[Federal Register: October 6, 2008 (Volume 73, Number 194)]
[Proposed Rules]
[Page 58351-58385]
[DOCID:fr06oc08-23]

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Part IV

Environmental Protection Agency

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40 CFR Part 63

 National Emission Standards for Hazardous Air Pollutants for Chemical
Manufacturing Area Sources; Proposed Rule

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 63

[EPA-HQ-OAR-2008-0334; FRL-8720-8]
RIN 2060-AM19

National Emission Standards for Hazardous Air Pollutants for
Chemical Manufacturing Area Sources

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: EPA is proposing national emissions standards for hazardous
air pollutants for nine area source categories in the chemical
manufacturing sector: Agricultural Chemicals and Pesticides
Manufacturing, Cyclic Crude and Intermediate Production, Industrial
Inorganic Chemical Manufacturing, Industrial Organic Chemical
Manufacturing, Inorganic Pigments Manufacturing, Miscellaneous Organic
Chemical Manufacturing, Plastic Materials and Resins Manufacturing,
Pharmaceutical Production, and Synthetic Rubber Manufacturing. The
proposed standards and associated requirements for the nine area source
categories are combined in one subpart. The proposed emissions
standards for new and existing sources are based on EPA's determination
regarding the generally available control technology or management
practices for the nine area source categories. EPA is co-proposing an
alternative to the requirements for process vents emitting metal
hazardous air pollutants. The alternative would set a higher size
threshold for large metal hazardous air pollutant process vents.

DATES: Comments must be received on or before November 5, 2008, unless
a public hearing is requested by October 16, 2008. If a hearing is
requested on the proposed rule, written comments must be received by
November 20, 2008. Under the Paperwork Reduction Act, comments on the
information collection provisions must be received by the Office of
Management and Budget (OMB) on or before November 5, 2008.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-HQ-
OAR-2008-0334, by one of the following methods:
     http://www.regulations.gov: Follow the on-line
instructions for submitting comments.
     E-mail<EMAIL_ADDRESS>     Fax:<PHONE_NUMBER>.
     Mail: U.S. Postal Service: send comments to: National
Emission Standards for Hazardous Air Pollutants for Chemical
Manufacturing Area Sources Docket, Environmental Protection Agency, EPA
Docket Center, Mailcode: 2822T, 1200 Pennsylvania Ave., NW.,
Washington, DC 20460. Please include a total of two copies. We request
that a separate copy also be sent to the contact person identified
below (see FOR FURTHER INFORMATION CONTACT).
     Hand Delivery: In person or by courier, deliver comments
to: EPA Docket Center, Public Reading Room, EPA West Building, Room
3334, 1301 Constitution Ave., NW., Washington, DC 20004. Such
deliveries are only accepted during the Docket's normal hours of
operation, and special arrangements should be made for deliveries of
boxed information.
    Instructions: Direct your comments to Docket ID No. EPA-HQ-OAR-
2008-0334. EPA's policy is that all comments received will be included
in the public docket without change and may be made available online at
http://www.regulations.gov, including any personal information
provided, unless the comment includes information claimed to be
confidential business information (CBI) or other information whose
disclosure is restricted by statute. Do not submit information that you
consider to be CBI or otherwise protected through www.regulations.gov,
or e-mail. The www.regulations.gov Web site is an ``anonymous access''
system, which means EPA will not know your identity or contact
information unless you provide it in the body of your comment. If you
send an e-mail comment directly to EPA without going through
www.regulations.gov, your e-mail address will be automatically captured
and included as part of the comment that is placed in the public docket
and made available on the Internet. If you submit an electronic
comment, EPA recommends that you include your name and other contact
information in the body of your comment and with any disk or CD-ROM you
submit. If EPA cannot read your comment due to technical difficulties
and cannot contact you for clarification, EPA may not be able to
consider your comment. Electronic files should avoid the use of special
characters, any form of encryption, and be free of any defects or
viruses.
    Docket: All documents in the docket are listed in the
www.regulations.gov index. Although listed in the index, some
information is not publicly available, e.g., CBI or other information
whose disclosure is restricted by statute. Certain other material, such
as copyrighted material, will be publicly available only in hard copy
form. Publicly available docket materials are available either
electronically in http://www.regulations.gov or in hard copy at the
National Emission Standards for Hazardous Air Pollutants for Chemical
Manufacturing Area Sources Docket at the EPA Docket and Information
Center, EPA West, Room 3334, 1301 Constitution Ave., NW., Washington,
DC. The Public Reading Room is open from 8:30 a.m. to 4:30 p.m., Monday
through Friday, excluding legal holidays. The telephone number for the
Public Reading Room is<PHONE_NUMBER>, and the telephone number for the
Air Docket is<PHONE_NUMBER>.

FOR FURTHER INFORMATION CONTACT: Mr. Randy McDonald, Office of Air
Quality Planning and Standards, Sector Policies and Programs Division,
Coatings and Chemicals Group (E143-01), Environmental Protection
Agency, Research Triangle Park, North Carolina 27711, telephone number:
(919) 541-5402; fax number:<PHONE_NUMBER>; e-mail address:
<EMAIL_ADDRESS>
SUPPLEMENTARY INFORMATION: Outline. The information in this preamble is
organized as follows:

I. General Information
    A. Does this action apply to me?
    B. What should I consider as I prepare my comments to EPA?
    C. Where can I get a copy of this document?
    D. When would a public hearing occur?
II. Background Information for the Proposed Area Source Standards
    A. What is the statutory authority and regulatory approach for
the proposed standards?
    B. What area source categories are affected by the proposed
standards?
    C. How did we gather information for this proposed standard?
    D. What are the production processes, emission points, and
available controls?
III. Summary of the Proposed Standards
    A. Do the proposed standards apply to my source?
    B. When must I comply with the proposed standards?
    C. What are the proposed emissions standards?
    D. What are the initial and continuous compliance requirements?
    E. What are the notification, recordkeeping, and reporting
requirements?
IV. Rationale for This Proposed Rule
    A. How did we subcategorize emission sources?
    B. How did we determine GACT?
    C. How did we select compliance requirements?
    D. Why did we decide to exempt these area source categories from
title V permitting requirements?
V. Impacts of the Proposed Standards
    A. What are the air impacts?
    B. What are the cost impacts?
    C. What are the economic impacts?
    D. What are the non-air health, environmental, and energy
impacts?

VI. Statutory and Executive Order Reviews
    A. Executive Order 12866: Regulatory Planning and Review
    B. Paperwork Reduction Act
    C. Regulatory Flexibility Act
    D. Unfunded Mandates Reform Act
    E. Executive Order 13132: Federalism
    F. Executive Order 13175
    G. Executive Order 13045: Protection of Children from
Environmental Health and Safety Risks
    H. Executive Order 13211: Actions Concerning Regulations That
Significantly Affect Energy Supply, Distribution, or Use
    I. National Technology Transfer Advancement Act
    J. Executive Order 12898: Federal Actions to Address
Environmental Justice in Minority Populations and Low-Income
Populations

I. General Information

A. Does this action apply to me?

    The regulated categories and entities potentially affected by this
proposed action are shown in the table below. This proposed rule
applies to chemical manufacturing operations at any of nine chemical
manufacturing area source categories that process, use, produce, or
generate any of the following hazardous air pollutants (HAP): 1,3-
butadiene; 1,3-dichloropropene; acetaldehyde; chloroform; ethylene
dichloride; methylene chloride; hexachlorobenzene; hydrazine;
quinoline; or compounds of arsenic, cadmium, chromium, lead, manganese,
or nickel. If the proposed standards are applicable to a chemical
manufacturing area source, the standards apply to all organic HAP
emissions and all metal HAP emissions from all chemical manufacturing
operations at the area source. The proposed standards do not apply to
hydrogen halide and halogen HAP (i.e., hydrogen chloride, chlorine, and
hydrogen fluoride) at affected sources,\1\ except when these HAP are
generated in combustion-based emission control devices that are used to
meet the proposed standards for organic HAP. For additional information
about applicability provisions, see section III.A of this preamble.
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    \1\ The affected source is the chemical manufacturing operations
at area sources in one of the nine source categories subject to this
proposed rule. Chemical manufacturing operations include all process
equipment and activities that process, use, produce, or generate any
of the HAP listed in Table 1 of this subpart. Chemical manufacturing
operations also includes all storage tanks, transfer racks, cooling
tower systems, wastewater systems, and equipment associated with the
production of chemicals at an area source subject to the proposed
rule.

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                                 NAICS
      Industry category         code \1\  Examples of regulated entities
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Chemical manufacturing.......        325  Chemical manufacturing area
                                           sources that process, use, or
                                           produce any of the HAP
                                           subject to this subpart
                                           except for: (1) Production
                                           operations classified in
                                           NAICS 325222, 325314, or
                                           325413; (2) production
                                           operations subject to
                                           standards for other listed
                                           area source categories \2\ in
                                           NAICS 325; (3) certain
                                           fabricating operations; (4)
                                           manufacture of photographic
                                           film, paper, and plate where
                                           material is coated or
                                           contains chemicals (only the
                                           manufacture of the
                                           photographic chemicals would
                                           be regulated); and (5)
                                           manufacture of radioactive
                                           elements or isotopes, radium
                                           chloride, radium luminous
                                           compounds, strontium, and
                                           uranium.
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\1\ North American Industry Classification System.
\2\ All of the other source categories in NAICS 325 for which other
  standards apply are: Acrylic Fibers/Modacrylic Fibers Production,
  Chemical Preparation, Carbon Black, Chemical Manufacturing: Chromium
  Compounds, Polyvinyl Chloride and Copolymers Production, Paint and
  Allied Coatings, and Mercury Cell Chlor-Alkali Manufacturing.

    Area sources in NAICS 325 not specifically identified in the chart
above are affected by this action. To determine whether your chemical
manufacturing area source would be regulated by this action, you should
examine the applicability criteria in 40 CFR 63.11494 of subpart VVVVVV
(NESHAP for Chemical Manufacturing Area Sources). If you have any
questions regarding the applicability of this action to a particular
entity, consult either the air permit authority for the entity or your
EPA regional representative as listed in 40 CFR 63.13 of subpart A
(General Provisions).

B. What should I consider as I prepare my comments to EPA?

    Do not submit information containing CBI to EPA through
www.regulations.gov or e-mail. Send or deliver information identified
as CBI only to the following address: Roberto Morales, OAQPS Document
Control Officer (C404-02), Office of Air Quality Planning and
Standards, Environmental Protection Agency, Research Triangle Park,
North Carolina 27711, Attention Docket ID EPA-HQ-OAR-2008-0334. Clearly
mark the part or all of the information that you claim to be CBI. For
CBI information in a disk or CD-ROM that you mail to EPA, mark the
outside of the disk or CD-ROM as CBI and then identify electronically
within the disk or CD-ROM the specific information that is claimed as
CBI. In addition to one complete version of the comment that includes
information claimed as CBI, a copy of the comment that does not contain
the information claimed as CBI must be submitted for inclusion in the
public docket. Information so marked will not be disclosed except in
accordance with procedures set forth in 40 CFR part 2.

C. Where can I get a copy of this document?

    In addition to being available in the docket, an electronic copy of
this proposed action will also be available on the Worldwide Web (WWW)
through the Technology Transfer Network (TTN). Following signature, a
copy of this proposed action will be posted on the TTN's policy and
guidance page for newly proposed or promulgated rules at the following
address: http://www.epa.gov/ttn/oarpg/. The TTN provides information
and technology exchange in various areas of air pollution control.

D. When would a public hearing occur?

    If anyone contacts EPA requesting to speak at a public hearing
concerning the proposed rule by October 16, 2008, we will hold a public
hearing on October 21, 2008. If you are interested in attending the
public hearing, contact Ms. Janet Eck at<PHONE_NUMBER> to verify that
a hearing will be held. If a public hearing is held, it will be held at
10 a.m. at the EPA's Environmental Research Center Auditorium, Research
Triangle Park, NC, or an alternate site nearby.

II. Background Information for the Proposed Area Source Standards

A. What is the statutory authority and regulatory approach for the
proposed standards?

    Section 112(d) of the Clean Air Act (CAA) requires EPA to establish
national emission standards for hazardous air pollutants (NESHAP) for
both major and area sources of HAP that are listed for regulation under
CAA section 112(c). A major source emits or

has the potential to emit 10 tons per year (tpy) or more of any single
HAP or 25 tpy or more of any combination of HAP. An area source is a
stationary source that is not a major source.
    Section 112(k)(3)(B) of the CAA calls for EPA to identify at least
30 HAP that, as a result of emissions of area sources, pose the
greatest threat to public health in the largest number of urban areas.
EPA implemented this provision in 1999 in the Integrated Urban Air
Toxics Strategy (64 FR 38715, July 19, 1999). Specifically, in the
Strategy, EPA identified 30 HAP that pose the greatest potential health
threat in urban areas, and these HAP are referred to as the ``30 urban
HAP.'' Section 112(c)(3) requires EPA to list sufficient categories or
subcategories of area sources to ensure that area sources representing
90 percent of the emissions of the 30 urban HAP are subject to
regulation. We implemented these requirements through the Integrated
Urban Air Toxics Strategy (64 FR 38715, July 19, 1999). A primary goal
of the Strategy is to achieve a 75 percent reduction in cancer
incidence attributable to HAP emitted from stationary sources.
    Under CAA section 112(d)(5), we may elect to promulgate standards
or requirements for area sources ``which provide for the use of
generally available control technologies or management practices by
such sources to reduce emissions of hazardous air pollutants.''
Additional information on generally available control technologies or
management practices (GACT) is found in the Senate report on the
legislation (Senate report Number 101-228, December 20, 1989), which
describes GACT as:

    * * * methods, practices and techniques which are commercially
available and appropriate for application by the sources in the
category considering economic impacts and the technical capabilities
of the firms to operate and maintain the emissions control systems.

Consistent with the legislative history, we can consider costs and
economic impacts in determining GACT, which is particularly important
when developing regulations for source categories, like this one, that
have many small businesses.
    Determining what constitutes GACT involves considering the control
technologies and management practices that are generally available to
the area sources in the source category. We also consider the standards
applicable to major sources in the same industrial sector to determine
if the control technologies and management practices are transferable
and generally available to area sources. In appropriate circumstances,
we may also consider technologies and practices at area and major
sources in similar categories to determine whether such technologies
and practices could be considered generally available for the area
source category at issue. Finally, as we have already noted, in
determining GACT for a particular area source category, we consider the
costs and economic impacts of available control technologies and
management practices on that category.
    We are proposing these national emission standards in response to a
court-ordered deadline that requires EPA to issue standards for 10 area
source categories listed pursuant to section 112(c)(3) and (k) by
December 15, 2008 (Sierra Club v. Johnson, no. 01-1537, D.D.C., March
2006). As part of our effort to meet this deadline, we are proposing in
this action the NESHAP for the nine area source categories that are
described in section II.B of this preamble. Another rulemaking will
include standards for the remaining source category that is due in
December 2008.

B. What area source categories are affected by the proposed standards?

    This proposed NESHAP affects chemical manufacturing operations at
nine area source categories: (1) Agricultural Chemicals and Pesticides
Manufacturing; (2) Cyclic Crude and Intermediate Production; (3)
Industrial Inorganic Chemical Manufacturing; (4) Industrial Organic
Chemical Manufacturing; (5) Inorganic Pigments Manufacturing; (6)
Miscellaneous Organic Chemical Manufacturing; (7) Plastic Materials and
Resins Manufacturing; (8) Pharmaceutical Production; and (9) Synthetic
Rubber Manufacturing. The inclusion of each of these source categories
on the section 112(c)(3) area source category list is based on 1990
emissions data, as EPA used 1990 as the baseline year for that listing.
In this preamble and proposed rule we refer to the nine source
categories collectively as chemical manufacturing area sources.
Descriptions of the nine source categories are as follows:
    Agricultural Chemicals and Pesticides Manufacturing. The
agricultural chemicals and pesticides manufacturing source category is
designated by NAICS codes 325311 (nitrogenous fertilizer
manufacturing), 325312 (phosphatic fertilizer manufacturing), and
325320 (pesticide and other agricultural chemical manufacturing).
Products of this industry include nitrogenous and phosphatic fertilizer
materials including anhydrous ammonia, nitric acid, ammonium nitrate,
ammonium sulfate, urea, phosphoric acid, superphosphates, ammonium
phosphates, and calcium metaphosphates. The source category also
includes the formulation and preparation of ready-to-use agricultural
and household pest control chemicals from technical chemicals or
concentrates, the production of concentrates which require further
processing before use as agricultural pesticides, and the manufacturing
or formulating of other agricultural chemicals such as minor or trace
elements and soil conditioners.
    Organic Chemical Production. The cyclic crude and intermediate
production, industrial organic chemical manufacturing, and
miscellaneous organic chemical manufacturing source categories are
discussed collectively because there is considerable overlap in the
NAICS codes that apply to these source categories. These source
categories are designated by NAICS codes 32511 (petrochemical
manufacturing), 325132 (synthetic organic dye and pigment
manufacturing), 32519 (other basic organic chemical manufacturing),
325221 (cellulosic organic fiber manufacturing), and 3256 (soap,
cleaning compound, and toilet preparation manufacturing). The source
category also includes organic gases designated by NAICS code 325120
(industrial gas manufacturing), and it includes production of chemicals
such as explosives and photographic chemicals designated by NAICS code
3259 (other chemical product and preparation manufacturing).
    Raw materials for this industry include, for example, refined
petroleum chemicals, coal tars, and wood. The industry manufactures a
wide variety of final products as well as numerous chemicals that are
used as feedstocks to produce these final products and products in
other chemical manufacturing source categories. Examples of types of
products include solvents, organic dyes and pigments, plasticizers,
alcohols, detergents, and flavorings.
    Industrial Inorganic Chemical Manufacturing. The industrial
inorganic chemical manufacturing source category includes manufacturing
of inorganic gases that are designated by NAICS code 325120 (industrial
gas manufacturing), manufacturing of inorganic dyes that are designated
by NAICS code 325131 (inorganic dye and pigment manufacturing), and
most manufacturing designated by NAICS code 32518 (other basic
inorganic chemical manufacturing). Exceptions to

production designated by NAICS code 32518 include carbon black and
mercury cell chlor-alkali production, which are separate source
categories.
    Inorganic Pigment Manufacturing. Inorganic pigments are part of
NAICS code 325131 (Inorganic Dye and Pigment Manufacturing). The
majority of inorganic pigments are oxides, sulfides, oxide hydroxides,
silicates, sulfates, or carbonates that normally consist of single
component particles.
    The inorganic pigment manufacturing processes can generally be
divided between those that use partial combustion and those that use
pure pyrolysis. Inorganic pigments generally are used to impart colors
to a variety of compounds. They may also impart properties of rust
inhibition, rigidity, and abrasion resistance. Inorganic pigments are
generally insoluble and remain unchanged physically and chemically when
mixed with a carrier.
    Pigment manufacturers supply inorganic colors in a variety of forms
including powders, pastes, granules, slurries, and suspensions.
Pigments are used in the manufacture of paints and stains, printing
inks, plastics, synthetic textiles, paper, cosmetics, contact lenses,
soaps, detergents, wax, modeling clay, chalks, crayons, artists'
colors, concrete, masonry products, and ceramics.
    Pharmaceutical Production. The pharmaceutical manufacturing source
category consists of chemical production operations that produce drugs
and medication. These operations include chemical synthesis (deriving a
drug's active ingredient) and chemical formulation (producing a drug in
its final form). The source category is designated by NAICS codes
325411 (medicinal and botanical manufacturing), 325412 (pharmaceutical
preparation manufacturing), and 325414 (biological product, except
diagnostic, manufacturing).
    Plastic Materials and Resins Manufacturing. This source category is
designated by NAICS code 325211 (plastics material and resin
manufacturing). Examples of products in this source category include
epoxy resins, nylon resins, phenolic resins, polyesters, polyethylene
resins, and styrene resins. The source category does not include
polyvinyl chloride and copolymers production, which is a separate
source category.
    Synthetic Rubber Manufacturing. The synthetic rubber manufacturing
source category is designated by NAICS code 325212 (synthetic rubber
manufacturing). Facilities in this source category manufacture
synthetic rubber or vulcanizable elastomers by polymerization or
copolymerization. For this source category, an elastomer is defined as
a rubber-like material capable of vulcanization, such as copolymers of
butadiene and styrene, copolymers of butadiene and acrylonitrile,
polybutadienes, chloroprene rubbers, and isobutylene-isoprene
copolymers.
    We listed Cyclic Crude and Intermediate Production, Industrial
Inorganic Chemical Manufacturing, Industrial Organic Chemical
Manufacturing, Plastic Materials and Resins Manufacturing, and
Synthetic Rubber Manufacturing as area source categories under CAA
section 112(c)(3) as part of the 1999 Integrated Urban Strategy (64 FR
38721, July 19, 1999). On June 26, 2002, we amended the area source
category list by adding source categories, including Agricultural
Chemicals and Pesticides Manufacturing, Miscellaneous Organic Chemical
Manufacturing, and Pharmaceutical Production (67 FR 43112, 43113). On
November 22, 2002, we added Inorganic Pigments Manufacturing to the
area source category list (67 FR 70427, 70428). These nine area source
categories encompass nearly all of the chemical manufacturing industry
described in NAICS 325.
    The urban HAP that must be regulated at chemical manufacturing area
sources to achieve the section 112(c)(3) requirement to regulate 90
percent of urban HAP are:

 1,3-butadiene                       methylene chloride
 1,3-dichloropropene                 hexachlorobenzene
 acetaldehyde                        hydrazine
 chloroform                          quinoline
 ethylene dichloride                 HAP metals:
                                             compounds of arsenic,
                                             cadmium, chromium, lead,
                                             manganese, and nickel

These urban HAP are hereafter collectively referred to as the
``chemical manufacturing urban HAP''. The organic HAP and hydrazine,
which is controlled in the same manner as the organic HAP, are
hereafter referred to as the ``chemical manufacturing organic urban
HAP''. The metal HAP are hereafter referred to as the ``chemical
manufacturing metal urban HAP.''
    Based on information in the National Emissions Inventory (NEI), the
Toxics Release Inventory (TRI), and other supplemental information, we
estimate that about 1,700 facilities are chemical manufacturing area
sources. Approximately 450 of these area sources emit at least one of
the chemical manufacturing urban HAP. We estimate that, collectively,
the chemical manufacturing area sources emit about 450 tpy of the
chemical manufacturing organic urban HAP (including 0.4 tpy of
hydrazine) and 51 tpy of the chemical manufacturing metal urban HAP.
Total organic and metal HAP emissions from the 450 chemical
manufacturing area sources that emit any of the chemical manufacturing
urban HAP are estimated to be about 1,450 tons/yr.

C. How did we gather information for this proposed standard?

    We gathered information for this proposed rule from the 2002 NEI,
the 2002 and 2004 TRI; company Web sites, published literature, and
current State and Federal regulations.
    We developed an initial list of area sources in these categories
based on facilities in the 2002 NEI database that were designated as
area sources and classified with any of the SIC codes for chemical
manufacturing. We added facilities classified as major sources in the
NEI database to the list of area sources if reported emissions were
much less than major source threshold, and no other information was
available to confirm the facility as a major source. We also reviewed
the TRI database and we identified facilities classified with any of
the chemical manufacturing standard industrial classification (SIC)
codes that had emissions less than half the major source thresholds and
added these facilities to the list of area sources if they were not
also listed in the NEI database. We also removed facilities from the
list based on information from permits, company Web sites, and other
available resources that showed a facility was closed, did not
manufacture chemicals, or is a major source already subject to MACT
standards.
    Emission records in the NEI database were determined to be
applicable to chemical manufacturing operations if the source
classification code (SCC) was specific to one of the chemical
manufacturing industries (e.g., pharmaceuticals manufacturing). We
considered other records to be applicable if the SIC code or the NEI
database MACT code was applicable for the chemical manufacturing
industry, and the SCC was not clearly for non-chemical manufacturing
operations such as external combustion or solvent cold cleaners.
    We found that many of the records in the NEI could not be readily
assigned to one of the six types of emission points subject to the
proposed rule. Therefore, to estimate emissions by emission point we
used only the total organic HAP emissions and total metal HAP

emissions (and corresponding urban HAP fractions) for each facility. We
then disaggregated the total organic HAP emissions per facility to
process vents, storage tanks, equipment leaks, and wastewater systems
assuming the average distribution for major sources also applies to
area sources. We estimated organic HAP emissions from transfer
operations and cooling towers separately.
    Although emissions from transfer operations may have been included
in the NEI data, information from major sources indicates that these
emissions are small relative to emissions from the other emission
points. Furthermore, many chemical manufacturing facilities do not ship
liquids containing organic HAP by rail or tank truck. Therefore, we
determined it was simpler to estimate emissions from transfer
operations separately. To estimate these emissions, we assumed half of
the area sources that emit organic HAP have transfer operations and
used the model transfer racks that were developed for facilities that
are subject to the National Emission Standards for Organic Hazardous
Air Pollutants From the Synthetic Organic Chemical Manufacturing
Industry (SOCMI) for Process Vents, Storage Vessels, Transfer
Operations, and Wastewater, commonly known as the ``hazardous organic
NESHAP'' (HON) in 40 CFR part 63, subpart G. Because the estimated
emissions are so small, the impact of adding them to the NEI emissions
estimate of nationwide emissions from the source category is
negligible.
    Few NEI records were clearly for cooling towers, and most of those
focused on chlorine emissions, presumably from the use of biocides.
Organic HAP emissions from cooling towers occur only as a result of a
malfunction in heat exchange equipment that allows process fluid to
leak into the recirculating cooling water and then volatilize as the
contaminated water falls through the cooling tower. Because the
emissions are the result of malfunctions, we assumed that they are not
included in the NEI. Most area sources also are not monitoring cooling
tower systems for leaks. However, if operation at area sources is
similar to operation at major sources, it is likely that cooling tower
systems are a significant source of organic HAP emissions. Therefore,
we estimated emissions from cooling tower systems based on typical
recirculation rates for cooling towers at chemical manufacturing
sources and assumed leak frequencies and concentrations.
    We assumed metal HAP are emitted only from process vents. These
emissions may be in either vapor or particulate form depending on the
temperature of the unit operation. They are not emitted from other
emission points because emissions from other emission points depend
largely on evaporation of the pollutant. As metal-based compounds have
very low vapor pressures, they are unlikely to be emitted in
significant amounts from other emission points.
    We reviewed State and other Federal regulations that apply to the
area and major sources in the source categories for information to
establish subcategories and control requirements for some of the
emission points. For example, the new source performance standards
(NSPS) for volatile organic liquid storage vessels in 40 CFR part 60,
subpart Kb apply to storage tanks at some area sources. Similarly, a
regulation established by the Texas Commission on Environmental Quality
which requires monitoring of recirculating water in cooling tower
systems, also applies to some area sources. We also reviewed standards
for other source categories that would be appropriate for and
transferable to operations at chemical manufacturing area sources as
well. For example, we determined that management practices applicable
to gasoline loading racks at gasoline distribution area sources are
equally feasible for transfer operations at chemical manufacturing area
sources.

D. What are the production processes, emission points, and available
controls?

    The chemical manufacturing industry produces a wide variety of
chemicals using processes that involve numerous types of unit
operations. Example operations include reaction, mixing, fermentation,
extraction, distillation, crystallization, washing, filtering, drying,
grinding, and calcining. Pollutants are emitted from these operations
through process vents. Process vent emissions are generated from a
variety of activities including equipment vessel purges with air or
nitrogen, vapor displacement due to filling a vessel with liquid, gas
evolution from reactions, applying a vacuum to a vessel, heating the
contents of a vessel, depressurizing a vessel, and drying a solid
product. The proposed rule would regulate three types of process vents:
Continuous process vents; batch process vents; and metal HAP process
vents. Pollutants are also emitted from five other types of equipment
that are associated with or support a process: Storage tanks, cooling
tower systems, equipment leaks, transfer operations, and wastewater
systems. Each of the types of emission points and potential controls
are described in the following sections.
    Continuous process vents. A continuous process vent is defined as
the point of discharge to the atmosphere (or the point of entry into a
control device, if any) of a gas stream that meets three conditions:
(1) It contains organic HAP, (2) some or all of the gas stream
originates from a unit operation that operates continuously, and (3)
the gas stream flow is continuous. Typical controls include add-on
control devices such as thermal incinerators, condensers, and carbon
adsorbers.
    Batch process vents. A batch process vent is defined as a point of
discharge from a single unit operation or from a common header that
connects multiple unit operations through which an organic HAP-
containing gas stream is, or has the potential to be, released to the
atmosphere. Specifically excluded from the proposed definition of a
batch process vent are continuous process vents and any other emission
points that are subject to other standards in the proposed rule (e.g.,
a storage tank or wastewater treatment unit), gas streams routed to a
fuel gas system, and certain elephant trunk systems. Typical controls
include add-on control devices such as thermal incinerators,
condensers, and carbon adsorbers.
    Metal HAP process vents. A metal HAP process vent is defined as the
point of discharge to the atmosphere (or inlet to a control device, if
any) of a metal HAP-containing gas stream from any unit operation in
chemical manufacturing operations at an affected source. If both metal
HAP and organic HAP are emitted, a metal HAP process vent may also be a
continuous process vent or batch process vent. Typical controls include
add-on control devices that control particulate matter (PM), such as
fabric filters and electrostatic precipitators.
    Storage tank. A storage tank is a tank or other vessel that is used
to store organic or inorganic HAP that are used in or produced by the
chemical manufacturing operations, except for the following: Vessels
permanently attached to motor vehicles, pressure vessels, vessels
storing organic liquids that contain HAP only as impurities, wastewater
storage tanks, and process tanks. Primary uses of storage tanks are to
store raw materials, products, and wastes. Bottoms receivers and surge
control vessels are also considered to be storage tanks. Emissions from
storage tanks occur as a result of vapor displacement when the tank is
being filled and as a result of vapor expansion due to diurnal
temperature changes. Numerous controls are available for

storage tanks. These include the use of internal or external floating
roofs, vapor balancing to the tank truck or other vessel from which the
storage tank is filled, and routing emissions through a closed-vent
system to a control device such as a thermal incinerator.
    Cooling tower systems. Cooling towers are used to cool warm water
from heat exchangers that is then recirculated to the heat exchangers.
Process fluid that leaks into the recirculating water in the heat
exchanger may be volatilized and emitted to the atmosphere in the
cooling tower. Controls generally involve a monitoring program to
identify elevated levels of organic compounds or a surrogate for the
organic compounds in the recirculating water. When a leak is detected,
the defect in the heat exchanger must be repaired to eliminate the leak
and the emissions.
    Equipment Leaks. Equipment leaks occur from pumps, the packing
around valve stems in valves, flanges and connectors that are not
tight, pressure relief valves, open-ended lines, and sampling
connections. For pumps, valves, and connectors, controls consist of
leak detection and repair (LDAR) programs in which the equipment is
inspected on a specified schedule. The inspections may be either
sensory-based or instrument-based. The programs also define a leak
differently, but all require repair of detected leaks. Controls for
other types of equipment usually involve the use of certain types of
equipment. For example, open-ended lines must be capped, and pressure
relief devices must be equipped with rupture disks or connected to a
closed-vent system that routes releases to a control device such as a
flare.
    Transfer operations. Transfer operations are defined as the loading
into tank trucks and rail cars of organic liquids that contain one or
more organic HAP, as defined in Section 112(b) of the CAA, from a
loading rack (also known as a transfer rack) at an affected source. A
loading rack is the system used to fill tank trucks and rail cars at a
single geographic site and includes the associated pumps, meters,
shutoff valves, relief valves, and other piping and valves. One widely
used emission control technique is submerged loading, which consists of
either filling through a drop tube that extends from the top of the
vessel being loaded to within a few inches of the bottom of the vessel
or by bottom loading through a built-in fill connection near the bottom
of the vessel. Another available control is vapor balancing, which
routes displaced vapors from the tank truck or railcar back to the
storage tank from which it is being loaded. Routing displaced vapors
through a closed-vent system to a control device is another option.
    Wastewater systems. Wastewater is defined as water that contains at
least one of the 76 organic HAP listed in Table 9 of 40 CFR part 63,
subpart G, and is discarded from a chemical manufacturing process or
control device, except for the following: (1) Stormwater from
segregated sewers; (2) water from fire-fighting and deluge systems,
including testing of such systems; (3) spills; (4) water from safety
showers; (5) samples of a size not greater than reasonably necessary
for the method of analysis that is used; (6) equipment leaks; (7)
wastewater drips from procedures such as disconnecting hoses after
cleaning lines; and (8) noncontact cooling water. Wastewater includes
both process wastewater and maintenance wastewater. Process wastewater
is wastewater which, during manufacturing or processing, comes into
direct contact with or results from the production or use of any raw
material, intermediate product, finished product, by-product, or waste
product. Maintenance wastewater is wastewater that is generated by the
draining of process fluid from components in a chemical manufacturing
process into an individual drain system prior to or during maintenance
activities. A wastewater system is the equipment in which the
wastewater is conveyed and treated. Aerobic biological treatment to
degrade the organic compounds is the most common type of treatment.
Other types of treatment that remove organics include anaerobic
biological treatment, incineration of the wastewater, and steam or air
stripping followed by condensation or other techniques to recover or
destroy the stripped compounds. Controls also include some form of
emission suppression techniques between the discharge from the process
and the treatment unit. Examples of emission suppression include water
seals on individual drains, covers on junction boxes and holding or
treatment tanks, and closed sewer lines. Some regulations also prohibit
the discharge of multi-phase wastewater streams; these streams must be
separated into a water layer and one or more organic layers by gravity
separation techniques, and only the water phase may be discharged to
the wastewater system.

III. Summary of the Proposed Standards

A. Do the proposed standards apply to my source?

    This proposed NESHAP applies to each existing or new facility that
is an area source of HAP and has chemical manufacturing operations that
process, use, produce, or generate any of the 15 chemical manufacturing
urban HAP. Chemical manufacturing operations would be defined as the
facility-wide collection of chemical manufacturing processing equipment
and associated storage tanks, cooling tower systems, transfer
operations, and wastewater systems. The chemical manufacturing
operations are the affected source.
    The nine chemical manufacturing area source categories include most
of the source categories that are classified under NAICS 325. The
proposed rule, therefore, specifies applicability based on all chemical
manufacturing operations that are used to produce chemicals classified
under NAICS 325 except as described below. We believe this approach is
more straightforward than listing all of the processes or NAICS codes
that are subject because it is a more concise list, it ensures that no
processes are inadvertently left off the list, and it automatically
applies to new processes developed in the future. Manufacturing
operations classified by NAICS codes 325222, 325314, and 325413 are not
subject to this proposal because these operations were not included in
the listing of source categories as part of the Urban Strategy. The
proposal does not apply to mercury cell chlor-alkali plants, chemical
preparations, paint and allied products, polyvinyl chloride and
copolymers production, carbon black, chemical manufacturing: chromium
compounds, and acrylic and modacrylic fibers production, because those
area source categories are subject to other section 112(d) NESHAP. In
addition, specific manufacturing processes or chemical processes that
are not subject to the proposed rule include:
    (1) Manufacture of radioactive elements or isotopes, radium
chloride, radium luminous compounds, strontium, and uranium;
    (2) Manufacture of photographic film, paper, and plate where the
material is coated with or contains chemicals;
    (3) Fabricating operations (such as spinning or compressing a solid
polymer into its end use); compounding operations (in which blending,
melting, and resolidifying of a solid polymer product occur for the
purpose of incorporating additives, colorants, or stabilizers);
extrusion and drawing operations (converting an already produced solid
polymer into a different shape by melting or mixing the polymer and
then forcing it or pulling it through an orifice to create an extruded
product) are generally not subject to this proposal. Such operations
are subject if

they involve processing with a HAP solvent or if an intended purpose of
the operation is to remove residual HAP monomer;
    (4) Research and development facilities as defined in section
112(c)(7) of the CAA;
    (5) Quality assurance/quality control laboratories;
    (6) Boilers and incinerators (not used to comply with emission
standards in the proposed rule), chillers and other refrigerator
systems, and other equipment and activities that are not directly
involved (i.e., they operate within a closed system and materials are
not combined with process fluids) in the processing of raw materials or
the manufacturing of a product or intermediates used in production of
the product are not considered chemical manufacturing operations. The
above operations are not covered by this rule because they were not
part of the inventory on which we based the listing for the nine area
source categories at issue in this rule.
    To be subject to the proposed standards, the chemical manufacturing
operations also must process, use, produce, or generate any of the 15
chemical manufacturing urban HAP. If the proposed standards are
applicable to a chemical manufacturing area source, the proposed
standards apply to all organic HAP emissions and all metal HAP
emissions from chemical manufacturing operations at the area source. We
are proposing that the standards for each type of emission point apply
to all of the emission points of that type in an affected source,
including those that do not emit a chemical manufacturing urban HAP
(e.g., an area source may have two storage tanks, one containing
methanol and the other containing methylene chloride, and, under the
proposed rule, both would be part of the affected source and subject to
the storage tank standards).
    We recognize that standards limited to the emission points that
emit the chemical manufacturing urban HAP at the nine area source
categories would be sufficient to satisfy the requirement in section
112(c)(3) and (k)(3)(B), that EPA regulate sufficient source categories
to account for 90 percent of the urban HAP emissions. However, section
112 of the CAA does not prohibit the Agency from regulating other HAP
emitted from area sources listed pursuant to section 112(c)(3). Section
112(d)(5) states that for area sources listed pursuant to section
112(c), the Administrator may, in lieu of section 112(d)(2) ``MACT''
standards, promulgate standards or requirements ``applicable to
sources'' which provide for the use of GACT or management practices
``to reduce emissions of hazardous air pollutants.'' This provision
does not limit the Agency's authority to regulating only those urban
HAP emissions for which the category is needed to achieve the 90
percent requirement in section 112(c)(3).
    We are proposing to apply the standards in this manner for several
reasons. The management practices proposed in the rule are equally
effective at controlling emissions of HAP other than the chemical
manufacturing urban HAP and there is little, if any, additional cost
for implementing those management practices for all emissions sources
(e.g., for process vents the annual cost of the management practices is
less than $300/yr). In addition, where add-on controls are required
under this rule, those controls will reduce not only emissions of the
chemical manufacturing HAP, but also emissions of the organic and metal
HAP that are not chemical manufacturing urban HAP. Applying the
proposed standards only to the chemical manufacturing urban HAP would
require the facility to speciate HAP as opposed to measuring total HAP
when demonstrating compliance. Furthermore, many facilities route
emissions from process vessels to common vents and it would not be
practical to control only urban HAP emissions from those vents. We are
also proposing to apply the standard to all HAP because many of the
area sources emit a significant amount of HAP in addition to the
chemical manufacturing urban HAP (for example, the nationwide ratio of
total organic HAP to chemical manufacturing organic HAP at affected
sources is more than 3:1), and all HAP are hazardous to human health
and the environment.
    We have determined that sources will not have to install different
controls or implement different management practices to implement the
proposed standards for all HAP and, as part of the GACT analysis, we
have found that the costs of applying the proposed standards to all HAP
are reasonable. For all of these reasons, we propose to apply these
standards to all chemical manufacturing operations at the chemical
manufacturing area source. We request comment on the environmental,
cost, and economic impacts of this approach.
    Controlling halogenated HAP emissions by burning in a combustion
device, as the proposed rule provides, will generate hydrogen halide
and halogen HAP. Several NESHAP (40 CFR part 63, subparts G, GGG, MMM,
and FFFF) require control of hydrogen halide and halogen HAP when a
combustion device is used to control halogenated vent streams. The
proposed standards apply to hydrogen halide and halogen HAP (i.e.,
hydrogen chloride, chlorine, and hydrogen fluoride), but only when they
are generated in a combustion device that is used to meet a proposed
standard. The proposed controls for the chemical manufacturing urban
HAP generally would achieve little or no co-control of the hydrogen
halide and halogen HAP. Simply converting one HAP to another does not
protect human health or the environment. Therefore, these by-products
of combustion are also subject to proposed standards.

B. When must I comply with the proposed standards?

    Some facilities will have to design, purchase, and install add-on
control equipment to meet the proposed requirements. We are therefore
proposing that owners or operators of existing sources comply with all
the requirements of the area source NESHAP by 3 years after the date of
publication of the final rule in the Federal Register. A new affected
source would be required to comply by the date of publication of the
final rule in the Federal Register or upon initial startup, whichever
is later.
    Area sources subject to the rule would not be required to obtain a
title V operating permit. Our reasons for exempting chemical
manufacturing area sources from the requirement to obtain a title V
permit are discussed in section IV.D of this preamble.

C. What are the proposed emissions standards?

    We are proposing management practices as GACT for all process
vents, storage tanks, equipment leaks, transfer operations, and cooling
tower systems. For specified subcategories, we are proposing management
practices and emissions limitations or other requirements as GACT for
continuous process vents, batch process vents, metal HAP process vents,
cooling tower systems, and storage tanks. We are proposing emission
standards that consist of two treatment requirements for one
subcategory of wastewater streams, and we are proposing a single
treatment requirement for a second subcategory of wastewater streams.
All of the proposed standards are the same for new and existing
affected sources.
1. Continuous Process Vents
    As explained in section IV.A, we distinguished continuous process
vents

based on a total resource effectiveness (TRE) index value of 1, which
we believe is a reasonable proxy for the size of the vent.
Specifically, we created two subcategories for continuous process
vents: Those continuous process vents with a TRE value less than or
equal to one and those with a TRE greater than one. The TRE is a
measure of HAP emissions and control costs and is normalized to a value
of 1.0 for a cost-effectiveness of $3,000 per ton of HAP reduction.
Facilities would determine the TRE index value either at the point of
discharge to the atmosphere or after the last recovery device using
procedures specified in 40 CFR 63.115 of the HON.
    We are proposing that owners and operators implement management
practices for all continuous process vents. The management practices
consist of requirements to check the integrity of the process equipment
once per quarter, to repair process equipment as necessary to eliminate
leaks, and to operate the process equipment with all openings or access
points covered or with closure mechanisms in the closed position,
except as necessary for operator access. If a leak is detected, the
owner or operator would be required to repair it within 15 calendar
days of detection, unless a reasonable justification for delay exists
and is documented. The owner or operator must provide notification of a
delay in repair in the semiannual report. These management practices
are the only proposed emission requirements for the subcategory of
continuous process vents with a TRE value greater than 1.
    For the subcategory of continuous process vents with a TRE value
less than or equal to 1, we are proposing that the owner or operator
reduce emissions of organic HAP (including hydrazine) by 95 percent by
weight or greater or to 20 parts per million by volume (ppmv) or less.
Because flares achieve greater than 95 percent reduction, the owner or
operator may reduce emissions of organic HAP by routing emissions
through a closed vent system to a flare. However, the proposed rule
does not allow a flare to be used to control halogenated emission
streams. As an alternative to demonstrating compliance with the
standards specified above, the proposed rule allows an owner or
operator to comply with the alternative standard in 40 CFR part 63,
subpart FFFF (i.e., the miscellaneous organic NESHAP [MON]). Under the
alternative standard, an owner or operator would be required to route
the process vent streams through a closed vent system to a control
device that meets a specified outlet concentration and demonstrate
compliance using a continuous emission monitoring system (CEMS). For a
combustion device, the proposed rule requires that organic HAP
emissions be reduced to an outlet concentration of 20 ppmv measured as
total organic compounds (TOC), and hydrogen halide or halogen HAP
generated in the combustion device be reduced to an outlet
concentration of 20 ppmv or less. For a noncombustion device, organic
HAP would be reduced to an outlet concentration of 50 ppmv or less
measured as total organic HAP. In the MON, this alternative is allowed
for both continuous process vents and batch process vents and is
equivalent to the 98 percent control requirement in the MON. The same
alternative standard is in the NESHAP for pharmaceuticals production
and pesticide active ingredient production (40 CFR part 63, subparts
GGG and MMM).
2. Batch Process Vents
    As explained in section IV.A, we considered the different sizes and
types of batch process vents in chemical manufacturing operations and
established subcategories based on annual emissions to reflect the
combined factors. Specifically, we created two subcategories for batch
process vents: Those batch process vents that emit 19,000 lb/yr or
greater of organic HAP and those that emit less than 19,000 lb/yr of
organic HAP. Facilities would determine annual emissions using test
data or procedures in subparts GGG and FFFF of part 63 or estimating
emissions based on the emissions for the worst-case batch process.
    We are proposing that owners and operators implement management
practices for all batch process vents. The management practices consist
of requirements to check the integrity of the process equipment once
per quarter, to repair process equipment as necessary to eliminate
leaks, and to operate the process equipment with all openings or access
points covered or with closure mechanisms in the closed position,
except as necessary for operator access. If a leak is detected, the
owner or operator would be required to repair it within 15 calendar
days of detection, unless a reasonable justification for delay exists
and is documented. The owner or operator must provide notification of a
delay in repair in the semiannual report. These management practices
are the only proposed emission requirements for the subcategory of
batch process vents emitting less than 19,000 lb/yr of organic HAP.
    In addition to the management practices applicable to both
subcategories, we are proposing for the subcategory of batch process
vents with total uncontrolled organic HAP emissions equal to or greater
than 19,000 lb/yr that the owner or operator either: (1) Reduce the
collective uncontrolled organic HAP emissions (including hydrazine)
from the sum of all batch process vents within the chemical
manufacturing operations by 90 percent by weight or greater or to 20
ppmv or less; (2) route emissions from batch process vents containing
at least 90 percent of the uncontrolled total organic HAP through a
closed vent system to a flare (except for halogenated vent streams); or
(3) comply with combinations of the requirements in items 1 and 2 for
different groups of batch process vents. As an alternative, the
proposed rule allows an owner or operator to comply with the
alternative standard as described in section III.C.1 of this preamble.
These alternatives provide equivalent levels of emission control.
    Facilities would estimate the sum of the typical uncontrolled
organic HAP emissions for all emission episodes using equations and
other procedures specified in 40 CFR part 63, subpart FFFF and the
National Emission Standards for Pharmaceuticals Production (40 CFR part
63, subpart GGG). The proposed rule includes 3 alternatives to the
requirement to estimate batch process vent emissions from each process.
First, although actual emissions may vary from one batch to another for
a given process, the proposed rule allows the owner or operator to
estimate emissions for a typical batch and assume those emissions apply
to each batch. Second, as an alternative to estimating emissions for a
standard batch of each process, the proposed rule allows the owner or
operator to determine emissions only for a typical batch in the process
that has the highest emissions and assume that those emissions apply to
batches in all other processes. Process knowledge, engineering
assessment, or test data may be used to identify the worst case
process. Third, if an owner or operator can demonstrate that organic
HAP usage is less than 19,000 lb/yr and this is the only HAP in the
process, then HAP emissions also must be less than 19,000 lb/yr. Thus,
the proposed rule does not require an owner or operator to estimate
emissions if this condition is met.
3. Metal HAP Process Vents
    As explained in section IV.A, we considered the different sizes and
types of metal HAP process vents in chemical

manufacturing operations and established subcategories based on annual
emissions of metal HAP to reflect the combined factors. Specifically,
we created two subcategories for metal HAP process vents based on a
threshold level of emissions: Those metal HAP process vents that emit
above the threshold as one subcategory and below the threshold as a
second subcategory. We are co-proposing alternative process vent
thresholds of 100 lb/yr and 400 lb/yr of metal HAP. Facilities would
determine the mass metal HAP emissions rate by using process knowledge,
engineering assessments, or test data.
    We are proposing that owners and operators implement management
practices for all metal HAP process vents. The management practices
consist of requirements to check the integrity of the process equipment
once per quarter, to repair process equipment as necessary to eliminate
leaks, and to operate the process equipment with all openings or access
points covered or with closure mechanisms in the closed position,
except as necessary for operator access. If a leak is detected, the
owner or operator would be required to repair it within 15 calendar
days of detection, unless a reasonable justification for delay exists
and is documented. The owner or operator must provide notification of a
delay in repair in the semiannual report. These management practices
are the only proposed emission requirements for the subcategory of
metal HAP process vents emitting below the threshold (less than 100 lb/
yr or 400 lb/yr of metal HAP).
    In addition to the management practices applicable to both
subcategories, we are proposing for the subcategory with total
uncontrolled metal HAP emissions from metal HAP process vents equal to
or greater the threshold (100 lb/yr or 400 lb/yr of metal HAP) that the
owner or operator reduce uncontrolled emissions of metal HAP by 95
percent by weight or greater.
    To determine whether the percent reduction requirement applies, the
owner or operator would be required to determine and sum the emissions
from all of the metal HAP process vents. The proposed rule allows the
use of process knowledge, engineering assessment, or test data to
determine the mass emission rate.
4. Storage Tanks
    As explained in section IV.A, we considered the different sizes of
storage tanks and subcategorized on that basis. Specifically, we
created two subcategories for storage tanks: Large storage tanks are
those that meet the size and maximum true vapor pressure (MTVP)
thresholds for control in the NSPS for volatile organic liquid storage
vessels in 40 CFR part 60, subpart Kb, and small storage tanks are
those that do not meet the subpart Kb thresholds.
    We are proposing that owners and operators implement management
practices for all storage tanks that store organic HAP. The management
practices consist of requirements to check the integrity of the storage
tanks once per quarter, to repair tanks as necessary to eliminate
leaks, and to operate the tanks with all openings or access points
covered or with closure mechanisms in the closed position, except as
necessary for operator access. If a leak is detected, the owner or
operator would be required to repair it within 15 calendar days of
detection, unless a reasonable justification for delay exists and is
documented. The owner or operator must provide notification of a delay
in repair in the semiannual report. These management practices are the
only proposed emission requirements for the subcategory of small
storage tanks.
    In addition to the management practices applicable to both
subcategories, we propose that for the subcategory of large storage
tanks that owners and operators comply with the control requirements in
subpart Kb. The control options in 40 CFR part 60, subpart Kb are to
operate and maintain a fixed roof in combination with an internal
floating roof, use an external floating roof, or to route emissions
through a closed vent system to a control device that reduces organic
HAP emissions by 95 percent or greater.
5. Cooling Tower Systems
    We are proposing that owners and operators implement management
practices for all cooling tower systems in which recirculating water is
used in heat exchangers to cool process fluid that contains organic
HAP. We are proposing a management practice for a subcategory of small
cooling tower systems and an emission limit for a subcategory of large
cooling tower systems.
    For the subcategory of small cooling tower systems, those with
recirculating water flow rates less than 8,000 gal/min, we are
proposing that the owner or operator inspect the cooling water system
quarterly for hydrocarbon odor, discolored water, or other evidence of
hydrocarbons in the cooling water. In addition, the owner or operator
would be required to prepare and operate in accordance with an
operating and maintenance plan that describes actions to be taken in
response to different inspection results. If a leak is detected, the
owner or operator would be required to repair it (or remove the leaking
heat exchanger from service) within 45 calendar days of detection,
unless a reasonable justification for delay exists and is documented.
The owner or operator must provide notification of a delay in repair in
the semiannual report.
    For the subcategory of large cooling tower systems, those with
recirculating water rates of 8,000 gal/min or greater, we are proposing
that the owner or operator monitor the recirculating cooling water
using a surrogate indicator of heat exchange system leaks as required
in Sec.  63.104(c) and (d) of the HON (40 CFR part 63, subpart F).
These provisions would require the owner or operator to prepare and
operate in accordance with a monitoring plan that documents the
procedures that will be used to detect leaks of process fluids into the
cooling water. The types of information to include in the plan would
include a description of the parameter(s) to be monitored, rationale
for why the selected parameter(s) will reliably indicate a leak, and
the level that indicates a leak. When a leak is detected, the owner or
operator would be required to repair it (or remove the leaking heat
exchanger from service) within 45 calendar days of detection, unless
delay of repair is allowed. Delay of repair would be allowed until the
next shutdown if the owner or operator documents that emissions from
shutdown for repair would cause greater emissions than estimated
emissions from allowing the system to continue leaking until the
scheduled shutdown.
6. Equipment Leaks
    We are proposing that each owner or operator implement management
practices for equipment leaks. The management practices consist of
quarterly leak inspections of all equipment in organic HAP service. The
term ``equipment'' applies to each pump, compressor, agitator, pressure
relief device, sampling connection system, open ended valve or line,
connector, and instrumentation system in chemical manufacturing
operations. To be in organic HAP service, the equipment must either
contain or contact a fluid (liquid or gas) that contains one or more of
the organic HAP listed in or pursuant to section 112 of the CAA. Leak
detection methods using sight, sound, and smell may be used. Under the
proposed rule, repair or replacement of leaking equipment is required
within 15 days after detection, or the reason for any delay of repair
must be documented. The owner or

operator must provide notification of a delay in repair in the
semiannual report.
7. Transfer Operations
    We are proposing that each owner or operator of an affected source
implement management practices for all transfer operations that involve
transfer of material that contains organic HAP. We are proposing that
each owner or operator implement management practices to minimize
evaporation, clean up spills, and implement submerged loading. The
proposed rule defines submerged loading as the use of a submerged fill
pipe that discharges no more than 12 inches from the bottom of the
cargo tank.
8. Wastewater Systems
    We developed two subcategories of wastewater streams based on
differences in the concentration of partially soluble HAP in the
wastewater stream. One subcategory consists of wastewater streams with
partially soluble HAP concentrations less than 10,000 parts per million
by weight (ppmw), and the other consists of wastewater streams with
concentrations equal to or greater than 10,000 ppmw. Partially soluble
HAP are a subset of all organic HAP. They are less soluble in water
than other organic HAP, and they are more easily separated from water.
A list of partially soluble HAP that matches a list of partially
soluble HAP in the MON is included in Table 3 of the proposed rule. The
proposed rule requires an owner or operator to use any of the
procedures in 40 CFR 63.144(b) of the HON to determine the partially
soluble HAP concentration in each wastewater stream. Several options
are allowed. For example, the owner or operator may calculate the
concentration based on knowledge of the wastewater, using bench-scale
or pilot-scale test data that is demonstrated to be representative of
the actual wastewater, or by testing samples of the actual wastewater
stream.
    For both subcategories we are proposing that the owner or operator
treat the wastewater onsite or discharge it to an offsite facility for
treatment. In addition, for the subcategory of wastewater streams with
partially soluble HAP concentrations equal to or greater than 10,000
ppmw, we are proposing that the owner or operator separate the stream
into a water phase and one or more organic phases using a decanter or
other equipment that operates on the principle of gravity separation.
The water phase would then have to be treated as described above. The
separated organic liquid may be sent back to the process or discarded
as hazardous waste. Also, liquid waste from the process that consists
only of organic compounds may not be sent to the wastewater system if
any of the organic compounds in the wastewater stream are partially
soluble HAP.

D. What are the initial and continuous compliance requirements?

1. Continuous Process Vents
    To demonstrate compliance with the management practices for
continuous process vents, the owner or operator would conduct quarterly
inspections during process operation to determine the integrity of the
process vessels, identify and repair within 15 days any leaks, and
ensure that covers are in place or closure mechanisms are in the closed
position during process operation.
    The proposed rule incorporates by reference the initial and
continuous compliance requirements in 40 CFR part 63 subparts SS and
FFFF for control devices, recovery devices, and closed-vent systems
used to meet the emission limit for continuous process vents. These
procedures are summarized below.
    For each non-flare control device used to meet the percent
reduction or outlet concentration emission limit for organic HAP
emissions from continuous process vents, the owner or operator would be
required to conduct a performance test to demonstrate initial
compliance. The performance test would be conducted under
representative operating conditions. To demonstrate continuous
compliance, the owner or operator would monitor applicable operating
parameters for the selected control device (including hydrogen halide
and halogen HAP control devices if control of a halogenated organic HAP
is achieved using a combustion device).
    For each flare, the owner or operator would conduct a flare
compliance assessment to demonstrate initial compliance, and
continuously monitor applicable operating parameters to demonstrate
continuous compliance.
    Continuous monitoring of applicable operating parameters is
required if a recovery device is used to maintain the TRE index value
at a level greater than 1.0 and less than or equal to 4.0.
    The owner or operator would inspect for and repair leaks in each
closed-vent system that is used to convey a gas stream from a
continuous process vent to either a final recovery device or control
device. Monitoring of bypass lines to identify periods when emissions
are diverted from a control device or recovery device would also be
required.
    Whenever a performance test is required, the owner or operator may
choose to submit the results of a prior performance test to demonstrate
initial compliance provided the prior test meets specified criteria.
For example, the test must have been conducted within the past 5 years
using the methods and procedures specified in the rule. Moreover, the
owner or operator must demonstrate either that no process changes have
been made since the test or that the results of the test with or
without adjustments, reliably demonstrate compliance with the
applicable emission standard despite process changes. Provisions are
included in the proposed rule for submitting prior written notification
of intent to use the previous data.
2. Batch Process Vents
    To demonstrate compliance with the management practices for batch
process vents, the owner or operator would conduct quarterly
inspections during process operation to determine the integrity of the
process vessels, identify and repair within 15 days any leaks, and
ensure that covers are in place or closure mechanisms are in the closed
position during process operation.
    The proposed rule incorporates by reference the initial and
continuous compliance requirements in 40 CFR part 63 subparts SS and
FFFF for control devices and closed-vent systems used to meet an
emission limit for batch process vents. These procedures are summarized
below.
    For each non-flare control device used to meet the percent
reduction or outlet concentration emission limit for batch process
vents, the owner or operator would conduct either a performance test or
a design evaluation to demonstrate initial compliance. The performance
test or design evaluation would be conducted under worst-case
conditions according to 40 CFR 63.1257(b)(8). The results of a previous
performance test may be used under the same conditions described in
section III.D.1 of this preamble for a previous performance test of
continuous process vents. To demonstrate continuous compliance, the
owner or operator would continuously monitor applicable operating
parameters for the selected control device (including hydrogen halide
and halogen HAP control devices if a halogenated organic HAP is
controlled using a combustion device).
    For each flare, the owner or operator would conduct a flare
compliance assessment to demonstrate initial compliance, and
continuously monitor applicable operating parameters to demonstrate
continuous compliance.

    The owner or operator would inspect for and repair leaks in each
closed-vent system that is used to convey a gas stream from a batch
process vent to a control device. Monitoring of bypass lines to
identify periods when emissions are diverted from a control device
would also be required.
3. Metal HAP Process Vents
    To demonstrate compliance with the management practices for metal
HAP process vents, the owner or operator would conduct quarterly
inspections during process operation to determine the integrity of the
process vessels, identify and repair within 15 days any leaks, and
ensure that covers are in place or closure mechanisms are in the closed
position during process operation.
    The proposed rule incorporates by reference the requirements of the
NESHAP for Chemical Manufacturing Area Sources: Chromium Compounds (40
CFR part 63, subpart NNNNNN), concerning the procedures to demonstrate
initial and continuous compliance with the percent reduction option for
metal HAP process vents at new affected sources. A modified version of
these requirements would apply to existing affected sources as
summarized below.
    A performance test would be required for both new and existing
affected sources to demonstrate initial compliance. Although subpart
NNNNNN requires only outlet testing, this proposed rule specifies that
the testing must be conducted at both the inlet and outlet of the
control device to determine the percent reduction. The results of a
previous performance test may be used under the same conditions
described in section III.D.1 of this preamble for a previous
performance test of continuous process vents.
    To demonstrate continuous compliance with an emission limit, the
owner or operator of a new affected source that uses a fabric filter to
control metal HAP emissions would install, operate, and maintain a bag
leak detection system in accordance with a site-specific monitoring
plan. The proposed rule specifies that the monitoring plan must
describe the operation, maintenance, quality assurance, recordkeeping,
and corrective action procedures to be followed.
    The owner or operator of a new affected source using any other type
of control device for PM, would demonstrate continuous compliance with
an emission limit by developing and operating in accordance with a
site-specific monitoring plan for that type of control device. The same
requirements would apply to the owner or operator of an existing
affected source using any type of control device for PM. The proposed
rule specifies that the monitoring plan would list the operating
parameters that will be monitored to maintain continuous compliance
with the emission limit, the operating limit for each parameter, and an
operation and maintenance plan for the control device and continuous
monitoring system. A preventive maintenance schedule consistent with
the manufacturer's instructions for routine and long-term maintenance
would be required as part of the operation and maintenance plan for the
control device.
4. Storage Tanks
    To demonstrate compliance with the management practices, the owner
or operator would conduct quarterly inspections to determine the
integrity of the tank, identify and repair within 15 days any leaks,
and ensure that any openings or access points are covered or closed.
    To demonstrate compliance with a floating roof or control device
standard for storage tanks, the proposed rule requires the owner or
operator to comply with procedures specified in 40 CFR part 63, subpart
Kb. For example, floating roofs must meet design specifications, and
the owner or operator would be required to conduct inspections, measure
seal gaps, and repair defects. For a control device, the owner or
operator would be required to demonstrate that the control device will
achieve the required control efficiency during maximum loading
conditions. The operating plan must also describe the parameter or
parameters to be monitored to demonstrate continuous compliance.
5. Cooling Tower Systems
    To demonstrate initial compliance with management practices for
cooling tower systems with recirculation rates less than 8,000 gal/min
(i.e., inspect the cooling water quarterly for evidence of hydrocarbons
in the cooling water), the owner or operator would be required to
prepare an operating and maintenance plan that describes actions to be
taken in response to different inspection results. If a leak is
identified, the owner or operator is required to fix it within 45 days.
Records documenting the occurrence of each inspection, the findings,
and any actions taken in response to those findings would demonstrate
ongoing compliance.
    To demonstrate initial compliance with the management practices for
cooling tower systems with recirculation rates equal to or greater than
8,000 gal/min (i.e., monitor for surrogate indicators of leaks), the
proposed rule requires the owner or operator to develop a site-specific
monitoring plan. The plan would include a description of the parameter
or condition to be monitored and explain how the monitoring will
reliably indicate the presence of leaks. To demonstrate continuous
compliance, the owner or operator would conduct monitoring at least
every calendar quarter and fix leaks within 45 days of detection,
unless the owner or operator meets specified conditions under which
delay of repair is allowed. The plan would not need to be submitted to
the Administrator for approval, but the proposed rule requires that the
plan be revised any time a leak is identified by means other than those
in the plan and could not be detected by the procedures described in
the plan. Except for the monitoring frequency in the first six months
after the compliance date, the initial and continuous compliance
requirements in the proposed rule are the same as the provisions of
Sec.  63.104(c) through (e) of the HON (40 CFR part 63, subpart F).
6. Equipment Leaks
    To demonstrate compliance with the requirement to conduct quarterly
inspections for equipment leaks, the owner or operator would be
required to document the date and results of each inspection in a log
book. The number and location of any leaks, the date of repair, and
reasons for any delay of repair beyond 15 calendar days after detection
of the leak also would be recorded in the log.
7. Transfer Operations
    To demonstrate compliance with standards for transfer operations,
the owner or operator would document that the transfer rack is designed
to use top loading with a drop tube that extends to within 12 inches of
the bottom of the vessel being loaded and/or that it can fill tank
trucks and railcars by bottom loading. Alternatively, the owner or
operator would document that emissions from transfer operations are
controlled by vapor balancing back to the storage tank from which the
tank truck or railcar is loaded or that emissions are routed through a
closed-vent system to a control device.
8. Wastewater Systems
    Compliance with the standard requiring treatment of process and
maintenance wastewater is a requirement to provide notice of any

deviation from this requirement in the semiannual compliance reports.
For wastewater streams that contain partially soluble HAP at
concentrations equal to or greater than 10,000 ppmw, the owner or
operator would be required to maintain records to demonstrate that the
organic and water phases have been separated before discharging the
water phase for treatment and document the disposition of the organic
phase.

E. What are the notification, recordkeeping, and reporting
requirements?

1. Notifications and Reports
    The owner or operator would be required to comply with all of the
NESHAP General Provisions (40 CFR part 63, subpart A), for
notifications; startup, shutdown, and malfunction (SSM) plans and
reports; and reporting. If performance tests are required under the
proposed rule, then the notification and reporting requirements for
performance tests in the General Provisions would also apply. We have
identified in Table 4 to the proposed NESHAP the General Provisions of
40 CFR part 63 applicable to affected sources. An additional
notification for the use of a previous performance test to demonstrate
compliance with the applicable emission limit for batch process vents,
continuous process vents, or metal HAP process vents would also be
required.
    Each owner or operator would be required to submit a notification
of compliance status report, as required by Sec.  63.9(h) of the
General Provisions. Reporting requirements incorporated by reference
may specify additional information to include in the notification of
compliance status report. Finally, the proposed rule requires the owner
or operator to include in the notification of compliance status report
certifications of compliance with rule requirements.
    Semiannual compliance reports, as required by Sec.  63.10(e)(3) of
subpart A, would be required only for semiannual reporting periods when
a deviation from any of the requirements in the rule occurred; the
delay of repair provisions were invoked for heat exchangers in a
cooling tower system; there is a delay of repair for an equipment leak,
process vessel leak, storage tank leak, or leak from a small cooling
tower; or any process changes occurred and compliance certifications
were reevaluated.
2. Recordkeeping
    The proposed rule requires records to demonstrate compliance with
each management practice, emissions control requirement or other
standard. These recordkeeping requirements are specified either
directly in 40 CFR part 63, subpart VVVVVV, in the General Provisions
to 40 CFR part 63, or other rules in which provisions have been
incorporated by reference. These other rules include 40 CFR part 63
subpart F (cooling towers), subpart G (wastewater), subpart SS
(continuous process vents, batch process vents, and closed vent
systems), subpart GGG (alternative standard), subpart FFFF (alternative
standard), and subpart NNNNNN (metal HAP process vents). In addition,
the proposed rule incorporates by reference the recordkeeping
requirements in 40 CFR part 60, subpart Kb (storage tanks).
    Records for management practices applicable for all process vents
must be maintained. Specifically, the owner or operator must keep
records of the dates and the results of each inspection and the dates
of equipment repairs.
    The owner or operator would be required to keep records of each
calculation that shows the TRE for a continuous process vent is greater
than 1.0. This requirement would apply to both initial calculations and
calculations after process or operational changes. Records of either
continuously monitored parameter data or CEMS data (if complying with
the alternative standard) would be required for a control device or a
recovery device if a recovery device is used to maintain the TRE
between 1.0 and 4.0.
    Each owner and operator of batch process vents would be required to
keep a record of the initial calculation of either the total annual
emissions from batch process vents or the total annual HAP usage that
is used to determine the applicable subcategory. If emissions are
calculated, the proposed rule requires the owner or operator to keep
records of the initial estimates of typical emissions per batch for
each process and to track the number of batches of each process
operated per month. If the applicable subcategory is determined based
on HAP usage, then the proposed rule requires the owner or operator to
track the HAP usage per month. Other information that the owner or
operator would be required to record includes: (1) Revised estimates of
the collective emissions from all batch process vents in the chemical
manufacturing operations if process changes occur (or revised estimates
of the HAP usage, if applicable); and (2) the information and
procedures used to identify the worst-case process if the owner or
operator elects to estimate emissions for all batch process vents based
on the emissions for the worst case process.
    Each owner or operator of metal HAP process vents would be required
to keep records of the initial calculation of estimated metal HAP
annual emissions from all metal process vents. The owner or operator of
each affected source that is subject to the emission limit for metal
HAP emissions would be required to keep a current copy of the
monitoring plan. If a fabric filter is used to meet the emission limit
for metal HAP emissions at a new affected source, the owner or operator
would be required to keep records of the bag leak detection system
output, adjustments to the bag leak detection system, and information
related to alarms and corrective action. If a control device other than
a fabric filter is used at a new affected source to meet the emission
limit for metal HAP emissions, then the owner or operator would be
required to record continuously monitored operating parameters in
accordance with the site-specific monitoring plan. The proposed rule
also requires the owner of an existing source that is subject to the
emission limit for metal HAP to keep records of continuously monitored
operating parameters in accordance with the site-specific monitoring
plan.
    If an owner or operator is required to control a large storage tank
in accordance with 40 CFR part 60, subpart Kb, the owner or operator
would keep records related to the size of the tank and/or type of
material stored for each storage tank. In addition, if an internal
floating roof is installed to meet the standard, the owner or operator
would maintain records of each inspection of the roof and seals. If an
external floating roof is used to meet the standard, the owner or
operator would maintain records of seal gap measurements. If emissions
are routed through a closed vent system to a non-flare control device,
the owner or operator would maintain records of monitored operating
parameters. If the control device is a flare, records of all periods
during which the flare pilot flame is absent would be required. For
large and small storage tanks, records for management practices must be
maintained. Specifically, the owner or operator must keep records of
the dates and the results of each inspection and the dates of equipment
repairs.
    To comply with the surrogate indicator monitoring standard for
large cooling towers, the proposed rule requires the owner or operator
to keep records of the monitoring data and information related to the
detection and repair of leaks. Maintaining a copy of the monitoring
plan would also be

required. For small cooling towers, facilities must inspect the cooling
tower water for evidence of the presence of hydrocarbons and record in
a log book the date and results of each quarterly inspection, including
description of leak; reasons for any delay of repair; and the date each
leak is repaired.
    Each owner or operator with equipment in organic HAP service would
be required to record in a log book the date and results of each
quarterly inspection, including the number of leaks and their
locations; reasons for any delay of repair beyond 15 days; and the date
each leak is repaired.
    Each owner or operator would be required to keep records
identifying all wastewater streams with total partially soluble HAP
concentrations greater than 10,000 ppmw and the disposition of all
organic phases generated in decanters or other separation equipment.
    All facilities must keep records of any deviations from the
requirements in the rule, and these records must be included in the
compliance report for the semiannual period in which the deviation
occurred.
    Typically, records would be retained for at least 5 years, but
records of storage tank dimensions and capacity would be retained for
the life of the affected source. In addition, monitoring plans,
operating and maintenance plans, and other plans would be updated as
necessary and kept for as long as they are still current.

IV. Rationale for This Proposed Rule

A. How did we subcategorize emission sources?

    As part of the development of these proposed standards, we
considered whether there were differences in processes, sizes, or other
factors affecting emissions that would warrant subcategorization. Under
section 112(d)(1) of the CAA, EPA ``may distinguish among classes,
types, and sizes within a source category or subcategory in
establishing such standards * * *.'' We explain below in detail our
proposed subcategorizations for six of the eight types of emission
points at chemical manufacturing area sources. We are proposing a
single subcategory for both equipment leaks and transfer operations.
    Continuous Process Vents. In numerous previous NSPS and NESHAP (40
CFR part 60 subparts III, NNN, and RRR, and 40 CFR part 63 subpart G)
rulemakings we have used the TRE equal to 1.0 as a basis for
distinguishing continuous process vents. The TRE combines the effect of
HAP emission rate, HAP heating value, and emission stream flow rate
into a single criterion that is easier to use than all of the
individual parameters. We determined from our review of the MON
database that continuous process vents with low TRE values tend to have
both higher emission stream flow rates and higher emission rates than
continuous process vents with higher TREs. Increased flow from a vent
generally corresponds with increased size of the unit operation and
increased production rate. For these reasons, we think that the TRE
value provides a reasonable estimate of the size of continuous process
units at chemical manufacturing area sources.
    After determining that the TRE value provides a reasonable
indicator of size, we reviewed the data to determine the appropriate
TRE value to propose to distinguish large and small continuous process
vents. We evaluated the impacts of requiring all continuous process
vents to operate add-on controls such as flares or condensers. We also
considered the impacts of requiring controls for continuous process
vents with different TRE values. We concluded that the control cost
increased at a significantly higher rate than the emissions reductions
the higher the TRE value. We also considered the TRE values at which
the various MACT and NSPS determine applicability. This is relevant to
the size of the continuous process vents because MACT standards apply
to major sources and NSPS standards may consider size in determining
applicability. We then considered the costs of control for the
different TRE values in other standards. For example, we determined
that the HON TRE value of 1 has a cost-effectiveness of approximately
$3000/ton of HAP removed and that the MON TRE value of 1.9 has a cost-
effectiveness of $7400/ton of HAP removed. In light of the relative
emissions reductions and costs for the various thresholds, we
determined that the TRE value of 1 was appropriate threshold to
distinguish between large and small continuous process vents at
chemical manufacturing area source.
    For all the reasons above, we are proposing to develop two
subcategories for continuous process vents based on differences in TRE
values. We are proposing this because TRE value provides a reasonable
basis on which to differentiate the size of continuous process vents.
One subcategory is for continuous process vents with a TRE value less
than or equal to 1.0, and the other is for continuous process vents
with a TRE value greater than 1.0. We solicit comments on whether
additional characteristics of continuous process vents would support
alternative subcategories based on size, class or type.
    Batch Process Vents. We determined after review of information for
batch process vents that many of the facilities with the highest
organic HAP emissions are emitting methylene chloride. Many of these
facilities are also emitting other HAP such as methanol, hexane, and
toluene. All of these HAP are typically used as solvents. In addition,
as part of various NESHAP rulemakings (40 CFR part 63, subparts GGG,
MMM, and FFFF), we determined that processes using HAP as solvents
generally have emissions much higher than other processes that use HAP
as a reactant or generate HAP as a byproduct of reaction. This is the
case because process vent emissions are proportional to HAP
concentration in the vent stream, and the high vapor pressure solvents
result in a high concentration of HAP in the gas phase. The high-volume
use of solvents also results in higher emissions because of
displacement losses.
    Another factor that affects the emissions level is the production
rate. For chemicals manufactured using batch processes, production rate
is measured by number of batches. The proposed rule references standard
equations for calculating HAP emissions from unit operations typically
used in batch chemical processing. The annual emissions from
manufacturing a chemical using batch processes is equal to the
emissions from a standard batch cycle multiplied by the number of
batches run in a year.
    Based on this analysis, we have determined that operations where
solvent use constitutes the primary source of HAP emissions and the
number of batches at affected facilities is high, there are higher
organic HAP emissions. We have concluded that these factors relating to
the type of operation (high solvent use) and size of operation (based
on number of batches) provide a reasonable basis for subcategorization.
We considered whether we should combine these factors into a formula
for defining the subcategories, but given the various variables at
issue, we determined such an approach was too complex. As an
alternative, we evaluated the sources in the category and determined
that annual emissions rate provides a means of considering the factors
discussed above. Also, as discussed above in regard to continuous
process vents, we considered the relative emissions reductions and
costs for the area sources in the category in determining the
appropriate emissions level at which to subcategorize the batch process
vents.

    Specifically, we propose that facilities with organic HAP emissions
greater than 19,000 lb/yr from batch process vents tend to have both
high solvent use and a large number of batches. We are therefore
proposing two subcategories based on the difference in annual
emissions, one subcategory is for batch process vents with emissions
equal to or greater than 19,000 lb/yr, and the other is for batch
process vents with emissions less than 19,000 lb/yr. We solicit
comments on our proposed subcategorization and whether additional
characteristics of batch process vents would support alternative
subcategories based on size, class or type.
    Metal HAP Process Vents. In our review of data for metal HAP
process vents, we determined that the level of metal HAP emissions from
the vents is a function of the purpose for which the metal HAP is
present in the process. Specifically, emissions varied according to
whether the metal HAPs were intended to be incorporated into the
product of the chemical manufacturing process. For products that
incorporate the metal HAP (e.g., manganese dioxide, inorganic pigments,
catalysts), emissions of metal HAP are generally larger; conversely,
the metal HAP emissions tend to be smaller when the metal HAP is
present because it is from impurities introduced with raw materials or
products of combustion. However, we have identified some vents that
emit larger amounts of metal HAP, even though the metal HAP is not
incorporated into the final product. These facilities are likely to
emit more metal HAP because of the large size of the facility or
because the facility is using raw materials and/or fuel with higher
levels of metal HAP impurities.
    For these reasons, we are not subcategorizing metal HAP process
vents solely on the basis of whether or not the processes are the type
that incorporate metal HAP into the final product, as that would not
account for the facilities that do not incorporate the metal HAP into
the product, but that are large facilities and thus have higher metal
HAP emissions, or those that use raw materials and fuel that have a
higher metal HAP content. We determined that it was appropriate to base
the subcategory on the amount of emissions of metal HAP from the
process vents as a proxy for the type and size of the vent. In
determining the appropriate emissions level, we considered relative
emissions reductions and costs to the affected area sources.
    We are co-proposing two subcategories for metal HAP process vents
based on either an emission level of 100 lb/yr or an emission level of
400 lb/yr. We think that at either level the proposed subcategorization
accounts for the purpose for which the metal HAP emissions are present
in the metal HAP process vents, the size of the facilities that
incorporate metal HAP into the product, the size of facilities that do
not incorporate metal into the final product, and the facilities that
do not incorporate the metal HAP into the product but use raw materials
or fuels that have high metal HAP content. By considering all these
factors in our subcategorization determination and also the relative
emissions reductions and cost of controls, we believe that we have
developed a reasonable basis on which to subcategorize metal HAP
process vents. We solicit comments, along with supporting
documentation, on the co-proposed subcategories based on either 100 lb/
yr or 400 lb/yr and whether additional characteristics of metal HAP
process vents would support alternative subcategories based on size,
class or type.
    Storage tanks. In our review for storage tanks we determined that
the NSPS for volatile organic liquid storage vessels in 40 CFR part 60,
subpart Kb applies to storage tanks at area sources. The NSPS applies
to storage tanks that are larger than 40,000 gallons and store liquid
with an MTVP greater than 0.75 pounds per square inch absolute (psia).
It also applies to storage tanks that have a capacity greater than
20,000 gallons and store liquid with a MTVP greater than 4.0 psia. We
determined that tanks meeting the applicability criteria in subpart Kb
are large storage tanks and tanks not meeting those applicability
thresholds are small tanks. Therefore, we are proposing two
subcategories for storage tanks, one for large storage tanks, which are
those that exceed the NSPS capacity and MTVP limits in subpart Kb, and
one for small storage tanks, which are those that do not exceed those
limits. We solicit comment on our subcategorization determination and
whether there are other means to differentiate among storage tanks that
would support alternative subcategories based on size, type or class.
    Cooling towers. In our review of information for cooling tower
systems we determined that certain counties in the State of Texas
require continuous monitoring of the total strippable VOC concentration
and water flow at the inlet of each cooling tower with a design
recirculation rate greater than or equal to 8,000 gal/min. This
recirculation rate is representative of typical large size cooling
towers for the chemical manufacturing industry. Smaller cooling towers
are those with a design recirculation rate less than 8,000 gal/min.
Therefore, we are proposing two subcategories for cooling tower systems
based on the size of the cooling towers and using the threshold in the
Texas requirement as the basis for differentiating among large and
small cooling towers. We solicit comment on our proposed
subcategorization and whether there are other means to differentiate
among cooling towers that would support alternative subcategories based
on size, type or class.
    Wastewater systems. In our review of information for wastewater
systems, we determined that the reported solubilities, the
concentration at which the solute no longer dissolves in water, of many
of the chemical manufacturing organic urban HAP are approximately
10,000 ppmw. Thus, wastewater streams with concentrations above this
level would separate into organic and water phases if allowed to
settle. The pharmaceuticals production MACT standard, 40 CFR part 63,
subpart GGG prohibits the discharge of multi-phase wastewater streams
to wastewater treatment systems, and this and other MACT standards
prohibit the discharge of streams that contain organic HAP at
concentrations greater than 10,000 ppmw without meeting the maximum
control standards in the rule. Because organic HAP in wastewater may
exist as a separate phase we consider this type of wastewater stream
different than an aqueous stream. We are proposing two subcategories
based on the 10,000 ppmw concentration of organic HAP, which is the
level the organic HAP generally ceases to dissolve in water. We solicit
comment on our proposed subcategorization and whether there are other
means to differentiate among wastewater systems that would support
alternative subcategories based on size, type or class.

B. How did we determine GACT?

    As provided in CAA section 112(d)(5), we are proposing standards
representing GACT for eight types of emission points at nine area
source chemical manufacturing source categories. As noted in section II
of this preamble, the statute allows EPA to establish standards for
area sources listed pursuant to section 112(c) based on GACT. The
statute does not set any condition precedent for issuing standards
under section 112(d)(5) other than that the area source category or
subcategory at issue must be one that EPA listed pursuant to section
112(c), which is the case here.
    The information used to determine the proposed GACT standards is
derived

from existing regulations that apply to some chemical manufacturing
area sources, facilities in other area source categories, and chemical
manufacturing major sources; permits and other sources of information
about control technologies and management practices that represent
current industry practice; and information regarding control
technologies used at chemical manufacturing major sources. We also
considered costs and economic impacts in determining GACT.
    We explain below in detail our proposed GACT determinations for
each of the emission points at chemical manufacturing area sources.
Table 1 of this preamble summarizes the proposed GACT standard for each
subcategory and emission point. We request comment on all of the
proposed GACT determinations.

    Table 1--Summary of Proposed GACT for Chemical Manufacturing Area
                                 Sources
------------------------------------------------------------------------
       Emission point              Subcategory          Proposed GACT
------------------------------------------------------------------------
Continuous process vents....  TRE <=1.0 and TRE     Management
                               >1.0.                 practices.
                              TRE <=1.0...........  Use control device
                                                     that reduces
                                                     organic HAP by >=95
                                                     percent.
Batch process vents.........  Organic HAP           Management
                               emissions from all    practices.
                               batch process vents
                               <19,000 lb/yr and
                               >=19,000 lb/yr.
                              Organic HAP           Use control device
                               emissions from all    that reduces
                               batch process vents   organic HAP by >=90
                               >=19,000 lb/yr.       percent.
Metal HAP process vents.....  All metal HAP         Management
                               emissions.            practices.
                              Metal HAP emissions   Use control device
                               >=100 (or 400) lb/    that reduces metal
                               yr.                   HAP emissions by
                                                     >=95 percent.
Storage tanks...............  Tank size or MTVP of  Management
                               stored material       practices.
                               less than
                               thresholds for
                               control in 40 CFR
                               part 60, subpart Kb
                               or tank size and
                               MTVP at or above
                               thresholds.
                              Both tank size and    Control in
                               MTVP of stored        accordance with 40
                               material at or        CFR part 63,
                               above thresholds in   subpart Kb.
                               40 CFR part 60,
                               subpart Kb.
Cooling tower systems.......  Cooling water         Management
                               recirculation rate    practices.
                               <8,000 gal/min.
                              Cooling water         Surrogate monitoring
                               recirculation rate    for leaks.
                               >=8,000 gal/min.
Equipment leaks.............  All.................  Quarterly
                                                     inspections for
                                                     leaks and repair of
                                                     equipment found to
                                                     be leaking.
Transfer operations.........  All.................  Submerged loading
                                                     and other
                                                     management
                                                     practices.
Wastewater systems..........  Wastewater streams    Treatment.
                               with PSHAP
                               concentrations
                               <10,000 ppmw and
                               >=10,000 ppmw.
                              Wastewater streams    Use gravity
                               with PSHAP            separation device
                               concentrations        to separate organic
                               >=10,000 ppmw.        and water layers,
                                                     and treat the water
                                                     layer.
------------------------------------------------------------------------

1. GACT for Organic HAP Process Vents
    In evaluating GACT options, we found that several facilities have
incorporated Federally enforceable provisions in their operating
permits in order to obtain synthetic minor status for HAP emissions.
Many of these facilities are reducing organic HAP emissions from
process vents by routing emissions to air pollution control devices
such as combustion devices, condensers, and carbon adsorbers. These
types of control devices are generally available technology because
they are being used by many facilities in the nine source categories at
issue to control organic HAP emissions. These controls are also used to
reduce emissions from process vents in processes at other similar area
sources. Furthermore, such controls would be required for some of these
processes if they were operated at major sources where the emission
characteristics exceed the thresholds for control in the applicable
MACT standards.
    Moreover, various federal and state regulations require organic HAP
emission reductions from process vents between approximately 90 percent
and 98 percent. For example, several states require a 90 percent
reduction from certain large process vents at pharmaceutical production
facilities. The pesticide active ingredient production NESHAP (40 CFR
part 63, subpart MMM) requires a 90 percent reduction from most process
vents. Numerous MACT rules require 98 percent reductions of organic HAP
from process vents. Some MACT standards specify an intermediate
emission limit based on reducing emissions by 95 percent. Although not
a regulation, the Alternative Control Techniques Document for Batch
Processes (see docket EPA-HQ-OAR-2008-0334) identifies 90 percent
reduction as an appropriate reduction for a range of process vent
characteristics.
    A reduction of at least 98 percent is typically achievable using
combustion devices such as thermal incinerators. A thermal incinerator
would more than meet a 90 percent reduction requirement, and for some
emission streams it is less costly than other types of control devices.
A 90 percent or 95 percent reduction, however, can also be met using
other types of control devices such as condensers. The above discussion
focuses on the types of add-on controls that are available for use on
organic process vents. In separate sections below, we discuss our
evaluation of GACT for continuous and batch process vents. That
discussion includes an evaluation of the costs associated with
different percent emission reduction requirements.
    In addition to emission limit requirements, we found that several
States require pharmaceutical facilities to enclose certain types of
equipment, except when operator access is needed for sampling,
maintenance, or inspections. We also understand that some facilities
inspect process equipment to check for leaks. We have no reason to
believe that it would be infeasible for all chemical manufacturing area
sources to operate equipment only when closed and conduct periodic
checks for leaks. Therefore we evaluated the cost of the following
management practices: (1) Cover all process tanks and mixing vessels
during operation, (2) maintain covers in the closed position on all
openings and access points in other process vessels, (3) conduct
quarterly inspections to check for leaks from the process vessels and
determine the integrity of the process vessels and ensure that covers
are being used as

specified in items 1 and 2, and (4) repair within 15 days any leaks in
the process equipment. These management practices could be implemented
by facilities with both batch process vent subcategories and both
continuous process vent subcategories. Costs to implement such
management practices are estimated to be approximately $280/yr for each
affected facility.
    Continuous process vents. As part of our GACT analysis for the two
subcategories of continuous process vents, we evaluated the costs of
using add-on control devices to achieve a 95 percent reduction of
organic HAP emissions from continuous process vents. We estimated that
two facilities in the subcategory with a TRE index value less than or
equal to 1.0 are not already achieving reduction comparable to this
emission limit. Based on a range of emission stream characteristics, a
condenser and a thermal incinerator were each determined to be the
least costly control device for one facility. The average cost-
effectiveness of control was estimated at about $3,000/ton of HAP
removed, which is consistent with cost-effectiveness for standards
based on a TRE of 1. Because this cost is reasonable, we also evaluated
the cost of a 98 percent reduction option. However, sources already
implementing controls may need to install combustion devices to achieve
98 percent emissions reduction. We could not estimate the number of
these controlled sources and baseline emissions, but the incremental
cost-effectiveness for implementing controls to meet 98 percent
relative to installing controls to meet the 95 percent reduction option
is nearly $90,000/ton.
    We also evaluated the impacts of a 95 percent reduction emission
limit for facilities in the subcategory with TRE index values greater
than 1.0. The mix of control devices used would be the same as for
facilities in the other subcategory, but the average cost-effectiveness
of this option would be about $30,000/ton of HAP removed. Because this
cost is unreasonable, we did not evaluate the cost of a more stringent
98 percent reduction option for this subcategory.
    Based on the generally available controls and management practices
and the estimated costs, we are proposing that GACT be different for
the two subcategories. For the subcategory of facilities with TRE index
values less than or equal to 1.0, we are proposing that GACT consists
of both management practices as described above and controls to meet a
95 percent reduction emission limit because the costs for both of these
options were determined to be reasonable. We have determined that
controls to meet a more stringent 98 percent reduction emission limit
do not represent GACT because the costs were determined to be
unreasonable. For the subcategory of facilities with TRE index values
greater than 1.0, we are proposing that GACT consists only of the
management practices described above because the cost of other
generally available controls to reduce emissions were determined to be
unreasonable.
    Batch process vents. As part of our GACT analysis for the two
subcategories of batch process vents, we evaluated the costs to use
add-on control devices to reduce organic HAP emissions from batch
process vents by 90 percent. We estimated that four facilities in the
subcategory with emissions equal to or greater than 19,000 lb/yr are
not already using controls that achieve this reduction. We estimated
that the flow of the emission streams at these facilities would be
relatively low and the HAP concentration relatively high so that
condensers would be the least costly control device. The cost-
effectiveness of control would be about $2,300/ton of HAP removed.
Because this cost is reasonable, we also evaluated the cost of a 98
percent reduction option. To meet the 98 percent control level, a
facility would likely need to install a combustion device. Because we
could not estimate the types of controls at sources or the number of
sources that would have to install completely new controls to meet this
standard, we estimated the incremental cost of a 98 percent control
level relative to a 90 percent control level. That incremental cost-
effectiveness is estimated at nearly $100,000/ton.
    We also examined the cost of a 90 percent reduction emission limit
for facilities in the subcategory with estimated uncontrolled emissions
from batch process vents less than 19,000 lb/yr. We estimated that this
subcategory includes 107 facilities with emission streams that span a
range of flows and concentrations. Condensers would be the least costly
control device for some facilities, and incinerators would be the least
costly control device for other facilities. The average cost-
effectiveness of control for these facilities is estimated at about
$25,000/ton of HAP removed. Because this cost is unreasonable, we did
not evaluate the cost of a more stringent 98 percent reduction option
for this subcategory.
    Based on the generally available controls and management practices
and the estimated costs, we are proposing that GACT be different for
the two subcategories. For the subcategory of facilities with batch
process vent emissions equal to or greater than 19,000 lb/yr we are
proposing that GACT consists of both management practices as described
above and a 90 percent reduction emission limit because the costs for
both of these options were determined to be reasonable. We are
proposing that a more stringent 98 percent reduction emission limit
does not represent GACT because the costs were determined to be
unreasonable. For the subcategory of facilities with batch process vent
emissions less than 19,000 lb/yr, we are proposing that GACT consists
only of management practices because the costs of other available
controls to reduce emissions were determined to be unreasonable.
2. GACT for Metal HAP Process Vents
    The metal HAP emissions tend to be PM emissions, and many processes
emit other PM along with the HAP metals compounds. As part of our GACT
analysis we determined that the same management practices described in
section IV.B.1 for organic process vents are equally feasible and
available for both subcategories of metal HAP process vents. We also
estimated that the costs are the same as for organic process vents
($280/yr per facility).
    Fabric filters and other types of control devices are widely used
to control PM emissions, including PM containing metal compounds. Such
controls are generally available, and reductions are at least 95
percent. Over 90 percent of the PM emissions from area sources are in
the form of fine particulate matter, and EPA studies have found that
fine particles continue to be a significant source of health risks in
many urban areas.
    As part of our GACT analysis, we evaluated the costs of using add-
on control devices and achieving a 95 percent metal HAP emission
reduction for the subcategory with uncontrolled metal HAP emissions of
100 lb/yr or greater and 400 lb/yr and greater. We estimated that 55
facilities are in the subcategory defined as 100 lb/yr or greater and
30 facilities are affected when the subcategory is defined as 400 lb/yr
or greater. Table 2 of this preamble summarizes the impacts of the co-
proposed requirements. The cost-effectiveness of control to the 95
percent reduction of emissions would be about $70,000/ton of HAP metal
compounds removed and $5,000/ton of PM if the subcategory is defined as
100 lb/yr or greater. The cost-effectiveness would be about $40,000/ton
of HAP metal compounds removed and $3,000/ton of PM if the subcategory
is defined as 400

lb/yr or greater. The costs for both co-proposals are considered
acceptable and are in line with the cost-effectiveness for PM in other
rules, including rules that require control of PM from other area
sources and mobile sources. We believe that these area and mobile
source rules provide a reasonable benchmark for PM cost-effectiveness.
We did not consider a control option more stringent than 95 percent
reduction because the use of add-on control devices is the most
effective control technique available.

                         Table 2--Impacts of Control Options for Metal HAP Process Vents
----------------------------------------------------------------------------------------------------------------
                                                                    Emission       Cost effectiveness (1,000 $/
                                        Total     Total annual   reduction (tpy)           ton HAP [PM])
 Uncontrolled emissions cutoff for  capital cost  cost (1,000$/-------------------------------------------------
          control, lb/yr              (1,000$)         yr)                          Relative to
                                                                  HAP       PM       baseline       Incremental
----------------------------------------------------------------------------------------------------------------
400...............................           0.7           1.7       41      570        41 [2.9]
100...............................           1.3           3.0       44      610        69 [4.9]        430 [31]
----------------------------------------------------------------------------------------------------------------

    We also evaluated the cost of using the same types of control
devices to achieve a 95 percent metal HAP emission reduction at
facilities in the subcategory with uncontrolled metal HAP emissions
less than 100 lb/yr. We estimated that 119 facilities are in this
subcategory, and the cost-effectiveness of control would be about $7
million/ton of HAP metal compounds removed and $0.5 million/ton of PM
removed. These costs are considered unacceptable.
    Based on the generally available controls and management practices
and the estimated costs, we are proposing that GACT be different for
the two subcategories. For the subcategory of facilities with
uncontrolled HAP metal emissions equal to or greater than the threshold
(100 lb/yr or 400 lb/yr), we are proposing GACT to be both management
practices as described above and a 95 percent reduction emission limit
because the costs for both of these options were judged to be
acceptable. For the subcategory of facilities with uncontrolled HAP
metal emissions less than the threshold (100 lb/yr or 400 lb/yr), we
are proposing that GACT consists only of management practices because
the cost of other generally available controls to reduce emissions were
determined to be unreasonable.
3. GACT for Storage Tanks
    Chemical manufacturing area sources that constructed,
reconstructed, or modified certain storage tanks since 1984 have been
subject to the NSPS for storage vessels in 40 CFR part 60, subpart Kb.
The NSPS requires that each storage tank that has a capacity greater
than 20,000 gallons and is used to store volatile organic liquid that
has a MTVP greater than 4.0 psia (or greater than 0.75 psia for tanks
larger than 40,000 gallons) be equipped with an internal or external
floating roof, or that the displaced vapors be routed to a control
device that reduces emissions by at least 95 percent. The number of
storage tanks at area sources that exceed the subpart Kb size and MTVP
thresholds and are not already subject to these NSPS is estimated to be
5. In this rule, we refer to these storage tanks as large tanks. The
average annual cost for complying with the above-noted requirements is
estimated at $3,000/yr, and the average cost-effectiveness is estimated
to be $2,800/ton of HAP controlled. We did not consider control levels
of 98 percent. The costs for the control required in subpart Kb are
based on floating roof control technology. With the low emissions from
storage tanks relative to process vents, the incremental cost-
effectiveness between 95 and 98 percent would be worse than for process
vents and very unreasonable when comparing the cost of floating roofs
to the cost of combustion control.
    As part of the GACT analysis, we also considered applying the
subpart Kb standards to the small tank subcategory of storage tanks
(i.e., those that do not meet the subpart Kb size and MTVP thresholds
for control). Floating roofs are not available for small or horizontal
tanks, therefore, floating roofs are not generally available for such
tanks. The cost of requiring add on controls for storage tanks is
considered unreasonable for storage tanks that do not meet the size and
MTVP thresholds. We reached the same conclusion in the rulemaking
analyses for all of the NESHAP for major sources in various chemical
manufacturing source categories. For example, the cost-effectiveness of
MON standards for small tanks (10,000 gallons) storing material with a
MTVP of 1 psia, was estimated at approximately $8,000/ton of HAP
removed. The size and MTVP thresholds vary in the NESHAP as a result of
industry-specific MACT floor determinations, but in each case the costs
to apply controls to storage tanks that do not meet the subpart Kb
thresholds were determined to be unreasonable. We have no reason to
believe that the results would be different for area sources.
    In addition to emission limits like those in subpart Kb, we also
considered generally available management practices for storage tanks.
We understand that it is common practice for facilities to periodically
inspect storage tanks to ensure that the structure is sound and liquid
is not leaking from the tank. In addition, good operating practice