[Federal Register Volume 68, Number 244 (Friday, December 19, 2003)]
[Rules and Regulations]
[Pages 70904-70946]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 03-22926]



[[Page 70903]]

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Part II





Environmental Protection Agency





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40 CFR Part 63



National Emission Standards for Hazardous Air Pollutants: Mercury 
Emissions from Mercury Cell Chlor-Alkali Plants; Final Rule

  Federal Register / Vol. 68, No. 244 / Friday, December 19, 2003 / 
Rules and Regulations  

[[Page 70904]]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 63

[OAR-2002-0017; FRL-7551-5]
RIN 2060-AE85


National Emission Standards for Hazardous Air Pollutants: Mercury 
Emissions From Mercury Cell Chlor-Alkali Plants

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: This action promulgates national emission standards for 
hazardous air pollutants (NESHAP), specifically mercury emissions, from 
mercury cell chlor-alkali plants. The final rule will limit mercury air 
emissions from these plants. The final rule will implement section 
112(d) of the Clean Air Act (CAA) which requires all categories and 
subcategories of major sources and area sources listed under section 
112(c) to meet hazardous air pollutant emission standards reflecting 
the application of the maximum achievable control technology (MACT). 
Mercury cell chlor-alkali plants are a subcategory of the chlorine 
production source category listed under the authority of section 
112(c)(1) of the CAA. The chlorine production source category was also 
identified as a source of mercury under section 112(c)(6) that must be 
subjected to standards. In addition, mercury cell chlor-alkali plants 
were listed as an area source category under section 112(c)(3) and 
(k)(3)(B) of the CAA. The final rule, which will satisfy our 
requirement to issue 112(d) regulations under each of these listings 
(for mercury), will reduce mercury emissions by about 3,068 kilograms 
per year from the levels allowed by the existing Mercury NESHAP.
    Mercury is a neurotoxicant that accumulates, primarily in the 
especially potent form of methylmercury, in aquatic food chains. The 
highest levels are reached in predator fish species. Mercury emitted to 
the air from various types of sources (usually in the elemental or 
inorganic forms) transports through the atmosphere and eventually 
deposits onto land or water bodies. When mercury is deposited to 
surface waters, natural processes (bacterial) can transform some of the 
mercury into methylmercury that accumulates in fish. Ingestion is the 
primary exposure route of interest for methylmercury. The health effect 
of greatest concern due to methylmercury is neurotoxicity, particularly 
with respect to fetuses and young children.
    In addition, in this final action, we are utilizing our authority 
under section 112(d)(4) of the CAA not to regulation chlorine and 
hydrochloric acid (HCl) emissions from the mercury cell chlor-alkali 
plant subcategory.

EFFECTIVE DATE: December 19, 2003.

ADDRESSES: Docket. We have established an official public docket for 
this action under Docket ID No. OAR-2002-0017, A-2000-32, A-2002-09, 
and OAR-2002-0016 available for public viewing at the Office of Air and 
Radiation Docket and Information Center (Air Docket) in the EPA Docket 
Center, (EPA/DC) EPA West, Room B102, 1301 Constitution Avenue, NW., 
Washington, DC.

FOR FURTHER INFORMATION CONTACT: For information concerning 
applicability and rule determinations, contact your State or local 
regulatory agency representative or the appropriate EPA Regional Office 
representative. For information concerning analyses performed in 
developing the final rule, contact Mr. Iliam Rosario, Metals Group, 
Emission Standards Division (C439-02), U.S. EPA, Research Triangle 
Park, North Carolina 27711; telephone number (919) 541-5308; fax number 
(919) 541-5600; electronic mail address: [email protected].

SUPPLEMENTARY INFORMATION: Docket. The official public docket consists 
of the documents specifically referenced in this action, any public 
comments received, and other information related to this action. 
Although a part of the official docket, the public docket does not 
include Confidential Business Information or other information whose 
disclosure is restricted by statute.
    The official public docket is the collection of materials that is 
available for public viewing. The EPA Docket Center 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 Reading Room is (202) 566-
1744, and the telephone number for the Air Docket is (202) 566-1742.
    Electronic Docket Access. You may access the final rule 
electronically through the EPA Internet under the Federal Register 
listings at http://www.epa.gov/fedrgstr/.
    An electronic version of the public docket is available through 
EPA's electronic public docket and comment system, EPA Dockets. You may 
use EPA Dockets at http://www.epa.gov/edocket/ to view public comments, 
access the index listing of the contents of the official public docket, 
and to access those documents in the public docket that are available 
electronically. Although not all docket materials may be available 
electronically, you may still access any of the publicly available 
docket materials through the docket facility in the above paragraph 
entitled ``Docket.'' Once in the system, select ``search,'' then key in 
the appropriate docket identification number.
    Judicial Review. Under CAA section 307(b), judicial review of the 
final NESHAP is available only by filing a petition for review in the 
U.S. Court of Appeals for the District of Columbia Circuit on or before 
February 17, 2004. Only those objections to the NESHAP which were 
raised with reasonable specificity during the period for public comment 
may be raised during judicial review. Under section 307(b)(2)of the 
CAA, the requirements established by today's final action may not be 
challenged separately in any civil or criminal proceeding we bring to 
enforce these requirements.
    Regulated Entities. Categories and entities potentially regulated 
by this action include:

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          Category                SIC \1\         NAICS \2\                    Regulated entities
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Industry....................            2812           325181   Alkalies and Chlorine Manufacturing.
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\1\ Standard Industrial Classification.
\2\ North American Information Classification System.

    This list is not intended to be exhaustive, but rather provides a 
guide for readers regarding entities likely to be regulated by this 
action. To determine whether your facility is regulated by this action, 
you should examine the applicability criteria in Sec.  63.8182 of the 
final rule. If you have questions regarding the applicability of this 
action to a particular entity, consult your State or local agency (or 
EPA Regional Office) described in the preceding FOR FURTHER INFORMATION 
CONTACT section.
    Worldwide Web (WWW). In addition to being available in the docket, 
an

[[Page 70905]]

electronic copy of the final rule will also be available on the WWW 
through the Technology Transfer Network (TTN). Following signature, a 
copy of the final rule will be posted on the TTN's policy and guidance 
page for newly proposed or promulgated rules http://www.epa.gov/ttn/oarpg.
    Outline. The information in this preamble is organized as follows:

I. Introduction and Background
    A. What Is the Source of Authority for Development of NESHAP?
    B. What Is the Source Category?
    C. What Criteria Are Used in the Development of NESHAP?
    D. What Actions Were Proposed for This Source Category?
    E. How Did the Public Participate in Developing the Rulemaking?
    F. What Is a Mercury Cell Chlor-alkali Plant?
    G. How Does This Action Relate to the 40 CFR Part 61 Mercury 
NESHAP?
II. Summary of Changes Since Proposal
III. Summary of the Final Rule
    A. What Is the Source Category?
    B. What Are the Affected Sources and Emission Points To Be 
Regulated?
    C. What Are the Emissions Limitations?
    D. What Are the Work Practice Standards?
    E. What Are the Operation and Maintenance Requirements?
    F. What Are the General Compliance Requirements?
    G. What Are the Initial Compliance Requirements?
    H. What Are the Continuous Compliance Requirements?
    I. How Are Initial and Continuous Compliance With the Work 
Practice Standards To Be Demonstrated?
    J. What Are the Notification and Reporting Requirements?
    K. What Are the Recordkeeping Requirements?
IV. Summary of Major Comments and Responses
    A. What Issues Were Raised Regarding the Sources That Are 
Subject to the Rule as Proposed?
    B. What Issues Were Raised Regarding the HAP Addressed by the 
Rule as Proposed?
    C. What Issues Were Raised Regarding the Compliance Date?
    D. What Issues Were Raised Regarding the Emission Limitations?
    E. What Issues Were Raised Regarding the Work Practices?
    F. What Issues Were Raised Regarding the Monitoring and 
Continuous Compliance Requirements?
V. What Are the Environmental, Cost, and Economic Impacts of the 
Final Rule?
    A. What Are the Air Emission Impacts?
    B. What Are the Non-air Health, Environmental, and Energy 
Impacts?
    C. What Are the Cost and Economic 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 of 1995
    E. Executive Order 13132--Federalism
    F. Executive Order 13175--Consultation and Coordination With 
Indian Tribal Governments
    G. Executive Order 13045--Protection of Children From 
Environmental Health Risks and Safety Risks
    H. Executive Order 13211--Actions Concerning Regulations That 
Significantly Affect Energy Supply, Distribution, or Use
    I. National Technology Transfer and Advancement Act of 1995
    J. Congressional Review Act

I. Introduction and Background

A. What Is the Source of Authority for Development of NESHAP?

    Section 112 of the CAA contains our authorities for reducing 
emissions of hazardous air pollutants (HAP). Section 112(c)(1) of the 
CAA requires us to list categories and subcategories of major sources 
and area sources of HAP and to establish NESHAP for the listed source 
categories and subcategories. Section 112(c)(6) requires us to list 
source categories and subcategories assuring that sources accounting 
for not less than 90 percent of the aggregate emissions of each of 
seven specific pollutants (including mercury) are subject to standards 
under section 112(d) of the CAA. Finally, section 112(c)(3) and 
(k)(3)(B) require that we list source categories to ensure that area 
sources representing 90 percent of the area source emissions of the 30 
urban HAP are subject to regulation under section 112(d).

B. What Is the Source Category?

    The chlorine production source category was initially listed as a 
category of major sources of HAP pursuant to section 112(c)(1) of the 
CAA on July 16, 1992 (57 FR 31576). At the time of the initial listing, 
we defined the chlorine production source category as follows:

    The Chlorine Production Source Category includes any facility 
engaged in the production of chlorine. The category includes, but is 
not limited to, facilities producing chlorine by the following 
production methods: diaphragm cell, mercury cell, membrane cell, 
hybrid fuel cell, Downs cell, potash manufacture, hydrochloric acid 
decomposition, nitrosyl chloride process, nitric acid/salt process, 
Kel-Chlor process, and sodium chloride/sulfuric acid process.

    In our subsequent analysis of the chlorine production source 
category, we did not identify any facilities that produce chlorine 
using hybrid fuel cells, the nitrosyl chloride process, the Kel-Chlor 
process, the sodium chloride/sulfuric acid process, or as a by-product 
from potash manufacturing. The majority of the source category is made 
up of chlor-alkali plants that produce chlorine and caustic (sodium 
hydroxide) using mercury cells, diaphragm cells, or membrane cells. We 
also identified operating plants that produce chlorine as a by-product: 
one from the production of sodium metal in Down cells, another from the 
production of potassium nitrate fertilizer that uses the nitric acid/
salt process, and a third that produces chlorine as a by-product from 
primary magnesium refining (magnesium refining is a separately listed 
source category and will be addressed on its own in a separate 
rulemaking). In addition, at a site where a membrane cell process is 
located, we have also identified a process that produces chlorine 
through the decomposition of HCl. Our analysis shows that the only HAP 
emitted from sources within this chlorine production source category 
are chlorine, HCl, and mercury; and mercury is only emitted from 
mercury cell chlor-alkali plants.
    In addition to the listing pursuant to section 112(c)(1), chlor-
alkali production was among the categories of sources identified 
pursuant to section 112(c)(6) to achieve the 90 percent goal for 
mercury. While this category was titled ``chlor-alkali production,'' 
the only sources of mercury emissions are mercury cell chlor-alkali 
plants. However, the mercury cell chlor-alkali subcategory was not 
officially ``listed'' under section 112(c)(6) because the chlorine 
production source category was already listed under section 112(c)(1), 
and sources of mercury emissions at mercury cell chlor-alkali plants 
would be subject to section 112(d)(2) standards via that chlorine 
production source category listing.
    Finally, on July 19, 1999 (64 FR 38706), we listed Mercury Cell 
Chlor-Alkali Plants as an area source category. In this listing, 
Mercury Cell Chlor-Alkali Plants were identified as one of the area 
source categories that contribute at least 15 percent of the total area 
source mercury emissions.
    Because of the differences in the production methods and the HAP 
emitted, we decided to divide the chlorine production category into two 
subcategories: (1) Mercury cell chlor-alkali plants, and (2) chlorine 
production plants that do not rely upon mercury cells for chlorine 
production (diaphragm cell chlor-alkali plants, membrane cell chlor-
alkali plants, etc.). Thus, on July 3, 2002, we issued separate 
proposals to address the emissions of mercury from the mercury cell 
chlor-alkali plant subcategory

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sources (67 FR 44672) and the emissions of chlorine and HCl from both 
non-mercury cell chlorine production subcategory sources and mercury 
chlor-alkali plant subcategory sources (67 FR 44713).

C. What Criteria Are Used in the Development of NESHAP?

    Section 112(d)(2) of the CAA specifies that NESHAP for new and 
existing sources must reflect the maximum degree of reduction in HAP 
emissions that is achievable, taking into consideration the cost of 
achieving the emissions reductions, any non-air quality health and 
environmental benefits, and energy requirements. This level of control 
is commonly referred to as MACT.
    Section 112(d)(3) defines the minimum level of control or floor 
allowed for NESHAP. In essence, the MACT floor ensures that the 
standards are set at a level that assures that all affected sources 
achieve the level of control at least as stringent as that already 
achieved by the better-controlled and lower-emitting sources in each 
source category or subcategory. For new sources, the MACT floor cannot 
be less stringent than the emission control that is achieved in 
practice by the best-controlled similar source. The MACT standards for 
existing sources cannot be less stringent than the average emission 
limitation achieved by the best-performing 12 percent of existing 
sources in the category or subcategory (or the best-performing five 
sources for categories or subcategories with fewer than 30 sources).
    In developing MACT, we also consider control options that are more 
stringent than the floor. We may establish standards more stringent 
than the floor based on the consideration of cost of achieving the 
emissions reductions, any non-air quality health and environmental 
impacts, and energy impacts.
    The CAA includes exceptions to the general statutory requirement to 
establish emission standards based on MACT. For pollutants for which a 
threshold has been established, section 112(d)(4) allows us ``to 
consider such threshold level, with an ample margin of safety, when 
establishing emissions standards. * * *.''

D. What Actions Were Proposed for This Source Category?

    As discussed above, we divided the chlorine production source 
category into mercury cell chlor-alkali plants, and chlorine production 
plants that do not rely upon mercury cells for chlorine production 
(non-mercury cell chlorine production). On July 3, 2002, we proposed 
one action to address mercury emissions from the mercury cell chlor-
alkali plant subcategory, and a separate action to address chlorine and 
HCl emissions from both subcategories.
    For mercury emissions from mercury cell chlor-alkali plant 
subcategory sources, we issued a proposed rule based on MACT (67 FR 
44672). Comments were received on the proposed rule and today's action 
issues the final rule for the mercury emissions from the mercury cell 
chlor-alkali plant subcategory.
    We also proposed not to regulate chlorine and HCl emissions from 
both the mercury cell chlor-alkali plant and non-mercury cell chlorine 
production subcategories under our authority in section 112(d)(4) of 
the CAA (67 FR 44713). We based this decision on our determination that 
no further control is necessary because chlorine and HCl are ``health 
threshold pollutants,'' and chlorine and HCl levels emitted from 
chlorine production processes are below their threshold values within 
an ample margin of safety. The basis for the determination was a series 
of site-specific risk assessments for every chlorine production 
facility in the United States that was located at a major source plant 
site. In addition, we concluded, using a qualitative evaluation, that 
chlorine and HCl emissions from these chlorine production facilities 
did not result in adverse environmental effects. Background for this 
action is contained in Docket OAR-2002-0016 or Docket A-2002-09. Public 
comments on the proposed action were received, and we are finalizing 
actions addressing chlorine and HCl emissions in today's Federal 
Register. In today's final action, we are utilizing our authority under 
section 112(d)(4) not to regulate chlorine and HCl emissions from the 
mercury cell chlor-alkali plant subcategory. Final action addressing 
the emissions of chlorine and HCl from the non-mercury cell chlorine 
production subcategory is contained elsewhere in today's Federal 
Register.

E. How Did the Public Participate in Developing the Rulemaking?

    Prior to proposal, we met with industry representatives and State 
regulatory authorities several times to discuss the data and 
information used to develop the proposed standards. In addition, these 
and other potential stakeholders, including equipment vendors and 
environmental groups, had opportunity to comment on the proposed 
standards.
    The proposed rule was published in the Federal Register on July 3, 
2002 (67 FR 44672). The preamble to the proposed rule discussed the 
availability of technical support documents, which described in detail 
the information gathered during the standards development process. 
Public comments were solicited at proposal.
    We received nine public comment letters on the proposed rule (two 
of which were received well after the close of the comment period). The 
commenters represent the following affiliations: Mercury cell chlor-
alkali companies, industrial trade associations, environmental/
conservation organizations, and a women's advocacy organization. In the 
post-proposal period, we talked with commenters and other stakeholders 
to clarify comments and to assist in our analysis of the comments. 
Records of these contacts are found in Docket OAR-2002-0017 or Docket 
A-2000-32. All of the comments have been carefully considered, and, 
where appropriate, the final rule has been written to so reflect.
    The proposed action not to regulate chlorine and HCl emissions was 
published in the Federal Register on July 3, 2002 (67 FR 44713). The 
preamble to the proposed action discussed the availability of technical 
support documents, which described in detail the information gathered 
during the standards development process. Public comments were 
solicited at proposal.
    We received eight public comment letters on the proposed action. 
The commenters represent the following affiliations: Industry 
representatives, governmental entities, and environmental groups. In 
the post-proposal period, we talked with commenters and other 
stakeholders to clarify comments and to assist in our analysis of the 
comments. Records of these contacts are found in Docket OAR-2002-0016 
or Docket A-2002-09. All of the comments have been carefully 
considered.

F. What Is a Mercury Cell Chlor-alkali Plant?

    Today's NESHAP apply to mercury emissions from mercury cell chlor-
alkali plants. Mercury cells are considerably larger than other types 
of chlor-alkali cells. A mercury cell plant typically has scores of 
individual cells (around 60 feet long and 9 feet wide) housed in one or 
more cell buildings. Mercury cells are electrically connected together 
in series with circuits of 30 or more cells.
    In the mercury cell process, each cell actually involves two 
distinct operations. The electrolytic cell

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produces chlorine gas, and a separate decomposer produces hydrogen gas 
and caustic solution. There is one decomposer associated with each 
cell, located directly underneath the cell. The cell and the decomposer 
are linked at the two ends by an inlet end box and an outlet end box.
    A stream of liquid mercury flows in a continuous loop between the 
electrolytic cell and the decomposer. The mercury enters the cell at 
the inlet end box and flows down a slight grade to the outlet end box. 
At the outlet end box, the mercury flows out of the cell and falls down 
to the decomposer. After being processed in the decomposer, the mercury 
is pumped back up to the inlet end box of the electrolytic cell.
    Saturated salt brine (using either sodium chloride or potassium 
chloride) is fed to the electrolytic cell at the inlet end box and 
flows toward the outlet end box on top of the mercury stream. The brine 
and mercury flow under a dimensionally stable metal anode made of a 
titanium substrate with a metal catalyst. The mercury forms the cathode 
of the cell.
    An electric current is applied between the anode and the mercury 
cathode. The electric current causes a reaction producing chlorine gas 
at the anode and a mercury:sodium (HgNa) or mercury:potassium (HgK) 
amalgam at the cathode. Chlorine is collected at the top of the cell. 
The amalgam ultimately exits at the outlet end box, falling into the 
decomposer. Depleted brine also exits the cell at the outlet end box. 
This brine is generally piped to a tank for resaturation and reuse.
    The decomposer is a packed bed reactor where the mercury amalgam is 
contacted with deionized water in the presence of a catalyst. The 
amalgam reacts with the water, regenerating elemental mercury and 
producing caustic (NaOH or KOH) and hydrogen. The caustic and mercury 
are separated in a trap at the end of the decomposer. The caustic and 
hydrogen are transferred to auxiliary processes for purification, and 
the mercury is recycled back to the cell.
    Chlorine is collected from the tops of the mercury cells by a 
common header system which runs through the cell building. Hydrogen is 
collected from the amalgam decomposers in a common header system. The 
hydrogen stream contains a small amount of mercury vapor from the 
liquid mercury processed in the decomposer. To remove the mercury 
vapor, the hydrogen stream is typically cooled, passed through a mist 
eliminator, and usually sent to a finishing device such as a carbon 
adsorber. The hydrogen may then be discharged to the atmosphere, used 
on-site, or sold for use off-site.
    In a mercury cell process, a 50 percent caustic solution is 
obtained directly from the amalgam decomposers. Thus, the mercury cell 
caustic requires little further processing to yield a commercial 
product.
    Contaminated mercury and mercury-containing wastes are generated 
from a number of sources at a mercury cell plant. These include the 
hydrogen treatment operation, the brine and caustic treatment 
operations, and mercury leaks or spills. Many plants recover mercury 
from these wastes on-site in a mercury retort, or mercury thermal 
recovery unit.
    Mercury is emitted from two point sources associated with the 
production of chlorine--the end box ventilation system and by-product 
hydrogen system. Mercury is also emitted from mercury thermal recovery 
units, which is also a point source. In addition, there are mercury 
fugitive emissions from the cell rooms and from the waste recovery 
areas.
    In addition to mercury, chlorine and HCl are emitted from mercury 
cell plants. Chlorine can be emitted from the tail gas stream from the 
final liquefier, the cell room, and equipment in chlorine service. 
Hydrochloric acid is used to pretreat feed brine prior to entering a 
chlor-alkali cell, and at other locations throughout the process to 
adjust pH. It can also be emitted from storage tanks and equipment in 
HCl service.

G. How Does This Action Relate to the 40 CFR Part 61 Mercury NESHAP?

    We promulgated the National Emission Standard for Mercury on April 
6, 1973 (40 CFR part 61, subpart E).\1\ Those standards (hereafter 
referred to as the Mercury NESHAP) limit mercury emissions from mercury 
cell chlor-alkali plants as well as mercury ore processing facilities 
and sludge incineration and drying plants. Specifically, the Mercury 
NESHAP limit mercury emissions from mercury cell chlor-alkali plants to 
2.3 kilogram (kg) (5.1 pound (lb)) of mercury per 24-hour period and 
requires that mercury emissions be measured (in a one-time test) from 
hydrogen streams, end box ventilation systems, and the cell room 
ventilation system. As an alternative to measuring ventilation 
emissions from the cell room to demonstrate compliance, the Mercury 
NESHAP allow an owner or operator to assume a cell room ventilation 
emission value of 1.3 kg (2.9 lb) per day of mercury providing the 
owner/operator adheres to a suite of approved design, maintenance and 
housekeeping practices. Every mercury cell chlor-alkali plant currently 
in operation in the United States complies with the cell room 
ventilation provisions by carrying out these practices rather than by 
measuring mercury emissions discharged from the cell room. Since every 
plant uses the 1.3 kg per day assumed value for its cell room 
ventilation emissions, subtracting the 1.3 kg per day cell room value 
from the 2.3 kg per 24-hour period plantwide standard effectively 
creates an emission limit for the combined emissions from hydrogen 
streams and end box ventilation systems of 1.0 kg per day (1,000 grams 
per day).
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    \1\ This regulatory program was originally set forth at 38 FR 
8826; April 6, 1973; and amended at 40 FR 48302, October 14, 1975; 
47 FR 24704, June 8, 1982; 49 FR 35770, September 12, 1984; 50 FR 
46294, November 7, 1985; 52 FR 8726, March 19, 1987; and 53 FR 
36972, September 23, 1988.
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    The requirements in today's final standards are more stringent than 
the requirements in the Mercury NESHAP. Using the 1,000 grams per day 
value as the baseline, we estimate that mercury emissions will be 
reduced to less than 60 grams per day (on average) by the final rule. 
This represents about 94 percent reduction from the Mercury NESHAP 
baseline for vents. In addition, the work practice standards in today's 
final rule represent the most explicit compilation of practices 
currently employed by the industry, along with detailed recordkeeping 
and reporting requirements. While we cannot quantify the mercury 
emissions reductions that would be achieved by the final work practice 
standards, we are confident that their implementation would result in 
additional reductions in mercury emissions beyond that currently 
achieved by the existing Mercury NESHAP.
    Every aspect of the Mercury NESHAP that applies to mercury cell 
chlor-alkali plants is addressed in today's final rule (40 CFR part 63, 
subpart IIIII). In fact, as discussed above, the requirements are more 
stringent than the respective requirements in the Mercury NESHAP. 
Consequently, when mercury cell chlor-alkali plants are required to 
comply with the final rule, the requirements of the Mercury NESHAP that 
apply to them will no longer be relevant or applicable. Therefore, upon 
the compliance date as indicated in Sec.  63.8186 of the final rule, 
mercury cell chlor-alkali plants will no longer have any obligation to 
comply with the Mercury NESHAP, nor will they be allowed to comply with 
the Mercury NESHAP instead of the applicable provisions in 40 CFR part 
63, subpart IIIII. Specifically, affected sources

[[Page 70908]]

subject to the final rule would no longer be subject to Sec. Sec.  
61.52(a), 61.53(b) and (c), and 61.55(b), (c) and (d) of 40 CFR part 
61, subpart E, after the compliance date, which is December 19, 2006.

II. Summary of Changes Since Proposal

    The proposed rule contained a compliance date 2 years from the date 
that the final rule would appear in the Federal Register. In the final 
rule, the compliance date has been changed to 3 years from December 19, 
2006. However, unlike the proposed rule, which would have required that 
performance tests be conducted within 180 days after the compliance 
date, the final rule requires that all performance tests be conducted 
on or before the compliance date.
    For mercury cell chlor-alkali production facilities affected 
sources, the proposed rule included a single emission limitation that 
covered all mercury emissions from the two point sources associated 
with chlorine production in mercury cells: the by-product hydrogen 
stream and the end box ventilation system vent. The format of this 
limitation was total grams of mercury per Megagram of chlorine 
production (g Hg/Mg Cl2). For the initial compliance 
determination, the aggregate mercury emissions from all hydrogen by-
product streams and all end box ventilation system vents were divided 
by the chlorine production for the same period and compared with the 
applicable emission limitation. Continuous compliance would have then 
been demonstrated by continuously monitoring the mercury concentration 
in each stream and comparing the daily average mercury concentration 
against a level determined during the initial compliance test. 
Commenters objected to this daily averaging period for compliance 
purposes when the emission limitations were based on annual average 
emissions and chlorine production. In response to these comments, we 
have written the averaging time for continuous compliance as a 52-week 
period. Further, as discussed more below, rather than establishing 
surrogate mercury concentration operating limits for each vent, 
continuous compliance is determined by a direct comparison of the 
emissions per unit of chlorine production (g Hg/Mg Cl2) for 
each 52-week compliance period and the emission limitation. This is a 
rolling average compliance period that is determined each week. That 
means a compliance determination is required each week for the previous 
52-week period.
    In addition to the averaging time for the by-product hydrogen/end 
box ventilation system vent, we changed the value of the emission 
limitation for plants with end box ventilation systems from the 
proposed limit of 0.067 g Hg/Mg Cl2 to 0.076 g Hg/Mg 
Cl2. The proposed limit of 0.033 g Hg/Mg Cl2 for 
plants without end box ventilation systems is retained in the final 
rule.
    In the final rule, we have written the method for determining 
continuous compliance for the point sources of emissions in both types 
of affected sources covered by the rule (by-product hydrogen streams 
and end box ventilation system vents at mercury cell chlor-alkali 
production facilities and mercury thermal recovery unit vents at 
mercury recovery facilities). In the proposed rule, performance tests 
would have been required to determine initial compliance with the 
applicable emission limitation. The proposed rule also would have 
required that the mercury concentration of each vent be monitored 
during these performance tests, and that a mercury concentration 
operating limit be established for each vent based on the monitoring 
results obtained during the test. Compliance with the emission 
limitation would have then been determined by comparing the results of 
the continuous monitoring of mercury concentration against the 
established operating limits. There were several comments received on 
this approach.
    In response to these comments, continuous compliance in the final 
rule is determined via a direct comparison of emissions to the emission 
limitation rather than using mercury concentration operating limits as 
a surrogate. For by-product hydrogen streams and end box ventilation 
system vents, the aggregate mercury emissions will be determined, 
divided by the corresponding chlorine production, and compared with the 
emission limitation for each 52-week compliance period (as discussed 
above). For mercury thermal recovery unit vents, the measured mercury 
concentration will be directly compared against the emission 
limitations (which are in units of milligrams of mercury per dry 
standard cubic meter, or mg/dscm). Also, the final rule contains two 
options for measuring the mercury emissions for continuous compliance: 
Continuous mercury emission monitoring systems, and periodic sampling 
using EPA reference methods or approved alternative methods.
    The proposed work practice provisions included a cell room 
monitoring program, which would have required that the mercury 
concentration be monitored in the cell room and corrective action taken 
when a plant-specific action level was exceeded. The final rule retains 
the cell room monitoring program, but it is as an alternative to the 
work practices. The optional cell room monitoring provisions in the 
final rule are more detailed and prescriptive than the requirements in 
the proposed rule, and the final rule requires the preparation and 
submittal of site-specific cell room monitoring plans. Since the cell 
room monitoring program was made optional, the final rule requires (if 
optional cell room monitoring is not chosen) the owner or operator to 
institute a floor-level mercury vapor measurement program. This program 
is designed to limit the amount of mercury vapor in the cell room 
environment through periodic measurement of mercury vapor levels.
    The final rule also requires that the owner of each mercury cell 
chlor-alkali plant report the mass of virgin mercury added to the 
cells. Initial compliance with this requirement is demonstrated by 
reporting the mass of mercury added to cells for the 5 years preceding 
the compliance date. This is a requirement requested by commenters.

III. Summary of the Final Rule

A. What Is the Source Category?

    The chlorine production source category contains the mercury cell 
chlor-alkali plant subcategory and includes all plants engaged in the 
manufacture of chlorine and caustic in mercury cells. Other non-mercury 
cell chlorine production plants used to produce chlorine and caustic, 
such as diaphragm cell and membrane cell technologies, are not covered 
by the final rule.

B. What Are the Affected Sources and Emission Points To Be Regulated?

    The final rule defines two affected sources: Mercury cell chlor-
alkali production facilities, and mercury recovery facilities. The 
former includes all cell rooms and ancillary operations used in the 
manufacture of chlorine, caustic, and by-product hydrogen at a plant 
site. The latter includes all processes and associated operations 
needed for mercury recovery from wastes.
    Emission points addressed within mercury cell chlor-alkali 
production facilities include each mercury cell by-product hydrogen 
stream, each mercury cell end box ventilation system vent, and fugitive 
emission sources throughout each cell room and various areas. Emission 
points addressed within mercury recovery facilities include each

[[Page 70909]]

mercury thermal recovery unit vent and fugitive emission sources 
associated with storage areas for mercury-containing wastes.

C. What Are the Emission Limitations?

    For new or reconstructed mercury cell chlor-alkali production 
facilities, the final rule prohibits mercury emissions.
    For existing mercury cell chlor-alkali production facilities with 
end box ventilation systems, the final rule requires that aggregate 
mercury emissions from all by-product hydrogen streams and end box 
ventilation system vents not exceed 0.076 g Hg/Mg Cl2 for 
any consecutive 52-week period. For existing mercury cell chlor-alkali 
production facilities without end box ventilation systems, the final 
rule requires that mercury emissions from all by-product hydrogen 
streams not exceed 0.033 g Hg/Mg Cl2 for any consecutive 52-
week period.
    For new, reconstructed, or existing mercury recovery facilities 
with oven type mercury thermal recovery units, the final rule requires 
that total mercury emissions not exceed 23 mg/dscm from each oven type 
unit vent. For new, reconstructed, or existing mercury recovery 
facilities with non-oven type mercury thermal recovery units, the limit 
in the final rule is 4 mg/dscm.

D. What Are the Work Practice Standards?

    The final rule contains a set of work practice standards to address 
and mitigate fugitive mercury releases at mercury cell chlor-alkali 
plants. These provisions include specific equipment standards such as 
the requirement that end boxes either be closed (that is, equipped with 
fixed covers), or that end box headspaces be routed to a ventilation 
system. Other examples include requirements that piping in liquid 
mercury service have smooth interiors, that cell room floors be free of 
cracks and spalling (i.e., fragmentation by chipping) and coated with a 
material that resists mercury absorption, and that containers used to 
store liquid mercury have tight-fitting lids. The work practice 
standards also include operational requirements. Examples of these 
include requirements to allow electrolyzers and decomposers to cool 
before opening, to keep liquid mercury in end boxes and mercury pumps 
covered by an aqueous liquid at a temperature below its boiling point 
at all times, to maintain end box access port stoppers in good sealing 
condition, and to rinse all parts removed from the decomposer for 
maintenance prior to transport to another work area.
    A cornerstone of the work practice standards is the inspection 
program for equipment problems, leaking equipment, liquid mercury 
accumulations and spills, and cracks or spalling in floors and pillars 
and beams. Specifically, the final rule requires that visual 
inspections be conducted twice each day to detect equipment problems, 
such as end box access port stoppers not securely in place, liquid 
mercury in open containers not covered by an aqueous liquid, or leaking 
vent hoses. If a problem is found during an inspection, the owner or 
operator will need to take immediate action to correct the problem. 
Monthly inspections for cracking or spalling in cell room floors are 
also required as well as semiannual inspections for cracks and spalling 
on pillars and beams. Any cracks or spalling found will need to be 
corrected within 1 month.
    Visual inspections for liquid mercury spills or accumulations are 
also required twice per day. If a liquid mercury spill or accumulation 
is identified during an inspection, the owner or operator will need to 
initiate cleanup of the liquid mercury within 1 hour of its detection. 
Acceptable cleanup methods include wet vacuum cleaning or a suitable 
alternative method approved upon petition.
    In addition to cleanup, the final rule requires that an inspection 
of equipment in the area of the spill or accumulation be conducted to 
identify the source of the liquid mercury. If the source is found, the 
owner or operator is required to repair the leaking equipment as 
discussed below. If the source is not found, the owner or operator will 
be required to reinspect the area every 6 hours until the source is 
identified or until no additional liquid mercury is found at that 
location.
    Inspections of specific equipment for liquid mercury leaks are 
required once per day. If leaking equipment is identified, the final 
rule requires that any dripping mercury be contained and covered by an 
aqueous liquid, and that a first attempt to repair leaking equipment be 
made within 1 hour of the time it is identified. The final rule 
requires that leaking equipment be repaired within 4 hours of the time 
it is identified, although there are provisions for delaying repair of 
leaking equipment for up to 48 hours.
    Inspections for hydrogen gas leaks are required twice per day. For 
a hydrogen leak at any location upstream of a hydrogen header, a first 
attempt at repair is required within 1 hour of detection of the leaking 
equipment, and the leaking equipment is required to be repaired within 
4 hours (with provisions for delay of repair if the leaking equipment 
is isolated). For a hydrogen leak downstream of the hydrogen header but 
upstream of the final control device, a first attempt at repair is 
required within 4 hours, and complete repair required within 24 hours 
(with delay provisions if the header is isolated).
    The work practice standards in the final rule require you to 
institute a floor-level mercury vapor measurement program. Under this 
program, mercury vapor levels are periodically measured and compared to 
an action level of 0.05 mg/m\3\. The final rule specifies the actions 
to be taken when the action level is exceeded. If the action level is 
exceeded during any floor-level mercury vapor measurement evaluation, 
you are required to take specific actions to identify and correct the 
problem.
    As an alternative to the full set of work practice standards 
(including the floor-level monitoring program), the final rule also 
includes an optional requirement to institute a cell room monitoring 
program whereby owners and operators continuously monitor mercury 
concentrations in the upper portion of each cell room and take 
corrective actions as soon as practicable when elevated mercury vapor 
levels are detected.
    The program is not designed to be a continuous monitoring system 
inasmuch as the results would be used only to determine relative 
changes in mercury vapor levels rather than compliance with a cell room 
emission or operating limit. The owner or operator is required to 
establish an action level for each cell room based on preliminary 
monitoring to determine normal baseline conditions. The action level, 
or levels if appropriate, will then be established as a yet-to-be-
determined multiple of the baseline values. Once the action level(s) is 
established, continuous monitoring must be conducted. If an action 
level is exceeded, actions to correct the situation are required to be 
initiated as soon as possible. If the elevated mercury vapor level is 
due to a maintenance activity, the owner or operator must ensure that 
all work practices related to that maintenance activity are followed. 
If a maintenance activity is not the cause, inspections and other 
actions will be needed to identify and correct the cause of the 
elevated mercury vapor level. Owners and operators utilizing this cell 
room monitoring program option are required to develop site-specific 
cell room monitoring plans describing their monitoring system and 
quality assurance/quality control

[[Page 70910]]

procedures that will be used, along with their action level.
    The final rule establishes the duty for owners and operators to 
routinely wash surfaces throughout the plant where liquid mercury could 
accumulate. Owners and operators are required to prepare and follow a 
written washdown plan detailing how and how often specific areas 
specified in the final rule are to be washed down to remove any 
accumulations of liquid mercury.
    Finally, the final rule requires owners or operators to record and 
report the mass of virgin mercury added to cells. Virgin mercury is 
defined as mercury that has not been processed in an onsite mercury 
thermal recovery unit or otherwise recovered from mercury-containing 
wastes onsite. In order to establish a baseline of mercury being added 
to the cells, the final rule requires owners or operators to submit the 
mass of virgin mercury added to cells for the 5 years preceding the 
compliance date.

E. What Are the Operation and Maintenance Requirements?

    The final rule requires that each owner and operator always operate 
and maintain each affected source, including air pollution control and 
monitoring equipment, in a manner consistent with good air pollution 
control practices for minimizing air emissions, as required under 40 
CFR 63.6(e)(1)(i) of the NESHAP General Provisions. The final rule 
requires each owner and operator to prepare and implement a written 
startup, shutdown, and malfunction plan according to the operation and 
maintenance requirements in Sec.  63.6(e)(3) of the NESHAP General 
Provisions.

F. What Are the General Compliance Requirements?

    The final rule requires compliance with the emission limitations 
and applicable work practice requirements at all times, except during 
periods or startup, shutdown, and malfunction as defined in 40 CFR 
63.2. The owner or operator must develop and implement a written 
startup, shutdown, and malfunction plan according to the requirements 
in 40 CFR 63.6(e)(3).

G. What Are the Initial Compliance Requirements?

    The final rule requires compliance with emission limitations and 
work practices by December 19, 2006.
    To demonstrate initial compliance with the emission limits for by-
product hydrogen streams and end box ventilation system vents, the 
final rule requires each owner or operator to conduct performance tests 
using 40 CFR part 61, appendix A, Method 102 for by-product hydrogen 
streams, and 40 CFR part 61, appendix A, Method 101 or 101A for end box 
ventilation system vents. In addition, the final rule also includes 
procedures for reducing the mercury emissions data collected during the 
performance test to units of the standard (i.e., g Hg/Mg 
Cl2). Each performance test is required to consist of a 
minimum of three 2-hour runs with a minimum sample volume of 1.7 dscm 
and must be conducted in accordance with a site-specific test plan 
prepared according to the performance test quality assurance program 
requirements in Sec.  63.7(c)(2) of the NESHAP General Provisions.
    Concurrent with each test run, each owner or operator is required 
to determine the quantity of chlorine produced using an equation 
contained in the final rule which calculates chlorine production based 
on cell line electric current load.
    Initial compliance is demonstrated by showing that the total 
mercury emission rate from all by-product hydrogen streams and all end 
box ventilation system vents for the test are less than 0.076 g Hg/Mg 
Cl2 for plants with end box ventilation systems, or 0.033 g 
Hg/Mg Cl2 for plants without end box ventilation systems.
    In addition, if the final control device is not a nonregenerable 
carbon adsorber and continuous compliance will be demonstrated using 
the periodic monitoring option, the owner or operator is required to 
monitor the following parameters during the performance test to 
establish either a maximum or minimum monitoring value, as applicable 
for the control device:

[sbull] Exit gas temperature from uncontrolled streams;
[sbull] Outlet temperature of the gas stream for the final cooling 
system when no control devices other than coolers or demisters are 
used;
[sbull] The outlet temperature of the gas stream from the final cooling 
system when the cooling system is followed by a molecular sieve or 
regenerative carbon adsorber;
[sbull] Outlet concentration of available chlorine, pH, liquid flow 
rate, and inlet gas temperature of chlorinated brine scrubbers and 
hypochlorite scrubbers;
[sbull] The liquid flow rate and exit gas temperature for water 
scrubbers;
[sbull] The inlet gas temperature of regenerative carbon adsorption 
systems; or
[sbull] The temperature during the heating phase of the regeneration 
cycle for regenerative carbon adsorbers or molecular sieves.

    As part of the initial compliance demonstration, the owner or 
operator must determine the maximum or minimum monitoring value by 
calculating the average of the data collected during the performance 
test. The exception to this is when the final control device is a 
regenerative carbon adsorber. In this case, the highest temperature 
reading during the performance test must be used.
    To demonstrate initial compliance with the mercury thermal recovery 
unit emission limits, the final rule requires that owners or operators 
conduct a performance test for each vent using 40 CFR part 61, appendix 
A, Method 101 or 101A. The owner or operator is required to develop and 
follow a site-specific test plan according to Sec.  63.7(c)(2) of the 
NESHAP General Provisions. Three test runs would need to be conducted 
at a point after the last control device for each vent.
    Initial compliance is achieved if the average vent mercury 
concentration is less than 23 mg/dscm for each oven type vent or 4 mg/
dscm for each non-oven type vent. In addition, if the final control 
device is not a nonregenerable carbon adsorber and continuous 
compliance will be demonstrated using the periodic monitoring option, 
the owner or operator is required to monitor the same parameters as 
required for by-product hydrogen streams and end box ventilation system 
vents and to establish the appropriate minimum or maximum monitoring 
value for the control device.

H. What Are the Continuous Compliance Requirements?

    The final rule contains two options for continuous compliance with 
the emission limit for by-product hydrogen streams and end box 
ventilation system vents and the emission limit for mercury thermal 
recovery unit vents: Continuous monitoring using mercury continuous 
emissions monitors, or periodic monitoring using testing. Both of these 
options will produce results in the units of the standard, so 
continuous compliance will be demonstrated through a direct comparison 
of monitoring system results.
    If mercury continuous emission monitors are used to comply with the 
final rule, a site-specific monitoring plan must be developed to ensure 
proper control device evaluation, and a performance evaluation is 
required according to the monitoring plan. For each monitor, the final 
rule requires the site-specific monitoring plan to address installation 
and siting, monitor performance specifications,

[[Page 70911]]

performance evaluation procedures and calibration criteria, ongoing 
operation and maintenance procedures, ongoing data assurance 
procedures, and ongoing recordkeeping and reporting procedures. It must 
also address how other parameters (e.g., flow rate) needed to calculate 
the mass of mercury emissions from each emission point are to be 
monitored. If periodic weekly monitoring is the selected compliance 
method, the owner or operator is required to conduct tests on a weekly 
basis using either an EPA Reference Method (101, 101A, or 102) or an 
alternative method that has been validated using Method 301, 40 CFR 
part 63, appendix A. If the final control device is not a 
nonregenerable carbon adsorber, in addition to periodic testing, the 
final rule contains requirements for the continuous monitoring of 
control device-specific parameters.
    To demonstrate continuous compliance, the final rule requires the 
owner or operator to reduce mercury emissions to 52-week averages and 
to maintain the 52-week average below 0.076 g Hg/Mg Cl2 for 
plants with end box ventilation systems, or 0.033 g Hg/Mg 
Cl2 for plants without end box ventilation systems. For 
mercury thermal recovery units, the owner or operator is required to 
determine daily average mercury emissions and maintain the daily 
average below 23 mg/dscm for each oven type vent or 4 mg/dscm for each 
non-oven type vent. The final rule requires the owner or operator to 
collect emissions data using either a continuous mercury emissions 
monitor, or by collecting weekly samples using periodic monitoring. If 
the periodic monitoring option is used and the final control device is 
not a nonregenerable carbon adsorber, the owner or operator is required 
to also monitor specific control device parameters and compare to the 
maximum or minimum monitoring values developed during the performance 
test. Continuous compliance is achieved if the monitoring values remain 
either below the maximum monitoring value, or above the minimum 
monitoring value, as appropriate.

I. How Are Initial and Continuous Compliance With the Work Practice 
Standards To Be Demonstrated?

    The final rule requires compliance with the work practice standards 
within 3 years from December 19, 2003.
    The final rule contains specific recordkeeping requirements related 
to the work practice standards. These include records of when 
inspections were conducted, problems identified, and actions taken to 
correct problems. Continuous compliance with work practice standards 
will be demonstrated by maintaining these required records.
    Initial compliance with the washdown plan will be demonstrated by 
submission of the plan by the owner or operator and certification that 
they operate according to, or will operate according to, the plan. 
Continuous compliance with the plan will be demonstrated by maintaining 
related records. Records will also be required to demonstrate 
compliance with the cell room monitoring program.

J. What Are the Notification and Reporting Requirements?

    The final rule requires that owners or operators submit Initial 
Notifications, Notifications of Intent to conduct a performance test, 
Notification of Compliance Status (NOCS), and compliance reports.
    For the Initial Notification, we are requiring that each owner or 
operator notify us that their plant is subject to the NESHAP for 
mercury cell chlor-alkali plants, and that they provide other basic 
information about the plant. For existing sources, this notification 
would need to be submitted no later than April 19, 2004.
    For the Notification of Intent report, we are requiring that each 
owner or operator notify us in writing of the intent to conduct a 
performance test at least 60 days before the performance test is 
scheduled to begin.
    The NOCS for the work practice standards will be due 30 days after 
the compliance date for existing sources. In this notification, the 
owner or operator will need to certify that the work practice standards 
are being or will be met. Furthermore, we are requiring that the 
washdown plan be submitted as part of this notification, and that the 
owner or operator certify that they operate or will operate according 
to the plan.
    For the emission limits where a performance test is required to 
demonstrate initial compliance (that is, the emission limits for by-
product hydrogen streams and end box ventilation system vents and the 
mercury thermal recovery unit vent limits), the tests will have to be 
conducted no later than the compliance date, and the NOCS will be due 
60 days after the completion of the performance test. The site-specific 
monitoring plan addressing the use of mercury continuous emission 
monitors for vents must be submitted as part of this notification.
    Compliance reporting is required semiannually, with the first 
report due within the first 6 months after initial compliance.

K. What Are the Recordkeeping Requirements?

    Records required by the final rule related to by-product hydrogen 
streams, end box ventilation system vents, and mercury thermal recovery 
unit vents include the following: Performance test results, records 
showing the establishment of the applicable mercury concentration 
operating limits (including records of the mercury concentration 
monitoring conducted during the performance tests), records of the 
continuous mercury concentration monitoring data, records of the daily 
average elemental mercury concentration values, and records associated 
with site-specific monitoring plans.
    With regard to the work practice standards, the final rule requires 
that records be maintained to document when each required inspection 
was conducted and the results of each inspection. Records noting 
equipment problems (such as end box cover stoppers not securely in 
place or mercury in an open container not covered by an aqueous liquid) 
identified during a required inspection, and the corrective action 
taken would also be required. If equipment that is leaking mercury 
liquid or hydrogen/mercury vapor is identified during a required 
inspection or at any other time, the final rule requires records of 
when the leak was identified and when it was repaired. Similarly, if a 
mercury spill or accumulation is identified at any time, the final rule 
requires records of when the spill or accumulation was found and when 
it was cleaned up.
    A copy of the current version of the washdown plan would need to be 
kept on-site and be available for inspection. Records of when washdowns 
were conducted would be required.
    The final rule requires that copies of each notification and report 
that is submitted to comply with the final rule be kept and maintained 
for 5 years, the first 2 of which must be on-site.

IV. Summary of Major Comments and Responses

    This section includes discussion of significant comments on the 
proposed rule. For a complete summary of all the comments received on 
the proposed rule and our responses to them, refer to the ``Background 
Information Document for Promulgation of National Emissions Standards 
for Hazardous Air Pollutant (NESHAP): Mercury Emissions From Mercury 
Cell Chlor-Alkali Plants'' EPA-453/R-03-012 (hereafter called the 
``response to comments document'') in Docket OAR-2002-0017 or A-2000-
32.

[[Page 70912]]

The docket also contains the actual comment letters and supporting 
documentation developed for the final rule.

A. What Issues Were Raised Regarding the Sources That Are Subject to 
the Rule as Proposed?

    There were no issues raised by commenters regarding the sources 
subject to the proposed rule and the affected source, as a mercury cell 
chlor-alkali plant is a distinct and easily identifiable entity. There 
were, however, issues raised regarding the proposed requirement for all 
affected sources to obtain a title V permit and regarding the specific 
emission points that were addressed in the proposed rule.
    Comment: Three commenters disagreed with the proposed requirements 
for all mercury cell chlor-alkali plants to obtain a title V permit, 
including area sources. The commenters requested that this provision be 
deleted from the final rule. The commenters stated that the facilities 
affected by the proposal are minor sources of HAP emissions. All three 
commenters maintained that requiring minor source facilities to obtain 
title V permits would be burdensome, e.g., due to duplicative 
recordkeeping and reporting provisions, for the area sources; one 
commenter further stated that this burden would not yield any 
environmental benefit. Additionally, according to this commenter, 
dropping the title V permit requirement for area sources would not 
lessen any substantive requirements for monitoring, recordkeeping, or 
operation of any and all air pollution control devices. Commenters 
noted that the CAA allows EPA to exempt certain sources from obtaining 
a title V permit ``* * * if the Administrator finds that compliance 
with such requirements is impracticable, infeasible, or unnecessarily 
burdensome * * *''.
    One commenter noted that in previously promulgated area source MACT 
standards (e.g., Dry Cleaning MACT and Halogenated Solvent Cleaning 
MACT), EPA identified area sources as being subject to title V 
permitting. However, EPA allowed the permitting authorities to defer 
area sources from title V permitting requirements until December 9, 
2004.
    In contrast, another commenter supported the proposed requirement 
to require all affected sources to obtain title V permits. The 
commenter argued that title V permits are needed because they 
consolidate sources' applicable requirements in a single place. The 
commenter further noted that ``* * * given the detailed work practice 
requirements, it is reasonable to expect significant source-specific 
tailoring of the standard for each plant's individual configuration.'' 
See, e.g., 67 FR 44706-07. The commenter also stated that requiring 
title V permits of area sources of mercury is especially appropriate 
because a small quantity of mercury is as toxic as far greater amounts 
of other HAP.
    Response: Section 502(a) of the CAA requires any source, including 
an area source, subject to standards or regulations under section 111 
or 112 of the CAA to operate in compliance with a title V permit after 
the effective date of any title V permits program. The Administrator 
may not exempt any major source from the requirements of title V.
    In order to exempt area sources under the final rule from title V 
requirements, the test in section 502(a) of the CAA must be met. 
Specifically, the Administrator must make a finding that title V 
requirements are impracticable, infeasible, or unnecessarily burdensome 
for the source category or categories in question. Commenters may 
provide data which would help the Administrator make such a finding, 
but the commenters who were opposed to area sources being permitted 
under the final rule did not provide any such data. Commenters 
providing supporting data for their arguments is consistent with what 
the Agency stated in its final rule for the Municipal Solid Waste 
Landfills NESHAP in reference to the test in section 502(a) of the CAA 
(68 FR 2227, 2234, January 16, 2003).
    In terms of the commenters' concern about title V adding 
duplicative recordkeeping and reporting requirements, the only 
potential duplicative requirement that we are aware of is in relation 
to deviation reporting under the semiannual compliance report required 
by Sec.  63.8254 of the final rule and the semiannual monitoring report 
required by 40 CFR 70.6(a)(3)(iii)(A) or 40 CFR 71.6(a)(3)(iii)(A). 
However, this potential duplication was addressed by Sec.  63.8254(d) 
in the proposed rule and this has been clarified in the final rule.
    As to the deferral for area sources subject to the Dry Cleaning 
MACT and the Halogenated Solvent Cleaning MACT, the area sources 
subject to these MACT standards were deferred from title V permitting 
until December 9, 2004. See final deferral rulemaking (64 FR 69637, 
December 14, 1999). This deferral was granted in part because of the 
concern that area sources would not be able to obtain the technical and 
procedural assistance from permitting authorities needed to file timely 
and complete title V applications given that permitting authorities 
would be focused on the permitting of major sources. However, as the 
title V program is no longer in its initial stages and the initial 
permitting of existing major sources is nearing completion, we would 
not be justified in granting a deferral to area sources under the final 
rule for the same reason.
    In terms of the commenter who supported the permitting of affected 
sources under the final rule, we agree that the consolidation of 
requirements in a title V permit is one of the ways that title V helps 
assure compliance with all applicable requirements. As this commenter 
also pointed out, title V permits clarify which requirements in 
standards apply to a source where requirements may vary due to various 
factors, e.g., design of the facility. Additionally, the title V 
regulations at 40 CFR part 70 and 40 CFR part 71 help a source assure 
compliance with its applicable requirements by requiring that a source 
self-certify to compliance initially and annually, by requiring that a 
source promptly report deviations from its permit requirements, and by 
requiring that a permit contain monitoring requirements. It is also 
important to note that the title V permitting process provides an 
opportunity for the public to comment on whether a source is complying 
with its applicable requirements. In short, title V permits can enhance 
the effectiveness of rules such as the final rule, and EPA, therefore, 
disagrees that there are no environmental benefits to requiring title V 
permits for area sources.
    In conclusion, as the test in section 502(a) of the CAA has not 
been met, EPA has retained the requirement in the final rule that 
affected sources subject to the final rule must obtain title V permits. 
Therefore, whether an affected source under the final rule is a part of 
a major or area source, the major/area source is required to obtain a 
title V permit.
    Comment: One commenter believed that the proposed rule violated the 
CAA because the Agency did not establish standards for some parts of 
chlor-alkali plants that emit mercury. The commenter noted that under 
the proposed rule, EPA defined two affected sources: Mercury cell 
chlor-alkali production facilities and mercury recovery facilities. The 
commenter did not agree with EPA's determination that within mercury 
cell chlor-alkali production facilities, chlorine purification, brine 
preparation and wastewater treatment operations should not be subject 
to emission standards

[[Page 70913]]

because they have low mercury air emissions. Similarly, the commenter 
did not agree with EPA's decision not to regulate chemical mercury 
recovery and recovery in batch purification stills at mercury recovery 
facilities. According to the commenter, the CAA does not allow the 
Agency to exempt certain classes, types and sizes of sources from 
emission standards, unless EPA finds no potential for emissions. 
Therefore, the commenter stated that EPA had a legal obligation to 
establish standards that cover all mercury-emitting parts of chlor-
alkali facilities, and the Agency must re-visit and set emission 
standards for the parts of the production and recovery facilities with 
low mercury emissions.
    Response: During development of the proposed rule, we did not 
receive any data to indicate that mercury was emitted from chlorine 
purification, brine preparation, or wastewater treatment operations, 
and our knowledge of the process indicated that any potential emissions 
would be very limited (67 FR 44674). Furthermore, we did not receive 
any data indicating that control measures designed to reduce HAP were 
in use at existing facilities that had these units. The same holds true 
for chemical mercury recovery and recovery in batch purification stills 
at mercury recovery facilities. Therefore, with no reported emissions 
and process evidence that any emissions would be very limited, we 
concluded that there was no potential for emissions. Adding to this the 
existence of a MACT floor of no control (because none are controlled), 
we did not regulate these processes.
    The commenter did not provide emissions data that would indicate 
that these sources emit significant amounts of mercury, or emit mercury 
at all. Therefore, the final rule does not contain standards for 
mercury emissions from chlorine purification, brine preparation, 
wastewater treatment operations, chemical mercury recovery and recovery 
in batch purification stills.
    We point out that the final rule does contain very stringent 
emission limitations for all point sources that have been demonstrated 
to be sources of mercury emissions. Further, the work practice 
requirements in the final rule address fugitive mercury emissions in 
all areas of the facility, including the chlorine purification, brine 
preparation, wastewater treatment areas, as well as areas where 
chemical mercury recovery processes and batch purification stills are 
located.

B. What Issues Were Raised Regarding the HAP Addressed by the Rule as 
Proposed?

    As noted earlier, we divided the chlorine production category into 
two subcategories: Mercury cell chlor-alkali plants and chlorine 
production plants that do not rely upon mercury cells for chlorine 
production (diaphragm cell chlor-alkali plants, membrane cell chlor-
alkali plants, etc.). On July 3, 2002, we issued separate proposals to 
address the emissions of mercury from the mercury cell chlor-alkali 
plant subcategory sources (67 FR 44672) and the emissions of chlorine 
and HCl from both the non-mercury cell chlorine production subcategory 
sources and the mercury cell chlor-alkali subcategory sources (67 FR 
44713). Specifically, we proposed a rule for mercury emissions from 
mercury cell chlor-alkali plants, and we proposed not to regulate 
chlorine and HCl emissions from mercury cell chlor-alkali plants and 
non-mercury cell chlorine production plants under our authority in 
section 112(d)(4) of the CAA.
    Comments were received regarding the proposed action not to 
regulate chlorine and HCl emissions (see Air Docket OAR-2002-0016 or 
Air Docket A-2002-09). The aspects of these comments related to the 
mercury cell chlor-alkali plant subcategory can be generally classified 
into two basic categories: Our statutory authority under section 
112(d)(4); and the site-specific risk assessments that formed the basis 
for our decision.

Comments Related to the Section 112(d)(4) Authority

    Comment: Several comments were received related to our decision not 
to regulate chlorine and HCl emissions from chlorine production under 
the authority of section 112(d)(4). Some commenters supported this 
decision and stated the interpretation of our authority under section 
112(d)(4) was appropriate and supported by the legislative history. In 
contrast, other commenters disagreed with EPA's interpretation of 
section 112(d)(4). Finally, some of the commenters stated that EPA 
should use its authority under section 112(c)(9)(B)(ii).
    One commenter stated that EPA conducted an appropriate analysis to 
determine that human exposures from ambient concentrations are well 
below threshold values with an ample margin of safety. According to 
another commenter, any further regulation of chlorine and HCl emissions 
from the chlorine production industry would have no environmental 
benefits, but would result in costs for monitoring, recordkeeping, and 
reporting efforts to certify compliance with any requirements. The 
commenter was concerned that a regulation would also stretch EPA's 
limited resources in monitoring for compliance. Three commenters stated 
that EPA's interpretation of their authority under section 112(d)(4) 
was supported by the legislative history, which emphasizes that 
Congress included section 112(d)(4) in the CAA to prevent unnecessary 
regulation of source categories. The commenter agreed that under 
section 112(d)(4), once EPA establishes that a pollutant has a health 
threshold and that exposure to that pollutant's emissions are below the 
health threshold, EPA should refrain from setting MACT standards for 
that pollutant. The commenter further suggested that EPA should use 
section 112(d)(4) whenever setting emission standards under section 
112(d).
    Three commenters disagreed with EPA's interpretation of section 
112(d)(4). They did not believe that section 112(d)(4) could be used as 
an alternative to setting MACT standards under section 112(d)(3). One 
commenter noted that the phrase ``in lieu of'' was not included in the 
section 112(d)(4) provisions and that its absence was intentional. In 
support of their claim, the commenter pointed to section 112(d)(5), 
which does contain the phrase ``in lieu of.'' The commenter interpreted 
section 112(d)(4) to mean that health-based thresholds can be 
considered when establishing the degree of MACT requirements, but not 
in place of the requirement to establish a MACT floor pursuant to 
section 112(d)(3).
    The commenter also pointed to the provisions of section 112(c)(2) 
which require the Administrator to establish NESHAP for listed source 
categories and subcategories. The commenter was concerned that EPA 
evaluated emissions from chlorine production plants and concluded that 
since they do not pose a threat to human health and the environment, 
the Administrator is relieved of her responsibilities to establish a 
MACT standard. The commenter maintained that this position is not 
supported by section 112(c)(2).
    The commenter also referred to section 112(d)(1), stating that EPA 
did not have the authority to ``make a determination of no regulation 
for a listed source category or pollutant.''
    Finally, the commenter referred to section 112(d)(3), which 
contains the MACT floor provisions. According to the commenter, the 
intent of the NESHAP program is to develop a MACT

[[Page 70914]]

floor, and EPA is not fulfilling the requirements of the CAA by not 
performing such an analysis. The commenter stated that a majority of 
facilities identified in the analysis have adequate controls due to 
State regulations and these controls should be incorporated into the 
MACT floor evaluation. The commenter was particularly concerned that by 
not developing a MACT floor, no new-source MACT standards were created. 
The commenter requested that EPA perform a MACT floor analysis and 
develop a NESHAP for new sources.
    Two of the commenters stated that EPA should support its decision 
not to regulate the chlorine production source category by citing the 
provisions of section 112(c)(9)(B)(ii) in addition to the provisions of 
section 112(d)(4). The commenters stated that the evaluation performed 
by EPA would also be sufficient for deleting sources under section 
112(c)(9)(B)(ii) and that EPA's proposal to not regulate chlorine 
production is similar to deleting a subcategory of the Chlorine 
Production source category. Therefore, in addition to using the 
authority under section 112(d)(4), the commenters suggested that EPA 
delete the subcategory using the authority under section 
112(c)(9)(B)(ii) to avoid any uncertainty over the use of its authority 
under section 112(d)(4).
    Response: The EPA has the authority under CAA section 112(d)(4) to 
decide not to establish a NESHAP for chlorine and HCl emissions from 
certain chlorine production facilities. We have decided to limit our 
use of section 112(d)(4) to the emissions of chlorine and HCl from 
sources within the mercury cell chlor-alkali subcategory. While we have 
decided to establish no standards for the emissions of these two HAP 
from sources in the mercury cell chlor-alkali plant subcategory, we are 
establishing standards for the mercury emissions from the sources 
within that subcategory. As explained elsewhere in today's Federal 
Register, we have decided to delete the non-mercury cell chlorine 
production plants subcategory under CAA section 112(c)(9)(B)(ii). The 
only HAP emitted by the non-mercury cell chlorine production sources 
are chlorine and HCl.
    Contrary to other commenters claims that our use of section 
112(d)(4) is inappropriate, both the statutory language and the 
legislative history of the provision support our decision not to set 
limitations for chlorine and HCl emissions from sources in the mercury 
cell chlor-alkali plant subcategory. The language of section 112(d)(4) 
provides the Agency with ample discretion to utilize a risk-based 
approach in determining whether to establish emission standards for 
those HAP where we determine that the HAP are ``threshold pollutants'' 
and that the standard (or no standard) will achieve an ``ample margin 
of safety.''
    The statutory language in section 112(d)(4) is ambiguous. Thus, 
under the Supreme Court's decision in Chevron v. NRDC, 467 U.S. 837 
(1984), the Agency has the discretion to interpret the language to 
allow us to establish NESHAP that do set limitations on certain HAP 
emitted from sources (``when establishing standards'') but to also 
decide not to set limitations on other HAP emitted from these same 
sources if the other HAP are threshold pollutants and the risk from the 
emissions are so low that no standard for that second set of HAP is 
necessary to protect the public and the environment with ``an ample 
margin of safety.''
    This approach is consistent with prior decisions EPA has made in 
the context of two other NESHAP. First, in the NESHAP for combustion 
sources at pulp mills (40 CFR part 63, subpart MM), we chose not to set 
a standard for HCl emissions from recovery furnaces, while we did set 
standards for other HAP emitted from the same sources within the 
category. We explained this decision in the preamble to the proposed 
MACT standard and received no adverse comment on the approach (63 FR 
18754, 18765-68, April 15, 1998). Second, we proposed to set no 
standard under section 112(d)(4) for HCl emitted from lime kilns, while 
we also proposed to set standards for other HAP emitted by these same 
sources (67 FR 78046 December 20, 2002). We also received no adverse 
comment on that proposed decision. While we originally proposed to 
utilize section 112(d)(4) to set no standard for chlorine and HCl from 
chlorine production sources in a separate notice of the Federal 
Register (67 FR 44713, July 3, 2002), we made it clear that the 
proposed use of section 112(d)(4) would apply to emissions of these two 
HAP from mercury cell chlor-alkali sources (as well as the emissions of 
chlorine and HCl from other chlorine production sources).
    We do not agree that Congress' use of the phrase ``in lieu of'' in 
CAA section 112(d)(5) so clearly restricts any possible interpretation 
of CAA section 112(d)(4) such that some form of a MACT standard must 
always be set even when the criteria of section 112(d)(4) are met. 
Instead, we interpret that Congress enacted section 112(d)(4) to 
provide EPA with the discretion to take risk into account and decide 
that standards need not be set when the HAP are threshold pollutants 
and levels being emitted are below the threshold value with an ample 
margin of safety. Moreover, in each case where we have exercised 
authority under section 112(d)(4), we have established standards in 
each category (or subcategory, as here) for those pollutants that do 
not satisfy the threshold pollutant and ample margin of safety 
statutory criteria.
    We also disagree with the commenter who argued that the provision 
in section 112(c)(2), which requires the Administrator to establish 
emission standards for listed categories and subcategories, has much 
bearing on our use of section 112(d)(4) in this circumstance. By 
setting a standard for the emission of mercury from the mercury cell 
chlor-alkali plant subcategory, we are fulfilling our obligations under 
section 112(c)(2). As stated earlier, we have utilized the same 
approach in our other uses of section 112(d)(4), e.g., HCl emissions 
from combustion sources at pulp mills and lime production sources.
    The statutory language in section 112(d)(1) and (3) does not 
prevent us from deciding that no emission standard is necessary for a 
particular threshold pollutant which is being emitted at levels well 
below the ample margin of safety when we are also establishing 
standards for HAP emitted from sources in that same category or 
subcategory. This approach to our use of section 112(d)(4) is 
consistent with the statutory language of section 112(d)(1) and (3). We 
are establishing emission standards for the listed category or 
subcategory, but are deciding that no MACT floor need be established 
and no emission standard set for those HAP that meet the criteria of 
``threshold pollutant'' and ``ample margin of safety.''
    With regard to the concerns the commenter raised about the failure 
to set a standard for new sources, our review of the mercury cell 
subcategory indicates that no new mercury cell chlor-alkali plants will 
be constructed. Given that our emission standard for new sources in the 
mercury cell chlor-alkali subcategory prohibits the emission of 
mercury, we do not believe any new sources using mercury cells for 
chlorine production will ever be constructed (or reconstructed). 
Therefore, this no-mercury emissions requirement in the final rule 
will, in effect, also ensure that there are no chlorine or HCl 
emissions from new mercury cell facilities.
    In response to other commenters' suggestion that we utilize the 
authority of section 112(c)(9)(B)(ii) to delete the chlorine production 
category, we have

[[Page 70915]]

decided to exercise our authority under that statutory provision for 
the non-mercury cell chlorine production subcategory. That decision is 
discussed in a separate notice in today's Federal Register. However, we 
are not deleting the mercury cell chlor-alkali plant subcategory 
because the sources within the category also emit mercury, and we are 
establishing emissions standards for mercury emissions in today's final 
rule.
    Comment: Some commenters concluded that we did not establish either 
cancer or noncancer thresholds for HCl and chlorine and, therefore, it 
is illegal for EPA to attempt to use section 112(d)(4) to set 
standards.
    Response: The ``threshold level'' in section 112(d)(4) refers to 
the level of concentration of a chemical under which no health effects 
are expected from exposure, although this term is not defined in 
section 112. Further, section 112 does not address the process that 
must be followed to ``establish'' a threshold level.
    The reference concentration (RfC) is a ``long-term'' threshold, 
defined as an estimate of a daily inhalation exposure that, over a 
lifetime, would not likely result in the occurrence of noncancer health 
effects in humans. We have determined that the RfC for HCl of 20 
micrograms per cubic meter ([mu]g/m3) is an appropriate 
threshold value for assessing risk to humans associated with exposure 
to HCl through inhalation http://www.epa.gov/iris/subst/0396.htm.
    In cases where we have not studied a chemical itself, we rely on 
the studies of other governmental agencies, such as the Agency for 
Toxic Substances and Disease Registry (ATSDR) or the Office of Health 
Hazard Assessment of California's Environmental Protection Agency (CAL 
EPA), for RfC values. The CAL EPA developed an RfC value of 0.2 [mu]g/
m3 for chlorine based on a large inhalation study with rats.
    Acute exposure guideline level (AEGL) toxicity values are estimates 
of adverse health effects due to a single exposure lasting 8 hours or 
less. The confidence in the AEGL (a qualitative rating of either low, 
medium, or high) is based on the number of studies available and the 
quality of the data. Consensus toxicity values for effects of acute 
exposures have been developed by several different organizations, and 
we are beginning to develop such values. A national advisory committee 
organized by EPA has developed AEGL's for priority chemicals for 30-
minute, 1-hour, 4-hour, and 8-hour airborne exposures. They have also 
determined the levels of these chemicals at each exposure duration that 
will protect against discomfort (AEGL1), serious effects (AEGL2), and 
life-threatening effects or death (AEGL3). Hydrogen chloride has been 
assigned AEGL values (65 FR 39264, June 23, 2000), including the 1-
hour, AEGL1 of 2,700 [mu]g/m3 used in our revised analysis. 
Chlorine has also been assigned AEGL values (62 FR 58840), including 
the 1-hour AEGL1 of 1,500 [mu]g/m3 used in our revised 
analysis.
    We maintain that the listing of health thresholds by EPA and other 
organizations in the public domain as discussed above has 
``established'' health thresholds for HCl and chlorine. Further, the 
recognition of these levels by EPA, ASTDR, and CAL EPA indicates that 
chlorine and HCl are threshold pollutants.
    Moreover, we provided the public an opportunity to comment on the 
thresholds for chlorine and HCl that we used in our original analysis 
for the proposed action (67 FR 44716). We used the same threshold level 
for HCl for both the proposed and final NESHAP for the pulp and paper 
mill category. We have also used the same threshold for HCl in the 
proposed and final NESHAP for lime production (67 FR 78046; final 
action is anticipated in August 2003). There is no requirement in 
section 112(d)(4) that EPA develop or finalize a threshold for a 
particular HAP in a certain manner. The thresholds we have used for 
both HCl and chlorine are consistent with the statutory language in 
section 112(d)(4).

Comments Related to the Risk Assessment

    Comment: In the analysis for the proposed action (67 FR 44713), we 
used the HCl RfC to determine the long-term health effects of chlorine 
emissions, since chlorine photolyzes very quickly to HCl in sunlight. 
Two comments supported this methodology and stated that our decision 
was based on sound scientific knowledge of the pollutants of concern.
    In contrast, two other commenters did not agree with our use of the 
HCl RfC as a threshold level for chlorine. The commenters stated that 
not all of the annual chlorine emissions can be considered as HCl and, 
therefore, the chlorine exposure was underestimated. The commenters 
argued that chlorine emissions will not undergo photolysis to convert 
to HCl when there is not bright sunshine (i.e., at night or on cloudy 
days).
    Response: The widely accepted fact that chlorine is photolyzed in 
sunlight formed the basis for the assumption in the original risk 
assessment that chronic exposure to chlorine would not occur. As a 
result of this comment, we re-examined the literature on the 
atmospheric fate of chlorine to validate our original assumption.
    The additional information obtained from the literature confirmed 
our earlier information. There are several different pathways that 
molecular chlorine can take, including photolysis (reaction with 
light), reactions with hydroxyl radicals, reactions with oxygen atoms, 
and reactions with water vapor. Each pathway results in different 
amounts of Cl2 being removed from the troposphere, and 
different pathways are predominant at different times of the day. 
However, photolysis is the primary pathway.
    Therefore, this information did not fundamentally change the 
assumption made in the original risk assessment, which was that on a 
long-term basis, individuals will be exposed more to HCl formed from 
the photolysis of chlorine than to chlorine. However, the commenters 
are correct that there will be situations where individuals will be 
exposed to chlorine. Therefore, in addition to the assessment where we 
considered only acute exposure to chlorine, we concluded that it was 
appropriate to consider the effects of chronic exposure to chlorine 
emissions from chlor-alkali plants. In order to provide an upper bound 
estimate of the chronic risks to compare with the lower bound estimates 
assuming that all chlorine was converted to HCl, we conducted modeling 
assuming that no chlorine is photolyzed.
    In general, we consider an exposure concentration which is below 
the RfC concentration (what we call a hazard quotient of less than 1) 
to be ``safe.'' This is based on the definition of RfC. The RfC is a 
peer reviewed value defined as an estimate (with uncertainty spanning 
perhaps an order of magnitude) of a daily inhalation exposure to the 
human population (including sensitive subgroups) that is likely to be 
without appreciable risk of deleterious noncancer effects during a 
lifetime (i.e., 70 years).
    As discussed above, we conducted additional modeling for major 
source facilities within the subcategory using the same model used for 
the proposed action (ISCST3) to estimate chronic chlorine exposure 
using the assumption that no chlorine is photolyzed to HCl. The hazard 
quotients resulting from this additional modeling defined the upper 
bound of our risk assessment. The highest upper-bound hazard quotient 
estimated by the model is just over 0.3. (For more details regarding 
this revised risk assessment, refer to table 2 of the responses to 
comment document, available in the docket.) Given the health protective 
assumptions used in

[[Page 70916]]

this analysis, the value of 0.3 represents a hypothetical exposure that 
is well above what we would expect actual exposures to be. This is 
because chlorine is converted to HCl in the presence of sunlight within 
a few minutes. In addition, the hazard quotient of 0.3, which results 
from this exposure scenario is well below the safe value of 1. Thus, we 
have concluded that, even assuming that some chronic exposure to 
chlorine may occur, that none of the major sources included in this 
subcategory will have emissions of chlorine or HCl that exceed a level 
of exposure which is adequate to protect public health and the 
environment with an ample margin of safety.
    Comment: Two commenters did not support EPA's use of the AEGL2 for 
use as a short-term exposure limit for chlorine and HCl. One commenter 
stated that the AEGL2 values would not sufficiently protect public 
health because they would allow emissions at levels that cause 
``discomfort,'' and according to the commenter, discomfort is an 
adverse health effect. The commenter also complained that EPA did not 
explain why it chose to use AEGL2 rather than AEGL1 or AEGL3. The 
commenter explained that although emissions from chlorine plants did 
not exceed AEGL2 values, the emissions may exceed AEGL1 values, and if 
they did, the proposed action would not meet the statutory 
requirements. Another commenter stated that AEGL limits are not 
appropriate for assessing daily human exposure scenarios because they 
were developed for emergency planning. The commenter recommended that 
EPA use the American Conference of Governmental Industrial Hygienists 
(ACGIH), which has a 1-hour Short Term Exposure Limit (STEL) similar to 
the AEGL1 value of 1 part per million (ppm) for chlorine and is used to 
protect against eye and mucous membrane irritation. The commenter 
stressed that EPA must use conservative benchmarks before concluding 
that an ample margin of safety exists.
    Response: The AEGL values represent short-term threshold or ceiling 
exposure values intended for the protection of the general public, 
including susceptible or sensitive individuals, but not 
hypersusceptible or hypersensitive individuals. The AEGL values 
represent biological reference values for this defined human population 
and consist of three biological endpoints for each of four different 
exposure periods of 30 minutes, l hour, 4 hours, and 8 hrs.
    As utilized in the proposed action, the AEGL2 1-hour concentrations 
for chlorine and HCl are 5,800 [mu]g/m3 and 33,000 [mu]g/
m3, respectively.
    The 1-hour AEGL1 concentration for chlorine is 2,900 [mu]g/
m3 and the corresponding value for HCl is 2,700 [mu]g/
m3. The ACGIH short term exposure limit (STEL) for chlorine, 
which is 1 ppm is approximately equal to the AEGL1 value of 2,900 
[mu]g/m3.
    Although we stand by our original analysis, which used the AEGL2 
level, we have incorporated the commentor's suggested use of the AEGL1 
values (possibly with a safety factor) for determining whether an ample 
margin of safety has been obtained. Therefore, we simply compared the 
short term (1-hour average) modeling results from the original acute 
risk assessment to the AEGL1 values. These results were obtained by 
modeling the maximum allowable hourly emissions reported in the section 
114 responses for each of the sources. For plants that did not report 
fugitive emissions, fugitive emissions were estimated using worst-case 
emission factors.
    The maximum modeled 1-hour chlorine concentration for two of the 
three plants with the mercury cell chlor-alkali process is less than 5 
percent of the AEGL1 (and ACGIH) value for chlorine. Further, the 
highest modeled concentration for any plant, 155 [mu]g/m\3\, is less 
than 6 percent of the AEGL1 values. The highest modeled 1-hour HCl 
concentration for any plant, 32 [mu]g/m\3\, is less than 2 percent of 
the AEGL1 value for HCl. Furthermore, all of the mercury cell chlor-
alkali facilities also produce chlorine using a non-mercury chlorine 
production process (i.e., diaphragm cells). The modeled emissions 
represent chlorine and HCl emissions from both processes. Therefore, 
the chlorine and HCl emissions from the mercury cell chlor-alkali 
process would be even lower.
    Based on this comparison, we conclude that the chlorine and HCl 
emissions from mercury cell chlor-alkali production plants do not 
represent an unsafe level of acute exposure. We further maintain that, 
along with the chlorine exposure assessment, this proves that an ample 
margin of safety is provided with no additional control.
    Comment: Two commenters supported EPA's method of selecting a risk 
assessment approach to meet the unique needs of the chlorine production 
industry. The commenters agreed that the risk assessment methodology 
should not be interpreted as a standardized approach that would set a 
precedent for how EPA will apply CAA section 112(d)(4) in future cases. 
Furthermore, the commenters stated that the degree of conservatism 
built into all aspects of the risk assessment conducted for the 
chlorine production source category could vary greatly in future risk 
assessments for other source categories. The commenters stressed that 
the conservative assumptions made in the health effects assessment, 
emissions estimates, and exposure assessment were appropriate for the 
proposed action.
    In contrast, one commenter stated that the risk assessment fell 
short of the Agency's prior practice. According to the commenter, 
whenever EPA has made determinations to regulate a specific pollutant 
based on health considerations (e.g., national ambient air quality 
standards (NAAQS) for ozone and PM), the Agency evaluated health 
effects and exposure in great detail. The commenter contended that in 
this case, EPA appears to be content with ``the bare and unsupported 
assumptions about what health levels are safe.'' The commenter argued 
that it was not appropriate for EPA to use a rigorous approach when 
setting standards and a more cursory approach when making a decision 
not to regulate.
    Response: We disagree with the one commenter's characterization of 
the assessment that forms the basis for this decision, and we strongly 
dispute the characterization of the assessment as ``bare and 
unsupported.'' As discussed elsewhere in this preamble, we maintain 
that the RfC and AEGL values used as benchmarks for this assessment are 
scientifically sound and appropriate. The emissions data and other 
inputs used for this analysis, which were provided by the industry and 
checked by our staff, are representative of the industry.
    In this assessment, the predicted health effects estimated, using 
very conservative inputs and assumptions, were well below the 
recognized health thresholds. While our approach in this particular 
action may not be the same as an approach for a NAAQS, we believe that 
it has been certainly more than ``cursory.'' We have looked at 
emissions and exposure data for each of the major sources in the 
subcategory. We have established hazard indices for chlorine and HCl 
for each major source in the subcategory. We performed a qualitative 
ecological assessment. Moreover, in response to comment received, we 
have revised our analyses and taken into account comments that we have 
received when performing these reassessments. We will base each risk 
assessment for this and future regulatory action on sound scientific 
principles.
    Comment: In the proposed action, the risk assessment modeling was 
conducted by placing receptors at the

[[Page 70917]]

geographic center of census blocks within 2 kilometers of the site and 
in the population-weighted centers of census block groups or census 
tracks out to 50 kilometers. Two commenters did not agree with this 
methodology for determining receptor location for threshold pollutants. 
One commenter stated that EPA's methodology would be more appropriate 
for cancer causing agent, where the risk is based on probabilities of 
health effects. The commenter argued that for noncancer (i.e., 
threshold pollutants) compounds, placing the receptors at the center of 
census tracks would not properly identify the highest impacts close to 
the facility. They felt that it was more appropriate to measure the 
exposure of the most exposed individual (e.g., someone living at the 
fence line of a facility or directly downwind).
    Response: We certainly agree with the commenters that the greatest 
impacts will likely occur near the facility for this source 
subcategory. However, we do not agree with the commenters that our 
approach fails to meet statutory requirements. We do not feel that 
considering an ``ample margin of safety'' means that we must 
demonstrate no risk or adverse health effects for a theoretical person 
living at the fence line. Rather, it is appropriate to assess the risks 
at locations where people most likely reside. A census block is the 
smallest geographic unit for which the Census Bureau tabulates 100 
percent data. While census blocks in rural areas may be larger, many 
blocks correspond to individual city blocks in more populated areas. 
The commenter is correct in that an individual could live closer to the 
plant than the center of the census block and our approach would have 
slightly underestimated risk. It is just as likely, however, that the 
closest individual could live farther from the plant than the center of 
the census block causing our risk estimates to be slightly 
overestimated. By placing receptors at the center of populated census 
blocks on all sides of a facility, we have evaluated people living 
``downwind.'' In conclusion, we continue to feel that placing a 
receptor in the geographic center of populated census blocks near a 
facility is a well established approach to exposure modeling which 
results in a reasonable approximation of estimating the risks where 
people actually live, and we maintain that this methodology is 
appropriate for actions taken under the authority of section 112(d)(4).
    Comment: One commenter stated that all chlorine emissions from 
chlorine production facilities that are collocated with other source 
categories need to be reviewed as a whole when evaluating public health 
risk, adverse environmental effects, and possible control strategies. 
The commenter stressed that other sources of chlorine and HCl should be 
included in the risk assessment under section 112(d)(4). The commenter 
was concerned that not accounting for all chlorine and HCl emissions 
from a facility would provide the community with a false sense of 
assurance of protection and is not consistent with the legislative 
intent of the CAA to consider cumulative HAP exposure issues through an 
integrated approach under section 112(d), 112(f), and 112(k). 
Therefore, the commenter requested that EPA evaluate the potential for 
adverse health and environmental impacts using conservative risk 
assessment methodology that incorporates all known chlorine and HCl 
emissions from a contiguous facility.
    Response: Section 112 of the CAA requires us to list categories and 
subcategories of major sources and area sources of HAP and to establish 
NESHAP for the listed source categories and subcategories. In directing 
us how to establish MACT emission limits, section 112(d)(3) of the CAA 
requires us to set the emission limitation at a level that assures that 
all major sources achieve the level of control at least as stringent as 
that already achieved by the better-controlled and lower-emitting 
sources in each source category or subcategory. Therefore, the entire 
MACT program is structured on a source category-specific basis. All 
MACT standards developed to date have addressed emissions from specific 
source categories.
    There are instances where mercury cell chlor-alkali facilities are 
collocated with other source categories. However, based on the risk 
assessment for chlorine and HCl emissions from mercury cell chlor-
alkali plants, the predicted impacts from chlorine and HCl at these 
plants are extremely low. We believe that the human health and 
environmental impacts from all sources in the subcategory even when 
collocated with other chlorine and HCl emissions will still be within 
an ample margin of safety to protect the public health, and will not 
cause adverse environmental effects. Moreover, as indicated in the 
preamble to the proposed action, most major processes at the sites 
where mercury cell chlor-alkali facilities are located are subject to, 
or will be subject to, NESHAP to reduce HAP emissions (67 FR 44714, 
July 3, 2002). Therefore, it would be inappropriate to include 
emissions from those sources in an assessment for the mercury cell 
chlor-alkali subcategory conducted under the authority of section 
112(d)(4).
    Comment: Two commenters stated that the environmental effects 
analysis was not adequate. One commenter stated that potential 
ecological effects of HCl emissions have not been properly referenced. 
One commenter stated that EPA's proposed action falls short of its 
obligation to protect against environmental effects. According to the 
commenter, EPA has understated its statutory obligation in the proposed 
action. The commenter referred to the legislative history, which 
indicates that CAA section 112(d)(4) requires standards that ``would 
not result in adverse environmental effects which would otherwise be 
reduced or eliminated.'' The commenter listed the several shortcomings 
in the EPA's environmental assessment.
    The commenter concluded that although EPA acknowledged that it had 
an obligation to ensure that any standards set under section 112(d)(4) 
did not have any adverse environmental effects, the Agency did not 
properly consider the issue. Therefore, the commenter stated that EPA 
could not promulgate standards under section 112(d)(4) without 
contravening the CAA.
    Response: While CAA section 112(d)(4) makes no mention of 
environmental effects, we took the potential of such adverse effects 
into account when we issued our proposed action. The level of our 
analysis at proposal was adequate to satisfy the requirements of 
section 112(d)(4). The commenters did not suggest that they believed 
there was the potential for adverse environmental effects from HCl or 
chlorine emissions from mercury cell chlor-alkali plants. Were there 
any evidence that such adverse effects were likely, or even possible, 
we would have conducted a more intensive ecological risk assessment.
    The commenters are correct, however, that we did not discuss the 
ecological effects of chlorine. This was because, as was stated in the 
proposal preamble, we did not perform a separate evaluation of chronic 
chlorine exposure because chlorine is converted to HCl in the 
atmosphere so rapidly.
    Atmospheric exposure is the primary pathway for environmental 
effects from chlorine emissions. However, since most chlorine is 
converted to HCl, studies have focused on the effects of HCl on 
vegetation. Although plant exposures to elevated levels of chlorine can 
cause plant injury, it tends to be converted to other, less toxic forms 
rather rapidly in plants and may not result in the direct accumulation 
of

[[Page 70918]]

toxic pollutant residuals important in the food chain.
    Plant studies have found foliar damage due to chlorine emissions, 
decreased levels of chlorphyll a and b, decreased leaf areas, obvious 
chlorosis, and a decline in fruit production due to chlorine emissions.
    There is evidence of effects to animals due to accidental and/or 
catastophic exposures, but the chlorine concentrations of these 
exposures are unknown. However, there are no data on exposure to 
historic or atmospheric concentrations.
    More information is available on the effects of chlorine from 
aquatic exposures. However, there is no evidence that suggests that 
emissions of chlorine from industrial sources in the air contribute 
significantly to aquatic concentrations of chlorine.
    One study reported a significant decrease in phytoplankton activity 
following exposure to 0.1 ppm chlorine in cooling tower water. 
Additional laboratory studies showed that continuous exposure to 0.002 
milligrams per liter (mg/L) total residual chlorine (TRC) resulted in 
depressed algal biomass in naturally-derived microcosms.
    When exposed continuously for 96 hours to 0.05 mg/L TRC, the 
Eurasian water milfoil showed a significant reduction in shoot and dry 
weights, shoot length, and chlorophyll content.
    Aquatic invertebrates are very sensitive to chlorine and reaction 
products of chlorine, with early life stages showing the most 
sensitivity. For example, free chlorine, monochloramine, and 
dichloroamine have been shown to reduce the rate of oyster larvae 
survival. Many studies have been performed, and the results are highly 
variable depending on the chlorine species, the lifestage of the 
invertebrate, and other factors such as salinity. The most sensitive 
aquatic species appears to be molluscan larvae, with lethal 
concentration 50% (LC50) of 0.005 mg/L. Sublethal effects 
have also been studied, including reduced growth, reduced motility, and 
reproductive failure.
    The effects on fish also vary depending on the life stage and fish 
species and environmental factors, such as the pH, temperature, and 
type of chlorine species. Larval stages are more susceptible to 
effects, and freshwater species are more sensitive than marine species. 
Free chlorine is generally more toxic than residual chlorine; where the 
form of chlorine is dependent on the pH of the water. Sublethal effects 
such as avoidance, reduction of diversity in chlorinated effluents, 
reduction or elimination of spawning, abnormal larvae, reduced oxygen 
consumption, and gill damage have been noted. Many LC50 
values were reported, ranging from 0.08 mg/L after 24 hours of exposure 
to TRC to 2.4 mg/L after 0.5 hours of exposure to TRC.
    Acute and chronic exposures to predicted chlorine and HCl 
concentrations around the sources are not expected to result in adverse 
toxicity effects. These pollutants are not persistent in the 
environment. The chlorine and HCl emitted should not significantly 
contribute to aquatic chlorine concentrations and are not likely to 
accumulate in the soil. Chlorine rapidly converts to HCl in the 
atmosphere, and chlorine and HCl are not believed to result in 
biomagnification or bioaccumulation in the environment. Therefore, we 
do not feel there will be adverse ecological effects due to chlorine 
and HCl emissions from mercury cell chlor-alkali plants.

C. What Issues Were Raised Regarding the Compliance Date?

    Comment: Commenters requested an extension of the compliance date, 
which was proposed to be 2 years from the effective date of the final 
rule. The commenters recommended that the compliance date should be 
changed to 3 years after promulgation. The commenters stated that 
affected facilities are being required to install costly, complex 
control and monitoring equipment, as well as establish additional 
operating and maintenance procedures at their facilities in order to 
ensure compliance with the emission limitations and work practice 
requirements of the proposed rule. The commenters believed that 2 years 
was not a sufficient period of time to complete such tasks, 
specifically the continuous monitoring requirements.
    Response: We agree that since the existing sources are required to 
install complex monitoring equipment and to establish additional 
operating and maintenance procedures, it is reasonable to allow more 
time than the proposed 2-year compliance period. Section 63.6(c)(1) of 
the NESHAP General Provisions states that ``* * * in no case will the 
compliance date * * * exceed 3 years after the effective date of * * 
*.'' Therefore, the final rule specifies that the compliance date for 
existing sources is 3 years after the effective date of the final rule.

D. What Issues Were Raised Regarding the Emission Limitations?

    Comment: One commenter, which submitted comments after the close of 
the comment period, recommended that EPA re-define MACT to ban the use 
of mercury cell technology. The commenter explained that this would be 
easily achievable because the majority of the chlorine production 
industry already uses other, superior technologies such as membrane 
cells and diaphragm cells. The commenter claimed that EPA abused its 
authority to establish subcategories of emission sources by creating a 
subcategory of ``mercury cell chlor-alkali plants'' within the chlorine 
production source category which limits the pool of facilities upon 
which the MACT floor is based to those who create dangerous pollution, 
as opposed to those industry leaders that use non-polluting and readily 
available equipment.
    The commenter further listed a lack of confidence that the mercury 
cell process could be adequately controlled. The commenter explained 
that the work practice requirements which are proposed to address 
fugitive emissions, the largest source of emissions from this process, 
are too weak.
    Finally, the commenter stated that converting all mercury cell 
plants to membrane cells would still be cost-effective, and that their 
estimate of the cost to convert all mercury cell plants to other 
technologies ($920 million) was justifiable given the significant 
threat to public health and the environment posed by mercury.
    Response: We disagree with the commenter that we abused our 
authority to create subcategories by subcategorizing the chlorine 
production industry and only including mercury cell plants in the MACT 
floor analysis. It is our general policy to subcategorize when there 
are technical distinctions among classes, types, or sizes of sources, 
and manufacturing processes of sources, that would impact setting an 
appropriate emission limit even when creating the subcategories leads 
to some with a small number of sources. This policy is supported by the 
broad discretion provided to the Agency to establish subcategories 
under CAA section 112(c), the legislative history, and EPA's prior 
rulemakings.
    In general, EPA has previously taken the position that 
subcategorization is appropriate where types of emissions and/or types 
of operation make use of the same air pollution control technology 
infeasible. The EPA's rulemakings reflect this general understanding 
and provide criteria for subcategorization that focus on the 
appropriateness of applying similar technology-based requirements at 
different sources.

[[Page 70919]]

    The EPA feels that the subcategorization scheme it has used for 
this category of sources (as described above and in the proposed rule) 
is consistent with the statute, the legislative history, and EPA's past 
implementation of section 112(c) and the MACT program. The HAP emitted 
by the two subcategories (mercury cell chlor-alkali plants and non-
mercury cell chlorine production) plants are different--while plants in 
both categories emit chlorine and HCl, only plants in the mercury cell 
subcategory emit mercury. The processes used to produce chlorine that 
the plants in the two subcategories used are generally different 
(because of the use of the mercury cells). Thus, no change was made in 
response to this comment and the final rule does not ban mercury cells 
(except the final rule does prohibit the emission of mercury from new 
or reconstructed chlor-alkali production facility sources).
    With regard to the cost effectiveness of a ban of mercury cell 
chlor-alkali facilities, the commenter did not provide any basis for 
their estimate so we could not verify these costs. Further, we do not 
feel that ``conversion'' accurately describes the replacement of a 
mercury cell plant to another technology. There is little salvageable 
from a mercury cell plant that can be used in the construction of a 
membrane cell plant, so the demolition of the mercury cell plant 
followed by the construction of a membrane cell plant is a more 
accurate characterization.
    Therefore, we did not promulgate a final rule that requires non-
mercury technology for chlorine production.
    Comment: Two commenters did not agree with the proposed ``beyond-
the-floor'' emission limitations. They stated that there is no 
justification for EPA to set emission limits beyond the floor, as 
proposed. The commenters stressed that EPA is required to assess the 
cost-benefit relationship when considering ``beyond the MACT floor'' 
limitations. According to the commenters, the Agency did not set forth 
an accurate basis for costs associated with meeting the MACT floor or 
cost/benefits associated with meeting the ``beyond the MACT floor'' 
emission limitations.
    These commenters were also concerned that the very low emission 
limits required by EPA's beyond-the-floor determination cannot be 
obtained by the industry as a whole. Specifically, the commenters 
stated that the Agency lacks high quality point source emission data 
upon which to base their ``beyond-the-floor'' limits. The commenters 
pointed out that the mercury emission limitations for hydrogen vent gas 
streams are based on limited data provided by a single facility in 
Maine that has been closed for nearly 2 years. The commenters 
maintained that for all of the eleven plants combined (ten affected 
plants plus the closed Maine plant), there was very little high quality 
point source emission data. Due to the significant chance that the data 
used to develop the standard are biased and quantitatively non-
representative, the commenters stated that the Agency was not justified 
in moving beyond the floor to the most stringent value ever obtained by 
the industry.
    The commenters further argued that EPA's conclusion that the 
``beyond-the-floor'' emission limitations can be met with existing, 
commercially available control equipment is not supported and thereby 
seriously flawed. The commenters pointed out that EPA presented no data 
in the preamble or elsewhere in support of their decision that the 
proposed standards could be met with commercially available control 
systems.
    Response: First, we disagree with the commenters' assertions that 
we did not have justification for going beyond the floor, and that we 
did not have an accurate basis for costs associated with meeting the 
MACT floor or meeting beyond-the-floor emission limitations. We 
conducted a very detailed plant-specific cost impacts analysis which is 
available in the docket. The commenters did not provide any specific 
comments on this detailed analysis or any specific data or rationale to 
refute our cost analysis. Therefore, we stand by our original analysis 
and have not made any changes to the cost impacts approach. Based on 
our analysis, we concluded that the costs/benefits of going beyond the 
floor are warranted. Given the persistent nature of mercury in the 
environment and its associated health and welfare impacts, we continue 
to feel that the additional emission reductions that will be achieved 
by the beyond-the-floor option are warranted considering the associated 
costs.
    However, in the proposal preamble (67 FR 44682), we acknowledged 
that there was uncertainty associated with the level of control 
associated with the beyond-the-floor option proposed because the 
molecular sieve adsorption control technology is no longer commercially 
available, and because the plant representing this level of control is 
no longer operating. We did not receive any comments indicating that 
the molecular sieve control technology is commercially available. 
Further, since the plant has closed, we were unable to obtain 
additional information to further scrutinize the data to ensure that 
they were not biased and quantitatively non-representative. Therefore, 
we have concluded that we cannot fully demonstrate that the proposed 
beyond-the-floor standard is achievable using commercially available 
technology.
    In the proposal preamble, however, we also stated that we were 
retaining the option of setting the standard at the next lowest 
normalized emission value of 0.076g Hg/Mg Cl2 for plants 
with end box ventilation systems. The plant with this emissions level 
controls its by-product hydrogen system with a series of iodine and 
potassium iodide impregnated carbon adsorbers, and their end box 
ventilation system vent with a condenser and demister, which are 
commercially available technologies. Further, in the documentation for 
the proposed standard, we determined on a plant-specific basis which 
commercially available technologies could be made to comply with the 
proposed standard. The commenters provided no comment on why the 
application of the very specific application of these technologies 
could not achieve the emission limitations.
    The emissions estimates for the facility with normalized emissions 
of 0.076 g Hg/Mg Cl2 are based on weekly testing using 
methods that are modifications of EPA Methods 101A and 102. The primary 
difference between the methods used by the facility and the EPA 
Reference Methods is that the sampling is not isokinetic. We discussed 
our opinion that data obtained using this type of modified method were 
acceptable to use in MACT standards in the proposal BID. Therefore, it 
can be considered that the emission estimates used to establish the 
level of 0.076 grams Hg/Mg Cl2 are based on weekly 
performance tests. We do not consider such data to be of low quality. 
Therefore for the final rule, we have selected the 0.076 grams Hg/Mg 
Cl2 beyond-the-floor option as MACT for plants with end box 
ventilation systems.
    For the by-product hydrogen stream for plants without end box 
ventilation systems and mercury thermal recovery unit vents, there were 
no questions raised regarding the availability of the control 
techniques used at the lowest emitting plants that formed the basis for 
the proposed emission limitations. Further, at proposal, we examined 
the data used to establish the emission limitations and determined that 
they were of adequate quality to be used to establish standards. 
Therefore, the final rule retains the proposed emission limitations for 
these emission sources.
    Comment: Commenters were concerned that the proposed mercury

[[Page 70920]]

emission limitation for by-product hydrogen had a daily averaging 
period for continuous compliance. According to the commenters, the 
Agency developed the proposed standard using annual average emissions 
and actual annual production and then interpolated to a daily limit 
without regard to statistical error. Therefore, the commenters 
requested either an annual average emission rate limit or that the 
daily limit be set at not less than two times the annual limit divided 
by 365 (days).
    Response: The commenters are correct in that the normalized mercury 
emissions used to establish the standards were based on annual average 
emissions and annual actual chlorine production. Therefore, the 
commenters' concerns about the variability of the control systems over 
a year and the ability to comply on a daily basis with this limit have 
merit. We considered the two options offered by the commenters (a 365-
day compliance period and adjustments to account for daily variations).
    We do not feel that it would be appropriate to apply a generic 
multiplier to the limit for mercury cell chlor-alkali plants to account 
for short-term variation. In addition, mercury cell emissions data were 
not available to assess the variability in emissions from these 
emission points. Therefore, we concluded that the emission limitation 
should reflect an annual average. This would be consistent with the 
data used to create the emission limitation and would allow for short-
term variations in operations and control device performance.
    The final rule is allowing weekly monitoring/testing as an 
alternative method to determine continuous compliance with the emission 
limitations. In order to be consistent with the continuous compliance 
approach, we concluded that the by-product hydrogen/end box ventilation 
emission limitation in the final rule should be annualized on a 52-week 
rolling basis. Specifically, the final rule requires that mercury 
emissions from all by-product hydrogen streams and end box ventilation 
system vents not exceed 0.076 grams Hg/Mg Cl2 for any 
consecutive 52-week period.

E. What Issues Were Raised Regarding the Work Practices?

    Comment: One commenter recommended that EPA establish numerical 
standards for fugitive emissions. The commenter maintained that, absent 
published information on good mass balance analyses performed at chlor-
alkali facilities, one can only assume that significant mercury losses 
are occurring through fugitive emissions. Accordingly, the commenter 
felt it is crucial that the EPA step up efforts to address all 
potential release routes from such facilities, including fugitive 
emissions.
    Another commenter, which submitted comments after the close of the 
comment period, expressed the view that the mercury consumed cannot be 
accounted for in material balances. This commenter asserted that the 
proposed rule failed to address the majority of the true annual mercury 
emissions from the mercury cell chlor-alkali industry. The commenter 
explained that the mercury used in this industry is not incorporated 
into final products or consumed in the process, so all mercury 
purchased is used to replenish mercury that has been lost from the 
manufacturing process. The commenter compared the amount of mercury 
purchased by the industry in 1994 (136 tons) to EPA's estimate of 
annual emissions (22,200 pounds or 11.1 tons) and concluded that the 
proposed rule fails to account for nearly 90 percent of the true 
mercury emissions from this industry. The commenter drew this 
conclusion based on the assumption that most of the mercury would be 
released to the air rather than transferred off-site as solid waste or 
accumulated in on-site tanks and ponds. The commenter noted that EPA's 
estimate of annual emissions was based on outdated and inadequate 
estimates of fugitive emissions which were based on short-term 
measurements taken when fugitive emissions were non-representatively 
low.
    One of these commenters, who submitted comments after the comment 
period, recommended that EPA require both monitoring of fugitive 
emissions from cell rooms and waste storage areas and establish a 
reduction goal for such emissions. According to the commenter, 
technologies are available to quantify airborne mercury concentrations 
continuously, and in combination with estimates of air flow rates, 
estimates of fugitive loss rates under selected conditions could be 
made and could serve as the basis for reduction targets.
    Response: The issue of unaccounted for mercury has been the subject 
of intense scrutiny from other groups within EPA and the indusry. As 
part of the Great Lakes Binational Toxics Strategy, mercury cell 
chlorine producers annually report the total mercury consumption for 
the industry. From the baseline consumption of 160 tons per year (tpy) 
for the years 1990-1995, the industry reported an 81 percent reduction 
of mercury consumed in 2001 (30 tpy). One of the commenters 
characterized the 2001 consumption as an outlier, but the 79 tpy 
consumed in 2000 still represents a significant decrease from the 
baseline level.
    Even with this decrease in consumption, significant mercury remains 
unaccounted for by the industry. The mercury releases reported to the 
air, water, and solid wastes in the 2000 Toxics Release Inventory (TRI) 
totaled around 14 tons. This leaves around 65 tons of consumed mercury 
that is not accounted for in the year 2000.
    While it may appear to the commenters that the discrepancy in the 
mercury material balance is the result of fugitive emissions, there is 
little empirical evidence to support this conclusion. The commenters 
did not provide any emissions data to support their assertion. 
Furthermore, industry personnel claim that mercury which condenses and 
accumulates in pipes, tanks, and other plant equipment makes up a large 
component of the unaccounted for mercury. While the commenters 
completely discount this claim by the industry, it is relevant to 
consider the very high density of mercury. For instance, the 65 tons of 
unaccounted for mercury in 2000 averages just over 7 tons per plant. 
One gallon of mercury weighs around 113 pounds, meaning that around 124 
gallons of mercury would be unaccounted for per plant. This is a very 
small percentage (less than 2 percent) of the amount of mercury 
typically on site at most facilities. However, the industry is also 
unable to fully substantiate their theory. Therefore, the fate of all 
the mercury consumed at mercury cell chlor-alkali plants remains 
somewhat of an enigma.
    We agree that work practice standards should only be set when it is 
not feasible to prescribe or enforce an emission standard. Indeed, our 
reasons for establishing work practices instead of numerical limits are 
based on factors associated with the practicality and feasibility of 
setting a realistic limit against which compliance can be measured and 
enforced.
    First, data are not available to establish a numerical emission 
standard for fugitive emissions. As stated in the proposal preamble (67 
FR 44680), emissions data for fugitives from cell rooms and waste 
storage areas are very limited. Second, we do not agree with the 
commenter's implication that available measurement technologies could 
support enforcing a numerical emission standard for the following 
reasons:

[sbull] Mercury emission monitors have not been used to monitor 
fugitive

[[Page 70921]]

emissions at mercury chlor-alkali facilities for compliance 
demonstrations;
[sbull] The variability in the number of and location of exhaust vents 
at each facility affects the amount of air moved through the cell rooms 
and thus affects the mass emission rate of the fugitives; and
[sbull] The variability of the cell room roof configuration affects the 
feasibility of using the continuous emissions monitors at each 
facility.

    Therefore, the establishment of numerical emission limitations for 
fugitive emissions from the cell room and other areas is ``not 
feasible,'' as defined in CAA section 112(h)(2)(B). Thus, the final 
rule retains the work practice elements of the proposed rule.
    However, in response to the concerns about unaccounted for mercury, 
we did add a provision in the final rule that requires each facility to 
record and report the mercury consumed each year. While there are no 
mercury consumption reduction targets in the final rule, we believe 
that reporting mercury consumption on a plant-specific basis will 
encourage additional action to identify unaccounted for mercury and 
reduce mercury consumption.
    Comment: A commenter that submitted comments well after the close 
of the comment period expressed the opinion that there was a 
fundamental flaw in the proposed rule because the proposal will weaken 
existing sources' obligations to limit mercury emissions from the cell 
room. They cited 42 U.S.C. Sec.  7412(d)(7), which prohibits emission 
standards from weakening existing standards. This commenter summarized 
the 40 CFR part 61 mercury NESHAP, which requires mercury cell chlor-
alkali plants to not emit more than 2,300 grams per day of mercury from 
the entire facility, including the cell room, the by-product hydrogen 
streams, the end box ventilation system vents, and other sources of 
mercury. The commenter stated that even if emissions from all other 
points were zero, emission from the cell room cannot exceed 2,300 grams 
per day. The commenter acknowledged that an owner or operator may 
forego cell room emission testing and assume that cell room emissions 
are 1,300 grams/day, but pointed out that complying with these work 
practices does not absolve the owner or operator of the obligation to 
meet the applicable numeric emission standard.
    The commenter contrasted this with the proposed rule, which 
established numerical emission standards for by-product hydrogen 
streams, end box ventilation systems, and mercury thermal recovery unit 
vents, but not for cell room fugitive emissions. The commenter claimed 
that emissions from the cell room will be able to exceed 2,300 grams/
day so long as the work practices are followed, when the rule as 
proposed prohibits such a result.
    The commenter concluded that it is not sufficient to say that the 
work practices that have been proposed are more stringent than the 
existing requirements, because neither the existing nor proposed work 
practices by themselves require any given numeric level to be achieved. 
They argued that the existing numeric limit provides EPA and the public 
with an enforceable limit of performance to which owners and operators 
can be held. The commenter went on to indicate that such a numerical 
standard is particularly necessary, as plants are currently emitting 
far more than 2,300 grams per day of mercury. To support this 
assertion, the commenter provided information indicating that mercury 
cell plants add much more mercury to their cells than 2,300 grams per 
day, and they concluded that cell room emissions is a very likely way 
that mercury is lost. In conclusion, the commenter stated that it would 
be inappropriate for EPA to rely entirely on a work practice standard 
and eliminate stricter provisions that would enable the Agency to 
insist that facilities keep their emissions below a set level.
    Response: The 40 CFR part 61, Mercury NESHAP, Sec.  61.53(c)(1), 
contains requirements for stack sampling to determine emission levels 
for cell room ventilation systems at mercury chlor-alkali plants. If an 
owner or operator meets the prescribed work practice standards, they 
can assume a mercury emission rate from the cell room of 1,300 grams 
per day.
    While the final rule does not retain the numerical emission 
limitation from the 40 CFR part 61 Mercury NESHAP, the requirements in 
the final rule for fugitive mercury emissions from the cell room are 
far more stringent than the design, maintenance, and housekeeping 
practices allowed by the Mercury NESHAP in lieu of meeting the 
numerical limit. In addition, the Mercury NESHAP contained only 18 work 
practice requirements as compared to the more than 80 design, 
operation, maintenance, inspection, and required actions for repair 
contained in tables 1 through 4 to the final rule. The work practice 
standards specify the equipment and areas to be inspected along with 
the frequency of the inspections and conditions that trigger corrective 
action. Response time intervals for when the corrective actions must 
occur are also specified. Furthermore, some types of inspections are 
required at more frequent intervals than required by the Mercury NESHAP 
(e.g., inspecting decomposers for hydrogen leaks twice per day rather 
than once each day). In addition, the detailed recordkeeping procedures 
and reporting provisions are more fully developed than those in the 
Mercury NESHAP, as well as requirements for storage of mercury-
containing wastes.
    Finally, the work practice standards contain a requirement for 
owners and operators to develop and implement a plan for the routine 
washdown of accessible surfaces in the cell room and other areas. The 
standards establish the duty for owners or operators to prepare and 
implement a written plan for washdowns and specify elements to be 
addressed in the plan. A requirement for washdowns is an important part 
of an overall approach to reducing cell room fugitive emissions.
    Along with a floor-level periodic mercury monitoring program 
(discussed later), not only will the work practice standards in the 
final rule result in reduced mercury fugitive emissions (and, 
therefore, mercury consumption), but provide much more enforceable 
provisions so that an inspector can verify that they are being met.
    In addition, we have calculated emission reductions for the final 
rule. Assuming that every facility is complying with the 1,000 grams 
per day limit from point sources (this value assumes that 1,300 grams 
per day of the 2,300 grams per day facility limit are being used for 
fugitive emissions), we estimate that baseline emissions from all nine 
existing facilities (relative to the Mercury NESHAP) are 3,285 kg/yr. 
We estimate that annual emissions after the application of MACT to be 
217 kg/yr. Therefore, the final rule will result in emission reductions 
of 3,068 kg/yr, or approximately 93 percent from the existing Mercury 
NESHAP. This supports our position that we are not setting a standard 
that allows backsliding. Therefore, once the final rule compliance date 
ensues, sources subject to the provisions of the final rule will no 
longer be subject to the Mercury NESHAP.
    Comment: Commenters disagreed with EPA's proposal to institute a 
continuous mercury monitoring program whereby owners and operators 
would be required to continuously monitor mercury concentration in the 
upper portion of each cell room and take corrective actions when 
elevated mercury vapor levels are detected. The commenters stated that 
the proposed

[[Page 70922]]

monitoring program was seriously flawed and should be deleted from the 
final rule. The commenters noted that periodic monitoring done in 
various areas of the cell room (as currently practiced to ensure 
compliance with Occupational Health & Safety Administration (OSHA) 
permissible exposure limits) was an appropriate substitute. Several 
commenters stated that they would not be opposed to the continuous 
mercury monitoring program if the technology were field demonstrated.
    In contrast, one commenter, which submitted comments after the 
close of the comment period, ``enthusiastically'' supported the 
proposed cell room monitoring program. Nonetheless, the commenter felt 
that it was unwise for the EPA to allow each owner/operator to set his/
her own cell room action level.
    Some commenters stated that cell room monitoring is redundant to 
the housekeeping requirements, and that the work practices required in 
Tables 1-5 to the proposed rule allow for sufficient opportunity to 
quickly detect abnormal sources of mercury emissions. Another commenter 
stated that the final rule should either require continuous monitoring 
or detailed work practice standards but not both. The commenter argued 
that cell room designs vary greatly. Given this variability, the 
commenter urged EPA to enable facilities to select the appropriate 
compliance strategy for individual circumstances.
    Response: With regard to technical feasibility, a cell room mercury 
monitoring system was tested in 2000 at a mercury cell facility in 
Augusta, Georgia, that demonstrated that the monitoring technology can 
be effectively installed and operated in mercury cell chlor-alkali 
plant cell rooms, and this technology, along with other measures, can 
be an effective mechanism to identify leaking equipment and other 
problems that result in fugitive mercury emissions from the cell room.
    We acknowledge that this success, which occurred in a limited and 
very controlled situation for a short time period, does not necessarily 
prove that similar monitoring at every mercury cell room would prove to 
be an effective long-term method to reduce mercury fugitive emissions. 
In fact, the design and operation of the Augusta facility probably 
represented the optimum circumstances for a mercury cell room 
monitoring program to be successful. We are aware that cell room 
designs vary greatly and recognize that the design affects the location 
and number of monitors necessary to accurately monitor each individual 
cell room. In addition, depending on the design of the roof, it may be 
possible that installation of monitors that adequately monitor mercury 
concentration would not even be possible.
    Even with these limitations, a well designed and implemented cell 
room monitoring program can effectively reduce mercury fugitive 
emissions on a long-term basis. Therefore, we included this concept in 
the final rule.
    However, we do agree with the commenters that a comprehensive 
continuous cell room monitoring program should be sufficient to reduce 
fugitive mercury emissions from the cell room without imposing the 
overlapping requirements of the detailed work practices. Therefore, we 
have concluded that it is appropriate to allow facilities to implement 
the continuous cell room monitoring program as an alternative to, and 
not in addition to, the work practice requirements. In the final rule, 
facilities are given the option to implement the cell room continuous 
monitoring program in lieu of the work practice requirements. We do, 
however, feel there is a need to outline more specifically the elements 
that must be included in the cell room monitoring program to ensure 
that it provides at least the same level of control as the work 
practices and cell room monitoring program would have provided 
together. Therefore, there are more prescriptive requirements in the 
final rule for the cell room monitoring plan option. The final rule 
dictates how the action level is to be established, what measures must 
be followed when the action level is exceeded, and what records must be 
kept.
    Although the continuous cell room monitoring provisions are 
optional, some mercury monitoring to detect elevated mercury levels in 
the cell room is appropriate. Therefore, we have included a periodic 
monitoring program to be performed throughout the cell room as a 
substitute for continuous monitoring. The final rule contains a floor-
level periodic monitoring program as part of the work practice 
standards.

F. What Issues Were Raised Regarding the Monitoring and Continuous 
Compliance Requirements?

    Comment: Three commenters questioned EPA's intent in establishing 
emission limitations based on the initial performance test. These 
commenters felt that the proposed standards amounted to changing the 
emission limit based on the emissions observed during the performance 
test which amounted to ignoring the emission limit established through 
the rulemaking process. Two of the commenters stated that the amount of 
mercury emissions measured during the initial compliance performance 
test should be used only to verify compliance with the MACT standards, 
and not to establish new emission limits. The commenters were concerned 
that the emission limits would become floating limits based on the most 
recent performance test, as opposed to being MACT standards.
    The commenters indicated that variations around the concentrations, 
above and below, measured during the performance test can be expected. 
Treatment systems employed to obtain compliance (e.g., carbon) would be 
expected to show some slight deterioration after a period of operation. 
Therefore, a performance test conducted just after a carbon change 
would result in an unrealistically low operating limit. Finally, the 
commenters were concerned that different facilities would have 
different operating limits, depending on variables like the type of 
control equipment installed, the operating conditions on the day of the 
emission test (i.e., mercury volatility changes significantly with 
temperature), and other factors. One commenter was concerned that, 
given the wide variability in emission constituents, operators would 
not be able to assure that their facilities will consistently emit 
within the limits established during an ideally controlled initial 
performance test.
    Two of the commenters acknowledged that other MACT standards 
require the gathering of data for surrogate parameters (e.g., scrubber 
liquor pH, scrubber liquor flow) when direct measurement of a control 
parameter is not required or feasible. These surrogate parameters are 
used to establish performance requirements for the control device. The 
commenters went on to say that in cases where performance requirements 
based on surrogate parameters were established during the performance 
test, the emission limitation was not modified to reflect the actual 
emissions experience during the test. However, the commenters stated 
that they felt that this is exactly what is required under the proposed 
rule.
    One of the commenters argued that EPA's required installation of 
instruments directly in the vent stream to continuously monitor actual 
concentration of mercury and, therefore, actual mercury emissions, 
means that there is no need to rely on operating parameters which have 
been calculated for only one set of conditions.
    One commenter was concerned about the cost-benefits of continuous

[[Page 70923]]

monitoring systems (CMS) in the by-product hydrogen, end box 
ventilation system, and mercury thermal recovery unit vent streams. 
According to the commenter, the types of control devices likely to be 
used for controlling mercury emissions from these streams (i.e., carbon 
or molecular sieve units) have very good performance characteristics 
and are not likely to incur short-term upsets. The commenter noted that 
performance is subject to normal variations, and the ability of these 
systems to absorb mercury does degrade over time. The commenter stated 
that before emissions reach the permit limits due to reduced 
performance, the beds must be replaced. The commenter requested that in 
lieu of CMS, facilities should be allowed to rely on the known 
capability of the systems to operate reliably. The commenter stated 
that the Agency could delete the requirement for CMS without any real 
harm to the environment.
    Response: In general, we disagree with the premise of the 
commenters' argument. The proposed rule would have required that 
continuous compliance for each vent be determined by monitoring mercury 
concentration as an operating limit. The measured concentrations would 
not have been used to compare directly with the emission limitations. 
Rather, they would have provided an indication that the control device 
was performing in a manner consistent with the operation during the 
initial performance test. Therefore, the proposed requirements to 
establish operating limits would have established emission limitations, 
or resulted in changing emission limits, based on the initial 
performance test.
    However, we do acknowledge that there is a difference in a mercury 
concentration operating limit and an operating limit based on surrogate 
parameters because the mercury concentration is obviously a direct 
measure of mercury emissions. In fact, we agree with the point made by 
the one commenter that there is no need to rely on operating parameters 
when a direct measurement of emissions is being required.
    As discussed at length in the proposal preamble (67 FR 44690), we 
considered requiring mercury continuous emission monitors (CEM) that 
would directly measure in units of the standard. Although monitoring 
that directly measures compliance is preferred, we decided to propose 
mercury concentration operating limits based on the uncertainties 
associated with the cost and reliability of the mercury monitoring 
devices. Commenters did not provide any information to alleviate these 
concerns. In fact, they shared our basic concerns even if the 
monitoring devices were only used for operating limits.
    We weighed the comments related to the mercury concentration 
operating limits against the concerns associated with using mercury 
concentration monitors as CEM. Our preference continues to be to 
require mercury CEM. With sufficient evaluation, analysis, and 
refinement, the industry will find these devices acceptable. However, 
we could not require these devices in the final rule without a fallback 
alternative if sources found that these monitoring devices were not 
acceptable for use within the industry.
    During the development of the proposed standards, we learned that 
many mercury cell chlor-alkali facilities conducted periodic (e.g., 
weekly, monthly) tests to determine the mercury content in vent 
streams. This is done to assess control device performance or, for the 
by-product hydrogen stream, to ensure product quality. These tests are 
not typically conducted using EPA-approved test methods, but are 
usually conducted using modified methods. Since this periodic testing 
is already being conducted at many mercury cell plants, we evaluated 
whether a continuous compliance option could be included in the final 
rule based on such periodic testing. Since such testing directly 
measures mercury emissions, we concluded that it would be an acceptable 
alternative to mercury CEM. The only question was how often such 
testing would be needed to ensure continuous compliance with the 
emission limitations. Daily testing would certainly be adequate, but we 
were concerned about the costs and burden associated with 365 tests 
each year for each process vent.
    The most common final control device is (or will be) 
nonregenerative carbon adsorption. These fixed bed carbon devices can 
operate for long periods of time before a carbon change is needed. The 
carbon replacement frequency is often more than a year. Weekly testing 
would be more than sufficient to represent the emissions for the entire 
week and to indicate when breakthrough (i.e., the point at which the 
carbon has become saturated with mercury emissions) is approaching. 
Because breakthrough does not occur instantaneously, but is slowly 
approached over time, weekly testing is sufficient to detect the point 
at which breakthrough is approaching.
    However, there is the possibility that non-carbon devices such as 
condensers, absorbers, or regenerative molecular sieves could be used 
as the final control device to comply with the emission limits in the 
final rule. Since improper operation of these devices could result in 
higher emissions for short periods, we had concerns about utilizing 
weekly testing for these devices. However, we concluded that if 
parametric monitoring of surrogate parameters (e.g., condenser 
temperature) were conducted to ensure consistent and proper operation 
of these devices, weekly testing would be acceptable.
    Therefore, the final rule includes two options for continuous 
compliance for the by-product hydrogen stream, the end box ventilation 
system vent, and the mercury thermal recovery unit vent. The first 
option is continuous emissions monitoring using a mercury continuous 
emissions monitoring system. The second is periodic testing using 
Method 101, 101A, or 102 or an approved alternative method. 
Specifically, this second option requires that at least three 
acceptable test runs be conducted each week. As part of the periodic 
testing option, if the final control device is not a nonregenerative 
carbon adsorber, surrogate parameter monitoring is required.

V. What Are the Environmental, Cost, and Economic Impacts of the Final 
Rule?

A. What Are the Air Emission Impacts?

    The level of mercury emissions allowed by the Mercury NESHAP is 
2,300 grams per day. If one assumes that all nine plants in the source 
category emit mercury at this level, and that each operates 365 days a 
year, total annual potential-to-emit baseline emissions would be 7,556 
kg/yr (16,658 lb/yr). Annual potential-to-emit baseline emissions for 
fugitive emission sources would be 4,271 kg/yr (9,416 lb/yr), based on 
1,300 grams per day assumed for each plant's cell room ventilation 
system when the 18 design, maintenance, and housekeeping practices 
referenced in the Mercury NESHAP are followed. Annual potential-to-emit 
baseline emissions for by-product hydrogen streams, end box ventilation 
system vents, and mercury thermal recovery unit vents would be 3,285 
kg/yr (7,242 lb/yr), based on the remaining 1,000 grams per day 
allowed. We estimate that the final rule will reduce industrywide 
mercury emissions for by-product hydrogen streams, end box ventilation 
system vents, and mercury thermal recovery unit vents from this annual 
potential-to-emit baseline to around 217 kg/yr (478 lb/yr), which is 
equivalent to about 93 percent reduction.

[[Page 70924]]

    While the level of mercury emissions allowed by the Mercury NESHAP 
defines the potential-to-emit baseline, the sum of annual mercury 
emission releases from by-product hydrogen streams, end box ventilation 
system vents, and mercury thermal recovery vents, as estimated by 
mercury cell chlor-alkali plants, defines an annual actual baseline for 
vents of about 800 kg/yr (1,764 lb/yr). We estimate that the final rule 
will reduce industrywide mercury emissions for vents from this annual 
actual baseline to around 217 kg/yr (478 lb/yr), which is equivalent to 
about 73 percent reduction.
    We estimate that secondary air pollution emissions will result from 
the production of electricity required to operate new control devices 
and new monitoring equipment assumed for plant vents. Assuming 
electricity production as based entirely on coal combustion for a 
worst-case scenario, we estimated plant-specific impacts for sulfur 
dioxide, nitrogen oxides, particulate matter, and carbon monoxide 
emissions. The total estimated secondary air impacts of the final 
requirements for point sources at the nine mercury cell chlor-alkali 
plants is around 2.12 mg/yr (4.67 tpy) for all pollutants combined.
    We are unable to quantify the primary air emission impacts 
associated with the final work practice standards, so no mercury 
emission reduction is assumed for fugitive emission sources. However, 
we feel strongly that the new and more explicit requirements contained 
in the final standards will in fact result in mercury emission 
reductions beyond baseline levels. Relative to secondary impacts, we 
expect that secondary air pollution emissions will result from the 
production of electricity required to operate new monitoring equipment 
assumed for plant cell rooms. We estimate the secondary air impacts of 
the final rule for fugitive emission sources to be 0.112 mg/yr (0.124 
tpy).

B. What Are the Non-Air Health, Environmental, and Energy Impacts?

    We do not expect that there will be any significant adverse non-air 
health impacts associated with the final standards for mercury-cell 
chlor-alkali plants.
    We estimate that an increase in the amount of mercury-containing 
waters will result from the heightened use of packed tower scrubbing 
assumed for several plant vents. The total estimated water pollution 
impact of the final rule for point sources is about 1.5 million liters 
(404 thousand gallons) of additional wastewater per year. We estimate 
that an increase in the amount of mercury-containing solid wastes will 
result with the heightened use of carbon adsorption assumed for several 
plant vents. The total estimated solid waste impact of the final rule 
for point sources is about 8.8 mg/yr (9.7 tpy) of additional mercury-
containing spent carbon.
    We are unable to quantify non-air environmental impacts associated 
with the final work practice standards, so no wastewater and solid 
waste impacts are assumed for fugitive emission sources.
    We estimate that the final requirements for point sources will 
result in increased energy consumption, specifically additional fan 
power in conveying gas streams through new carbon adsorbers and new 
packed scrubbers assumed for certain plant vents and additional power 
consumed by new vent monitoring equipment. The total estimated energy 
impacts of the final requirements for point sources is about 772 
thousand kW-hr/yr.
    We estimate that the final requirements for fugitive emission 
sources will result in increased energy consumption required to operate 
new monitoring equipment assumed for plant cell rooms. The total 
estimated energy impacts of the final requirements for fugitive 
emission sources is about 39 thousand kW-hr/yr.

C. What Are the Cost and Economic Impacts?

    For projecting cost impacts of the final rule on the mercury cell 
chlor-alkali industry, we estimate that all nine plants will incur 
costs to meet the final work practice standards and the final 
monitoring, recordkeeping, and reporting requirements. We estimate that 
seven plants will incur costs to meet the final emission limits for by-
product hydrogen streams and end box ventilation system vents, and two 
plants will incur costs to meet the final emission limits for mercury 
thermal recovery units. The total estimated capital cost of the final 
rule for the nine mercury cell chlor-alkali plants is around $1.6 
million, and the total estimated annual cost is about $1.4 million per 
year. Plant-specific annual costs in our estimate range from about 
$130,000 for the least-impacted plant to about $260,000 for the worst-
impacted plant.
    The purpose of the economic impact analysis is to estimate the 
market response of chlor-alkali production facilities to the final 
standards and to determine the economic effects that may result due to 
the final NESHAP. Chlor-alkali production jointly creates both chlorine 
and caustic, usually sodium hydroxide, in fixed proportions. Being 
joint commodities, the economic analysis considers the impacts of the 
final NESHAP on both the chlorine and sodium hydroxide markets.
    The chlor-alkali production source category contains 43 facilities, 
but only nine facilities using mercury cells are directly affected by 
the final standards. These nine facilities are located at nine plants 
that are owned by seven companies.
    Chlor-alkali production in mercury cells leads to potential mercury 
emissions from hydrogen streams, end box ventilation system vents, 
mercury thermal recovery units, and fugitive emission sources. The 
compliance costs for the final standards, therefore, relate to the 
purchase, installation, operation, and maintenance of pollution control 
equipment at the point sources, as well as the labor costs and 
overheads associated with observing work practices addressing fugitive 
emissions. The estimated total annual costs for the final NESHAP are 
$1.8 million. This cost estimate represents about 0.30 percent of the 
1997 chlorine sales revenue for the mercury cell chlor-alkali 
production facilities. Furthermore, the total annual costs represent 
less than 0.01 percent of the revenues of owning the directly affected 
mercury cell chlor-alkali plants.
    The economic analysis predicts minimal changes in industry outputs 
and the market prices of chlorine and sodium hydroxide as a result of 
the estimated control costs. The new market equilibrium quantities of 
chlorine and sodium hydroxide decrease by less than 0.1 percent. 
Equilibrium prices of chlorine and sodium hydroxide both rise by less 
than 0.1 percent due to the final standards. Based on these estimates, 
we conclude that the final standards are not likely to have a 
significant economic impact on the chlorine production industry as a 
whole or on secondary markets such as the labor market and foreign 
trade.
    We performed an economic analysis to determine facility- and 
company-specific impacts. These economic impacts are measured by 
calculating the ratio of the estimated annualized compliance costs of 
emissions control for each entity to its revenues (i.e., cost-to-sales 
ratio). After the cost-to-sales ratio is calculated for each entity, it 
is then multiplied by 100 to convert the ratio into percentages. Actual 
revenues at the facility level are not available, therefore, estimated 
facility revenues received from the sale of chlorine are used. Some of 
these facilities also produce caustic as potassium hydroxide, but the 
revenues from the sale of this product are not estimated. The nine 
mercury cell chlor-alkali

[[Page 70925]]

plants have positive cost-to-sales ratios. The ratio of costs to 
estimated chlorine sales revenue for these facilities range from a low 
of 0.16 percent to a high of 1.00 percent. The average cost-to-sales 
ratio for the nine mercury process chlorine production facilities is 
0.46 percent. More detailed economic analysis predicted minimal changes 
in chlorine production at each facility. Thus, overall, the economic 
impact of the final standards is minimal for the facilities producing 
chlorine.
    The share of compliance costs to company sales are calculated to 
determine company level impacts. Since seven companies own the nine 
affected facilities, all seven firms face positive compliance costs 
from the final NESHAP. The ratio of costs to estimated revenues range 
from a low of less than 0.01 percent to a high of 0.22 percent, and the 
average ratio of costs to company revenues is 0.06 percent. Again, more 
detailed economic analysis at the company level predicts little change 
in company output or revenues. So, at the company level, the final 
standards are not anticipated to have a significant economic impact on 
companies that own and operate the chlorine production facilities.
    No facility or company is expected to close as a result of the 
final standards, and the economic impacts to consumers are anticipated 
to be minimal. The generally small scale of the impacts suggests that 
there will also be no significant impacts on markets for the products 
made using chlorine or sodium hydroxide. For more information, consult 
the economic impact analysis report entitled ``Economic Impact Analysis 
for the Final Mercury Cell Chlor-Alkali Production NESHAP,'' which is 
available in the docket for this rulemaking.

VI. Statutory and Executive Order Reviews

A. Executive Order 12866--Regulatory Planning and Review

    Under Executive Order 12866 (58 FR 51735, October 4, 1993), the 
Agency must determine whether the regulatory action is ``significant'' 
and therefore subject to Office of Management and Budget (OMB) review 
and the requirements of the Executive Order. The Executive Order 
defines ``significant regulatory action'' as one that is likely to 
result in a rule that may:
    (1) Have an annual effect on the economy of $100 million or more or 
adversely affect in a material way the economy, a sector of the 
economy, productivity, competition, jobs, the environment, public 
health or safety, or State, local, or tribal governments or 
communities;
    (2) create a serious inconsistency or otherwise interfere with an 
action taken or planned by another agency;
    (3) materially alter the budgetary impact of entitlements, grants, 
user fees, or loan programs, or the rights and obligation of recipients 
thereof; or
    (4) raise novel legal or policy issues arising out of legal 
mandates, the President's priorities, or the principles set forth in 
the Executive Order.
    It has been determined that the final rule is not a ``significant 
regulatory action'' under the terms of Executive Order 12866 and is, 
therefore, not subject to OMB review.

B. Paperwork Reduction Act

    The information collection requirements in the final rule have been 
submitted for approval to OMB under the requirements of the Paperwork 
Reduction Act, 44 U.S.C. 3501 et seq. The information requirements are 
not enforceable until OMB approves them.
    The information requirements are based on notifications, records, 
and reports required by the General Provisions (40 CFR part 63, subpart 
A), which are mandatory for all operators subject to national emission 
standards. These recordkeeping and reporting requirements are 
specifically authorized under section 114 of the CAA (42 U.S.C. 7414). 
All information submitted to the EPA pursuant to the recordkeeping and 
reporting requirements for which a claim of confidentiality is made 
will be safeguarded according to Agency policies in 40 CFR part 2, 
subpart B, Confidentiality of Business Information.
    According to the ICR, the total 3-year monitoring, reporting, and 
recordkeeping burden for this collection is 6,692 labor hours, and the 
annual average burden is 2,231 labor hours. The total annualized cost 
of monitoring, reporting, and recordkeeping is approximately $628,212. 
The labor cost over the 3-year period is $295,928 or $98,643 per year. 
The annualized capital cost for monitoring equipment is $262,458. 
Annual operation and maintenance costs are $365,754 over 3 years, 
averaging $121,918 per year. This estimate includes a one-time plan for 
demonstrating compliance, annual compliance certificate reports, 
notifications, and recordkeeping.
    Burden means the total time, effort, or financial resources 
expended by persons to generate, maintain, retain, or disclose or 
provide information to or for a Federal agency. This includes the time 
needed to review instructions; develop, acquire, install, and utilize 
technology and systems for the purpose of collecting, validating, and 
verifying information; process and maintain information and disclose 
and provide information; adjust the existing ways to comply with any 
previously applicable instructions and requirements; train personnel to 
respond to a collection of information; search existing data sources; 
complete and review the collection of information; and transmit or 
otherwise disclose the information.
    An agency may not conduct or sponsor, and a person is not required 
to respond to, a collection of information unless it displays a 
currently valid OMB control number. The OMB control numbers for EPA's 
regulations are listed in 40 CFR part 9 and 48 CFR chapter 15. The OMB 
control number(s) for the information collection requirements in the 
final rule will be listed in an amendment to 40 CFR part 9 or 48 CFR 
chapter 15 in a subsequent Federal Register document after OMB approves 
the ICR.

C. Regulatory Flexibility Act

    The EPA has determined that it is not necessary to prepare a 
regulatory flexibility analysis in connection with the final rule. The 
EPA has also determined that the final rule will not have a significant 
economic impact on a substantial number of small entities. For purposes 
of assessing the impacts of today's final rule on small entities, small 
entity is defined as: (1) A small business according to the Small 
Business Administration (SBA) size standards by NAICS code, a maximum 
of 1,000 employees for the alkalies and chlorine manufacturing 
industry; (2) a small governmental jurisdiction that is a government of 
a city, county, town, school district or special district with a 
population of less than 50,000; and (3) a small organization that is 
any not-for-profit enterprise which is independently owned and operated 
and is not dominant in its field.
    After considering the economic impacts of today's final rule on 
small entities, EPA has concluded that this action will not have a 
significant economic impact on a substantial number of small entities. 
We have determined that two of the seven companies that own mercury 
chlor-alkali plants are small entities. Although small businesses 
represent 30 percent of the companies within the source category, they 
are expected to incur 18 percent of the total industry annual 
compliance costs. There are no companies with compliance costs equal to 
or greater than 1 percent of their sales. No firms are expected to 
close rather than incur the costs of compliance with the final rule.

[[Page 70926]]

Furthermore, firms are not projected to close their facilities due to 
the final rule.
    Although the final rule will not have significant economic impact 
on a substantial number of small entities, we have nonetheless worked 
aggressively to minimize the impact of the final rule on small 
entities, consistent with our obligation under the CAA. The two 
companies have been active participants in the rulemaking process 
through their association with the industry trade organization, the 
Chlorine Institute. Therefore, we met with representatives of these 
small entities on numerous occasions. In addition, we conducted an 
extended visit to a mercury cell chlor-alkali plant owned by one of 
these companies to understand their process and emission control 
techniques, along with any unique impacts that might occur due to the 
fact that their company was a small entity. In general, the provisions 
of the rule were deigned to achieve the maximum emission reduction 
while also incorporating as many of the existing practices currently 
being employed by the industry. The input received from these small 
entities was duly considered in this evaluation.

D. Unfunded Mandates Reform Act of 1995

    Title II of the Unfunded Mandates Reform Act of 1995 (UMRA), Public 
Law 104-4, establishes requirements for Federal agencies to assess the 
effects of their regulatory actions on State, local, and tribal 
governments and the private sector. Under section 202 of the UMRA, we 
generally must prepare a written statement, including cost-benefit 
analysis, for proposed and final rules with ``Federal mandates'' that 
may result in expenditures to State, local, and Tribal governments, in 
the aggregate, or to the private sector, of $100 million or more in any 
1 year. Before promulgating an EPA rule for which a written statement 
is needed, section 205 of the UMRA generally requires us to identify 
and consider a reasonable number of regulatory alternatives and adopt 
the least costly, most cost-effective, or least burdensome alternative 
that achieves the objectives of the rule. The provisions of section 205 
do not apply when they are inconsistent with applicable law. Moreover, 
section 205 allows us to adopt an alternative other than the least 
costly, most cost-effective, or least burdensome alternative if we 
publish with the final rule an explanation why that alternative was not 
adopted.
    Before we establish any regulatory requirements that may 
significantly or uniquely affect small governments, including Tribal 
governments, we must have developed under section 203 of the UMRA a 
small government agency plan. The plan must provide for notifying 
potentially affected small governments, enabling officials of affected 
small governments to have meaningful and timely input in the 
development of our regulatory proposals with significant Federal 
intergovernmental mandates, and informing, educating, and advising 
small governments on compliance with the regulatory requirements.
    We have determined that the final rule does not contain a Federal 
mandate that may result in expenditures of $100 million or more for 
State, local, or tribal governments, in the aggregate, or the private 
sector in any 1 year. The total annualized cost of the final rule has 
been estimated to be $1,390,000. Thus, today's final rule is not 
subject to the requirements of sections 202 and 205 of the UMRA. In 
addition, we have determined that the final rule contains no regulatory 
requirements that might significantly or uniquely affect small 
governments because it contains no regulatory requirements that apply 
to such governments or impose obligations upon them. Therefore, the 
final rule is not subject to the requirements of section 203 of the 
UMRA.

E. Executive Order 13132--Federalism

    Executive Order 13132, entitled ``Federalism'' (64 FR 43255, August 
10, 1999), requires EPA to develop an accountable process to ensure 
``meaningful and timely input by State and local officials in the 
development of regulatory policies that have federalism implications.'' 
``Policies that have federalism implications'' are defined in the 
Executive Order to include regulations that have ``substantial direct 
effects on the States, on the relationship between the national 
Government and the States, or on the distribution of power and 
responsibilities among the various levels of Government.''
    The final rule does not have federalism implications. It will not 
have substantial direct effects on the States, on the relationship 
between the national Government and the States, or on the distribution 
of power and responsibilities among the various levels of Government, 
as specified in Executive Order 13132. The standards apply only to 
mercury cell chlor-alkali plants and do not pre-exempt States from 
adopting more stringent standards or otherwise regulate State or local 
governments. Thus, Executive Order 13132 does not apply to the final 
rule.
    Although section 6 of Executive Order 13132 does not apply to the 
final rule, EPA did consult with State and local officials in 
developing the final rule. No concerns were raised by these officials 
during this consultation.

F. Executive Order 13175--Consultation and Coordination With Indian 
Tribal Governments

    Executive Order 13175, entitled ``Consultation and Coordination 
with Indian Tribal Governments'' (65 FR 67249, November 6, 2000), 
requires EPA to develop an accountable process to ensure ``meaningful 
and timely input by tribal officials in the development of regulatory 
policies that have tribal implications.'' ``Policies that have tribal 
implications'' are defined in the Executive Order to include 
regulations that have ``substantial direct effects on one or more 
Indian tribes, on the relationship between the Federal government and 
the Indian tribes, or on the distribution of power and responsibilities 
between the Federal government and Indian tribes.''
    The final rule does not have tribal implications. It will not have 
substantial direct effects on tribal governments, on the relationship 
between the Federal government and Indian tribes, or on the 
distribution of power and responsibilities between the Federal 
government and Indian tribes, as specified in Executive Order 13175. 
This is because no tribal governments own or operate a mercury cell 
chlor-alkali plant. Thus, Executive Order 13175 does not apply to the 
final rule.

G. Executive Order 13045--Protection of Children From Environmental 
Health Risks and Safety Risks

    Executive Order 13045, ``Protection of Children from Environmental 
Health Risks and Safety Risks'' (62 FR 19885, April 23, 1997) applies 
to any rule that (1) is determined to be ``economically significant'' 
as defined under Executive Order 12866, and (2) concerns an 
environmental health or safety risk that EPA has reason to believe may 
have a disproportionate effect on children. If the regulatory action 
meets both criteria, the Agency must evaluate the environmental health 
or safety effects of the planned rule on children and explain why the 
planned rule is preferable to other potentially effective and 
reasonably feasible alternatives that we considered.
    The final rule is not subject to Executive Order 13045 because it 
is not an economically significant regulatory action as defined by 
Executive Order 12866. In addition, EPA interprets Executive Order 
13045 as applying only to those regulatory actions that are based on 
health and safety risks, such that the analysis required under section

[[Page 70927]]

5-501 of the Executive Order has the potential to influence the 
regulation.
    As with most rulemakings developed under section 112(d) of the CAA, 
the final rule is based on MACT. Risks to public health and impacts on 
the environment are not typically considered in the development of 
emissions standards under section 112(d). Rather, these risks and 
impacts are considered later (within 8 years after promulgation of the 
MACT rule) under the residual risk program as required by section 
112(f) of the CAA. While we do not believe the final rule to be 
``economically significant,'' as defined under Executive Order 12866, 
we do believe that it addresses environmental health or safety risks 
that may have a disproportionate effect on children.
    Mercury has been identified as a priority pollutant under EPA's 
National Agenda to Protect Children's Health from Environmental Threats 
and by the Federal Children's Health Protection Advisory Committee 
(CHPAC). The CHPAC was formed to advise, consult with, and make 
recommendations to EPA on issues associated with the development of 
regulations to address the prevention of adverse health effects to 
children. One of the CHPAC's primary missions was to identify five 
existing EPA regulations, which if reevaluated, could lead to better 
protection for children. The CHPAC recommended the Mercury NESHAP for 
chlor-alkali plants as one of the regulations to be reevaluated 
considering impacts on children. We adopted the CHPAC recommendation. 
Therefore, we considered the impacts on children in the development of 
the final rule. A qualitative assessment of the potential impacts on 
children's health due to mercury emissions from chlor-alkali plants was 
presented in the preamble to the proposed rule (67 FR 44693).
    Because the final rule does not meet both criteria for 
applicability, it is not subject to Executive Order 13045. However, 
based on our assessment, the final rule will help reduce the mercury 
exposures to humans, including children.

H. Executive Order 13211--Actions Concerning Regulations That 
Significantly Affect Energy Supply, Distribution, or Use

    The final rule is not subject to Executive Order 13211, ``Actions 
Concerning Regulations That Significantly Affect Energy Supply, 
Distribution, or Use'' (66 FR 28355, May 22, 2001) because it is not a 
significant regulatory action under Executive Order 12866.

I. National Technology Transfer and Advancement Act of 1995

    Section 12(d) of the National Technology Transfer and Advancement 
Act (NTTAA) of 1995 (Public Law No. 104-113; 15 U.S.C. 272 note) 
directs EPA to use voluntary consensus standards in their regulatory 
and procurement activities unless to do so would be inconsistent with 
applicable law or otherwise impractical. Voluntary consensus standards 
are technical standards (e.g., materials specifications, test methods, 
sampling procedures, business practices) developed or adopted by one or 
more voluntary consensus bodies. The NTTAA directs EPA to provide 
Congress, through annual reports to the OMB, with explanations when an 
agency does not use available and applicable voluntary consensus 
standards.
    The final rule involves technical standards. The EPA cites in the 
final rule EPA Methods 1, 1A, 2, 2A, 2C, 2D, 3, 3A, 3B, 4, 5, 101, 
101A, 102, and any method to measure mercury (validated with EPA Method 
301). Consistent with the NTTAA, EPA conducted searches to identify 
voluntary consensus standards in addition to these EPA methods. No 
applicable voluntary consensus standards were identified for EPA 
Methods 1A, 2A, 2D, and 102. The search and review results have been 
documented and are placed in the docket (OAR-2002-0017 or A-2000-32) 
for the final rule.
    This search for emissions monitoring procedures identified 14 
voluntary consensus standards and five draft standards. The EPA 
determined that the 14 standards were impractical alternatives to EPA 
test methods for the purposes of this rulemaking. Therefore, EPA will 
not adopt these standards today. The reasons for this determination for 
these 14 standards are in the docket.
    The 14 voluntary consensus standards are as follows: ASME C00031 or 
PTC 19-10-1981, ``Part 10 Flue and Exhaust Gas Analyses,'' for EPA 
Method 3; ASME PTC-38-80 R85 or C00049, ``Determination of the 
Concentration of Particulate Matter in Gas Streams,'' for EPA Method 5; 
ASTM D3154-91 (1995), ``Standard Method for Average Velocity in a Duct 
(Pitot Tube Method),'' for EPA Methods 1, 2, 2C, 3, 3B, and 4; ASTM 
D3464-96, ``Standard Test Method Average Velocity in a Duct Using a 
Thermal Anemometer,'' for EPA Method 2; ASTM D3685/D3685M-98, ``Test 
Methods for Sampling and Determination of Particulate Matter in Stack 
Gases,'' for EPA Method 5; ASTM D3796-90 (1998), ``Standard Practice 
for Calibration of Type S Pitot Tubes,'' for EPA Method 2; ASTM D5835-
95, ``Standard Practice for Sampling Stationary Source Emissions for 
Automated Determination of Gas Concentration,'' for EPA Methods 3A; 
ASTM E337-84 (Reapproved 1996), ``Standard Test Method for Measuring 
Humidity with a Psychrometer (the Measurement of Wet- and Dry-Bulb 
Temperatures),'' for EPA Method 4; CAN/CSA Z223.1-M1977, ``Method for 
the Determination of Particulate Mass Flows in Enclosed Gas Streams,'' 
for EPA Method 5; CAN/CSA Z223.2-M86 (1986), ``Method for the 
Continuous Measurement of Oxygen, Carbon Dioxide, Carbon Monoxide, 
Sulphur Dioxide, and Oxides of Nitrogen in Enclosed Combustion Flue Gas 
Streams,'' for EPA Methods 3A; CAN/CSA Z223.26-M1987, ``Measurement of 
Total Mercury in Air Cold Vapour Atomic Absorption Spectrophotometeric 
Method,'' for EPA Methods 101 and 101A; ISO 9096:1992 (in review 2000), 
``Determination of Concentration and Mass Flow Rate of Particulate 
Matter in Gas Carrying Ducts--Manual Gravimetric Method,'' for EPA 
Method 5; ISO 10396:1993, ``Stationary Source Emissions: Sampling for 
the Automated Determination of Gas Concentrations,'' for EPA Method 3A; 
ISO 10780:1994, ``Stationary Source Emissions--Measurement of Velocity 
and Volume Flowrate of Gas Streams in Ducts,'' for EPA Method 2.
    The following five standards identified in this search were not 
available at the time the review was conducted for the purposes of this 
rulemaking because they are under development by a voluntary consensus 
body: ASME/BSR MFC 12M, ``Flow in Closed Conduits Using Multiport 
Averaging Pitot Primary Flowmeters,'' for EPA Method 2; ASME/BSR MFC 
13M, ``Flow Measurement by Velocity Traverse,'' for EPA Method 2 (and 
possibly 1); ISO/DIS 12039, ``Stationary Source Emissions--
Determination of Carbon Monoxide, Carbon Dioxide, and Oxygen--Automated 
Methods,'' for EPA Method 3A; PREN 13211 (1998), ``Air Quality--
Stationary Source Emissions--Determination of the Concentration of 
Total Mercury,'' for EPA Methods 101, 101A (and mercury portion of EPA 
Method 29); and ASTM Z6590Z, ``Manual Method for Both Speciated and 
Elemental Mercury'' is a potential alternative for portions of EPA 
Methods 101A and Method 29 (mercury portion only).
    Section 63.8232 of the final rule lists the EPA testing methods 
included in the final rule. Under 40 CFR 63.7(f) and 63.8(f), a source 
may apply to EPA for

[[Page 70928]]

permission to use alternative test methods or alternative monitoring 
requirements in place of any of the EPA testing methods, performance 
specifications, or procedures.

J. Congressional Review Act

    The Congressional Review Act, 5 U.S.C. 801 et seq., as added by the 
Small Business Regulatory Enforcement Fairness Act of 1996, generally 
provides that before a rule may take effect, the agency promulgating 
the rule must submit a rule report, which includes a copy of the rule, 
to each House of the Congress and to the Comptroller General of the 
United States. The EPA will submit a report containing this rule and 
other required information to the U.S. Senate, the U.S. House of 
Representatives, and the Comptroller General of the United States prior 
to publication of the rule in the Federal Register. This action is not 
a ``major rule'' as defined by 5 U.S.C. 804(2). The final rule will be 
effective on December 19, 2003.

List of Subjects in 40 CFR Part 63

    Environmental protection, Administrative practice and procedure, 
Air pollution control, Hazardous substances, Intergovernmental 
relations, Recordkeeping and reporting requirements.

    Dated: August 25, 2003.
Marianne Lamont Horinko,
Acting Administrator.

0
For the reasons stated in the preamble, title 40, chapter I, part 63 of 
the Code of Federal Regulations is amended as follows:

PART 63--[AMENDED]

0
1. The authority citation for part 63 continues to read as follows:

    Authority: 42 U.S.C. 7401, et seq.


0
2. Part 63 is amended by adding subpart IIIII to read as follows:

Subpart IIIII--National Emission Standards for Hazardous Air 
Pollutants: Mercury Emissions From Mercury Cell Chlor-Alkali Plants

Sec.

What This Subpart Covers

63.8180 What is the purpose of this subpart?
63.8182 Am I subject to this subpart?
63.8184 What parts of my plant does this subpart cover?
63.8186 When do I have to comply with this subpart?

Emission Limitations and Work Practice Standards

63.8190 What emission limitations must I meet?
63.8192 What work practice standards must I meet?

Operation and Maintenance Requirements

63.8222 What are my operation and maintenance requirements?

General Compliance Requirements

63.8226 What are my general requirements for complying with this 
subpart?

Initial Compliance Requirements

63.8230 By what date must I conduct performance tests or other 
initial compliance demonstrations?
63.8232 What test methods and other procedures must I use to 
demonstrate initial compliance with the emission limits?
63.8234 What equations and procedures must I use for the initial 
compliance demonstration?
63.8236 How do I demonstrate initial compliance with the emission 
limitations and work practice standards?

Continuous Compliance Requirements

63.8240 What are my monitoring requirements?
63.8242 What are the installation, operation, and maintenance 
requirements for my continuous monitoring systems?
63.8243 What equations and procedures must I use to demonstrate 
continuous compliance?
63.8244 How do I monitor and collect data to demonstrate continuous 
compliance?
63.8246 How do I demonstrate continuous compliance with the emission 
limitations and work practice standards?
63.8248 What other requirements must I meet?

Notifications, Reports, and Records

63.8252 What notifications must I submit and when?
63.8254 What reports must I submit and when?
63.8256 What records must I keep?
63.8258 In what form and how long must I keep my records?

Other Requirements and Information

63.8262 What parts of the General Provisions apply to me?
63.8264 Who implements and enforces this subpart?
63.8266 What definitions apply to this subpart?

Tables to Subpart IIIII of Part 63

Table 1 to Subpart IIIII of Part 63--Work Practice Standards--
Design, Operation, and Maintenance Requirements
Table 2 to Subpart IIIII of Part 63--Work Practice Standards--
Required Inspections
Table 3 to Subpart IIIII of Part 63--Work Practice Standards--
Required Actions for Liquid Mercury Spills and Accumulations and 
Hydrogen and Mercury Vapor Leaks
Table 4 to Subpart IIIII of Part 63--Work Practice Standards--
Requirements for Mercury Liquid Collection
Table 5 to Subpart IIIII of Part 63--Required Elements of Floor-
Level Mercury Vapor Measurement and Cell Room Monitoring Plans
Table 6 to Subpart IIIII of Part 63--Examples of Techniques for 
Equipment Problem Identification, Leak Detection and Mercury Vapor 
Measurements
Table 7 to Subpart IIIII of Part 63--Required Elements of Washdown 
Plans
Table 8 to Subpart IIIII of Part 63--Requirements for Cell Room 
Monitoring Program
Table 9 to Subpart IIIII of Part 63--Required Records for Work 
Practice Standards
Table 10 to Subpart IIIII of Part 63--Applicability of General 
Provisions to Subpart IIIII

What This Subpart Covers


Sec.  63.8180  What is the purpose of this subpart?

    This subpart establishes national emission standards for hazardous 
air pollutants (NESHAP) for affected sources of mercury emissions at 
mercury cell chlor-alkali plants. This subpart also establishes 
requirements to demonstrate initial and continuous compliance with all 
applicable emission limitations and work practice standards in this 
subpart.


Sec.  63.8182  Am I subject to this subpart?

    (a) You are subject to this subpart if you own or operate a mercury 
cell chlor-alkali plant.
    (b) You are required to obtain a title V permit, whether your 
affected source is a part of a major source of hazardous air pollutant 
(HAP) emissions or a part of an area source of HAP emissions. A major 
source of HAP is a source that emits or has the potential to emit any 
single HAP at a rate of 10 tons or more per year or any combination of 
HAP at a rate of 25 tons or more per year. An area source of HAP is a 
source that has the potential to emit HAP but is not a major source. 
Nothing in this subpart revises how affected sources are aggregated for 
purposes of determining whether an affected source is a part of an 
area, nonmajor, or major source under any provisions of the Clean Air 
Act (CAA) or EPA's regulations. For information on aggregating affected 
sources to determine what is a source under title V, see the definition 
of major source in 40 CFR 70.2, 71.2 and 63.2.
    (c) Beginning on December 19, 2006, the provisions of subpart E of 
40 CFR part 61 that apply to mercury chlor-alkali plants, which are 
listed in paragraphs (c)(1) through (3) of this section, are no longer 
applicable.
    (1) Sec.  61.52(a);
    (2) Sec.  61.53(b) and (c); and

[[Page 70929]]

    (3) Sec.  61.55(b), (c) and (d).


Sec.  63.8184  What parts of my plant does this subpart cover?

    (a) This subpart applies to each affected source at a plant site 
where chlorine and caustic are produced in mercury cells. This subpart 
applies to two types of affected sources: the mercury cell chlor-alkali 
production facility, as defined in paragraph (a)(1) of this section; 
and the mercury recovery facility, as defined in paragraph (a)(2) of 
this section.
    (1) The mercury cell chlor-alkali production facility designates an 
affected source consisting of all cell rooms and ancillary operations 
used in the manufacture of product chlorine, product caustic, and by-
product hydrogen at a plant site. This subpart covers mercury emissions 
from by-product hydrogen streams, end box ventilation system vents, and 
fugitive emission sources associated with cell rooms, hydrogen systems, 
caustic systems, and storage areas for mercury-containing wastes.
    (2) The mercury recovery facility designates an affected source 
consisting of all processes and associated operations needed for 
mercury recovery from wastes at a plant site. This subpart covers 
mercury emissions from mercury thermal recovery unit vents and fugitive 
emission sources associated with storage areas for mercury-containing 
wastes.
    (b) An affected source at your mercury cell chlor-alkali plant is 
existing if you commenced construction of the affected source before 
July 3, 2002.
    (c) A mercury recovery facility is a new affected source if you 
commence construction or reconstruction of the affected source after 
July 3, 2002. An affected source is reconstructed if it meets the 
definition of ``reconstruction'' in Sec.  63.2.


Sec.  63.8186  When do I have to comply with this subpart?

    (a) If you have an existing affected source, you must comply with 
each emission limitation, work practice standard, and recordkeeping and 
reporting requirement in this subpart that applies to you no later than 
December 19, 2006.
    (b) If you have a new or reconstructed mercury recovery facility 
and its initial startup date is on or before December 19, 2003, you 
must comply with each emission limitation, work practice standard, and 
recordkeeping and reporting requirement in this subpart that applies to 
you by December 19, 2003.
    (c) If you have a new or reconstructed mercury recovery facility 
and its initial startup date is after December 19, 2003, you must 
comply with each emission limitation, work practice standard, and 
recordkeeping and reporting requirement in this subpart that applies to 
you upon initial startup.
    (d) You must meet the notification and schedule requirements in 
Sec.  63.8252. Several of these notifications must be submitted before 
the compliance date for your affected source(s).

Emission Limitations and Work Practice Standards


Sec.  63.8190  What emission limitations must I meet?

    (a) Emission limits. You must meet each emission limit in 
paragraphs (a)(1) through (3) of this section that applies to you.
    (1) New or reconstructed mercury cell chlor-alkali production 
facility. Emissions of mercury are prohibited from a new or 
reconstructed mercury cell chlor-alkali production facility.
    (2) Existing mercury cell chlor-alkali production facility. During 
any consecutive 52-week period, you must not discharge to the 
atmosphere total mercury emissions in excess of the applicable limit in 
paragraph (a)(2)(i) or (ii) of this section calculated using the 
procedures in Sec.  63.8243(a).
    (i) 0.076 grams of mercury per megagram of chlorine produced (1.5 x 
10-4 pounds of mercury per ton of chlorine produced) from 
all by-product hydrogen streams and all end box ventilation system 
vents when both types of emission points are present.
    (ii) 0.033 grams of mercury per megagram of chlorine produced (6.59 
x 10-5 pounds of mercury per ton of chlorine produced) from 
all by-product hydrogen streams when end box ventilation systems are 
not present.
    (3) New, reconstructed, or existing mercury recovery facility. You 
must not discharge to the atmosphere mercury emissions in excess of the 
applicable limit in paragraph (a)(3)(i) or (ii) of this section.
    (i) 23 milligrams per dry standard cubic meter from each oven type 
mercury thermal recovery unit vent.
    (ii) 4 milligrams per dry standard cubic meter from each non-oven 
type mercury thermal recovery unit vent.
    (b) [Reserved]


Sec.  63.8192  What work practice standards must I meet?

    You must meet the work practice requirements specified in 
paragraphs (a) through (f) of this section. As an alternative to the 
requirements specified in paragraphs (a) through (d) of this section, 
you may choose to comply with paragraph (g) of this section.
    (a) You must meet the work practice standards in Tables 1 through 4 
to this subpart, except as specified in paragraph (g) of this section.
    (b) You must adhere to the response intervals specified in Tables 1 
through 4 to this subpart at all times. Nonadherence to the intervals 
in Tables 1 through 4 to this subpart constitutes a deviation and must 
be documented and reported in the compliance report, as required by 
Sec.  63.8254(b), with the date and time of the deviation, cause of the 
deviation, a description of the conditions, and time actual compliance 
was achieved.
    (c) As provided in Sec.  63.6(g), you may request to use an 
alternative to the work practice standards in Tables 1 through 4 to 
this subpart.
    (d) You must institute a floor-level mercury vapor measurement 
program to limit the amount of mercury vapor in the cell room 
environment through periodic measurement of mercury vapor levels and 
actions to be taken when a floor-level mercury concentration action 
level is exceeded. The program must meet the requirements listed in 
paragraphs (d)(1) through (4) of this section. As specified in Sec.  
63.8252(e)(1)(i) to implement this program, you must prepare and submit 
to the Administrator a floor-level mercury vapor measurement plan which 
must contain the elements listed in Table 5 to this subpart.
    (1) You must utilize a mercury measurement device described in of 
Table 6 to this subpart to measure the level of mercury vapor in the 
cell room at floor-level.
    (2) You must conduct at least one floor-level mercury vapor 
measurement evaluation each half day. This evaluation must include 
three measurements of the mercury concentration at locations 
representative of the entire cell room floor area. The average of these 
measurements must be recorded as specified in Sec.  63.8156(c)(1). At a 
minimum, you must measure the level of mercury vapor above mercury-
containing cell room equipment, as well as areas around the cells, 
decomposers, or other mercury-containing equipment.
    (3) You must establish a floor-level mercury concentration action 
level that is no higher than 0.05 milligrams per cubic meter (mg/m\3\).
    (4) If a mercury concentration greater than the action level is 
measured during any floor-level mercury vapor measurement evaluation, 
you must meet the requirements in either paragraph (d)(4)(i) or (ii) of 
this section.
    (i) If you determine that the cause of the elevated mercury 
concentration is an open electrolyzer, decomposer, or

[[Page 70930]]

other maintenance activity, you must record the information specified 
in paragraphs (d)(4)(i)(A) through (C) of this section.
    (A) A description of the maintenance activity resulting in elevated 
mercury concentration;
    (B) The time the maintenance activity was initiated and completed; 
and
    (C) A detailed explanation how all the applicable requirements of 
Table 1 to this subpart were met during the maintenance activity.
    (ii) If you determine that the cause of the elevated mercury 
concentration is not an open electrolyzer, decomposer, or other 
maintenance activity, you must follow the procedures specified in 
paragraphs (d)(4)(ii)(A) and (B) of this section until the floor-level 
mercury concentration falls below the floor-level mercury concentration 
action level. You must also keep all the associated records for these 
procedures as specified in Table 9 to this subpart.
    (A) Within 1 hour of the time the floor-level mercury concentration 
action level was exceeded, you must conduct each inspection specified 
in Table 2 to this subpart in the area where the concentration higher 
than the floor-level mercury concentration action level was measured, 
with the exception of the cell room floor and the pillars and beam 
inspections. (B) You must also inspect all decomposers, hydrogen system 
piping up to the hydrogen header, and other potential locations of 
mercury vapor leaks in the area using a technique specified in Table 6 
to this subpart. You must correct any problem identified during these 
inspections according to the requirements in Tables 2 and 3 to this 
subpart.
    (e) You must prepare, submit, and operate according to a written 
washdown plan designed to minimize fugitive mercury emissions through 
routine washing of surfaces where liquid mercury could accumulate. The 
written plan must address the elements contained in Table 7 to this 
subpart.
    (f) You must keep records of the mass of all virgin mercury added 
to cells on an annual basis.
    (g) As an alternative to the work practice standards in paragraphs 
(a) through (d) of this section, you may institute a cell room 
monitoring program to continuously monitor the mercury vapor 
concentration in the upper portion of each cell room and to take 
corrective actions as quickly as possible when elevated mercury vapor 
levels are detected. As specified in Sec.  63.8252(e)(1)(iv), if you 
choose this option, you must prepare and submit to the Administrator, a 
cell room monitoring plan containing the elements listed in Table 5 to 
this subpart and meet the requirements in paragraphs (g)(1) through (4) 
of this section.
    (1) You must utilize mercury monitoring systems that meet the 
requirements of Table 8 to this subpart.
    (2) You must establish an action level according to the 
requirements in paragraphs (g)(2)(i) through (iii) of this section.
    (i) Beginning on the compliance date specified for your affected 
source in Sec.  63.8186, measure and record the mercury concentration 
for at least 30 days using a system that meets the requirements of 
paragraph (g)(1) of this section.
    (ii) Using the monitoring data collected according to paragraph 
(g)(1)(i) of this section, establish your action level at the 75th 
percentile of the data set.
    (iii) Submit your action level as part of your Notification of 
Compliance Status report according to Sec.  63.8252(e)(1).
    (3) Beginning on the compliance date specified for your affected 
source in Sec.  63.8186, you must continuously monitor the mercury 
concentration in the cell room. Failure to monitor and record the data 
according to Sec.  63.8256(c) (4)(ii) for 75 percent of the time in any 
6-month period constitutes a deviation.
    (4) If the average mercury concentration for any 1-hour period 
exceeds the action level established according to paragraph (g)(2) of 
this section, you must meet the requirements in either paragraph 
(g)(4)(i) or (ii) of this section.
    (i) If you determine that the cause of the elevated mercury 
concentration is an open electrolyzer, decomposer, or other maintenance 
activity, you must record the information specified in paragraphs 
(g)(4)(i)(A) through (C) of this section.
    (A) A description of the maintenance activity resulting in elevated 
mercury concentration;
    (B) The time the maintenance activity was initiated and completed; 
and
    (C) A detailed explanation how all the applicable requirements of 
Table 1 to this subpart were met during the maintenance activity.
    (ii) If you determine that the cause of the elevated mercury 
concentration is not an open electrolyzer, decomposer, or other 
maintenance activity, you must follow the procedures specified in 
paragraphs (g)(4)(ii)(A) and (B) of this section until the mercury 
concentration falls below the action level. You must also keep all the 
associated records for these procedures as specified in Table 9 to this 
subpart.
    (A) Within 1 hour of the time the action level was exceeded, you 
must conduct each inspection specified in Table 2 to this subpart, with 
the exception of the cell room floor and the pillars and beam 
inspections. You must correct any problem identified during these 
inspections in accordance with the requirements in Table 2 and 3 to 
this subpart.
    (B) If the Table 2 inspections and subsequent corrective actions do 
not reduce the mercury concentration below the action level, you must 
inspect all decomposers, hydrogen system piping up to the hydrogen 
header, and other potential locations of mercury vapor leaks using a 
technique specified in Table 6 to this subpart. If a mercury vapor leak 
is identified, you must take the appropriate action specified in Table 
3 to this subpart.

Operation and Maintenance Requirements


Sec.  63.8222  What are my operation and maintenance requirements?

    As required by Sec.  63.6(e)(1)(i), you must always operate and 
maintain your affected source(s), including air pollution control and 
monitoring equipment, in a manner consistent with safety and good air 
pollution control practices for minimizing emissions.

General Compliance Requirements


Sec.  63.8226  What are my general requirements for complying with this 
subpart?

    (a) You must be in compliance with the applicable emission 
limitations for by-product hydrogen streams, end box ventilation system 
vents, and mercury thermal recovery unit vents in Sec.  63.8190 at all 
times, except during periods of startup, shutdown, and malfunction. You 
must be in compliance with the applicable work practice standards in 
Sec.  63.8192 at all times, except during periods of startup, shutdown, 
and malfunction.
    (b) You must develop and implement a written startup, shutdown, and 
malfunction plan (SSMP) according to the provisions in Sec.  
63.6(e)(3).

Initial Compliance Requirements


Sec.  63.8230  By what date must I conduct performance tests or other 
initial compliance demonstrations?

    (a) You must conduct a performance test no later than the 
compliance date that is specified in Sec.  63.8186 for your affected 
source to demonstrate initial compliance with the applicable emission 
limit in Sec.  63.8190(a)(2) for by-product hydrogen streams and end 
box ventilation system vents and the

[[Page 70931]]

applicable emission limit in Sec.  63.8190(a)(3) for mercury thermal 
recovery unit vents.
    (b) For the applicable work practice standards in Sec.  63.8192, 
you must demonstrate initial compliance within 30 calendar days after 
the compliance date that is specified for your affected source in Sec.  
63.8186.


Sec.  63.8232  What test methods and other procedures must I use to 
demonstrate initial compliance with the emission limits?

    You must conduct a performance test for each by-product hydrogen 
stream, end box ventilation system vent, and mercury thermal recovery 
unit vent according to the requirements in Sec.  63.7(e)(1) and the 
conditions detailed in paragraphs (a) through (d) of this section.
    (a) You may not conduct performance tests during periods of 
startup, shutdown, or malfunction, as specified in Sec.  63.7(e)(1).
    (b) For each performance test, you must develop a site-specific 
test plan in accordance with Sec.  63.7(c)(2).
    (c) You must conduct at least three test runs to comprise a 
performance test, as specified in Sec.  63.7(e)(3) and in either 
paragraph (c)(1) or (2) of this section.
    (1) The sampling time and sampling volume for each run must be at 
least 2 hours and 1.70 dry standard cubic meters (dscm). Mercury 
results below the analytical laboratory's detection limit must be 
reported using the reported analytical detection limit to calculate the 
sample concentration value and, in turn, the emission rate in the units 
of the standard; or
    (2) The sampling time for each test run must be at least 2 hours 
and the mercury concentration in each field sample analyzed must be at 
least two times the reported analytical detection limit.
    (d) You must use the test methods specified in paragraphs (d)(1) 
through (4) of this section and the applicable test methods in 
paragraphs (d)(5) through (7) of this section.
    (1) Method 1 or 1A in appendix A of 40 CFR part 60 to determine the 
sampling port locations and the location and required number of 
sampling traverse points.
    (2) Method 2, 2A, 2C, or 2D in appendix A of 40 CFR part 60 to 
determine the stack gas velocity and volumetric flow rate.
    (3) Method 3, 3A, or 3B in appendix A of 40 CFR part 60 to 
determine the stack gas molecular weight.
    (4) Method 4 in appendix A of 40 CFR part 60 to determine the stack 
gas moisture content.
    (5) For each by-product hydrogen stream, Method 102 in appendix A 
of 40 CFR part 61 to measure the mercury emission rate after the last 
control device.
    (6) For each end box ventilation system vent, Method 101 or 101A in 
appendix A of 40 CFR part 61 to measure the mercury emission rate after 
the last control device.
    (7) For each mercury thermal recovery unit vent, Method 101 or 101A 
in appendix A of 40 CFR part 61 to measure the mercury emission rate 
after the last control device.
    (e) During each test run for a by-product hydrogen stream and each 
test run for an end box ventilation system vent, you must continuously 
measure the electric current through the operating mercury cells and 
record a measurement at least once every 15 minutes.
    (f) If the final control device is not a nonregenerable carbon 
adsorber and if you are demonstrating compliance using periodic 
monitoring under Sec.  63.8240(b), you must continuously monitor the 
parameters listed in paragraph (f)(1) of this section and establish 
your maximum or minimum monitoring value (as appropriate for your 
control device) using the requirements in paragraph (f)(2) of this 
section.
    (1) During the performance test specified in paragraphs (a) through 
(d) of this section, you must continuously monitor the control device 
parameters in paragraphs (f)(1)(i) through (vii) of this section and 
record a measurement at least once every 15 minutes.
    (i) The exit gas temperature from uncontrolled streams;
    (ii) The outlet temperature of the gas stream for the final (i.e., 
the farthest downstream) cooling system when no control devices other 
than coolers or demisters are used;
    (iii) The outlet temperature of the gas stream from the final 
cooling system when the cooling system is followed by a molecular sieve 
or regenerative carbon adsorber;
    (iv) Outlet concentration of available chlorine, pH, liquid flow 
rate, and inlet gas temperature of chlorinated brine scrubbers and 
hypochlorite scrubbers;
    (v) The liquid flow rate and exit gas temperature for water 
scrubbers;
    (vi) The inlet gas temperature of regenerative carbon adsorption 
systems; and
    (vii) The temperature during the heating phase of the regeneration 
cycle for carbon adsorbers or molecular sieves.
    (2) To establish a maximum monitoring value or minimum monitoring 
value, as appropriate for your final control device, you must average 
the recorded parameters in paragraphs (f)(1)(i) through (vi) of this 
section over the test period. If your final control device is a 
regenerative carbon adsorber, you must use the highest temperature 
reading measured in paragraph (f)(1)(vii) as the reference temperature 
in Sec.  63.8244(b)(2)(v).


Sec.  63.8234  What equations and procedures must I use for the initial 
compliance demonstration?

    (a) By-product hydrogen streams and end box ventilation system 
vents. You must determine the total grams of mercury per Megagram of 
chlorine production (g Hg/Mg Cl2) of chlorine produced from 
all by-product hydrogen streams and all end box ventilation system 
vents, if applicable, at a mercury cell chlor-alkali production 
facility, and you must follow the procedures in paragraphs (a)(1) 
through (6) of this section.
    (1) Determine the mercury emission rate for each test run in grams 
per day for each by-product hydrogen stream and for each end box 
ventilation system vent, if applicable, from Method 101, 101A, or 102 
(40 CFR part 61, appendix A).
    (2) Calculate the average measured electric current through the 
operating mercury cells during each test run for each by-product 
hydrogen stream and for each end box ventilation system vent, if 
applicable, using Equation 1 of this section as follows:
[GRAPHIC] [TIFF OMITTED] TR19DE03.000


Where:
CLavg, run = Average measured cell line current load during 
the test run, amperes;
CLi, run = Individual cell line current load measurement 
(i.e., 15 minute reading) during the test run, amperes; and
n = Number of cell line current load measurements taken over the 
duration of the test run.

    (3) Calculate the amount of chlorine produced during each test run 
for each by-product hydrogen stream and for each end box ventilation 
system vent, if applicable, using Equation 2 of this section as 
follows:

[[Page 70932]]

[GRAPHIC] [TIFF OMITTED] TR19DE03.001


Where:
PCl2,run = Amount of chlorine produced during the 
test run, megagrams chlorine (Mg Cl2);
1.3 x 10 -6 = Theoretical chlorine production rate factor, 
Mg Cl2 per hour per ampere per cell;
CLavg,run = Average measured cell line current load during 
test run, amperes, calculated using Equation 1 of this section;
ncell,run = Number of cells on-line during the test run; and
trun = Duration of test run, hours.

    (4) Calculate the mercury emission rate in grams of mercury per 
megagram of chlorine produced for each test run for each by-product 
hydrogen stream and for each end box ventilation system vent, if 
applicable, using Equation 3 of this section as follows:
[GRAPHIC] [TIFF OMITTED] TR19DE03.002


Where:
EHg,run = Mercury emission rate for the test run, g Hg/Mg 
Cl2;
Rrun = Measured mercury emission rate for the test run from 
paragraph (a)(1) of this section, grams Hg per day;
trun = Duration of test run, hours;
24 = Conversion factor, hours per day; and
PCl2,run = Amount of chlorine produced during the 
test run, calculated using Equation 2 of this section, Mg 
Cl2.

    (5) Calculate the average mercury emission rate for each by-product 
hydrogen stream and for each end box ventilation system vent, if 
applicable, using Equation 4 of this section as follows:
[GRAPHIC] [TIFF OMITTED] TR19DE03.003


Where:
EHg,avg = Average mercury emission rate for the by-product 
hydrogen stream or the end box ventilation system vent, if applicable, 
g Hg/Mg Cl2;
EHg,run = Mercury emission rate for each test run for the 
by-product hydrogen stream or the end box ventilation system vent, if 
applicable, g Hg/Mg Cl2, calculated using Equation 3 of this 
section; and
n = Number of test runs conducted for the by-product hydrogen stream or 
the end box ventilation system vent, if applicable.

    (6) Calculate the total mercury emission rate from all by-product 
hydrogen streams and all end box ventilation system vents, if 
applicable, at the mercury cell chlor-alkali production facility using 
Equation 5 of this section as follows:
[GRAPHIC] [TIFF OMITTED] TR19DE03.004


Where:
EHg,H2EB = Total mercury emission rate from all 
by-product hydrogen streams and all end box ventilation system vents, 
if applicable, at the affected source, g Hg/Mg Cl2;
EHg,avg = Average mercury emission rate for each by-product 
hydrogen stream and each end box ventilation system vent, if 
applicable, g Hg/Mg Cl2, determined using Equation 4 of this 
section; and
n = Total number of by-product hydrogen streams and end box ventilation 
system vents at the affected source.

    (b) Mercury thermal recovery vents. You must determine the 
milligrams of mercury per dscm exhaust discharged from mercury thermal 
recovery unit vents, using the procedures in paragraphs (b)(1) and (2) 
of this section.
    (1) Calculate the concentration of mercury in milligrams of mercury 
per dscm of exhaust for each test run for each mercury thermal recovery 
unit vent using Equation 6 of this section as follows:
[GRAPHIC] [TIFF OMITTED] TR19DE03.005


Where:
CHg,run = Mercury concentration for the test run, milligrams 
of mercury per dry standard cubic meter of exhaust;
mHg = Mass of mercury in test run sample, from Method 101, 
101A, or 102, micrograms;
10-3 = Conversion factor, milligrams per microgram; and
Vm(std) = Dry gas sample volume at standard conditions, from 
Method 101, 101A, or 102, dry standard cubic meters.

    (2) Calculate the average concentration of mercury in each mercury 
thermal recovery unit vent exhaust using Equation 7 of this section as 
follows:
[GRAPHIC] [TIFF OMITTED] TR19DE03.006


Where:
CHg,avg = Average mercury concentration for the mercury 
thermal recovery unit vent, milligrams of mercury per dry standard 
cubic meter exhaust;
CHg,run = Mercury concentration for each test run, 
milligrams of mercury per dry standard cubic meter of exhaust, 
calculated using Equation 6 of this section; and
n = Number of test runs conducted for the mercury thermal recovery unit 
vent.


Sec.  63.8236  How do I demonstrate initial compliance with the 
emission limitations and work practice standards?

    (a) For each mercury cell chlor-alkali production facility, you 
have demonstrated initial compliance with the applicable emission limit 
for by-product hydrogen streams and end box ventilation system vents in 
Sec.  63.8190(a)(2) if you comply with paragraphs (a)(1) and (2) of 
this section:
    (1) Total mercury emission rate from all by-product hydrogen 
streams and all end box ventilation system vents, if applicable, at the 
affected source, determined according to Sec. Sec.  63.8232 and 
63.8234(a), did not exceed the applicable emission limit in Sec.  
63.8190(a)(2)(i) or (ii); and
    (2) If you have chosen the periodic monitoring option specified in 
Sec.  63.8240(b) and your final control device is not a nonregenerable 
carbon adsorber, you have established a parameter value according to 
Sec.  63.8232(f)(2).
    (b) For each mercury recovery facility, you have demonstrated 
initial compliance with the applicable emission limit for mercury 
thermal recovery unit vents in Sec.  63.8190(a)(3) if you comply with 
paragraphs (b)(1) and (2) of this section.
    (1) Mercury concentration in each mercury thermal recovery unit 
vent exhaust, determined according to Sec. Sec.  63.8232 and 
63.8234(b), did not exceed the applicable emission limit in Sec.  
63.8190(a)(3)(i) or (ii); and
    (2) If you have chosen the periodic monitoring option in Sec.  
63.8240(b) and have a final control device that is not a nonregenerable 
carbon adsorber, you

[[Page 70933]]

have established a maximum or minimum monitoring value, as appropriate 
for your control device according to Sec.  63.8232(f)(2).
    (c) For each affected source, you have demonstrated initial 
compliance with the applicable work practice standards in Sec.  63.8192 
if you comply with paragraphs (c)(1) through (7) of this section.
    (1) You certify in your Notification of Compliance Status that you 
are operating according to the work practice standards in Sec.  
63.8192(a) through (d).
    (2) You choose the continuous cell room monitoring program option, 
you certify in your Notification of Compliance Status that you are 
operating according to the continuous cell room monitoring program 
under Sec.  63.8192(g) and you have established your action level 
according to Sec.  63.8192(g)(2).
    (3) You certify in your Notification of Compliance Status that you 
are operating according to your washdown plan.
    (4) You have submitted your washdown plan as part of your 
Notification of Compliance Status.
    (5) You have submitted your continuous cell room monitoring plan, 
if applicable, as part of your Notification of Compliance Status.
    (6) You have submitted your floor-level cell room monitoring plan, 
if applicable, as part of your Notification of Compliance Status.
    (7) You have submitted records of the mass of virgin mercury added 
to cells for the 5 years preceding the applicable compliance date for 
your affected source as a part of the Notification of Compliance 
Status.
    (d) You must submit the Notification of Compliance Status 
containing the results of the initial compliance demonstration 
according to the requirements in Sec.  63.8252(e).

Continuous Compliance Requirements


Sec.  63.8240  What are my monitoring requirements?

    For each by-product hydrogen stream, each end box ventilation 
system vent, and each mercury thermal recovery unit vent, you must 
monitor the mercury emissions using the procedures in paragraph (a) or 
(b) of this section.
    (a) You must continuously monitor the mercury concentration using a 
mercury continuous emissions monitor according to the requirements in 
Sec. Sec.  63.8242(a) and 63.8244(a); or
    (b) You must periodically monitor the mercury emissions according 
to the requirements in Sec. Sec.  63.8242(b) and 63.8244(b).


Sec.  63.8242  What are the installation, operation, and maintenance 
requirements for my continuous monitoring systems?

    (a) If you choose the continuous mercury monitoring option under 
Sec.  63.8240(a), you must install, operate, and maintain each mercury 
continuous emissions monitor according to paragraphs (a)(1) through (5) 
of this section.
    (1) Each mercury continuous emissions monitor must sample, analyze, 
and record the concentration of mercury at least once every 15 minutes.
    (2) Each mercury continuous emissions monitor analyzer must have a 
detector with the capability to detect a mercury concentration at or 
below 0.5 times the mercury concentration level measured during the 
performance test conducted according to Sec.  63.8232.
    (3) In lieu of a promulgated performance specification as required 
in Sec.  63.8(a)(2), you must develop a site-specific monitoring plan 
that addresses the elements in paragraphs (a)(3)(i) through (vi) of 
this section.
    (i) Installation and measurement location downstream of the final 
control device for each by-product hydrogen stream, end box ventilation 
system vent, and mercury thermal recovery unit vent.
    (ii) Performance and equipment specifications for the sample 
interface, the pollutant concentration analyzer, and the data 
collection and reduction system.
    (iii) Performance evaluation procedures and acceptance criteria 
(i.e., calibrations).
    (iv) Ongoing operation and maintenance procedures according to the 
requirements of Sec.  63.8(c)(1), (3), and (4)(ii).
    (v) Ongoing data quality assurance procedures according to the 
requirements of Sec.  63.8(d).
    (vi) Ongoing recordkeeping and reporting procedures in accordance 
with the general requirements of Sec.  63.10(c), (e)(1), and (e)(2)(i).
    (4) You must conduct a performance evaluation of each mercury 
continuous emissions monitor according to your site-specific monitoring 
plan.
    (5) You must operate and maintain each mercury continuous emissions 
monitor in continuous operation according to the site-specific 
monitoring plan.
    (b) If you choose the periodic monitoring option and your final 
control device is not a nonregenerable carbon adsorber, you must 
install, operate, and maintain a continuous parameter monitoring system 
(CPMS) for each parameter specified in Sec.  63.8232(f)(1), according 
to Sec.  63.8(c).


Sec.  63.8243  What equations and procedures must I use to demonstrate 
continuous compliance?

    (a) By-product hydrogen streams and end box ventilation system 
vents. For each consecutive 52-week period, you must determine the g 
Hg/Mg Cl2 produced from all by-product hydrogen streams and 
all end box ventilation system vents, if applicable, at a mercury cell 
chlor-alkali production facility using the procedures in paragraphs 
(a)(1) through (3) of this section. You must begin collecting data on 
the compliance date that is specified in Sec.  63.8186 for your 
affected source and calculate your first 52-week average mercury 
emission rate at the end of the 52nd week after the compliance date.
    (1) Each week, you must determine the weekly mercury emission rate 
in grams per week for each by-product hydrogen stream and for each end 
box ventilation system vent, if applicable, using one of the monitoring 
options in paragraph (a)(1)(i) or (ii) of this section.
    (i) Continuous mercury monitoring according to Sec. Sec.  63.8242 
and 63.8244(a).
    (ii) Periodic monitoring according to Sec.  63.8244(b).
    (2) Each week, you must determine the chlorine production and keep 
records of the production rate as required under Sec.  63.8256(b)(6).
    (3) Beginning 52 weeks after the compliance date specified in Sec.  
63.8186 for your affected source, you must calculate the 52-week 
average mercury emission rate from all by-product hydrogen steam and 
all end box ventilation system vents, if applicable, using Equation 1 
of this section as follows:
[GRAPHIC] [TIFF OMITTED] TR19DE03.007


Where:
EHg = 52-week average mercury emission rate for 
weeki, g Hg/Mg Cl2;
Rweek, i = Mercury emission rate for weeki from 
paragraph (a)(1) of this section, g Hg per week;
PCl2, weeki = Amount of chlorine produced during 
weeki, from paragraph (a)(2) of this section, Mg 
Cl2 per week.

    (b) Mercury thermal recovery units. If you choose the continuous 
monitoring option in Sec.  63.8240(a), you must demonstrate continuous 
compliance using paragraph (b)(1) of this section. If you choose the 
periodic monitoring option in Sec.  63.8240(b), you must demonstrate 
continuous compliance using paragraph (b)(2) of this section.

[[Page 70934]]

    (1) You must calculate the daily average mercury concentration 
using Equation 2 of this section as follows:
[GRAPHIC] [TIFF OMITTED] TR19DE03.008


Where:
CHg, dailyavg = Average mercury concentration for the 
operating day, milligrams per dry standard cubic meter;
CHg,i = Concentration of mercury measured at the interval i 
(i.e., 15 minute reading) using a mercury continuous emission monitor, 
milligrams per dry standard cubic meter; and
n = Number of concentration measurements taken during the operating 
day.

    (2) You must calculate the daily average mercury concentration 
using the procedures in Sec.  63.8234(b).


Sec.  63.8244  How do I monitor and collect data to demonstrate 
continuous compliance?

    (a) Continuous monitoring option. You must monitor mercury 
concentration according to Sec.  63.8242(a) at all times that the 
affected source is operating with the exception of paragraphs (a)(1) 
and (2) of this section.
    (1) Except for monitor malfunctions, associated repairs, and 
required quality assurance or control activities (including, as 
applicable, calibration checks and required zero and span adjustments), 
you must monitor mercury emissions continuously (or collect data at all 
required intervals) at all times that the affected source is operating. 
A monitoring malfunction is any sudden, infrequent, not reasonably 
preventable failure of the monitoring to provide valid data. Monitoring 
failures that are caused in part by poor maintenance or careless 
operation are not malfunctions.
    (2) You may not use data recorded during monitoring malfunctions, 
associated repairs, and required quality assurance or control 
activities in data averages and calculations used to report emission or 
operating levels or to fulfill a minimum data availability requirement, 
if applicable. You must use all the data collected during all other 
periods in assessing compliance.
    (b) Periodic monitoring option. If you choose the periodic 
monitoring option under Sec.  63.8240(b), you must monitor according to 
the procedures in paragraph (b)(1) or (2) of this section.
    (1) If your final control device is a nonregenerable carbon 
adsorber, then you must conduct at least three test runs per week 
meeting the criteria specified in Sec.  63.8232(c)(1) and (2) to 
measure mercury emissions using the test methods specified in Sec.  
63.8232(d). Alternatively, you may use any other method that has been 
validated using the applicable procedures in Method 301, 40 CFR part 
63, appendix A.
    (2) If your final control device is anything other than a 
nonregenerable carbon adsorber, you must monitor according to the 
requirements of paragraphs (b)(2)(i) through (v) of this section.
    (i) You must conduct at least three test runs per week meeting the 
criteria specified in Sec.  63.8232(c)(1) and (2) to measure mercury 
emissions using the test methods specified in Sec.  63.8232(d). 
Alternatively, you may use any other method that has been validated 
using the applicable procedures in Method 301, 40 CFR part 63, appendix 
A.
    (ii) Except as specified in paragraph (b)(2)(iii) of this section, 
you must continuously collect data at least once every 15 minutes using 
a CPMS installed and operated according to Sec.  63.8242(b) and record 
each 1-hour average from all measured data values during each 1-hour 
period for the applicable parameter identified in Sec.  63.8232(f)(1) 
using the methods specified in Sec.  63.8244(a).
    (iii) As appropriate, you must continuously monitor the temperature 
specified in Sec.  63.8232(f)(1)(vii) during each heating phase of the 
regeneration cycle of your carbon adsorber.
    (iv) If the hourly average monitoring value of any applicable 
parameter recorded under paragraph (b)(2)(ii) of this section is below 
the minimum monitoring value or above the maximum monitoring value of 
that same parameter established under Sec.  63.8232(f)(2) for 24 
consecutive hours, your monitoring value is out of range and you must 
take corrective action as soon as practicable. The hourly average 
monitoring value must be above the minimum monitoring value or below 
the maximum monitoring value as appropriate for that parameter, within 
48 hours of the period that the monitoring value is out of range.
    (v) If your final control device is a regenerative carbon adsorber, 
when the maximum hourly value of the temperature measured according to 
paragraph (b)(2)(iii) of this section is below the reference 
temperature determined according to Sec.  63.8232(f)(2) for three 
consecutive regeneration cycles, your monitoring value is out of range 
and you must take corrective action as soon as practicable. During the 
first regeneration cycle following the period that your monitoring 
value is out of range, the maximum hourly value must be above the 
reference temperature recorded according to Sec.  63.8232(f)(2).


Sec.  63.8246  How do I demonstrate continuous compliance with the 
emission limitations and work practice standards?

    (a) By-product hydrogen streams and end box ventilation system 
vents. (1) For all by-product hydrogen streams and all end box 
ventilation system vents, if applicable, you must demonstrate 
continuous compliance with the applicable mercury emission limit by 
reducing the mercury emissions data to 52-week averages using Equation 
1 of Sec.  63.8243 and maintaining the 52-week average mercury 
emissions no higher than the applicable mercury emissions limit in 
Sec.  63.8190(a)(2). To obtain the data to calculate these 52-week 
averages, you must monitor in accordance with paragraph (a)(1)(i) or 
(ii) of this section.
    (i) Continuous monitoring option. You must collect mercury 
emissions data according to Sec.  63.8244(a), representing at least 75 
percent of the 15-minute periods in each operating day of the 52-week 
compliance period (with data recorded during monitoring malfunctions, 
associated repairs, and required quality assurance or control 
activities not counting toward the 75 percent requirement);
    (ii) Periodic monitoring option. You must conduct at least three 
test runs per week to collect mercury emissions samples according to 
Sec.  63.8244(b)(1) and (2)(i) and, if your final control device is not 
a nonregenerable carbon adsorber, you must collect data for monitoring 
values according to Sec.  63.8244(b)(2)(ii) through (v).
    (2) You must maintain records of mercury emissions and 52-week 
average values, as required in Sec.  63.8256(b)(3) and (4). If your 
final control device is not a nonregenerable carbon adsorber, you must 
maintain records according to Sec.  63.8256(d).
    (b) Mercury thermal recovery unit vents. (1) For each mercury 
thermal recovery unit vent, you must demonstrate continuous compliance 
with the applicable emission limit specified in Sec.  63.8190(a)(3) by 
maintaining the outlet mercury hourly-average concentration no higher 
than the applicable limit. To determine the outlet mercury 
concentration, you must monitor according to paragraph (b)(1)(i) or 
(ii) of this section.
    (i) Continuous monitoring option. You must collect mercury 
concentration data according to Sec.  63.8244(a), representing at least 
75 percent of the 15-minute periods in the operating day (with data

[[Page 70935]]

recorded during monitoring malfunctions, associated repairs, and 
required quality assurance or control activities not counting toward 
the 75 percent requirement).
    (ii) Periodic monitoring option. You must conduct at least three 
test runs per week to collect mercury emissions samples according to 
Sec.  63.8244(b)(1) and (2)(i) and, if your final control device is not 
a nonregenerable carbon adsorber, you must collect data for monitoring 
values according to Sec.  63.8244(b)(2)(ii) through (v).
    (2) You must maintain records of mercury emissions and daily 
average values as required in Sec.  63.8256(b)(3). If your final 
control device is not a nonregenerable carbon adsorber, you must 
maintain records according to Sec.  63.8256(d).
    (c) You must demonstrate continuous compliance with the applicable 
work practice standards in Sec.  63.8192 by maintaining records in 
accordance with Sec.  63.8256(c).


Sec.  63.8248  What other requirements must I meet?

    (a) Deviations. The instances specified in paragraphs (a)(1) 
through (4) of this section are deviations and must be reported 
according to the requirements in Sec.  63.8254.
    (1) You must report each instance in which you did not meet each 
emission limitation in Sec.  63.8190 that applies to you. This includes 
periods of startup, shutdown, and malfunction.
    (2) You must report each instance in which you did not meet each 
work practice standard in Sec.  63.8192 that applies to you. This 
includes periods of startup, shutdown, and malfunction.
    (3) You must report each instance in which the corrective actions 
taken according to Sec.  63.8244(b)(2)(iv) did not result in average 
monitoring values being within range within 48 hours of the period that 
the monitoring value is out of range.
    (4) You must report each instance in which the corrective action 
taken according to Sec.  63.8244(b)(2)(v) did not result in the maximum 
hourly temperature being above the reference temperature during the 
first regeneration cycle following the period that the monitoring value 
was out of range.
    (b) Startups, shutdowns, and malfunctions. During periods of 
startup, shutdown, and malfunction, you must operate in accordance with 
your startup, shutdown, and malfunction plan that satisfies the 
requirements in Sec.  63.6(e) and as required in Sec.  63.8226(b).
    (1) Consistent with Sec. Sec.  63.6(e) and 63.7(e)(1), deviations 
that occur during a period of startup, shutdown, or malfunction are not 
violations if you demonstrate to the Administrator's satisfaction that 
you have an adequate startup, shutdown, or malfunction plan that 
satisfies the requirements of Sec.  63.6(e), and you have complied with 
the startup, shutdown, and malfunction plan.
    (2) The Administrator will determine whether deviations that occur 
during a period of startup, shutdown, or malfunction are violations, 
according to the provisions in Sec.  63.6(e).
    (3) By-passing the control device for maintenance activities is not 
considered a startup, shutdown, or malfunction event.

Notification, Reports, and Records


Sec.  63.8252  What notifications must I submit and when?

    (a) You must submit all of the notifications in Sec. Sec.  63.7(b) 
and (c), 63.8(e) and (f) and 63.9(b) through (h) that apply to you by 
the dates specified.
    (b) As specified in Sec.  63.9(b)(2), if you start up your affected 
source before December 19, 2003, you must submit your initial 
notification not later than April 19, 2004.
    (c) As specified in Sec.  63.9(b)(3), if you start up your new or 
reconstructed mercury recovery facility on or after December 19, 2003, 
you must submit your initial notification not later than 120 days after 
you become subject to this subpart.
    (d) For each performance test that you are required to conduct for 
by-product hydrogen streams and end box ventilation system vents and 
for mercury thermal recovery unit vents, you must submit a notification 
of intent to conduct a performance test at least 60 calendar days 
before the performance test is scheduled to begin as required in Sec.  
7(b)(1).
    (e) You must submit a Notification of Compliance Status according 
to paragraphs (e)(1) and (2) of this section.
    (1) For each initial compliance demonstration that does not include 
a performance test, you must submit the Notification of Compliance 
Status before the close of business on the 30th calendar day following 
the completion of the initial compliance demonstration. The 
Notification of Compliance Status must contain the items in paragraphs 
(e)(1)(i) through (iv) of this section:
    (i) If you choose not to implement a cell room monitoring program 
according to Sec.  63.8192(g), a certification that you are operating 
according to the applicable work practice standards in Sec.  63.8192(a) 
through (d) and your floor-level mercury vapor measurement plan 
required by Sec.  63.8192(d).
    (ii) The washdown plan, and you must certify that you are operating 
according to the washdown plan specified in Sec.  63.8192(f).
    (iii) The mass of virgin mercury added to cells for the 5 years 
preceding the compliance date.
    (iv) If you choose to implement a cell room monitoring program 
according to Sec.  63.8192(g), your cell room monitoring plan.
    (2) For each initial compliance demonstration that does include a 
performance test, you must submit the Notification of Compliance 
Status, including the performance test results, before the close of 
business on the 60th calendar day following the completion of the 
performance test according to Sec.  63.10(d)(2). The Notification of 
Compliance Status must contain the information in Sec.  
63.9(h)(2)(ii)(A) through (G). The site-specific monitoring plan 
required in Sec.  63.8242(a)(3) must also be submitted.


Sec.  63.8254  What reports must I submit and when?

    (a) Compliance report due dates. You must submit a semiannual 
compliance report to your permitting authority according to the 
requirements in paragraphs (a)(1) through (4) of this section.
    (1) The first compliance report must cover the period beginning on 
the compliance date that is specified for your affected source in Sec.  
63.8186 and ending on June 30 or December 31, whichever date comes 
first after the compliance date that is specified for your affected 
source in Sec.  63.8186.
    (2) The first compliance report must be postmarked or delivered no 
later than July 31 or January 31, whichever date comes first after your 
first compliance reporting period.
    (3) Each subsequent compliance report must cover the semiannual 
reporting period from January 1 through June 30 or the semiannual 
reporting period from July 1 through December 31.
    (4) Each subsequent compliance report must be postmarked or 
delivered no later than July 31 or January 31, whichever date comes 
first after the end of the semiannual reporting period.
    (b) Compliance report contents. Each compliance report must contain 
the information in paragraphs (b)(1) through (3) of this section, and 
as applicable, paragraphs (b)(4) through (12) of this section.
    (1) Company name and address.
    (2) Statement by a responsible official, with that official's name, 
title, and signature, certifying the truth, accuracy, and completeness 
of the report.

[[Page 70936]]

    (3) Date of report and beginning and ending dates of the reporting 
period.
    (4) If you had a startup, shutdown or malfunction during the 
reporting period and you took actions consistent with your startup, 
shutdown, and malfunction plan, the compliance report must include the 
information in Sec.  63.10(d)(5)(i).
    (5) If there were no deviations from the continuous compliance 
requirements in Sec.  63.8246 that apply to you, a statement that there 
were no deviations from the emission limitations, work practice 
standards, and operation and maintenance standards during the reporting 
period.
    (6) If there were no periods during which the mercury continuous 
emission monitor or CPMS (if applicable) were out-of-control as 
specified in Sec.  63.8(c)(7), a statement that there were no periods 
during the which the mercury continuous emissions monitor or CPMS (if 
applicable) were out-of-control during the reporting period.
    (7) For each deviation from the requirements for work practice 
standards in Tables 1 through 4 to this subpart that occurs at an 
affected source (including deviations where the response intervals were 
not adhered to as described in Sec.  63.8192(b)), the compliance report 
must contain the information in paragraphs (b)(1) through (4) of this 
section and the information in paragraphs (b)(7)(i) and (ii) of this 
section. This includes periods of startup, shutdown, and malfunction.
    (i) The total operating time of each affected source during the 
reporting period.
    (ii) Information on the number, duration, and cause of deviations 
(including unknown cause, if applicable), as applicable, and the 
corrective action taken.
    (8) For each deviation from an emission limitation occurring at an 
affected source where you are using a mercury continuous emission 
monitor, according to the site-specific monitoring plan required in 
Sec.  63.8242(a)(3), to comply with the emission limitation in this 
subpart, you must include the information in paragraphs (b)(1) through 
(4) of this section and the information in paragraphs (b)(8)(i) through 
(xii) of this section. This includes periods of startup, shutdown, and 
malfunction.
    (i) The date and time that each malfunction started and stopped.
    (ii) The date and time of each instance in which a continuous 
monitoring system was inoperative, except for zero (low-level) and 
high-level checks.
    (iii) The date, time, and duration of each instance in which a 
continuous monitoring system was out-of-control, including the 
information in Sec.  63.8(c)(8).
    (iv) The date and time that each deviation started and stopped, and 
whether each deviation occurred during a period of startup, shutdown, 
or malfunction or during another period.
    (v) A summary of the total duration of the deviation during the 
reporting period and the total duration as a percent of the total 
source operating time during that reporting period.
    (vi) A breakdown of the total duration of the deviations during the 
reporting period including those that are due to startup, shutdown, 
control equipment problems, process problems, other known causes, and 
other unknown causes.
    (vii) A summary of the total duration of continuous monitoring 
system downtime during the reporting period and the total duration of 
monitoring system downtime as a percent of the total source operating 
time during the reporting period.
    (viii) An identification of each hazardous air pollutant that was 
monitored at the affected source.
    (ix) A brief description of the process units.
    (x) A brief description of the continuous monitoring system.
    (xi) The date of the latest continuous monitoring system 
certification or audit.
    (xii) A description of any changes in monitoring system, processes, 
or controls since the last reporting period.
    (9) For each deviation from an operation and maintenance standard 
occurring at an affected source where you are using the periodic 
monitoring option specified in Sec.  63.8240(b) and your final control 
device is not a nonregenerable carbon adsorber, the compliance report 
must include the information in paragraphs (b)(1) through (4) of this 
section and the information in paragraphs (b)(9)(i) through (x) of this 
section. This includes periods of startups, shutdowns and malfunctions.
    (i) The total operating time of each affected source during the 
reporting period.
    (ii) Information on the number, duration, and cause of deviations 
(including unknown cause, if applicable), as applicable, whether the 
deviation occurred during a period of startup, shutdown, or 
malfunction, or other period, and the corrective action taken.
    (iii) The date and time of each instance in which a CPMS was 
inoperative, except for zero (low-level) and high-level checks.
    (iv) The date, time, and duration of each instance in which a CPMS 
was out-of-control, including the information specified in Sec.  
63.8(c)(8).
    (v) A summary of the total duration of the deviation during the 
reporting period and the total duration as a percent of the total 
source operating time during that reporting period.
    (vi) A breakdown of the total duration of the deviations during the 
reporting period including those that are due to startup, shutdown, 
control equipment problems, process problems, other known causes, and 
other unknown causes.
    (vii) A summary of the total duration of continuous monitoring 
system downtime during the reporting period and the total duration of 
monitoring system downtime as a percent of the total source operating 
time during the reporting period.
    (viii) A brief description of the CPMS.
    (ix) The date of the latest CPMS certification or audit.
    (x) A description of any changes in monitoring system, processes, 
or controls since the last reporting period.
    (10) The compliance report must contain the mass of virgin mercury 
added to cells for the reporting period.
    (11) The compliance report must contain each instance in which 
corrective actions taken under Sec.  63.8244(b)(2)(iv) did not result 
in average monitoring values being within range within 48 hours of the 
period that the monitoring value is out of range.
    (12) The compliance report must contain each instance in which 
corrective action taken according to Sec.  63.8244(b)(2)(v) did not 
result in the maximum hourly temperature being above the reference 
temperature during the first regeneration cycle following the period 
that the monitoring value was out of range.
    (c) Immediate startup, shutdown, and malfunction report. If you 
took an action during a startup, shutdown, or malfunction during the 
semiannual reporting period that was not consistent with your startup, 
shutdown, and malfunction plan required in Sec.  63.8226(b), and the 
source exceeded any applicable emission limitation in this subpart, you 
must submit an immediate startup, shutdown, and malfunction report 
according to the requirements in Sec.  63.10(d)(5)(ii).
    (d) Title V monitoring report. After your affected source has been 
issued a title V operating permit pursuant to 40 CFR part 70 or 40 CFR 
part 71, you must report all deviations from permit requirements and 
provide reports of any required monitoring in your semiannual 
monitoring report as required by 40 CFR 70.6(a)(3)(iii)(A) or 40 CFR 
71.6(a)(3)(iii)(A). If you submit a

[[Page 70937]]

semiannual compliance report for an affected source as required by this 
subpart as part of the semiannual monitoring report required by 40 CFR 
70.6(a)(3)(iii)(A) or 40 CFR 71.6(a)(3)(iii)(A), and the semiannual 
compliance report includes all information required by the 40 CFR part 
70 or 40 CFR part 71 semiannual monitoring report for the deviations 
that are reported in the semiannual compliance report, submission of 
the semiannual compliance report satisfies your obligation to report 
the same deviation information in the semiannual monitoring report. 
However, in such situations, the semiannual monitoring report must 
cross-reference the semiannual compliance report, and submission of a 
semiannual compliance report does not otherwise affect any obligation 
you may have to report deviations from permit requirements for an 
affected source to your permitting authority under 40 CFR part 70 or 40 
CFR part 71.


Sec.  63.8256  What records must I keep?

    (a) General records. You must keep the records in paragraphs (a)(1) 
and (2) of this section.
    (1) A copy of each notification and report that you submitted to 
comply with this subpart, including all documentation supporting any 
initial notification or Notification of Compliance Status that you 
submitted, according to the requirements in Sec.  63.10(b)(2)(xiv).
    (2) The records in Sec.  63.6(e)(3)(iii) through (v) related to 
startup, shutdown, and malfunction.
    (b) Records associated with the by-product hydrogen stream and end 
box ventilation system vent emission limitations and the mercury 
thermal recovery unit vent emission limitations. You must keep the 
records in paragraphs (b)(1) through (5) of this section related to the 
emission limitations in Sec.  63.8190(a)(2) through (3) and (b).
    (1) Records of performance tests as required in Sec.  
63.10(b)(2)(viii).
    (2) Records of the mercury emissions monitoring conducted during 
the performance tests.
    (3) Records of the continuous or periodic mercury emissions 
monitoring data.
    (4) Records of the 52-week rolling average mercury emissions.
    (5) Records associated with your site-specific monitoring plan 
required in Sec.  63.8242(a)(3) (i.e., results of inspections, 
calibrations, and validation checks of each mercury concentration 
continuous monitoring system (CMS)).
    (6) Records of chlorine production on a weekly basis.
    (c) Records associated with the work practice standards.
    (1) If you choose not to institute a cell room monitoring program 
according to Sec.  63.8192(g) of this subpart, you must keep the 
records specified in paragraphs (c)(1)(i) through (v) of this section.
    (i) Records specified in Table 9 to this subpart related to the 
work practice standards in Tables 1 through 4 of this subpart.
    (ii) Your current floor-level mercury vapor measurement plan.
    (iii) Records of the average value calculated from at least three 
measurements taken according to your floor-level mercury vapor 
measurement plan.
    (iv) Records indicated in Sec.  63.8192(d)(4)(i) for maintenance 
activities that cause the floor-level mercury concentration to exceed 
the action level.
    (v) Records of all inspections and corrective actions taken in 
response to a non-maintenance related situation in which the mercury 
vapor concentration exceeds the floor-level mercury concentration 
action level.
    (2) You must maintain a copy of your current washdown plan and 
records of when each washdown occurs.
    (3) You must maintain records of the mass of virgin mercury added 
to cells for each reporting period.
    (4) If you choose to institute a cell room monitoring program 
according to Sec.  63.8192(g) of this subpart, you must keep your 
current cell room monitoring plan and the records specified in 
paragraphs (c)(4)(i) through (v) of this section.
    (i) Records of the monitoring conducted in accordance with Sec.  
63.8192(g)(2)(i) to establish your action level, and records 
demonstrating the development of this action level.
    (ii) Records of the cell room mercury concentration monitoring data 
collected.
    (iii) Instances when the action level is exceeded.
    (iv) Records specified in Sec.  63.8192(g)(4)(i) for maintenance 
activities that cause the mercury vapor concentration to exceed the 
action level.
    (v) Records of all inspections and corrective actions taken in 
response to a non-maintenance related situation in which the mercury 
vapor concentration exceeds the action level.
    (d) Records associated with the periodic monitoring option if your 
final control device is not a nonregenerable carbon adsorber. You must 
keep the records in paragraph (d)(1) through (3) of this section.
    (1) Records of the CPMS data collected during the performance test 
as specified in Sec.  63.8232(f)(1).
    (2) Records documenting the development of the maximum monitoring 
value or minimum monitoring value, as appropriate, according to Sec.  
63.8232(f)(2).
    (3) Records of hourly average values of applicable parameters 
monitored as specified in Sec.  63.8244(b)(2)(ii) or (iii).


Sec.  63.8258  In what form and how long must I keep my records?

    (a) Your records must be in a form suitable and readily available 
for expeditious inspection and review, according to Sec.  63.10(b)(1).
    (b) As specified in Sec.  63.10(b)(1), you must keep each record 
for 5 years following the date of each occurrence, measurement, 
maintenance, corrective action, report, or record.
    (c) You must keep each record on site for at least 2 years after 
the date of each occurrence, measurement, maintenance, corrective 
action, report, or record, according to Sec.  63.10(b)(1). You can keep 
the records offsite for the remaining 3 years.

Other Requirements and Information


Sec.  63.8262  What parts of the General Provisions apply to me?

    Table 10 to this subpart shows which parts of the General 
Provisions in Sec. Sec.  63.1 through 63.13 apply to you.


Sec.  63.8264  Who implements and enforces this subpart?

    (a) This subpart can be implemented and enforced by us, the United 
States Environmental Protection Agency (U.S. EPA), or a delegated 
authority such as your State, local, or tribal agency. If the EPA 
Administrator has delegated authority to your State, local, or tribal 
agency, then that agency has the authority to implement and enforce 
this subpart. You should contact your EPA Regional Office to find out 
if this subpart is delegated to your State, local, or tribal agency.
    (b) In delegating implementation and enforcement authority of this 
subpart to a State, local, or tribal agency under subpart E of this 
part, the authorities contained in paragraph (c) of this section are 
retained by the EPA Administrator and are not transferred to the State, 
local, or tribal agency.
    (c) The authorities in paragraphs (c)(1) through (4) of this 
section will not be delegated to State, local, or tribal agencies.
    (1) Approval of alternatives under Sec.  63.6(g) to the non-opacity 
emission limitations in Sec.  63.8190 and work practice standards in 
Sec.  63.8192.

[[Page 70938]]

    (2) Approval of major alternatives to test methods under Sec.  
63.7(e)(2)(ii) and (f) and as defined in Sec.  63.90.
    (3) Approval of major alternatives to monitoring under Sec.  
63.8(f) and as defined in Sec.  63.90.
    (4) Approval of major alternatives to recordkeeping and reporting 
under Sec.  63.10(f) and as defined in Sec.  63.90.


Sec.  63.8266  What definitions apply to this subpart?

    Terms used in this subpart are defined in the CAA, in Sec.  63.2, 
and in this section as follows:
    Aqueous liquid means a liquid mixture in which water is the 
predominant component.
    Brine means an aqueous solution of alkali metal chloride, as sodium 
chloride salt solution or potassium chloride salt solution, that is 
used in the electrolyzer as a raw material.
    By-product hydrogen stream means the hydrogen gas from each 
decomposer that passes through the hydrogen system and is burned as 
fuel, transferred to another process as raw material, or discharged 
directly to the atmosphere.
    Caustic means an aqueous solution of alkali metal hydroxide, as 
sodium hydroxide or potassium hydroxide, that is produced in the 
decomposer.
    Caustic basket means a fixture adjacent to the decomposer that 
contains a serrated funnel over which the caustic from the decomposer 
passes, breaking into droplets such that electric current is 
interrupted.
    Caustic system means all vessels, piping, and equipment that convey 
caustic and remove mercury from the caustic stream. The caustic system 
begins at the decomposer and ends after the primary filters.
    Cell room means a building or other structure in which one or more 
mercury cells are located.
    Continuous parameter monitoring system, or CPMS, means the total 
equipment that may be required to meet the data acquisition and 
availability requirements of this subpart, used to sample, condition 
(if applicable), analyze, and provide a record of process of control 
system parameters.
    Control device means a piece of equipment (such as condensers, 
coolers, chillers, heat exchangers, mist eliminators, absorption units, 
and adsorption units) that removes mercury from gaseous streams.
    Decomposer means the component of a mercury cell in which mercury 
amalgam and water react in bed of graphite packing (within a 
cylindrical vessel), producing caustic and hydrogen gas and returning 
mercury to its elemental form for re-use in the process.
    Deviation means any instance in which an affected source subject to 
this subpart, or an owner or operator of such a source:
    (1) Fails to meet any requirement or obligation established by this 
subpart including, but not limited to, any emission limitation 
(including any operating limit) or work practice standard;
    (2) Fails to meet any term or condition that is adopted to 
implement an applicable requirement in this subpart and that is 
included in the title V operating permit for any affected source 
required to obtain such a permit;
    (3) Fails to meet any emission limitation (including any operating 
limit) or work practice standard in this subpart during startup, 
shutdown, or malfunction, regardless of whether or not such failure is 
allowed by this subpart; or
    (4) Fails to take corrective actions within 48 hours that result in 
parameter monitoring values being within range.
    Electrolyzer means the main component of the mercury cell that 
consists of an elongated, shallow steel trough that holds a layer of 
mercury as a flowing cathode. The electrolyzer is enclosed by side 
panels and a top that suspends metal anodes. In the electrolyzer, brine 
is fed between a flowing mercury cathode and metal anodes in the 
presence of electricity to produce chlorine gas and an alkali metal-
mercury amalgam (mercury amalgam).
    Emission limitation means any emission limit or operating limit.
    End box means a component of a mercury cell for transferring 
materials between the electrolyzer and the decomposer. The inlet end 
box collects and combines raw materials at the inlet end of the cell, 
and the outlet end box separates and directs various materials either 
into the decomposer or out of the cell.
    End box ventilation system means all vessels, piping, and equipment 
that evacuate the head space of each mercury cell end box (and possibly 
other vessels and equipment) to the atmosphere. The end box ventilation 
system begins at the end box (and other vessel or equipment which is 
being evacuated) and terminates at the end box ventilation system vent. 
The end box ventilation system includes all control devices.
    End box ventilation system vent means the discharge point of the 
end box ventilation system to the atmosphere after all control devices.
    Hydrogen leak means hydrogen gas (containing mercury vapor) that is 
escaping from the decomposer or hydrogen system.
    Hydrogen system means all vessels, piping, and equipment that 
convey a by-product hydrogen stream. The hydrogen system begins at the 
decomposer and ends at the point just downstream of the last control 
device. The hydrogen system includes all control devices.
    In liquid mercury service means containing or coming in contact 
with liquid mercury.
    Liquid mercury accumulation means one or more liquid mercury 
droplets, or a pool of liquid mercury, present on the floor or other 
surface exposed to the atmosphere.
    Liquid mercury leak means the liquid mercury that is dripping or 
otherwise escaping from process equipment.
    Liquid mercury spill means a liquid mercury accumulation resulting 
from a liquid mercury that leaked from process equipment or that 
dripped during maintenance or handling.
    Mercury cell means a device consisting of an electrolyzer and 
decomposer, with one or more end boxes, a mercury pump, and other 
components linking the electrolyzer and decomposer.
    Mercury cell amalgam seal pot means a compartment through which 
mercury amalgam passes from an outlet end box to a decomposer.
    Mercury cell chlor-alkali plant means all contiguous or adjoining 
property that is under common control, where mercury cells are used to 
manufacture product chlorine, product caustic, and by-product hydrogen 
and where mercury may be recovered from wastes.
    Mercury cell chlor-alkali production facility means an affected 
source consisting of all cell rooms and ancillary operations used in 
the manufacture of product chlorine, product caustic, and by-product 
hydrogen at a mercury cell chlor-alkali plant.
    Mercury concentration CMS, or mercury concentration continuous 
monitoring system, means a CMS, as defined in Sec.  63.2, that 
continuously measures the concentration of mercury.
    Mercury-containing wastes means waste materials containing mercury, 
which are typically classified under Resource Conservation and Recovery 
Act (RCRA) solid waste designations. K071 wastes are sludges from the 
brine system. K106 are wastewater treatment sludges. D009 wastes are 
non-specific mercury-containing wastes, further classified as either 
debris or nondebris (i.e., cell room sludges and carbon from 
decomposes).
    Mercury pump means a component of a mercury cell for conveying 
elemental mercury re-created in the decomposer to

[[Page 70939]]

the beginning of the mercury cell. A mercury pump is typically found 
either as an in-line mercury pump (near a mercury suction pot or 
mercury seal pot) or submerged mercury pump (within a mercury pump tank 
or mercury pump seal).
    Mercury recovery facility means an affected source consisting of 
all processes and associated operations needed for mercury recovery 
from wastes at a mercury cell chlor-alkali plant.
    Mercury thermal recovery unit means the retort(s) where mercury-
containing wastes are heated to volatilize mercury and the mercury 
recovery/control system (control devices and other equipment) where the 
retort off-gas is cooled, causing mercury to condense and liquid 
mercury to be recovered.
    Mercury thermal recovery unit vent means the discharge point of the 
mercury thermal recovery unit to the atmosphere after all recovery/
control devices. This term encompasses both oven type vents and non-
oven type vents.
    Mercury vacuum cleaner means a cleanup device used to draw a liquid 
mercury spill or accumulation (via suction pressure) into a closed 
compartment.
    Non-oven type mercury thermal recovery unit vent means the 
discharge point to the atmosphere after all recovery/control devices of 
a mercury thermal recovery unit in which the retort is either a rotary 
kiln or single hearth retort.
    Open-top container means any container that does not have a tight-
fitting cover that keeps its contents from being exposed to the 
atmosphere.
    Oven type mercury thermal recovery unit vent means the discharge 
point to the atmosphere after all recovery/control devices of a mercury 
thermal recovery unit in which each retort is a batch oven retort.
    Responsible official means responsible official as defined in 40 
CFR 70.2.
    Retort means a furnace where mercury-containing wastes are heated 
to drive mercury into the gas phase. The types of retorts used as part 
of mercury thermal recovery units at mercury cell chlor-alkali plants 
include batch oven retorts, rotary kilns, and single hearth retorts.
    Spalling means fragmentation by chipping.
    Sump means a large reservoir or pit for wastewaters (primarily 
washdown waters).
    Trench means a narrow channel or depression built into the length 
of a cell room floor that leads washdown materials to a drain.
    Vent hose means a connection for transporting gases from the 
mercury cell.
    Virgin mercury means mercury that has not been processed in an 
onsite mercury thermal recovery unit or otherwise recovered from 
mercury-containing wastes onsite.
    Washdown means the act of rinsing a floor or surface with a stream 
of aqueous liquid to cleanse it of a liquid mercury spill or 
accumulation, generally by driving it into a trench.
    Week means any consecutive seven-day period.
    Work practice standard means any design, equipment, work practice, 
or operational standard, or combination thereof, that is promulgated 
pursuant to section 112(h) of the CAA.

Tables to Subpart IIIII of Part 63

 Table 1 to Subpart IIIII of Part 63.--Work Practice Standards--Design,
                 Operation, and Maintenance Requirements
 [As stated in Sec.   63.8192, you must meet the work practice standards
                         in the following table]
------------------------------------------------------------------------
             For * * *                         You must * * *
------------------------------------------------------------------------
1. Cell rooms.....................  a. For new or modified cell rooms,
                                     construct each cell room interior
                                     using materials that are resistant
                                     to absorption of mercury, resistant
                                     to corrosion, facilitate the
                                     detection of liquid mercury spills
                                     or accumulations, and are easy to
                                     clean.
                                    b. Limit access around and beneath
                                     mercury cells in each cell room to
                                     prevent liquid mercury from being
                                     tracked into other areas.
                                    c. Provide adequate lighting in each
                                     cell room to facilitate the
                                     detection of liquid mercury spills
                                     or accumulations.
                                    d. Minimize the number of items
                                     stored around and beneath cells in
                                     each cell room.
2. Mercury cells and electrolyzers  a. Operate and maintain each
                                     electrolyzer, decomposer, end box,
                                     and mercury pump to minimize
                                     leakage of mercury.
                                    b. Prior to opening an electrolyzer
                                     for maintenance, do the following:
                                     (1) Complete work that can be done
                                     before opening the electrolyzer in
                                     order to minimize the time required
                                     to complete maintenance when the
                                     electrolyzer is open; (2) fill the
                                     electrolyzer with an aqueous
                                     liquid, when possible; (3) allow
                                     the electrolyzer to cool before
                                     opening; and (4) schedule and staff
                                     maintenance of the electrolyzer to
                                     minimize the time the electrolyzer
                                     is open.
                                    c. When the electrolyzer top is
                                     raised and before moving the top
                                     and anodes, thoroughly flush all
                                     visible mercury from the top and
                                     the anodes with an aqueous liquid,
                                     when possible.
                                    d. While an electrolyzer is open,
                                     keep the bottom covered with an
                                     aqueous liquid or maintain a
                                     continuous flow of aqueous liquid,
                                     when possible.
                                    e. During an electrolyzer side panel
                                     change, take measures to ensure an
                                     aqueous liquid covers or flows over
                                     the bottom, when possible.
                                    f. Each time an electrolyzer is
                                     opened, inspect and replace
                                     components, as appropriate.
                                    g. If you step into an electrolyzer
                                     bottom, either remove all visible
                                     mercury from your footwear or
                                     replace them immediately after
                                     stepping out of the electrolyzer.
                                    h. If an electrolyzer is
                                     disassembled for overhaul
                                     maintenance or for any other
                                     reason, chemically clean the bed
                                     plate or thoroughly flush it with
                                     an aqueous liquid.
                                    i. Before transporting each
                                     electrolyzer part to another work
                                     area, remove all visible mercury
                                     from the part or contain the part
                                     to prevent mercury from dripping
                                     during transport.
                                    j. After completing maintenance on
                                     an electrolyzer, check any mercury
                                     piping flanges that were opened for
                                     liquid mercury leaks.
                                    k. If a liquid mercury spill occurs
                                     during any maintenance activity on
                                     an electrolyzer, clean it up in
                                     accordance with the requirements in
                                     Table 3 to this subpart.

[[Page 70940]]

 
3. Vessels in liquid mercury        If you replace a vessel containing
 service.                            mercury that is intended to trap
                                     and collect mercury after December
                                     19, 2003, replace it with a vessel
                                     that has a cone shaped bottom with
                                     a drain valve or other design that
                                     readily facilitates mercury
                                     collection.
4. Piping and process lines in      a. To prevent mercury buildup after
 liquid mercury service.             December 19, 2003, equip each new
                                     process line and piping system with
                                     smooth interiors and adequate low
                                     point drains or mercury knock-out
                                     pots to avoid liquid mercury
                                     buildup within the pipe and to
                                     facilitate mercury collection and
                                     recovery.
5. Cell room floors...............  a. Maintain a coating on cell room
                                     floors that is resistant to
                                     absorption of mercury and that
                                     facilitates the detection of liquid
                                     mercury spills or accumulations.
                                    b. Maintain cell room floors such
                                     that they are smooth and free of
                                     cracking and spalling.
                                    c. Maintain the cell room floor to
                                     prevent mercury accumulation in the
                                     corners.
                                    d. Maintain a layer of aqueous
                                     liquid on liquid mercury contained
                                     in trenches or drains and replenish
                                     the aqueous layer at least once per
                                     day.
                                    e. Keep the cell room floor clean
                                     and free of debris.
                                    f. If you step into a liquid mercury
                                     spill or accumulation, either
                                     remove all visible mercury from
                                     your footwear or replace your
                                     footwear immediately.
6. End boxes......................  a. Either equip each end box with a
                                     fixed cover that is leak tight, or
                                     route the end box head space to an
                                     end box ventilation system.
                                    b. For each end box ventilation
                                     system: maintain a flowof aqueous
                                     liquid over the liquid mercury in
                                     the end box and maintain the
                                     temperature of the aqueous liquid
                                     below its boiling point, maintain a
                                     negative pressure in the end box
                                     ventilation system, and maintain
                                     the end box ventilation system in
                                     good condition.
                                    c. Maintain each end box cover in
                                     good condition and keep the end box
                                     closed when the cell is in service
                                     and when liquid mercury is flowing
                                     down the cell, except when
                                     operation or maintenance activities
                                     require short-term access.
                                    d. Keep all bolts and C-clamps used
                                     to hold the covers in place when
                                     the cell is in service and when
                                     liquid mercury is flowing down the
                                     cell.
                                    e. Maintain each access port stopper
                                     in an end box cover in good sealing
                                     condition and keep each end box
                                     access port closed when the cell is
                                     in service and when liquid mercury
                                     is flowing down the cell.
7. Decomposers....................  a. Maintain each decomposer cover in
                                     good condition and keep each
                                     decomposer closed and sealed,
                                     except when maintenance activities
                                     require the cover to be removed.
                                    b. Maintain connections between the
                                     decomposer and the corresponding
                                     cell components, hydrogen system
                                     piping, and caustic system piping
                                     in good condition and keep the
                                     connections closed/tight, except
                                     when maintenance activities require
                                     opening/loosening these
                                     connections.
                                    c. Keep each mercury cell amalgam
                                     seal pot closed and sealed, except
                                     when operation or maintenance
                                     activities require short-term
                                     access.
                                    d. Prior to opening a decomposer, do
                                     the following: fill the decomposer
                                     with an aqueous liquid or drain the
                                     decomposer liquid mercury into a
                                     container that meets requirements
                                     in Table 1, Item 9 or 10, allow the
                                     decomposer to cool before opening,
                                     and complete work that can be done
                                     before opening the decomposer.
                                    e. Take precautions to avoid mercury
                                     spills when changing graphite grids
                                     or balls in horizontal decomposers
                                     or graphite packing in vertical
                                     decomposers. If a spill occurs, you
                                     must clean it up in accordance with
                                     the requirements in Table 3 to this
                                     subpart.
                                    f. After each maintenance activity,
                                     use an appropriate technique (Table
                                     6 to this subpart) to check for
                                     hydrogen leaks.
                                    g. Before transporting any internal
                                     part from the decomposer (such as
                                     the graphite basket) to another
                                     work area, remove all visible
                                     mercury from the part or contain
                                     the part to prevent mercury from
                                     dripping during transport.
                                    h. Store carbon from decomposers in
                                     accordance with the requirements in
                                     40 CFR part 265, subparts I and CC,
                                     until the carbon is treated or is
                                     disposed.
8. Submerged mercury pumps........  a. Provide a vapor outlet connection
                                     from each submerged pump to an end
                                     box ventilation system. The
                                     connection must be maintained under
                                     negative pressure.
                                    b. Keep each mercury pump tank
                                     closed, except when maintenance or
                                     operation activities require the
                                     cover to be removed.
                                    c. Maintain a flow of aqueous liquid
                                     over the liquid mercury in each
                                     mercury pump tank and maintain the
                                     aqueous liquid at a temperature
                                     below its boiling point.
9. Open-top containers holding      Maintain a layer of aqueous liquid
 liquid mercury.                     over liquid mercury in each open-
                                     top container. Replenish the
                                     aqueous layer at least once per day
                                     and, when necessitated by operating
                                     procedures or observation, collect
                                     the liquid mercury from the
                                     container in accordance with the
                                     requirements in Table 4 to this
                                     subpart.
10. Closed containers used to       a. Store liquid mercury in
 store liquid mercury.               containers with tight fitting
                                     covers.
                                    b. Maintain the seals on the covers
                                     in good condition.
                                    c. Keep each container securely
                                     closed when mercury is not being
                                     added to, or removed from, the
                                     container.
11. Caustic systems...............  a. Maintain the seal between each
                                     caustic basket cover and caustic
                                     basket by using gaskets and other
                                     appropriate material.
                                    b. Do not allow solids and liquids
                                     collected from back-flushing
                                     primary caustic filters to contact
                                     floors or run into open trenches.
                                    c. Collect solids and liquids from
                                     back-flushing each primary caustic
                                     filter and collect these mercury-
                                     containing wastes in process
                                     vessels or in accordance with the
                                     requirements in 40 CFR part 265,
                                     subparts I and CC.

[[Page 70941]]

 
                                    d. Keep each caustic basket closed
                                     and sealed, except when operation
                                     or maintenance activities require
                                     short term access.
12. Hydrogen systems..............  a. Collect drips from each hydrogen
                                     seal pot and compressor seal in
                                     containers meeting the requirements
                                     in this table for open containers.
                                     These drips should not be allowed
                                     to run on the floor or in open
                                     trenches.
                                    b. Minimize purging of hydrogen from
                                     a decomposer into the cell room by
                                     either sweeping the decomposer with
                                     an inert gas or by routing the
                                     hydrogen to the hydrogen system.
                                    c. Maintain hydrogen piping gaskets
                                     in good condition.
                                    d. After any maintenance activities,
                                     use an appropriatetechnique (Table
                                     6 to this subpart) to check all
                                     hydrogen piping flanges that were
                                     opened for hydrogen leaks.
------------------------------------------------------------------------


               Table 2 to Subpart IIIII of Part 63.--Work Practice Standards--Required Inspections
         [As stated in Sec.   63.8192, you must meet the work practice standards in the following table]
----------------------------------------------------------------------------------------------------------------
                                      At least once each * * *
       You must inspect * . *                                    And if you find * * *        You must * * *
----------------------------------------------------------------------------------------------------------------
1. Each vent hose on each mercury     Half day................  A leaking vent hose....  Take action immediately
 cell.                                                                                    to correct the leak.
2. Each open-top container holding    Half day................  Liquid mercury that is   Take action immediately
 liquid mercury.                                                 not covered by an        to cover the liquid
                                                                 aqueous liquid.          mercury with an
                                                                                          aqueous liquid.
3. Each end box.....................  Half day................  a. An end box cover not  Take action immediately
                                                                 securely in place.       to put the end box
                                                                                          cover securely in
                                                                                          place.
                                                                b. An end box stopper    Take action immediately
                                                                 not securely in place.   to put the end box
                                                                                          stopper securely in
                                                                                          place.
                                                                c. Liquid mercury in an  Take action immediately
                                                                 end box that is not      to cover the liquid
                                                                 covered by an aqueous    mercury with an
                                                                 liquid at a              aqueous liquid.
                                                                 temperature below
                                                                 boiling.
4. Each mercury amalgam seal pot....  Half day................  A seal pot cover that    Take action immediately
                                                                 is not securely in       to put the seal pot
                                                                 place.                   cover securely in
                                                                                          place.
5. Each mercury seal pot............  Half day................  A mercury seal pot       Take action immediately
                                                                 stopper not securely     to put the mercury
                                                                 in place.                seal pot stopper
                                                                                          securely in place.
6. Cell room floors.................  Month...................  Cracks, spalling, or     Repair the crack,
                                                                 other deficiencies       spalling, or other
                                                                 that could cause         deficiency within 1
                                                                 liquid mercury to        month from the time
                                                                 become trapped.          you identify the
                                                                                          deficiency.
7. Pillars and beams................  6 months................  Cracks, spalling, or     Repair the crack,
                                                                 other deficiencies       spalling, or other
                                                                 that could cause         deficiency within 1
                                                                 liquid mercury to        month from the time
                                                                 become trapped.          you identify the
                                                                                          deficiency.
8. Each caustic basket..............  Half day................  A caustic basket cover   Take action immediately
                                                                 that is not securely     to put the caustic
                                                                 in place.                basket cover securely
                                                                                          in place.
9. All equipment and piping in the    Day.....................  Equipment that is        Initiate repair of the
 caustic system.                                                 leaking caustic.         leaking equipment
                                                                                          within 72 hours from
                                                                                          the time that you
                                                                                          identify the caustic
                                                                                          leak.
10. All floors and other surfaces     Half day................  A liquid mercury spill   Take the required
 where liquid mercury could                                      or accumulation.         action specified in
 accumulate in cell rooms and other                                                       Table 3 to this
 production facilities and in                                                             subpart.
 mercury recovery facilities.
11. Each electrolyzer bottom,         Day.....................  Equipment that is        Take the required
 electrolyzer side panel, end box,                               leaking liquid mercury.  action specified in
 mercury amalgam seal pot,                                                                Table 3 to this
 decomposer, mercury pump, and                                                            subpart.
 hydrogen cooler, and all other
 vessels, piping, and equipment in
 liquid mercury service in the cell
 room.
12. Each decomposer and all hydrogen  Half day................  Equipment that is        Take the required
 piping up to the hydrogen header.                               leaking hydrogen and/    action specified in
                                                                 or mercury vapor.        Table 3 to this
                                                                                          subpart.
13. All equipment in the hydrogen     3 months................  Equipment that is        Take the required
 system from the start of the header                             leaking hydrogen and/    action specified in
 to the last control device.                                     or mercury vapor.        Table 3 to this
                                                                                          subpart.
----------------------------------------------------------------------------------------------------------------


[[Page 70942]]


 Table 3 to Subpart IIIII of Part 63.--Work Practice Standards--Required
  Actions for Liquid Mercury Spills and Accumulations and Hydrogen and
                           Mercury Vapor Leaks
 [As stated in Sec.   63.8192, you must meet the work practice standards
                         in the following table]
------------------------------------------------------------------------
During a required inspection or at
 any other time, If you find * * *             You must * * *
 
------------------------------------------------------------------------
1. A liquid mercury spill or        a. Initiate clean up of the liquid
 accumulation.                       mercury spill or accumulation as
                                     soon as possible, but no later than
                                     1 hour from the time you detect it.
                                    b. Clean up liquid mercury using a
                                     mercury vacuum cleaner or by using
                                     an alternative method. If you use
                                     an alternative method to clean up
                                     liquid mercury, you must submit a
                                     description of the method to the
                                     Administrator in your Notification
                                     of Compliance Status report.
                                    c. If you use a mercury vacuum
                                     cleaner, the vacuum cleaner must be
                                     designed to prevent generation of
                                     airborne mercury; you must cap the
                                     ends of hoses after each use; and
                                     after vacuuming, you must wash down
                                     the area.
                                    d. Inspect all equipment in liquid
                                     mercury service in the surrounding
                                     area to identify the source of the
                                     liquid mercury within 1 hour from
                                     the time you detect the liquid
                                     mercury spill or accumulation.
                                    e. If you identify leaking equipment
                                     as the source of the spill or
                                     accumulation, contain the dripping
                                     mercury, stop the leak, and repair
                                     the leaking equipment as specified
                                     below.
                                    f. If you cannot identify the source
                                     of the liquid mercury spill or
                                     accumulation, re-inspect the area
                                     within 6 hours of the time you
                                     detected the liquid mercury spill
                                     or accumulation, or within 6 hours
                                     of the last inspection of the area.
2. Equipment that is leaking        a. Contain the liquid mercury
 liquid mercury.                     dripping from the leaking equipment
                                     by placing a container under the
                                     leak within 30 minutes from the
                                     time you identify the liquid
                                     mercury leak.
                                    b. The container must meet the
                                     requirement for open-top containers
                                     in Table 1 to this subpart.
                                    c. Make a first attempt at stopping
                                     the leak within 1 hour from the
                                     time you identify the liquid
                                     mercury leak.
                                    d. Stop the leak and repair the
                                     leaking equipment within 4 hours
                                     from the time you identify the
                                     liquid mercury leak.
                                    e. You can delay repair of equipment
                                     leaking liquid mercury if you
                                     either isolate the leaking
                                     equipment from the process so that
                                     it does not remain in mercury
                                     service; or determine that you
                                     cannot repair the leaking equipment
                                     without taking the cell off line,
                                     provided that you contain the
                                     dripping mercury at all times as
                                     described above, and take the cell
                                     off line as soon as practicable,
                                     but no later than 48 hours from the
                                     time you identify the leaking
                                     equipment. You cannot place the
                                     cell back into service until the
                                     leaking equipment is repaired.
3. A decomposer or hydrogen system  a. Make a first attempt at stopping
 piping up to the hydrogen header    the leak within 1 hour from the
 that is leaking hydrogen and/or     time you identify the hydrogen and/
 mercury vapor.                      or mercury vapor leak.
                                    b. Stop the leak and repair the
                                     leaking equipment within 4 hours
                                     from the time you identify the
                                     hydrogen and/or mercury vapor leak.
                                    c. You can delay repair of a
                                     equipment leaking hydrogen and/or
                                     mercury vapor if you isolate the
                                     leaking equipment or take the cell
                                     off line until you repair the
                                     leaking equipment.
4. Equipment in the hydrogen        a. Make a first attempt at stopping
 system, from the start of the       the leak within 4 hours from the
 hydrogen header to the last         time you identify the hydrogen and/
 control device, that is leaking     or mercury vapor leak.
 hydrogen and/or mercury vapor.
                                    b. Stop the leak and repair the
                                     header within 24 hours from the
                                     time you identify the hydrogen and/
                                     or mercury vapor leak.
                                    c. You can delay repair of equipment
                                     leaking hydrogen and/or mercury
                                     vapor if you isolate the leaking
                                     equipment.
------------------------------------------------------------------------


    Table 4 to Subpart IIIII of Part 63.--Work Practice Standards--Requirements for Mercury Liquid Collection
         [As stated in Sec.   63.8192, you must meet the work practice standards in the following table]
----------------------------------------------------------------------------------------------------------------
 
-------------------------------------------------------------------------
You must collect liquid mercury    At the following        When collecting the mercury, you must meet these
 from * * *                            intervals                              requirements
----------------------------------------------------------------------------------------------------------------
1. Open-top containers..........  a. At least once    i. If you spill     ii. From the time   iii. Within 4
                                   each 72 hours.      liquid mercury      that you collect    hours from the
                                                       during collection   liquid mercury      time you` collect
                                                       or transport, you   into a temporary    the liquid
                                                       must take the       container until     mercury, you must
                                                       action specified    the time that you   transfer it from
                                                       in Table 3 to       store the liquid    each temporary
                                                       this subpart for    mercury, you must   container to a
                                                       liquid mercury      keep it covered     storage container
                                                       spills and          by an aqueous       that meets the
                                                       accumulations.      liquid.             specifications in
                                                                                               Table 1 to this
                                                                                               subpart.
2. Vessels, low point drains,     a. At least once    See 1.a.i through
 mercury knock-out pots, and       each week.          iii above.
 other closed mercury collection
 points.

[[Page 70943]]

 
3. All other equipment..........  a. Whenever         See 1.a.i. through
                                   maintenance         iii above.
                                   activities
                                   require the
                                   opening of the
                                   equipment.
----------------------------------------------------------------------------------------------------------------


   Table 5 to Subpart IIIII.--Required Elements of Floor-Level Mercury
            Vapor Measurement and Cell Room Monitoring Plans
    [Your Floor-Level Mercury Vapor Measurement Plan required by Sec.
 63.8192(d) and Cell Room Monitoring Plan required by Sec.   63.8192(g)
        must contain the elements listed in the following table]
------------------------------------------------------------------------
 You must specify in your plan * *
                 *                         Additional requirements
------------------------------------------------------------------------
               Floor-Level Mercury Vapor Measurement Plan
------------------------------------------------------------------------
1. Locations in the cell room       The locations must be representative
 where you will measure the level    of the entire cell room floor area.
 of mercury vapor.                   At a minimum you must measure the
                                     level of mercury vapor above
                                     mercury-containing cell room
                                     equipment, as well as areas around
                                     the cells, decomposes, or other
                                     mercury-containing equipment.
2. Equipment or sampling and        If an instrument or other equipment
 analytical methods that you will    is used, the plan must include
 use to measure the level of         manufacturer specifications and
 mercury vapor.                      calibration procedures. The plan
                                     must also include a description of
                                     how you will ensure that the
                                     instrument will be calibrated and
                                     maintained according to
                                     manufacturer specifications.
3. Measurement frequency..........  Measurements must take place at
                                     least once each half day.
4. Number of measurements.........  At least three readings must be
                                     taken at each sample location and
                                     the average of these readings must
                                     be recorded.
5. A floor-level mercury            The action level may not be higher
 concentration action level.         than 0.05 mg/m3.
------------------------------------------------------------------------
                        Cell Room Monitoring Plan
------------------------------------------------------------------------
1. Details of your mercury
 monitoring system.
2. How representative sampling      Include some pre-plan measurements
 will be conducted.                  to demonstrate the profile of
                                     mercury concentration in the cell
                                     room and how the selected sampling
                                     locations ensure conducted
                                     representativeness.
3. Quality assurance/quality        Include a description of how you
 control procedures for your         will keep records or other means to
 mercury monitoring system.          demonstrate that the system is
                                     operating properly.
4. Your action level..............  Include the background data used to
                                     establish your level.
------------------------------------------------------------------------


    Table 6 to Subpart IIIII of Part 63.--Examples of Techniques for
   Equipment Problem Identification, Leak Detection and Mercury Vapor
                              Measurements
  [As stated in Tables 1 and 2 of Subpart IIIII, examples of techniques
 for equipment problem identification, leak detection and mercury vapor
            measurements can be found in the following table]
------------------------------------------------------------------------
                                   You could use * *     Principle of
         To detect * * *                   *            detection * * *
------------------------------------------------------------------------
1. Leaking vent hoses; liquid     Visual inspections
 mercury that is not covered by
 an aqueous liquid in open-top
 containers or end boxes; end
 box covers or stoppers, amalgam
 seal pot stoppers, or caustic
 basket covers not securely in
 place; cracks or spalling in
 cell room floors, pillars, or
 beams; caustic leaks; liquid
 mercury accumulations or
 spills; and equipment that is
 leaking liquid mercury.
2. Equipment that is leaking      a. Auditory and
 hydrogen and/or mercury vapor     visual
 during inspections required by    inspections
 Table 2 to this subpart.
                                  b. Portable         A sample of gas is
                                   mercury vapor       drawn through a
                                   analyzer--ultravi   detection cell
                                   olet light          where ultraviolet
                                   absorption          light at 253.7
                                   detector.           nanometers (nm)
                                                       is directed
                                                       perpendicularly
                                                       through the
                                                       sample toward a
                                                       photodetector.
                                                       Elemental mercury
                                                       absorbs the
                                                       incident light in
                                                       proportion to its
                                                       concentration in
                                                       the air stream.
                                  c. Portable         A sample of gas is
                                   mercury vapor       drawn through a
                                   analyzer--gold      detection cell
                                   film amalgamation   containing a gold
                                   detector.           film detector.
                                                       Elemental mercury
                                                       amalgamates with
                                                       the gold film,
                                                       changing the
                                                       resistance of the
                                                       detector in
                                                       proportion to the
                                                       mercury
                                                       concentration in
                                                       the air sample.

[[Page 70944]]

 
                                  d. Portable short-  Ultraviolet light
                                   wave ultraviolet    is directed
                                   light,              toward a
                                   fluorescent         fluorescent
                                   background--visua   background
                                   l indication.       positioned behind
                                                       a suspected
                                                       source of mercury
                                                       emissions.
                                                       Elemental mercury
                                                       vapor absorbs the
                                                       ultraviolet
                                                       light, projecting
                                                       a dark shadow
                                                       image on the
                                                       fluorescent
                                                       background.
                                  e. Portable
                                   combustible gas
                                   meter.
3. Level of mercury vapor in the  a. Portable         See Item 2.b.
 cell room and other areas.        mercury vapor
                                   analyzer--ultravi
                                   olet light
                                   absorption
                                   detector.
                                  b. Portable         See Item 2.c.
                                   mercury vapor
                                   analyzer--gold
                                   film amalgamation
                                   detector.
                                  c. Permanganate     A known volume of
                                   impingement.        gas sample is
                                                       absorbed in
                                                       potassium
                                                       permanganate
                                                       solution.
                                                       Elemental mercury
                                                       in the solution
                                                       is determined
                                                       using a cold
                                                       vapor adsorption
                                                       analyzer, and the
                                                       concentration of
                                                       mercury in the
                                                       gas sample is
                                                       calculated.
------------------------------------------------------------------------


   Table 7 to Subpart IIIII of Part 63.--Required Elements of Washdown
                                  Plans
  [As stated in Sec.   63.8192, your written washdown plan must address
             the elements contained in the following table]
------------------------------------------------------------------------
                                              You must establish the
 For each of the following areas * * *    following as part of your plan
                                                      * * *
------------------------------------------------------------------------
1. Center aisles of cell rooms.........  A description of the manner of
                                          washdown of the area, and the
                                          washdown frequency for the
                                          area.
2. Electrolyzers
3. End boxes and areas under end boxes
4. Decomposers and areas under
 decomposers
5. Caustic baskets and areas around
 caustic baskets
6. Hydrogen system piping
7. Basement floor of cell rooms
8. Tanks
9. Pillars and beams in cell rooms
10. Mercury cell repair areas
11. Maintenance shop areas
12. Work tables
13. Mercury thermal recovery units
14. Storage areas for mercury-
 containing wastes
------------------------------------------------------------------------


    Table 8 to Subpart IIIII of Part 63.--Requirements for Cell Room
                           Monitoring Program
 [As stated in Sec.   63.8192(g)(1), your mercury monitoring system must
         meet the requirements contained in the following table]
------------------------------------------------------------------------
     If you utilize an * * *          Your * * *          Must * * *
------------------------------------------------------------------------
1. Extractive cold vapor          a. Mercury vapor    Be capable of
 spectroscopy system.              analyzer.           continuously
                                                       monitoring the
                                                       elemental mercury
                                                       concentration
                                                       with a detection
                                                       level at least
                                                       two times lower
                                                       than the baseline
                                                       mercury
                                                       concentration in
                                                       the cell room.
                                  b. Sampling system  Obtain
                                                       measurements at
                                                       three or more
                                                       locations along
                                                       the center aisle
                                                       of the cell room
                                                       at a height
                                                       sufficient to
                                                       ensure that
                                                       sample is
                                                       representative of
                                                       the entire cell
                                                       room. One
                                                       sampling location
                                                       must be above the
                                                       midpoint of the
                                                       center aisle, and
                                                       the other two an
                                                       equidistance
                                                       between the
                                                       midpoint and the
                                                       end of the cells.
2. Open path differential         a. Mercury vapor    Be capable of
 optical absorption spectroscopy   analyzer.           continuously
 system.                                               monitoring the
                                                       elemental mercury
                                                       concentration
                                                       with a detection
                                                       level at least
                                                       two times lower
                                                       than the baseline
                                                       mercury
                                                       concentration in
                                                       the cell room.
                                  b. Path...........  Be directed along
                                                       the center aisle
                                                       at a height
                                                       sufficient to
                                                       ensure that the
                                                       sample is
                                                       representative of
                                                       the entire cell
                                                       room.
------------------------------------------------------------------------


[[Page 70945]]


Table 9 to Subpart IIIII of Part 63.--Required Records for Work Practice
                                Standards
 [As stated in Sec.   63.8256(c), you must keep the records (related to
     the work practice standards) specified in the following table]
------------------------------------------------------------------------
                                          You must record the following
             For each * * *                     information * * *
------------------------------------------------------------------------
1. Inspection required by Table 2 to     Date and time the inspection
 this subpart.                            was conducted.
2. Situation found during an inspection  a. Description of the
 required by Table 2 to this subpart:     condition.
 leaking vent hose; open-top container   b. Location of the condition.
 where liquid mercury is not covered by  c. Date and time you identify
 an aqueous liquid; end box cover that    the condition.
 is not securely in place; end box       d. Description of the
 stopper that is not securely in place;   corrective action taken.
 end box where liquid mercury is not     e. Date and time you
 covered by an aqueous liquid at a        successfully complete the
 temperature below boiling; seal pot      corrective action.
 cover that is not securely in place;
 open or mercury seal pot stopper that
 is not securely in place; crack,
 spalling, or other deficiency in a
 cell room floor, pillar, or beam that
 could cause liquid mercury to become
 trapped; or caustic basket that is not
 securely in place.
3. Caustic leak during an inspection     a. Location of the leak.
 required by Table 2 to this subpart.    b. Date and time you identify
                                          the leak.
                                         c. Date and time you
                                          successfully stop the leak and
                                          repair the leaking equipment.
4. Liquid mercury spill or accumulation  a. Location of the liquid
 identified during an inspection          mercury spill or accumulation.
 required by Table 2 to this subpart or  b. Estimate of the weight of
 at any other time.                       liquid mercury.
                                         c. Date and time you detect the
                                          liquid mercury spill or
                                          accumulation.
                                         d. Method you use to clean up
                                          the liquid mercury spill or
                                          accumulation.
                                         e. Date and time when you clean
                                          up the liquid mercury spill or
                                          accumulation.
                                         f. Source of the liquid mercury
                                          spill or accumulation.
                                         g. If the source of the liquid
                                          mercury spill or accumulation
                                          is not identified, the time
                                          when you reinspect the area.
5. Liquid mercury leak or hydrogen leak  a. Location of the leak.
 identified during an inspection         b. Date and time you identify
 required by Table 2 to this subpart or   the leak.
 at any other time.                      c. If the leak is a liquid
                                          mercury leak, the date and
                                          time that you successfully
                                          contain the dripping liquid
                                          mercury.
                                         d. Date and time you first
                                          attempt to stop the leak.
                                         e. Date and time you
                                          successfully stop the leak and
                                          repair the leaking equipment.
                                         f. If you take a cell off line
                                          or isolate the leaking
                                          equipment, the date and time
                                          you take the cell off line or
                                          isolate the leaking equipment,
                                          and the date and time you put
                                          the cell or isolated equipment
                                          back into service.
6. Occasion for which it is not          a. Reason for not being able to
 possible to perform the design,          perform each procedure
 operation and maintenance procedures     determined to be not possible.
 required by Item 2 of Table 1 to this   b. Actions taken to reduce or
 subpart.                                 prevent mercury emissions, in
                                          lieu of the requirements in
                                          Table 1 to this subpart.
------------------------------------------------------------------------


           Table 10 to Subpart IIIII of Part 63.--Applicability of General Provisions to Subpart IIIII
 [As stated in Sec.   63.8262, you must comply with the applicable General Provisions requirements according to
                                              the following table]
----------------------------------------------------------------------------------------------------------------
                                                                   Applies to Subpart
               Citation                        Subject                   IIIII                 Explanation
----------------------------------------------------------------------------------------------------------------
Sec.   63.1..........................  Applicability..........  Yes....................
Sec.   63.2..........................  Definitions............  Yes....................
Sec.   63.3..........................  Units and Abbreviations  Yes....................
Sec.   63.4..........................  Prohibited Activities..  Yes....................
Sec.   63.5..........................  Construction/            Yes....................
                                        Reconstruction.
Sec.   63.6(a)-(g), (i), (j).........  Compliance with          Yes....................
                                        Standards and
                                        Maintenance
                                        Requirements.
Sec.   63.6(h).......................  Compliance with Opacity  No.....................  Subpart IIIII does not
                                        and Visible Emission                              have opacity and
                                        Standards.                                        visible emission
                                                                                          standards.
Sec.   63.7(a)(1), (b)-(h)...........  Performance Testing      Yes....................  Subpart IIIII specifies
                                        Requirements.                                     additional
                                                                                          requirements related
                                                                                          to site-specific test
                                                                                          plans and the conduct
                                                                                          of performance tests.
Sec.   63.7(a)(2)....................  Applicability and        No.....................  Subpart IIIII requires
                                        Performance Test Dates.                           the performance test
                                                                                          to be performed on the
                                                                                          compliance date.
Sec.   63.8(a)(1), (a)(3); (b);        Monitoring Requirements  Yes....................
 (c)(1)-(4), (6)-(8); (d); (e); and
 (f)(1)-(5).
Sec.   63.8(a)(2)....................  Continuous Monitoring    No.....................  Subpart IIIII requires
                                        System (CMS)                                      a site-specific
                                        Requirements.                                     monitoring plan in
                                                                                          lieu of a promulgated
                                                                                          performance
                                                                                          specification for a
                                                                                          mercury concentration
                                                                                          CMS.

[[Page 70946]]

 
Sec.   63.8(a)(4)....................  Additional Monitoring    No.....................  Subpart IIIII does not
                                        Requirements for                                  require flares.
                                        Control Devices in
                                        Sec.   63.11.
Sec.   63.8(c)(5)....................  COMS Minimum Procedures  No.....................  Subpart IIIII does not
                                                                                          have opacity and
                                                                                          visible emission
                                                                                          standards.
Sec.   63.8(f)(6)....................  Alternative to Relative  No.....................  Subpart IIIII does not
                                        Accuracy Test.                                    require CEMS.
Sec.   63.8(g).......................  Data Reduction.........  No.....................  Subpart IIIII specifies
                                                                                          mercury concentration
                                                                                          CMS data reduction
                                                                                          requirements.
Sec.   63.9(a)-(e), (g)-(j)..........  Notification             Yes....................
                                        Requirements.
Sec.   63.9(f).......................  Notification of VE/      No.....................  Subpart IIIII does not
                                        Opacity Test.                                     have opacity and
                                                                                          visible emission
                                                                                          standards.
Sec.   63.10(a); (b)(1); (b)(2)(i)-    Recordkeeping/Reporting  Yes....................
 (xii), (xiv); (b)(3); (c);(d)(1)-
 (2), (4)-(5); (e); (f).
Sec.   63.10(b)(2)(xiii).............  CMS Records for RATA     No.....................  Subpart IIIII does not
                                        Alternative.                                      require CEMS.
Sec.   63.10(d)(3)...................  Reporting Opacity or VE  No.....................  Subpart IIIII does not
                                        Observations.                                     have opacity and
                                                                                          visible emission
                                                                                          standards.
Sec.   63.11.........................  Flares.................  No.....................  Subpart IIIII does not
                                                                                          require flares.
Sec.   63.12.........................  Delegation.............  Yes....................
Sec.   63.13.........................  Addresses..............  Yes....................
Sec.   63.14.........................  Incorporation by         Yes....................
                                        Reference.
Sec.   63.15.........................  Availability of          Yes....................
                                        Information.
----------------------------------------------------------------------------------------------------------------

[FR Doc. 03-22926 Filed 12-18;-03; 8:45 am]
BILLING CODE 6560-50-P