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EO12866_Mercury Emissions from Mercury Cell Chlor‐Alkali Plants 2060‐AN99 NPRM Draft 

Preamble and Rule_20100702

6560-50-P

ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 63

[EPA-HQ-OAR-2002-0017; FRL- ]

RIN 2060-AN99

National Emission Standards for Hazardous Air Pollutants: 

Mercury Emissions from Mercury Cell Chlor-Alkali Plants

AGENCY: Environmental Protection Agency (EPA).

ACTION: Supplemental proposed rule.

SUMMARY: This action proposes amendments to the national 

emission standards for hazardous air pollutants (NESHAP) for 

mercury emissions from mercury cell chlor-alkali plants. On 

June 11, 2008, EPA proposed amendments to this NESHAP in 

response to a petition for reconsideration filed by the Natural 

Resources Defense Council (NRDC). This action is a supplement 

to the June 11, 2008, proposal, and revises certain aspects of 

the 2008 proposal while maintaining others. This action proposes 

to amend the NESHAP to prohibit emissions of mercury from 

mercury cell chlor-alkali production processes within three 

years from promulgation of the final rule. Facilities could 

meet these limits by either converting to nonmercury technology

or by ceasing their chlorine production operations. For all 

mercury recovery units, the proposed rule also prohibits mercury 
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emissions within three years from promulgation of the final 

rule. If promulgated, this supplemental proposed rule would 

eliminate approximately 640 pounds of annual mercury emissions, 

and result in reduced energy demand of around 350,000 megawatt 

hours per year, which is approximately equivalent to the energy 

produced in one year by a 40 megawatt power plant. In addition, 

this action proposes to amend the provisions of the existing 

NESHAP that apply to periods of startup, shutdown, and 

malfunction. Two amendments proposed on June 11, 2008 to 

correct compliance errors in the rule are being retained.

Specifically, these two amendments are related to the detection 

limit for continuous mercury analyzers and the frequency of 

determining compliance with the emissions standard for mercury 

recovery units. 

DATES: Comments. Comments must be received on or before 

[INSERT DATE 60 DAYS AFTER PUBLICATION IN THE FEDERAL REGISTER].

Public Hearing. If anyone contacts EPA by [INSERT DATE 15

DAYS AFTER PUBLICATION IN THE FEDERAL REGISTER] requesting to 

speak at a public hearing, a hearing will be held on [INSERT 

DATE 30 DAYS AFTER PUBLICATION IN THE FEDERAL REGISTER]. 

ADDRESSES: You may submit comments, identified by Docket ID No. 

EPA-HQ-OAR-2002-0017, by any of the following methods:
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• Federal eRulemaking Portal: 

http://www.regulations.gov: Follow the instructions 

for submitting comments.

• Agency Web Site: http://www.epa.gov/oar/docket.html. 

Follow the instructions for submitting comments on the 

EPA Air and Radiation Docket Web site.

• E-mail: a-and-r-docket@epa.gov. Include Docket ID 

No. EPA-HQ-OAR-2002-0017 in the subject line of the 

message.

• Fax: (202) 566-9744.

• Mail: National Emission Standards for Hazardous Air 

Pollutants for Mercury Cell Chlor-alkali Plants 

Docket, Environmental Protection Agency, EPA Docket 

Center (EPA/DC), Air and Radiation Docket, Mail Code 

2822T, 1200 Pennsylvania Ave., NW, Washington, DC 

20460. Please include a total of two copies. In 

addition, please mail a copy of your comments on the 

information collection provisions to the Office of 

Information and Regulatory Affairs, Office of 

Management and Budget (OMB), Attn: Desk Officer for 

EPA, 725 17th St., NW., Washington, DC 20503.

• Hand Delivery: EPA Docket Center, Public Reading 

Room, EPA West, Room 3334, 1301 Constitution Ave., NW, 

Washington, DC 20460. Such deliveries are only 
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accepted during the Docket’s normal hours of 

operation, and special arrangements should be made for 

deliveries of boxed information.

Instructions: Direct your comments to Docket ID No. EPAHQ-OAR-2002-0017. EPA’s policy is that all comments received 

will be included in the public docket without change and may be 

made available online at http://www.regulations.gov, including 

any personal information provided, unless the comment includes 

information claimed to be confidential business information 

(CBI) or other information whose disclosure is restricted by 

statute. Do not submit information that you consider to be CBI 

or otherwise protected through www.regulations.gov or e-mail. 

The www.regulations.gov Web site is an “anonymous access” 

system, which means EPA will not know your identity or contact 

information unless you provide it in the body of your comment. 

If you send an e-mail comment directly to EPA without going 

through www.regulations.gov, your e-mail address will be 

automatically captured and included as part of the comment that 

is placed in the public docket and made available on the 

Internet. If you submit an electronic comment, EPA recommends 

that you include your name and other contact information in the 

body of your comment and with any disk or CD-ROM you submit. If 

EPA cannot read your comment due to technical difficulties and 

cannot contact you for clarification, EPA may not be able to 
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consider your comment. Electronic files should avoid the use of 

special characters, any form of encryption, and be free of any 

defects or viruses.

Docket: All documents in the docket are listed in the 

www.regulations.gov index. Although listed in the index, some 

information is not publicly available, e.g., CBI or other 

information whose disclosure is restricted by statute. Certain 

other material, such as copyrighted material, is not placed on 

the Internet and will be publicly available only in hard copy 

form. Publicly available docket materials are available either 

electronically through www.regulations.gov or in hard copy at 

the National Emission Standards for Hazardous Air Pollutants for 

Mercury Cell Chlor-alkali Plants Docket, EPA/DC, EPA West, Room 

3334, 1301 Constitution Ave., NW, Washington, DC. The Public 

Reading Room is open from 8:30 a.m. to 4:30 p.m., Monday through 

Friday, excluding legal holidays. The telephone number for the 

Public Reading Room is (202) 566-1744, and the telephone number 

for the Air Docket is (202) 566-1742.

FOR FURTHER INFORMATION CONTACT: Dr. Donna Lee Jones, Sector 

Policies and Programs Division, Office of Air Quality Planning 

and Standards (D243-02), Environmental Protection Agency, 

Research Triangle Park, North Carolina 27711, telephone number: 

(919) 541-5251; fax number: (919) 541-3207; e-mail address: 

jones.donnalee@epa.gov. 
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SUPPLEMENTARY INFORMATION:

I. General Information

A. Does this action apply to me?

The regulated categories and entities potentially affected 

by this proposed action include:

Category NAICS code1 Examples of regulated entities

Industry. . . . . 325181 Alkalis and Chlorine 

Manufacturing

Federal government . . . . Not affected.

State/local/tribal 

government

. . . . Not affected.

1 North American Industry Classification System.

 

This table is not intended to be exhaustive, but rather 

provides a guide for readers regarding entities likely to be 

affected by this action. To determine whether your facility 

would be regulated by this action, you should examine the 

applicability criteria in 40 CFR 63.7682 of subpart IIIII,

National Emission Standards for Hazardous Air Pollutants 

(NESHAP): Mercury Emissions from Mercury Cell Chlor-Alkali

(hereafter called the “2003 Mercury Cell MACT”). If you have 

any questions regarding the applicability of this action to a 

particular entity, consult either the air permitting authority 

for the entity or your EPA regional representative as listed in 

40 CFR 63.13 of subpart A (General Provisions).

B. What should I consider as I prepare my comments to EPA?
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Do not submit information containing CBI to EPA through 

www.regulations.gov or e-mail. Send or deliver information 

identified as CBI only to the following address: Roberto 

Morales, OAQPS Document Control Officer (C404-02), Environmental 

Protection Agency, Office of Air Quality Planning and Standards, 

Research Triangle Park, North Carolina 27711, Attention Docket 

ID EPA-HQ-OAR-2002-0017. Clearly mark the part or all of the 

information that you claim to be CBI. For CBI information in a 

disk or CD ROM that you mail to EPA, mark the outside of the 

disk or CD ROM as CBI and then identify electronically within 

the disk or CD ROM the specific information that is claimed as 

CBI. In addition to one complete version of the comment that 

includes information claimed as CBI, a copy of the comment that 

does not contain the information claimed as CBI must be 

submitted for inclusion in the public docket. Information so 

marked will not be disclosed except in accordance with 

procedures set forth in 40 CFR part 2. 

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

In addition to being available in the docket, an electronic 

copy of this proposed action will also be available on the 

Worldwide Web (WWW) through the Technology Transfer Network 

(TTN). Following signature, a copy of this proposed action will 

be posted on the TTN’s policy and guidance page for newly 

proposed or promulgated rules at the following address: 
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http://www.epa.gov/ttn/oarpg/. The TTN provides information and 

technology exchange in various areas of air pollution control.

D. When would a public hearing occur?

If anyone contacts EPA requesting to speak at a public 

hearing concerning the proposed amendments by [INSERT DATE 10 

DAYS AFTER PUBLICATION IN THE FEDERAL REGISTER], we will hold a 

public hearing on [INSERT DATE 30 DAYS AFTER PUBLICATION IN THE 

FEDERAL REGISTER]. If you are interested in attending the 

public hearing, contact Ms. Pamela Garrett at (919) 541-7966 to 

verify that a hearing will be held. If a public hearing is 

held, it will be held at 10 a.m. at the EPA’s Environmental 

Research Center Auditorium, Research Triangle Park, NC, or an 

alternate site nearby.

E. How is this document organized?

The supplementary information in this preamble is organized 

as follows:

I. General Information

A. Does this action apply to me?

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

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

D. When would a public hearing occur?

E. How is this document organized?

II. Background Information

III.Summary of Proposed Amendments

A. What are the proposed amendments?

B. How do these proposed amendments relate to the amendments 

proposed on June 11, 2008?

IV. Rationale for Proposed Amendments

A. What is the basis for the proposed zero mercury standard?

1. Technical information and analyses

2. Rationale for selection of the zero mercury standard 
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B. What is the basis for the proposed rule changes related to 

startup, shutdown, and malfunction?

C. What is the basis for the proposed rule corrections?

D. What is our rationale for doing a supplemental proposal?

V. Impacts of Proposed Amendments

A. What are the cost and economic impacts of this proposal?

1. Cost impacts

2. Economic impacts

B. What are the environmental and energy impacts of this 

proposal?

VI. Statutory and Executive Order Reviews

A. Executive Order 12866: Regulatory Planning and Review

B. Paperwork Reduction Act

C. Regulatory Flexibility Act

D. Unfunded Mandates Reform Act

E. Executive Order 13132: Federalism

F. Executive Order 13175: Consultation and Coordination with 

Indian Tribal Governments

G. Executive Order 13045: Protection of Children from 

Environmental Health and Safety Risks

H. Executive Order 13211: Actions Concerning Regulations That 

Significantly Affect Energy Supply, Distribution, or Use

I. National Technology Transfer and Advancement Act

J. Executive Order 12898: Federal Actions to Address 

Environmental Justice in Minority Populations and LowIncome Populations

II. Background Information

On December 19, 2003, EPA promulgated the 2003 Mercury Cell 

MACT (40 CFR part 63, subpart IIIII, 68 FR 70904). This rule

for mercury cell chlor-alkali plants implements section 112(d) 

of the Clean Air Act (CAA), which requires all categories and 

subcategories of major 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 
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of section 112(c)(1) of the CAA. In addition, mercury cell 

chlor-alkali plants are listed as an area source category under 

section 112(c)(3) and (k)(3)(B) of the CAA. The 2003 Mercury 

Cell MACT satisfied our requirement to issue 112(d) regulations 

under each of these listings (for mercury). The 2003 Mercury 

Cell MACT required both existing major and area sources to meet 

mercury emission limits on stack emission sources from both 

chlorine production and from the recovery of mercury from wastes 

and other scrap in mercury thermal recovery units. The 2003 

Mercury Cell MACT also required the facilities to monitor and 

minimize fugitive mercury emissions from the cell room by 

conducting either daily work practices or work practices 

performed in response to high levels of mercury emissions 

determined from continuous mercury monitoring. The 2003 rule 

required facilities to comply with applicable emission 

limitations and work practice requirements at all times, except 

during periods of startup, shutdown, and malfunction. Finally, 

the 2003 Mercury Cell MACT prohibited mercury emissions from new 

and reconstructed facilities. 

On February 17, 2004, the Natural Resources Defense Council 

(NRDC) submitted an administrative petition to EPA asking us to 

reconsider several aspects of the 2003 Mercury Cell MACT under 

CAA section 307(d)(7)(B). In the administrative petition, the 

NRDC requested that EPA reconsider: (1) the decision to develop 
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a set of work practice requirements under CAA section 112(h) in 

lieu of a numeric emission limitation for cell rooms; (2) the 

decision to make the promulgated work practices optional for 

sources that choose to undertake continuous monitoring; (3) the 

decision to not require existing facilities to convert to a 

mercury-free chlorine manufacturing process; (4) the elimination 

of the previously applicable part 61 rule’s 2,300 grams/day 

plant-wide emission limitation; and (5) the decision to create a 

subcategory of mercury cell chlor-alkali plants within the 

chlorine production category. On the same day as the 

administrative petition, NRDC and the Sierra Club also filed a 

petition for judicial review of the 2003 Mercury Cell MACT in 

the U.S. Court of Appeals for the D.C. Circuit (Civ. No. 04-

1048). 

By a letter dated April 8, 2004, Jeffrey Holmstead, thenEPA Assistant Administrator for the Office of Air and Radiation, 

notified the NRDC that EPA had granted NRDC’s petition for 

reconsideration of the 2003 Mercury Cell MACT. On July 20, 

2004, the Court granted EPA’s motion to hold the case for 

judicial review in abeyance pending EPA’s action on the 

reconsideration of the 2003 Mercury Cell MACT. On June 11, 2008 

(73 FR 33257), EPA proposed amendments in response to NRDC’s 

petition for reconsideration. Comments received on the 2008 

proposed amendments were reviewed and considered by EPA.
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One commenter provided detailed comments on our proposed 

decision to not require existing facilities to convert to a 

mercury-free chlorine manufacturing process. In addition to

comments on the EPA cost analysis described in our 2008 

proposal, the commenter provided a report to support its 

comments. We reviewed these comments, examined the commenter’s 

report, and concluded that our cost analysis could be improved. 

Therefore, we incorporated some aspects of the commenter’s cost 

analysis, and gathered additional cost information. In 

addition, we considered the policy and legal comments made by 

the commenter regarding the benefits of nonmercury technology to 

produce chlorine. Today’s notice summarizes the comments 

received on these issues, along with this supplemental proposal 

that reflects our consideration of these comments.

There is also U.S. legislation, both recently enacted and 

proposed, that has or will have an impact on these mercury 

chlor-alkali facilities. On October 14, 2008, President Bush 

signed the Mercury Export Ban Act of 2008 into law. This law 

bans U.S. export of elemental mercury (effective in 2013), 

requires the Department of Energy (DOE) to designate and manage 

a long-term storage facility for elemental mercury, and 

prohibits the transfer of elemental mercury by federal agencies.

Both houses of Congress are currently considering 

legislation that, if enacted, would affect this industry (S.1428 
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and H.R. 2190). These bills would amend the Toxic Substances 

Control Act to prohibit the use of mercury at chlor-alkali 

facilities. The House bill would require the facilities to 

cease using mercury by 2013 if the plant chooses to close or by 

2015 if the plant chooses to convert to nonmercury. If this 

legislation passes Congress and is signed by the President into

law, we will evaluate the appropriate action for EPA in light of 

the scope and impact of the law.

III. Summary of Proposed Amendments

A. What are the proposed amendments?

Today we are proposing to amend the 2003 Mercury Cell MACT 

by prohibiting mercury emissions from existing mercury cell 

chlor-alkali plants. This would make the standard for existing 

sources the same as the current standard for new and 

reconstructed sources, which is codified at 40 CFR 

63.8190(a)(1). Since we believe it is impossible to operate a 

mercury cell chlor-alkali plant with zero mercury emissions, 

this proposal would effectively require existing mercury cell 

chlor-alkali plants either to convert to a nonmercury technology 

or to cease production of chlorine with their current mercury 

cell production methods. If promulgated, this supplemental 

proposed rule would eliminate approximately 640 pounds of annual 

mercury emissions, and result in reduced energy demand of around 
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350,000 megawatt hours per year, which is approximately 

equivalent to the energy produced by a 40 megawatt power plant. 

The proposed rule would provide a three-year period from 

the date the final rule is published in the Federal Register to 

achieve zero mercury emissions from mercury cell chlor-alkali 

manufacturing and from mercury recovery units. To demonstrate 

compliance, each owner or operator would have to submit a report 

certifying that all mercury-emitting processes have ceased 

operation permanently. This report would have to be submitted 

no later than 120 days following the applicable compliance date.

In addition, this proposed action would amend the 

provisions of the existing NESHAP that apply to periods of 

startup, shutdown, and malfunction. The revisions of these 

provisions is the result of a Court decision that invalidated 

certain regulations related to startup, shutdown, and 

malfunction in the General Provisions of 40 CFR part 63 (Sierra 

Club v. EPA, 551 F. 3d 1019 (D.C. Cir. 2008)). Consequently, 

the proposed revised rule would require that affected sources 

comply with the emission limitations and work practices at all 

times, including during periods of startup, shutdown, and 

malfunction. These changes would go into effect upon the 

effective date of promulgation of the final rule.

Finally, this proposed rule would correct errors and 

improve the compliance provisions of the rule. These changes, 
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which are described below, were included in the June 2008 

proposal (73 FR 33275).

• The detection limit for continuous mercury monitor analyzers

would be changed to a capability to detect a mercury 

concentration at or below 0.5 times the mercury concentration 

measured during the test or 0.1 μg/m3; and 

• The frequency of determining continuous compliance with the 

emissions standard for mercury recovery units would be 

corrected to specify a daily average (rather than hourly) in

paragraph (b) of §63.8246 “How do I demonstrate continuous 

compliance with the emission limitations and work practice 

standards?” in the 2003 Mercury Cell MACT.

B. How do these proposed amendments relate to the amendments 

proposed on June 11, 2008?

On June 11, 2008 (73 FR 33257), we published the results of 

our reconsideration of the 2003 Mercury Cell MACT. One result 

of this re-consideration was that we proposed modifications to 

the work practice standards that apply to fugitive emissions, 

primarily those fugitive emissions from cell rooms. The 

proposed modifications to these work practices included 

requiring mercury monitoring in the cell room for all

facilities, along with daily work practices, with weekly 

certification of the performance of these work practices. 

Establishment of the “action level” for investigating and 
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correcting high mercury concentration levels revealed by the 

continuous monitors would be done for a minimum of 14 days and 

up to 30 days, at least every six months, and the action level

would be set at the 90th percentile of the data acquired during 

the re-setting time period(s). We also proposed to require 

mercury thermal recovery units that continue to operate at 

closed or converted plants to remain subject to the applicable 

requirements as long as they are in operation. Finally, we 

proposed to correct typographical errors and to make technical 

corrections in the rule related to the compliance requirements.

Five comments were received on the proposed amendments. 

These commenters represent one environmental organization, one 

industry trade organization, and two companies that own and 

operate mercury cell chlor-alkali plants. The fifth comment was 

anonymously submitted in support of environmental organizations.

We have reviewed and considered these comments. As 

discussed in section IV of this preamble, the consideration of 

one of the issues raised in the comments has caused us to 

publish this supplemental proposal today.

If, after consideration of comments on this proposal, we 

decide to promulgate the amendments proposed in today’s notice 

prohibiting mercury emissions, we would not finalize the 

amendments proposed on June 11, 2008, related to cell room 

operation, since the 2008 proposed amendments presupposed that 
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mercury cell chlorine production processes would continue to be 

permitted to emit mercury and would become moot if we promulgate 

today’s proposed amendments. As noted above, two minor 

amendments which were proposed on June 11, 2008, are repeated in 

this proposal. In addition, amendments are being proposed 

related to the requirements which apply during startup, 

shutdown, and malfunction events. If comments received on this 

proposal result in the withdrawal of the proposed prohibition of 

mercury emissions, we then might promulgate the amendments to 

the rule proposed on June 11, 2008, and may incorporate

additional changes to the rule based on public comments. We may 

also promulgate the amendments proposed today related to 

startup, shutdown, and malfunction, even if this proposal is 

withdrawn.

IV. Rationale for Proposed Amendments

A. What is the basis for the proposed zero mercury standard?

1. Technical information and analyses.

a. Background on the 2008 proposal and costs analysis

Section 112(d)(2) of the CAA provides that emission 

standards for new or existing sources of hazardous air 

pollutants (HAP) shall require the maximum degree of reduction 

in emissions (including a prohibition on such emissions, where 

achievable) that EPA, taking into consideration the cost of 

achieving such emission reduction, and any non-air quality 
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health and environmental impacts and energy requirements, 

determines is achievable through application of measures, 

processes, methods, systems or techniques. These may include, 

but are not limited to, measures which (A) reduce the volume of 

or eliminate emissions through process changes, substitution of 

materials or other modifications; (B) enclose systems or 

processes to eliminate emissions; (C) collect, capture or treat 

such pollutants when released from a process, stack, storage or 

fugitive emission point; (D) are design, equipment, work 

practice, or operational standards; or (E) are a combination of 

the above. 

One of the claims presented in NRDC’s petition for 

reconsideration of the 2003 Mercury Cell MACT was that EPA had 

not adequately considered nonmercury technology as a “beyondthe-floor” MACT control measure for existing sources in the 

original rulemaking for the Mercury Cell MACT. Further, NRDC 

claimed that the cost-effectiveness of such a requirement, in 

terms of the annualized costs of control per pound of mercury 

eliminated, would be less than the $9,000 per pound of mercury 

emission reduction that EPA indicated was warranted for mercury 

emissions from this source category in the original 2002 

proposal (67 FR 44683, July 3, 2002). 

In response to this comment, we performed an analysis in 

2008 to determine the capital and annual costs of requiring 
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nonmercury technology (Docket Item EPA-HQ-OAR-2002-0017-0088), 

as a beyond-the-floor MACT control determination. Specifically, 

this analysis estimated the costs and the cost-effectiveness of 

converting the existing mercury cell chlor-alkali plants to 

membrane cells. 

In a chlor-alkali process, an electric current is passed 

through a salt solution or brine (sodium chloride or potassium 

chloride), causing the dissociation of salt to produce chlorine 

gas and an alkaline solution (sodium hydroxide or potassium 

hydroxide). Hydrogen gas is also produced as a by-product. 

This dissociation occurs in chlor-alkali “cells,” where the 

chloride ions stripped from the brine flow to the anode to form 

the chlorine product, and the sodium/potassium ions flow to the 

cathode, where they form the hydroxide product and hydrogen. In 

a mercury cell, the cathode is a flowing layer of liquid 

mercury. The sodium/potassium ions form an amalgam with the 

mercury, which is routed to a decomposer. In the decomposer, 

the amalgam is reacted with water to form the hydroxide product 

and hydrogen. The mercury is then recycled. In the membrane 

process, the chloride ions (at the anode) and the hydrogen (at 

the cathode) are kept apart by a selective polymer membrane that 

allows the sodium ions to pass into the cathodic compartment and 

react to form the hydroxide.
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Conversion from mercury cells to membrane cells is 

technically possible at all existing mercury cell chlor-alkali 

plants, although the amount of significant changes will vary for 

each individual situation. There are parts of the mercury cell 

plant that could be re-used after conversion to the membrane 

cells. It could be possible to use the existing cell room 

building for the new membrane cells, provided that the building 

is in good condition. However, constructing a new membrane cell 

room building would reduce the production losses as the mercury 

cells could continue to operate longer throughout the conversion 

process. Other equipment and processes that possibly could be 

retained include the rectifiers, the hydrogen treatment system, 

and the chlorine compression and liquefaction process.

Obviously, the mercury cells themselves (and associated 

decomposers) would have to be replaced by membrane cells. 

Membrane cells need purer brine than mercury cells, so a 

completely new brine purification system would likely be needed. 

Other equipment that would commonly need to be totally replaced

include the sodium/potassium hydroxide concentration unit and 

evaporation system, the chlorine gas drying and chlorine gas 

absorption units, the power supply unit (excluding the 

rectifiers), pumps, instruments, and much of the piping.

In performing the cost analysis, we used data from readilyavailable sources of information. In our 2008 proposal, we 
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estimated that the average cost-effectiveness associated with 

conversion to nonmercury technology would be approximately 

$14,000 per pound of mercury emissions eliminated, as opposed to 

$9,000 per pound. Further, our 2008 analysis predicted the 

average capital cost of conversion for one mercury cell chloralkali facility in the U.S. to be approximately $68 million per 

plant. The average annualized facility costs for this 

conversion were estimated to be approximately $7.5 million per 

plant. Nationwide, the capital cost was estimated to be nearly 

$340 million and the annual costs around $38 million for the 

five facilities in operation at the time. We estimated that 

this cost impact would be approximately 11 percent of revenues. 

As a result of these analyses, we proposed in 2008 to reject 

conversion to nonmercury technology as a beyond-the-floor 

control requirement.

b. Summary of comments received on 2008 cost analysis

One environmental commenter disagreed with both our 

technical analysis and resulting conclusions in the 2008 

proposal, and claimed that the switch to nonmercury technology 

would be economical. The commenter maintained that conversion

could save millions of dollars annually per plant, with the 

majority of these savings being related to energy costs alone. 

The commenter argued that our 2008 proposal failed to recognize 

or take advantage of these savings, instead allowing a small 
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number of plants to operate to the end of their useful lives 

while emitting mercury into the environment.

The commenter said that EPA considered only the costs 

associated with the conversion, without considering the net cost 

or economic benefit. The commenter maintained that it is likely 

that any plant that converts will experience substantial 

benefits, including an increase in energy efficiency between 25 

and 35 percent per ton of chlorine produced. The commenter 

claimed that this increased energy efficiency could amount to 

savings of more than $98.6 million over five years. 

Furthermore, the commenter pointed out that membrane cells are 

smaller than mercury cells, which would allow plants to increase 

their chlorine capacity as much as 25 percent, leading to 

increased sales and additional energy savings due to the 

additional capacity. The commenter submitted a report that it 

prepared which provided individualized cost analyses for each of 

the remaining mercury cell chlor-alkali plants (Docket Item EPAHQ-OAR-2002-0017-0094.3). According to the commenter, its 

report proves that conversion would pay for the majority of its 

cost in five years. Thus, the commenter concluded that EPA’s 

proposal was incorrect to suppose a “high cost impact” of 

conversion to nonmercury technology, and claimed that EPA should 

heed the evidence that conversion is not only economically 
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feasible but beneficial and mandate conversion to nonmercury

technology as a beyond-the-floor control requirement.

c. Revised 2009 cost analyses

In the second quarter of 2009, in anticipation of this 

supplemental proposal, we performed a revised beyond-the-floor 

cost analysis to address comments received on the 2008 proposed 

amendments described above. While we agree with many of the 

comments in favor of a conversion to mercury-free technology,

the impacts, particularly the savings and benefits, of a forced 

conversion to membrane cells might not be universally applicable

since the conditions and benefits are not the same at every 

facility. We do agree, however, that these facilities would 

achieve some savings associated with lower electricity and the 

elimination of environmental compliance costs for water 

treatment, waste disposal, and mercury monitoring, and that 

these items should be added to the EPA cost analyses. 

Therefore, without assuming that a uniform energy savings would 

accrue to every facility currently operating, we updated our 

analysis to consider the energy costs savings. We also amended 

our analysis to include savings from the elimination of waste 

treatment, waste disposal, and mercury monitoring. On June 5, 

2009, we developed a revised and updated analysis of conversion 

costs for the industry. This analysis was posted as a 
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memorandum in the docket (Docket Item EPA-HQ-OAR-2002-0017-

0098). 

Subsequent to the posting of the June 5, 2009, memorandum, 

industry representatives provided comments on the revised 

analysis (Docket Items EPA-HQ-OAR-2002-0017-0100, 0101, 0102, 

and 0103). One of the major comments raised by industry 

representatives on our revised analysis regarded the 2006 

mercury emission levels used to estimate the cost-effectiveness 

of conversion to nonmercury technology. The industry 

representatives stated that these data were considerably higher 

than their more recently reported emissions. In addition, the 

industry representatives stated that the capital and annual 

costs in our 2008 analysis were underestimated. The industry 

representatives also believed that the annual energy savings 

were overstated because these savings did not take into account 

the additional energy and fuel that would be needed to 

concentrate the caustic by-product obtained using membrane 

cells, which is produced at 33 percent purity, to the 50 percent 

purity obtained using the mercury cell process. The industry 

representatives also commented that the June 2009 cost analysis:

(1) underestimated the mercury storage costs; (2) used an 

interest rate that was in practicality too low for calculating

the capital recovery factor; (3) erroneously used information 

from a European study to estimate the savings due to the 
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elimination of the mercury process that were not applicable to 

the U.S.; and (4) did not consider decommissioning costs.

Consequently, we considered the industry comments and, in 

instances where specific relevant data were provided or 

available, we incorporated the information into another revised 

cost analysis dated September 15, 2009, which was placed in the 

docket (Docket Item EPA-HQ-OAR-2002-0017-0105). The September 

2009 updated cost analysis for conversion to membrane technology 

estimated that the costs to convert the four remaining mercury 

cell plants to be nearly $336 million in total capital costs and 

almost $36 million per year in total annual costs, considering 

electricity and other savings. The cost-effectiveness of 

conversion based on this September 2009 analysis was about 

$66,000 per pound of mercury. 

In this analysis, we did not add certain highly variable 

costs mentioned by the industry commenter that the commenter 

stated could potentially be incurred by a plant when making a 

change to nonmercury technology. These variable costs include 

losses in production, building replacement, plant 

decommissioning, and many others that are likely to be highly 

variable from facility to facility. We believe that the 

magnitude of these costs, although very likely to occur for most 

facilities, would depend on factors such as the condition of the 

existing buildings, available space on the facility site to 
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erect a new cell room building to avoid production losses, and 

possibly other unknown factors. We also received comments from 

an environmental group on the revised 2009 cost analyses. The

complete comments can be found in the docket (Docket EPA-HQ-OAR2002-0017). The commenter stated that the capital costs 

estimated by EPA are too high and the EPA analysis does not 

uniformly account for expansion during conversion. In addition, 

the commenter stated that the regression formula of cost vs. 

capacity used to establish an equation is incorrect since there 

is no relationship between capital costs and capacity when 

considering the full set of relevant data rather than just 

recent U.S. facilities. Also, the commenter stated that the 

capital costs should be annualized over a longer period than the 

15 years used in the analysis since 30 years is a more likely 

useful life.

The commenter also made the following points: the energy 

savings estimated by EPA are too low, since higher reductions in 

electricity consumption are common place; the EPA cost estimate 

for producing steam double-counted the cost associated with 

concentrating caustic and did not account for the fact the steam 

could be obtained on-site without expense; the cost savings for 

environmental compliance avoided are underestimated; and the 

decommissioning costs are already included in estimates of 
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conversion since many factories include the cost of dismantling 

and decommission in the reported cost of conversion.

In addition, the commenter recommended that in evaluating 

the costs, EPA should use the average sales per establishment 

instead of the average sales per ton of chlorine capacity 

because the commenter believes that the latter term grossly 

underestimates sales. The commenter also stated that societal 

costs of conversion to nonmercury technology could result in a 

savings of $4.6 billion in economic productivity and, within 30 

years, could result in an average of $28 million in societal 

benefits from each facility. The commenter also believed that 

the industry-supplied emission estimates are not reliable and 

are likely underestimated, thus overestimating the costs per 

pound of mercury emissions prevented. 

Finally, the commenter stated that EPA’s overall conclusion 

does not reflect the real world since over 100 plants have made 

the conversion globally and at least five chlor-alkali 

facilities expected or received a complete repayment from their 

investment within five years.

d. Cost Analysis for Supplemental Proposal

Many of the comments we received on the September 2009 cost 

analysis were considered and used to estimate costs that 

represent the outcome of a potential conversion to nonmercury 

technology. The estimated costs for this proposed rule, 
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assuming that all four currently operating mercury cell chloralkali plants convert to membrane cell technology, include total 

U.S. capital costs of approximately $300 million dollars, with 

individual plant capital costs ranging from a low of $28 million 

to a high of approximately $160 million. Our analysis does show 

that, in the hypothetical situation that a single plant could

incur the lowest possible costs while also realizing the highest 

possible energy and other savings, there could be an overall 

cost savings in the conversion from mercury cells to membrane 

cells. However, we do not believe that this scenario is 

realistic. Using more conservative assumptions, our best 

estimate is that the average annual costs would be between 

$800,000 and $6.6 million per year per plant. The total U.S. 

annual costs are estimated to be $13 million per year. Based on 

these costs and the estimated mercury emissions for each 

facility, the cost-effectiveness, in terms of annualized costs 

per pound of mercury eliminated, is approximately $20,000 per 

pound for the industry, with a range of around $13,000 to 

$31,000 per pound for the individual facilities. This is within 

the range of cost-effectiveness impacts that we have previously 

found to be reasonable.

In addition to cost analyses, we also conducted an economic 

analysis of the impacts of the zero mercury beyond-the-floor 

option. An impact analysis that compared annual costs to sales 
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showed that the one small entity’s cost-to-sales ratio (CSR) 

would range from 1 to 2 percent, which suggests a significant 

economic impact. The CSRs for the three other parent companies 

are below 1 percent. A profitability effects analysis suggested 

that the conversion costs could reduce the margins by 10 to 20 

percent. Each of the four facilities could elect to close 

rather than convert to nonmercury technology. Since 2003, six 

mercury cell facilities have ceased operation. Three of these 

plants have elected to close, and three have elected to convert. 

Although EPA does not have sufficient data to definitively 

determine whether individual companies would choose to convert 

or close the affected plants, the data suggest that plant 

closure may be the owner’s preferred alternative to meet the 

requirements of the proposed rule. If all four plants elected 

to close rather than convert, we estimate that over 1,000 jobs 

providing over $50 million in wages could be directly affected 

by closure of all four plants. Details of the economic analysis 

are discussed below in section V.A.2

e. Effects of mercury

Mercury is a naturally occurring element that is found in 

air, water, and soil in various forms. In general, industrial 

sources emit different combinations of three different species: 

elemental mercury, inorganic mercury compounds (e.g., mercuric 

chloride), and particulate mercury. The deposition of these 
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emissions could, under circumstances described below, lead to 

formation of an organic form, methylmercury. 

The majority of mercury emitted from mercury cell chloralkali plants is elemental, with a small fraction being 

inorganic mercury.

In general, for elemental mercury, inhalation is the 

primary direct exposure route of potential concern. Effects on 

the nervous system appear to be the most sensitive toxicological 

endpoint and can include tremors, nervousness, insomnia, 

neuromuscular changes (such as weakness, muscle atrophy, and 

muscle twitching), headaches, polyneuropathy, and memory loss. 

In general, for inorganic mercury compounds, both 

inhalation and ingestion exposure routes are of potential 

interest. Effects associated with high exposures to inorganic 

mercury compounds include damage to the gastrointestinal tract, 

the nervous system, and the kidneys. The most sensitive general 

systemic adverse effect due to exposure to inorganic mercury 

compounds is the formation of autoimmune glomerulonephritis 

(that is, inflammation of the kidney). Specific symptoms of 

high exposures to inorganic mercury can include skin rashes and 

dermatitis; mood swings; memory loss; mental disturbances; and 

muscle weakness. 

Mercury that is emitted can be atmospherically transported 

different distances depending on the species. While inorganic 
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mercury is generally transported relatively short distances 

before depositing, elemental mercury, barring any topographical 

interferences, can enter the global pool and remain in 

circulation up to 12 months prior to deposition. Once 

deposited, natural processes, particularly in water bodies, can 

transform some of the mercury into methylmercury, which is a 

highly toxic, more bioavailable form that bioaccumulates in 

organisms and then biomagnifies in the aquatic food chain (such 

as in fish). Thus, the ingestion route via fish consumption 

dominates the pathway for human and wildlife exposure to 

methylmercury. Symptoms of methylmercury poisoning may include:

impairment of the peripheral vision; disturbances in sensations; 

lack of coordination of movements; impairment of speech, 

hearing, walking; and muscle weakness. In general, while adults

can experience effects from high ingestion exposure to 

methylmercury, exposures to developing fetuses, infants, and 

children can pose the highest concerns. For fetuses, infants, 

and children, the primary health effect of methylmercury is 

impaired neurological development. Methylmercury exposure in the 

womb can adversely affect a baby's growing brain and nervous 

system. Impacts on cognitive thinking, memory, attention, 

language, and fine motor and visual spatial skills, all of which 

can result in learning disabilities, have been seen in children 

exposed to methylmercury.
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In general, avoidance of any potential for these severe 

health effects can result from reducing the amount of mercury 

released to the air, water, and other media. The four existing 

mercury cell chlor-alkali plants emit around 640 pounds of

mercury each year to the air, based on recent estimates. They 

also release a total of just under 1 ton of mercury per year to 

other media, including around 50 pounds per year to water. The 

proposed amendments would result in the elimination of these 

releases in the future, and therefore could have beneficial nonair quality health and environmental impacts.

In addition, mercury cell chlor-alkali plants are commonly 

identified as contaminated sites and designated for correction 

action under the EPA Superfund or Resource Conservation and 

Recovery Act (RCRA) corrective action programs. In fact, three 

of the four currently operating mercury cell plants have been

identified under the RCRA corrective action program. The 

shutdown of the mercury cell processes would accelerate the 

clean-up of these sites, again resulting in beneficial non-air 

quality health and environmental impacts.

2. Rationale for selection of the zero mercury standard

While the results of these additional analyses were that 

the costs and cost-effectiveness values decreased from those 

estimated in our 2008 analysis, there is still some uncertainty 

regarding numerous facets of the cost analysis. Since the lower
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estimates of potential costs show that conversion to nonmercury 

technology may be a reasonable investment action in the long 

term, we are proposing this supplemental amendment to request a 

complete set of comments on the costs presented here in order to 

prepare a final cost analysis to support or not support a 

standard for zero mercury emissions. Once all comments are 

received, we will re-evaluate whether or not these costs 

constitute an unreasonably high cost impact given the benefits 

of zero mercury emissions to public health, the environment, and 

to energy use. 

We gave serious consideration to the comments we received 

that stated the use of mercury in chlor-alkali plants is 

unnecessary since over 95 percent of the chlorine produced in 

the U.S. is already produced using mercury-free technology. 

Forcing these plants to switch to mercury-free technology would 

eliminate the approximately 0.5 tons of mercury released per 

year.

In the 2008 proposal, we rejected the conversion to 

nonmercury technology as a beyond-the floor option because of 

the high cost impacts. The total annual costs estimated at that 

time were around $38 million, or around $7.5 million per 

facility on average for each of the five facilities operating at 

that time. The revised cost analysis described above estimates 

total annual costs of around $13 million, which averages to just 
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over $3 million per facility. Therefore, the current estimated 

conversion costs are around 60 percent lower than those driving 

our decision in 2008. 

With regard to cost-effectiveness, we stated in the 

original proposal of the Mercury Cell MACT Standard in 2002 (67 

FR 44683) that we considered the additional mercury emission 

reduction achieved by the beyond-the-floor option for hydrogen 

by-product vents and end-box ventilation systems to be warranted 

at an incremental cost-effectiveness of $9,000 per pound of 

mercury emission reduction. We did not indicate that this costeffectiveness level represented an upper end of acceptability, 

and in other contexts, such as the Clean Air Mercury Rule (70 

Federal Register 28606, 05/18/2005),a

 

a On March 29, 2005, EPA published a final rule ( 70 FR 15994 ) 

entitled ‘‘Revision of December 2000 Regulatory Finding on the 

Emissions of Hazardous Air Pollutants From Electric Utility 

Steam Generating Units and the Removal of Coal- and Oil-Fired 

Electric Utility Steam Generating Units from the Section 112(c) 

List (Section 112(n) Revision Rule).” Following that final 

action, the Administrator received two petitions for 

reconsideration. In response to those petitions, EPA announced 

(Federal Register, Vol. 70, October 28, 2005, p. 62200) the 

reconsideration of certain aspects of the Section 112(n) 

Revision Rule, but these aspects did not include costs related 

to mercury control or cost-effectiveness. 

we have found even larger 

cost-effectiveness factors to be reasonable. Similarly, in our 

2008 proposal of amendments, we did not conclude that a costeffectiveness value of $14,000 per pound of mercury emission 

reduction was unacceptable, as this was one of several cost and 
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economic factors considered that led to our conclusion regarding 

the high cost impact of the beyond-the-floor option of forced 

conversion. 

Historically, EPA has not established a clear costeffectiveness level for mercury reductions that are considered

acceptable. In fact, we have rejected regulatory alternatives 

for mercury with cost-effectiveness values of $5,000 per pound, 

and accepted regulatory strategies with estimated costeffectiveness values of $39,000 per pound, in the case of the 

Clean Air Mercury Rule.b

We also recognize that the mercury cell technology is an 

outdated technology that has been largely phased out in the U.S. 

even without a zero mercury emissions requirement and even with 

the high costs of the conversion process. While the economic 

analysis suggests significant adverse economic impacts could 

 Obviously, when making decisions 

regarding regulatory approaches to achieve mercury reductions, 

we have looked at cost in conjunction with many other factors to 

assess the reasonableness of possible control strategies.

 

b The costs of complying with CAMR as a whole are discussed 

briefly in the preamble to the final rule [Federal Register, 

Vol. 70, No. 95, May 18, 2005, pp. 28606 -28700. Standards of 

Performance for New and Existing Stationary Sources: Electric 

Utility Steam Generating Units (40 CFR Parts 60, 72, and 75)], 

and in more detail in two items in the two air dockets for the 

CAMR rule: EPA Office of Research and Development’s White 

Papers ‘‘Control of Mercury Emissions from Coal Fired Electric 

Utility Boilers." Docket ID No. OAR–2002–0056 and Docket ID No. 

A–92–55. 
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occur if all four plants closed rather than convert to 

nonmercury technology, we believe that it is possible that one 

potential outcome of this proposed rule is that some companies 

will convert rather than close, if the recent incidence of 

conversion to nonmercury technology by the U.S. chlor-alkali 

industry continues. Therefore, the negative economic effects 

described above would be mitigated if only some of the four 

facilities closed.

We also believe that any near-term negative economic 

impacts are justified given the potential adverse health and 

environmental effects of mercury that will be reduced 

permanently into the future. Therefore, we are proposing this 

amendment to request comments on whether the benefits of 

achieving zero mercury emissions from this industry, as a 

beyond-the-floor control alternative, are warranted given the 

foregoing discussion.

B. What is the basis for the proposed rule changes related to 

startup, shutdown, and malfunction?

The United States Court of Appeals for the District of 

Columbia Circuit vacated portions of two provisions in EPA’s CAA 

Section 112 General Provisions regulations governing the 

emissions of HAP during periods of startup, shutdown, and 

malfunction (SSM). Sierra Club v. EPA, 551 F.3d 1019 (D.C. Cir. 

2008). Specifically, the Court vacated the SSM exemption in 40 
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CFR 63.6(f)(1) and 40 CFR 63.6(h)(1). When incorporated into 

CAA Section 112(d) regulations for specific source categories, 

these two provisions exempted sources from the requirement to 

comply with the otherwise applicable CAA section 112(d) emission 

standard during periods of SSM. The 2003 Mercury Cell MACT 

Subpart included a reference to 40 CFR 63.6(f)(1), as well as 

regulatory text unique to the 2003 Mercury Cell MACT that 

exempted compliance with standards during SSM events. It did 

not include a reference to 40 CFR 63.6 (h)(1), since the rule 

does not have opacity and visible emission standards. In light 

of Sierra Club v. EPA, we are proposing to revise Table 10, 

which addresses the applicability of the Part 63 General 

Provisions to mercury cell chlor-alkali plants, to state that 40 

CFR 63.6(f)(1) does not apply. As such, all emission standards 

and work practices would apply at all times. We are also 

proposing to remove other references in subpart IIIII and Table 

10 related to SSM, including provisions that exempted compliance 

with standards during SSM periods. First, regarding the 

references to the vacated portions of the General Provisions, 

EPA believes that deleting those references is a ministerial 

action that is compelled by the Court’s 2008 ruling in Sierra 

Club. Regarding the provisions in the 2003 Mercury Cell MACT 

that independently (without merely referring to the vacated 

portions of the General Provisions) exempt compliance during SSM 
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periods, EPA does not believe it is appropriate to propose rule 

revisions that leave in place existing provisions that are 

inconsistent with the decision of the D.C. Circuit. Regarding 

startup and shutdown modes of operation at mercury cell plants, 

EPA does not consider emissions during these periods to be 

significantly different than emissions during normal operation, 

and therefore is not proposing separate limits that would apply 

during these periods. We do not have any information that shows 

emissions at mercury cell plants would be significantly 

different during startup or shutdown than during normal 

operation. Nor do we have information suggesting that the 

emissions control measures required by the 2003 rule would be 

less effective during startup or shutdown periods. 

In addition, EPA does not view malfunction as a distinct 

operating mode and, therefore, any emissions that occur at such 

times do not need to be taken into account in setting CAA 

section 112(d) standards. Malfunctions are distinguishable from 

startup, shutdown and normal operations, which are all 

predictable and routine aspects of a source’s operations. By 

contrast, malfunction is defined as a “sudden, infrequent, and 

not reasonably preventable failure of air pollution control and 

monitoring equipment, process equipment, or a process to operate 

in a normal or useful manner [. . .]” (40 CFR 63.2). We note 

that CAA section 112 uses the concept of “best performing” 
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sources to define MACT, the level of stringency that major 

source standards must meet. It is reasonable to interpret 

section 112(d) as not requiring EPA to account for malfunctions 

in setting emission standards. Applying the concept of “best 

performing” to a source that is malfunctioning presents 

difficulties. The goal of best performing sources is to avoid 

malfunctions of their units. Consequently, MACT should not be 

based on periods in which there is a failure to operate. 

Moreover, even if malfunctions were considered a distinct 

operating mode, we believe it would be impracticable to take 

into account malfunctions in setting CAA section 112(d) 

standards. As noted above, malfunctions are sudden and 

unexpected events, and it would be difficult to set a standard 

that takes into account the myriad different types of 

malfunctions that can occur across all sources. Moreover, 

malfunctions can vary in frequency, degree, and duration, 

further complicating standard setting. 

This approach will encourage shutdowns as soon as 

practicable when a malfunction that affects emissions occurs. 

In the event that a source fails to comply with the applicable 

CAA section 112(d) standards as a result of a malfunction event, 

EPA would determine an appropriate response based on, among 

other things, the good faith efforts of the source to minimize 

emissions during malfunction periods, including preventative and 
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corrective actions, as well as root cause analyses to ascertain 

and rectify excess emissions. EPA would also consider whether 

the source’s failure to comply with the CAA section 112(d) 

standard was, in fact, “sudden, infrequent, not reasonably 

preventable” and was not instead “caused in part by poor 

maintenance or careless operation.” 40 CFR 63.2 (definition of 

malfunction). 

C. What is the basis for the proposed rule corrections?

1. Detection limit for mercury monitor analyzers. 

Paragraph (a)(2) of §63.8242, “What are the installation, 

operation, and maintenance requirements for my continuous 

monitoring systems?” requires that mercury continuous monitor 

analyzers 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. Since 

promulgation of the 2003 Mercury Cell MACT, we determined that 

setting the analyzer detection capability in reference to the 

concentration level during the performance test could be

problematic. We realized that a concentration of 0.5 times the 

mercury concentration could, in cases of low mercury 

concentrations, be infeasible for the monitoring devices on the 

market. Information available to us at this time shows that 0.1 

μg/m3 is the detection limit of commonly commercially available 

analyzers. We believe that analyzers with detection limits at 
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this level are more than sufficient to determine compliance with 

the limitations in the 2003 Mercury Cell MACT. Therefore, we 

are proposing to revise this paragraph to require a detector 

with the capability to detect a mercury concentration at or 

below 0.5 times the mercury concentration measured during the 

test or 0.1 μg/m3.

2. Averaging period for mercury recovery unit compliance. 

The 2003 Mercury Cell MACT is inconsistent as to whether 

the rule requires a daily average or an hourly average to 

determine continuous compliance with the emissions standard for 

mercury recovery units found at §63.8190(a)(3)of §63.8190 “What 

emission limitations must I meet?” Paragraph (b) of §63.8243 

“What equations and procedures must I use to demonstrate 

continuous compliance?” clearly indicates that this averaging 

period is daily: “you must calculate the daily average mercury 

concentration using Equation 2 . . .” However, paragraph (b) of 

§63.8246 “How do I demonstrate continuous compliance with the 

emission limitations and work practice standards?” states that 

for each mercury thermal recovery unit vent, “you must 

demonstrate continuous compliance with the applicable emission 

limit specified in §63.8190(a)(3) by maintaining the outlet 

mercury hourly-average concentration no higher than the 

applicable limit.”
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It was our intention for compliance to be based on a daily

average, as detailed below, and the inclusion of “hourly” in 

paragraph (b) of §63.8246 “How do I demonstrate continuous 

compliance with the emission limitations and work practice 

standards?” was a drafting error. Therefore, we are proposing 

to correct this error by replacing “hourly” in §63.8246(b) with 

“daily.” In the proposal Federal Register notice for the 2003 

Mercury cell MACT (67 FR 44678, July 3, 2002), we clearly stated 

our intention when we summarized the requirements as follows:

“To continuously comply with the emission limit for 

each by-product hydrogen stream, end-box ventilation system 

vent, and mercury thermal recovery unit, we are proposing 

that each owner and operator would continuously monitor 

outlet elemental mercury concentration and compare the 

daily average results with a mercury concentration 

operating limit for the vent . . . .”

“Continuous compliance would be demonstrated by 

collecting outlet elemental mercury concentration data 

using continuous mercury vapor monitor, calculating daily 

averages, and documenting that the calculated daily average 

values are no higher than established operating limits. 

Each daily average vent elemental mercury concentration 

greater than the established operating limit would be 

considered a deviation. 

D. What is our rationale for doing a supplemental proposal?

The prohibition of mercury emission requirement that we are 

proposing today is a result of comments received on the 

amendments proposed on June 11, 2008. We will examine and 

analyze all comments received on today’s proposal and then we 

will take final action that may either: (1) promulgate today’s 

proposed prohibition of mercury emissions, (2) promulgate the
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amendments proposed on June 11, 2008, or (3) respond to comments 

we receive and promulgate other amendments that are supported by 

the data. However, the compliance errors that we proposed to 

correct in our 2008 amendments likely will be promulgated in 

either pathway since the facilities will need to comply with the 

Mercury Chlor-alkali MACT for at least a few more years even if 

we promulgate a beyond-floor zero mercury standard. The 

amendments to SSM provisions will also likely be promulgated 

under either pathway. We also will likely require mercury 

thermal recovery units that continue to operate at closed or 

converted plants to remain subject to the applicable 

requirements of the Mercury Cell MACT as long as they are in 

operation.

V. Impacts of Proposed Amendments

A. What are the cost and economic impacts of this proposal?

1. Cost Impacts

The estimated costs for the proposed rule, assuming that 

all four currently operating mercury cell chlor-alkali plants 

convert to membrane cell technology, include total U.S. capital 

costs of approximately $300 million dollars, with individual 

plant capital costs ranging from a low of $28 million to a high 

of approximately $160 million. The total U.S. annual costs are 

estimated to be around $13 million per year, ranging from a low 

of $800,000 per plant per year to almost $7 million per plant. 
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Based on these costs and the reported mercury emissions for 2008 

for each facility,c

2. Economic Impacts

the cost-effectiveness, in terms of 

annualized costs per pound of mercury eliminated, is estimated 

to be approximately $20,000 per pound, which is less than the 

$39,000 per pound level we found reasonable in the Clean Air 

Mercury Rule. A memorandum that documents the details of this 

cost analysis can be found in the docket. We are specifically 

requesting comment on our analysis, along with facility-specific 

data, to allow a refinement of the analysis for this proposed 

rule.

An economic impact analysis (EIA) and small business 

screening analysis was performed for this proposed rule that 

would amend the NESHAP to prohibit emissions of mercury from the 

mercury cell chlor-alkali process. A report that documents the 

EIA methods and results can be found in the docket (EPA-HQ-OAR2002-0017). 

Although individual plant information would be the best 

method to assess the true economic impacts of the rule, detailed 

information for this industry was not publicly available. As a 

result, we relied on parent company information provided in 

company annual reports (e.g., form 10-K), local press and 

industry trade publications, and company Web sites. 

 

c

 For the purpose of this analysis, we assumed that the mercury emissions 

from the ASHTA facility were 100 pounds per year.
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There are many aspects of the cost estimate for conversion 

that are unknown or difficult to assess. While we believe that 

we have evaluated the conversion cost information available to 

us at the time of this action, the true costs may vary 

considerably. However, variation in engineering costs is not 

expected to cause a significant difference in the general 

conclusions of the EIA.

We performed an analysis that compared the annual 

conversion costs to sales. We estimated that the CSR of ASHTA, 

the one small business in this industry, would range from one to 

two percent using the costs presented in this proposal. The 

other three plants are owned by large parent companies with 

significant company-wide sales. As a result, the CSRs for these 

large parent companies are below one percent. When single plant 

sales were considered, the CSRs for the mercury cell chloralkali plants owned by large parent companies ranged from 4 to 

9 percent. 

We also analyzed industry profitability effects by 

comparing the annual conversion costs to reported industry 

margins for a representative electrochemical unit (ECU). This 

analysis confirms the results of the sales comparisons that 

plant conversion costs will likely have an economically 

significant effect. Conversion costs could reduce the margins 

by 10 to 20 percent.
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This proposed rule would force owners of mercury chloralkali plants to make an investment decision based on the costs 

of conversion as opposed to the future benefits of the 

conversion. This proposed rule could lead to plant shutdowns 

that would involve adjustment costs for people working at the 

affected plants. Affected plants may also have strong links 

with other firms or downstream markets; as a result, secondary 

consequences of the regulation are important to consider. 

Many owners have converted from mercury cell chlor-alkali 

technologies in Europe and the U.S., while other mercury cell 

chlor-alkali plant owners have concluded the investment decision 

was currently not in their company’s interest given their 

assessment of future economic conditions, and have shutdown 

their mercury cell chlor-alkali plants instead. Since 2003, 

three U.S. mercury cell chlor-alkali facilities have closed and 

three have converted. Specifically, the Occidental Chemical 

mercury cell chlor-alkali facilities in Delaware City, Delaware, 

Muscle Shoals, Alabama, and Deer Park, Texas, have closed; while 

the PPG facility in Lake Charles, Louisiana, the ERCO facility 

in Port Edwards, Wisconsin, and the Pioneer chlor-alkali 

facility (now owned by Olin) in St. Gabriel, Louisiana, have 

converted to membrane cells.

We do not have sufficient data to predict whether 

individual companies would choose to convert or close the 
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affected mercury cell chlor-alkali plants. However, the data 

obtained in this study suggests that plant closure may be a 

preferred alternative to meet the requirements of the proposed 

rule for one or more of the mercury cell chlor-alkali plants. 

If all four plants elected to close rather than convert, 

approximately 1,000 jobs providing over $50 million in wages 

could be directly affected. Whether plants convert or close, 

however, there is the possibility of temporary jobs created for 

the conversion or decommissioning of the plants. 

As noted above, individual plant information was not 

available to perform a refined analysis of whether these mercury 

cell plants would likely convert to nonmercury technology or 

close. We are specifically requesting comment on our analysis, 

along with facility-specific data, to allow a refinement of the 

analysis for this proposed rule.

B. What are the environmental and energy impacts of this 

proposal?

We estimate that the total mercury emissions from the four 

mercury cell operating facilities to be around 640 pounds per 

year. This proposed rule would reduce mercury emissions by this 

amount. These four facilities reported almost 2,000 additional 

pounds of on-site and off-site mercury releases to media other 

than air per year. These releases would be eliminated in the 

longer term, with consequential benefits for non-air quality 
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related health and environmental values. The potential problems 

associated with the handling and continuous management of over 

1,200 tons of virgin mercury that is used in the cells at these 

four chlor-alkali plants would also be eliminated. In addition, 

approximately two tons of this mercury was reported by the 

industry as “unaccounted” in 2008. This proposed rule would 

eliminate the unaccounted mercury as well. 

The membrane cell chlor-alkali process requires less energy 

than the mercury cell process. Therefore, assuming that all 

four existing mercury cell chlor-alkali plants convert to 

membrane cells, there would be a savings in energy. We estimate 

that this savings would be around 350,000 megawatt hours per 

year, which is approximately equivalent to the energy produced 

annually by a 40 megawatt power plant.

In the short term, the conversion of these facilities would 

result in the need to dispose of mercury-contaminated wastes. 

While there is considerable uncertainty in quantifying the 

amount of these wastes, we estimate that there could be around 

7,000 cubic meters of mercury contaminated waste generated that 

could contain around six tons of mercury. 

As stated above, over 1,200 tons of virgin or process 

mercury from the facilities would need to be dealt with whether 

the facilities close or convert to nonmercury technology. The 

Mercury Export Ban Act of 2008, discussed earlier, would 
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prohibit this mercury from being exported. Therefore, this 

mercury would need to be stored or sold domestically. Since 

mercury is a hazardous substance, it cannot be stored without a 

permit; hence, DOE is planning to build a federal facility to 

accommodate the excess mercury that results from the export ban. 

We are specifically requesting comment on our analysis, along 

with any facility-specific data, to allow a refinement of the 

analysis for this proposed rule.

VI. Statutory and Executive Order Reviews

A. Executive Order 12866: Regulatory Planning and Review

This action is a “significant regulatory action” under the 

terms of Executive Order 12866 (58 FR 71735, October 3, 1993)

because it may raise novel legal or policy issues. Accordingly, 

EPA submitted this action to the Office of Management and Budget 

(OMB) for review under EO 12866 and any changes made in response 

to OMB recommendations have been documented in the docket for 

this action.

In addition, EPA prepared an analysis of the potential 

costs and benefits associated with this action. A copy of the 

analysis is available in the docket for this action and the 

analysis is briefly summarized above in section V.A.

B. Paperwork Reduction Act

The information collection requirements in this proposed 

rule, have been submitted for approval to OMB under the 
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Paperwork Reduction Act, 44 U.S.C. 3501 et seq. The information 

collection request (ICR) document prepared by EPA has been 

assigned an EPA ICR number 2046.06.

The OMB has previously approved the information collection 

requirements in the existing regulation (40 CFR 63, subpart 

IIIII) under the provisions of the Paperwork Reduction Act, 44 

U.S.C. 3501 et seq. and has assigned OMB control number 2060-

0542. The OMB control numbers for EPA’s regulations in 40 CFR 

are listed in 40 CFR part 9.

These proposed amendments result in changes to the 

information collection requirements in the regulation. This 

information is being collected to assure that mercury emissions 

have been eliminated. The required notifications, reports, and 

records are essential in determining compliance, and are 

required of all affected facilities. The recordkeeping and 

reporting requirements in this proposed rule are based on the 

requirements in EPA’s NESHAP General Provisions (40 CFR part 63, 

subpart A). The recordkeeping and reporting requirements in the 

General Provisions are mandatory pursuant to section 114 of the 

CAA (42 U.S.C 7414). All information other than emissions data 

submitted to EPA pursuant to the information collection 

requirements for which a claim of confidentiality is made is 

safeguarded according to CAA section 114(c) and the Agency’s 

implementing regulations at 40 CFR part 2, subpart B.
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The only information collection associated with the 

proposed amendments is a one-time certification that must be 

submitted 60 days after the compliance date. It is estimated 

that the burden for this information collection is 3 labor hours 

per response per facility, for a total of 12 labor hours for all 

four facilities. This burden will occur during the first year 

after promulgation, but the annual burden for this information 

collection averaged over the three years following the 

compliance date of these amendments is estimated to be a total 

of 4 labor hours per year. Burden is defined at 5 CFR

1320.3(b).

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 in 40 CFR are listed in 40 CFR 

part 9.

To comment on the Agency’s need for this information, the 

accuracy of the provided burden estimates, and any suggested 

methods for minimizing respondent burden, EPA has established a 

public docket for this action, which includes this ICR, under 

Docket ID number EPA-HQ-OAR-2002-0017. Submit any comments 

related to the ICR for this proposed rules to EPA and OMB. See 

“Addresses” section at the beginning of this notice for where to 

submit comments to EPA. Send comments to OMB at the Office of 
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Information and Regulatory Affairs, Office of Management and 

Budget, 725 17th Street NW, Washington, DC 20503, Attention: 

Desk Office for EPA. Since OMB is required to make a decision 

concerning the ICR between 30 and 60 days after [INSERT DATE OF 

PUBLICATION IN THE FEDERAL REGISTER], a comment to OMB is best 

assured of having its full effect if OMB receives it by [INSERT 

DATE 30 DAYS AFTER PUBLICATION IN THE FEDERAL REGISTER]. The 

final rule will respond to any OMB or public comments on the 

information collection requirements contained in these proposed 

amendments.

C. Regulatory Flexibility Act

The Regulatory Flexibility Act generally requires an agency 

to prepare a regulatory flexibility analysis of any rule subject 

to notice and comment rulemaking requirements under the 

Administrative Procedure Act or any other statute unless the 

agency certifies that the rule would not have a significant 

economic impact on a substantial number of small entities. 

Small entities include small businesses, small not-for-profit 

enterprises, and small governmental jurisdictions. 

For the purposes of assessing the impacts of this proposed 

rule on small entities, small entity is defined as: (1) a small 

business that meets the Small Business Administration size 

standards for small businesses, as defined by the Small Business 

Administration's (SBA) regulations at 13 CFR 121.201; (2) a 
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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 this proposed 

rule on small entities, I certify that this action will not have 

a significant economic impact on a substantial number of small 

entities. This proposed rule is estimated to impact a total of 

four sources, with one of the four facilities estimated to be a 

small entity. We have estimated that small entity compliance 

costs, as assessed by the facilities’ CSR, are expected to be 

just over 1 percent of revenues. New sources are already 

prohibited from using the mercury technology in the chlor-alkali 

production process by virtue of the 2003 Mercury Cell MACT’s 

provisions; consequently, we did not estimate any impacts for 

new sources since this rulemaking would not impose any new 

requirements on them. 

This proposed rule will not have a significant economic 

impact on a substantial number of small entities, since there is 

only one small entity in the group of four facilities and 

compliance costs for this small entity are expected to be just 

over 1 percent of revenues. However, we continue to be 

interested in the potential impacts of this proposed action on 
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small entities and welcome comments on issues related to such 

impacts.

D. Unfunded Mandates Reform Act

This action contains no Federal mandates under the 

regulatory provisions of Title II of the Unfunded Mandates 

Reform Act of 1995 (UMRA), 2 U.S.C. 1531-1538 for State, local, 

or tribal governments or the private sector. The action imposes 

no enforceable duty on any State, local or tribal governments or 

the private sector. (Note: The term “enforceable duty” does not

include duties and conditions in voluntary federal contracts for 

goods and services.) Therefore, this action is not subject to 

the requirements of sections 202 and 205 of the UMRA. This 

action also is not subject to the requirements of section 203 of 

UMRA because it contains no regulatory requirements that might 

significantly or uniquely affect small governments. 

E. Executive Order 13132: Federalism

Executive Order 13132 (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” is 

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 
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distribution of power and responsibilities among the various 

levels of government.” 

This action 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. This proposed rule does not impose any requirements on 

State and local governments. Thus, Executive Order 13132 does 

not apply to this action. 

In the spirit of Executive Order 13132, and consistent with 

EPA policy to promote communications between EPA and State and 

local governments, EPA specifically solicits comment on this 

proposed rule from State and local officials.

F. Executive Order 13175: Consultation and Coordination with 

Indian Tribal Governments

This action does not have tribal implications, as specified 

in Executive Order 13175 (65 FR 67249, November 9, 2000). This 

proposed rule imposes no requirements on tribal governments. 

Thus, Executive Order 13175 does not apply to this rule. EPA 

specifically solicits additional comment on this proposed rule 

from tribal officials.

G. Executive Order 13045: Protection of Children from 

Environmental Health and Safety Risks
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EPA interprets Executive Order 13045 (62 F.R. 19885, April 

23, 1997) as applying to those regulatory actions that concern 

health or safety risks, such that the analysis required under 

section 5-501 of the Order has the potential to influence the 

regulation. This action is not subject to Executive Order 13045 

because it is based solely on technology performance.

H. Executive Order 13211: Actions Concerning Regulations That 

Significantly Affect Energy Supply, Distribution, or Use

This action is not a “significant energy action” as defined 

in Executive Order 13211, “Actions Concerning Regulations That 

Significantly Affect Energy Supply, Distribution, or Use” (66 FR 

28355, May 22, 2001) because it is not likely to have a 

significant adverse effect on the supply, distribution, or use 

of energy. We have concluded that this action is not likely to 

have any adverse energy effects because no additional 

requirements are contained in this proposed rule that consume 

energy.

I. National Technology Transfer and Advancement Act

Section 12(d) of the National Technology Transfer and 

Advancement Act of 1995 (“NTTAA”), Public Law No. 104-113 (15 

U.S.C. 272 note) directs EPA to use voluntary consensus 

standards in its regulatory activities unless to do so would be 

inconsistent with applicable law or otherwise impractical. 

Voluntary consensus standards are technical standards (e.g., 
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materials specifications, test methods, sampling procedures, and 

business practices) that are developed or adopted by voluntary 

consensus standards bodies. NTTAA directs EPA to provide 

Congress, through OMB, explanations when the Agency decides not 

to use available and applicable voluntary consensus standards.

This proposed rulemaking does not involve technical 

standards. Therefore, EPA is not considering the use of any 

voluntary consensus standards.

J. Executive Order 12898: Federal Actions to Address 

Environmental Justice in Minority Populations and Low-Income 

Populations

Executive Order 12898 (59 FR 7629, February 16, 1994) 

establishes Federal executive policy on environmental justice. 

Its main provision directs Federal agencies, to the greatest 

extent practicable and permitted by law, to make environmental 

justice part of their mission by identifying and addressing, as 

appropriate, disproportionately high and adverse human health or 

environmental effects of their programs, policies, and 

activities on minority populations and low-income populations in 

the U.S.

EPA has determined that this proposed rule will not have 

disproportionately high and adverse human health or 

environmental effects on minority or low-income populations 

because it increases the level of environmental protection for 
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all affected populations without having any disproportionately 

high and adverse human health or environmental effects on any 
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National Emission Standards for Hazardous Air Pollutants: 

Mercury Emissions from Mercury Cell Chlor-Alkali Plants

Page 58 of 77

population, including any minority or low-income population. 

The nationwide standards would eliminate mercury emissions and 

thus decrease the amount of emissions to which all affected 

populations are exposed.

List of Subjects in 40 CFR Part 63 

Environmental protection, Air pollution control, Hazardous 

substances, Incorporation by reference, Reporting and 

recordkeeping requirements.

Dated:

Lisa P. Jackson,

Administrator.
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For the reasons set out in the preamble, title 40, chapter I of 

the Code of Federal Regulations is proposed to be amended as 

follows:

PART 63 - [Amended]

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

follows:

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

Subpart IIIII - [Amended]

2. Section 63.8184 is amended by revising paragraphs (a) 

and (c) to read as follows:

§ 63.8184 What parts of my plant does this subpart cover? 

(a) This subpart applies to two types of affected sources 

at a mercury cell chlor-alkali plant: the mercury cell chloralkali production facility, as defined in paragraph (a)(1) of 

this section and § 63.8266; and the mercury recovery facility, 

as defined in paragraph (a)(2) of this section and § 63.8266.

(1) The mercury cell chlor-alkali production facility 

affected source consists 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. 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, 
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caustic systems, and storage areas for mercury-containing 

wastes.

(2) The mercury recovery facility affected source consists

of all processes and associated operations needed for mercury 

recovery of wastes generated from a mercury cell chlor-alkali 

plant. This subpart covers mercury emissions from mercury 

thermal recovery unit vents and fugitive emission sources 

associated with storage areas for mercury-containing wastes.

* * * * *

(c) A mercury recovery facility is a new affected source 

if you commence construction or reconstruction of the affected 

source after the dates specified in § 63.8186(c) and (d). An 

affected source is reconstructed if it meets the definition of a 

reconstruction in § 63.2.

3. Section 63.8186 is revised to read as follows:

§ 63.8186 When do I have to comply with this subpart?

(a) Compliance date for the emission limitations in §

63.8190(a)(2), the work practices in § 63.8192, and all the 

associated requirements for existing mercury cell chlor-alkali 

production facility and mercury recovery facility affected 

sources. If you have an existing mercury cell chlor-alkali 

production facility or mercury recovery facility affected 

source, you must comply with the applicable emission limitations 

in § 63.8190(a)(2), work practices in § 63.8192, and all the 
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associated requirements no later than December 19, 2006.

(b) Compliance date for emission limitation in 

§ 63.8190(b) and all the associated requirements for existing 

mercury cell chlor-alkali production facility and mercury 

recovery facility affected sources. If you have an existing 

mercury cell chlor-alkali production facility or mercury 

recovery facility affected source, you must comply with

§ 63.8190(b) by three years after the date that the final rule 

is published in the Federal Register. Prior to compliance with 

§ 63.8190(b), you must comply with the applicable emission 

limitations in § 63.8190(a)(2), work practices in § 63.8192, and 

all the associated requirements. After you have demonstrated 

compliance with § 63.8190(b) and have submitted the 

certification of compliance in accordance with § 63.8252(f), you 

are only subject to § 63.8246(d) of this subpart.

(c) Compliance date for the emission limitations in 

§ 63.8190(a)(3), the work practices in § 63.8192, and all the 

associated requirements for new or reconstructed mercury 

recovery facility affected sources. If you commenced 

construction or reconstruction of your mercury recovery facility 

after July 3, 2002, and before [INSERT DATE OF PUBLICATION OF 

THIS PROPOSAL IN THE FEDERAL REGISTER], you must comply with the 

applicable emission limitation in § 63.8190(a)(3), work 

practices in § 63.8192, and all the associated requirements by 
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either December 19, 2003, or upon initial startup, whichever is 

later.

(d) Compliance date for the emission limitation under

§ 63.8190(b) and all the associated requirements for new or 

reconstructed mercury recovery facility affected sources.

(1) If you commenced construction or reconstruction of 

your mercury recovery facility after July 3, 2002, and before 

[INSERT DATE OF PUBLICATION OF THIS PROPOSAL IN THE FEDERAL 

REGISTER], you must comply with the emission limitation in §

63.8190(b) and all the associated requirements by three years 

after the date that the final rule is published in the Federal 

Register. Prior to compliance with § 63.8190(b), you must 

comply with the applicable emission limitation in §

63.8190(a)(3), work practices in § 63.8192, and all the 

associated requirements. After you have demonstrated compliance 

with § 63.8190(b) and have submitted the certification of 

compliance in accordance with § 63.8252(f), you are you are only 

subject to § 63.8246(d) of this subpart.

(2) If you commenced construction or reconstruction of 

your mercury recovery facility after [INSERT DATE OF PUBLICATION 

OF THIS PROPOSAL IN THE FEDERAL REGISTER], you must comply with 

the emission limitation in § 63.8190(b) and all the associated 

requirements by the date that the final rule is published in the 

Federal Register, or upon initial startup, whichever is later.
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4. Section 63.8190 is amended as follows:

a. Revising paragraph (a)(2) introductory text; 

b. Revising paragraph (a)(3) introductory text; and

c. Adding paragraph (b);

The revisions read as follows:

§ 63.8190 What emission limitations must I meet?

(a) * * * 

(2) Emission limits which apply to existing mercury cell 

chlor-alkali production facilities prior to achieving compliance 

with § 63.8190(b). 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 § 63.8243(a).

* * * * *

(3) Emission limits which apply to existing mercury 

recovery facilities and to new or reconstructed mercury recovery 

facilities that commenced construction or reconstruction after 

July 3, 2002, and before [INSERT DATE OF PUBLICATION OF THIS 

PROPOSAL IN THE FEDERAL REGISTER] prior to achieving compliance 

with paragraph (b) of this section. 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.

* * * * *

(b) Emission limit which applies to each mercury cell 
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chlor-alkali production facility and each mercury recovery 

facility after the applicable compliance date specified in 

paragraph § 63.8186(b) or (d). Emissions of mercury are 

prohibited from each existing mercury cell chlor-alkali 

production facility and from each existing, new, or 

reconstructed mercury recovery facility. You must demonstrate 

compliance with this prohibition in accordance with the 

provisions in § 63.8236(e) and § 63.8246(d) and submit the 

certification of compliance required by § 63.8252(f).

5. Section 63.8192 is amended as follows:

a. Revising the introductory text;

b. Revising paragraph (g)(2)(i); and

c. Revising paragraph (g)(3).

The revisions read as follows:

§ 63.8192 What work practice standards must I meet?

Prior to achieving compliance with § 63.8190(b), 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.

* * * * *

(g) * * *

(2) * * *
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(i) Beginning on the compliance date specified for your 

affected source in § 63.8186(a), 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.

* * * * *

(3) Beginning on the compliance date specified for your 

affected source in § 63.8186(a), you must continuously monitor 

the mercury concentration in the cell room. Failure to monitor 

and record the data according to § 63.8256(c)(4)(ii) for 75 

percent of the time in any 6-month period constitutes a 

deviation.

* * * * *

6. Section 63.8226 is revised to read as follows:

§ 63.8226 What are my general requirements for complying with 

this subpart?

(a) You must be in compliance with the applicable emission 

limitations in § 63.8190 at all times. Prior to achieving 

compliance with § 63.8190(b), you must be in compliance with the 

applicable work practice standards in § 63.8192 at all times.

(b) At all times you must operate and maintain any 

affected source, including associated air pollution control 

equipment and monitoring equipment, in a manner consistent with 

safety and good air pollution control practices for minimizing 

emissions. The general duty to minimize emissions does not 
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require you to make any further efforts to reduce emissions if 

levels required by this standard have been achieved. 

Determination of whether such operation and maintenance 

procedures are being used will be based on information available 

to the Administrator which may include, but is not limited to, 

monitoring results, review of operation and maintenance 

procedures, review of operation and maintenance records, and 

inspection of the source.

7. Section 63.8230 is revised to read as follows:

§ 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 § 63.8186(a) for your 

affected source to demonstrate initial compliance with the 

applicable emission limit in § 63.8190(a)(2) for by-product 

hydrogen streams and end box ventilation system vents and the 

applicable emission limit in § 63.8190(a)(3) for mercury thermal 

recovery unit vents.

(b) For the applicable work practice standards in 

§ 63.8192 you must demonstrate initial compliance within 30 

calendar days after the compliance date that is specified for 

your affected source in § 63.8186(a).

8. Section 63.8232 is amended by removing and reserving

paragraph (a) to read as follows:
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§ 63.8232 [Amended]

(a) [Reserved.]

9. Section 63.8236 is amended by adding paragraph (e) to 

read as follows:

§ 63.8236 How do I demonstrate initial compliance with the 

emission limitations and work practice standards?

* * * * *

(e) For each affected source, you have demonstrated 

initial compliance with the emission limit in § 63.8190(b) if 

you have eliminated mercury emissions and you have submitted the 

compliance certification required by § 63.8252(f).

10. Section 63.8242 is amended by revising paragraph 

(a)(2) to read as follows:

§ 63.8242 What are the installation, operation, and maintenance 

requirements for my continuous monitoring systems?

(a) * * *

(2) Each mercury continuous emissions monitor analyzer 

must have a detector with the capability to detect a mercury 

concentration of either 0.5 times the mercury concentration 

level measured during the performance test conducted according 

to § 63.8232 or 0.1 μg/m3

.

* * * * *

11. Section 63.8243 is amended by revising paragraphs (a) 

introductory text and (a)(3) introductory text to read as 
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follows:

§ 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 § 63.8186(a) 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.

* * * * * 

(3) Beginning 52 weeks after the compliance date specified 

in § 63.8186(a) 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:

* * * * *

12. Section 63.8246 is amended by revising paragraph 

(b)(1) introductory text, and adding paragraph (d) to read as 

follows:

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

* * * * *

(b) * * * (1) For each mercury thermal recovery unit 

vent, you must demonstrate continuous compliance with the 

applicable emission limit specified in § 63.8190(a)(3) by 

maintaining the outlet mercury daily-average concentration no 

higher than the applicable limit. To determine the outlet 

mercury concentration, you must monitor according to paragraphs 

(b)(1)(i) or (ii) of this section.

* * * * *

(d) You must demonstrate continuous compliance with the 

emission limitations in § 63.8190(b) by operating with zero

mercury emissions.

13. Section 63.8248 is amended as follows:

a. Revising paragraph (a)(1); 

b. Revising paragraph (a)(2); and

c. Removing and reserving paragraph (b).

The revisions read as follows:

§ 63.8248 What other requirements must I meet?

(a) * * *

(1) You must report each instance in which you did not 

meet each emission limitation in § 63.8190 that applies to you. 

(2) You must report each instance in which you did not meet 

each work practice standard in § 63.8192 that applies to you
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* * * * *

(b) [Reserved.]

14. Section 63.8252 is amended by adding paragraph (f) to 

read as follows:

§ 63.8252 What notifications must I submit and when?

* * * * *

(f) You must submit a compliance certification no later 

than 60 days after the applicable compliance date specified in 

§ 63.8186(b) or (d). This certification must state that you 

have eliminated all mercury emissions and will not use any 

process in the future that will emit mercury. The certification 

should also include a statement as to whether you eliminated 

mercury emissions through conversion to a nonmercury process for 

chlorine production or whether chlorine is no longer produced at

the site.

15. Section 63.8254 is amended as follows:

a. Revising paragraph (a)(1); 

b. Revising paragraph (a)(2);

c. Removing and reserving paragraph (b)(4);

d. Revising paragraph (b)(7) introductory text;

e. Revising paragraph (b)(8) introductory text;

f. Revising paragraph (b)(8)(iv);

g. Revising paragraph (b)(8)(vi);

h. Revising paragraph (b)(9) introductory text;
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i. Revising paragraph (b)(9)(ii);

j. Revising paragraph (b)(9)(vi); and

k. Removing and reserving paragraph (c).

The revisions read as follows:

§ 63.8254 What reports must I submit and when?

(a) * * *

(1) The first compliance report must cover the period 

beginning on December 19, 2006, and ending on June 30, 2007.

(2) The first compliance report must be postmarked or 

delivered no later than July 31, 2007.

* * * * * 

(b) * * *

(4) [Reserved.]

* * * * *

(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 

§ 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.

* * * * *

(8) For each deviation from an emission limitation 
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occurring at an affected source where you are using a mercury 

continuous emission monitor, according to the site-specific 

monitoring plan required in § 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.

* * * * *

(iv) The date and time that each deviation started and 

stopped.

* * * * *

(vi) A breakdown of the total duration of the deviations 

during the reporting period including those that are due to 

control equipment problems, process problems, other known 

causes, and other unknown causes.

* * * * *

(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 § 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.

* * * * *
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(ii) Information on the number, duration, and cause of 

deviations (including unknown cause, if applicable), as 

applicable, and the corrective action taken.

* * * * *

(vi) A breakdown of the total duration of the deviations 

during the reporting period including those that are due to 

process problems, other known causes, and other unknown causes.

* * * * * 

(c) [Reserved.]

* * * * *

16. Section 63.8256 is amended by removing and reserving 

paragraph (a)(2) to read as follows:

§ 63.8256 What records must I keep?

(a) * * *

(2) [Reserved.]

* * * * *

17. Section 63.8266 is amended by revising the definitions 

of “Deviation;” and “Mercury cell chlor-alkali plant” to read as 

follows:

§ 63.8266 What definitions apply to this subpart?

* * * * *

Deviation means any instance in which an affected source 

subject to this subpart, or an owner or operator of such a 

source:
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(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; or

(3) Fails to take corrective actions within 48 hours that 

result in parameter monitoring values being within range.

* * * * *

Mercury cell chlor-alkali plant means all contiguous or 

adjoining property that is under common control, where a mercury 

cell chlor-alkali production facility and/or a mercury recovery 

facility is located. A property where only a mercury recovery 

facility is operating is considered a mercury cell chlor-alkali 

plant if a mercury cell chlor-alkali production facility had

operated on that property at any time in the past.

* * * * *

18. Table 10 to Subpart IIIII of Part 63 is revised to 

read as follows:

TABLE 10 TO SUBPART IIIII OF PART 63--APPLICABILITY OF GENERAL 

PROVISIONS TO SUBPART IIIII

As stated in § 63.8262, you must comply with the applicable 

General Provisions requirements according to the following 

table:
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Citation Subject Applies 

to 

Subpart 

IIIII

Explanation

§ 63.1 Applicability Yes

§ 63.2 Definitions Yes

§ 63.3 Units and Abbreviations Yes

§ 63.4 Prohibited Activities Yes

§ 63.5 Construction/

Reconstruction

Yes

§ 63.6(a) -

(g), (i), (j), 

except for 

(e)(1)(i) and 

(ii), (e)(3), 

and (f)(1)

Compliance with Standards 

and Maintenance 

Requirements

Yes

§ 63.6(e)(1)(i) 

and (ii), 

(e)(3), and 

(f)(1)

SSM Requirements No

§ 63.6(h) Compliance with Opacity 

and Visible Emission 

Standards

No Subpart IIIII 

does not have 

opacity and 

visible emission 

standards.

§ 63.7(a)(1), 

(b)-(h), except 

(e)(1)

Performance Testing 

Requirements

Yes Subpart IIIII 

specifies 

additional 

requirements 

related to sitespecific test 

plans and the 

conduct of 

performance 

tests.

§ 63.7(e)(1) Performance Testing 

Requirements Related to 

SSM

No
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§ 63.7(a)(2) Applicability and 

Performance Test Dates 

No Subpart IIIII 

requires the 

performance test 

to be performed 

on the 

compliance date.

§ 63.8(a)(1), 

(a)(3); (b); 

(c)(1)-(4), 

(6)-(8); (d); 

(e); and 

(f)(1)-(5)

Monitoring Requirements Yes

§ 63.8(a)(2) Continuous Monitoring 

System (CMS) Requirements

No Subpart IIIII 

requires a sitespecific 

monitoring plan 

in lieu of a 

promulgated 

performance 

specification 

for a mercury 

concentration 

CMS.

§ 63.8(a)(4) Additional Monitoring 

Requirements for Control 

Devices in ' 63.11

No Subpart IIIII 

does not require 

flares.

§ 63.8(c)(5) COMS Minimum Procedures No Subpart IIIII 

does not have 

opacity and 

visible emission 

standards.

§ 63.8(f)(6) Alternative to

Relative Accuracy Test

No Subpart IIIII 

does not require 

CEMS.

§ 63.8(g) Data Reduction No Subpart IIIII 

specifies 

mercury 

concentration 

CMS data 

reduction 

requirements.

§ 63.9(a)-(e), Notification Yes
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(g)-(j) Requirements

§ 63.9(f) Notification of VE/Opacity

Test

No Subpart IIIII 

does not have 

opacity and 

visible emission 

standards.

§ 63.10(a); 

(b)(1); 

(b)(2)(vi)-

(xii), (xiv); 

(b)(3); (c); 

(d)(1)-(2), 

(4); (e); (f)

Recordkeeping/Reporting Yes

§ 63.10(b)(2)

(i)- (v), 

(d)(5)

Recordkeeping/ Reporting 

Associated with Startup, 

Shutdown, and Malfunctions

No

§ 63.10(b)(2) 

(xiii)

CMS Records for RATA 

Alternative

No Subpart IIIII 

does not require 

CEMS.

§ 63.10(d)(3) Reporting Opacity or VE

Observations

No Subpart IIIII 

does not have 

opacity and 

visible emission 

standards.

§ 63.11 Flares No Subpart IIIII 

does not require 

flares.

§ 63.12 Delegation Yes

§ 63.13 Addresses Yes

§ 63.14 Incorporation by Reference Yes

§ 63.15 Availability of 

Information

Yes