
suggestions to distinguish between the regulated processes
and the commenter's processes. The commenter proposed that
the EPA provide an exclusion for facilities that meet all of
the following criteria: (1) the process unit manufactures a
block polymer; (2) the manufactured copolymer does not
require vulcanization to make useful products; (3) the
process is operated to achieve at least 99 percent monomer
conversion; and (4) the process unit does not recycle
unreacted monomer back to the process.
Response: The suggestions made by the commenters were
all incorporated into the rule. The definitions of
elastomer and resin in section 63.482 of the final rule are
as follows:
Elastomer means any polymer having a glass
transition temperature lower than -10°C, or a glass
transition temperature between -10°C and 25°C that is
capable of undergoing deformation (stretching) of
several hundred percent and recovering essentially when
the stress is removed. For the purposes of this
subpart, resins are not considered to be elastomers.
Resin means a polymer that is not an elastomer.
Following are characteristics of resins and the
production of resins: (l) the polymer that is produced
is a block polymer,- (2) the manufactured polymer does
not require vulcanization to make useful products; (3)
the polymer production process is operated to achieve
at least 99 percent monomer conversion; and (4) the
polymer process unit does not recycle unreacted monomer
back to the process.
The definition of existing affected source includes the
combination of EPPUs at a plant site. Since an EPPU is
defined as a process unit that produces an elastomer as its
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primary product, and since the definition of elastomer now
clearly does not include resins, the EPA believes that the
final rule explicitly defines those sources it intends to
regulate with regard to elastomers and resins.
Comment: As discussed in the previous comment and
response, some commenters provided input regarding the
distinction between elastomers (which were subject to the
proposed subpart U) and resins/copolymers (which were not
subject to the proposed subpart U). However, several
commenters (IV-D-3, IV-D-5, IV-D-10, IV-D-18) commented on
whether resins should be covered by subpart U. Three of
these commenters believe that some or all styrene-butadiene
resin production should be covered by this regulation. One
of these,commenters (IV-D-10) believed that styrene-
butadiene and polybutadiene resins should be included in the;
regulation when they are produced under substantially the
same conditions and in the same process equipment as
styrene-butadiene and polybutadiene elastomers. Another
commenter (IV-D-3) opposed any regulation that would require
a company to comply with different MACT standards for the
same equipment or emission points. This commenter believed
that the EPA should focus on the manufacturing process to
determine source categories, rather than end uses. The
third commenter (IV-D-5) recommended that the production of
these resins be included in the standard, but exempted from
the control requirements since they are not considered to be
significant sources of HAP emissions. These commenters
claimed that the development of a separate standard for
these resins or the application of case-by-case MACT would
be unnecessary and burdensome. The fourth commenter (IV-D-
18) supported the exclusion of certain resins and copolymers
from the standard, because further information must be
gathered to determine how these other production processes
should be regulated. Still another commenter (IV-D-25)
stated that the production of elastomers and
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resins/copolymers should be grouped together into one source
category. This cotnmenter suggested that the regulation
could be promulgated while exempting styrene butadiene
resins and copolymers, and then later reviewed for possible
inclusion of these compounds.
Response: The EPA agrees with the argument made by
commenter IV-D-18 regarding the lack of information for
resin and copolymer production processes. The initial
source category list, published on July 16, 1992 (57 FR
31576), included the source categories of "styrene-butadiene
rubber and latex production" and "polybutadiene rubber
production." While the descriptions of these source
categories in EPA's "Documentation for Developing the
Initial Source Category List" (EPA-450/3-91-030) could be
interpreted to include a range of polymers and copolymers,
the EPA intended to address and therefore focused only on
the production of "rubber" and "latex" products.
In its initial information gathering efforts, the EPA
attempted to obtain data for every known styrene-butadiene
and polybutadiene rubber and latex process in the United
States. During these efforts, some information was obtained
for processes that manufacture resins, copolymers, or other
polymers that are not generally considered to be elastomer
(i.e., rubber or latex) products. While the EPA recognized
similarities in the processes, no effort was made to obtain
information on all producers of these polymers, or to ensure
that the data acquired were representative of the entire
resin or copolymer industry. Since the data for the non-
rubber and non-latex processes were not considered in the
development of the Polymers and Resins I regulation, the EPA
does not believe that it is appropriate to require resin and
copolymer production to be subject to subpart U.
The EPA appreciates the concern of the cotnmenters
regarding the compliance difficulties that could arise when
resins or copolymers are produced in equipment that is also
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used to produce rubber or latex. The EPA maintains that the
proposed regulation addressed this situation through the
designation of a production unit as an elastomer product
process unit (EPPU), based on the primary product of that
unit. However, the EPA also recognized that the proposed
provisions related to the determination of a primary product
for "flexible operation units" were unclear. Therefore,
portions of section 63.480 have been amended to clarify this
issue. Specifically, section 63.480(f)(2) contains revised
provisions for the determination of the primary product for
flexible operation units. In addition, section 63.480(e)
has been added to clarify the applicability of subpart U to
equipment producing non-elastomer products within an EPPU
that is subject to subpart U. These sections are summarized
in the following paragraphs.
If a process unit produces both an elastomer and a
resin/copolymer, but the primary product is an elastomer,
then the unit is an EPPU and subject to the provisions of
subpart U at all times. In other words, if control is
required on an emission point for an EPPU that also produces
resins, the control must continue to be operated when resin
is being produced. The only exception to this requirement
is for non-elastomer polymers that are finished in back-end
process operations of an EPPU.
The back-end process operation provisions in section
63.493 [old section 63.487] of subpart U were developed
based on the ability to remove residual HAP from the rubber
or latex entering the back-end operations. Since the
residual HAP content of resins were not included in the
analysis, and since the EPA believes the ability to strip
residual HAP varies between resin and elastomers, the EPA
concluded that it is not appropriate for the residual HAP
content of resins to be included in the monthly back-end
residual HAP average. Section 63.494 [old section 63.487-1]
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has been revised to clearly exempt resins from inclusion in
the back-end monthly average.
The EPA also agrees with commenter IV-D-25 that a
future, more detailed, analysis of emissions and emissions
controls for the styrene butadiene resins and copolymer
industry could result in the expansion of the applicability
of subpart U. However, styrene butadiene resin and
copolymer production is not currently on the EPA's list of
major source categories (57 FR 31576), and there are no
plans to study this industry at this time.
Comment: One commenter (IV-D-22) expressed concern
that the proposed rule inadvertently covers the small liquid
polybutadiene resin process at the commenter's facility.
The commenter stated that the rule was intended to apply to
units that produce solid material or latex, rather than
liquid material, and the provisions are consequently
inappropriate to this facility. The commenter stated that
its primary customer is the Department of Defense (DOD),
which requires extensive testing and approval of any process
change. It could be infeasible for the commenter's facility
to meet the requirements of the proposed rule, if DOD were
to refuse permission for a process change. Finally, the
commenter stated that the requirements would impose
significant costs that would not be matched by corresponding
environmental benefit.
Response: Subpart U was not intended to apply only to
elastomer processes that produce solid materials or latexes.
Whether a source is subject to subpart U is determined based
on the application of several criteria, including (1) does
the product meet the definition of an elastomer product?,
(2) is the source located at a major source plant site?, and
(3) does the source use an organic HAP? The EPA cannot
determine whether the commenter's facility meets all these
criteria based on the information provided, but the fact
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that the product is not a solid or latex has no bearing on
the affected source determination.
However, the form of the product does have a bearing on
how specific sections of the rule should apply. The EPA
agrees that since the final product is a liquid, the "back-
end" provisions of 63.487 were not appropriate. Therefore,
the final rule exempts processes producing liquid rubber
products from the requirements of section 63.493 [old
section 63.487] . The rule has also been modified to
indicate that if both liquid and solid rubber products are
produced in the same elastomer product process unit, the
residual HAP content of the liquid rubber product is not to
be included in the monthly weighted average residual HAP
determination.
Comment •. Two commenters (IV-D-24 and IV-D-14)
expressed concern with the applicability of standards to
facilities where nitrile butadiene rubber and latex, and
styrene butadiene rubber and latex are produced as
intermediates in the production of aerylonitrile butadiene
styrene (ABS). One commenter (IV-D-24) noted that the
intent expressed in the preamble to Polymers and Resins IV
is for ABS production to be covered under Polymers & Resins
IV, not Polymers & Resins I. This commenter believed this
should be clearly stated in both standards to avoid
confusion. To this end, the commenter recommended the
inclusion in each rule of a definition of primary product,
whereby the primary product of a production unit is
identified as the final product leaving the unit either for
sale or for further processing at a facility not regulated
under a polymers and resins rule. The other commenter (IV-
D-14) stated that since information submitted to the EPA by
his company was not used in the development of the standard,
it is unclear whether EPA intended to include the company's
SBL facilities under the Polymers & Resins I standard. The
commenter stated that it was unclear whether the EPA can
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satisfy its statutory requirements for MACT floor
development without considering the data submitted by the
commenter. This commenter requested that, in resolving this
confusion, the EPA develop a single NESHAP to cover
collocated SBL production units and ABS production units, in
order to streamline regulatory burdens. The commenter
stated that, to regulate these integrally related processes
under two standards, would be overly burdensome. The
commenter added that because of the failure to include their
information, it is difficult to fully evaluate either the
effect of the standard on their facility or the methodology.
Response: The EPA agrees with the commenters that the
production of NBR, NBL, and SBL as intermediates in the
production of ABS should be subject to the same regulation
as the ABS production, to avoid the possibility of confusion
as to which rule should apply. Therefore, in subpart V, an
ABS production unit was defined to include the production of
elastomers as intermediates. Also, the production of these
elastomers in this situation has been exempted from the
requirements of subpart U. This does not change the level
of control required of these processes.
2.2 SELECTION OF POLLUTANTS
Comment: Two commenters (IV-D-14 and IV-D-18) stated
that the Polymers and Resins I NESHAP should use the HON
definition for "organic hazardous air pollutant" for clarity
and consistency. One commenter (IV-D-18) articulated five
concerns with the proposed definition. These are: (1) if
more HAP are identified, this definition will not
acknowledge them/ (2) because the definition relies on two
tests to identify an organic HAP, there is potential for
conflict between the tests,- (3) confusion will result from
the requirement for a substance to be "commonly considered"
organic; (4) the definition should not be based merely upon
whether a carbon atom is present; and (5) the proposed
definition could allow the applicability of the rule to
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expand to include organic HAP that exist in trace
quantities, or not at all in these processes. The coramenter
preferred the approach taken in the HON where the organic
HAP are identified in a table.
Response -. In response to requests from commenters, the
EPA has developed a list of known organic HAP for each
subcategory that will be regulated by the elastomers rule.
The list is presented in table 5 of the rule and is referred
to in the revised definition of "Organic HAP" found in
section 63 .482 .
The revised definition was developed using available
process description information received from industry and
gathered from available literature. Because there may be
additional organic HAP present at an affected source that
were not included in table 5, the final rule requires owners
or operators to notify the EPA of the presence of any
additional organic HAP based on the following criteria:
(1) it is knowingly introduced into the manufacturing
process (not including the presence of organic HAP as
impurities), or has been or will be reported under any
Federal or State program, such as TRIS or Title V,- and (2)
it is presented in table 2 of subpart F. The owner or
operator is required to identify these additional organic
HAP in their Notification of Compliance Status.
2.3 SELECTION OF AFFECTED SOURCE
2.3.1 Major Source Criteria
Comment: One commenter (IV-D-23) specifically
requested that the EPA defer the permitting of area sources
in this category as provided for under 40 CFR 70.3(b) (1) and
discussed at 57 PR 32261 (preamble to permit rule). The
commenter said that State agencies are already burdened with
permitting major sources, and the burden of permitting area
sources will not be accompanied by an air quality benefit,
since these sources will be required to comply whether they
have a permit or not.
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Response: As stated in the preamble to the proposed
rule, the EPA is not regulating area sources under this
rulemaking. The final elastomers rule regulates only major
sources, where the area/major source determination is made
for the plant site, not for each individual EPPU at the
plant site. As discussed in the next comment, some
commenters believe that applicability should be based solely
on emissions from the EPPU, rather than the entire plant
site, in the determination of major source. The EPA
suspects that this may be the point of the commenter.
However, as discussed in the response to the next comment,
the EPA believes that major source determinations should be
made on the plant/site level.
Comment: Two commenters (IV-D-26 and IV-D-14)
disagreed with the proposed approach whereby all EPPU at a
major source plant site are subject to the regulation, even
if the EPPU itself is not a major source. The commenters
requested that the EPA set an applicability cutoff of 10
tons per year for the entire production unit in these source
categories, because it is not cost-effective for small
sources to comply with MACT requirements. In addition, one
commenter (IV-D-14) stated that the proposed approach
results in the regulation of area sources without the
requisite finding under section 112(c)(3) of the Act.
Response: The EPA disagrees with the commenters'
interpretation of the definition of major source in section
112(a)(1) of the Clean Air Act. In fact, on July 21, 1995,
in the case of National Mining Association, et al., v.
United States Environmental Protection Agency, 59 F.3d 1351,
the United States Court of Appeals for the District of
Columbia rejected the exact argument made by commenters, and
determined that EPA's definition of major source without
respect to source categories was reasonable.
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2.3.2 Use of Organic HAP
Comment; Three cotnmenters (IV-D-10, IV-D-17, and
IV-D-21) state that the manufacture of some polymers uses
organic HAP as diluents in the process, but not as
reactants, nor are they produced as products or by-products.
According to the applicability criteria in the proposed
rule, these processes would not be subject to the proposed
rule. Commenter IV-D-17 stated that since the processes
were used in the basis for development of the rule, the EPA
must have intended that they be subject. The commenter
recommended that the rule be revised to include the use of
an organic HAP as a diluent as a basis for applicability of
subpart U. In addition, one commenter (IV-D-14) expressed
support for the concept that an EPPU that does not use or
create an organic HAP should not be subject to the rule.
Response: As pointed out by commenter IV-D-17, the EPA
intends that elastomer processes where the reaction occurs
in a HAP solvent (i.e., solution processes) be subject to
the rule, even if no reactants are themselves HAP. This is
evident by the inclusion of requirements in the proposed
subpart U for the production of ethylene propylene rubber
(EPR). HAP emissions identified from the EPR process are
only a result of the use of hexane as the reaction solvent.
HAP are not used as a reactant, and such facilities do not
manufacture a HAP as a by-product or co-product. However,
the proposed rule could be read to exclude EPR processes
from subpart U. Because this was not the EPA's intention,
it is clear that a change to the rule is necessary.
The first approach considered was to make the rule
applicable to sources that use an organic HAP in any manner.
Other approaches considered were to base applicability on a
revised list of specific uses of HAP (such as suggested by
the commenter), or on usage of a specified amount of HAP.
The EPA rejected the list of specific uses due to the
possibility of new elastomer production processes that may
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use (and potentially emit) organic HAP in manners other than
those that would be on the list. A prime example of this is
addressed in the subsequent comment. The commenter (IV-D-
21) is constructing a gas-phase, fluidized bed process to
manufacture EPR. Based on the current uses of organic HAP
that would be on a list (as a reactant and as a "diluent"),
this facility would not be subject to the regulation.
However, there is a significant potential for HAP emissions
from this process, due to the use of HAP in another manner.
(It should be pointed out that the facility mentioned by the
commenter is planning to implement extensive emission
controls).
The EPA believes that the most reasonable means to
ensure the coverage of HAP emissions from major sources
subject to the rule is to include the use of HAP in any
manner as one of the applicability criteria. The final rule
has been changed to reflect this approach.
Comment; One commenter (IV-D-21) is constructing a
facility that will manufacture ethylene-propylene rubber
using a gas phase, fluidized bed process technology. This
proprietary gas phase technology is fundamentally different
from the solution processes examined by the EPA in
developing the proposed rule, and because of this, it is not
clear whether, or how, the proposed rule would apply to this
facility. In particular, the use of HAP in the
manufacturing process is much less than in the solution
process. The commenter believes that the facility should be
considered an affected source under the Polymers and Resins
I NESHAP, but that changes should be made in the rule to
reflect the fundamental process differences, or that the
manufacture of EPR by the gas phase process should be
regulated under a separate subcategory.
Other than the general applicability comment discussed
in the previous comment, the commenter had two major
concerns specifically related to their gas phase process.
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First, the coinmenter indicated that the control device of
choice for the front-end process vents in this process is a
flare, primarily due to the ability of the flare to control
the small continuous streams a well as much larger streams
resulting from startup, shutdown, and malfunction conditions
in the gas phase, fluidized bed reactor. The commenter
indicated that the stream being controlled by the flare will
contain halogenated compounds, sometimes exceeding the 0.45
kb/hr threshold. The commenter said that the design of an
incinerator with a scrubber system to comply with the
provisions of section 63.113(c), while still managing the
highly variable emissions from their process, was
impractical.
The second concern was that the back-end process
provisions were designed with an entirely different type of
process in mind. The commenter pointed out that the gas
phase process has no latex or dry crumb rubber, nor does it
have a stripper. This led the commenter to the conclusion
that compliance with the back-end limits was not 'possible,
and that the gas phase fluidized bed process should be
exempt for these requirements.
Response: The EPA agrees with the commenter that the
uniqueness of this process should be considered in
determining the final requirements for EPR producers. The
EPA does not, however, believe that the creation of a
separate subcategory is necessary. The majority of the
applicability and control requirements in the rule are
general, and the EPA believes can be applied to the
commenter's facility.
The following addresses two areas where the commenter
was particularly concerned. First, the commenter indicated
a flare was the correct control device for this process.
However, the commenter believes that the flare inlet stream
may contain sufficient halogens to be classified as a
halogenated vent stream, meaning that a flare could not be
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used. The EPA maintains that this is no longer an issue,
due to a change in the continuous process vent provisions
related to halogenated vent streams at EPR facilities. As
described in section 4.2, the EPA determined that routing to
a flare or boiler, without additional control of the
hydrogen halides created during combustion, would be the
MACT floor for halogenated vent streams at existing EPR
facilities.
The second concern of the commenter was related to the
back-end residual organic HAP limitations. The EPA agrees
that the commenter's facility does not include process
operations similar to the back-end process operations at the
other EPR facilities. Therefore, the EPA concludes that the
gas-phased process should not be subject to these
provisions, and has exempted gas-phased polymerization
reactions from section 63.493.
2.3.3 Definition of Affected Source and Elastomer Product
Process Unit (EPPU)
Comment: Several comments were received regarding the
definitions of affected source, elastomer product process
unit (EPPU), and process unit, and the relationship of these
definitions to the applicability provisions in section
63.480. Two commenters (IV-D-5 and IV-D-8) expressed
concern about the potential for inappropriate regulation of
sources caused by misapplication of the term "affected
source." One commenter (IV-D-5) is concerned about the
potential for unintended regulation of latex-producing back-
end equipment, which should be exempt under section 63.487.
This commenter believes that this may occur when equipment
other than raw material storage is shared, the primary
product of the process unit is rubber, and the back-end
process equipment produces latex. This commenter stated
that this is a result of the interaction between definitions
for "affected source" and "elastomer product process unit,"
and that this situation should be clarified by the EPA. The
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other commenter (IV-D-8) stated that in cases where some
parts of a facility are not subject to the standard (e.g.,
SBL back-end), the commenter suggested that the term
"affected source" could bo interpreted to mistakenly include
parts of the facility that are not subject, and to impose
burdensome requirements. In addition, this commenter was
concerned that the term "affected source" could also cause
confusion in cases where process equipment is used in two
processes, and the equipment is subject to requirements when
used for one process but not the other. This commenter
suggested that where such potential for ambiguity exists,
the EPA should instead use the term "source" or "source
subject to this subpart."
Response: The EPA agrees with the commenter that the
meaning of affected source was not clear in the proposed
rule and it has been clarified in the final rule. The
definition of affected source included in section 63.482 of
the proposed rule has' been revised to refer to section
63.480(a). The provisions in section 63.480(a),'which at
proposal tied applicability to the existence of one or more
EPPUs, have been revised to define the applicability in
terms of the affected source. Also, the provisions in
proposed section 63.480(b) which described the affected
source, have been removed.
In the final rule, under section 63.480(a), the
existing affected source is defined as each group of one or
more EPPUs that manufacture the same elastomer product as
their primary product, and (1) are located at a major source
plant site, (2) are not exempt, and (3) are not part of a
new affected source. This means that each plant site will
have only one existing affected source in any given
subcategory.
If a plant site with an existing affected source
producing elastomer A as its primary product constructs a
new EPPU also producing elastomer A as it primary product,
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the new EPPU is a new affected source if the new EPPU has
the potential to emit more than 10 tons per year of a single
HAP, or 25 tons per year of all HAP. In this situation, the
plant site would have an existing affected source producing
elastomer A, and a new affected source producing
elastomer A. Each subsequent new EPPU with potential HAP
emissions above the levels cited above would be a separate
new affected source.
New affected sources are also created when an EPPU is
constructed at a major source plant site where the elastomer
product was not previously produced, with no regard to the
potential HAP emissions from the EPPU. Another instance
where a new affected source is created is if a new EPPU is
constructed at a new plant site (i.e., green field site)
that will be a major source. The final manner in which a
new affected source is created is when an existing affected
source undergoes reconstruction, thus making the previously
existing source subject to new source standards. This
approach to defining new affected source was selected in
order to make subpart U more consistent with the HON.
This approach to defining a new affected source was
selected in order to make subpart U more consistent with the
HON. This standard differs from the HON, however, in that
it applies to multiple source categories. Thus, unlike the
HON, a newly added EPPU at a facility is covered by this
rule even if that EPPU is in a different source category
form the existing EPPUs at the facility. It is the EPA's
position that the addition of a process unit in a different
source category is a new source and must meet the
requirements for new sources even though the EPPU may have
the potential to emit less than 10 tons per year of a single
HAP or 25 tons per year of all HAP. Indeed, if a source
covered by another MACT standard (i.e., a different source
category) were built at a HON facility, that source would be
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subject to the new source requirements under that MACT
standard.
One cotnmenter requested clarification on the boundaries
of the EPPU when multiple process units share equipment
(i.e., beyond raw material or product storage vessels). In
the proposed rule, the concept of shared equipment was
discussed under the definition of affected source. It is
more appropriate to discuss this issue in the definition of
EPPU, and the final definitions of affected source and EPPU
have been revised to reflect this decision, as discussed in
later comments.
Comment: One commenter (IV-D-14) stated that the
definition of "elastomer product process unit" should be
significantly revised to be clearer and more specific. The
commenter indicated that the revised definition should focus
on establishing battery limits of the process affected by
the rule. The commenter suggested that this rule should
have separate definitions for source and for elastomer
product process unit, as was done in the HON.
The commenter recommended that the definition of
"elastomer product process unit" not reference section
63.480(b), and that it incorporate the list of equipment
that makes a process unit from the HON definition of
"chemical manufacturing process unit." Two other commenters
(IV-D-5 and IV-D-18) also found the reference to "all
equipment identified in section 63.480(b)" confusing,
because the reference lists sources of emissions, and not
necessarily equipment. One of the commenters stated that
section 63.480(b) includes "wastewater and associated
treatment residuals," and the cotnmenter stated that it is
inappropriate for wastewater to be included in the
definition of equipment that makes a product.
One commenter (IV-D-14) stated that the paired
definitions of "process unit" and "EPPU" within the rule are
confusing. The commenter believes that it would be clearer
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to have a single consolidated definition to cover the
concepts of process unit and EPPU.
Response: The EPA agrees with many of the suggestions
for clarification submitted by the commenters and the
definition of EPPU in section 63.482 has been clarified in
the final rule. The revised definition of EPPU is included
below along with a discussion of the changes made to the
definition.
Elastomer product process unit (EPPU) means a collection of
equipment assembled and connected by pipes or ducts used to
process raw materials and to manufacture an elastomer
product as its primary product. This collection of
equipment includes process vents,- storage vessels, as
determined in section 63.480(g); and the equipment (i.e.,
pumps, compressors, agitators, pressure relief devices,
sampling connection systems, open-ended valves or lines,
valves, connectors, instrumentation systems, surge control
vessels, and bottoms receivers that are associated with the
elastomer product process unit) that are subject to the
equipment leak provisions as specified in section 63.502.
Compounding units, spinning units, drawing units, extruding
units, and other finishing steps are not part of an EPPU.
In addition, a solid state polymerization unit is not part
of an EPPU.
The EPA agreed with the commenter that the definition
of EPPU should include a list of the collection of equipment
that comprises an EPPU, rather than have the list included
in section 63.480. Also, the EPA agreed with the commenters
that wastewater operations should not be defined as part of
the EPPU. Therefore, emissions points associated with
wastewater operations were removed from the collection of
equipment that was included in the revised definition of
EPPU. Wastewater operations treating, storing, or otherwise
handling wastewater originating at an EPPU are included in
the affected source, but not in the EPPU.
In addition, the EPA has clarified the difference
between the terms process unit and EPPU in the final rule.
A discussion of the changes made to the definition of EPPU
is presented above. At proposal, the term process unit
meant equipment used to manufacture an intended elastomer
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product. This definition overlapped with the definition of
EPPU and did not account for equipment used to manufacture a
product which may or may not be an elastomer product.
Therafore, the EPA revised the definition of process unit in
the final rule as follows:
Process unit means a collection of equipment assembled
and connected by pipes or ducts to process raw
materials and to manufacture a product.
This definition is broad and includes EPPUs as well as
process units used to manufacture nonelastomer products. As
explained below, all equipment that is shared/connected,
except for storage vessels, which are discussed in section
63.480(g), would be considered one process unit. The owner
or operator would determine the primary product of the
process unit according to the provisions in section
63.480(f), which is discussed in the next comment.
In the proposed rule, the concept of shared equipment
was discussed under the definition of affected source. It
is more appropriate to discuss this issue in the definition
of EPPU, and the final definitions of affected source and
EPPU have been revised to reflect this decision. In other
words, if two process units share the same dryer, then those
two process units are "connected" and are considered to be a
single process unit. If two process units only share a raw
material storage vessel, then each process unit is
considered a separate entity. The raw material storage
vessel would be assigned to one of the process units, as
discussed earlier.
Comment: One commenter (IV-D-23) recommended that
because the MACT floors and control levels were defined on a
subcategory basis, the definition of "affected source"
should be revised to reflect these subcategory
determinations.
Response: The EPA agrees with the commenter that the
affected source should duplicate the source definition used
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in the MACT floor determinations. While the EPA maintains
that the proposed rule defined affected source on a
subcategory basis, it understands how the proposed affected
source definition could have been misinterpreted. In the
changes to the affected source and EPPU definitions
discussed above, the EPA believes that the fact that the
affected source is defined on a subcategory basis is clear.
However, it should be pointed out that an affected source is
defined based on the "elastomer product," where the 12
elastomer products defined in the rule correspond to the 12
elastomer subcategories.
Comment: One commenter (IV-D-18) supported the EPA's
proposal that the primary product is the determining factor
in establishing applicability of the Polymers and Resins I
rule.
Response: The use of the primary product of an EPPU to
determine applicability has been retained in the final rule.
However, in the review of the use of primary product in
establishing applicability, the EPA realized that the
determination of the primary product of flexible operation
units had its shortcomings. In the proposed as well as the
final rule, the primary product for flexible operation units
is determined based on the expected operations for the 5
years following the promulgation date for existing sources,
and for the first 5 years after the initial startup for new
affected sources. The purpose of these provisions is to
exclude the owner or operator of the EPPU from having to
redetermine their primary product as a result of a small
process change. The 5-year time frame was used to be
consistent with the operating permits program.
While the intent of these provisions has not changed,
the EPA has revised section 63.480 of the final rule in
order to improve the determination of the primary product
for flexible operation units. In addition, provisions were
also added to the final rule for demonstrating compliance
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with the rule during those periods when a flexible operation
unit is producing a product other than an elastomer product.
These provisions allow the owner or operator to establish
new parameter monitoring levels or demonstrate that the
parameter monitoring levels established for the primary
product are appropriate for those periods when products
other than the primary product are being produced.
Comment -. One commenter (IV-D-18) stated that the rule
is not entirely clear regarding how a process unit
consisting of some batch and some continuous operations will
be regulated. The commenter requested confirmation that the
following points were interpreted correctly: (1) it is
possible to have a batch unit operation within a continuous
EPPU; (2) it is possible to have a continuous unit
operation within a batch EPPU; (3) within an EPPU, process
units from a batch unit operation are batch process vents,
and process vents from continuous unit operations within the
same EPPU are continuous process vents,- and (4) the
determination of whether an EPPU is batch or continuous is
based on the overall nature of the process unit.
Response: The commenter is mistaken on one fundamental
issue. An EPPU is not designated as batch or continuous.
Therefore, points 1, 2, and 4 are not relevant. Whether the
continuous process vent provisions in section 63.485 or the
batch vent provisions in section 63.486 apply to a
particular process vent is based on the unit operation from
which the vent originates. It is possible to have a
combination of batch and continuous process vents in the
same EPPU. In fact, this is quite common in the elastomer
production industry, as the reactors are operated as batch
unit operations, while the stripping, material recovery, and
finishing unit operations are continuous. Therefore, the
commenter's point 3 is correct.
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2.4 MODIFICATION AND RECONSTRUCTION
Comment: Several commenters (IV-D-10, IV-D-14, IV-D-
17, and IV-D-18) stated that paragraphs 63.480(g)(1) and
(g)(2), which apply new source requirements to the
construction or reconstruction of any affected source,
should be revised to specify that an addition or change
triggers applicability of new source requirements only if it
is an affected major source. According to one of the
commenters (IV-D-17), these provisions are contrary to
sections 112(g) and 112(i)(l) of the CAAA, as section 112(g)
restricts the applicability of new source requirements to
the construction or reconstruction of a major source.
Another commenter (IV-D-12) indicated that the determination
of whether new source standards apply should be tied to a
significant increase in emissions.
Response: The EPA reviewed the provisions of the
proposed rule for new and existing source requirements for
changes made at major plant sites subject to existing source
requirements. These provisions were in section 63.480(g)
and (h) of the proposed rule; they are in section 63.480(i)
of the final rule.
The EPA agrees that the addition of an EPPU that
manufactures an elastomer product currently produced at an
existing plant site should be subject to new source
requirements only when the addition has emissions above the
major source levels. [Note: Major source levels refers to
the potential to emit 10 tons per year or more of any HAP or
25 tons per year or more of. any combination of HAP.] Such
an addition would simply be a modification to an existing
affected source unless it, in and of itself, is a major
source. When, however, a source is added that produces an
elastomer not currently produced at the facility, such
source cannot be considered a modification to an existing
affected source, even if it emits less than 10 tons per year
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of HAP. Such a source can only be considered a new affected
source.
It is important to note that the approach adopted by
this rule and in subpart V is not inconsistent with the HON,
but is simply the logical extension of the approach taken in
the HON. Unlike the HON, in this rule and other multi-
source- category rules, a subsequent facility addition
subject to the standard could produce an elastomer not
currently being produced at the facility (i.e., in a
different source category). The analogous situation under
the HON would be the addition of a process unit emitting 9
tons per year of HAP to a HON facility. Were construction
on such a unit commenced after the date of proposal, the
unit would be subject to the new source requirements. The
final provisions for section 63 .480 (i) (1) (i) are as follows;
(i) If an EPPU is added to a plant site, the
addition shall be a new affected source and shall be
subject to the requirements for a new affected source
in this subpart upon initial startup or by [insert
promulgation date], whichever is later, if the addition
meets the criteria specified in paragraphs (i) (1) (i) (A)
through (i)(l)(i)(B) and either (i)(1)(i)(C) or
(i)(1)(i)(D) of this section:
(A) It is an addition that meets the definition
of construction in section 63.2 of subpart A;
(B) Such construction commenced after June 12,
1995; and
(C) The addition has the potential to emit 10
tons per year or more of any HAP or 25 tons per year or
more of any combination of HAP, and the primary product:
of the addition is currently produced at the plant site
as the primary product of an affected source; or
(D) The primary product of the addition is not
currently produced at the plant site as the primary
product of an affected source, and the plant site
meets, or after the addition is constructed will meet,
the definition of major source in §63.2 of subpart A.
Comment: Two commenters (IV-D-5 and IV-D-10) suggested
that a provision be added to the rule allowing the owner or
operator of a new or modified source to establish a weekly
weighted average limit for all back-end operations. This
limit would incorporate limits for new and existing back-end
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operations by prorating the different limits by the amount
of latex processed or rubber produced. The overall limit
would be met by all operations, rather than having separate
limits for the new and existing operations. The commenters
claim that this approach would not result in increased
emissions, and could potentially result in decreases.
Another commenter (IV-D-12) stated that since the EPA has
established a single back-end standard, modifications
downstream of the point of compliance should not trigger new
source standards.
Response: The commenters' suggestion is not possible.
The EPA recognizes that this comment is based on section
63.480(g)(2) of the proposed rule, which required changes at
an existing affected source to be subject to new source
requirements if certain conditions were met. In fact, this
comment pointed out an error in the proposed rule. A single
affected source cannot be subject to a combination of
existing and new source requirements. An entire source must
either be a new source or an existing source. Therefore,
the provisions referenced earlier (which are in section
63.480(i) of the final rule) were modified to clarify that
the new or existing source requirements apply to the entire
affected source. The EPA disagrees that back-end
modification should not trigger new source standards. If
these modifications meet the requirements if section
63.480(i), they will trigger the new source standards.
2.5 IMPACTS
Comment: The commenter (IV-D-11) claims that
assumptions made in the Basis and Purpose document do not
reflect current industry operations (e.g., global demand for
EPR is at an all-time high, and most facilities are near
maximum capacity), and the commenter believes that the
proposed standards could place EPR producers at an economic
disadvantage.
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Response: As discussed in the Basis and Purpose
document for the proposed regulation (page 7-1), no impacts
were assessed for new source regulatory alternatives because
no new growth was expected in the near future. The Basis
and Purpose Document referred the reader to the
Supplementary Information Document for the proposed
standards, which contained a. memorandum discussing the
potential for new sources. The factors outlined in this
memorandum for the no growth assumption were that: (1) The
current demand is well below capacity for most types of
synthetic rubber, (2) synthetic rubber production has become
a global market, and there is also a great deal of
unutilized capacity in other areas of the world, and (3) new
elastomers products (that would not be included in one of
these nine source categories) have emerged that compete
directly with existing synthetic rubber products. These
factors were based on information from several chemical
marketing reports and the International Institute of
Synthetic Rubber Producers (IISRP). While the EPA has been
made aware of plans to build a new EPR facility in the
United States, the EPA does not believe that the regulation
places EPR producers at an economic disadvantage.
Comment; One commenter (IV-D-4) stated that additional
epichlorohydrin data is currently being developed for a
title V permit application, and they would like EPA to
consider any significant new information that arises from
this effort (for Table 5-1, Baseline HAP Emissions).
Response: The information provided by the
epichlorohydrin facility in the original information
submittal was the basis for the MACT floor determination and
the estimation of impacts for the selected regulatory
alternative. While the commenter or any other person may
submit such data to the EPA after proposal, the EPA is not
obliged to use such information to redetermine the MACT
floor prior to promulgation. The EPA has a statutory
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obligation to promulgate MACT standards according to strict
deadlines. Were the EPA to continuously recalculate the
MACT floor base on each new item of data received prior to
promulgation, the promulgation of final standards would be
impossible. Such information may, however, be factored in
to any revision of the regulation pursuant to section
112(d)(6) of the Act.
Comment: One commenter (IV-D-8) voiced concern about
the economic impact of the proposed standards on styrene
butadiene latex manufacturing facilities, because these are
small facilities that cannot afford major capital
expenditures.
Response: In connection with the proposed regulation,
the EPA conducted an economic impact analysis (see docket
item (II-A-5). This analysis did not predict any serious
detrimental economic impacts on the styrene-butadiene latex
industry. Since the commenter did not provide any specific
comments on this analysis, the EPA concludes that its
analysis is correct.
2.6 DEFINITIONS
Following are comments regarding general definitions.
Throughout this document, other comments on definitions are
discussed with the section of the regulation to which the
definition pertains.
Comment: One commenter (IV-D-18) stated that one of
their experts thought the EPA's definition of "suspension
process" referred to a phase separation. Consequently, the
commenter recommends an alternate definition to eliminate
confusion.
Response: The definition of suspension process has
been modified in accordance with the suggestions of the
commenter. The definition in the final rule reads as
follows:
Suspension process means a process carried out with the
reactants in a state of suspension, typically achieved
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through the use of water and/or suspending agents
(e.g., polymerization reaction).
Comment: One coiranenter (IV-D-10) stated that the
definition of "process vent" differs between subpart F of
the HON and the proposed subpart U rule, and that these
should be made consistent. The commenter also stated that
it is unnecessary to define "continuous front-end process
vent," because each term in the phrase is already defined
elsewhere.
Another commenter (IV-D-18) claimed that the definition
of "process vent" should distinguish between solid, liquid,
and gas streams. He also indicated that the definition is
confusing with respect to whether a process vent originated
before or after control or recovery devices. This commenter
(IV-D-18) also states that there are differing definitions
of identical terms in Part 63, for example, the terms
"process vent" and "average flow rate." The commenter
suggested that the same definition of a term should be used
throughout part 63, and if a term needs redefining, it
should be redefined in and for the specific subpart where it
is needed.
Another commenter (IV-D-14) stated that the definitions
should be reconstructed so that the meaning of phrases or
terms are understood from the meaning of the individual
words that comprise the phrases. The commenter uses the
term "continuous process vent stream" as an example. The
commenter added that the proposed rule does not appear to
consistently address the difference between a vent and a
vent stream.
Response: The EPA reviewed the definition section of
the proposed rule, section 63.482, between proposal and
promulgation. As a result of this review, many definitions
were revised and clarified in the final rule. The EPA has
referred to subpart A, F, G, and H definitions in the final
rule when applicable, and has redefined terms that either do
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not share the same definition as in the other subparts, or
were not defined in a previous subpart. For easier
reference, the organization of terms referenced in subparts
A, F, G, and H was changed in the final rule/ referenced
terms are listed in alphabetical order with the subpart
where they are defined specified in parentheses after each
term.
The EPA has also reviewed and revised many definitions.
For example, the EPA has revised the definition of
"continuous process vent or continuous vent stream". The
revised definition combines the concepts of a physical
opening (i.e., the vent) and the emission stream. The
revised definition of "continuous front-end process vent" is
as follows:
Continuous front-end process vent means a point of
emission from a continuous unit operation within an
affected source having a gaseous emission stream with a
flow rate greater than or equal to 0.005 standard cubic
meter per minute and with a total organic HAP
concentration greater than or equal to 50 parts per
million by volume. Continuous front-end process vents
exclude relief valve discharges and leaks from
equipment regulated under §63.502.
This definition allows the use of one term throughout the
rule, which aids in clarifying the provisions.
The term "process vent" was also changed, and the new
definition is as follows:
Process vent means a point of emission from a unit
operation having a gaseous emission stream. Typical
process vents include condenser vents, dryer vents,
vacuum pumps, steam ejectors, and atmospheric vents
from reactors and other process vessels, but do not
include pressure relief valves.
The revised definitions distinguish that the stream is a gas
stream.
Comment: One commenter (IV-D-18) stated that the
proposed rule should incorporate by reference the definition
of "research and development facility" in the HON, as these
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facilities are exempted from the rule in section
63.480{d)(1).
Response•. The EPA intended for the HON term "research
and development facility" to apply to the subpart U proposed
rule, and this term has been incorporated into the final
rule.
Comment: One cotnmenter (IV-D-18) indicated that it
would be more accurate in the definition of "continuous
process" to state that it "approaches" steady-state.
Response: The EPA agrees with the cotnmenter and the
wording in the definition of "continuous process" has been
revised for the final rule.
2.7 MISCELLANEOUS
2.7.1 Storage Vessel Assignment to EPPU
Comment: One commenter (IV-D-18) recommended that the
EPA revise section 63.480 (f) (2) (i) (B) to indicate how to
assign storage vessels where the greatest input to/output
from is attributed to an off-site process, and it is also
used by two or more on-site processes.
Response: The final rule includes changes to address
the commenters concerns. Situations where off-site and on-
site process units use the same storage vessel are addressed
by 63.480(g)(3). Situations where multiple on-site process
units use the same storage vessel are addressed by section
63.480(g)(4) and (g)(5).
Comment: One commenter (IV-D-18) supported the EPA's
proposal to adopt storage vessel requirements from subpart G
for this rule. In addition, the commenter suggested that
the EPA should state in the preamble, that if a storage
vessel is already subject to another MACT standard,
compliance with that standard should constitute compliance
with this standard.
Response: The commenter is correct that the proposed
rule did not address this situation, and the final rule has
been changed to address the commenter's concern. Situations
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where a storage vessel may already be subject to another
MACT standard are addressed by section 63.480(g)(1), which
reads as follows:
If a storage vessel ir already subject to another
subpart of 40 CFR part 63 on [promulgation date], that
storage vessel shall belong to the process unit subject
to the other subpart.
Comment: One commenter (IV-D-18) supported the EPA's
proposal that storage vessels subject both to the subpart U
rule and to NSPS subpart Kb must comply with subpart U and
are exempt from subpart Kb.
Response: The commenter is correct that after the
compliance date of the final elastomers rule, a storage
vessel at an affected source that is also subject to 40 CFR
part 60, subpart Kb, is only required to comply with the
provisions of the final elastomers rule. This is stated in
section 63.481(i) of the final rule.
2.7.2 Relationship to Other Rules
Comment; One commenter (IV-D-18) supported the
inclusion of the table to describe which portions of the
General Provisions apply to subpart U affected sources.
However, another commenter (IV-D-17) indicated that there is
significant uncertainty regarding the applicability of
certain General Provisions to subpart U affected sources,
primarily due to the incorporation of HON requirements, and
conflicts between the HON and subpart U regarding which of
the General Provisions are incorporated. The commenter made
several recommendations designed to alleviate the confusion.
These include clarifying the effect of Table 3 of subpart F
on subpart U sources, revising Table 6 as appropriate,
and/or adding a provision to specify that subpart U sources
are subject only to the General Provisions requirements
specified in Table 6 of subpart U. Another commenter (IV-D-
10) stated that it is not clear which General Provisions
apply to subpart U affected sources, because of conflicts
between Table 6 of Subpart U and Table 3 of Subpart F. The
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commenter recommended that Table 3 not affect subpart U, and
that the requirements in Table 6 be reviewed closely.
Response: Table 6 in the proposed subpart U was
reviewed and revised between proposal and promulgation to
ensure consistency and clarity between the final elastomers
rule and the General Provisions. As requested by the
commenter, table 6 of subpart U now indicates that General
Provisions paragraphs which are reserved do not apply to the
elastomers rule. If these reserved paragraphs are replaced
with provisions at a later date, the EPA will make a
determination as to whether the provisions apply to the
elastomers rule. Paragraph (f) of section 63.481 has also
been revised to clarify that Table 3 of subpart F does not
apply to subpart U affected sources.
'Comment: One comment er (IV-D-5) requested that the
EPA provide additional applicability tables, indicating
which sections of the HON, subparts F, G, and H, do and do
not apply to the Polymers and Resins I NESHAP.
Response •. The EPA agrees that such tables would
eliminate confusion among affected sources and agencies
implementing the rule. Therefore, the EPA has added tables
cross-referencing sections of subparts F, G, and H that are
applicable to subpart U.
Comment: One cotnmenter (IV-D-18) indicated that the
word "replace," as used to identify changes to HON
requirements incorporated into the Polymers and Resins I
rule, may be interpreted by the Federal Register as an
instruction to amend the HON. The commenter suggested that
the EPA should either eliminate all use of the word
"replace," or otherwise ensure that inadvertent amendment
does not occur.
Response: The EPA does not intend for the HON rule to
be amended in any way as a result of the wording in the
elastomers rule. To reduce any chance of confusion, the EPA
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has used the words "shall apply" in place of the word
"replaces" when necessary in the final rule.
2.7.3 General
Comment: One commenter (IV-D-11) stated that the
Agency has moved their focus from performance based
standards to process issues which have no bearing on the
improvement of the environment. They add that raw
materials, types of catalysts, and equipment specifications
are the responsibility of the regulated community in meeting
the standards which protect the environment. The commenter
strongly recommended that the EPA consider the performance
basis in the formation of the standard for ethylene-
propylene rubber because many of the assumptions made and
promulgated in the HON will neither apply nor be successful
in reducing emissions from these sources.
Response: The EPA strongly disagrees with the
commenter's assertion that subpart U focuses on "process
issues which have no bearing on the improvement of the
environment." In fact, the EPA believes that this
regulation provides a great deal of flexibility to affected
sources in how they will comply. The only example from the
rule mentioned by the commenter is a vague reference to the
incorporation of the HON provisions.
All of the HON provisions incorporated directly, or by
reference, into subpart U are based on general process
stream characteristics. The EPA believes that this approach
does not in any way intrude into the process. While
reference control technologies are specified for streams
meeting the Group 1 criteria, the HON approach allows
flexibility in allowing the source to introduce unique
process modifications to change the stream characteristics
so that the stream is no longer Group 1. In no case does
the HON, or subpart U, specify or suggest process changes to
achieve these objectives.
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The EPA presumes that in addition to the HON
provisions, the commenter may be referring to the back-end
process provisions. While these provisions are written as
residual organic HAP limitations for the material entering
the back-end of the process, subpart U provides the
opportunity for affected sources to comply through process
changes (increased stripping effectiveness) or the use of
add-on control on selected back-end process vents. One of
the options for demonstrating compliance by stripping is by
monitoring the operating parameters of the stripper. While
this could be construed as dictating process operating
conditions, the EPA points out that this option was
incorporated into the rule at the direct request of
representatives of the elastomer industry.
Comment: Two commenters (IV-D-7 and IV-D-9) supported
the proposed rule, agreeing with the use of performance
standards, and find the standards reasonable. One commenter
(IV-D-7) stated that catalytic oxidation is an available
cost-effective control option that will allow sources to
comply with the standards, and the other commenter stated
that equipment for cost-effective control of organic HAP
from elastomer manufacturing is widely available.
Response •. The EPA agrees with the commenters, and has
retained the provisions referred to by the commenter in the
final rule.
Comment: Commenter IV-D-18 stated that section
63.480(g)(3)(ii)(B) should be revised to remove a redundant
phrase referring to "the Administrator's designee," because
the General Provisions already provides for delegation. In
addition, the commenter suggested a revision to clarify
which date applies, when referring to "upon initial startup"
or by 3 years after the compliance date. The commenter
suggested that the applicable date should be whichever comes
later.
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Response: The EPA agrees with the commenter and has
removed the phrase "or Administrator's designee, hereafter
referred to as Administrator," from the final rule. The
definition of "Administrator" as defined under subpart A is
applicable to this rule. The EPA also agrees with the
commenter's suggestion with regard to the compliance date
and has revised this paragraph accordingly.
Comment: One commenter (IV-D-8) stated that the SBL
source category should include only major sources, and
consequently only major sources should be used to calculate
the MACT floor. The commenter indicated that several
facilities assigned to the SBL source category and used to
calculate MACT floors may be area sources. The commenter
stated that the MACT floor should be modified if this is the
case.
Response: The determination of whether or not a
facility is a major source is a multi-stepped task. The
first step is to examine baseline emissions. The initial
baseline emission estimates for the styrene-butadiene latex
source category showed only three facilities with total HAP
emissions less than 25 tons per year (see docket item III-B-
2 or II-B-22). Therefore, these three provide the only
opportunity for area sources. The second step is to
determine if the facilities are located at plant sites that
are major sources. The EPA then retrieved actual emissions
data from the Toxic Release Inventory (TRI) for the entire
plant sites where styrene butadiene latex operations are
located (see docket item IV-B-1). When the EPA reviewed
this data, it determined that each of the three facilities
with estimated HAP emissions less than 25 tons per year were
located at plant site with reported emissions of HAP in TRI
greater than 25 tons per year. Therefore, the EPA concluded
that all styrene-butadiene latex facilities were major
sources, or were located at major source plant sites. Due
to this conclusion, the EPA maintains that the MACT floor
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for SBL was properly determined. The EPA would point out
that each facility had the opportunity to review and comment
on their baseline emissions in late 1993.
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3.0 STORAGE VESSELS
Several comments were received on the storage tank
provisions. The EPA noted a misinterpretation of the
proposed regulation that occurred several times in the
comments related to the distinction between a storage vessel
and a surge control vessel. The definition of surge control
vessel is as follows:
Surge control vessel means feed drums,
recycle drums, and intermediate vessels. Surge
control vessels are used within an elastomer
product process unit when in-process storage,
mixing, or management of flow rates or volumes is
needed on a recurring or ongoing basis to assist
in production of a product.
The definition of storage vessel states that a surge control
vessel is not a storage vessel.
Storage vessels are subject to the provisions of
sections 63.119 through 63.123 of subpart G by reference in
section 63.484 of subpart U. Surge control vessels are
subject to section 63.170 of subpart H by reference in
section 63.502 of subpart U. While the criteria to
determine whether controls are required are identical for
storage vessels and surge control vessels, there are
differences in the available reference control technologies.
Storage vessels may be controlled using internal or external
floating roofs or closed vent systems and control devices
achieving 95 percent emission reduction. The only
acceptable control technology for surge control vessels is a
closed vent system and control device.
The EPA determined that many of the comments received
on "storage vessels" were in fact referring to vessels that
fall under the definition of surge control vessel. One
example is vessels following the reactor that contain
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intermediate latex or other elastomer product. The EPA
suggests that owners and operators of facilities subject to
subpart U pay careful attention to these definitions.
3.1 APPLICABILITY REQUIREMENTS
Comment: One commenter (IV-D-26) stated that the EPA
should conduct a full floor analysis for new and existing
storage vessels, considering each chemical and the various
sizes of tanks for each subcategory.
Response: The commenter seems to be suggesting that
the EPA conduct floor analyses for each HAP stored at
elastomer production facilities, and set HAP-specific
requirements based on the results of these analyses. The
EPA rejects such an approach for two basic reasons. First,
consideration of individual HAP storage vessel controls
would not be representative of facility-wide storage vessel
control levels. Second, owners and operators of elastomer
production facilities would need a test method to determine
the compliance requirements for new HAP that may be used in
the future.
However, the EPA believes that it is reasonable to
exempt a storage vessels from the regulation when it is
clear that the vessel would never be a Group l vessel.
Therefore, this comment did result in an analysis by the EPA
to determine specific HAP used in the elastomer industry
with low enough vapor pressures that vessels storing these
HAP would never be Group 1. Three such HAP were identified:
acrylamide, epichlorohydrin, and styrene. Therefore, in
paragraph (b) of section 63.484, the final rule exempts
storage vessels containing these HAP at existing sources.
This exemption is also extended to surge control vessels and
bottoms receivers at existing sources.
Comment: One commenter (IV-D-14) agreed with the
proposal that storage vessels containing organic HAP only as
impurities should not be considered emission points at the
affected source. However, the commenter indicated that this
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concept should be expanded to apply to vessels whether the
materials they store are liquid or not, and where HAP is
present at undetectable levels. Two other commenters (IV-D-
10 and IV-D-16) stated that the EPA should define a specific
percentage of organic HAP content below which storage
vessels would be exempt from regulation, rather than using
the term "impurities." The commenters suggested that a value
of 5 percent would be appropriate for consistency with the
HON, and that section 63.480(c)(5) should be revised
accordingly.
Response: The EPA believes that the commenter's
requests are reasonable and has expanded the provisions
contained in proposed section 63.480(c), which may be found
in section 63.480(c)(5) of the final rule, and in the
definition of storage vessel in section 63.482, according to
the commenters' suggestions. The provisions now read as
follows:
Vessels and equipment storing and/or handling material
that contains no organic HAP, no detectable.organic
HAP, and/or organic HAP as impurities only.
However, the EPA does not believe that a cutoff value of 5
percent is appropriate to determine applicability of the
storage vessel provisions, because it does not take into
account the volatility of the HAP being stored. The EPA
also would point out that the storage vessel provisions in
subpart U are based on the HON, and remain basically
consistent with the HON provisions.
Comment: Four commenters (IV-D-5, IV-D-8, IV-D-10, and
IV-D-18) supported the exemption of stripped latex storage
tanks from control requirements. However, three of these
commenters (IV-D-5, IV-D-8, and IV-D-10) stated that high
conversion SBR or polybutadiene latex storage tanks should
also be exempt. Specifically, they recommended that
storage tanks used for latex containing less than 5 percent
organic HAP should be exempted. The commenters based this
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statement on the following reasons: (1) control of high
conversion latex tanks does not represent the MACT floor,-
(2) emissions from these tanks are insignificant (the
commenter provides data on page 5, indicating less than 2.5%
styrene); (3) control would require conversion of all
atmospheric tanks to pressurized tanks and installation of a
vent header and control device; (4) the cost per ton of
control would be uneconomical; and (5) a cutoff at 5% HAP
would be consistent with subpart H requirements.
Response: The rationale provided by the commenters for
including a 5 percent organic HAP cutoff for latex storage
vessels is quite flawed. First, the proposed rule did not
require that high conversion latex storage vessels be
controlled, but rather that the group determination be made
for the storage vessel, and that Group 1 storage vessels be
controlled. Based on the information on styrene
concentration in latex provided by the commenters, it was
determined that a high conversion latex storage vessel would
never exceed the vapor pressure cutoff for a Group 1 storage
vessel. Therefore, the proposed storage tank provisions
(i.e., the HON level of control) would not require any
control for these vessels. The EPA believes that a
demonstration of the concentration of HAP in the storage
vessel would not be considerably less burdensome than the
determination of organic HAP vapor pressure.
While the EPA does not agree with the argument raised
by the commenter, the analysis of this issue led the EPA to
other conclusions. The EPA is convinced that an SBL storage
vessel (high conversion or otherwise) would never contain
sufficient HAP to exceed the vapor pressure cutoff for
Group 1 storage vessels. This is primarily due to the low
vapor pressure of styrene. Therefore, to avoid unnecessary
recordkeeping and reporting costs, the EPA concluded that it
was reasonable to exempt all SBL storage vessels from the
requirements of section 63.484. In addition, the EPA
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believes the same criteria applies to surge control vessels
and bottoms receivers containing SBL. Therefore, similar
exceptions were added to section 63.502.
Comment: One commenter (IV-D-18) stated that based on
Table 7 of the preamble, the proposed rule will achieve no
reductions in HAP emissions from storage vessels in
styrene-butadiene latex process units. However, this
differs from the Basis & Purpose Document, which indicates
that 6 of 15 facilities are below the floor, which is the
HON level of control. If this is the case, the rule would
be expected to achieve emission reductions. If not, the
commenter recommended that these storage vessels be exempted
from the regulations in order to eliminate the reporting and
monitoring burden.
Response: The EPA recognizes the inconsistencies that
existed in the descriptions of the MACT floor and impacts
analyses. Of the two analyses, the impacts analysis was
correct. The six facilities that were reported to be
controlled at a level less than the HON in the MACT floor
analysis were so classified because a HAP with a vapor
pressure greater than the Group l cutoff was stored in fixed
roof uncontrolled tanks at these facilities. However, upon
further investigation, it was determined that these storage
vessels did not meet the Group 1 capacity requirements.
This discovery was not reflected in the MACT floor analysis.
However, the EPA maintains that this would not change the
determination of the MACT floor.
The EPA disagrees with the suggestion that storage
vessels at SBL facilities should be exempted simply based on
the fact that no impacts were predicted for the subcategory.
As noted above, there were HAP used at SBL facilities with
vapor pressures high enough to be considered Group 1 storage
vessels, meaning that it is not possible to exempt SBL
facilities from all storage requirements. However, as
discussed elsewhere in this section, the EPA did determine
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that certain storage (and surge control) vessel exemptions
were warranted.
Comment: One commenter (IV-D-12) stated that tanks
downstream of EPR stripping operations should be exempt from
storage vessel requirements, just as those containing latex
downstream of stripping operations are exempt. The
commenter stated that in EPR manufacturing, tanks holding a
crumb rubber slurry are downstream of the sampling point
(point of compliance). Therefore, if the emission standard
has been met, these downstream tanks should be exempt from
regulation.
Response: The EPA agrees with the commenter that
storage vessels downstream of stripping operations at
ethylene-propylene rubber facilities that are in compliance
with the provisions of section 63.494 [old section 63.487-1]
through the use of stripping technology should be exempt
from the storage vessel requirements. The EPA also believes
that surge control vessels and bottoms receivers (the
vessels referred to by the commenter are actually surge
control vessels and not storage vessels) located downstream
of the stripping operations should also be exempt from the
provisions of section 63.502. Further, the EPA believes
that these exemptions should also extend to the other
subcategories required to comply with the residual organic
HAP limitations in section 63.494 [old section 63.487-1]
(a)(i)-(3). However, since the residual organic HAP content
of rubber leaving the stripping operations at ethylene
propylene rubber and polybutadiene/ styrene-butadiene rubber
by solution facilities complying with these provisions
through the use of add-on control is not restricted, these
exemptions are not available to these facilities.
3.2 SELECTION OF EMISSION LIMITS
Comment: One commenter (IV-D-4) stated that the
proposed regulation may require the installation of a
floating roof or control device on their tanks containing
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unstripped nitrile butadiene latex. The commenter stated
that floating roofs would not be feasible for most of these
tanks, and installing a new control device would be a
significant investment for relatively small emission
reductions.
Response: The EPA rejects the argument that the
regulation should exempt unstripped nitrile butadiene latex
based on the assertions that floating roofs are not feasible
and that installing a new control device would be a
significant investment. First, the vessels described by the
commenter are surge control vessels, and not storage
vessels. Therefore, floating roofs are not a control
option. Second, the EPA believes that if the surge control
vessel meets the requirements for control in Tables 3 and 4
of subpart H, which are based on the emission potential of
the vessel, then controls are cost-effective.
Comment: One commenter (IV-D-17) stated that the
prescribed control efficiency calculation procedure does not
accurately reflect the efficiency of the closed vent to
control device system, which may include control components
in series. The commenter used the fixed roof and closed
vent to a control device control option in conjunction with
vapor balancing between vessels upstream of the control
device to enhance overall system efficiency. He indicated
that the calculation in section 63.120(d)(1) accounts only
for the end of pipe control efficiency, not that of the
entire control system. The commenter requested that a new
provision be added to section 63.484, as paragraph (o), in
which the control efficiency of a closed vent system using
vapor balancing would be calculated based on the "overall
efficiency of the vapor balance system and control device."
Response: It should first be pointed out that the
vessels described by commenter IV-D-17 are, by definition,
surge control vessels, and not storage vessels. Therefore,
these vessels are not subject to the requirements in section
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63.119 through section 63.123, but are subject to the
provisions in section 63.170. The EPA assumes that the
vessels meet the criteria in table 2 of subpart H.
Therefore, according to section 63.170, these vessels "shall
be equipped with a closed vent system that routes the
organic vapors vented from the vessel back to the process or
to a control device that complies with the requirements in
section 63.172 of this subpart, except as provided in
section 63.162(b) of this subpart."
The EPA agrees that it is reasonable to consider the
overall effectiveness of a control "system" in determining
compliance with the rule, and that such systems that have
been demonstrated to be equivalent to the reference control
technology should be allowed. While the EPA believes that
the system described by the commenter could be demonstrated
to be equivalent to the reference control technology for
surge control vessels, the commenter did not provide
sufficient documentation to allow a complete evaluation of
equivalence.
The EPA believes that facilities should have the
opportunity to utilize control techniques that are
equivalent to the reference control technologies, provided
that the owner or operator demonstrates the equivalency to
the Administrator. The EPA maintains that subpart U, as
proposed, already provided the opportunity for the
commenter, as well as other elastomer production facilities,
to demonstrate equivalency of alternative control
techniques.
Section 63.177 of subpart H addresses the procedures to
obtain approval of alternative means of emission
limitations. In summary, this section specifies that the
owner or operator must submit documentation of the
equivalency determination to the Administrator.
Comment: One commenter (IV-D-12) suggested that
provisions be included in the standard to allow alternative
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control strategies, by stressing performance rather than
particular equipment. The commenter's EPR solvent storage
tanks employ alternative emission control methods, which
have been demonstrated to reduce emissions. The commenter
has submitted confidential material outlining their control
strategy, which meets Group 1 standards. They requested
that the EPA review this strategy and allow alternative
control strategies.
Response: This commenter is referring to a vessel that
is a storage vessel by definition. While the previous
response addressed alternative controls for surge control
vessels, the same basic logic applies here as well. The EPA
agrees that a facility should have the opportunity to use
control systems that are equivalent to the reference control
technologies for storage vessels in section 63.119 of
subpart G. The EPA also believes that the mechanism for
obtaining approval to use alternative storage tank controls
is provided in section 63.121.
3.3 ASSOCIATED DEFINITIONS
Comment: Two commenters (IV-D-5 and IV-D-8) stated
that a definition for "high conversion latex" should be
added to the rule. The commenters recommended that a high
conversion latex be defined as one where monomers are
reacted to at least 95 percent conversion.
Response: As discussed above, the EPA has decided that
the exemption of storage vessels, surge control vessels, and
bottoms receivers containing high-conversion styrene-
butadiene and nitrile-butadiene latex is appropriate.
Therefore, a definition of high-conversion latex is needed.
The EPA used the suggestion of the commenters to define
high-conversion latex as latex where the monomers are
reacted to at least 95 percent conversion.
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3.4 MISCELLANEOUS
Comment; One cotnmenter (IV-D-26) stated that the EPA
should re-evaluate cost-effectiveness for floating roofs and
refrigerated condensers. The commenter stated that the EPA
erred in costing floating roofs. Vendor information and
graphs of capital costs for storage vessels were attached to
the comment. Another commenter (IV-D-10) claimed that the
EPA has not demonstrated that the storage vessel vapor
pressure applicability thresholds are cost-effective. The
commenter stated that the HON storage vessels provisions
incorporated into subpart U relied on floating roof
technology that is considered to be unsafe for elastomer
product processes. The commenter stated that most storage
vessels containing HAP are controlled by routing emissions
to condensers, and these systems reduce emissions through
vapor balancing by maintaining a constant level in the tanks
during operations. According to the commenter, floating
roof technology appropriate for upstream elastomer storage
costs twice as much as that required in the HON.' The
commenter also suggested that section 63.484 should refer to
"storage vessel systems" when referencing subpart G.
Response: Commenters challenged the validity of the
costs for internal floating roofs used for the HON storage
vessel analysis. They stated that the costs used for the
HON were low, and that current modern roofs cost about twice
as much to install. However, cost data for internal
floating roofs were not provided by the commenter to support
these claims. Data available to the EPA showed that the HON
costs for internal floating roofs were higher than costs
included in the recent Alternative Control Technology (ACT)
document entitled "Alternative Control Technology Document:
Volatile Organic Liquid Storage in Floating and Fixed Roof
Tanks" (EPA-453/R-94-001; January 1994) prepared by the EPA.
For installation of a 40,000 gallon capacity storage vessel,
capital costs were approximately the same, and for larger
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storage vessels, costs based on the HON procedures were
higher than costs based on the ACT procedures. This
comparison is available in the docket as part of a
memorandum entitled "HON/CTG Cost Comparison for Internal
and External Floating Roof Tanks," which is contained in
subcategory IV-B of Docket No. A-92-45.
The commenter (IV-D-26) provided the results of a cost-
effectiveness analysis for control of one 40,000 gallon
capacity storage vessel using a refrigerated condenser.
Based on this one analysis, the commenter felt that the
vapor pressure applicability criteria for large storage
vessels should be 13.0 psia. The EPA selected the vapor
pressure applicability criteria for the HON to be
representative of the average cost effectiveness for
controlling all storage vessels within the greater than
40,000 gallon capacity size range. In general, it is more
cost effective to control larger storage vessels also
covered by this applicability criteria. Therefore, the EPA
has not changed the vapor pressure applicability for large
storage vessels.
In addition, the commenters that were concerned about
being required to install floating roofs should be aware
that the storage vessel provisions of the final rule do not
specify the controls that are to be applied (i.e., internal
floating roofs are not required) when control is required.
The Reference Control Technology (RCT) for storage vessels
is any of the options listed in the storage vessel
provisions (section 63.119).
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4.0 CONTINUOUS FRONT-END PROCESS VENTS
4.1 APPLICABILITY REQUIREMENTS
Comment;: Several coiranenters (IV-D-10, IV-D-12, IV-D-
16, IV-D-17) stated that the exemption from halide controls
for butyl/halobutyl production should be extended to all
rubber manufacturers, since halogen-containing compounds or
by-products have historically been routed to flares. One
commenter (IV-D-17) supported the exemption for butyl and
halobutyl rubber, and claimed that to control hydrogen
halides and halogen emissions with combustion with a
scrubber is above the MACT floor and not cost-effective.
This commenter noted that the current combustion control
without scrubbing is MACT for existing sources and that no
additional control is required. One commenter (IV-D-16)
stated simply that the exemption in section 63.485(m) for
butyl/halobutyl rubber halogenated process vents should be
extended to EPR manufacturers, if the vent stream was
controlled by a combustion device prior to June 12, 1995.
Response: Only one existing facility was identified in
each the halobutyl and the butyl rubber subcategories. At
both of these facilities, halogenated vent streams were
vented to a flare and/or boiler. Since both of these
subcategories were single-facility subcategories, the MACT
floor was determined to be the existing level of control.
The EPA examined the impacts of requiring halogenated vent
streams at the halobutyl and butyl rubber facilities to
comply with the proposed requirements for all other
elastomer subcategories (i.e, the HON-level of control).
The EPA concluded that the costs associated with this level
of control were not reasonable, given the associated
emission reduction. Therefore, the proposed regulation
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allowed halogenated streams at halobutyl and butyl rubber
facilities that were routed to a flare or boiler prior to
proposal to continued to be controlled with these combustion
devices, without additional control for the resulting
halides.
Prior to proposal, the EPA was aware of one EPR
facility - Exxon in Baton Rouge, Louisiana - that also
routed a halogenated vent stream to a boiler. However,
since only one of five EPR facilities reported this
situation, the EPA concluded that this level of control was
not the MACT floor for EPR. Other EPR producers claimed
that they also had halogenated streams at their facilities,
but none offered any information to quantify the amount of
halogens in the stream to determine if the streams could be
classified as halogenated.
In response to this comment, the EPA held discussions
with this producer, along with three of the four remaining
EPR producers. The EPA learned from these conversations
that the chlorinated organic compounds are present in
streams at all of the EPR facilities. These compounds are a
by-product of the polymerization reaction, resulting from a
chlorinated catalyst. At all four of the facilities
contacted, the streams containing the chlorinated compounds
are routed to either a flare or boiler. The remaining
questions were whether the streams were Group 1 and
contained sufficient halide levels to be considered
halogenated streams, meaning that they would have to be
routed to an incinerator, followed by a scrubber. Due to
the widely varying concentration in the stream, all
facilities indicated that it was difficult, if not
impossible, to accurately determine the halogen levels.
However, all expressed confidence that at times, the 0.45
kg/hr halide threshold was exceeded.
The EPA concluded that at four of the five EPR
facilities, it is reasonable to believe that halogenated
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streams are routed to either a boiler or flare. Therefore,
the floor for EPR is the existing level of control for these
halogenated vent streams. In addition, as with halobutyl
and butyl rubber, the EPA does not believe that it would be
cost-effective to require new incinerators and scrubbers to
be installed at these facilities, when the only net emission
reduction would be the reduction of the hydrogen chloride.
However, as noted above, sufficient stream-specific
information was not available to conduct this analysis.
Therefore, the final rule has been changed to extend the
exemption for existing halogenated streams routed to a
boiler or flare to EPR producers.
Comment: Commenter IV-D-23 requested that the EPA
require new sources producing Butyl and Halobutyl Rubber to
control hydrogen halides and halogens by installing an
incinerator and scrubber system, in order to be consistent
with existing State requirements. The commenter agrees that
such requirements for existing sources would not be cost-
effective.
Response: The EPA agrees that the exemption for butyl
rubber and halobutyl rubber halogenated vent streams vented
to a flare or boiler prior to June 12, 1995, should only be
available to existing sources. While the EPA believes that
the proposed rule would only allow this exemption at
existing sources, the EPA has made a minor change to the
final rule to ensure that this is clear.
4.2 SELECTION OF EMISSION LIMITS
Comment: One commenter (IV-D-19) voiced concern that
section 63.485 does not include provisions for front-end
vent streams controlled by an internal combustion engine.
The commenter suggested that 63.485 be revised to amend
63.116(b)(2) to also exempt from performance test
requirements a vent stream routed to an internal combustion
engine as primary fuel. The commenter also suggested that
monitoring the on/off status of the internal combustion
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engine would provide a means of demonstrating compliance
with these control requirements.
Response: Upon further investigation of this issue
with the commenter, the EPA agrees that control of emissions
by an internal combustion engine is equivalent to the other
control methods provided in the rule. Therefore, section
63.485 has been changed to allow the use of internal
combustion engines, and to exempt these devices from the
testing requirements.
Comment •. One commenter (IV-D-4) stated that the
assumption, in the absence of vent stream characteristics
before the flare, that the flare control level was equal to
the HON/ACT, could lead to a standard higher than the
existing level of performance. The commenter would like to
provide more input to the EPA on this issue.
Response: The EPA believes that a flare, properly
operated in accordance with the provisions of section
63.11(b) (General Provisions) achieves an emission reduction
of at least 98 percent. Therefore, the EPA believes it is
appropriate to consider the control level of a flare to be
equal to the HON/ACT level of control.
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5.0 BATCH FRONT-END PROCESS VENTS
5.1 BASIS FOR THE STANDARD
Comment: Several commenters (IV-D-5, IV-D-8, IV-D-10)
disagreed with the EPA's reliance on the Batch Processes ACT
document, claiming that it was not appropriate to the
elastomer manufacturing industry. These commenters stated
that the standards for batch process vents are inappropriate
and unnecessarily burdensome. One commenter (IV-D-5)
claimed that basing these standards on the Batch Processes
ACT document fails to recognize that in rubber
manufacturing, equipment is not opened during processing
because butadiene is a gas at atmospheric pressure. Thus,
all charging is done under vacuum, or under pressure, and
when the reaction is complete, removal of material is done
in a similar manner. This commenter requests that SBR, PER,
and NBR processes be exempted from the batch process vent
requirements.
Response: The EPA strongly disagrees with the
commenters regarding the use of the Batch Processes
Alternative Control Techniques (Batch ACT) document in the
establishment of requirements for the elastomer industry.
The Batch ACT was developed by the EPA as guidance to State
and local air pollution agencies in the determination of
appropriate control levels for batch processes.
In the development of the batch front-end process
provisions of subpart U, only one segment of the Batch ACT
was used - the process vent applicability criteria. These
criteria are based on generic process vent parameters (flow
rate, emissions, and volatility of the organic HAP in the
stream), and are applicable without regard to the type of
process producing the stream. The application of these
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criteria were compared to the existing levels of control in
the elastomer industry, and it was determined that the floor
level of control- was consistent with the 90 percent level of
control described in the Batch ACT. The subpart U
monitoring, recordkeeping, and reporting provisions
associated with batch front-end process vents were developed
for the elastomers rule and were not from the Batch ACT.
Therefore, the EPA did not feel it was necessary to
reconsider the reliance on the Batch ACT in the development
of subpart U.
The EPA appreciates the argument raised by the
commenters related to butadiene. However, the EPA would
point out that under the situations described by the
commenters, there is unlikely to be a vent to the atmosphere
that would be subject to the batch vent provisions.
Further, butadiene is not the only HAP used in these
processes (with the possible exception of PBR) , and the most.
common other HAP used - styrene and acrylonitrile - are not.
gases at atmospheric pressure, meaning that front-end
process vents downstream from the reactor may have the
potential for HAP emissions. Therefore, the EPA does not
agree that these processes should be exempted from the batch.
front-end process vent provisions.
Comment -. One commenter (IV-D-10) suggested that at a
minimum, the EPA should simplify and clarify the
requirements of section 63.486-1. Another commenter
(IV-D-18) stated that, in general, the batch process vent
provisions are difficult to understand, and he recommended
conducting workshops to try and develop simpler language.
Another commenter (IV-D-18) supported the approach in the
proposed rule that allows the applicability of batch
front-end process vent requirements to be determined on an
individual vent basis.
Response: The EPA maintains that HAP emissions from
process vents are quite complicated to determine, and that
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regulations addressing the control of these emissions will,
out of necessity, be intricate. However, the EPA believes
that the potential for HAP emissions from batch operations
at elastomer production facilities warrant control. In
response to comments, measures have been taken to simplify
these provisions in the final rule. Many of these changes
are discussed below. The approach that bases applicability
on an individual vent basis, which was a simplifying aspect
of the proposed rule, has been maintained in the final rule.
5.2 APPLICABILITY REQUIREMENTS
5.2.1 Group Determination
Comment: Several commenters (IV-D-18, IV-D-25, IV-G-2)
submitted comments on the threshold levels for low, medium,
and high volatility streams. Two of the commenters (IV-D-25
and IV-G-2) stated that the levels are too high, and will
result in inadequate control. One commenter (IV-G-2) stated
that, for example, the threshold for low volatility vents
would permit an hourly HAP emission rate of 13 pounds per
hour, with an annual operating schedule of 2,000'hours per
year, and this is a large emission rate to be exempt from
control, especially for HAP. This commenter suggested that
this level should be significantly reduced to be at least as
stringent as the thresholds for RACT (a process vent with an
emission rate between 0.5 and 3.5 Ibs/hr would require
control). The commenter added that an increase in the cost
of control would be justified and appropriate for an
increase of control for the pollutants regulated by this
rule, which are known or suspected carcinogens. The third
commenter (IV-D-18) stated the kilogram threshold levels for
low, moderate, and high-volatility streams are confusing
because they do not follow any consistent trend. Further,
the commenter stated that the numbers are so close that it
would seem more appropriate for the EPA to select a single
number. This commenter recommended that the EPA either pick
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one of the numbers, or pick the average, and establish that
as the threshold for all levels of volatility.
Response: The Batch Processes ACT developed an annual
threshold emission level for each of the three volatility
classes. The different values reflect the use of two
different control devices (i.e., condensers and thermal
incinerators) in the development of the Batch Processes ACT
control level options. Given this, the EPA initially judged
that selection of a single annual threshold emission level
would not be appropriate and included all three levels in
the proposed standards. However, upon further review, the
EPA has found that no adverse impact will result from the
use of a single annual threshold emission level and, indeed,
the final standards have been significantly simplified. In
addition to removing the requirement to determine the
volatility class, the final standards contain only one
equation for determining the cutoff flow rate [new section
63.488 (f)] which is the last step in the group determination
process. Therefore, the final standards contain'a single
annual threshold emission level.
Comment: A commenter on the proposed Polymers and
Resins IV regulation (docket number A-92-45, item IV-D-9),
suggested changing the batch vent group determination
provisions to only utilize emissions data from an EPPU's
primary product.
Response: This comment was received on subpart V, and
the EPA determined that a change was necessary, as discussed
below. Since the proposed batch vent provisions were
similar between subpart U and V, the EPA decided that this
change was also appropriate for subpart U.
The EPA has considered the request to perform the group
determination on the primary product and agrees that this
would provide acceptable results from an environmental
perspective while simplifying the compliance requirements
for and improving the enforceability of the batch front-end
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process vent standards. The final standards contain
provisions allowing the owner or operator of an affected
source to perform the group determination for batch front-
end process vents based on annualized production of a single
batch unit operation. However, the EPA does not consider it
to be appropriate from an environmental prospective to allow
anything other than the worst-case HAP emitting batch unit
operation to be considered when basing applicability on a
single product (i.e., batch unit operation). Therefore, the
final standards specify that the worst-case HAP emitting
batch unit operation be used when an owner or operator
chooses to annualize a single batch unit operation for
purposes of determining applicability. The final standards
define the worst-case HAP emitting batch unit operation and
describe how emissions are to be annualized to represent
full-time production; full-time production does not
necessarily mean operating at maximum production rate. As
described above, the EPA has modified the final standards to
address the commenter's concern.
Comment: One commenter (IV-D-26) stated that the
inclusion of uncontrolled emissions before a recovery device
is arbitrary and capricious, and contrary to pollution
prevention principles. The commenter stated that
uncontrolled emissions must be calculated after any recovery
device. Another commenter (IV-D-14) disagreed with
paragraph 63.486-2(a)(1) which states that only three types
of condensers are considered part of the unit operation and
not recovery devices. The commenter noted that other types
of recovery devices can operate as part of the unit
operation without increasing the emissions rate to the
atmosphere, and that these should be allowed. The commenter
suggested adding the phrase "In addition to other equipment"
to the second sentence in that paragraph.
Response •. The EPA is aware that the group
determination procedures for batch and continuous front-end
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process vents are different. This is a direct result of the
analyses that developed control requirements for batch and
continuous front-end process vents. Given the differences
between batch and continuous front-end process vents and the
fact that control requirements were based on different
analyses, the EPA does not find differences in the group
determination procedures objectionable. Further, the
analysis that developed control requirements for batch
front-end process vents (i.e., Batch Processes ACT) was
based on applying controls prior to recovery or control
devices. Therefore, the EPA does believe it is necessary to
revise this analysis based on the comments brought forth.
The final rule retains the requirement to make group
determinations for batch front-end process vents prior to
recovery or control devices.
Comment: One commenter (IV-D-14) stated that the
provision only allowing emissions to be estimated when test
methods can be shown to be inappropriate is overly
restrictive. Instead, the commenter requested that if
emissions can be estimated based on engineering practices,
an affected source be allowed to use emission estimates
without having to demonstrate that the test methods are not
appropriate.
One commenter (IV-D-18) supported the use of
engineering assessments to determine values required in the
regulation; however, the commenter added that it is
unreasonable to require a demonstration that other methods
are inappropriate before allowing these engineering
assessments. Instead, the commenter recommended that the
EPA follow the HON, by allowing engineering assessments as
long as their basis is documented.
Response: Several commenters requested that the final
standards allow the owner or operator to select among the
three techniques for estimating emissions provided in the
proposed standards (i.e., remove the hierarchial
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organization for using the techniques included in the
proposed standards). The EPA believes the data required to
use the emissions estimation equations should be obtainable
with reasonable effort. Further, specific comments
regarding the accuracy or inappropriateness of the equations
were not made. Given this, the EPA favors a more consistent
estimation technique which is provided by the use of the
emissions estimation equations. The final standard will
continue to require the use of the emissions estimation
equations, unless the owner or operator can demonstrate that
these equations are inappropriate.
However, independent of the comments provided, the EPA
has concluded that direct measurement of emissions may prove
to be difficult and may or may not provide an increased
assurance of accuracy over the use of engineering
assessment. Therefore, if an owner or operator can
demonstrate that the emissions estimation equations in
section 63.488 [old section 63.486-2] (b)(1) through (4) are
not appropriate, the final standards allow the selection of
either direct measurement or engineering assessment.
Further, criteria for demonstrating that the emissions
estimation equations are not appropriate to a specific batch
emissions episode have been added to the final standards.
These criteria require either: 1) the availability of test
data that demonstrate a greater than 20 percent discrepancy
between the test value and the estimated value, or 2) that
the owner or operator demonstrate to the Administrator
through any other means that the emissions estimation
equations are not appropriate for a given batch emissions
episode.
Comment: One commenter (IV-D-26) supported excluding
flare-controlled operations from the group determination
calculation procedure in section 63.486-2.
Response: This provision has been retained in the
final rule.
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5.2.2 Other Applicability Issues
Comment: One commenter (IV-D-18) stated that the EPA
must clarify that fugitive emissions do not disqualify batch
vent streams combined with continuous vent streams from the
exemption from regulation in section 63.486-l(e), which
requires that there be no emissions to the atmosphere to
qualify.
Response: The EPA did not intend that negligible
emissions from well maintained piping or ductwork would
disqualify a batch front-end process vent from this
exemption. The final rule has been clarified to represent
the EPA's original intention. Specifically, section 63.486-
l(e)(2) has been revised, so that it no longer requires "no
emissions to the atmosphere," but, rather, specifies that
"the only emissions to the atmosphere from the batch front-
end process vent or aggregate batch vent stream prior to
being combined with the continuous front-end process vent
are from equipment subject to and in compliance with section
63.502."
Comment: One commenter (IV-D-18) suggested that the
wording of 63.486-2(h)(1)(i) be revised so that it does not
imply that literally no halogens or hydrogen halides must be
present in the entire process, for an owner or operator to
determine that a batch process vent is not halogenated. The
commenter stated that trace amounts of halogens or hydrogen
halides may be present in portions of the process without
leading to a halogenated vent stream determination.
Response: The commenter requested that EPA clarify the
exemption in section 63.486-2(h)(1)(i) to account for
halogens or hydrogen halides present in the process in
negligible amounts. In the final rule, this paragraph
[63.488(h)(1)(i)] has been added to as follows: "Halogens
or hydrogen halides that are unintentionally introduced into
the process shall not be considered in making a finding that
a batch emission episode is nonhalogenated." The added
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language does not use the phrase "as an impurity" since
impurity is defined in the rule. Additionally, the added
language does not quantify a de minimis amount of
intentionally introduced halogens or hydrogen halides (i.e.,
present as an impurity in a raw material) because section
63.488 [old section 63.486-2] (h) (1) (ii), engineering
assessments, can be used to accommodate these situations.
The same commenter requested that an owner or operator
be allowed to use process knowledge that halogens or
hydrogen halides cannot enter a specific batch process vent,
even though they are present in the process, to determine
that a batch emission episode is not halogenated. This type
of determination falls under section 63.488 [old section
63.486-2] (h) (1) (ii) , engineering assessment of the final
rule and is allowed.
5.3 EMISSION LIMITS
Comment: One commenter (IV-D-10) said that the
requirement for Group 2 batch front-end process vents to
comply with the batch cycle limitations in paragraph
63.486-1(g) is unduly burdensome and will be very costly to
implement. The commenter recommended that section
63.486-2(d)(4), which contains this requirement, be deleted
from the rule.
Response: Group 2 continuous front-end process vents
are required to report process changes that affect the total
resource effectiveness (TRE) index such that it either
becomes less than 4.0 or becomes less than 1.0 (i.e.,
becomes a Group 1 vent). In addition, vents with TREs
between 1.0 and 4.0 are required to perform continuous
monitoring to ensure that they remain Group 2. The EPA
examined comparable means of ensuring that Group 2 batch
front-end process vents did not become Group 1 without
proper notification and subsequent control.
The batch front-end process vent provisions do include
the requirement that process changes must be reported.
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However, the EPA realized that one of the actions that could
cause a Group 2 batch front-end process vent to become Group
1 is the processing of more batches, which would not
normally be considered a process change. In addition, the
EPA considered requiring continuous monitoring for those
batch front-end process vents that were "nearly" Group l,
but concluded that such monitoring would be too burdensome
for batch process vents. Therefore, the EPA devised the
batch cycle limitation concept to track the effect of
increasing production on the group status of a batch front-
end process vent.
As was pointed out at proposal (60 FR 30808), "the
batch cycle production limitation does not limit production
to any previous production level, but is based on the number
of cycles necessary to exceed one of the two batch front-end
process vent applicability criteria." The rule simply
requires that an owner or operator track the number of
batches processed in a front-end batch unit operation. The
EPA believes that such records are undoubtedly already
maintained at elastomer production facilities, and that
little additional burden is created by the requirement to
keep such production records for comparison with the batch
cycle limitation. Therefore, the EPA generally disagrees
with the commenter's assertion that the batch cycle
limitations are unduly burdensome.
The EPA does recognize, however, that one aspect of the
proposed provisions related to batch cycle limitations might
be burdensome, which is the requirement for quarterly
submittal of the number of batch cycles performed.
Therefore, this requirement has been deleted from the final
rule, and the owner or operator is simply required to report
the total number of batch cycles in every other periodic
report (i.e., once per year).
Comment: One commenter (IV-D-5) requested that the EPA
clarify that in paragraph 63.486-l(b) the introduction of
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the vent stream into the combustion air for a boiler or a
process heater is equivalent to introducing it into the
flame zone.
Response: The EPA agrees that the introduction of the
vent stream into the combustion air for a boiler or process
heater is equivalent to introducing it into the flame zone.
However, the EPA does not believe that this point needs to
be clarified in the rule.
Comment •. One commenter (IV-D-26) believes that the
rule should provide a 20 ppm concentration alternative to
the 90 percent control device efficiency requirement for
batch process vents in paragraph 63.486-1(a)(2).
Response: The EPA decided not to allow the 20 ppm
concentration alternative for batch front-end process vents,
because the emission standard for batch front-end process
vents is not an instant-in-time limit, but rather a set
emission reduction for a given event (i.e., 90 percent
reduction for the batch cycle).
5.4 TEST METHODS AND MONITORING
Comment: One commenter (IV-D-26) stated that the
proposed batch monitoring requirements are not
cost-effective. The commenter suggests that EPA should
consider more practical monitoring schemes developed in the
States of New Jersey and Kentucky. Based on these systems,
the commenter recommended that reading and recording should
only be required when the source is venting emissions to the
control device. The commenter asserted that once per hour
is an excessive monitoring requirement, and that once per
batch, per transfer for storage tanks and transfer racks,
and per shift for other continuous operations is more
reasonable.
Response: The EPA believes that the proposed rule was
misinterpreted by the commenter, but acknowledges that it
was potentially unclear. Based on the comments made, the
EPA believes that the commenter was under the impression
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that operating parameters for batch front-end process vents
had to be monitored 24-hours per day; this was not the
intent of the rule. In the final rule, the EPA has
clarified that operating parameters for batch front-end
process vents must be continuously monitored (i.e.,
measurements made at least every 15 minutes) during those
batch emission episodes that the owner or operator has
selected to control as part of meeting the requirement to
reduce emissions by 90 percent for the batch cycle.
Several changes or clarifications that affect this area
were made to the final rule. First, in §63.489 [old section
63.486-3] (a)(1) of the final rule, changes were made to
clarify that "monitoring equipment shall be in operation at
all times when batch emission episodes, or portions thereof,
that the owner or operator has selected to control are
vented to the control device...." Second, it was necessary
to clarify §63.486-1(a)(2) to ensure consistency with and
understanding of the change described above. In the
proposed rule, the requirement to achieve 90 percent for the
batch cycle was not expressed clearly. In the final rule,
§63.486-1(a)(2) states that emissions for the batch cycles
must be reduced by 90 percent and that "owners or operators
may achieve compliance with this paragraph through the
control of selected batch emission episodes or the control
of portions of selected batch emission episodes." The EPA
believes that, taken together, the two changes described
above make it clear that parameter monitoring is only
required when emissions selected for control by the owner or
operator are vented to the control device.
A third point to be made does not involve parameter
monitoring for purposes of demonstrating continuous
compliance, but instead involves parameter monitoring during
performance tests. In the final rule, an owner or operator
must either (1) test and monitor the entire batch emission
episode, or portion thereof, selected for control, or
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(2) test and monitor a selected period of the batch emission
episode, or portion thereof, selected for control. A
selected period may be tested when the emission rate for the
entire episode can be determined (i.e., when emissions are
representative of the average emission rate) or when the
emissions are greater than the average emission rate (i.e.,
at the peak of the episode). The pertinent point related to
monitoring is that an owner or operator is required to
gather parameter monitoring data over the entire performance
test.
Comment: One commenter (IV-D-14) disagreed with the
requirement in section 63.486-3(b)(1) to continuously
monitor scrubbing liquid temperature and specific gravity
when using an absorber as a recovery device. The commenter
stated that since other controls and monitors will be
located on the downstream flare, this extra burden is not
justifiable. The commenter also stated that sources'
options for demonstrating compliance should not be
restricted by requiring that a specific gravity monitoring
device be used on an absorber.
Response: The commenter raises two issues. The first
is related to the viability of monitoring the specific
gravity of the absorber liquid. The EPA agrees that in some
situations it may not be necessary to monitor the specific
gravity of the absorber liquid. However, the decision to
forego monitoring the specific gravity of the absorber
liquid in lieu of another parameter is best determined on a
case-by-case basis in concert with the performance test. If
the commenter wishes to monitor another parameter, they
could pursue such an option through the provisions for
obtaining alternative monitoring parameters.
The second issue is related to the combination of
recovery and control devices to control batch vent
emissions. The EPA recognizes that monitoring parameters
for two different devices could be burdensome in some
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instances. One option would be to only require monitoring
of the final control or recovery device. However, the EPA is
not convinced that this would guarantee that the 90 percent
emission reduction requirement is continuously being
achieved. In the situation described by the commenter (an
absorber followed by a flare), it is reasonable to expect
the flare to achieve the required emission reduction.
However, if two recovery devices were used in series, the
EPA believes that both devices could be needed to achieve
the required emission reduction. Therefore, the EPA did not
change this requirement in the final rule. In cases such as
the one described by the commenter, the EPA believes that
alternative monitoring should be requested in the
Precompliance Report or operating permit application
submitted to the permitting agency, if the owner or operator
believes that the promulgated monitoring requirements are
still a burden.
5.5 ASSOCIATED DEFINITIONS
Comment: Two commenters (IV-D-18 and IV-D-14) stated
that the definition of "batch cycle limitation" should be
revised to delete the last 2 sentences, as these provisions
to establish certain types of limitations are substantive
requirements that are not appropriate in the definitions
section of the rule. Furthermore, one commenter (IV-D-18)
contended that the additional sentences are not literally
correct, as the owner or operator of a Group 2 batch front-
end process vent does not always have to establish a batch
cycle limitation; instead, the owner could control the vent
as if it were Group 1.
Response: The definition of batch cycle limitation was
revised to remove regulatory wording that did not belong in
the definition. The definition now reads as follows:
Batch cycle limitation means an enforceable restriction
on the number of batch cycles that can be performed in
a year for an individual batch front-end process vent.
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The wording that was removed from the definition was moved
to section 63.486-1 of the final rule.
5.6 MISCELLANEOUS
Comment: One commenter (IV-D-18) requested that the
EPA clarify that a reevaluation of applicability status for
storage vessels and batch process vents should only be
required if a change is made that might reasonably change
the rule applicability to a vessel or vent. The commenter
stated that conducting this reevaluation for all changes is
burdensome and unnecessary. The commenter added that the
phrase "change in material" should be clarified to mean a
change from one material to another. As currently phrased,
it could mean minor variations in the material, which the
commenter did not believe to be appropriate or intended.
Response: The EPA believes that the proposed standards
address this concern as it relates to Group 2 batch process
vents. The proposed provisions in section 63.486-2(i)
address process changes to Group 2 batch process vents and
the requirement to perform a new group determination. These
provisions provide examples of what things are process
changes and what things are not process changes. Also,
these provisions state that "changes that are within the
range on which the original group determination was based"
are not considered process changes. This allows an owner or
operator to perform the initial group determination with the
minor process changes cited by the commenter in mind. The
EPA believes that the proposed standards were clear that
truly minor process changes (variations in operating
conditions) do not require that a new group determination be
performed. Addressing this concern as it relates to Group 1
batch process vents, the proposed standards do not require a
redetermination of groups status for Group 1 batch process
vents. Therefore, if minor process changes, as cited by the
commenter, were to occur, the owner or operator would not be
required to perform another group determination. The EPA
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does not believe that any changes to the final rule [new
section 63.488] are warranted on the basis of these
comments.
Comment: Two commenters (IV-D-23 and IV-G-2) expressed
concern about differences between the proposed rule and
existing State requirements.
One commenter (IV-D-23) voiced concern about potential
conflicts between Federal and State regulatory requirements,
adding that it is important that consistency between new
source MACT standards and existing new source review
activities be maintained. For example, this commenter noted
that under the proposed rule, Group 2 front-end process
vents do not require controls, but the commenter stated that
it may be appropriate, as well as economically feasible, to
require controls on upstream equipment whenever cumulative
emissions of Group 2 streams may result in significant
combined emissions.
The other commenter (IV-G-2) stated that they currently
regulate the sources covered under this proposal'by RACT
rules, which by definition should be less stringent than
MACT requirements. However, the commenter stated that there
are several areas where the MACT standard is less stringent
than their RACT rules. The commenter attached relevant
sections of their VOC RACT rule to illustrate this point.
Response: In developing the batch front-end process
vent requirements, the EPA relied on EPA's Batch ACT
document, which is EPA's guidance to State and local
agencies in developing RACT for batch processes. Therefore,
the EPA considers the batch vent control requirements to be
approximately equivalent to RACT.
The EPA would remind the commenter that the MACT
"floor" is based on the average emission limitation achieved
by the best performing 12 facilities in a source category
(or 5 facilities for source categories with less than 30
sources). Since all but one of the elastomer source
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categories and subcategories contain less than 5 sources,
the MACT floor was determined as the average emission
limitation for all the sources in the category or
subcategory. Therefore, it is possible that MACT could
actually be less stringent than RACT in some instances.
The Batch ACT discusses a two-phased approach for
determining applicability. The first step is to apply the
applicability criteria to individual vent streams. The
second approach is to combine batch vent streams and
determine if controls are required for the combined streams.
The EPA considered this combined stream approach in the
development of the batch front-end process vent provisions,
but rejected it because elastomer production facilities do
not typically have a large number of batch process vents.
Comment: One commenter (IV-D-18) stated that section
63.486-5(a) implies that other records in addition to those
listed should be kept for batch process vents because of the
words "shall include." The commenter provided suggested
language to eliminate this problem.
Response: To avoid any confusion, paragraph 63.491
[old section 63.486-5] (a) of the final rule has been
revised to state that "Except for paragraph (a)(l) of this
section, the records required to be maintained by this
paragraph are limited to the information developed and used
to make the group determination under section 63.488 [old
section 486-2] (b) through section 63.488(g), as
appropriate."
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6.0 BACK-END PROCESS OPERATIONS
6.1 APPLICABILITY REQUIREMENTS
Comment: One commenter (IV-D-ll) agreed with the EPA's
decision to exempt nitrile latex from downstream controls
after stripping. Another commenter (IV-D-4) stated that
section 63.487-1 should be revised to clarify that
epichlorohydrin and nitrile butadiene rubber are exempt from
back-end controls, because no weekly residual organic HAP
limit has been provided for these products.
Response: The back-end process provisions are
primarily intended to reduce emissions of residual HAP that
occur during the drying of solid elastomer products. In the
introduction to section 63.493, affected sources that only
produce latex products are exempt from the back-end process
provisions Also, in response to comments, affected sources
that produce only liquid rubber products were also
considered exempt from the back-end process provisions. For
both of these types of products, the final elastomer product
is not a solid; therefore, no drying occurs and there is
limited potential for back-end process HAP emissions. For
this reason, affected sources producing only latex products
or only liquid rubber products are exempt from all back-end
process provisions.
As discussed in the Basis and Purpose document for the
proposed standards (section 6.4), the back-end process
operation MACT floors for neoprene, Hypalon™,
nitrile-butadiene rubber, butyl rubber, halobutyl rubber,
epichlorohydrin elastomer, and polysulfide rubber, were
determined to be "no control." Therefore, paragraph 63.494
[old section 63.487-1] (a) (4) indicates that these products
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are not subject to back-end residual organic HAP
limitations. However, each of these elastomers are produced
as solids, the process back-end operations closely resemble
the operations of the elastomer products with residual
organic HAP limitations, and these processes emit HAP from
the process back-end (over 750 Mg/yr baseline HAP
emissions). Due to these factors, the EPA does not believe
that it is appropriate to exempt these products totally from
the back-end process provisions in the introduction to
section 63.493.
Comment: Two commenters (IV-D-8 and IV-D-18) supported
the EPA's proposal in section 63.487 to exempt the back-end
of styrene butadiene latex processes from additional
controls. However, another commenter (IV-D-25) stated that
styrene butadiene latex facilities have filtration processes
after the stripping operation which could have significant
HAP emissions. This commenter requested that the EPA
examine emissions from these operations, and include them as
affected sources in the final rule.
Response: In the development of the proposed
regulation, the EPA analyzed HAP emissions from operations
downstream of the stripper in styrene-butadiene latex
operations and determined that these operations would never
exceed the general applicability requirements of the rule.
This is due to the low concentration of residual HAP in the
stripped latex due to both the high styrene and butadiene
conversion in the polymerization reaction, and the high
stripping efficiency. The EPA does not believe that it is
appropriate to impose reporting and recordkeeping
requirements for these sources, when no associated emission
reduction is anticipated.
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6.2 EMISSION LIMITS
6.2.1 Averaging Period
Comment: Several commenters (IV-D-3, IV-D-10, IV-D-11,
IV-D-16) stated that compliance based on a weekly average
HAP limitation is unreasonable, and that compliance should
be demonstrated on the basis of a monthly (or 30-day)
rolling average instead. These commenters claimed that
requiring compliance based on a weekly average fails to
provide adequate operational flexibility for manufacturers
to produce different grades of polymers in accordance with
customer demands. A weekly averaging period does not allow
sufficient time to correct for "bad batches" according to
the commenters.
Response: Upon review and consideration of the
comments, the EPA agrees that a monthly averaging period for
the residual HAP limitations is more appropriate. Changing
to a monthly averaging period will provide more operational
flexibility to elastomer producers, while maintaining the
same annual emission reduction. As discussed in'the
following section, the EPA has adjusted the back-end
residual organic HAP limitations based on comments received.
As part of this adjustment, the annual data will be adjusted
to monthly instead of weekly.
6.2.2 Residual Organic HAP Limitations
Comment: Numerous commenters (IV-D-3, IV-D-5, IV-D-10,
and IV-D-27) commented on the EPA MACT floor calculation for
back-end process emissions from SBR/PBR solution plants.
These commenters stated that they believed the MACT floor
calculation used to establish the residual HAP limit was
flawed, for a variety of reasons. First, the commenters
believed that the EPA has provided no rationale for lowering
the limit from 0.8 kg HAP/100 kg rubber, and that a level,
"somewhere between the mean, median, and mode" does not
represent central tendency. Further, commenter IV-D-3
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suggested that a mean is the correct approach for
establishing the MACT floor.
In addition, the commenters stated that combining data
received from different companies using different sampling
and analytical methods, without establishing whether the
methods achieve comparable results, is not an appropriate
way to establish residual HAP limits. Furthermore, they say
that the rule proposes to measure compliance using a
different method from the companies. The commenters further
stated that if production figures and dryer stack testing
results were used to establish these limits, this approach
is not supportable, as this would assume no emissions
between the stripper and drying operations, as well as no
residual HAP in the final rubber product. The commenters
also expressed concern that in establishing a weekly limit
based on annual data, the EPA did not adjust for weekly
variation, and did not correct to actual dry weight (some of
the data provided to the EPA was an annual average that
included the weight of oil for oil-extended polymers).
Response: Several issues were raised by commenters
pertaining to the back-end MACT floor calculation for the
SBR/PBR solution facilities. The EPA will address each
issue separately.
(1) The first issue pertained to how the back-end MACT
floor was calculated. The commenters stated that a number
"somewhere between the mean, median and mode" does not
represent a central tendency, and that the mean is the
correct approach for establishing the MACT floor.
Originally, the EPA did not use a traditional measure
of central tendency when calculating the floor in the
proposed rule, because in the EPA's judgment, there were
problems with the selection of either the mode, median, or
mean as the MACT floor. The factors considered in this
decision were the relationship of the floor to the actual
performance by all facilities, the number of facilities that
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would be required to install controls to meet the floor, and
the perceived ability of facilities above the floor to
reduce emissions to the floor level. The EPA reevaluated
this rationale and decided that the factors considered in
selecting a MACT floor "somewhere between the mean, median,
and mode" were not as supportable as the arguments made by
the commenters. The EPA decided that one measure of central
tendency should be used, and decided that the mean was the
most appropriate measure for the residual organic HAP
limitation floor determinations. In some situations, the
use of the mean can result in a floor level of control that
is not represented by any available control technology.
However, this did not apply to this situation, where the
emissions used to determine the floor were a result of
process-specific stripping techniques, and not specific add-
on control technologies. Therefore, the EPA redetermined
the MACT floor back-end residual HAP limitation using the
mean value of the emission factors from the four PBR/SBRS
facilities.
(2) The second issue was that combining data from
different companies using different sampling and analytical
methods was an inappropriate way to establish the residual
HAP limits. More specifically, the commenters indicated
that the use of production figures and dryer stack testing
results to establish back-end limits was not supportable, as
this would assume no emissions between the stripper and
drying operations, as well as no residual HAP in the final
rubber product.
The EPA would like to point out that the back-end
emission limit is actually an emission factor limit, which
was calculated by calculating an emission factor for each
facility, then selecting the mean emission factor as the
MACT floor (see previous discussion of issue number 1). For
each company, the emission factor was calculated by dividing
the total reported back-end emissions by the amount of
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rubber produced in the same year. Compliance with this
limit is measured by testing for the residual HAP
concentration in the intermediate product immediately after
it leaves the stripper.
This analysis, and the subsequent regulatory limits,
made three major assumptions. First, it assumed that each
facility reported total back-end HAP emissions, including
emissions between the stripper and drying operations (i.e.,
fugitive emissions). Second, it assumed that the methods
used by the companies to estimate these emissions were
equivalent. Finally, it assumed that all residual organic
HAP in the polymer leaving the stripper was emitted during
the drying and other finishing operations (i.e., that there
was no residual HAP in the product leaving the facility).
The comments caused the EPA to question these
assumptions. Therefore, the EPA held meetings or
teleconferences with all the SBR/PBR solution producers to
obtain information related to these three assumptions. The
EPA wanted to learn (1) if back-end emissions were reported
for dryer stacks only, or if fugitive emissions were taken
into account when the facilities reported back-end
emissions; (2) if the methods used to estimate these
emissions were consistent with the residual HAP test methods
being validated in the industry (see section 6.3.1) ,- and
(3) if there was significant residual HAP remaining in the
product leaving the facility.
During these meetings and conferences (Docket Number
A-92-44, Item Nos. IV-E-16, IV-E-18, and IV-E-23), all
facilities indicated that they did include fugitive
emissions in their original emission estimates, and that the
original method of estimation correlated favorably with the
test methods being validated. Therefore, the EPA concluded
that adjustments to the emission estimates to remedy
inconsistencies were not necessary. It should be noted that
several minor corrections were made as a result of these
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telephone conferences, primarily related to the addition or
removal of small emission points from the back-end total due
to their location in the process.
With regard to the third assumption, the EPA was
informed by one producer that residual HAP does remain in
the final product. As discussed in a later comment,
adjustments were made to correct for this residual HAP.
(3) The third issue expressed by the commenters was
the concern that the EPA did not adjust for weekly
variations when setting the weekly limit based on annual
data. The EPA agrees with this comment that the adjustment
from annual to weekly data was not conducted adequately, due
to the very limited data available to the EPA prior to
proposal. Since proposal, the EPA changed from a weekly
limit to a monthly limit (see section 6.2.1). In addition,
the EPA obtained daily residual HAP data from two of the
four PBR/SBRS facilities. Using this data, the EPA
calculated the ratio of the monthly average residual HAP
content to the annual average residual HAP content. The EPA
then selected the largest ratio, representing the widest
variation of HAP residual concentrations from annual to
monthly. This maximum ratio was then applied to the annual
MACT floor residual HAP level to obtain the monthly residual
organic HAP limitation in the final rule, 10 kg total
organic HAP/Mg rubber.
(5) Finally, commenters were concerned that the EPA
did not express the production data from all facilities in
terms of the dry weight of the rubber. As discussed in
section 6.5, comments were received on the definition of
"crumb rubber dry weight," and the EPA decided to revise
this definition to allow the weight of extender oils to be
included in the crumb rubber dry weight. During the
meetings and conferences discussed above, the EPA verified
the correct production number, including the weight of
extender oil, to use in the emission factor determination.
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Comment: One commenter (IV-D-02) attempted to predict
how the PBR/SBRS MACT floor was determined, and came to the
conclusion that it would be difficult to reasonably create
the proposed limitation for PBR/SBRS. The commenter was
basing his prediction on an assumed residual HAP level
(i.e., emission factor) for his facility of 19 kg/Mg. All
the emission factors used in the analysis were kept
confidential, since the production numbers used to calculate
them were all claimed confidential. What the commenter did
not realize at the time of his comments was that the
emission factor for his facility was approximately an order
of magnitude lower than the number he had estimated, due to
the inclusion of the effects of add-on controls to reduce
emissions at the commenter's facility. These controls are
described below.
As the crumb/water slurry leaves the stripper, it is
stored in storage tanks. These storage tanks are vented to
a condenser to recover toluene solvent. Also, the crumb
dryer exhaust streams are vented to a boiler at this
facility.
Upon learning of this situation, the commenter objected
(see Docket A-92-44, item number IV-E-16), claiming that two
add-on control situations were improperly considered. The
commenter maintained that since neither of these control
systems were in operation for the base year reported in the
questionnaire responses (1990), it was inappropriate to
include their effectiveness in the analysis.
Response: As outlined below, the EPA disagrees with
the commenter on this issue. Section 112(d)(3)(B) of the
Clean Air Act specifies that for subcategories with less
than 30 sources, emission limitations for existing sources
shall not be less stringent than "the average emission
limitation achieved by the best performing 5 sources (for
which the Administrator has emissions information)..."
Absent in this provision is any mention of a required base
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period for the determination of the controls in place at the
top 5 facilities. The EPA believes that section
112(d)(3)(B) gives the Agency the authority, in determining
the MACT floor, to consider any information regarding
emissions that have been achieved by a source prior to the
development of the standard.
The EPA would agree in principle that it may not be
practical to continuously track the installation of control
devices during the development of section 112(d) standards
and continually update the floor analysis based on this
"new" information. This could lead to a constantly changing
floor level that would make impossible the promulgation of
final rules within the timeframes specified by the Act. In
fact, in late 1994, the EPA became aware of another PBR/SBRS
facility that was considering the installation of an
incinerator to reduce back-end HAP emissions. This
incinerator, which began operation after proposal in late
1995, was not considered in the floor. However, as
discussed below, the EPA believes that it is appropriate to
consider controls that were clearly in place during the
development of the standard.
In the commenter's original information submittal to
the EPA dated August 10, 1992 (see Docket A-92-44, item
number II-D-49), two control options were identified to
reduce emissions from the "back-end" of their PBR/SBRS
production operations. The dryer vent streams were shown in
the process flow diagram and in the emission summary table
to be routed to a boiler. Similarly, emissions from PER
crumb storage vessels located just downstream of the
stripper were reported to be routed to a condenser. Other
than the use of the term "control option," there was no
mention that these controls were not in operation at the
time of this original submittal.
In their October 11, 1993 response to a questionnaire
sent by the EPA to clarify information from the original
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submittal (Docket A-92-44, item number II-D-74), the
commenter's facility stated that "the control options were
not in place at the time of the original submittal."
However, the post-control emissions were also reported in
this response.
The EPA has since learned that the boiler began
operation in December of 1992, and the dryer emissions have
been routed to the boiler since that time. The condenser
control was phased-in for the crumb storage vessels, with
the first being routed to the condenser in late 1992. Thus,
the emission levels from the commenter' s controls were
clearly "achieved" prior to the development of the standard,
and were therefore appropriate for the EPA to consider in
determining the MACT floor.
In addition, the EPA maintains that even if the
commenter's controls were not considered in determining the
MACT floor, it would be appropriate to select a more
stringent level of control. The Clean Air Act authorizes
the EPA to consider control levels more stringent than the
MACT floor. In the evaluation of such controls, the Agency
must take into consideration "the cost of achieving such
emission reduction, and any non-air quality health and
environmental impacts and energy requirements ..."
In the evaluation of the impacts of a more stringent
level of control, the EPA can consider the controls in place
at the four PBR/SBRS facilities. As discussed above, the
commenter's facility has controls in place that result in an
emission factor that would be well below a floor level
calculated without these controls. At the baseline
conditions, one other facility's emission factor was also
well below this level. During a November 9, 1995 telephone
conference, a representative of the company owning the
remaining facilities (see Docket A-92-44, item number
IV-E-23) reported that they have installed an incinerator to
reduce their dryer vent emissions at one facility, reducing
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emissions to a degree that would place the emission factor
below the floor level calculated without the commenter's
controls. These representatives also reported that they
have improved the stripping at their other facility to the
point that they believed they could meet the proposed
5 kg/Mg weekly limit. Therefore, it can reasonably be
expected that the other facility can also meet a limitation
more stringent than the MACT floor even without considering
the commenter's controls.
In conclusion, the EPA believes that it is appropriate
to consider the effects of the commenter's controls in the
MACT floor analysis. Further, the EPA believes that there
will be essentially no incremental impact to the industry
between a level of control calculated without the
commenter's controls to the MACT floor level calculated
considering these controls.
Comment: Several commenters (IV-D-10, IV-D-12,
IV-D-16, and IV-D-17) disagreed with the EPA's approach in
developing the MACT floor and residual HAP limits for EPR,
expressing concerns similar to those raised regarding the
MACT floor for PBR/SBRS. These commenters stated that the
back-end residual organic HAP limitation of 9 kg total
organic HAP per Mg of dry rubber crumb leaving the stripping
operation is too low and does not reflect industry data.
One commenter submitted residual organic HAP data (IV-D-17)
to support his contention that the limit for
ethylene-propylene rubber should be at least 11 kg/Mg dry
rubber crumb if a weekly average limitation is specified.
This commenter also believes that the proposed limitation of
5 kg/Mg for new sources may not be achievable with
demonstrated stripping technology, and he requests that the
variability factors used to convert long-term data to a
short-term limitation be reviewed for new sources.
One commenter (IV-D-10) also stated that the limit
fails to account for wide variations in residual HAP among
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different EPR polymer types and families (such as
oil-extended and non-extended, high and low mooney).
Furthermore, the commenter stated that some annual emission
figures were based on stack testing of finishing building
stacks. These results cannot be equated to those from crumb
sampling at the EPA's designated sampling point, because
there are numerous potential emission sources between the
proposed sampling point and the stack testing locations.
Another commenter (IV-D-16) stated that the approach of
establishing the floor at a level between the mean, median,
and mode does not comply with the Clean Air Act
requirements. This commenter also said that using annual
emissions and limited weekly data to establish weekly limits
is inherently uncertain, and may have resulted in an
inappropriate standard. Finally, commenter IV-D-12 said
that the analysis is in error because of differences in
testing, differences in the point of compliance,
extrapolation of annual limits to weekly limits, and a
failure to consider different types of polymer (such as
oil-extended).
Response •. Commenters on the back-end process emission
limits for EPR raised many of the same issues that were
raised for the PBR/SBRS facilities. The EPA's responses on
several of these issues, as they relate to EPR, are the same
as provided in the previous response. For instance, the EPA
agreed that the MACT floor should be based on the mean of
the individual facility emission factors, that the oil
extender weight should be included in the crumb rubber dry
weight, that the averaging period should be monthly, and
that residual HAP remaining in the final product should be
taken into account. Changes were made to the MACT floor
based on these comments.
In response to the comments that the proposed EPR back-
end emission limit was too low and did not reflect industry
data, and that the limit was derived using inconsistent
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data, the EPA undertook the same measures described in the
previous comment to investigate this issue.
As with the PBR/SBRS producers, the EPA held telephone
conferences with each of the four EPR producers using a
solution process (Docket Number A-92-44, Item Nos. IV-E-20,
IV-E-21, IV-E-24, and IV-E-25). Since the MACT floor was
determined making the same assumptions cited in the previous
response, the primary purpose of these conferences was to
learn (1) if back-end emissions were reported for dryer
stacks only, or if fugitive emissions were taken into
account when the facilities reported back-end emissions;
(2) if the methods used to estimate these emissions were
consistent with the residual HAP test methods being
validated in the industry (see section 6.3.1); and (3) if
there was significant residual HAP remaining in the product
leaving the facility.
As a result of these calls, the EPA learned that three
of the four facilities reported total back-end emissions,
which included an estimate of fugitive emissions. These
three companies also reported that the methods used to
determine their original estimate correlated favorably with
the test methods being validated. Only one facility did not
report fugitive emissions and was relating the original
estimate to the new test methods.
The EPA made adjustments for oil extender weight,
residual HAP in the product, and other minor adjustments,
and redetermined the annual MACT floor. In this
determination, the mean was used as the measure of central
tendency.
In their public comments, one EPR facility provided
detailed information on the daily variability of residual
HAP content (see docket item IV-D-17). While similar
information was requested from the other facilities, none
was provided to the EPA. For each month in the data
provided, the EPA determined the ratio of the monthly
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average residual HAP to the annual average residual HAP.
The largest month to annual ratio was then applied to the
annual MACT floor to obtain the residual HAP limitation for
EPR in the final rule, 8 kg/Mg.
Comment: Three commenters (IV-D-12, IV-D-10, IV-D-27)
stated that the proposed standard does not take into account
residual HAP that may remain in the polymer after finishing.
The commenters believe that a certain amount of HAP will
always remain in the product after finishing, and this
should be reflected in the HAP limit. One commenter
(IV-D-12) suggested that a residual HAP content should be
determined and subtracted from the emission rate calculated
at the point of compliance. This commenter proposed that a
standard residual HAP value be assigned to each polymer,
based on historic analyses.
Response: The original calculation of the floor was
made assuming that no residual HAP leaves with the product.
As a result of these comments, the EPA called the four
PBR/SBRS and the four EPR producers and asked them to
quantify the amount of residual HAP remaining in the
finished product. Only one PBR/SBRS producer reported
residual HAP in their product. This producer uses a
different solvent than the other three producers, noting
that this solvent is more difficult to strip than the
solvent used by the other producers. One EPR facility also
reported residual HAP in their product and quantified the
amount. The EPA agreed with the comment that the floor
should be adjusted for the amount of the residual HAP
remaining in the product, so for the two facilities that
reported residual HAP in their product, the EPA added the
amount of residual HAP in their product back into their
respective emission factors.
Comment: One commenter (IV-D-11) stated that it is
unclear how section 114 submittals have been used to develop
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the standard for SBRE; however, the commenter supported the
350 pptn standard for SBRE.
Response: In 1992 and 1993, the EPA requested
emissions and emissions control information from elastomer
producers under the authority of section 114 of the Clean
Air Act. The EPA analyzed the information submitted in the
responses to these requests, and presented the results of
the preliminary SBRE MACT floor analysis to the industry in
December 1994 (see docket item II-B-16). In this analysis,
the EPA was forced to make numerous assumptions to convert
the emissions and production data to latex concentrations.
At the December 1994 meetings, the SBRE industry requested
that the MACT floor be calculated directly from latex data,
which they offered to provide. In January and February of
1995, latex data were provided to the EPA by all four SBRE
producers. However, one of the facilities provided monthly
data, which could not be used in the weekly floor
determination. Therefore, the proposed MACT floor was based
on this residual HAP data from three SBRE facilities. The
back-end MACT floor for the SBRE industry was determined as
a measure of central tendency of the weekly average residual
styrene concentrations from the latex data provided, and the
original section 114 data were not used to determine the
back-end MACT floor.
Two general comments affected the limit for SBRE.
First, as discussed above, the EPA concluded that it was
more appropriate to use the "mean," rather than another
measure of central tendency. Second, the change in the
averaging time from weekly to monthly allowed the use of the
data from all four SBRE producers. Because much of the data
used in this analysis were claimed confidential, the EPA is
not able to further discuss the details of the MACT floor
calculations.
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6.2.3 Compliance Using Stripping Technology
Comment: Two commenters (IV-D-5 and IV-D-10)
recommended that engineering calculations and production
records be sufficient for calculating the amount of latex or
dry weight rubber leaving the stripper. One cotnmenter was
uncertain whether this is allowed in the proposed rule, and
contends that requiring measurements to determine the amount
of latex or dry weight rubber after stripping would be
impractical or uneconomical. The commenters also pointed
out that current State permits allow these numbers to be
calculated using the amount of product and engineering
knowledge. The sections of the rule where the commenters
believed this is relevant are: section 63.487-2(b)(2)(ii),
section 63.487-2(f), section 63.487-3(b)(4), section
63.487-5(b) (1) (iii) (A) & (B), and section 63 .487-
5(d) (l) (ii) .
Response: The EPA agrees that requiring measurements
of the quantity of the material (weight of latex or dry
crumb rubber) leaving the stripper would be impractical and
uneconomical. The intent of the proposed rule was that
production records and engineering knowledge be used to
determine the amount of material processed in the stripper.
Changes have been made in the rule to clearly state that
production records and engineering knowledge are acceptable
methods of determining the quantity of material processed in
the stripper. However, the EPA does not want to preclude
the use of measurement devices, so measurement is also
listed as an acceptable method.
Comment: Two commenters (IV-D-3, IV-D-10) expressed
support for the proposal to allow the use of predictive
computer modeling for compliance purposes. However, one
commenter (IV-D-3) stated that sources should also be
allowed to use stack test results as part of the predictive
modeling or parameter monitoring processes. This commenter
stated that this is necessary because source operating
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permits do not currently require frequent crumb testing, and
allowing the use of stack test results would provide greater
flexibility to the source. The other cotnmenter pointed out
that many companies now use predictive computer modeling in
conjunction with stripper parameter monitoring rather than
sampling. This commenter suggested that sources should be
allowed to use such alternatives to sampling, which in some
cases may be dangerous or uneconomical. However, three
other commenters (IV-D-1, IV-D-23, IV-D-25) expressed some
reservations about whether these systems can be used to
correctly predict final product concentrations of HAP, and
from this to predict emissions from the source, and
recommended that such systems be carefully evaluated and
proven before they can be used for compliance purposes. One
commenter (IV-D-1) added that the model needs to be directly
connected to the stripper, so that any operating problems
can be detected by the model. One commenter (IV-D-25)
stated that predictive computer modeling is a more accurate
reflection of emissions than normal GEM systems, 'as long as
periodic calibration testing is conducted to ensure the
continued accuracy of the system. This commenter favored
allowing such systems if there is a requirement for periodic
calibration against stack testing or another accurate test
method.
Response.- The EPA believes that computer predictive
modeling may be an attractive alternative to the periodic
sampling and stripper parametric monitoring options in the
proposed rule. In addition, the EPA believes that other
alternative means of compliance, such as the one suggested
by commenter IV-D-3, could be acceptable alternatives.
However, the EPA is convinced that the use of computer
predictive modeling is so site-specific that it is not
possible to include general requirements for its use in
subpart U. Nevertheless, the EPA believes that facilities
should have the opportunity to utilize techniques that are
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equivalent to the two options of compliance provided in the
proposed rule for facilities using stripping technology.
The EPA maintains that the opportunity to use techniques
such as these is already available through the alternative
continuous monitoring and recordkeeping provisions in
section 63.506(g).
Comment: The commenter stated that the final
regulation should explicitly provide that not all back-end
emissions must be directed to a control device as long as
the residual HAP limits are met.
Response: A sentence has been added in the
introduction to section 63.493 that explicitly states that
compliance with the residual organic HAP limitations may be
achieved by using stripping technology, or by using control
or recovery devices.
Comment: The commenter (IV-D-19) stated that for the
initial compliance test, a more logical latex sampling
location for determining the initial HAP concentration for
SBRE is the mixed latex in the storage tank (rather than
directly after the stripper). Because of the fact that
latex is stored in the tanks for a period of 8 to 16 hours
at their facility, the latex coming out of the stripper
during the compliance test is not the same latex being fed
to the coagulation/dryer equipment.
Response: The EPA agrees with the commenter. However,
in addition to the consideration of the sampling point for
initial compliance testing for sources complying with the
back-end process provisions through the use of add-on
control, this comment resulted in EPA's review of the
sampling location in section 63.495 [old section 63.487-2]
(d) for all compliance options. This decision led to the
conclusion that the proposed requirement to sample latex
"after the stripping operations before any opportunity for
the emission of organic HAP to the atmosphere" was not
warranted. The EPA believes that there is little
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opportunity for styrene emissions from the latex after the
stripping operation. In fact, as discussed in section 2 of
this document, the EPA has determined that the emission
potential of all SBL storage and surge control vessels is so
low that they are exempt from the regulation. Further, the
industry has pointed out that often stripped latexes are
blended prior to coagulation, which can affect the residual
styrene content of the coagulated crumb going to the dryer.
Therefore, rather than change the sampling location for
initial compliance testing of add-on control devices, the
EPA revised section 63.495 [old section 63.487-2] (d)(1) as
follows:
For styrene-butadiene rubber produced by the
emulsion process, the sample shall be a sample of
the latex taken at the location specified in
either (d) (1) (i) , (d) (1) (ii) , or (d) (1) (iii) of
this section.
(i) When the latex is not blended with other materials
or latexes, the sample shall be taken at a location meeting
all of the following criteria:
(A) After the stripping operation,
(B) Prior to entering the coagulation operations, and
(C) Before the addition of carbon black or oil
extenders.
(ii) When two or more latexes subject to this subpart
are blended, samples may be taken in accordance with either
(d)(I) (ii)(A) or (B) of this section, at a location meeting
the requirements of (d)(1)(i)(A) through (C) of this
section.
(A) Individual samples may be taken of each latex
prior to blending, or
(B) A sample of the blended latex may be taken.
(iii) When a latex subject to this subpart is blended
with a latex or material not subject to this subpart, a
sample shall be taken of the latex prior to blending at a
location meeting the requirements of (d)(1)(i)(A) through
(C) of this section.
In addition, the EPA has revised section 63.496 [old section
63.487-3] (b)(3) to clarify that the sample of latex
analyzed for residual styrene must be representative of the
latex that is the origin of the crumb being processed in the
dryer, or other back-end unit operation, for which the
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compliance test is being conducted. This section also
specifies a similar requirement for PBR/SBRS and EPR crumb.
Comment: Several commenters (IV-D-1, IV-D-3, IV-D-5,
IV-D-10, IV-D-12, IV-D-18) submitted comments on the
proposed requirement for sampling to take place before any
opportunity for emissions to the atmosphere. Four of the
commenters (IV-D-3, IV-D-10, IV-D-12, IV-D-18) found this
requirement to be either infeasible or unsafe, and suggested
modifications to the provisions, indicating either that
sampling should take place as soon as safe and feasible
after the stripping operation (IV-D-10), at the point where
emissions to the atmosphere occur (IV-D-12), or before
substantial emissions to the atmosphere (IV-D-18). One
commenter (IV-D-3) stated that at least one of its processes
will not be able to meet the requirement for sampling to be
conducted before opportunity for emissions to the
atmosphere, as this process will not permit a closed
sampling system because of safety concerns. This commenter
recommended a revision to the sampling location requirements
that would minimize the opportunity for emissions to the
atmosphere (see language provided on page 3). Another
commenter (IV-D-5) suggested that the provision be revised
to require that the location for measuring latex be set
either immediately after the stripping operation, or at a
location just prior to entering the finishing or back-end
operations, when the plant has no strippers (instead of
immediately after the reactors when the plant has no
strippers). Finally, one State commenter (IV-D-1) stated
that the safety considerations regarding the sampling
location would be the same as elsewhere in the plant, but
that the sampling requirement could necessitate the addition
of a gas chromatograph to distinguish between chemicals in a
fluid flow, and this would be an expensive, albeit
technically feasible, addition.
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Response•. As discussed earlier, the EPA has revised
the sampling location requirements for styrene-butadiene
rubber by emulsion producers. The EPA recognizes the safety
and technical problems associated with the proposed sampling
requirements for polybutadiene and styrene-butadiene rubber
by solution and ethylene-propylene rubber. The EPA does not
believe any of the suggestions made by the commenters are
acceptable as provided. However, the EPA developed a
modified version of one of these suggestions, which has been
added to the final rule. The PBR/SBRS or EPR crumb sample
must be taken "as soon as safe and feasible after the
stripping operation, but no later than the entry point for
the first unit operation following the stripper (e.g., the
dewatering screen)."
Comment: Several commenters (IV-D-10, IV-D-16) stated
that the daily sampling requirement for back-end process
provisions is not appropriate. One commenter (IV-D-16)
requested that in the case of continuous processes, only one
test per "campaign" be required. Another commenter
(IV-D-10) suggested that after a period of daily sampling
where compliance is demonstrated for a particular grade, the
sampling frequency could be reduced to weekly. However, a
third commenter (IV-D-18) supported the EPA's proposed
sampling frequency of one sample per operating day per grade
of elastomer produced. However, the commenter stated that
this could be interpreted to require a sample for a grade
that is begun near the end of the day, or that finishes near
the beginning of the day. Consequently, the commenter
suggested that no sample is needed for brief periods of time
(e.g., 4 hours) at the beginning or end of processing a
particular grade, where processing occurs over a period
greater than one day. Another commenter (IV-D-17) added
that it is impractical to take a rubber sample each
operating day for every grade of elastomer produced, because
of the time required to reach representative operating
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conditions and to run an accurate analytical test. The
commenter suggested a maximum sampling frequency for
practical purposes to be once daily.
Response: Upon review and consideration of these
comments, as well as subsequent discussions with industry
(Docket Number A-92-44, Item Number IV-E-10), the EPA has
decided that one sample per day is sufficient for continuous
processes. Industry pointed out two facts that led the EPA
to this decision. First, the variability of the residual
HAP contents between elastomer grades is relatively small;
and second, production schedules typically produce very
similar grades of polymer for extended periods of time. The
EPA is convinced that reducing the sampling frequency to
once per day for continuous processes would greatly simplify
the rule, while still ensuring that practically all grades
of elastomer produced are represented. The largest contrast
in residual HAP contents is between oil-extended and non
oil-extended grades. However, the EPA determined that
switching between the production of oil-extended'and non
oil-extended polymers on a short-term basis does not occur.
A similar change was made to the sampling requirements
for batch processes. The required sampling frequency was
changed to one sample per batch, rather than one sample per
day per batch.
While the EPA is interested in reducing the sampling
frequency and associated burden, sampling on a less frequent
basis than daily for continuous processes is not an
acceptable option to the EPA. The EPA does not believe that
such an approach would provide adequate verification of the
continued control of back-end emissions.
Comment: Three commenters (IV-D-5, IV-D-10 and
IV-D-12) stated that in some cases multiple samples may be
taken in a 24 hour period (for example, where samples are
used as a process indicator). The commenters suggested that
a provision be added in paragraph 63.487-2(b)(2)(ii) to
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state that if a company samples more than once per day, all
samples taken during the day can be averaged to determine
the residual HAP content.
Response: The proposed rule did not preclude a company
from using more than one sample per day in determining the
weekly average. In order to make this opportunity clearer,
section 63.495 [old section 63.487-2] (b)(2)(i) and
(b) (2) (ii) have been changed to indicate that "at least" one
representative sample is to be taken .... The EPA would
like to point out the proper procedure to utilize multiple
samples taken in a day. The correct procedure is to use the
residual HAP result of the sample, along with the
corresponding weight of material processed in the stripper
in the equation to calculate the monthly weighted average.
The EPA does not intend this provision to permit industry to
average the sample multiple residual HAP results for a day
to obtain a single residual organic HAP average, and then
use this average and the material processed in the entire
day.
Comment: Several commenters (IV-D-10, IV-D-11, IV-D-5,
and IV-D-17) suggested that the rule should provide an
allowance for missed invalid samples to be used in the
calculation of a weekly average, rather than requiring that
every sample be taken and analyzed, and calling the failure
to collect any single sample an excursion. Several
commenters suggested that the EPA should require 75 percent
of the samples to be collected. Another commenter (IV-D-17)
suggested that the rule should allow for the invalidation of
a sample without penalty, for any defensible reason.
Response -. The EPA recognizes that a number of
circumstances could occur that cause a sample not to be
analyzed in accordance with the rule. These may be in the
form of sampling system malfunctions, mis-analysis, or other
problems. The EPA realizes that there are unique challenges
associated with the sampling of solid polymer, and agrees
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that problems could occur that would cause a sample to be
missed. The EPA also recognizes that some of the test
methods being validated to analyze the residual organic HAP
in the crumb take long periods of time to perform, meaning
that the opportunity to obtain a second sample may not be
available if a mis-analysis in the laboratory occurs. While
the EPA expects that sound company procedures could
eliminate most of these and other problems, the EPA agrees
that it is unreasonable to expect that no problems would
ever occur that result in a missed sample. Therefore,
section 63.505(h)(1) has been changed to define an excursion
for back-end process operations as when either (1) the
monthly weighted average is above the applicable limit, or
(2) when less than 75 percent of the required samples are
taken and analyzed in accordance with section 63.495 [old
section 63.487-2] (b). However, the EPA disagrees with the
concept that more than 25 percent of the required samples
could be missed or invalidated without penalty.
6.2.4 Compliance Using Control or Recovery Devices
Comment: One commenter (IV-D-18) suggested that
sections 63.487-3(d) and 63.492(b)(2)(iv) be revised to
clarify that process changes that could impair control
device performance require a redetermination of compliance
status. Another commenter (IV-D-19) added that only changes
that may increase the process's potential to emit should
trigger this requirement. These commenters explained that
the rule as written would require compliance
rede terminations in numerous cases where it does not make
sense to require them, such as when a change makes the
emissions a different color, or reduces the emissions.
Alternatively, the replacement of mechanical or electrical
components could require a compliance redetermination. In
addition, commenter IV-D-18 stated that the proposed rule
also does not specify whether the "organic HAP content"
refers to the HAP that is reacted in and becomes part of the
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polymer, or the residual organic HAP. The cotranenter
suggested that "organic HAP content" should refer to
residual organic HAP.
Response. The commenters are correct in pointing out
that the purpose of compliance redeterminations is to verify
that process changes have not affected the ability of a
control device to meet the requirements of subpart U. While
the EPA believes that some of the interpretations raised by
the commenters are unrealistic, the EPA agrees that the
language in proposal paragraphs section 63.487-3(d) and
section 63.492(b)(2)(iv) [final paragraphs section 63.496(d)
and section 63.505(e)(4), respectively] could be modified to
avoid unnecessary compliance redeterminations. Therefore,
these paragraphs have been changed in accordance with the
suggestions raised by commenter IV-D-18.
Comment -. One commenter (IV-D-18) stated that it is
unreasonable to require sources to assume a 98 percent
control efficiency if a higher control efficiency has been
demonstrated in a performance test.
Response: There are different reasons for which
section 63.496 [old section 63.487-3] (b)(7) exempts certain
control devices from a portion of the source testing
requirements. The first is because the EPA believes it is
impractical to perform performance tests on flares, boilers
or process heaters with design heat input capacities of 44
megawatts or greater, boilers or process heaters where the
vent stream is introduced with the primary fuel or is used
as the primary fuel, and boilers or process heaters burning
hazardous wastes. These devices have traditionally been
exempted from source testing requirements for this reason.
For these devices, section 63.496 [old section 63.487-3]
(b)(8)(ii) indicates that a control device efficiency of 98
percent should be used. However, if a previous performance
test using acceptable procedures indicated that the control
device provided a different level of efficiency than 98
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percent, paragraph 63.496 [old section 63.487-3] (b)(8)(iii)
states that "the control device efficiency shall be the
efficiency determined in the previous performance test."
The example cited by the commenter was a combustion
device that was previously tested for an NSPS and
demonstrated to achieve 99.99 percent. As discussed above,
section 63.496 [old section 63.487-3] (b)(8)(iii) would
allow the use of 99.99 percent in the calculation of outlet
emissions.
Comment: Two commenters (IV-D-10 and IV-D-27) stated
that the rule should consider the effect of condensers
installed on top of crumb storage tanks after the final
stripper. The commenters stated that data submitted to the
EPA indicate that nearly 0.25 percent residual HAP is
removed from the process at this point, and where these
condensers are installed, the residual HAP limit should be
adjusted accordingly.
Response: As noted in the introduction to section
63.493 [old section 63.487], compliance with the'residual
organic HAP limitations may be achieved by using either
stripping technology, or by using control and recovery
devices. The situation described by the commenter is
exactly the circumstance for which the option of complying
by using control or recovery devices was developed. The
requirements of this option are provided in sections 63.496
[old section 63.487-3] and 63.497 [old section 63.487-4] of
the final rule.
Comment: The commenters (IV-D-ll and IV-D-12) stated
that in the future, new products will be harder to strip and
may be better controlled through a combination of stripping
and finishing building controls. Consequently, the
commenter suggested that the EPA allow a combination of
controls to achieve all portions of the standard that apply
to the back-end of the process (process vents, wastewater,
etc.), and asked the EPA to confirm that this option is
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available. Commenter IV-D-12 stated specifically that
customer demands will push EPR production toward lower
molecular weight products that are difficult to strip.
Consequently, the commenter stated that the EPA should
include provisions in the rule for such polymers.
Response: The option of complying with the residual
organic HAP limitations through the use of control and
recovery devices does consider the combined effects of
stripping and the add-on control. The EPA believes that
this option provides the type of flexibility requested by
the commenters. However, the amount of residual HAP
entering the back-end of the process will not be restricted
for facilities using control or recovery devices to comply
with the back-end residual HAP limitations. Therefore, the
EPA believes that wastewater streams at these facilities
should continue to be subject to the provisions of section
63.501 [old section 63.488].
6.3 TEST METHODS AND MONITORING
6.3.1 Residual Organic HAP Tests
Comment: Several commenters (IV-D-10, IV-D-11,
IV-D-16, and IV-D-27) stated that no single analytical
method will produce consistent results for all polymers, and
consequently, each company should be allowed to demonstrate
compliance using a company-specific method that is
comparable to the EPA test method. Alternatively, according
to commenter IV-D-27, a procedure for substituting other
methods should be included in the rule. Two commenters
(IV-D-10 and IV-D-11) specifically submitted their test
methods to the Agency for review, requesting that the EPA
allow these methods to be used as alternative test methods
for the analysis of residual HAP. Another commenter
(IV-D-5) said that additional methods should be provided for
PBR/SBRS, and that they have not yet been able to get
successful results using Method 313. Alternatively, if the
Agency does not incorporate the additional methods used by
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different companies, it should thoroughly evaluate Method
313, as would be done for an ASTM method.
Another commenter (IV-D-17) supported the use of
proposed Method 310 for the determination of residual
organic HAP content in ethylene-propylene rubber crumb
produced by the solution process.
Response: The EPA agrees with the commenters and has
undergone an extensive effort to rectify this situation.
While the finalization of test methods will be addressed in
a separate rulemaking effort, a summary of the action on
this issue is provided below.
In an effort to fully understand the industry's
concerns related to the test methods, representatives of
EPA's Emission Measurement Center participated in a meeting
with industry representatives. Following this meeting, the
EPA concluded that it was appropriate to allow every
interested company to validate their own test method using a
modified version of 40 CFR 63, Appendix A, Method 301.
These validations were conducted not against a reference
method, but rather against a known standard. The EPA
provided the procedures for these validations, and requested
that the companies provide a copy of the validated test
methods in a specified format, along with results of the
validation.
A total of nine test methods were submitted (three for
EPR, three for SERE, and three for PBR/SBRS). Upon review
of the methods and validation data, the EPA approved all
nine methods. Therefore, there will be nine accepted
residual HAP methods that will be referenced in section
63.495 [old section 63.487-2] (e) of the final rule.
Comment: One commenter (IV-D-26) stated it is unclear
in the proposal whether alternative emission monitoring
tests can be used, adding that the final regulation should
state clearly that equivalent test methods are allowed.
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Response: The EPA agrees with the commenter that the
rule should clearly state that alternative test methods are
allowed, provided that such tests are validated by Method
301 of appendix A. The EPA assumes that the comment is
directed to the residual organic HAP test methods in section
63.495 [old section 63.487-2] (e), since paragraph section
63.496 [old section 63.487-3] (b)(5)(iii) clearly states
that, in the evaluation of control or recovery device
efficiency, other Method 301-validated method can be used to
measure the inlet and outlet total organic HAP. A paragraph
has been added to section 63.495 [old section 63.487-2] (e)
to clarify this provision.
6.3.2 Control or Recovery Device Testing
Comment: One commenter (IV-D-15) stated that the
provisions of section 63.487-3(c)(2) may be interpreted to
indicate that each run during the initial compliance test
must be below the residual HAP limitation. The commenter
suggested that it is more appropriate for compliance to be
demonstrated on the basis of the arithmetic mean of three
runs .
Response: The EPA agrees with the commenter, and
section 63.496 [old section 63.487-3] (c)(2) has been
revised to state that the owner or operator is in compliance
if the average of the three test runs is below the residual
HAP limitation.
Comment: One commenter (IV-D-18) supported the
proposal in section 63.487-3(b)(7) to exempt various control
devices from source testing requirements, but disagreed with
other aspects of these provisions. The commenter stated
that it is unreasonably burdensome and unnecessary to
require inlet and outlet emissions to be determined.
Response: The EPA disagrees with the commenter on the
need to measure inlet emissions when previous source tests
have been conducted. Unlike the continuous and batch
front-end process vent provisions, which require a
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percentage emission reduction, the back-end provisions
require that emissions be reduced by the control or recovery
device to a level equivalent to the emissions that would
occur if the facility were complying with the residual
organic HAP limitations in section 63.494 [old section
63.487-1] through the use of stripping technology. In
gathering and analyzing data from this industry, the EPA has
found that fugitive emissions from process back-end
operations are significant, and that many facilities have
previously failed to account for these emissions. The
requirement to determine the inlet emissions, in conjunction
with a determination of the residual organic HAP content of
the material being fed to the back-end process operations,
allows the calculation of these fugitive emissions using a
straightforward material balance. The EPA believes it is
imperative that these fugitive emissions be accounted for in
this manner. The EPA also believes it is unlikely that
previous testing programs have been conducted using an
acceptable method of determining the residual organic HAP
content of the material being fed to the back-end operations
(see Section 6.3.1) and an acceptable method of determining
the inlet emissions to the control device. However, the EPA
does not wish to rule out the possibility that this
situation could occur. Therefore, section 63.496 [old
section 63.487-3] (a) has been changed to allow the use of
previous test results, provided that all conditions of
section 63.496 [old section 63.487-3] (b) were met and
equivalent test procedures were used.
6.4 REPORTING AND RECORDKEEPING
Comment: The commenter requested that the EPA provide
a table like Table 5 under the batch process vent
provisions, to demonstrate the monitoring, recordkeeping,
and reporting requirements for the back-end process
provisions.
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Response: The EPA agrees that such a table would be
helpful to both the regulated industry and agencies charged
with implementing the regulation. Therefore, Table 8 in the
final rule has been added to demonstrate the monitoring,
recordkeeping, and reporting requirements for the back-end
process provisions, as suggested by the commenter.
6.5 ASSOCIATED DEFINITIONS
Comment: Numerous commenters (IV-D-3, IV-D-5, IV-D-10,
IV-D-12, IV-D-16, and IV-D-27) stated that, for solution
processes, the definition of "crumb rubber dry weight"
should not exclude extender oils and carbon black for
compliance purposes, because these are an integral part of
the polymer. The commenters indicated that solution and
emulsion polymerization are extremely different in this
regard and should be separated for the purposes of
determining total weight and calculating residual HAP. In
the solution process, the oil is incorporated into the
polymer prior to stripping, and thus the combination should
be considered one entity. According to the commenters, the
oil has a propensity for holding residuals, and subtracting
the oil weight yields an artificially elevated residual HAP
content per unit crumb, because HAP are found in the oil and
carbon black. The commenters indicated that this definition
will not result in any environmental benefit, but it may
lead to the replacement of oil-extended grades with non-oil-
extended grades, which are more expensive.
Response: Upon review of these comments and further
discussion of this issue with commenters (docket item no.
IV-E-9), the EPA has concluded that the definition of crumb
rubber dry weight should be revised such that the weight of
oil extender and carbon black added prior to coagulation
should not be excluded from the crumb rubber dry weight.
Comment: Several commenters (IV-D-5, IV-D-10, IV-D-18,
and IV-D-8) commented on the proposed definition of
"stripping technology." Three of the commenters stated that
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chemical stripping should be included in the definition,
and the other commenter (IV-D-18) stated that the EPA should
clarify the definition of "stripping technology" to
generally include all types of devolatilization, since it
already refers to the removal of organics by the use of heat
or vacuum.
Response: The EPA has amended the definition of
stripping technology in accordance with commenter
suggestions. The revised definition reads as follows:
Stripping technology means the removal of organic
compounds from a raw elastomer product by the use of
heat and/or vacuum. Stripping technology includes
steam stripping, direct volatilization, chemical
stripping, and other methods of devolatilization.
Comment: One commenter (IV-D-17) stated that the word
"week" should be defined to avoid compliance problems, as
section 63.487-1 establishes back-end residual organic HAP
limitations in terms of weekly weighted averages. The
commenter suggested that a week should be any consecutive
seven operating day period, and those days when a plant is
not producing rubber should not be included in the weekly
average. A suggested definition was included.
Response: As discussed in section 6.2.1, the averaging
period for the back-end residual organic HAP limitations in
the final rule was changed to monthly. Therefore, a
definition of week is not needed. However, the concept of
the commenter's suggestion is still valid, and the EPA has
defined month in the final rule as a calendar month or "a
repeating 30-day period". The monthly weighted average
residual organic HAP content is to be calculated based on
the actual production during the calendar month. The EPA
believes that moving to a monthly average should eliminate
the concern expressed by the commenter over non-production
periods.
Comment: Several commenters (IV-D-3, IV-D-5, IV-D-10,
and IV-D-18) stated that the definition of "grade" should be
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revised to distinguish physical or chemical alterations that
might result in differences in HAP emissions. They
suggested that appropriate characteristics to use in
defining grades include molecular weight, monomer
composition, presence/absence of extender oil and/or carbon
black, while changes in minor constituents such as
antioxidants should not be considered grade changes. The
commenters suggested that the proposed definition of "grade"
could result in small changes that do not affect emissions
being considered grade changes, and triggering burdensome
requirements. Several of the commenters supported the Texas
Natural Resource Conservation Commission's definitions of
normal bound styrene grade (less than 24.5 percent styrene)
and special grade (greater than or equal to 24.5 percent
styrene) for identifying the grades of styrene butadiene
elastomers produced by emulsion processes. For solution
processes, grades could be identified based on the solvent
used. One commenter (IV-D-18) provided a list of examples
and posed the question whether EPA would say there are two
grades of elastomer involved. The commenter requested the
EPA's response to these examples, and stated that in most
cases, a classification as two grades for these examples
would constitute an excessive burden.
Response: The elastomer "grade" was integral to three
elements of the back-end provisions of the proposed rule.
For facilities complying with the provisions of section
63.487-1(a) using stripping technology and periodic
sampling, a sample of crumb rubber or latex was required to
be taken "each operating day for every grade of elastomer
processed" for continuous stripping operations. The
residual HAP content of this sample, determined in
accordance with the specified test methods, would be used in
the weekly weighted average residual organic HAP content.
Upon additional conversations with these commenters
(Docket item number IV-E-10) the EPA has concluded that the
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requirement described above could produce an unintended, and
possibly unreasonable, burden. The EPA believes that the
intent of these proposed requirements, which was to account
for the variability of the residual HAP content of different
polymers, can be achieved by requiring daily sampling. The
industry explained that one sample per day would, for all
practical purposes, mean that all "grades" of polymer
produced would be sampled and included in the weighted
average. In conclusion, the EPA has changed the sampling
requirements in section 63.495 [old section 63.487-2]
(b)(2)(ii) to require that for continuous stripping
operations, at least one sample is to be taken each
operating day. Therefore, this eliminates the use of the
term grade in this context, which alleviates the primary
concern of the commenters.
The second use of the term "grade" is in section 63.495
[old section 63.487-2] (c). An owner or operator complying
with the residual organic HAP limitations through the use of
stripping technology and demonstrating compliance by
monitoring stripper parameters must establish stripper
monitoring parameters for each grade of elastomer produced.
The third use of the term grade was in the carbon
disulfide limitations for SERE producers in section 63.500
[old section 63.487-7]. The owner or operator was required
to develop (and subsequently follow) a standard operating
procedure, for every grade of rubber produced using a
sulfur-containing reaction terminator (shortstop agent), in
order to monitor concentrations of CS2 in the dryer stacks.
A distinction between SBRE polymer grades is needed to
distinguish between polymers with different CS2 emission
potentials. The EPA agrees with the commenters that the
proposed definition of grade was much too broad to serve
these purposes. Therefore, the definition of grade has been
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revised in accordance with commenter suggestions, as
follows -.
Grade means the subdivision of an elastomer
product type by different characteristics such as
molecular weight, monomer composition, significant
mooney values, and the presence or absence of extender
oil and/or carbon black.
6.6 CARBON BISULFIDE LIMITATIONS
Comment: Several commenters (IV-D-5, IV-D-10, IV-D-11)
stated that section 63.487-7 should be revised to specify
that if carbon disulfide precursors are not used in the SBR
emulsion process, the requirements of this section should
not apply, including testing and standard operating
procedure requirements (i.e., the requirement should apply
only to sulfur-containing shortstopping agents, not all
sulfur-containing additives).
Response: The intent of section 63.500 [old section
63.487-7] was to instruct the owner/operator in how to
demonstrate and assure compliance with the carbon disulfide
emissions requirements. The EPA has investigated this issue
and learned that SBRE is produced with sulfur-containing
additives that do not produce carbon disulfide emissions.
Therefore, the EPA agrees with the commenters that this
section in the proposed rule was too general. The EPA has
revised this section in the final rule so that testing and
standard operating procedure requirements apply only when
sulfur-containing shortstop agents are used, and not when
all sulfur-containing additives are used.
Comment: Two commenters (IV-D-10 and IV-D-11)
suggested that when testing is required for the CS2
limitation, the standard should be expressed as a mass
limit, as required in many permits, rather than as a stack
gas concentration. While no commenter suggested a limit on
the quantity of raw material as a possible alternative, one
commenter (IV-D-25) stated that placing limits on the
quantities of raw materials used is an acceptable method of
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limiting carbon disulfide emissions only if testing is used
to verify the level of emissions, because there is not a
linear connection between the quantity of raw material and
resultant emissions. The commenter stated that changes in
the raw materials or significant process changes would
require a retest to confirm continued reduction of carbon
disulfide emissions.
Response: The EPA's primary reason for using a
concentration limitation for carbon disulfide (CS2) instead
of an annual mass emission limit was to avoid a limitation
that could possibly result in a production limitation. It
was reported to the EPA that CS2 emissions are proportional
to the amount of sulfur-containing shortstop used.
Therefore, to limit the annual mass emission rate of CS2
would result in a limitation of the sulfur-containing
shortstop precursor used, which in turn would set a limit on
the production of those products that use the sulfur-
containing shortstop. Additionally, a concentration limit
is easier to calculate and enforce compared to an annual
mass emission rate.
The EPA re-evaluated the 10 ppmv limit by gathering
additional data. The proposed limit was calculated as the
average of the data from only the best performing facility.
Since proposal, the EPA was able to calculate tested CS2
concentrations from a second facility. Then, the EPA
calculated the maximum CS2 concentrations for both
facilities. This was done by scaling up the CS2
concentration using the ratio of their production capacity
over their actual production rate. The average of both
facilities' highest CS2 concentration was then calculated
and assigned as the MACT floor. The revised CS2 limit is 45
ppmv.
Comment; The commenter stated that the rule should be
revised to specify that only changes in the standard
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operating procedures that could increase the concentration
of carbon disulfide in a crumb dryer exhaust above 10 ppmv
should require recertification of compliance, submittal of
test results, and notification.
Response: The EPA agrees that the standard operating
procedure for monitoring carbon disulfide emissions should
be revised to specify that only changes in the standard
operating procedure that increase carbon disulfide emissions
require recertification. As noted above, several commenters
noted that there are sulfur-containing additives other than
reaction terminators (i.e., shortstops) that do not increase
carbon disulfide emissions, thereby rendering the statement
in the proposed rule to be too general. The final rule has
been modified to reflect this change.
Comment: Two commenters (IV-D-5, IV-D-10) suggested
that the sampling point for carbon disulfide performance
testing be changed to a representative location after
emissions exit the dryer prior to leaving the stack. One
commenter stated that it is difficult to sample most dryer
stacks where the dryer exhausts to the atmosphere. In
addition, the commenter says that modifications to Method 18
are necessary to sample for carbon disulfide in a dryer
stack, and he believes these changes should be allowed
without undergoing Method 301 validation.
Response: The EPA contacted the commenter and learned
that the modifications needed at their facility for testing
carbon disulfide emissions are covered within the Method 18
format (REFERENCE DOCKET ITEM NUMBER). Therefore,
modifications to Method 18 will not be needed and the
comment is no longer valid.
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7.0 WASTEWATER OPERATIONS
7.1 BASIS FOR THE STANDARDS
Comment: Two commenters (IV-D-17 and IV-D-10) pointed
out that the wastewater provisions of subpart G that are
referenced in section 63.488 of subpart U are the subject of
litigation brought by the Chemical Manufacturers'
Association against the EPA. Consequently, sources subject
to these provisions cannot know what the final wastewater
provisions, proposed to be incorporated into subpart U,
will be. The commenters suggested that the EPA "reserve"
the provisions of section 63.488 pending the outcome of the
litigation. The commenter added that the EPA should
indicate that when these provisions are finalized, they will
be considered for incorporation into subpart U, a further
comment period will be provided, and a compliance schedule
will be provided allowing 3 years from the date section
63.488 is finalized for compliance. One commenter (IV-D-10)
also stated that the definitions of "wastewater" and "point
of generation" were challenged in the HON litigation, and
these definitions must be amended in the final subpart U
rule to conform to the outcome of the litigation.
Response-. As part of the HON litigation proposal, the
EPA will request comments specific to the elastomers rule.
If comments specific to the elastomers rule are received
they will be addressed as part of the HON rulemaking actions
or in actions specific to the elastomers rule, depending on
the comments. Therefore, the comment period for this rule
will not specifically be reopened.
The EPA believes that the wastewater provisions and the
other HON provisions should be referenced in the elastomers
rule so that final resolutions of the HON litigation will be
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automatically included in the elastomers rule. However,
changes made to the HON will be evaluated by the EPA for
applicability to this rule. The "automatic" part refers to
the fact that text changes will not need to be made to this
rule once the EPA, following notice and opportunity for
comment, finds the HON changes to be applicable. If the EPA
determines that any changes to the HON are not applicable to
this rule, the elastomers rule will be revised to reflect
that.
Comment: One commenter (IV-D-14) stated that the EPA
has not recognized the differences between elastomers and
SOCMI operations in establishing wastewater provisions for
the proposed rule. The commenter stated that the EPA has
not fulfilled its statutory requirement to consider controls
appropriate to the source category. The commenter added
that the references to the HON wastewater provisions
increases the complexity of the proposed rule.
Response: The EPA rejects the suggestion by the
commenter that the EPA simply incorporated the HON
provisions without considering the appropriateness for the
elastomer industry. In determining whether the controls
were appropriate, the EPA compared the levels of control in
place at elastomer production facilities with the HON levels
of control. Based on this comparison, the EPA concluded
that the HON wastewater applicability and control provisions
were appropriate for the elastomer industry.
7.2 APPLICABILITY REQUIREMENTS
Comment: One commenter (IV-D-10) noted that the VOHAP
threshold for regulation of new source wastewater streams
(10 ppmw) is too restrictive, and that the EPA has not
provided an economic justification regarding the
achievability of the limit.
Response: In response to this comment, the EPA
evaluated the new source MACT floor determinations for
wastewater. In this analysis, the existing wastewater
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controls were compared to the control level that would be
required by the HON wastewater controls, and each facility
was designated as being controlled at a level less than,
equal to, or greater than the HON. For all subcategories
except one (Butyl Rubber, which was less than the HON), the
MACT floor for wastewater was determined to be equal to the
HON, meaning that the majority of the facilities in the
category or subcategory were controlled at the HON level of
wastewater control. In many instances, facilities were
reported to be controlled at the HON level because they had
all uncontrolled wastewater streams that would not require
control under the HON.
No facility in any category or subcategory was
designated as a facility with controls greater than the HON.
Therefore, for each subcategory, the new source MACT floor
level was set at the HON new source level.
Upon review, the EPA noted that no facility in any
subcategory reported wastewater controls equivalent to the
new source levels. In fact, no facility-wide wastewater
controls greater than the existing source HON limitations
were reported. Therefore, the EPA believes that this
comment is valid, and has changed the final rule so that the
new sources are subject to the same wastewater requirements
as existing sources.
Comment: One commenter (IV-D-10) stated that many
elastomer product process wastewater streams will have VOHAP
concentrations less than 50 ppmw, and monitoring and
recordkeeping requirements are not needed for these streams.
The commenter recommended that the EPA exempt from
regulation "any process stream at an affected source with an
average flow rate of less than 0.02 liters per minute or an
average VOHAP concentration of less than 50 ppmw."
Response: In the proposed rule, the definition of
wastewater stated that a stream must contain at least 5 ppmw
of VOHAP and have a flow rate of 0.02 liter per minute.
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Given the change in the definition of a Group 1 wastewater
stream for new sources, the EPA believes that it is
reasonable to revise the definition of wastewater in
accordance with ths commenter's suggestion. Therefore, the
definition in the final rule has been revised accordingly.
Comment: Two commenters (IV-D-5 and IV-D-10) suggested
that paragraph 63.488(c)(l) be revised to indicate that
back-end wastewater streams "where the stream only comes
from equipment that only produce latex products" are exempt
from control requirements. The proposed rule currently
exempts "Back-end wastewater streams at affected sources
that produce only latex products."
Response•. The EPA believes that the exemption listed
in section 63.501(c) (1) should apply to equipment dedicated
to the production of latex that is located at an affected
source that also produces a solid rubber product.
Therefore, the final rule was changed in accordance with the
suggestion of the commenters.
Comment: Three commenters (IV-D-5, IV-D-4,'IV-D-10,
and IV-D-17) suggested that, in section 63.488 (c) the EPA
clarify that sources exempt from back-end residual HAP
compliance requirements under section 63.487-1(a) (4) [i.e,
Hypalon, NBR, epichlorohydrin, butyl rubber and halobutyl
rubber] are also exempted from back-end wastewater controls.
The commenters assumed that since wastewater streams from
affected units subject to residual HAP limits are exempt,
affected units without back-end residual HAP limits should
also be exempt.
Response: The back-end residual organic HAP
limitations that apply to producers of ethylene-propylene
rubber, polybutadiene rubber by solution, styrene-butadiene
rubber by solution, and styrene-butadiene rubber by emulsion
restrict the amount of HAP that enter the back-end of the
process. If the facility producing one of these elastomer
products is meeting the requirements of section 63.494 [old
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section 63.487-1] (a) by stripping sufficient residual
organic HAP from the polymer before it enters the back-end
process operations, the EPA believes that it is not
appropriate to require control of back-end wastewater
streams. The rationale behind this is that if sufficient
HAP were in back-end wastewater streams to require control,
the residual organic HAP limitations in section 63.494 [old
section 63.487-1] (a) should be lowered. Since facilities
producing elastomer products listed in section 63.494 [old
section 63.487-1] (a)(4) - neoprene, Hypalon, nitrile-
butadiene rubber, butyl rubber, halobutyl rubber,
epichlorohydrin elastomer, and polysulfide rubber - are not
required to limit the amount of residual organic HAP
entering the back-end of the process, the EPA does not
believe that it is appropriate to exempt them from the back-
end wastewater requirements.
7.3 SELECTION OF EMISSION LIMITS
Comment: One commenter (IV-D-11) stated that the
wastewater stripping provisions in subparts F and G, which
are incorporated into subpart U, are not appropriate for the
elastomer manufacturing industry. He added that the
stripper dimensions referred to in the HON will not achieve
the efficiencies necessary to meet the standards, because
the rubber manufactured can coat trays and plug columns.
The commenter requested that the EPA state that equipment
for the elastomer industry should not be the same as for the
HON. Alternatively, existing stripping systems should be
considered adequate if they meet the wastewater and residual
HAP limits.
Response: The HON wastewater provisions referenced in
section 63.501 include four options for treating Group 1
wastewater streams. These are (1) recycle the stream back
to the process, (2) reduce the VOHAP concentration of each
individual organic HAP to less than 10 ppmw, (3) treat the
stream in a steam stripper meeting the specifications
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contained in the rule, or (4) reduce total VOHAP mass flow
rate by 99 percent. If an owner or operator believes that
the design stream stripper is not appropriate for their
process, three other options are provided. Therefore, the
EPA does not believe a rule change is necessary in response
to this comment.
Comment: One commenter (IV-D-15) voiced concern that
the target removal efficiencies for Group 1 wastewater
streams may not be achievable for wastewater generated from
latex production by emulsion, because soap in the wastewater
hinders the strippability of the VOHAP.
Response •. This commenter provided no data to allow the
EPA to evaluate the validity of this concern. Therefore, no
action was taken on this issue.
Comment: One commenter (IV-D-15) wondered whether
biological treatment with a suppressed sewer system may be
used as an alternative control method to steam stripping.
The commenter stated that biological treatment is highly
effective for biodegradable HAP.
Response: The EPA recognizes that biological treatment
is a viable method of reducing the organic HAP concentration
in wastewater. In fact, the EPA considers one of these
compliance options, the use of biological treatment with
enclosed sewers to the biological treatment operation unit,
a favorable option for this situation because styrene is
readily biodegraded. Section 63.138(e) of subpart G allows
the use of a biological treatment unit as a wastewater
treatment alternative.
Comment: One commenter (IV-D-15) stated that covering
drains and impoundments as required for the suppression of
emissions from process wastewater may cause fire or
explosions because of VOHAP build-up in the head space. The
commenter asked whether other methods, such as maintaining a
water seal, may be used to suppress these emissions.
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Response: The EPA recognizes that some of the
wastewater requirements create confined air spaces over
wastewater containing organic HAP, which can cause the
accumulation of organic compounds that are volatilizing from
the wastewater in the headspace. However, the EPA also
believes that the institution of common safety practices can
avoid fires, explosions, exposure of personnel to
oxygen-deficient air, and other safety issues.
Comment: One commenter (IV-D-18) stated that the EPA
should remove the definition of "Group 1 and Group 2
wastewater streams" that says these are identified in
subpart G, and include this term on the list of terms whose
definition has been incorporated from subpart G. As
proposed, these terms are not definitions.
Response: As discussed above, the definition of Group
1 and Group 2 wastewater streams for new sources has been
changed, meaning that the HON definitions are no longer
applicable. Therefore, Group 1 and Group 2 wastewater
streams are defined in subpart U.
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8.0 EQUIPMENT LEAKS
As discussed in Section 3.0, there was confusion among
the convmenters regarding the difference between storage
vessels and surge control vessels. Therefore, some comments
regarding surge control vessels are addressed in
Section 3.0.
8.1 APPLICABILITY REQUIREMENTS
Comment.- One commenter (IV-D-18) stated that EPA
should revise its cross-reference to incorporate the HON
definition of "in organic hazardous air pollutant service."
As written, the rule incorporates the definition of the term
"in organic hazardous air pollutant."
Response: The EPA intended for the HON term "in
organic hazardous air pollutant or in organic HAP service"
to apply to the proposed rule, and this term has been
incorporated into the final rule.
Comment: One commenter (IV-D-27) stated that the
proposed rule should include an exclusion for reciprocating
pumps that must leak small quantities of product to
lubricate and cool the shaft and seal areas. These pumps
will fail the leak definition of 500 ppm, and although some
of these pumps have been replaced, there remains a technical
problem with replacing the pump in two plant locations. The
commenter stated that it is not clear whether the quality
improvement program in 63.176 will offer any relief. The
commenter added that the provisions of section 63.509 should
be incorporated into this rule.
Response: The EPA agrees that an exemption for the
situation described by the commenter is reasonable. The EPA
included a similar exemption in the proposed Polymers and
Resins IV regulation (subpart V). Therefore, section
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63.502(d) has been added that exempts these reciprocating
pump systems.
8.2 COMPLIANCE DATES
Comment: Several commenters (IV-D-5, IV-D-8, IV-D-18)
requested that section 63.481(c) of the rule be revised to
provide three years for compliance with equipment leak
provisions for compressors (instead of six months) under
certain circumstances. One commenter (IV-D-18) said this is
needed when the compressor must be replaced, or the distance
piece must be recast. The other commenters stated that
changes likely to require State construction permits and
therefore requiring three years for compliance are-. (1)
existing reciprocating compressors which would require
design modifications to connect to a closed-vent or recovery
system; and (2) systems where existing compressors would be
replaced.
Response: The EPA agrees with the commenters, and has
amended the compliance schedule for compressors in
accordance with these comments.
Comment: One commenter (IV-D-15) questioned what the
definition of "affected equipment" for equipment leaks. He
asked whether the criteria in the HON (all equipment which
contain or contact a fluid which is at least 5 percent
VOHAP) also apply to the Polymers and Resins I NESHAP.
Another commenter (IV-D-18) indicated that in the cross-
reference to incorporate the HON definition of "in organic
hazardous air pollutant service," the proposed rule appears
to inadvertently leave off the word "service."
Response: Section 63.502 of subpart U directly
incorporates the requirements of subpart H (HON equipment
leak requirements), and section 63.482 directly incorporates
the subpart H definition of "in organic hazardous air
pollutant service" which means "that a piece of equipment
either contains or contacts a fluid (liquid or gas) that is
at least 5 percent by weight of total organic HAP's as
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determined . . . ." The commenter was correct in pointing
out that the reference to this definition was incorrect,
which could possibly be the source of the confusion
expressed by other commenter. This error has been corrected
in the final rule.
8.3 ASSOCIATED DEFINITIONS
Comment: One commenter (IV-D-18) supported the
provisions allowing three years' compliance time for
existing surge control vessels subject to 63.170 of subpart
H. However, the commenter indicated that the definitions of
Group 1 and Group 2 storage vessels are not consistent with
the HON, as the HON includes surge control vessels in a list
of equipment that are not storage vessels. The commenter
recommended that the subpart U rule use the HON's list of
items that are not storage vessels and incorporate this list
into the definitions of Group 1 and Group 2 storage vessels.
Response: The EPA did not intend a surge control
vessel to be considered a storage vessel. Therefore, the
term "surge control vessel" has been added to the list
within the definition of "storage vessel" of tanks and
vessels that are not considered storage vessels.
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9.0 EMISSIONS AVERAGING
Comment: Two cotnmenters (IV-D-18 and IV-D-19)
supported the concept of omissions averaging included in the
proposed rule. They added that it is of critical importance
to facilities for determining the most cost-effective and
reliable way of achieving required emissions reductions.
However, one of the cotnmenters (IV-D-18) stated that the
provisions are so long and complicated that they are not
certain anyone will actually use them.
Response: The EPA allows existing affected sources to
use emissions averaging if they can achieve at least a
comparable hazard and risk benefit to point-by-point
compliance. As the EPA stated at proposal, although there
is limited potential for emissions averaging in this rule,
the EPA did not want to exclude emissions averaging from the
rule. This decision is in keeping with the EPA's general
policy of encouraging the use of flexible compliance
approaches where they can be properly monitored and
enforced. The EPA's goal in providing emissions averaging
provisions in this and other rules has been to make
emissions averaging available to sources faced with some
emissions points that are particularly difficult or costly
to control.
Comment: One commenter (IV-D-14) stated that it would
be appropriate to include batch front-end process vents in
emissions averaging. The commenter added that this would be
advantageous to owners and operators, without having a
detrimental effect on the environment. The commenter
reported having an on-going opportunity to employ averaging
across batch reactor vents at their facilities, and they are
planning to submit additional information to the EPA on this
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topic. The commenter also suggested that equations 35 and
61 in sections 63.490(g)(l) and (h)(l) should be changed to
include actual and allowable terms for batch process vents.
Response: The final rule allows emissions averaging of
existing batch front-end process vents. The equations in
sections 63.503(g)(1) and 63.503(h)(l) have been revised to
include both batch front-end process vents and aggregate
batch vent streams.
Comment: One commenter (IV-D-14) disagreed with the
fact that process units that have been shut down cannot be
used to generate credits or debits, adding that this has no
technical or regulatory validity.
Response: It is not appropriate to allow emissions
averaging credits for process units that have been shutdown.
Regardless of the motivation for a shutdown, the emission
reduction from the production curtailment is not made
permanent if emissions averaging credit is allowed. If
credit were granted for the emission reduction, the source
could then emit an equal amount of emissions from its debit
generators. This is in contrast to point-by-point
compliance, where if a point is shut down, the emissions
reduction is permanent. To allow credit in emissions
averaging for permanent shutdowns results in less stringent
compliance and more total emissions than point-by-point
compliance, in which case emissions averaging does not
represent an equivalent compliance alternative.
Furthermore, allowing emissions averaging credits for
the addition of new process units which are replacing older
process units that have been shutdown is not appropriate.
Although the EPA encourages affected sources to replace
older process units to account for improved technologies,
where cost-effective, emissions averaging credits will not
be allowed in these circumstances because new sources are
not allowed to emissions average under the provisions of the
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rule. The rationale for not allowing emissions averaging
for new sources is included in Volume 2C of the HON BID
(EPA-453/R-94-003c; March 1994).
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10.0 PERFORMANCE TESTING
Numerous comments were received regarding the proposed
residual organic HAP test methods. These comments are
addressed in section 6.0. Following are comments regarding
the general performance test requirements in the rule.
Comment: One commenter (IV-D-18) stated that the rule
should be revised to allow the use of alternative test
methods and procedures approved by the Administrator, The
commenter stated that requiring an alternative test method
to be validated using Method 301 is overly burdensome,
because it assumes that all possible things would go wrong
at the same time. The commenter suggested that all
references to Method 301 should be deleted from the rule.
The commenter cited 10 instances in the rule where revisions
are needed to allow the use of alternative test methods.
Response: The EPA disagrees with the commenter
regarding the usefulness of Method 301. The EPA believes
that adequate flexibility has been added to the final rule
with the addition of provisions allowing the use of Method
25A and allowing demonstrations of compliance based on TOC.
The EPA cannot justify foregoing the use of Method 301 to
validate alternative test methods when no specific comments
concerning its use were provided. If commenters wish to
pursue changes to the procedures for obtaining permission to
use alternative test methods, they should address concerns
to the General Provisions. [Note: Use of different EPA
approved test methods is discussed in the next response.]
In response to the commenter's concern that some
provisions of the proposed rule specified a specific test
method and did not provide flexibility to pursue an
alternative test method, the final rule has been changed to
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specifically cite that other methods validated according to
Method 301 are allowed. However, even when not specifically
stated, owners or operators are always allowed to apply for
use of an alternative test method under the General
Provisions.
Comment: One commenter (IV-D-18) stated that the batch
vent provisions in 63.486-4(b)(3) for exempting a source
from performance test requirements are essentially useless,
because requirements for testing are constantly changing in
small ways, and it is unlikely that any test would ever have
been performed with "the same" procedures as required under
subpart U. Instead, the commenter suggested that if a
performance test has been conducted to demonstrate
compliance with any EPA-administered or EPA-supervised
program, the EPA should allow that test to demonstrate
compliance with subpart U.
Response: In response to this comment, the EPA
considered the open-endedness of the commenter's request and
considered it unreasonable to allow a test done using any
EPA method to suffice for the performance test required by
this rule. However, the EPA found it reasonable to allow
tests done for compliance with an NSPS or NESHAP, where
either total organic HAP or TOC or VOC were measured, to
serve as a substitute for the performance test required
under this rule.
Comment: One commenter (IV-D-18) stated that a
performance test should not be required where process vents
are sent to an RCRA incinerator that complies with 40 CFR
part 264.
Response -. The EPA agrees with the commenter that a
performance test done for an RCRA should be acceptable for
compliance with testing requirements under this rule,- the
final rule allows this. The proposed rule already exempted
boilers or process heaters burning hazardous waste that are
in compliance with 40 CFR part 266. In the final rule,
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combustion devices that are in compliance with either 40 CFR
part 264 or 40 CFR part 266 are exempt from performance
testing requirements.
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11.0 MONITORING
This section addresses comments on the general
monitoring requirements in the proposed rule. Comments
regarding the monitoring requirements of specific segments
(i.e., batch process vents, back-end process operations) of
the rule are addressed in the sections dedicated to those
sections.
Comment: One commenter (IV-D-19) stated that the
requirement in section 63.487-4(d)(1) for an exhaust gas
flowmeter in bypass lines between the process and control
device can be met with devices other than a gas flowmeter.
Specifically, the commenter described a thermal oxidizer
system at their plant which incorporates a bypass vent
upstream of the oxidizer as a safety device. The commenter
asserted that a sensor which would monitor and record the
position of the bypass damper would serve the purpose of
indicating whether a bypass was occurring equally well, and
he interpreted the rule to include their system.
Response: The EPA agrees that the situation described
by the commenter is an acceptable alternative to the options
listed in section 63.497 [old section 63.487-4] (d)(1) and
(2) to ensure that a control or recovery device is not
by-passed. Therefore, this section of the rule was modified
to allow the monitoring of damper or valve position as an
alternative to a flow indicator, a car-seal, or a
lock-and-key configuration.
This same requirement is also contained in section
63.489 told section 63.486-3] (d). In this instance, the
rule has been changed in the manner discussed above.
Comment: One commenter (IV-D-14) did not support the
approach for determining monitoring levels that is provided
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in paragraphs 63.492 (b) (1) (iii) (A) (3. & 4) , because the
commenter asserted that it is not feasible for the
parameters of each batch emission episode in each batch
cycle for each elastomer product for each reactor to be
continuously monitored. The commenter also disagreed with
basing the level on the minimum or maximum of the average
parameter values, because these values may vary widely, and
erroneously indicate excursions. The commenter requested to
work with the EPA to establish a more representative method
for establishing monitor parameters.
Two commenters (IV-D-26, IV-D-14) disagreed with the
use of "level" in the proposed rule. One commenter
(IV-D-26) stated that "range," which was used in the HON,
has been changed to "level" throughout the rule without
adequate justification, and it is arbitrary. The commenters
stated that "level" should be changed to "range" to provide
greater flexibility and be consistent with the HON. One
commenter (IV-D-14) further stated that paragraph (a)(3)
suggests that a source may also have to comply with range
requirements in the HON, and that the intent of this
paragraph is unclear. This commenter suggested that this
paragraph be deleted.
Two commenters (IV-D-14 and IV-D-18) expressed concern
with the method for establishing minimum or maximum
parameter monitoring levels in sections
63.492(b) (l) (iii) (A) (1) and (4) . The commenters disagreed
with the approach (as understood) whereby a minimum
parameter level in a performance test becomes a maximum
monitoring level, and a maximum parameter level in a
performance test becomes a minimum monitoring level. The
commenters contends that essentially, sources are required
to use the worst-case number as the required operating
level, which is not an accurate indicator of excursions, and
that in order to achieve that level, production limits and
stringent raw material specifications would have to be
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implemented, leading to increased costs. Finally, one
commenter (IV-D-18) stated that the worst aspect of these
provisions is that they would have to be implemented for
each piece of equipment, for each emission episode. This
commenter stated that this requirement alone is enough to
guarantee litigation if it is not changed in the final rule.
Commenter IV-D-18 recommended that a "buffer zone"
approach similar to that used in other NESHAP or NSPS be
used instead, and that EPA revise the rule to allow a
monitoring level anywhere within the range that has been
demonstrated to achieve compliance. Alternatively, he
states that at least the average of the minimum datapoints
could be used to establish a minimum monitoring level, and
likewise for a maximum limit. In the worst case, the
commenter stated, the EPA should use the same approach as
for continuous process vents, whereby the monitoring limit
is set at the average of the test run levels.
Another commenter (IV-D-8) disagreed with the proposed
rule's departure from the HON requirements by failing to
allow the use of engineering assessments and manufacturers'
recommendations in establishing the enforceable monitoring
level. The commenter stated that it is not appropriate to
rely upon HON requirements, while selectively imposing more
stringent requirements than the HON.
Response: The approach for establishing parameter
monitoring criteria in the final rule incorporates the
concepts included in the HON rule, thus satisfying all of
the commenter's concerns. This approach requires a
performance test and then allows the owner or operator to
use the results of the performance test in concert with
engineering judgement to determine an operating parameter
level that reflects proper operation of the control or
recovery device. The final rule also retains the parameter
monitoring methods included in the proposed rule which
require a performance test and then specify that the level
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is to be based on the maximum or minimum recorded values as
appropriate. For example, when determining the maximum
operating temperature for a condenser used to control a
continuous process vent, the owner or operator would conduct
three 1-hour test runs. For each test run, four 15-minute
average values of the temperature would be recorded. The
level would be the average of the maximum recorded
temperature (15-minute average value) for each of the three
test runs.
By allowing the affected source to choose between
approaches, the final rule ensures that site-specific
variation in emission point characteristics and control
device designs are considered in establishing appropriate
parameter monitoring levels.
Comment: One commenter (IV-D-18) stated that the
highest (or lowest) datapoint used to calculate an average
that then becomes a parameter limit (maximum or minimum),
should be the point that determines whether or not a
violation has occurred. The commenter asserted that unless
parameters go beyond these levels, rather than the average
level, no violation of the standard has occurred.
Response: The EPA believes the procedures contained in
the proposed and final rule for determining when a parameter
monitoring violation has occurred are valid. The EPA
believes the basis used to develop the parameter monitoring
level and the basis used to calculate average values for the
monitored parameter are equitable in that the averaging
times are equivalent. The data used to develop the
parameter monitoring level is typically based on average
values from a performance test (some parameter monitoring
levels are not based on performance tests). The typical
performance test entails three 1-hour test runs, and the
average that determines the parameter monitoring level is
calculated using a single 15-minute value from each test
run. Likewise, average values for monitored parameters are
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based on 15-minute values; the 24-hour average value is
calculated using all valid 15-minute values, and this
average is compared to the parameter monitoring level.
Further, as stated in the proposal Basis & Purpose Document,
the EPA has concluded that operating parameter monitoring is
an acceptable way to determine whether control devices are
being maintained and operated properly. The commenter is
referred to Section 8.6 for the rationale on this point that
was presented at proposal.
Comment: One commenter (IV-D-18) supported the
provision under 63.492(d)(2) stating that where multiple
parameters are monitored for the same control or recovery
device, an excursion involving one or more parameters is
considered a single excursion for the device. However,
another commenter (IV-D-14) believed that the requirement in
paragraphs 63.492(d)(1) and (2), stating that missing one of
multiple parameters in data collection is an excursion, is
unreasonable. Commenter IV-D-18 also supported the approach
whereby an excursion is determined by the batch cycle daily
average, rather than by hourly or fifteen-minute data
points. Finally, the commenter supported the fact that
under section 63.492(d)(2), "insufficient data" does not
mean a single missing data point.
Response: These provisions are retained in the final
rule. The EPA disagrees with the commenter's suggestion
that the EPA should allow an excursion for one parameters
for those devices with multiple parameters. The EPA asserts
that all parameters that are monitored for an air pollution
control device need to be in compliance to assure that the
device is operating correctly.
Comment: One commenter (IV-D-18) expressed support for
the provision that excursions during a startup, shutdown, or
malfunction are not considered excursions, as long as the
process startup, shutdown, malfunction plan is being
followed. In general, the commenter supported the excursion
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provisions established in the HON, and supports the
inclusion of some of these concepts in the Polymers and
Resins I rule, such as the use of daily average parameter
values to determine excursions.
Response: This provision is retained in the final
rule.
Comment: Several commenters (IV-D-8, IV-D-14, IV-D-18,
and IV-D-26) stated that the EPA should provide a number of
allowed excursions in the rule for every annual permit
reporting period. The commenters asserted that requiring
perfect compliance is neither cost-effective nor
environmentally beneficial.
Response: In the final rule, the EPA decided to excuse
a certain number of excursions for each reporting period.
This decision was based on data and information presented
during public comment on the HON and reiterated in public
comments received on this rule and during industry meetings
held subsequent to proposal that indicated that a certain
number of excursions could be expected even with properly
operated pollution control devices. The EPA also concluded
that not allowing excused excursions would impose
significant additional capital and operating costs on the
affected source for only negligible corresponding reductions
in air emissions. As is always the case, a State has the
discretion to impose more stringent requirements than the
requirements of NESHAP and other federal requirements and
could choose not to allow the excused excursion provisions
of this rule.
The EPA considered the number of excused excursions
that would be most appropriate for this standard and
determined that the number of excursions allowed in the HON
would be reasonable. Therefore, the final provisions allow
a maximum of six excused excursions for the first semiannual
reporting period, decreasing by one excursion each
semiannual reporting period. Starting with the sixth
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semiannual reporting period (i.e., the end of the third year
of compliance) and thereafter, affected sources are allowed
one excused excursion per semiannual reporting period.
Each excursion that occurs during an operating day must
be designated as an excused excursion in order for the
affected source to be considered in compliance. In other
words, if multiple control devices or multiple emission
points experience an excursion, the owner or operator must
designate each excursion as "excused" using the allowable
excused excursions remaining for the semiannual reporting
period in order to be in compliance. As specified in the
final rule, when multiple parameters related to a single
emission point or single control device are outside of their
parameter monitoring levels on the same day, only one
excursion has occurred. Furthermore, problems with one
control device can only result in one excursion per day.
For example, if multiple emission points are ducted to the
same control device, and the parameter monitoring levels for
the control device are exceeded, this would be a'single
excursion.
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12.0 RECORDKEEPING AND REPORTING
Comment: The commenter stated that most pilot flame
outages occur when emissions are not being routed to the
flare. Consequently, the commenter asserted the
requirements in section 63.487-5(d)(5)(ii)(E) for records of
the times and durations of these outages are inappropriate.
The commenter added that the General Provisions state that
failure to comply with "normal" requirements are not
violations if the startup, shutdown, malfunction plan is
followed. The commenter noted that these recordkeeping
requirements should suffice.
Response: The EPA agrees with the commenter, and has
included the suggestions in the final rule.
Comment: One commenter (IV-D-18) supported the
provision in section 63.486-5 (f) (2) (iv) of the proposed rule
that states if all monitored parameters are within the
required range, that fact may be recorded, and an average
value for the batch cycle would not have to be recorded.
The commenter also suggested that in that situation, they
should not be required to retain records of individual
recorded values.
Response: Compliance with the operating conditions is
based on the daily average value of continuously monitored
parameters. If all recorded values for a monitored
parameter during an operating day are within the defined
operating level established in the Notification of
Compliance Status or operating permit, the owner or operator
may record this fact and forego calculating a daily average
(or batch daily average) value. [Note: The final
elastomers rule requires an owner or operator to establish
and monitor operating parameter levels.]
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Comment: One coinmenter (IV-D-26) suggested that the
rule allow for manual recordkeeping, as is allowed under
section 63.151(g)(3) of the HON. These readings should be
allowed at four hour intervals when the control device
normally operates in steady-state, or, for batch operations,
they should occur during the peak loading conditions of a
batch cycle.
Response: The proposed and final rules allow non-
automated monitoring and recording systems that meet the
requirements specified in section 63.506(g)(2). These
provisions state that manual reading and recording of the
value of the relevant operating parameter must be performed
no less frequently than once per hour. These provisions are
identical to section 63.151(g)(3) of the HON. The decision
to retain the hourly timeframe and to not switch to four
hour intervals, as requested by the commenter, was made to
ensure consistency with the continuous monitoring
requirements requiring retention of hourly values for use in.
calculating the daily average.
Comment: One commenter (IV-D-18) requested that all
"universal" recordkeeping requirements should be eliminated
from the rule. The commenter defined these as instances
where the EPA requires records to be kept that demonstrate
routine compliance. Instead, the commenter stated that only
records demonstrating excursions/violations should be
required to be kept.
Response: Under section 114(a) of the Clean Air Act,
the EPA may require owners or operators to demonstrate that
each emission unit remains in compliance at all times. In
order to ensure such compliance, a means must exist for
verifying compliance on a continuous basis. Regulations
must, therefore, establish monitoring requirements that are
capable of determining continuous compliance with the
applicable standards. The EPA believes that the
recordkeeping and requirements of the final elastomers rule
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are necessary to show compliance with the rule. The EPA
will continue to require owners or operators to keep
records, regardless or whether there was an excursion or
not. These records are necessary to prove compliance, when
no excursion has occurred, and are used to determine the
severity of a violation, and, thus, how much of a penalty
should be assessed, when an excursion does occur. If an
excursion occurs, and no records have been kept regarding
the severity of the excursion, a maximum fine of up to
$25,000 per day per control device could be assessed.
The EPA has made every effort to reduce the
recordkeeping requirements of the final elastomers rule.
All of the provisions of the HON that reduce recordkeeping
for parameter monitoring of control devices have been
incorporated into this rule. In addition, the EPA reviewed
the recordkeeping required by the proposed rule and has made
even further reductions in the amount of information that is
required to be recorded. For instance, the final rule has
been changed to require recording and retention Of hourly
average values of continuously monitored values. The
proposed rule required calculation of 15-minute averages.
Under the proposed rule, if the daily average value was
above the minimum or below the maximum established levels
(i.e., excess emissions occurred), the 15-minute values had
to be retained; if the daily average value was within the
established level, the 15-minute values could be converted
to hourly averages and the hourly averages could be retained
instead of the 15-minute averages. Upon reconsideration,
the EPA found the proposed two-step process (of first
computing and recording 15-minute averages, and then being
allowed to convert them to hourly averages for record
retention) to be burdensome and unnecessary. Hourly average
values provide a sufficient record to support the
calculation of the daily average value of a parameter.
Therefore, to reduce the recordkeeping burden, the rule has
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been changed to specify that only hourly averages must be
retained for all days, regardless of whether or not excess
emissions occurred. The rule no longer requires recording
or retention of 15-minute average values.
For emission points where continuous parameter
monitoring is required, the value of the parameter must
still be measured at least once every 15 minutes, but only
an hourly average must be recorded and retained. Many
facilities already have computerized systems and monitor
parameters more frequently than once every 15 minutes for
process control purposes. The 15-minute monitoring
frequency is consistent with the General Provisions and
previous NSPS and NESHAP for emission points from similar
industries.
The final elastomers rule and the General Provisions
require records to be kept for five years, which is
consistent with the recordkeeping requirements of
section 70.6 of the operating permit program and other
NESHAP. Storage of records for more than five years would
be burdensome, and any compliance issues should be
identified within five years. Furthermore, the statute of
limitations for enforcement is five years so there is no
reason to keep records for a longer period of time.
Comment: Several commenters (IV-D-18 and IV-D-26)
stated that the reporting requirements in the proposed rule
were excessive. One commenter suggested that requirements
for all routine reports should be deleted, as the
information they provide is redundant with the annual
operating permit certification requirement. The other
commenter (IV-D-18) stated that the reporting provisions in
the rule should be significantly revised in order to reduce
burdens. Specifically, this commenter suggests that the EPA
eliminate any five of the reports required under the rule.
Barring elimination of these reports, the commenter
suggested that revisions be made to minimize burdens. For
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example, the cotnmenter stated that 63 .493 (b) (6) (iv) (A) be
revised to say that if a test report has already been sent
in under any rule, the source would not be required to send
in another one. The commenter suggested that the EPA review
the reports and eliminate reports where a small fraction of
the reports are never reviewed in detail by the enforcement
agency, or at least eliminate data elements that are seldom
reviewed. A third commenter (IV-D-16) stated that the
compliance-related reporting requirements should be deleted,
because the Title V permit certification assures facility
compliance.
Response: The periodic reporting system of semiannual
reporting is in conformance with section 70.5(c) of the
operating permits program, which states that facilities are
required to submit reports no less frequently than once
every six months. The operating permits program contains
monitoring, recordkeeping, and reporting requirements
minimally sufficient for a facility to verify compliance and
submit compliance certifications. The requirements in the
operating permit program serve as a baseline minimum for all
facilities subject to Title V. However, for facilities
subject to other federal standards (e.g., NESHAP), more
frequent or substantial monitoring, recordkeeping, and
reporting may be necessary to certify compliance.
Consequently, regulations developed under Title III,
including the elastomers rule, will incorporate additional
requirements that go beyond the minimal requirements
contained in the operating permits program. Facilities must
comply with only the most stringent requirements.
Therefore, duplicate records or reports are not required.
Comment: Two commenters (IV-D-18 and IV-D-8) noted
that section 63.493(b)(7)(i) requires sources to have a
startup, shutdown, and malfunction plan. They noted that
discussion of start up, shutdown, and malfunction plans also
appear in section 63.493(b), where the reports that must be
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submitted to the EPA are specified. They asserted that this
implies the startup, shutdown, malfunction plan must be
routinely submitted to the EPA. The commenters suggested
that the EPA clarify that routine submitting of the SSM plan
would not be required by the rule, and move this requirement
out of the reporting into the recordkeeping section of the
rule.
Response: The startup, shutdown, and malfunction plan
required by section 63.lO(d)(5) of subpart A is not required
to be submitted to the Administrator. The provisions of the
final rule have been changed to clarify that the startup,
shutdown, and malfunction plan should be kept onsite. If,
at any time, the startup, shutdown, and malfunction plan is
not followed, this should be described and reported in the
Periodic Report.
Comment: Three commenters (IV-D-10, IV-D-8 and IV-D-
26) disagreed with the SSM reporting provisions. The
commenters believe that the requirement in the proposed rule
for sources to report a deviation from the startup,
shutdown, and malfunction (SSM) plan within two hours is
unreasonable. The commenters also suggested that the EPA
should eliminate the requirement for periodic semiannual SSM
reports, and only exceptions reporting should be required.
Two of the commenters (IV-D-10 and IV-D-26) stated that
sources in compliance should only be required to maintain
records showing that no excursions occurred.
Response: If, at any time, the startup, shutdown, and
malfunction plan is not followed, this should be described
and reported in the Periodic Report.
With respect to the commenter's request to only
document and report deviations from the startup, shutdown,
and malfunction plan when they result in a violation, the
requirements in the final rule have not been changed. The
EPA believes that the documentation and reporting of all
deviations is necessary for the EPA to evaluate the adequacy
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of the startup, shutdown, and malfunction plan. Since the
owner or operator is allowed to add to the startup,
shutdown, malfunction plan as needed, deviations that occur
frequently can be added to the plan to avoid a repetitive
recordkeeping and reporting burden. Further, while a
specific deviation may not result in a violation, it could
be indicative of a problem that would eventually lead to a
violation.
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EPA Region 5 Library
U.S. Environmental Protection Agency
Region 5, Library (PL-12J)
77 West Jackson Boulevard, 12th Floor
Chicago, II 60604-3590
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