Wednesday,

July 3, 2002

Part II

Environmental 

Protection Agency

40 CFR Part 63

National Emission Standards for 

Hazardous Air Pollutants: Mercury 

Emissions From Mercury Cell Chlor-Alkali 

Plants; Proposed Rules

44672 Federal Register / Vol. 67, No. 128 / Wednesday, July 3, 2002 / Proposed Rules 

ENVIRONMENTAL PROTECTION 

AGENCY 

40 CFR Part 63 

[FRL–7236–6] 

RIN 2060–AE85 

National Emission Standards for 

Hazardous Air Pollutants: Mercury 

Emissions From Mercury Cell ChlorAlkali Plants

AGENCY: Environmental Protection 

Agency (EPA).

ACTION: Proposed rule.

SUMMARY: This action proposes national 

emission standards for hazardous air 

pollutants (NESHAP) for mercury cell 

chlor-alkali plants. The proposed 

standards would limit mercury air 

emissions from these plants. The 

proposed standards would implement 

section 112(d) of the Clean Air Act 

(CAA) which requires all categories and 

subcategories of major sources and area 

sources listed in section 112(c) to meet 

hazardous air pollutant emission 

standards reflecting the application of 

the maximum achievable control 

technology (MACT). The proposed 

standards would reduce nationwide 

mercury emissions from these sources 

by about 4,100 kilograms per year (kg/

yr) (9,100 pounds per year (lb/yr)) from 

the levels allowed by the existing 

mercury NESHAP. 

Mercury is a neurotoxin that 

accumulates, primarily in the especially 

potent form of methylmercury, in 

aquatic food chains. The highest levels 

are reached in predator fish species. 

Mercury emitted to the air from various 

types of sources (usually in the 

elemental or inorganic forms) transports 

through the atmosphere and eventually 

deposits onto land or water bodies. 

When mercury is deposited to surface 

waters, natural processes (bacterial) can 

transform some of the mercury into 

methylmercury that accumulates in fish. 

The health effect of greatest concern due 

to methylmercury is neurotoxicity, 

particularly with respect to fetuses and 

young children.

DATES: Comments. Submit comments on 

or before September 3, 2002. 

Public Hearing. If anyone contacts the 

EPA requesting to speak at a public 

hearing by July 23, 2002, a public 

hearing will be held on August 2, 2002.

ADDRESSES: Docket. Docket No. A–

2000–32 contains supporting 

information used in developing the 

proposed standards for the mercury cell 

chlor-alkali plant source category. The 

docket is located at the U.S. EPA, 401 

M Street, SW., Washington, DC 20460 in 

Room M–1500, Waterside Mall (ground 

floor), and may be inspected from 8:30 

a.m. to 5:30 p.m., Monday through 

Friday, excluding legal holidays.

FOR FURTHER INFORMATION CONTACT: Mr. 

Iliam Rosario, Metals Group, Emission 

Standards Division (C439–02), U.S. 

EPA, Research Triangle Park, North 

Carolina 27711, telephone number: 

(919) 541–5308, facsimile: (919) 541–

5600, electronic mail address: 

rosario.iliam@epa.gov.

SUPPLEMENTARY INFORMATION: 

Comments. Comments and data may 

be submitted by electronic mail (e-mail) 

to: a-and-r-docket@epa.gov. Electronic 

comments must be submitted as an 

ASCII file to avoid the use of special 

characters and encryption problems and 

will also be accepted on disks in 

WordPerfect format. All comments 

and data submitted in electronic form 

must note the docket number: Docket 

No. A–2000–32. No confidential 

business information (CBI) should be 

submitted by e-mail. Electronic 

comments may be filed online at many 

Federal Depository Libraries. 

Commenters wishing to submit 

proprietary information for 

consideration must clearly distinguish 

such information from other comments 

and clearly label it as CBI. Send 

submissions containing such 

proprietary information directly to the 

following address, and not to the public 

docket, to ensure that proprietary 

information is not inadvertently placed 

in the docket: OAQPS Document 

Control Office (C404–02) Attention: 

Iliam Rosario, Metals Group, Emission 

Standards Division, U.S. EPA, Research 

Triangle Park, NC 27711. The EPA will 

disclose information identified as CBI 

only to the extent allowed by the 

procedures set forth in 40 CFR part 2. 

If no claim of confidentiality 

accompanies a submission when it is 

received by the EPA, the information 

may be made available to the public 

without further notice to the 

commenter. 

Public Hearing. Persons interested in 

presenting oral testimony or inquiring 

as to whether a hearing is to be held 

should contact Cassie Posey, telephone 

number: (919) 541–0069. Persons 

interested in attending the public 

hearing must also call Cassie Posey to 

verify the time, date, and location of the 

hearing. The public hearing will provide 

interested parties the opportunity to 

present data, views, or arguments 

concerning the proposed emission 

standards. 

Docket. The docket is an organized 

and complete file of all the information 

considered by the EPA in rule 

development. The docket is a dynamic 

file because material is added 

throughout the rulemaking process. The 

docketing system is intended to allow 

members of the public and industries 

involved to readily identify and locate 

documents so that they can effectively 

participate in the rulemaking process. 

Along with the proposed and 

promulgated standards and their 

preambles, the contents of the docket 

will serve as the record in the case of 

judicial review. (See section 

307(d)(7)(A) of the CAA.) The regulatory 

text and other materials related to this 

rulemaking are available for review in 

the docket or copies may be mailed on 

request from the Air Docket by calling 

(202) 260–7548. A reasonable fee may 

be charged for copying docket materials. 

World Wide Web Information. In 

addition to being available in the 

docket, an electronic copy of today’s 

proposed rule will also be available 

through EPA’s World Wide Web site. 

Following signature, a copy of the rule 

will be posted on our policy and 

guidance page for newly proposed or 

promulgated rules: http://www.epa.gov/

ttn/oarpg. The web site provides 

information and technology exchange in 

various areas of air pollution control. If 

more information regarding the web site 

is needed, call our web site help line at 

(919) 541–5384. 

Regulated entities. Entities potentially 

affected by this action include plants 

engaged in the production of chlorine 

and caustic in mercury cells. Regulated 

categories and entities include those 

sources listed in the primary Standard 

Industrial Classification code 2812 or 

North American Information 

Classification System code 325181. 

This description is not intended to be 

exhaustive, but rather provides a guide 

for readers regarding entities likely to be 

regulated by this action. To determine 

whether your facility, company, 

business, organization, etc., is regulated 

by this action, you should carefully 

examine § 63.8182 of the proposed rule. 

If you have questions regarding the 

applicability of this action to a 

particular entity, consult the person 

listed in the preceding FOR FURTHER

INFORMATION CONTACT section. 

Outline. The information presented in 

this preamble is organized as follows:

I. Background 

A. What is the source of authority for 

development of NESHAP? 

B. What criteria are used in the 

development of NESHAP? 

C. What is a mercury cell chlor-alkali 

plant? 

D. What are the health effects associated 

with mercury? 

Federal Register / Vol. 67, No. 128 / Wednesday, July 3, 2002 / Proposed Rules 44673

E. How does this action relate to the part 

61 Mercury NESHAP? 

II. Summary of Proposed Standards 

A. What is the source category? 

B. What are the affected sources and 

emission points to be regulated? 

C. What are the emission limitations? 

D. What are the work practice standards? 

E. What are the operation and maintenance 

requirements? 

F. How are initial and continuous 

compliance with the emission 

limitations to be demonstrated? 

G. How are initial and continuous 

compliance with the work practice 

standards to be demonstrated? 

H. What are the notification and reporting 

requirements? 

I. What are the recordkeeping 

requirements? 

III. Rationale for Selecting the Proposed 

Standards 

A. How did we select the source category? 

B. How did we select the affected sources 

and emission points to be regulated? 

C. How did we select the form of the 

standards? 

D. How did we determine the basis and 

level of the proposed standards for 

existing sources? 

E. How did we determine the basis and 

level of the proposed standards for new 

sources? 

F. How did we select the testing and initial 

compliance requirements? 

G. How did we select the continuous 

compliance requirements? 

H. How did we select the notification, 

recordkeeping, and reporting 

requirements?

IV. Summary of Environmental, Energy, Cost, 

and Economic Impacts 

A. What are the air emission impacts? 

B. What are the non-air health, 

environmental, and energy impacts? 

C. What are the cost and economic 

impacts? 

V. Solicitation of Comments and Public 

Participation 

VI. Administrative Requirements 

A. Executive Order 12866, Regulatory 

Planning and Review 

B. Executive Order 13132, Federalism 

C. Executive Order 13175, Consultation 

and Coordination with Indian Tribal 

Governments 

D. Executive Order 13045, Protection of 

Children from Environmental Health 

Risks and Safety Risks 

E. Unfunded Mandates Reform Act of 1995 

F. Regulatory Flexibility Act (RFA), as 

amended by the Small Business 

Regulatory Enforcement Fairness Act of 

1996 (SBREFA) 

G. Paperwork Reduction Act 

H. National Technology Transfer and 

Advancement Act 

I. Executive Order 13211, Actions 

Concerning Regulations that 

Significantly Affect Energy Supply, 

Distribution, or Use

I. Background 

A. What Is the Source of Authority for 

Development of NESHAP? 

Section 112 of the CAA contains our 

authorities for reducing emissions of 

hazardous air pollutants (HAP). Section 

112(d) requires us to promulgate 

regulations establishing emission 

standards for each category or 

subcategory of major sources and area 

sources of HAP listed pursuant to 

section 112(c). Section 112(d)(2) 

specifies that emission standards 

promulgated under the section shall 

require the maximum degree of 

reductions in emissions of the HAP 

subject to section 112 that are deemed 

achievable considering cost and any 

non-air quality health and 

environmental impacts and energy 

requirements. 

Each national emission standard for 

hazardous air pollutants (NESHAP) 

established reflects the maximum 

degree of reduction in emissions of HAP 

that is achievable. This level of control 

is commonly referred to as maximum 

achievable control technology (MACT). 

Section 112(c)(6) requires us to list 

source categories and subcategories 

assuring that sources accounting for not 

less than 90 percent of the aggregate 

emissions of each of seven specific 

pollutants (including mercury) are 

subject to standards under section 

112(d) of the CAA. 

Mercury cell chlor-alkali plants are 

among the sources listed to achieve the 

90 percent goal for mercury. 

B. What Criteria Are Used in the 

Development of NESHAP? 

Section 112(d)(2) specifies that 

NESHAP for new and existing sources 

must reflect the maximum degree of 

reduction in HAP emissions that is 

achievable, taking into consideration the 

cost of achieving the emissions 

reductions, any non-air quality health 

and environmental benefits, and energy 

requirements. This level of control is 

commonly referred to as MACT. 

Section 112(d)(3) defines the 

minimum level of control or floor 

allowed for NESHAP. In essence, the 

MACT floor ensures that the standard is 

set at a level that assures that all 

affected sources achieve the level of 

control at least as stringent as that 

already achieved by the bettercontrolled and lower-emitting sources 

in each source category or subcategory. 

For new sources, the MACT floor cannot 

be less stringent than the emission 

control that is achieved in practice by 

the best-controlled similar source. The 

MACT standards for existing sources 

cannot be less stringent than the average 

emission limitation achieved by the 

best-performing 12 percent of existing 

sources in the category or subcategory 

(or the best-performing five sources for 

categories or subcategories with fewer 

than 30 sources). 

In developing MACT, we also 

consider control options that are more 

stringent than the floor. We may 

establish standards more stringent than 

the floor based on the consideration of 

cost of achieving the emissions 

reductions, any non-air quality health 

and environmental impacts, and energy 

impacts. 

C. What Is a Mercury Cell Chlor-alkali 

Plant? 

1. Mercury Cell Chlor-Alkali Production 

Facilities 

At a mercury cell chlor-alkali plant, 

mercury cell chlor-alkali production 

facilities are used to manufacture 

chlorine and caustic as co-products and 

hydrogen as a by-product through the 

electrolytic decomposition of brine in 

mercury cells. The central unit is the 

mercury cell which is a device 

comprised of an electrolyzer 

(electrolytic cell) and decomposer with 

one or more end boxes and other 

components linking them. While each 

mercury cell is an independent 

production unit, numerous cells are 

connected electrically in series to form 

a cell circuit. Cells are situated in a cell 

room and typically arranged in two 

rows separated by a center aisle. The 

cell room is generally a two-story 

structure in which mercury cells are 

housed on the upper floor. The lower 

floor houses various process and 

housekeeping functions. The number of 

mercury cells at a given plant ranges 

from 24 to 116 and averages 56. A 

mercury cell involves two distinct 

reactions which occur in separate 

vessels. The electrolyzer produces 

chlorine gas, and the decomposer 

produces hydrogen gas and caustic 

solution (sodium hydroxide or 

potassium hydroxide). The electrolyzer 

can be described as an elongated, 

shallow steel trough enclosed by side 

panels and a top cover. A typical 

electrolyzer measures about 15 meters 

(about 50 feet) in length and 1.5 meters 

(about 5 feet) in width and holds about 

3,600 kilograms (around 8,000 pounds) 

of mercury. The decomposer is a 4-to5 feet high cylindrical vessel located at 

the outlet end of the electrolyzer and is 

usually oriented vertically. The 

electrolyzer and the decomposer are 

typically linked by an inlet end box and 

an outlet end box.

A shallow stream of liquid mercury 

flows continuously between the 

44674 Federal Register / Vol. 67, No. 128 / Wednesday, July 3, 2002 / Proposed Rules 

electrolyzer and the decomposer. The 

mercury enters the cell at the inlet end 

box and flows down a slight grade to the 

outlet end box, where it flows out of the 

cell into the decomposer. After being 

processed in the decomposer, the 

mercury is pumped back to the inlet end 

box of the cell. 

Saturated brine (sodium chloride 

solution or potassium chloride solution) 

is fed to the electrolytic cell via the inlet 

end box and flows toward the outlet end 

box above the shallow layer of mercury. 

Both brine and mercury flow beneath 

dimensionally stable metal anodes, 

typically made of a titanium substrate 

with a metal catalyst that are suspended 

in the electrolyzer top. The flowing 

mercury serves as the cathode. 

Electric current applied between the 

anodes and the mercury cathode causes 

a reaction that produces chlorine at the 

anode, while an alkali metal (sodium or 

potassium) binds with the mercury as 

an amalgam at the cathode. The chlorine 

gas is collected at the top of the cell and 

transported to an ancillary gas 

purification system followed in most 

cases by a liquefaction facility. The 

alkali metal/mercury amalgam exits via 

the outlet end box and enters the 

decomposer. The brine, whose salt 

content has been partially depleted in 

the reaction, also exits the cell via the 

outlet end box and is transferred to an 

ancillary brine preparation system. 

The decomposer functions as a 

packed bed reactor in which the alkali 

metal/mercury amalgam contacts 

deionized water in the presence of a 

catalyst. The amalgam reacts with the 

water, liberating the mercury and 

yielding caustic soda (sodium 

hydroxide) or caustic potash (potassium 

hydroxide) and hydrogen. The caustic 

and mercury are separated in a trap at 

the end of the decomposer. The caustic 

and hydrogen are each transferred to 

ancillary treatment, and the mercury is 

pumped back to the inlet end of the cell. 

As previously noted, end boxes serve 

as connections between the electrolyzer 

and decomposer in a mercury cell. The 

inlet end box collects and combines raw 

materials at the inlet end of the cell, and 

the outlet end box separates and directs 

various materials out of the cell. An 

end-box ventilation system, which is 

present at most but not all plants, 

evacuates the vapor spaces of the end 

boxes. The end-box ventilation system 

also commonly evacuates the vapor 

space of other vessels and process 

equipment, such as pump seals, wash 

water tanks, and caustic tanks and 

headers. In most cases, mercury 

contained in this equipment is covered 

with a layer of water or other aqueous 

liquid so the air being pulled into the 

end-box ventilation system is not in 

direct contact with mercury. However, 

due to the elevated temperatures in this 

equipment, particularly end boxes, 

mercury diffuses through the liquid and 

is present in the vapor spaces. The 

concentration of mercury in end-box 

ventilation systems before any steps are 

taken to remove mercury varies greatly 

depending on the vacated equipment. 

The collected gases are usually cooled 

and then treated in a mist eliminator 

and other control equipment prior to 

being discharged to the atmosphere. It is 

the mercury remaining in the treated 

stream that causes the end-box 

ventilation system vent to be a point 

source of mercury air emissions for 

plants that have these systems. 

Important ancillary operations at a 

mercury cell chlor-alkali plant include 

chlorine purification and liquefaction, 

brine preparation, caustic purification, 

by-product hydrogen cleaning, and 

wastewater treatment. 

Chlorine gas is collected under 

vacuum from each mercury cell and fed 

into a header system leading out of the 

cell room. The chlorine then undergoes 

cooling, mist elimination, and drying. 

Only trace amounts of mercury remain 

in the product chlorine gas, typically 

less than 0.03 parts per million (ppm). 

Thus, limited mercury emissions are 

associated with the chlorine purification 

operation, as this level is achieved 

without any steps for mercury removal 

and is consistent with final mercury 

concentrations for well-controlled 

gaseous by-product hydrogen streams. 

In most instances, further cooling, 

compression, and liquefaction are 

conducted to obtain liquid chlorine. 

Brine flows in a continuous loop 

through the mercury cells and the brine 

preparation system which provides 

clean saturated brine for electrolysis. An 

important function of the brine system 

is the removal of impurities naturally 

associated with salt such as calcium, 

iron, and aluminum. The presence of 

these elements can adversely affect cell 

efficiency. These impurities are 

removed by the addition of caustic and 

sodium carbonate which react to form 

metal precipitates that are removed by 

filtration. Subsequently, the brine is 

acidified to remove excess caustic, 

subjected to heat exchange for 

temperature adjustment, and returned to 

the mercury cells as clean saturated 

brine. Mercury exists in the brine 

system in the form of dissolved 

mercuric chloride and on the order of 3 

to 25 ppm. The low vapor pressure of 

mercuric chloride, which is 

approximately 30 times lower than that 

of elemental mercury at 35°C, limits the 

potential for emissions of mercury from 

the brine system.

Because the caustic solution produced 

directly from the decomposer is 

commercial grade, the only additional 

treatment needed is mercury removal. 

The concentration of mercury in the 

caustic stream leaving the decomposer 

ranges from about 3 to 15 ppm. Mercury 

is removed by cooling and filtration. 

Residual mercury contained in the 

caustic product is typically around 0.06 

ppm. 

Hydrogen gas exiting a decomposer 

contains mercury vapor. A mercurysaturated hydrogen gas stream typically 

leaves a decomposer at a temperature 

over 200°F. The mercury concentration 

of this stream can be as high as 3,500 

milligrams per cubic meter (mg/m3). 

Accordingly, in most situations, each 

decomposer is equipped with an 

adjacent cooler through which the 

hydrogen gas stream is routed to 

condense mercury and return it to the 

mercury cell. After initial cooling, the 

hydrogen gas from each decomposer is 

collected into a common header. The 

combined gas is then treated for 

mercury with additional cooling and 

adsorption (or absorption) control 

equipment. The cleaned hydrogen gas is 

then either burned as fuel in a boiler, 

transferred to another process as a raw 

material, or vented directly to the 

atmosphere. Due to the mercury 

remaining in the treated stream, the byproduct hydrogen stream is a point 

source of mercury air emissions. 

Mercury cell chlor-alkali plants 

generate a variety of aqueous waste 

streams that contain mercury and are 

treated in a wastewater treatment 

system. These wastewaters originate 

from a variety of sources, ranging from 

wastewaters produced from cell room 

washdowns and cleanup activities to 

liquids or slurries produced from 

purged brine from the brine system and 

backwash water from the filtration 

equipment used for caustic purification. 

Wastewater treatment applied at most 

mercury cell chlor-alkali plants entails 

three basic steps. First, sodium 

hydrosulfide is added to the wastewater 

(which contains both elemental mercury 

and mercury compounded as mercuric 

chloride) to form mercuric sulfide. This 

compound has a very low vapor 

pressure which practically eliminates 

the potential for mercury air emissions 

from wastewater treatment. Next, the 

mercuric sulfide is removed through 

precipitation and filtration which 

results in a liquid fraction and a 

mercuric sulfide filter cake. Any 

dissolved mercury contained in the 

liquid is removed by treatment in a 

carbon adsorber prior to being 

Federal Register / Vol. 67, No. 128 / Wednesday, July 3, 2002 / Proposed Rules 44675

discharged in accordance with a plant’s 

discharge permit. The wastewater 

treatment sludges produced, which 

consist mainly of the mercuric sulfide 

filter cake, are classified as hazardous 

under Resource Conservation and 

Recovery Act (RCRA) regulations (40 

CFR part 261, subpart D). This waste, 

designated as K106, must be treated for 

mercury removal prior to disposal or 

landfilling which generally means high 

temperature treatment. 

2. Mercury Recovery Facilities

Nine mercury cell chlor-alkali plants 

have mercury recovery facilities on-site 

to recover elemental mercury from 

mercury-containing wastes. The wastes 

treated include those considered K106 

wastes, as cited above, and debris and 

nondebris D009 wastes. The D009 

wastes, as classified under RCRA 

regulations (40 CFR part 261, subpart 

D), are nonspecific mercury-containing 

wastes. Debris wastes include any 

contaminated material or item greater 

than 21⁄2 inches in any one dimension, 

such as hardware, protective gear, 

piping, and equipment. Nondebris 

wastes include graphite from 

decomposers, cell room sump sludges, 

spent carbon media from carbon 

adsorption control devices, and other 

small solids. 

The most commonly used process is 

thermal recovery (retorting), where 

mercury-containing wastes are heated to 

volatilize the mercury which is then 

condensed and recovered. Six plants 

each operate a mercury thermal 

recovery unit. In such a unit, mercury 

in wastes is driven to the vapor phase 

at temperatures over 1,000°F inside one 

or more retorts. The retort off-gas, which 

is rich in mercury vapor, is routed 

through cooling equipment to condense 

the mercury for recovery. However, 

because it is not possible to condense all 

of the mercury, the off-gas is typically 

routed through polishing control 

equipment to further reduce mercury 

before the stream is discharged to the 

atmosphere. This causes the mercury 

thermal recovery unit vent to be a point 

source of mercury air emissions. 

Mercury that never vaporizes and 

subsequently is neither condensed nor 

emitted remains in the retort ash, whose 

mercury content is limited by RCRA 

land disposal restrictions (40 CFR part 

268, subpart E). 

Mercury thermal recovery units can 

be classified, based on the type of retort 

used, as oven type units and non-oven 

type units. Three plants have batch oven 

retorts, and three plants have non-oven 

retorts (rotary kiln or single hearth). 

There are differences between the two 

types related to operating temperature 

and residence time. Oven retorts have 

lower operating temperatures (around 

1,000°F) and substantially longer 

residence times (24 to 54 hours) than do 

kilns which operate at around 1,375°F 

with residence times approaching 3 

hours. 

Noteworthy among all six thermal 

recovery units is the relatively small 

volume of exhaust gas generated. 

Volumetric flow rates range from 

around 50 standard cubic feet per 

minute (scfm) on one oven type unit to 

1,200 scfm on one non-oven type unit. 

Non-oven type units have higher 

volumetric flow rates with an average 

flow rate of 1,000 scfm and a median of 

1,075 scfm than oven type units with an 

average of 130 scfm and a median of 100 

scfm.

Two of the nine plants use a chemical 

process in which mercuric sulfide and 

elemental mercury in wastes are 

chemically transformed to mercuric 

chloride from which elemental mercury 

is then precipitated. This process differs 

from mercury thermal recovery in that 

it is an entirely liquid-phase operation. 

Moreover, owing to the low vapor 

pressure of mercuric chloride, the 

potential for mercury air emissions from 

this process is limited. Mercury that is 

not converted and recovered remains in 

the processed waste materials whose 

mercury content is limited by RCRA 

land disposal restrictions for 

nonthermal mercury recovery processes 

(40 CFR part 268, subpart E). 

The ninth plant uses a batch 

purification still for recovering 

elemental mercury only from end-box 

residues which are high in mercury 

content. The system involves heating 

small batches of end-box residues to 

volatilize the mercury contained 

followed by a condenser for mercury 

recovery. This contrasts with thermal 

recovery units that treat large volumes 

of low mercury content wastes. The still 

is operated under vacuum such that the 

gas stream after the condenser is routed 

through two carbon adsorption beds in 

series to limit mercury air emissions. 

The system is used only a few times per 

year for 1 to 2 days at a time. Due to the 

small volumetric flow rate and mercury 

concentration of the vented stream and 

limited operation of the still, mercury 

air emissions are very low from recovery 

in the batch purification still. 

Fugitive mercury emissions can occur 

due to leaking equipment, liquid 

mercury spills, or accumulations in 

many locations throughout mercury cell 

chlor-alkali production facilities and 

mercury recovery facilities, including 

areas of maintenance activities, liquid 

mercury collection and handling, and 

storage for mercury-containing wastes. 

Most of these sources are associated 

with cell rooms. Liquid mercury 

exposed to the atmosphere evaporates at 

a rate depending on temperature, air 

flow, and other variables. Methods of 

controlling fugitive mercury emissions 

include the containment of liquid 

mercury leaks, clean up of liquid 

mercury spills and accumulations, 

repair of equipment leaking liquid 

mercury, and containment of mercurycontaining wastes under an aqueous 

liquid or in closed containers. Since 

liquid mercury can be visually 

identified, routine visual inspections are 

an effective method to detect these 

problems. Mercury vapor leaks, by 

comparison, are much more difficult to 

detect and typically result in higher 

emissions. Vapor leaks occur mostly at 

the decomposer and in the hydrogen 

system. 

D. What are the Health Effects 

Associated With Mercury? 

Mercury is highly toxic, persistent, 

and bioaccumulates in the food chain. 

Most people have some exposure to 

mercury as a result of normal daily 

activities. People may be exposed to 

mercury through inhalation of ambient 

air; consumption of contaminated food, 

water, or soil; and/or dermal exposure 

to substances containing mercury. Also, 

exposures occur as the result of dental 

amalgams and from various other 

sources. 

Mercury is a naturally occurring 

element that is found in air, water, and 

soil in various inorganic and organic 

forms. The three primary forms of 

interest are elemental mercury, 

inorganic mercury, and methylmercury. 

As mercury moves through 

environmental media, it undergoes 

complex transformations. 

Mercury emitted to the air from 

various types of sources (usually in 

elemental or inorganic forms) transports 

through the atmosphere and eventually 

deposits onto land or water bodies. 

Once deposited, natural processes can 

transform some of the mercury into 

methylmercury which is a highly toxic, 

more bioavailable form that 

biomagnifies in the aquatic food chain 

(such as in fish). Generally, fish 

consumption dominates the pathway for 

human and wildlife exposure to 

mercury.

Inhalation is the primary direct 

exposure route of concern for elemental 

mercury because this form strongly 

partitions to air. Absorption of 

elemental mercury vapor occurs rapidly 

through the lungs. Once absorbed, 

elemental mercury is readily distributed 

throughout the body; it crosses both 

placental and blood-brain barriers. The 

44676 Federal Register / Vol. 67, No. 128 / Wednesday, July 3, 2002 / Proposed Rules 

1This regulatory program was originally set forth 

at 38 FR 8826, April 6, 1973; and amended at 40 

FR 48302, October 14, 1975; 47 FR 24704, June 8, 

1982; 49 FR 35770, September 12, 1984; 50 FR 

46294, November 7, 1985; 52 FR 8726, March 19, 

1987; and 53 FR 36972, September 23, 1988.

elemental mercury is oxidized to 

divalent mercury in most body tissues. 

Once elemental mercury crosses these 

barriers and is oxidized to divalent 

mercury, return to the general 

circulation is impeded, and mercury can 

be retained in brain tissue. Effects on 

the nervous system appear to be the 

most sensitive toxicological endpoint 

following exposure to elemental 

mercury. Exposures above the threshold 

level can result in tremors, nervousness, 

insomnia, neuromuscular changes (such 

as weakness, muscle atrophy, and 

muscle twitching), headaches, 

polyneuropathy, and memory loss. 

Inhalation and ingestion exposure 

routes are of interest for inorganic 

mercury because this form is found in 

air and other media such as soils and 

water. There is some limited 

information suggesting that about 40 

percent of the inhaled inorganic 

mercury is absorbed. Absorption of 

inorganic mercury through the 

gastrointestinal tract varies with the 

particular mercuric salt involved. The 

portion that is absorbed remains in the 

body for a considerable length of time. 

The reported half-life of inorganic 

mercury in blood is about 20 to 66 days. 

There is no evidence that inorganic 

mercury is methylated to form 

methylmercury in the human body. The 

inorganic mercury has a limited 

capacity for penetrating the blood-brain 

or placental barriers. Limited data 

suggest that inorganic mercury is a 

possible human carcinogen. The most 

sensitive general systemic adverse effect 

due to exposure to inorganic mercury is 

the formation of autoimmune 

glomerulonephritis (that is, 

inflammation of the kidney). 

Ingestion is the primary exposure 

route of interest for methylmercury. 

Dietary methylmercury is almost 

completely absorbed into the blood and 

distributed to all tissues, including the 

brain. It also readily passes through the 

placenta to the fetus and fetal brain. 

Methylmercury has a relatively long 

half-life in the human body (about 70 to 

80 days). Neurotoxicity is the health 

effect of greatest concern with 

methylmercury exposure. The 

developing fetus is considered most 

sensitive to the effects from 

methylmercury. Therefore, women of 

child-bearing age are the population of 

greatest concern. During several 

poisoning incidents in Minamata, Japan, 

in the 1950’s and Iraq in the 1970’s, 

children born of women who were 

exposed to high doses of methylmercury 

during pregnancy through ingestion of 

contaminated fish or grain suffered 

neurological harms. These harms 

included death, cerebral palsy, or 

delayed onset of walking and talking. 

Also, lower in utero exposures have 

resulted in delays and deficits in 

learning abilities.

E. How Does This Action Relate to the 

Part 61 Mercury NESHAP? 

We promulgated the National 

Emission Standard for Mercury on April 

6, 1973 (40 CFR part 61, subpart E).1

Those standards (hereafter referred to as 

the Mercury NESHAP) limit mercury 

emissions from mercury cell chlor-alkali 

plants as well as mercury ore processing 

facilities and sludge incineration and 

drying plants. Specifically, the Mercury 

NESHAP limits mercury emissions from 

mercury cell chlor-alkali plants to 2,300 

grams per day and requires that mercury 

emissions be measured (in a one-time 

test) from hydrogen streams, end-box 

ventilation systems, and the cell room 

ventilation system. As an alternative to 

measuring ventilation emissions from 

the cell room to demonstrate 

compliance, the Mercury NESHAP 

allows an owner or operator to assume 

a ventilation emission value of 1,300 

grams per day of mercury providing the 

owner/operator adheres to a suite of 

approved design, maintenance and 

housekeeping practices. Every mercury 

cell chlor-alkali plant currently in 

operation in the United States complies 

with the cell room ventilation 

provisions by carrying out these 

practices rather than by measuring 

mercury emissions discharged from the 

cell room. Since every plant uses the 

1,300 grams per day assumed value for 

its cell room ventilation emissions, 

subtracting the 1,300 grams per day cell 

room value from the 2,300 grams per 

day plantwide standard effectively 

creates an emission limit for the 

combined emissions from hydrogen 

streams and end-box ventilation systems 

of 1,000 grams per day.

The requirements in today’s proposed 

standards are more stringent than the 

requirements in the Mercury NESHAP. 

Using the 1,000 grams per day value as 

the baseline, we estimate that the 

mercury emissions would be reduced to 

less than 60 grams per day (on average) 

by the proposed rule. This represents 

about 94 percent reduction from the 

Mercury NESHAP baseline for vents. In 

addition, the work practice standards in 

today’s proposal represent the most 

explicit compilation of practices 

currently employed by the industry, 

along with detailed recordkeeping and 

reporting requirements and 

requirements that supplement existing 

RCRA provisions for the storage of 

mercury-containing wastes. While we 

cannot quantify the mercury emissions 

reductions that would be achieved by 

the proposed work practice standards, 

we are confident that their 

implementation would result in 

additional reductions in mercury 

emissions beyond that currently 

achieved by the existing Mercury 

NESHAP.

We believe that every aspect of the 

Mercury NESHAP that applies to 

mercury cell chlor-alkali plants is 

addressed in today’s proposed 40 CFR 

part 63, subpart IIIII. In fact, as 

discussed above, the proposed 

requirements are more stringent than 

the respective requirements in the 

Mercury NESHAP. Consequently, we 

believe that when mercury cell chloralkali plants are required to comply 

with the proposed rule as the 

promulgated, the requirements of the 

Mercury NESHAP that apply to them 

will no longer be relevant or applicable. 

Therefore, upon the proposed 

compliance date as indicated in 

§ 63.8186 of the proposed rule, mercury 

cell chlor-alkali plants will no longer 

have any obligation to comply with the 

Mercury NESHAP, nor will they be 

allowed to comply with the Mercury 

NESHAP instead of the applicable 

provisions in the proposed 40 CFR part 

63, subpart IIIII. Specifically, we are 

proposing that affected sources subject 

to the proposed rule would no longer be 

subject to §§ 61.52(a), 61.53(b) and (c), 

and 61.55(b), (c) and (d) of 40 CFR part 

61, subpart E, after the compliance date 

which is proposed to be 2 years 

following the promulgation of the final 

rule. 

II. Summary of the Proposed Standards 

A. What Is the Source Category? 

The source category is Chlorine 

Production. However, this proposal only 

applies to one type of chlorine 

production process—the mercury cell 

chlor-alkali process. Today’s proposal 

applies to all plants engaged in the 

manufacture of chlorine and caustic in 

mercury cells. Other chlor-alkali cell 

types used to produce chlorine and 

caustic, such as diaphragm cell and 

membrane cell technologies, would not 

be covered by this proposed rule 

because they do not emit mercury. 

Emissions of chlorine and HCL from all 

chlorine production facilities are 

addressed in a separate action elsewhere 

in today’s Federal Register. 

Federal Register / Vol. 67, No. 128 / Wednesday, July 3, 2002 / Proposed Rules 44677

B. What Are the Affected Sources and 

Emission Points To Be Regulated? 

The proposed rule defines two 

affected sources: mercury cell chloralkali production facilities and mercury 

recovery facilities. The former includes 

all cell rooms and ancillary operations 

used in the manufacture of chlorine, 

caustic, and by-product hydrogen at a 

plant site. The latter includes all 

processes and associated operations 

needed for mercury recovery from 

wastes. 

Emission points addressed within 

mercury cell chlor-alkali production 

facilities include each mercury cell byproduct hydrogen stream, each mercury 

cell end-box ventilation system vent, 

and fugitive emission sources 

throughout each cell room and various 

areas. Emission points addressed within 

mercury recovery facilities include each 

mercury thermal recovery unit vent and 

fugitive emission sources associated 

with storage areas for mercurycontaining wastes. 

C. What Are the Emission Limitations? 

For new or reconstructed mercury cell 

chlor-alkali production facilities, the 

proposed rule would prohibit mercury 

emissions. 

For existing mercury cell chlor-alkali 

production facilities with end-box 

ventilation systems, we are proposing 

that aggregate mercury emissions from 

all by-product hydrogen streams and 

end-box ventilation system vents not 

exceed 0.067 grams of total mercury 

emitted per megagram of chlorine 

produced (grams Hg/Mg Cl2), or 1.3 x 

10¥4 pounds of total mercury per ton of 

chlorine produced (lb Hg/ton Cl2). For 

existing mercury cell chlor-alkali 

production facilities without end-box 

ventilation systems, we are proposing 

that mercury emissions from all byproduct hydrogen streams not exceed 

0.033 grams Hg/Mg Cl2, or 0.66 × 10¥4

lb Hg/ton Cl2. In addition, we are 

proposing that separate mercury 

concentration operating limits be 

established for each affected by-product 

hydrogen stream and each affected endbox ventilation system vent. The 

mercury concentration operating limits 

would be based only on elemental 

mercury, and each vent stream outlet 

would be continuously monitored for 

elemental mercury to show relative 

changes in mercury levels.

For new, reconstructed, or existing 

mercury recovery facilities with oven 

type mercury thermal recovery units, we 

are proposing that total mercury 

emissions not exceed 23 milligrams per 

dry standard cubic meter (mg/dscm) 

from each oven type unit vent. For new, 

reconstructed, or existing mercury 

recovery facilities with non-oven type 

mercury thermal recovery units, the 

proposed limit is 4 mg/dscm. 

Additionally, we are proposing that a 

mercury concentration operating limit 

(based on elemental mercury) be 

established concurrent with the initial 

performance test for each mercury 

thermal recovery unit vent. 

D. What Are the Work Practice 

Standards? 

We are proposing a set of work 

practice standards to address and 

mitigate fugitive mercury releases at 

mercury cell chlor-alkali plants. These 

provisions include specific equipment 

standards such as the requirement that 

end boxes either be closed (that is, 

equipped with fixed covers), or that 

end-box headspaces be routed to a 

ventilation system. Other examples 

include requirements that piping in 

liquid mercury service have smooth 

interiors, that cell room floors be free of 

cracks and spalling and coated with a 

material that resists mercury absorption, 

and that containers used to store liquid 

mercury have tight-fitting lids. The 

proposed work practice standards also 

include operational requirements. 

Examples of these include requirements 

to allow electrolyzers and decomposers 

to cool before opening, to keep liquid 

mercury in end boxes and mercury 

pumps covered by an aqueous liquid at 

a temperature below its boiling point at 

all times, to maintain end-box access 

port stoppers in good sealing condition, 

and to rinse all parts removed from the 

decomposer for maintenance prior to 

transport to another work area. 

A cornerstone of the proposed work 

practice standards is the inspection 

program for equipment problems, 

leaking equipment, liquid mercury 

accumulations and spills, and cracks or 

spalling in floors and pillars and beams. 

Specifically, the proposed rule would 

require that visual inspections for 

equipment problems, such as end-box 

access port stoppers not securely in 

place, liquid mercury in open 

containers not covered by an aqueous 

liquid, or leaking vent hoses, be 

conducted twice each day (once every 

12 hours). If a problem is found during 

an inspection, the owner or operator 

would need to take immediate action to 

correct the problem. Monthly 

inspections for cracking or spalling in 

cell room floors would also be required 

as well as semiannual inspections for 

cracks and spalling on pillars and 

beams. Any cracks or spalling found 

would need to be corrected within 1 

month. 

Visual inspections for liquid mercury 

spills or accumulations would be 

required twice per day. If a liquid 

mercury spill or accumulation is 

identified during an inspection, the 

owner or operator would need to initiate 

cleanup of the liquid mercury within 1 

hour of its detection. Acceptable 

cleanup methods would include wet 

vacuum cleaning, washing to a trench or 

canal with an aqueous liquid cover, or 

a suitable alternative method approved 

upon petition. 

In addition to cleanup, the proposed 

rule would require that an inspection of 

equipment in the area of the spill or 

accumulation be conducted to identify 

the source of the liquid mercury. If the 

source is found, the owner or operator 

would be required to repair the leaking 

equipment as discussed below. If the 

source is not found, the owner or 

operator would be required to reinspect 

the area every 6 hours until the source 

is identified or until no additional 

liquid mercury is found at that location. 

Inspections of specific equipment for 

liquid mercury leaks would be required 

once per day. If leaking equipment is 

identified, the proposed rule would 

require that any dripping mercury be 

contained and covered by an aqueous 

liquid, and that a first attempt to repair 

leaking equipment be made within 1 

hour of the time it is identified. The 

proposed rule would require that 

leaking equipment be repaired within 4 

hours of the time it is identified, 

although there are provisions for 

delaying repair of leaking equipment for 

up to 48 hours. 

Inspections for hydrogen gas leaks 

would be required twice per day (once 

each 12 hours). For a hydrogen leak at 

any location upstream of a hydrogen 

header, a first attempt at repair would 

be required within 1 hour of detection 

of the leaking equipment, and the 

leaking equipment would need to be 

repaired within 4 hours (with 

provisions for delay of repair if the 

leaking equipment is isolated). For a 

hydrogen leak downstream of the 

hydrogen header but upstream of final 

control, a first attempt at repair would 

be required within 4 hours, and 

complete repair would be required 

within 24 hours (with delay provisions 

if the header is isolated). 

As a complement to the inspection 

program, the proposed rule also 

includes a requirement to institute a cell 

room monitoring program whereby 

owners and operators would 

continuously monitor mercury 

concentration in the upper portion of 

each cell room and take corrective 

actions as soon as practicable when 

elevated mercury vapor levels are 

44678 Federal Register / Vol. 67, No. 128 / Wednesday, July 3, 2002 / Proposed Rules 

detected. The proposed rule does not 

include detailed requirements for this 

program. However, we do plan to 

develop specific criteria for such a 

program which would be issued either 

as guidance outside of the final rule or 

as an amendment to the final rule.

The program would not be a 

continuous monitoring system 

inasmuch as the results would be used 

only to determine relative changes in 

mercury vapor levels rather than 

compliance with a cell room emission 

or operating limit. Generally, the owner 

or operator would need to establish an 

action level for each cell room which 

would be based on preliminary 

monitoring to determine normal 

baseline conditions. The action level, or 

levels if appropriate, would then be 

established as a yet to be determined 

multiple of the baseline values. Once 

the action level(s) is established, 

continuous monitoring would need to 

be conducted. If an action level is 

exceeded, actions to correct the 

situation would need to be initiated as 

soon as possible. If the elevated mercury 

vapor level is due to a maintenance 

activity, the owner or operator would 

need to ensure that all work practices 

related to that maintenance activity are 

followed. If a maintenance activity is 

not the cause, inspections and other 

actions would be needed to identify and 

correct the cause of the elevated 

mercury vapor level. 

For fugitive mercury emissions 

associated with storage areas for 

mercury-containing waste, the proposed 

rule would require that carbon media 

from decomposers and cell room 

sludges either be stored in closed 

containers or be stored in open 

containers under a layer of aqueous 

liquid that is replenished at least once 

per week. For all other mercurycontaining wastes, the proposed rule 

would require that the wastes either be 

washed or chemically decontaminated 

to remove visible mercury or be stored 

in closed containers. 

Finally, the proposed rule would 

establish the duty for owners and 

operators to routinely wash surfaces 

throughout the plant where liquid 

mercury could accumulate. Owners and 

operators would be required to prepare 

and follow a written washdown plan 

detailing how and how often specific 

areas specified in the proposed rule 

would be washed down to remove any 

accumulations of liquid mercury. 

E. What Are the Operation and 

Maintenance Requirements? 

We are proposing that each owner and 

operator would always operate and 

maintain affected source(s), including 

air pollution control and monitoring 

equipment, in a manner consistent with 

good air pollution control practices at 

least to the levels required by the 

proposed rule, as required under 

§ 63.6(e)(1)(i) of the NESHAP General 

Provisions. The proposed rule would 

require each owner and operator to 

prepare and implement a written 

startup, shutdown, and malfunction 

plan according to the operation and 

maintenance requirements in 

§ 63.6(e)(3) of the NESHAP General 

Provisions. 

F. How Are Initial and Continuous 

Compliance With the Emission 

Limitations To Be Demonstrated?

The proposed rule would require 

compliance with emission limitations 

within 2 years from [DATE OF 

PUBLICATION OF THE FINAL RULE 

IN THE Federal Register]. 

To demonstrate initial compliance 

with the proposed emission limits for 

by-product hydrogen streams and endbox ventilation system vents, we are 

proposing that each owner and operator 

would conduct performance tests and 

perform specified calculations. A test 

would be needed for each by-product 

hydrogen stream using 40 CFR part 61, 

appendix A, Method 102. A test would 

also be required for each end-box 

ventilation system vent using 40 CFR 

part 61, appendix A, Method 101 or 

101A. Each performance test would be 

conducted in accordance with a sitespecific test plan prepared pursuant to 

the performance test quality assurance 

program requirements in § 63.7(c)(2) of 

the NESHAP General Provisions. Each 

performance test would be comprised of 

at least three runs, each lasting 2 hours 

at a minimum. Concurrent with each 

test run, the quantity of chlorine 

produced would need to be determined 

according to an equation contained in 

the proposed rule that calculates 

chlorine production based on cell line 

electric current load. Then, the mass of 

mercury emitted per unit mass of 

chlorine produced would be calculated 

for each test run, and the runs would be 

averaged for each tested vent. Initial 

compliance would be achieved if the 

sum of the average mass of mercury 

emitted per mass of chlorine produced 

of all by-product hydrogen streams and 

all end-box ventilation system vents is 

less than 0.067 gm Hg/Mg Cl2 for plants 

with end-box ventilation systems, or if 

the sum of the average mass of mercury 

emitted per mass of chlorine produced 

of all by-product hydrogen streams is 

less than 0.033 gm Hg/Mg Cl2 for plants 

without end-box ventilation systems. 

To demonstrate initial compliance 

with the mercury thermal recovery unit 

emission limits, we are proposing that a 

performance test be conducted for each 

vent using Method 101 or 101A. Once 

again, the performance test would need 

to follow a site-specific test plan 

developed by the owner and operator 

according to § 63.7(c)(2) of the NESHAP 

General Provisions. The proposed rule 

would require that during the test, the 

type of waste resulting in the highest 

mercury concentration in the mercury 

thermal recovery unit vent be processed. 

Documentation of the mercury content 

of this type of waste and an explanation 

of why it results in the highest mercury 

concentration would be required as part 

of the site-specific test plan. Three test 

runs would need to be conducted at a 

point after the last control device for 

each vent. Initial compliance would be 

achieved if the average vent mercury 

concentration is less than 23 mg/dscm 

for each oven type vent or 4 mg/dscm 

for each non-oven type vent.

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. This operating limit would be 

established during the required 

performance tests, as explained later in 

this section. Continuous compliance 

would be demonstrated by collecting 

outlet elemental mercury concentration 

data using a 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. 

The proposed rule would require that 

each continuous mercury vapor monitor 

be installed, operated, and maintained 

in accordance with a site-specific 

monitoring plan. For each monitor, this 

plan would need to address installation 

and siting, monitor performance 

specifications, performance evaluation 

procedures and calibration criteria, 

ongoing operation and maintenance 

procedures, ongoing data assurance 

procedures, and ongoing recordkeeping 

and reporting procedures. 

Owners or operators would establish 

a mercury concentration operating limit 

for each by-product hydrogen stream, 

end-box ventilation system vent, and 

mercury thermal recovery unit vent as 

part of the initial compliance 

demonstration. During each 

Federal Register / Vol. 67, No. 128 / Wednesday, July 3, 2002 / Proposed Rules 44679

performance test, the proposed rule 

would require that a continuous 

mercury vapor monitor be used to 

measure elemental mercury 

concentration in the vent stream at least 

once every 15 minutes for the entire 

duration of each performance test run. 

The average elemental mercury 

concentration measured during any 

valid test run conducted during the 

performance test in which mercury 

emissions did not exceed the applicable 

emission limit would then be 

established as the mercury 

concentration operating limit. 

G. How Are Initial and Continuous 

Compliance With the Work Practice 

Standards To Be Demonstrated? 

The proposed rule would require 

compliance with the work practice 

standards within 2 years from [DATE 

OF PUBLICATION OF THE FINAL 

RULE IN THE Federal Register]. The 

proposed work practice standards 

would primarily be requirements for 

ongoing operational activities. For these 

activities, there is no specific action 

called for to demonstrate initial 

compliance, other than a commitment 

by the owner or operator that the work 

practices standards will be met. 

Therefore, the major component of the 

initial compliance demonstration for the 

work practice standards would be a 

certification by the owner or operator 

that the work practice standards will be 

met. In addition, there are a few 

requirements that could cause an owner 

or operator to install new equipment or 

upgrade existing equipment. 

Documentation of any such actions 

would also be required in the initial 

compliance demonstration. 

The proposed rule contains specific 

recordkeeping requirements related to 

the work practice standards. These 

include records of when inspections 

were conducted, problems identified, 

and actions taken to correct problems. 

Continuous compliance with work 

practice standards would be 

demonstrated by maintaining these 

required records. 

Initial compliance with the 

washdown plan would be demonstrated 

by submission of the plan by the owner 

or operator and certification that they 

operate according to, or will operate 

according to, the plan. Continuous 

compliance with the plan would be 

demonstrated by maintaining related 

records. Records would also be required 

to demonstrate compliance with the cell 

room monitoring program. 

H. What Are the Notification and 

Reporting Requirements? 

The proposed rule would require that 

owners or operators submit the 

following notifications and reports: 

• Initial Notification

• Notification of Intent to conduct a 

performance test 

• Notification of Compliance Status 

(NOCS) 

• Compliance reports. 

For the Initial Notification, we are 

proposing that each owner or operator 

notify us that their plant is subject to the 

NESHAP for mercury cell chlor-alkali 

plants, and that they provide other basic 

information about the plant. For existing 

sources, this notification would need to 

be submitted no later than [DATE 120 

CALENDAR DAYS AFTER 

PUBLICATION OF THE FINAL RULE 

IN THE Federal Register]. 

For the Notification of Intent report, 

we are proposing that each owner or 

operator notify us in writing of the 

intent to conduct a performance test at 

least 60 days before the performance test 

is scheduled to begin. 

The Notification of Compliance Status 

for the work practice standards would 

be due [DATE 30 DAYS AFTER THE 

PUBLICATION OF THE FINAL RULE 

IN THE Federal Register] for existing 

sources. In this notification, the owner 

or operator would need to certify that 

the work practice standards are being or 

will be met. Furthermore, we are 

proposing that the washdown plan be 

submitted as part of this notification, 

and that the owner or operator certify 

that they operate or will operate 

according to the plan. 

For the emission limits where a 

performance test is required to 

demonstrate initial compliance (that is, 

the emission limits for by-product 

hydrogen streams and end-box 

ventilation system vents and the 

mercury thermal recovery unit vent 

limits), the tests would have to be 

conducted within 180 days after the 

compliance date, and the Notification of 

Compliance Status would be due 60 

days after the completion of the 

performance test. We are proposing that 

the site-specific plan addressing the use 

of continuous mercury vapor monitors 

for vents be submitted as part of this 

notification. 

Reporting on continuous compliance 

would be required semiannually, with 

the first report due within the first 6 

months after initial compliance. 

I. What Are the Recordkeeping 

Requirements? 

Records required by the proposed rule 

related to by-product hydrogen streams, 

end-box ventilation system vents, and 

mercury thermal recovery unit vents 

include the following: performance test 

results, records showing the 

establishment of the applicable mercury 

concentration operating limits 

(including records of the mercury 

concentration monitoring conducted 

during the performance tests), records of 

the continuous mercury concentration 

monitoring data, records of the daily 

average elemental mercury 

concentration values, and records 

associated with site-specific monitoring 

plans.

With regard to the work practice 

standards, the proposed rule would 

require that records be maintained to 

document when each required 

inspection was conducted and the 

results of each inspection. Records 

noting equipment problems (such as 

end-box cover stoppers not securely in 

place or mercury in an open container 

not covered by an aqueous liquid) 

identified during a required inspection 

and the corrective action taken would 

also be required. If equipment that is 

leaking mercury liquid or hydrogen/

mercury vapor is identified during a 

required inspection or at any other time, 

the proposed rule would require records 

of when the leak was identified and 

when it was repaired. Similarly, if a 

mercury spill or accumulation is 

identified at any time, the proposed rule 

would require records of when the spill 

or accumulation was found and when it 

was cleaned up. 

A copy of the current version of the 

washdown plan would need to be kept 

on-site and be available for inspection. 

Records of when washdowns were 

conducted would be required. 

The proposed rule would require that 

copies of each notification and report 

that is submitted to comply with this 

subpart be kept and maintained for 5 

years, the first 2 of which must be onsite. 

III. Rationale for Selecting the Proposed 

Standards 

A. How Did We Select the Source 

Category? 

The mercury cell chlor-alkali 

production portion of the chlorine 

production source category was among 

the categories and subcategories of 

major and area sources listed for 

regulation under section 112(c)(6) of the 

CAA (63 FR 17838, April 10, 1998) to 

assure that sources accounting for not 

less than 90 percent of the aggregate 

mercury emissions nationwide are 

subject to standards under section 

112(d). We estimate that mercury cell 

chlor-alkali production accounts for 

44680 Federal Register / Vol. 67, No. 128 / Wednesday, July 3, 2002 / Proposed Rules 

over 5 percent of all stationary source 

emissions of mercury and over 25 

percent of the emissions from stationary 

noncombustion sources. The Chlorine 

Production source category is comprised 

of 43 facilities engaged in the 

manufacture of chlorine and caustic in 

electrolytic cells. Cell types employed 

include the diaphragm cell, membrane 

cell, and mercury cell. Of these, only the 

mercury cell process has the potential to 

emit mercury. For the 1997 base year of 

the MACT analysis, twelve facilities 

employed mercury cells. We are aware 

that one of the twelve facilities ceased 

operations permanently in September 

2000. Nonetheless, we considered it to 

be part of the source category for the 

development of MACT since it was in 

operation in 1997. 

B. How Did We Select the Affected 

Sources and Emission Points To Be 

Regulated?

For the purposes of implementing 

NESHAP, an affected source is defined 

to mean the stationary source, the group 

of stationary sources, or the portion of 

a stationary source that is regulated by 

relevant standards or other requirements 

established under section 112 of the 

CAA. An affected source specifies the 

group of unit operations, equipment, 

and emission points that are subject to 

the standards. We can define an affected 

source as narrowly as a single piece of 

equipment or as broadly as all 

equipment at a plant site. 

We decided to separate the unit 

operations and emission points related 

to the production of chlorine and 

caustic from the unit operations and 

emissions points related to mercury 

recovery. Mercury cell chlor-alkali 

production facilities include a number 

of integrated operations dedicated to the 

production, storage, and transfer of 

product chlorine, product caustic, and 

by-product hydrogen. In contrast, 

mercury recovery facilities are 

operations dedicated to the recovery of 

mercury from mercury-containing 

wastes. These operations are 

independent of the chlor-alkali process 

and are thus not integral to production. 

As a result, the proposed rule addresses 

emissions from two separate affected 

sources: mercury cell chlor-alkali 

production facilities and mercury 

recovery facilities. 

Unit operations and emission points 

grouped within the mercury cell chloralkali production facilities affected 

source are by-product hydrogen streams, 

end-box ventilation system vents, and 

fugitive mercury emissions associated 

with cell rooms, hydrogen systems, 

caustic systems, and storage areas for 

mercury-containing wastes. As 

described previously, each is a 

potentially significant source of mercury 

emissions. Chlorine purification, brine 

preparation, and wastewater treatment 

operations are believed to have low 

mercury emissions to the air. 

Accordingly, today’s proposal contains 

no requirements for these operations. 

Unit operations and emission points 

grouped within the mercury recovery 

facilities affected source include all 

mercury thermal recovery unit vents 

and fugitive mercury emissions 

associated with mercury-containing 

waste storage areas. Chemical mercury 

recovery and recovery in a batch 

purification still are believed to have 

low mercury emissions to the air. 

Accordingly, today’s proposal contains 

no requirements for these operations. 

C. How Did We Select the Form of the 

Standards? 

Section 112 of the CAA requires that 

standards be specified as numerical 

emission standards, whenever possible. 

However, if it is determined that it is 

not feasible to prescribe or enforce a 

numerical emission standard, section 

112(h) indicates that a design, 

equipment, work practice, or 

operational standard may be specified. 

With the exception of standards for 

fugitive emission sources, we are 

proposing numerical emission limits for 

all other mercury emission sources. 

Specifically, the proposed standards 

include numerical emission limits for 

by-product hydrogen streams, end-box 

ventilation system vents, and mercury 

thermal recovery unit vents. 

Cell rooms bring together mercury, a 

large electrical load, and hot production 

equipment. Accordingly, most fugitive 

mercury emission sources at mercury 

cell chlor-alkali plants are associated 

with cell rooms. Reliable quantification 

of these cell room fugitive emissions 

would be costly, owing to the need to 

measure both mercury vapor 

concentration and air flow rate at ceiling 

apertures with sophisticated equipment. 

Some plants have many separate ceiling 

apertures, and plants in warm climates 

tend to be little enclosed on the sides. 

Moreover, levels of fugitive mercury 

vary with cell room operations, 

precluding the setting of a numerical 

limit. 

Mercury cell chlor-alkali plant 

fugitive mercury emission sources are 

also associated with storage areas for 

mercury-containing wastes. The 

measurement of mercury emissions 

from mercury-containing waste storage 

areas is also impracticable as these are 

usually located in several places 

throughout a plant, many of which are 

open areas. 

Not unexpectedly, emissions data on 

cell room and waste storage emissions 

are very limited as in the case of cell 

rooms, or nonexistent as in the case of 

waste storage areas. As such, we believe 

that it is not feasible to either prescribe 

or enforce numerical emission limit(s) 

for fugitive mercury emissions from cell 

rooms and waste storage areas. 

Consequently, today’s proposed 

standards address fugitive emission 

sources at mercury cell chlor-alkali 

plants through the establishment of 

work practice standards. 

D. How Did We Determine the Basis and 

Level of the Proposed Standards for 

Existing Sources? 

Section 112 of the CAA establishes a 

minimum baseline or ‘‘floor’’ for MACT 

standards. For new sources, the 

standards for a source category or 

subcategory cannot be less stringent 

than the emission control that is 

achieved in practice by the bestcontrolled similar source. The standards 

for existing sources may be less 

stringent than standards for new 

sources, but they cannot be less 

stringent than the average emission 

limitation achieved by the bestperforming 12 percent of existing 

sources for categories and subcategories 

with 30 or more sources, or the average 

emission limitation achieved by the 

best-performing five sources for 

categories or subcategories with fewer 

than 30 sources for which the 

Administrator has emissions 

information.

After the floor has been determined 

for a category or subcategory, the 

Administrator must set MACT standards 

that are technically achievable and no 

less stringent than the floor. Such 

standards must then be met by all 

sources within the category or 

subcategory. The regulatory alternatives 

selected for new and existing sources 

may be different because of different 

MACT floors, and separate emission 

limits may be established for new and 

existing sources. 

The EPA generally determines the 

MACT floor and then considers beyondthe-floor control options. Here, EPA 

considers the achievable reductions in 

emissions of HAP (and possibly other 

pollutants that are co-controlled), cost 

and economic impacts, energy impacts, 

and other non-air environmental 

impacts. The objective is to achieve the 

maximum degree of HAP emission 

reduction without incurring 

unreasonable cost or other impacts. 

Federal Register / Vol. 67, No. 128 / Wednesday, July 3, 2002 / Proposed Rules 44681

1. By-Product Hydrogen Streams and 

End-Box Ventilation System Vents 

The fundamental unit in the mercury 

cell chlor-alkali process is a mercury 

cell. The by-product hydrogen stream 

and the end-box ventilation system vent 

represent the mercury emission point 

sources that originate from a mercury 

cell. As discussed earlier, hydrogen gas 

is incidentally produced as a result of 

the catalyzed reaction of sodium/

mercury amalgam and deionized water 

to produce caustic in a decomposer. The 

end-box ventilation stream is a 

collection of vapors from head spaces of 

end boxes and possibly other vessels, 

including pump tanks and seal legs, 

wash water tanks, and caustic tanks and 

headers. The mercury content of the byproduct hydrogen stream and the endbox ventilation stream, prior to control, 

is a direct function of the design of the 

mercury cell. Ten different mercury cell 

models are used by the twelve mercury 

cell chlor-alkali plants. Given these 

differences in cell design and their 

effect on potential vent mercury 

emissions, we opted to develop a cellwide standard for mercury emissions 

from both points. 

Given the large variation among the 

plants in terms of production capacity 

(the largest plant is capable of 

producing over five times as much 

chlorine as the smallest) and mercury 

emissions potential, we concluded that 

any equitable assessment of MACT 

should account for this disparity. We 

selected the actual amount of chlorine 

produced by weight as the uniform 

parameter for our analysis for the 

following reasons: Chlorine is the 

primary product generated; chlorine 

production can be accurately 

determined; and chlorine and hydrogen 

are generated in the same stoichiometric 

quantities, that is one molecule of 

hydrogen is produced for each molecule 

of chlorine produced. 

We then considered the fact that two 

plants do not have end-box ventilation 

systems. Both plants operate cells with 

closed end boxes. Consequently, there is 

no need for end-box ventilation and, 

therefore, no end-box ventilation system 

emission point. Next, we examined 

whether the mercury cells at the ten 

plants equipped with end-box 

ventilation systems could be 

reconfigured with closed end boxes. We 

concluded that the use of an end-box 

ventilation system is an inherent feature 

of the original design of a cell, and that 

it is not technically feasible to eliminate 

end-box ventilation systems at these 

plants. We have, therefore, decided to 

distinguish plants with end-box 

ventilation systems and plants without 

these systems for purposes of 

establishing MACT. 

Accordingly, we are proposing, for 

plants with end-box ventilation systems, 

a single emission limit for mercury 

emissions from all by-product hydrogen 

streams and mercury emissions from all 

end-box ventilation system vents in 

units of mass of mercury emissions per 

mass of chlorine produced. For plants 

without end-box ventilation systems, we 

are proposing an emission limit for 

mercury emissions from all by-product 

hydrogen streams in units of mass of 

mercury emissions per mass of chlorine 

produced.

• Emission Limit for Plants With EndBox Ventilation Systems 

In order to establish MACT for the 

combined mercury emissions from byproduct hydrogen streams and end-box 

ventilation system vents, we relied on 

estimates of annual mercury emissions 

for each vent and information on annual 

chlorine production provided by the ten 

plants with end-box ventilation systems. 

A total of twenty mercury emission 

estimates were provided, one emission 

estimate for all by-product hydrogen 

streams and one emission estimate for 

all end-box ventilation system vents at 

each of the ten plants. Background 

information on these emission estimates 

is available in the docket to this 

rulemaking (No. A–2000–32). 

Of the twenty emission estimates, 

fourteen (six for by-product hydrogen 

streams and eight for end-box 

ventilation system vents) are based on 

stack tests performed in accordance 

with established EPA reference methods 

specific to chlor-alkali plants. These 

include Method 101 for the 

determination of particulate and 

gaseous mercury from air streams (i.e., 

end-box ventilation system vents) and 

Method 102 for the determination of 

mercury in hydrogen streams. We 

obtained and reviewed copies of all 

available test reports and determined 

that the tests were conducted correctly. 

Six emission estimates (four for byproduct hydrogen streams and two for 

end-box ventilation system vents) are 

based on periodic measurements of 

mercury concentration in the vent 

streams. The methods used for these 

periodic measurements are largely 

modifications of EPA reference test 

methods. As such, we believe that they 

provide reasonably accurate results 

consistent with what would otherwise 

be obtained with the EPA reference test 

methods. Our conclusion is that these 

data represent the best information 

available on mercury emissions from 

these vents, and that they are 

appropriate for use in establishing 

MACT. 

The MACT floor was calculated as 

follows. For each plant, we divided the 

sum of the reported annual mercury 

emissions from all by-product hydrogen 

streams and end-box ventilation system 

vents by the annual chlorine 

production. The chlorine production 

values used are largely representative of 

actual annual chlorine production 

levels. We then ranked the plants from 

lowest to highest emitters for combined 

normalized mercury emissions. The 

normalized mercury emission values 

range from 0.067 grams Hg/Mg Cl2 to 

3.41 grams Hg/Mg Cl2. We should note 

that the lowest value, 0.067 grams Hg/

Mg Cl2, is from the plant that closed 

permanently in September 2000. 

Nonetheless, we believe that it is 

appropriate to retain it in the pool of 

existing sources used to determine 

existing source MACT. Prior to closure, 

this plant was the lowest-emitting and 

best-performing source. The average 

(mean) of the best (lowest) five 

normalized values results in a floor 

value for existing sources of 0.14 grams 

Hg/Mg Cl2. 

Of the ten plants with by-product 

hydrogen streams and end-box 

ventilation systems, we project that 

seven would need to install additional 

controls or upgrade existing controls to 

meet the 0.14 grams Hg/Mg Cl2 floor 

level. We assume the following plantspecific actions: Two plants would need 

to install new carbon adsorbers on their 

by-product hydrogen streams (one plant 

would be replacing an existing adsorber 

with a new, larger adsorber); one plant 

would need to install a new packed 

scrubber on its end-box ventilation 

system vent; three plants would need to 

install new controls on both their byproduct hydrogen streams and end-box 

ventilation system vents; and one plant 

would need to both upgrade carbon 

adsorber control on its by-product 

hydrogen stream by switching to 

impregnated carbon and replacing 

carbon more frequently as well as install 

a new packed scrubber on its end-box 

ventilation system vent. 

We estimate that the total aggregate 

installed capital control costs needed to 

meet the existing source MACT floor for 

the seven affected plants to be about 

$660,000. We estimate total aggregate 

annual control costs, including costs for 

labor, materials, electricity, capital 

recovery, taxes, insurance, and 

administrative charges (excluding costs 

for monitoring, reporting, and 

recordkeeping) for the seven affected 

plants to be about $570,000 per year. 

Mercury emission reductions against 

actual emissions would total 556 kg/yr 

(1,225 lbs/yr) for the seven affected 

plants. Mercury emission reductions 

44682 Federal Register / Vol. 67, No. 128 / Wednesday, July 3, 2002 / Proposed Rules 

against the potential-to-emit baseline, as 

represented by the allowable emissions 

under the Mercury NESHAP, would 

total over 3,400 kg/yr (over 7,500 lbs/yr) 

for the seven affected plants. The 

associated annual cost per unit of 

mercury emission reduction values 

would be approximately $465 per 

pound (actuals baseline) and under $80 

per pound (potential-to-emit baseline), 

respectively. 

Water pollution impacts due to the 

increased use of packed bed scrubbers 

involving aqueous hypochlorite 

scrubbing solution on end-box 

ventilation systems are estimated to 

total 1.2 million liters (320 thousand 

gallons) of additional wastewater. 

Impacts on solid waste due to increased 

use of carbon adsorption for by-product 

hydrogen streams are estimated to total 

17 megagrams per year (Mg/yr), 19 tons 

per year (tpy), of mercury-containing 

spent carbon. Energy requirements are 

estimated to total an additional 878 

thousand kilowatt-hours per year (kWhr/yr). Estimated secondary air 

pollution impacts due to heightened 

energy consumption total 282 Mg/yr 

(311 tpy), with carbon dioxide 

emissions comprising 99 percent of the 

estimate.

We then examined beyond-the-floor 

MACT options. We selected the lowest 

normalized value among the ten plants, 

namely 0.067 grams Hg/Mg Cl2, as a 

beyond-the-floor option. As noted 

above, this 0.067 grams Hg/Mg Cl2 value 

is from a plant that is now closed. 

Nonetheless, as stated previously, we 

believe it is appropriate to retain it in 

the pool of existing sources and to 

include it in the beyond-the-floor 

assessment. 

The 0.067 grams Hg/Mg Cl2 value 

corresponds to 0.05 grams Hg/Mg Cl2

from the by-product hydrogen stream 

controlled by a condenser coupled with 

a molecular sieve adsorber, and 0.017 

grams Hg/Mg Cl2 from the end-box 

ventilation system vent, also controlled 

by a condenser coupled with a 

molecular sieve adsorber. It is our 

understanding that molecular sieve 

technology for mercury vapor emission 

control is no longer commercially 

available. We, thus, acknowledge some 

uncertainty associated with the 

achievability of this level of control. 

However, for the reasons set forth 

below, we believe that other 

technologies and operating practices 

exist that can achieve this level of 

emissions control. 

Due to the very low volumetric flow 

rates associated with both by-product 

hydrogen streams and end-box 

ventilation system vents (typically less 

than 5,000 scfm and 4,500 scfm, 

respectively), we believe that the retrofit 

of control equipment to reduce mercury 

emissions is both practical and 

reasonable. We project that the nine 

plants with baseline emissions greater 

than 0.067 grams Hg/Mg Cl2 would meet 

the 0.067 grams Hg/Mg Cl2 beyond-thefloor option through the installation of 

new controls or the upgrading of 

existing controls. We assume the 

following plant-specific actions: two 

plants would need to install new carbon 

adsorbers on their by-product hydrogen 

streams (one plant would be replacing 

an existing adsorber with a new, larger 

adsorber); three plants would need to 

install a new packed scrubber on their 

end-box ventilation system vents; three 

plants would need to install new 

controls on both their by-product 

hydrogen streams and end-box 

ventilation system vents; and one plant 

would need to both upgrade existing 

carbon adsorber control on its byproduct hydrogen stream by switching 

to impregnated carbon and replacing 

carbon more frequently as well as install 

a new packed scrubber on its end-box 

ventilation system vent. We project that 

the five new carbon adsorbers would 

need to accommodate a 25 percent 

higher carbon charge than assumed to 

meet the floor option. Upgrades to 

existing carbon adsorber control would 

involve more frequent carbon 

replacement than that assumed to meet 

the floor option. Five of the seven new 

packed scrubbers on end-box ventilation 

systems would need to be operated 

more efficiently than assumed to meet 

the floor option.

In evaluating regulatory options that 

are more stringent than the floor, we 

must consider the cost of achieving such 

emission reductions, and any non-air 

quality health and environmental 

impacts and energy requirements. The 

beyond-the-floor option would result in 

an additional 76 kg/yr (168 lb/yr) of 

total mercury emission reductions for 

the nine affected plants (a 48 percent 

incremental reduction from the floor 

option). For the nine affected plants, the 

incremental installed capital costs are 

estimated to total around $210,000, and 

the incremental annual costs are 

estimated to total around $150,000 per 

year. The incremental cost per unit of 

incremental mercury emission 

reduction is $900 per pound. 

The incremental water pollution 

impacts are estimated to total 550 

thousand liters (145 thousand gallons) 

of additional wastewater. The 

incremental solid waste impacts are 

estimated as 5.1 Mg/yr (5.6 tpy) of 

mercury-containing spent carbon in 

total. The incremental energy impacts 

are estimated as 110 thousand kW-hr/yr 

in total. The incremental secondary air 

pollution impacts are estimated to total 

35 Mg/yr (39 tpy), with carbon dioxide 

emissions comprising 99 percent of the 

estimate. 

We believe the additional emission 

reductions that would be achieved by 

the beyond-the-floor option are 

warranted. Further, we believe that the 

incremental costs of achieving such 

emission reductions, as well as 

incremental non-air environmental 

impacts and energy requirements, are 

reasonable for mercury. Therefore, we 

selected the 0.067 grams Hg/Mg Cl2

beyond-the-floor option as MACT for 

plants with end-box ventilation systems. 

If comments are received on this 

proposal that lead us to conclude that 

this level of control is unachievable, we 

retain the option of setting the standard 

at the next lowest normalized emission 

value. Accordingly, we have evaluated 

the impacts of an alternative 0.076 

grams Hg/Mg Cl2 mercury emission 

limit for plants with end-box ventilation 

systems. 

We project that the eight plants with 

baseline emissions greater than 0.076 

grams Hg/Mg Cl2 would need to install 

new controls or upgrade existing 

controls to meet this level. This would 

result in an additional 65 kg/yr (143 lb/

yr) of total mercury emission reductions 

for the eight affected plants (a 41 

percent incremental reduction) from the 

floor option. We assume the same plantspecific actions as those assumed to 

meet the 0.067 grams Hg/Mg Cl2 value, 

given the small difference in emission 

reductions at the two levels. For the 

eight affected plants, the incremental 

installed capital costs are estimated to 

total around $197,000, and the 

incremental annual costs are estimated 

to total around $125,000 per year. The 

incremental cost per unit of incremental 

mercury emission reduction is $875 per 

pound. 

The incremental water pollution 

impacts are estimated to total 317 

thousand liters (84 thousand gallons) of 

additional wastewater. The incremental 

solid waste impacts are estimated as 5.1 

Mg/yr (5.6 tpy) of mercury-containing 

spent carbon in total. The incremental 

energy impacts are estimated as 105 

thousand kW-hr/yr in total. The 

incremental secondary air pollution 

impacts are estimated to total 34 Mg/yr 

(37 tpy), with carbon dioxide emissions 

comprising 99 percent of the estimate. 

• Emission Limit for Plants Without 

End-Box Ventilation Systems 

In order to establish MACT for 

mercury emissions from by-product 

hydrogen streams for the two plants 

without end-box ventilation systems, we 

used estimates of annual mercury 

Federal Register / Vol. 67, No. 128 / Wednesday, July 3, 2002 / Proposed Rules 44683

emissions from by-product hydrogen 

streams and information on actual 

chlorine production provided by the 

two plants for 1997. Both emission 

estimates are based on periodic 

measurements of mercury concentration 

in the vent streams obtained using 

methods that are largely modifications 

of EPA reference test methods. 

Background information on these 

emission estimates is available in the 

docket to this rulemaking (No. A–2000–

32).

For each plant, we divided the 

reported annual mercury emissions 

from by-product hydrogen streams by 

the annual chlorine production. The 

normalized values are 0.033 grams Hg/

Mg Cl2 and 0.17 grams Hg/Mg Cl2. 

Although there are fewer than five 

sources from which to constitute a 

MACT floor, we opted to take the 

average (mean) of the two normalized 

values, resulting in 0.10 grams Hg/Mg 

Cl2 as the floor value for existing 

sources. We project that the higher 

emitting plant would need to upgrade 

existing controls to meet the 0.10 grams 

Hg/Mg Cl2 floor level. Specifically, the 

carbon in its existing carbon adsorbers 

would need to be replaced more 

frequently. There would be no capital 

costs as more frequent carbon media 

replacement is only a recurring annual 

cost estimated at $13,000 per year. 

Mercury emission reductions against 

actual emissions would total 6 kg/yr (14 

lbs/yr). Mercury emission reductions 

against the potential-to-emit baseline, as 

represented by the allowable emissions 

under the Mercury NESHAP, would 

total over 600 kg/yr (over 1,300 lbs/yr). 

The associated annual cost per unit of 

mercury emission reduction values 

would be approximately $940 per 

pound and less than $10 per pound, 

respectively. There are no associated 

secondary air pollution, water pollution, 

or energy impacts. Estimated solid 

waste impacts due to increased use of 

carbon adsorption total 1.0 Mg/yr (1.1 

tpy). 

We then examined beyond-the-floor 

MACT options. We selected the lowest 

normalized value among the two plants, 

namely 0.033 grams Hg/Mg Cl2, as a 

beyond-the-floor option. Controls 

applied to achieve this value include a 

condenser coupled with a carbon 

adsorber. For purposes of estimating 

impacts, we assumed that the higheremitting plant would replace its existing 

carbon adsorber with a new, larger 

adsorber to meet the 0.033 grams Hg/Mg 

Cl2 level. 

In evaluating regulatory options that 

are more stringent than the floor, we 

must consider the cost of achieving such 

emission reduction, and any non-air 

quality health and environmental 

impacts and energy requirements. The 

beyond-the-floor option would result in 

an additional 6 kg/yr (14 lb/yr) of total 

mercury emission reductions (a 47 

percent incremental reduction from the 

floor option). The incremental installed 

capital costs are estimated to total 

around $182,000. The incremental 

annual costs are estimated to total 

around $126,000 per year. The 

incremental cost per unit of incremental 

mercury emission reduction is 

approximately $9,000 per pound. There 

are no associated incremental water 

pollution impacts. The estimated 

incremental solid waste impacts total an 

additional 5.3 Mg/yr (5.8 tpy) of 

mercury-containing spent carbon. The 

incremental energy impacts are 

estimated as 252 thousand kW-hr/yr in 

total. The incremental secondary air 

pollution impacts are estimated to total 

81 Mg/yr (89 tpy), with carbon dioxide 

emissions comprising 99 percent of the 

estimate. 

We believe the additional emission 

reductions that would be achieved by 

the beyond-the-floor option are 

warranted. Further, we believe that the 

incremental costs of achieving such 

emission reductions as well as 

incremental non-air environmental 

impacts and energy requirements are 

reasonable for mercury. Therefore, we 

selected the 0.033 grams Hg/Mg Cl2

level as MACT for plants without endbox ventilation systems, which is 

approximately half the level selected for 

plants with end-box ventilation systems. 

2. Sources of Fugitive Mercury 

Emissions 

As explained above, we have 

determined that work practice standards 

provide the most appropriate approach 

for addressing fugitive mercury 

emissions at mercury cell chlor-alkali 

plants. Every mercury cell chlor-alkali 

plant is currently subject to the Mercury 

NESHAP and implements the design, 

maintenance, and housekeeping 

practices referenced in the NESHAP to 

control fugitive cell room emissions. We 

believe that these existing requirements 

represent the MACT floor for existing 

mercury fugitive emission sources. 

Since these floor requirements are 

currently observed at each existing 

plant, a standard based on this floor 

level of control would not be expected 

to reduce mercury emissions from 

current levels or produce any associated 

cost, non-air environmental or energy 

impacts.

We then examined beyond-the-floor 

options. We noted that many of the 

existing work practice requirements are 

general in nature and nonspecific 

relative to the frequency and scope of 

inspections, as well as recordkeeping 

and reporting. We decided that 

clarification and elaboration on these 

general practices was warranted to make 

them more explicit and to improve 

assurance of compliance. Accordingly, 

we initiated a thorough examination of 

specific measures employed across the 

industry to limit fugitive mercury 

emissions. 

In the summer of 1998, we conducted 

site visits to five mercury cell chloralkali plants to observe and document 

their design, operational, maintenance, 

housekeeping, and recordkeeping 

practices. The five plants were selected 

to provide a broad representation of 

ownership (the five plants are owned by 

five different companies) and different 

mercury cell models (mercury cells 

made by all three manufacturers and of 

varying sizes are represented). We also 

selected plants in different areas of the 

United States (U.S.) to account for 

geographical variations such as climate. 

In addition to the site visits, we 

obtained current standard operating 

procedures for mitigating sources of 

fugitive mercury emissions from all 

twelve plants. We used this knowledge 

and information to develop a detailed 

compilation of practices currently used 

across the industry to control fugitive 

mercury emissions. 

We used this compilation to identify 

explicit practices for each individual 

plant area, equipment type, and 

inspection procedure and assembled 

them as beyond-the-floor work practice 

requirements. We feel that the resulting 

work practice standards represent the 

most stringent practices applied in the 

industry. 

The types of enhancements from the 

MACT floor level requirements that are 

included in the beyond-the-floor option 

may be generally classified in three 

categories. First, the beyond-the-floor 

requirements add considerable 

specificity. The equipment and areas to 

be inspected are identified along with 

the required frequency of the 

inspections and the conditions that 

trigger corrective action. Response time 

intervals for when the corrective actions 

must occur are also included. Second, 

some types of inspections are required 

at more frequent intervals than required 

by the Mercury NESHAP (e.g., 

inspecting decomposers for hydrogen 

leaks once each 12 hours rather than 

once each day). Third, the beyond-thefloor option includes additional 

requirements not included in the floor 

level. The two most obvious examples 

are the detailed recordkeeping 

procedures and reporting provisions 

which are more fully developed than 

44684 Federal Register / Vol. 67, No. 128 / Wednesday, July 3, 2002 / Proposed Rules 

those in the Mercury NESHAP and the 

requirements for storage of mercurycontaining wastes.

Also included in the beyond-the-floor 

option is a requirement for owners and 

operators to develop and implement a 

plan for the routine washdown of 

accessible surfaces in the cell room and 

other areas. All plants currently wash 

down cell room surfaces regularly. 

However, due to plant-specific 

considerations, we are uncomfortable 

with issuing a specific set of 

requirements for washdowns that would 

apply at all plants. As a result, the 

beyond-the-floor option establishes the 

duty for owners or operators to prepare 

and implement a written plan for 

washdowns and identifies elements to 

be addressed in the plan. Although 

washdowns are an ongoing practice at 

all plants, we believe that including 

such a requirement in the beyond-thefloor option will elevate the importance 

of washdowns as part of an overall 

approach to reducing cell room fugitive 

emissions. 

As a final element of the beyond-thefloor option, we considered the extent to 

which measurement of ambient mercury 

levels in the cell room air should be 

incorporated. Currently, all mercury cell 

chlor-alkali plants periodically monitor 

mercury vapor levels at the cell room 

floor plane, in keeping with 

Occupational Safety and Health 

Administration (OSHA) standards for 

worker exposure to mercury. Typically, 

on a daily basis, a plant operator 

measures and records the mercury vapor 

level in the cell room. Some plants use 

technologies that measure the mercury 

vapor level at a single point, such as 

portable mercury vapor analyzers based 

on ultraviolet light absorption or gold 

film amalgamation detection. Plant 

operators using these technologies take 

readings at specified locations in the 

cell room. Other plants utilize 

procedures that provide an aggregate 

reading, such as chemical absorption 

into potassium permanganate solution 

followed by separate cold vapor atomic 

absorption analysis in a laboratory 

setting. This composite sample is most 

often obtained by a plant operator 

walking through the cell room with a 

small sampling pump. 

When a mercury vapor level above the 

OSHA personal exposure limit is 

measured, plant operators require the 

use of respirators in the area. They also 

take action to determine and eliminate 

the cause of the elevated mercury level. 

Given the fact that all plants conduct 

cell room mercury vapor measurements, 

we determined that it was appropriate 

to include requirements to conduct cell 

room monitoring as a means to identify 

and correct situations resulting in 

elevated mercury levels (and obviously, 

increased mercury emissions) as part of 

the beyond-the-floor option for fugitive 

mercury emission sources. We 

considered basing such a program on 

periodic measurement, which would 

correspond to the programs currently in 

place at mercury cell chlor-alkali plants. 

We also considered basing such a 

program on the continuous 

measurement of mercury vapor levels in 

the upper portions of the cell room. We 

are aware of technologies, including 

extractive, cold vapor spectroscopy 

systems and open-path, differential 

optical absorption spectroscopy 

systems, designed for such continuous 

monitoring applications. In August of 

2000, we studied cell room mercury 

vapor levels at a U.S. mercury cell 

chlor-alkali plant using both extractive 

and open-path technologies. In addition, 

we are aware of extractive systems 

currently in use in Europe for this 

purpose. 

Upon consideration of the benefits of 

periodic versus continuous monitoring 

of the cell room mercury vapor levels, 

we selected continuous monitoring as 

part of the proposed cell room 

monitoring program for the following 

reasons. First, we believe that 

continuous monitoring would identify 

hydrogen leaks or other situations that 

result in elevated mercury levels in the 

cell room much more promptly than 

periodic monitoring. If periodic 

monitoring was conducted on a daily 

basis, hours could pass before such a 

leak was detected. We also believe that 

the continuous monitoring of mercury 

vapor levels during maintenance 

activities would provide information to 

help plant operators refine and improve 

such maintenance activities to reduce 

mercury emissions. 

Finally, we believe that the 

monitoring on the cell room floor plane 

could fail to detect hydrogen leaks or 

other situations resulting in mercury 

vapor leaks that may occur at higher 

elevations. Continuous monitoring in 

the upper portion of the cell room 

would provide a representation of all 

areas of the cell room at all levels. 

Therefore, we have included a 

program involving the continuous 

monitoring of mercury vapor levels in 

the cell room as part of the beyond-thefloor option. We envision the basic 

elements for this program to be as 

follows. Each owner or operator would 

be required to install a mercury 

monitoring system in each cell room 

and continuously monitor the elemental 

mercury concentration in the upper 

portion of the cell room. The type of 

technology, whether an extractive, cold 

vapor spectroscopy system or an openpath, differential optical absorption 

spectroscopy system, would be at the 

discretion of the owner or operator, 

provided that performance criteria, such 

as a minimum detection limit, were met. 

A sampling configuration would be 

specified to acquire a composite 

measurement representative of the 

entire cell room air. For example, the 

sampling configuration may involve 

sampling at least three points along the 

center aisle of the cell room and above 

the mercury cells at a height sufficient 

to ensure representative readings.

For each cell room, the owner or 

operator would need to establish an 

action level which would be based on 

preliminary monitoring to determine 

normal baseline conditions. The onset 

and duration of this preliminary 

monitoring would be specified as well 

as guidelines for setting the action level. 

Continuous monitoring would 

commence after a specified time period 

following establishment of the action 

level and its documentation in a 

notification to us. A minimum data 

acquisition requirement would be 

established, such as a requirement to 

collect and record data for at least a 

certain percent of the time in any 6-

month period. 

Actions to correct the situation as 

soon as possible would be required 

when measurements above the action 

level were obtained over a defined 

duration, such as a certain number of 

consecutive measurements or an average 

over a certain time period above the 

action level. If the elevated mercury 

vapor level was due to a maintenance 

activity, the owner or operator would 

need to keep records describing the 

activity and verifying that all work 

practices related to that maintenance 

activity are followed. If a maintenance 

activity was not the cause, then 

inspections and other actions would 

need to be conducted within specific 

time periods to identify and correct the 

cause of the elevated mercury vapor 

level. 

In evaluating whether to establish the 

beyond-the-floor option as MACT, we 

looked at the incremental impacts on 

emissions, cost, energy, and other nonair effects. Relative to emissions, we 

firmly believe that although we are 

unable to actually quantify the 

reductions expected with the 

implementation of the beyond-the-floor 

option, substantial reductions would 

nonetheless occur. We know from 

experience and inference that the added 

scrutiny inherent in the suite of beyondthe-floor practices will of necessity 

result in fewer fugitive emissions. In 

considering the cost impacts of the 

Federal Register / Vol. 67, No. 128 / Wednesday, July 3, 2002 / Proposed Rules 44685

beyond-the-floor option, we attempted 

to estimate the cost associated with the 

equipment needed to carry out cell 

room monitoring as well as increased 

demand for labor and overhead needed 

to fully implement the proposed 

monitoring, inspection, recordkeeping, 

and reporting activities. We estimate the 

total installed capital costs needed to 

meet the beyond-the-floor option for 

fugitive mercury emissions to be around 

$663,000. We estimate the total annual 

costs to be around $840,000 per year, 

consisting of about $94,000 for 

annualized capital expenditure on 

mercury monitoring systems; about 

$736,000 per year for labor for 

monitoring, inspections, and 

recordkeeping, about $2,100 per year for 

mercury monitoring system utilities, 

and about $7,500 per year for mercury 

monitoring system replacement parts. 

We are unable to estimate increases in 

wastewater associated with washdown 

and cleanup activities for liquid 

mercury spills and accumulations as 

well as increases in solid waste since 

these would be highly plant-specific. 

Energy requirements for mercury 

monitoring systems are estimated to 

total an additional 53 thousand kW-hr/

yr. Estimated secondary air pollution 

impacts due to heightened energy 

consumption total 17 Mg/yr (19 tpy), 

with carbon dioxide emissions 

comprising 99 percent of the estimate. 

We believe the additional emission 

reductions that would be achieved by 

the beyond-the-floor option are 

warranted and that the estimated 

incremental costs to meet this level are 

reasonable. Therefore, we are selecting 

the beyond-the-floor work practice 

standards as MACT for fugitive mercury 

emission sources. 

With regard to the cell room 

monitoring program, we acknowledge 

that there are uncertainties associated 

with the use of mercury monitoring 

systems for continuous monitoring that 

can only be addressed through actual 

field validation. We are specifically 

requesting comment on the feasibility of 

using such systems for continuous 

monitoring to prompt corrective actions 

for elevated mercury vapor levels in the 

cell room. We are also requesting 

comment on the detailed elements of 

the cell room monitoring program 

which we are unable to delineate in its 

entirety at this time.

Following proposal, we will involve 

the public in defining this program. 

Specifically, we will enter into a joint 

effort with industry, monitoring 

instrument suppliers, and other 

interested parties, to detail the elements 

and requirements of this program. We 

will take additional appropriate 

rulemaking steps as necessary to fully 

implement this program, including 

assuring opportunity for industry and 

the public to comment. 

3. Mercury Thermal Recovery Unit 

Vents 

As previously discussed, nine of the 

twelve mercury cell chlor-alkali plants 

have mercury recovery processes. Six of 

the nine plants operate a thermal 

recovery unit in which mercurycontaining wastes are heated and the 

resulting mercury-laden off-gas is 

cooled and treated for mercury removal 

prior to being discharged to the 

atmosphere. Two plants recover 

mercury with a chemical process and 

one plant recovers mercury in a 

purification still; in both cases, mercury 

air emissions are believed to be low. 

In establishing MACT for mercury 

thermal recovery units, we obtained 

information from all six plants with 

these units. Each plant provided 

descriptions of its thermal recovery 

operation, including the types of wastes 

processed and the control devices 

applied. Where available, plants also 

provided results of performance testing 

or periodic sampling and an estimate of 

their mercury emissions. 

Each of the six plants operates one or 

more retorts (as part of its mercury 

thermal recovery unit) in which 

mercury-containing wastes are heated to 

a temperature sufficient to volatilize the 

mercury. The off-gas containing 

mercury vapor is then cooled in the 

mercury recovery/control system, 

causing the mercury to condense to 

liquid. The liquid mercury condensate 

is then collected from recovery devices 

for reuse in the mercury cells. The 

primary emission source is the mercury 

thermal recovery unit vent where off-gas 

that has passed through the recovery/

control system is discharged to the 

atmosphere. Retorts used include three 

basic designs: batch oven (three plants), 

rotary kiln (two plants), and single 

hearth (one plant). 

The batch ovens are D-tube retorts 

which are so named because each 

resembles an uppercase letter ‘‘D’’ on its 

side. Pans are filled with waste, 

typically around 10 cubic feet, and then 

placed into an oven. After inserting 

three or four pans, the oven door is 

closed and the retort is indirectly heated 

to about 1,000°F. The residence time 

varies from about 24 to 48 hours, 

depending on the type of waste being 

processed. While heating, the oven is 

kept under a vacuum and the mercury 

vapors are pulled into the mercury 

recovery/control system. After the cycle 

is completed, the unit is allowed to cool 

and the pans are then removed. 

The rotary kilns are long, refractorylined rotating steel cylinders in which 

the waste charge to be treated flows 

counter current to hot combustion gases 

used for heating. Wastes to be treated 

are conveyed into a ram feeder which 

inserts a waste charge into the kiln at 

regular intervals, typically about every 5 

minutes. Each is directly fired with 

natural gas and is heated to over 

1,300°F. The rotation of the kiln 

provides for mixing and transfer of the 

waste to the discharge end. The 

residence time is about 3 hours. The gas 

stream leaving the kiln passes through 

an afterburner where the temperature is 

increased to around 2,000°F to complete 

combustion reactions involving sulfur 

and carbon and then to a mercury 

recovery/control system. 

The single hearth retort is comprised 

of a vertically mounted, refractory lined 

vessel with a single hearth and a 

rotating rabble. Waste is charged onto 

the hearth through a charge door by way 

of a conveyor. Once charged, the 

conveyor is withdrawn, the charge door 

is closed, and the heating or treatment 

cycle begins. The waste is stirred by the 

rabble rake, which turns continuously, 

and is heated to around 1,350°F. The 

residence time, which ranges according 

to waste type, is typically much longer 

than for rotary kilns. Similar to rotary 

kilns, the gas stream leaving the hearth 

retort passes through an afterburner 

where the temperature is increased to 

around 2,000°F to complete combustion 

reactions involving sulfur and carbon 

and then to a mercury recovery/control 

system. 

As noted above, there are several 

important differences between the oven 

retorts and the non-oven (rotary kiln 

and single hearth) retorts related to 

operating temperature and residence 

time. There are also significant 

differences in the volumetric flow rates 

produced by the oven and the non-oven 

retorts. Oven retorts typically have 

volumetric flow rates around 100 scfm, 

which is an order of magnitude lower 

than flow rates for non-oven retorts 

which are around 1,000 scfm. Together, 

these differences can have a material 

impact on mercury concentration, mass 

flow rate of mercury, and other factors 

that influence mercury loadings to the 

recovery/control system. After 

evaluation of these technical and 

operational differences between oven 

retorts and non-oven retorts and their 

potential effect on emissions 

characteristics and control device 

applicability, we are proposing to 

distinguish between retort types for the 

purpose of establishing MACT.

With the exception of the plant with 

a single hearth retort that is controlled 

44686 Federal Register / Vol. 67, No. 128 / Wednesday, July 3, 2002 / Proposed Rules 

with a scrubber as the final control 

device, the recovery/control system at 

each plant consists of condensation and 

carbon adsorption for final mercury 

control. The amount and type of carbon 

adsorbent used in the fixed bed, 

nonregenerative carbon adsorbers varies 

among the five plants. One plant uses 

activated carbon, one uses iodineimpregnated carbon, and three use 

sulfur-impregnated carbon. We believe 

that each type is effective in removing 

mercury provided the adsorbent is 

replaced at a frequency appropriate to 

prevent breakthrough. 

In contrast, the plant with the single 

hearth retort utilizes a chlorinated brine 

packed-tower scrubber for final mercury 

control. In this scrubber, elemental 

mercury vapor is removed by 

chemically reacting with the chlorinated 

brine solution to form mercuric 

chloride, a nonvolatile mercury salt 

which is readily soluble in aqueous 

solutions. The resulting scrubber 

effluent is returned to the brine system 

causing the absorbed mercury to be 

recycled back to the mercury cells. 

Performance data for this brine scrubber 

system shows that the effectiveness is 

comparable to that of the condenser/

carbon adsorber systems used at the 

other five plants. 

While examining the performance 

capabilities of the condenser/carbon 

adsorber systems, we identified several 

factors that influence performance. We 

believe that a primary factor affecting 

mercury recovery and control is the 

temperature to which retort off-gas is 

cooled prior to entering the final control 

device. Because of the volatile nature of 

elemental mercury, temperature has a 

direct effect on the concentration of 

mercury vapor that can exist in a gas 

stream. For example, the concentration 

of mercury vapor that could exist in a 

gas stream at 50°F is 5 mg/m3, while the 

predicted concentration at 85°F is 30 

mg/m3, a six-fold increase. At 100°F, the 

concentration could potentially be over 

50 mg/m3. 

A key factor relative to the 

performance of carbon adsorbers is 

contact time. As noted previously, we 

believe that generally each of the carbon 

adsorbents presently used in the 

industry can effectively collect mercury 

vapor. However, it is essential for 

optimum performance that the contact 

time between the gas stream to be 

treated and the carbon adsorbent be long 

enough to allow for maximum 

adsorption. Consequently, design and 

operational factors such as carbon bed 

depth, sorbent particle size, and gas 

velocity have an appreciable impact on 

collection efficiency. Another key 

consideration is the frequency at which 

the adsorbent is replaced since the 

adsorbing capacity of any sorbent 

decreases as saturation and 

breakthrough are approached.

In assessing potential formats for a 

numerical emission limit, we 

considered a limit on emissions in a 

specified time period, a limit 

normalized on the amount of wastes 

processed, and an outlet mercury 

concentration limit. The amounts and 

types of wastes processed at each plant 

and among plants vary considerably. We 

believe, generally, that mercury 

emissions from the thermal recovery 

unit vent are proportional to the amount 

of mercury-containing wastes processed 

and the amount of mercury contained in 

these wastes. Therefore, we concluded 

that limiting emissions over a specified 

time period would unfairly impact 

plants that process larger amounts of 

wastes and/or wastes that contain more 

mercury. A mercury emission limit 

normalized on the amount of wastes 

processed would eliminate this 

inequity. However, given the wide 

variation in the mercury content of 

different types of wastes and the varying 

mix of waste types processed at 

different plants, we concluded that 

setting and enforcing such an emissions 

limit is impractical. 

Several factors influence the 

concentration of mercury in the thermal 

recovery unit vent exhaust. The most 

significant include the mercury content 

of the wastes being processed and the 

volumetric flow rate through the system. 

Volumetric flow rate is dependent on 

process rate, fuel usage, and the volume 

of combustion gas generated. The 

mercury concentration may also vary 

depending on the stage of the heating 

cycle. The mercury content of the 

exhaust stream leaving the condenser(s) 

or other type of cooling unit should 

remain relatively constant, provided 

that the outlet temperature is constant 

and the residence time is sufficient. 

Depending on the effectiveness of the 

carbon adsorber or brine scrubber, the 

mercury concentration would be further 

reduced. As a result, we conclude that 

concentration at the outlet of the final 

control device is the most meaningful 

and practical measure of the combined 

performance of each element of the 

mercury recovery/control system. 

Therefore, we have selected 

concentration for the format of the 

MACT standard for mercury thermal 

recovery units. 

Finally, we evaluated how, or if, the 

proposed standards should address 

different waste types; that is, should 

different emission limits be set for 

different waste types or should one limit 

be set for the waste type shown to be the 

highest emitting. We analyzed all the 

available data but were unable to 

ascertain any relationship between the 

type of waste (K106, D009 debris, or 

D009 nondebris) being treated during 

testing or sampling and the outlet 

mercury concentration measured across 

all plants. As a result, we are proposing 

an outlet mercury concentration limit 

that is neutral to the type of waste being 

processed. The analysis also influenced 

our decision on the proposed 

requirements for performance testing. 

We are proposing that testing be 

conducted during conditions 

representative of the most extreme, 

relative to potential mercury 

concentration, expected to occur under 

normal operation. While we would have 

preferred that the proposed rule specify 

the type of waste to be processed during 

testing, our inability to discern a 

relationship between waste type and 

outlet mercury concentration across 

plants prevented us from doing so. 

Therefore, the proposed rule would 

obligate owners and operators to process 

mercury-containing wastes that result in 

the highest vent mercury concentration 

during performance testing. 

In summary, our review and analysis 

of all the available information on 

mercury thermal recovery units leads us 

to the following conclusions: 

• Separate MACT emission limits 

should be developed for oven type and 

non-oven (rotary kiln and single hearth) 

type mercury thermal recovery units. 

• These emission limits should not 

distinguish among waste types 

processed. 

• Concentration is the appropriate 

format for the numerical emission 

limits. 

The following describes how we 

selected the proposed emission limits 

for oven type and non-oven type 

mercury thermal recovery units.

There are three plants that use oven 

retorts. All are owned and operated by 

the same company. One plant operates 

five ovens, another operates three ovens, 

and the third operates two ovens. 

Thermal recovery at all three plants is 

conducted between 6,000 to 7,000 hours 

per year. The amounts of waste 

processed and the amounts of mercury 

recovered range from 90 to almost 300 

tpy and from 3 to 20 tpy, respectively. 

At all three plants, the mercury-laden 

off-gas leaving the retort is cooled and 

treated for particulates and acid gases in 

a wet scrubber with caustic solution, 

followed by further cooling in a 

condenser. The cooled gas is then 

routed through one or more fixed-bed, 

nonregenerative carbon adsorbers before 

being discharged to the atmosphere. We 

conducted an evaluation of the mercury 

Federal Register / Vol. 67, No. 128 / Wednesday, July 3, 2002 / Proposed Rules 44687

recovery/control systems at all three 

plants, considering the condenser outlet 

temperature and the amount of carbon 

in the beds. 

The plant that ranked highest in this 

evaluation, which we consider to be the 

best-controlled plant, provided mercury 

emissions data (periodic sampling 

results) over 3 years. The other two 

plants were unable to provide emissions 

data. Therefore, data from this bestcontrolled plant were used to establish 

MACT. Since an emission limit based 

on the best-controlled plant would 

obviously be more stringent than the 

floor level, the selection of a level 

associated with the best-performing 

recovery/control system for this retort 

type clearly meets our statutory 

requirement regarding the minimum 

level allowed for NESHAP. 

This best-controlled plant has five 

ovens and two separate but identical 

mercury recovery/control systems. One 

treats the exhaust gas from three ovens 

while the other services two ovens. Each 

system is comprised of a wet scrubber 

and condenser, which cool the exhaust 

gases to around 70°F, followed by a 

carbon adsorber with about 700 pounds 

of activated carbon. Available test data 

for this plant consist of bimonthly 

measurements for 1997, 1998, and 1999 

on each stack. We reviewed the 

sampling method used to obtain these 

data which are largely based on EPA 

reference methods for mercury 

emissions from mercury cell chlor-alkali 

plants and concluded that it is capable 

of producing measurements of 

reasonable accuracy that are suitable for 

use as the basis for MACT. We removed 

six data points that we determined were 

statistical outliers and combined the 

data for both control systems into one 

data set comprised of 134 individual 

measurements. 

We then evaluated options for how 

these data should be used to establish a 

numerical emission limit to represent 

MACT. While this limit must represent 

the performance of the controls in place 

at this best-controlled plant, it also must 

account for variability in outlet mercury 

concentration due to processing 

different mercury-containing waste 

types and normal variation in recovery/

control equipment performance. As 

noted previously, we are proposing that 

performance tests for mercury thermal 

recovery units be conducted under the 

most challenging conditions, which we 

are defining as the processing of wastes 

that result in the highest recurring 

mercury concentration in the vent 

exhaust. Each performance test would 

consist of at least three runs, and the 

average concentration measured would 

be compared with the emission limit to 

determine compliance. Given our 

inability to establish a discernible 

correlation between waste type 

processed and emissions, our obligation 

to set standards that are achievable 

under the full range of normal 

acceptable operating conditions and the 

fact that initial performance is based on 

at least three separate test runs, we 

chose to set the standard based on the 

average of the three highest measured 

values in the data set of 134 

measurements for the best-controlled 

plant. The three measured values are 

20.4, 22.1, and 26.4 mg/m3. The average 

of the three is 23 mg/dscm, which we 

are proposing as the mercury 

concentration emission limit for oven 

type units.

Due to the very low volumetric flow 

rates associated with oven type mercury 

thermal recovery unit exhaust streams 

(typically less than 300 scfm), we 

believe that the retrofit of control 

equipment to reduce mercury emissions 

is both practical and reasonable. For 

purposes of estimating the impacts of 

the proposed emission limit, we 

assumed that the two plants with lowerperforming control systems would need 

to install new, larger carbon adsorbers to 

meet the 23 mg/dscm level. The total 

installed capital control costs are 

estimated to be around $217,000 for all 

three plants, and the total annual 

control costs are estimated to be around 

$163,000 per year for all three plants. 

Estimated mercury emission reductions 

against actual baseline emissions would 

total 33 kg/yr (74 lbs/yr) for all three 

plants. The associated annual cost per 

unit of mercury emission reduction 

would be approximately $2,200 per 

pound. 

Impacts on solid waste due to 

increased use of carbon adsorption are 

estimated total 5.2 Mg/yr (5.7 tpy) of 

mercury-containing spent carbon. 

Energy requirements are estimated to be 

an additional 473 thousand kW-hr/yr. 

Estimated secondary air pollution 

impacts due to heightened energy 

consumption are 152 Mg/yr (168 tpy), 

with carbon dioxide emissions 

comprising 99 percent of the estimate. 

As noted previously, three plants 

operate retorts other than oven-type 

retorts. Thermal recovery at these three 

plants is conducted between 1,500 and 

5,000 hours per year. The amounts of 

waste processed and the amounts of 

mercury recovered range from 50 to 500 

tpy and from 3 to 12 tpy, respectively. 

The mercury recovery/control systems 

operated at the two plants with rotary 

kiln retorts consist of direct contact 

cooling, particulate and acid gas 

scrubbing, condensation, and carbon 

adsorption. The retort off-gas at both 

plants is cooled to a temperature of 55°

F on average before being routed 

through two fixed-bed, nonregenerative 

adsorbers containing sulfur-impregnated 

carbon media. The mercury recovery/

control system at the plant with a single 

hearth retort employs a direct contact 

water quench tower, a venturi scrubber, 

and a caustic packed-tower scrubber, 

which lower the retort off-gas 

temperature to an average of 80° F, and 

a chlorinated brine packed-tower 

scrubber as the final control device. The 

following summarizes the emissions 

data available and our approach to 

determining MACT for non-oven type 

units. 

At one of the plants with a rotary kiln, 

the mercury concentration is 

determined daily at the outlet of the last 

carbon adsorber bed using a companydeveloped procedure derived from an 

OSHA method for determining worker 

exposures in the workplace. When 

submitting data obtained using this 

method, the company cautioned that 

although the routine sampling with the 

modified OSHA procedure produces 

credible information on relative changes 

in performance, it does not produce 

accurate information on actual mercury 

releases. Specifically, we believe the 

data obtained using this method are 

biased low. The average measured 

mercury concentration for this plant is 

an order of magnitude lower than 

averages for the other two plants 

(discussed below), and the minimum 

measured value is two orders of 

magnitude lower. It is our conclusion 

that data from this plant are unsuitable 

for standard setting, as they greatly 

understate emissions and thus overstate 

the performance of the mercury 

recovery/control system. 

At the other plant with a rotary kiln, 

concentration measurements are made 

monthly using a method that is a 

modification of EPA Method 101 for 

determining mercury emissions from 

mercury cell chlor-alkali plants. Data 

were provided for each month in 1998. 

The measured mercury concentrations 

range from 1.4 mg/m3 to 6.0 mg/m3, 

with a mean of 2.8 mg/m3. 

Personnel at the plant with the single 

hearth retort conduct monthly 

measurements of the mercury 

concentration in the brine scrubber 

exhaust gas. The measurement method 

used is based on an EPA reference 

method and is very similar to the 

method used at the second rotary kiln 

plant discussed above. Data were 

provided for 1997, 1998, and 1999. The 

measured mercury concentrations range 

from 0.2 mg/m3 to 10.8 mg/m3, with a 

mean and median value of 1.6 and 2.2 

mg/m3, respectively.

44688 Federal Register / Vol. 67, No. 128 / Wednesday, July 3, 2002 / Proposed Rules 

In establishing the MACT floor and 

subsequently MACT, we focused on the 

two plants for which we have credible 

emissions data. We removed two points 

determined to be statistical outliers from 

the 3-year data set at the plant with the 

single hearth retort and determined 

there were no statistical outliers in the 

1998 data set for the second plant with 

a rotary kiln. These data were used in 

the MACT determination for non-oven 

thermal recovery unit vents. 

Although there are fewer than five 

sources from which to constitute a 

MACT floor, we opted to take the mean 

of the data from these two plants as the 

MACT floor option for existing sources. 

We averaged the three highest 

concentration data points for each plant 

and took the mean of the two plant 

averages (3.9 mg/dscm and 5.4 mg/

dscm) rounded to one significant figure, 

5 mg/dscm, as the floor value. 

Of the three plants with non-oven 

type mercury thermal recovery unit 

vents, we project that only one plant 

would need to upgrade existing controls 

to meet the 5 mg/dscm floor level, and 

that this could be accomplished by 

replacing the carbon in its existing 

carbon adsorbers more frequently than 

current practice. There would be no 

capital costs as more frequent carbon 

media replacement is only a recurring 

annual cost estimated at $1,200 per 

year. Mercury emission reductions 

against actual baseline emissions would 

total about 2 kg/yr (5 lbs/yr) for the 

three plants. The associated annual cost 

per unit of mercury emission reduction 

would be approximately $240 per 

pound. With the assumption of more 

frequent carbon media replacement, 

there are no associated secondary air 

pollution, water pollution, or energy 

impacts. Estimated solid waste impacts 

due to increased use of carbon 

adsorption total 0.09 Mg/yr (0.1 tpy). 

We then examined beyond-the-floor 

MACT options. A direct comparison of 

the data for the two plants providing 

credible data indicates that the emission 

levels recorded at one plant (with mean 

and median values of 1.2 and 0.7 mg/

m3, respectively) are about half that 

recorded at the other plant (with mean 

and median values of 2.8 and 1.9 mg/

m3, respectively). Further, the highest 

monthly values recorded were 4.3 mg/

m3 and 5.9 mg/m3, respectively. We 

used the data from the lower-emitting 

plant to establish a beyond-the-floor 

option. We averaged the three highest 

values for this plant (not including the 

values determined to be outliers) for a 

beyond-the-floor value of 4 mg/dscm. 

Due to the very low volumetric flow 

rates associated with non-oven type 

mercury thermal recovery unit exhaust 

streams (typically less than about 2,000 

scfm), we believe that the retrofit of 

control equipment to reduce mercury 

emissions is both practical and 

reasonable. For purposes of estimating 

impacts, we assumed that one plant 

would need to upgrade its controls, and 

that it would do this by further 

increasing its carbon replacement 

frequency to meet the 4 mg/dscm level. 

We assume that the remaining plant 

would not need to upgrade its existing 

controls to meet the beyond-the-floor 

level. 

In evaluating regulatory options that 

are more stringent than the floor, we 

must consider the cost of achieving such 

emission reduction, and any non-air 

quality health and environmental 

impacts and energy requirements. The 

beyond-the-floor option would result in 

an additional 6 kg/yr (13 lbs/yr) of total 

mercury emission reductions for the 

three plants (a 10 percent incremental 

reduction from the floor option). The 

incremental annual costs are estimated 

to total around $5,800 per year. The 

incremental cost per unit of incremental 

mercury emission reduction is 

approximately $450 per pound. With 

the assumption of more frequent carbon 

media replacement, there are no 

associated incremental secondary air 

pollution, water pollution, or energy 

impacts. The estimated solid waste 

impacts total an additional 0.4 Mg/yr 

(0.5 tpy) of mercury-containing spent 

carbon. 

We believe the additional emission 

reductions that would be achieved by 

the beyond-the-floor option are 

warranted. Further, we believe that the 

incremental costs of achieving such 

emission reductions, as well as 

incremental non-air environmental 

impacts and energy requirements, are 

reasonable for mercury. Therefore, we 

selected 4 mg/dscm as MACT for nonoven type mercury thermal recovery 

unit vents. 

In summary, the proposed emission 

limits are 23 mg/dscm and 4 mg/dscm 

for oven type mercury thermal recovery 

unit vents and non-oven type mercury 

thermal recovery unit vents, 

respectively. We believe that both 

proposed limits are representative of the 

best-performing systems for each retort 

type based on available data and as 

such, each limit clearly meets our 

statutory safeguard regarding the 

minimum level of control allowed 

under the statute. 

E. How did We Determine the Basis and 

Level of the Proposed Standards for 

New Sources? 

Section 112(d)(3) of the CAA specifies 

that standards for new sources cannot 

be less stringent than the emission 

control that is achieved in practice by 

the best-controlled similar source, as 

determined by the Administrator. 

In the case of mercury cell chlor-alkali 

production facilities, of the 43 chloralkali production facilities in operation 

in the U.S. at the time of this analysis, 

32 use cell technologies other than 

mercury (23 use diaphragm cells and 9 

use membrane cells). As explained 

further below, we consider these chloralkali facilities using non-mercury cell 

technology to be ‘‘similar sources,’’ and, 

as such, a suitable basis for the standard 

for new source MACT. Such a standard 

would effectively eliminate mercury 

emissions from new source chlor-alkali 

production facilities.

The impact of such a standard would 

be negligible given that in terms of cost, 

economic and air and non-air 

environmental impacts, we don’t 

believe that a new mercury cell chloralkali plant would otherwise ever be 

constructed. No new mercury cell chloralkali plant has been constructed in the 

U.S. in over 30 years, and we have no 

indication of any plans for future 

construction. In addition, we believe 

that any future demand for new or 

replacement chlor-alkali production 

capacity would be met easily through 

the construction of new production 

facilities that do not use or emit 

mercury. Consequently, we believe it is 

appropriate to consider non-mercury 

cell facilities as similar sources and the 

prohibition of new mercury cell chloralkali production facilities achievable. 

Accordingly, we are proposing a 

complete prohibition on mercury 

emissions for new source MACT for 

mercury cell chlor-alkali production 

facilities. We are not proposing any 

initial and continuous compliance 

requirements related to this emission 

limit as we believe they are unnecessary 

since the emissions prohibition 

effectively precludes the new 

construction or reconstruction of a 

mercury cell chlor-alkali production 

facility. 

As highlighted in the previous 

discussion on the selection of standards 

for existing sources, the emission levels 

achieved by the best-controlled sources 

were selected as the proposed existing 

source MACT levels for mercury 

recovery facilities. These best levels of 

control for point sources are 23 mg/

dscm of exhaust from an oven type 

mercury thermal recovery unit vent, and 

4 mg/dscm of exhaust from a non-oven 

type mercury thermal recovery unit 

vent. For fugitive emission sources, the 

best level of control identified is the 

work practice standard represented in 

Federal Register / Vol. 67, No. 128 / Wednesday, July 3, 2002 / Proposed Rules 44689

the beyond-the-floor option selected for 

proposal for existing sources. 

In the case of mercury recovery 

facilities, we know of three plants that 

employ low emitting mercury recovery 

processes. These processes include 

chemical mercury recovery used at two 

plants and recovery in a batch 

purification still used at a third plant. 

Unlike thermal recovery units which are 

capable of treating a variety of waste 

types, the chemical recovery and the 

purification still processes have limited 

application. Both are suitable to treating 

only certain waste types, K106 wastes 

for the former and end-box residues for 

the latter. Plants using these nonthermal 

recovery processes transfer their 

remaining wastes off-site for treatment, 

which typically involves thermal 

recovery. Given this limitation, we do 

not believe that these nonthermal 

recovery processes qualify as a suitable 

basis for new source MACT. 

Consequently, for new source MACT for 

mercury recovery facilities, we are 

proposing numerical mercury emission 

limits consistent with that achieved by 

the best similar sources, 23 mg/dscm for 

oven type thermal recovery unit vent 

and 4 mg/dscm for non-oven type 

thermal recovery units. 

F. How did We Select the Testing and 

Initial Compliance Requirements? 

We selected the proposed testing and 

initial and continuous compliance 

requirements based on requirements 

specified in the NESHAP General 

Provisions (40 CFR part 63, subpart A). 

These requirements were adopted for 

mercury cell chlor-alkali plants to be 

consistent with other part 63 NESHAP. 

These requirements were chosen to 

ensure that we obtain or have access to 

sufficient information to determine 

whether an affected source is complying 

with the standards specified in the 

proposed rule. 

The proposed rule would require 

initial and periodic compliance tests for 

determining compliance with the 

emission limits for by-product hydrogen 

streams and end-box ventilation system 

vents, and the emission limits for oven 

type and non-oven type mercury 

thermal recovery unit vents. The 

proposed rule would require the use of 

published EPA methods for measuring 

total mercury. Specifically, the 

proposed rule would allow the use of 

Method 101 or 101A (of appendix A of 

40 CFR part 61) for end-box ventilation 

system vents and mercury thermal 

recovery unit vents and Method 102 for 

by-product hydrogen streams. Methods 

101 and 102 were developed in the 

1970’s specifically for use at mercury 

cell chlor-alkali plants. Although 

Method 101A was developed to measure 

mercury emissions from sewage sludge 

incinerators, it is appropriate for use for 

end-box ventilation system vents and 

mercury thermal recovery unit vents.

The NESHAP General Provisions 

specify at § 63.7(e)(3) that each test 

consist of three separate test runs. The 

proposed rule would adopt this 

requirement. Further, the proposed rule 

would require that each test run be at 

least 2 hours long. This is the duration 

specified in Method 101 and referenced 

in Methods 101A and 102. 

In the stack test data that were 

provided to us, there were numerous 

incidents where the results were 

reported as ‘‘less than’’ a certain level. 

We believe that this is primarily related 

to the sensitivity of the analytical 

instrument (that is, the absorption 

spectrophotometer) used to measure the 

amount of mercury in the collected 

sample. Method 101 states that the 

absorption spectrometer must be the 

‘‘Perkin Elmer 303, or equivalent, 

containing a hollow-cathode mercury 

lamp and the optical cell ***.’’ It is 

our understanding that this particular 

model is no longer commercially 

available, and that newer, more 

sensitive absorption spectrophotometers 

are available. We considered whether it 

was necessary to specify, either in the 

proposed rule or through a modification 

to the test method, that Perkin Elmer 

303 did not have to be used. We 

concluded that the ‘‘or equivalent’’

language contained in Method 101 

allows for the use of newer, more 

sensitive instruments and as a result, 

adding rule language or amending 

Method 101 was unnecessary. 

Even with the 2-hour minimum test 

run period and the clarification that 

newer, more sensitive absorption 

spectrophotometers are allowed to be 

used, we remain concerned that 

quantifiable results of mercury 

emissions may not be obtained during 

performance tests. As a result, the 

proposed rule includes a requirement 

that the amount of mercury collected 

during each test run be at least 2 times 

the limit of detection for the analytical 

method used. This will assure that a 

reliably quantifiable amount of mercury 

is collected for each test run. 

The emission limits for by-product 

hydrogen streams and end-box 

ventilation system vents are in the form 

of mass of mercury emissions per mass 

of chlorine produced. Therefore, criteria 

for the measurement of chlorine 

production during performance testing 

are also necessary. It is our 

understanding that instrumentation 

used to measure actual chlorine 

production, as well as the location and 

frequency of measurement, varies from 

plant to plant. Types of instruments 

used include rail car weigh scales, 

weigh cells on liquid storage tanks, and 

gas flow meters. Calibration procedures 

for these instruments are plant-specific 

and dependent on the involvement of 

third parties concerned with quantifying 

actual chlorine production for billing 

and other purposes. Moreover, at a 

given plant, an accurate value for actual 

chlorine production based on these 

measurements is generally obtained at 

the end of an operating month when 

mass balance calculations are performed 

to verify measurements. 

For a compliance test run on the order 

of several hours, we, therefore, needed 

to rely on some other reasonable 

indicator of chlorine production. All 

mercury cell chlor-alkali plants measure 

the electric current through on-line 

mercury cells, also known as the cell 

line load or cell line current load, with 

a digital monitor that provides readings 

continuously. This cell line current load 

measurement can be used in 

conjunction with a theoretical chlorine 

production rate factor to obtain the 

instantaneous chlorine production rate. 

The theoretical factor is based on a 

statement of Faraday’s Law that 96,487 

Coulombs (Faraday’s constant, where a 

Coulomb is a fundamental unit of 

electrical charge) are required to 

produce one gram equivalent weight of 

the electrochemical reaction product 

(chlorine). It is our understanding that 

chlorine production calculated in this 

manner would differ from the actual 

quantity produced at the plant by about 

3 to 7 percent due to electrical 

conversion efficiency and reaction 

efficiency determined by equipment 

characteristics and operating conditions. 

We consider this degree of variability 

acceptable. 

We, therefore, stipulate in the 

proposed rule that the cell line current 

load be continuously measured during a 

performance test run and that 

measurements be recorded at least every 

15 minutes over the duration of the test 

run. We further specify equations for 

computing the average cell line current 

load and for calculating the quantity of 

chlorine produced over the test run. 

In addition to the requirement to 

conduct performance tests to 

demonstrate compliance with the 

emission limits, owners or operators 

would be required to establish a 

mercury concentration operating limit 

for each vent as part of the initial 

compliance demonstration. Then, at 

least twice a permit term (at mid-term 

and renewal), they would conduct 

subsequent compliance demonstrations 

and at the same time reestablish 

44690 Federal Register / Vol. 67, No. 128 / Wednesday, July 3, 2002 / Proposed Rules 

operating limit values. The proposed 

rule would require that these mercury 

concentration operating limits be 

determined directly from the 

concentration monitoring data collected 

concurrent with the initial performance 

test.

For the work practice standards, 

initial compliance is demonstrated by 

documenting and certifying that the 

standards are being met or will be met 

by submitting a washdown plan and by 

certifying that the plan is being followed 

or will be followed. This approach 

assures initial compliance by requiring 

the owner or operator to submit a 

certified statement in the Notification of 

Compliance Status report. 

G. How Did We Select the Continuous 

Compliance Requirements? 

For each of the proposed emission 

limits, which consist of the limits on 

mercury emissions from hydrogen 

streams, end-box ventilation systems, 

and thermal recovery units, we 

considered the feasibility and suitability 

of continuous emission monitors (CEM) 

as the means of demonstrating 

continuous compliance. While we were 

unable to identify any mercury cell 

chlor-alkali plant currently using a 

mercury CEM on any vent, we did 

determine that there are mercury CEM 

commercially available that may be 

suitable for use at mercury cell chloralkali plants. To date, most of the 

development work on mercury CEM has 

focused on the development of monitors 

for the continuous measurement of 

mercury air emissions from either coalfired utility boilers or hazardous waste 

incinerators. Most mercury CEM are 

extractive monitors which extract a 

continuous or nearly continuous sample 

of gas, then transfer the gas to an 

instrument for spectroscopic analysis by 

way of either cold vapor atomic 

absorption or cold vapor atomic 

fluorescence. 

These cold vapor techniques have 

similar limitations. Both detect mercury 

vapor only in its elemental form. To 

measure other forms of mercury vapor 

(e.g., oxidized/inorganic/divalent 

mercury, such as mercuric chloride), the 

sampled gases must first pass through a 

converter which reduces any 

nonelemental mercury vapor present to 

the elemental form prior to analysis. 

None of the available monitors based on 

the cold vapor techniques are capable of 

measuring particulate or nonvapor 

phase mercury since the sample gas 

must be filtered to remove any 

particulate matter present prior to 

conversion and analysis. This would 

include elemental mercury condensed 

on particulate matter and any mercury 

compounds in particulate form. 

Monitors that are capable of measuring 

total vapor phase mercury range in price 

from $50,000 to $80,000. Simpler 

monitors that measure only elemental 

mercury vapor average about $10,000. 

For the proposed emission limits for 

by-product hydrogen streams and endbox ventilation system vents, which are 

expressed in grams of mercury per 

megagram of chlorine produced, we 

evaluated two options: continuous 

compliance against the proposed gram 

per megagram standards, and 

continuous compliance against plant 

and vent specific operating limits 

expressed in terms of concentration. In 

addition to monitoring mercury 

concentration, the first option would 

require continuous monitoring of 

volumetric flow rate and a continuous, 

or at least periodic, measurement of 

chlorine production. The operating 

limits for the second option would be 

set at the time that initial compliance 

with the emission limit is demonstrated. 

Since the predominant form of liquid 

mercury in mercury cells and other 

production facilities is elemental, we 

assumed that the mercury contained in 

the vent gas from either by-product 

hydrogen streams or end-box ventilation 

system vents is similarly largely in the 

elemental vapor form. Thus, the 

simpler, less expensive monitors for 

measuring elemental mercury vapor 

only should be suitable. 

We concluded that monitoring only 

elemental mercury concentration 

provides a simpler, less expensive, and 

more reliable alternative to 

demonstrating continuous compliance 

than monitoring against the gram per 

megagram standards. As a result, we are 

proposing that continuous compliance 

for by-product hydrogen streams and 

end-box ventilation system vents be 

demonstrated through the continuous 

monitoring of elemental mercury 

concentration in the vent exhaust. 

To the best of our knowledge, 

mercury contained in the exhaust gas of 

thermal recovery units, both oven and 

non-oven types, should exist as both 

vapor (elemental or nonelemental) and 

fine particulate matter. As highlighted 

above, none of the currently available 

monitors are capable of measuring 

particulate mercury. Consequently, 

continuous monitoring to demonstrate 

continuous compliance with the total 

mercury concentration limit would not 

be possible. 

Similar to the by-product hydrogen 

streams and end-box ventilation system 

vents, we also considered the feasibility 

and usefulness of monitoring vapor 

phase mercury, specifically the 

elemental form. We concluded that the 

continuous monitoring of elemental 

mercury vapor as a surrogate to the total 

mercury emission limit using the 

simpler of the available monitors 

provides an acceptable and costeffective means of tracking relative 

changes in emissions and control device 

performance. Therefore, as proposed for 

by-product hydrogen streams and endbox ventilation system vents, we are 

proposing for oven type and non-oven 

type mercury thermal recovery units 

that continuous compliance be 

demonstrated through continuous 

monitoring of elemental mercury 

concentration against an applicable 

concentration operating limit 

established as part of the initial 

compliance demonstration.

Another important aspect of 

continuous compliance is the time 

period over which continuous 

compliance is determined. One option 

would be an instantaneous period, 

where any measurement outside of the 

established range (that is, above the 

established concentration limit) would 

constitute a deviation. More commonly, 

the average of the monitoring data over 

a specified time period, for example an 

hour, is compared to the established 

limit. 

While mercury cell chlor-alkali 

production facilities are generally 

operated continuously, there are process 

fluctuations that impact emissions. 

Mercury recovery facilities are operated 

intermittently, depending on the 

amount of mercury-containing waste to 

be treated and other factors. We believe 

that an emissions averaging period is 

necessary for both situations. We 

considered a daily averaging period and 

concluded that daily averaging would 

accommodate process variations while 

precluding avoidable periods of high 

emissions. Therefore, we are proposing 

a daily averaging period for 

demonstrating continuous compliance. 

We also considered how to address 

monitoring data collected during 

startups, shutdowns, and malfunctions. 

We believe that it is important to 

continue to monitor the outlet mercury 

concentration during startups, 

shutdowns, and malfunctions to 

minimize emissions and to demonstrate 

that the plant’s startup, shutdown, and 

malfunction plan is being followed. 

However, as provided for in the 

NESHAP General Provisions (40 CFR 

part 63, subpart A), we do not believe 

that the data collected during these 

periods should be used in calculating 

the daily average values. The emission 

limits were developed based on normal 

operation, and the performance tests 

will be conducted during representative 

operating conditions. Therefore, the 

Federal Register / Vol. 67, No. 128 / Wednesday, July 3, 2002 / Proposed Rules 44691

inclusion of monitoring data collected 

during startups, shutdowns, and 

malfunctions into the daily averages 

would be inconsistent with the data 

used to develop the emission limits and, 

subsequently, the mercury 

concentration operating limits. 

While we did not identify situations 

in the mercury cell chlor-alkali industry 

where elemental mercury concentration 

is being continuously monitored, we 

believe that continuous elemental 

mercury concentration monitoring 

devices are available for use at mercury 

cell chlor-alkali plants. We recognize 

that the transfer of this monitoring 

technology to applications at mercury 

cell chlor-alkali plants will introduce 

uncertainties that can only be addressed 

through actual field demonstration. We 

are specifically requesting comment on 

the technical feasibility of using 

continuous elemental mercury 

concentration monitors for indicating 

relative changes in control system 

performance. We are also requesting 

comment on the proposed specifications 

for these devices. 

Continuous compliance with the 

proposed work practice standards for 

the fugitive emission sources would be 

demonstrated by maintaining the 

required records documenting 

conformance with the standards and by 

maintaining the required records 

showing that the washdown plan was 

followed. 

H. How Did We Select the Notification, 

Recordkeeping, and Reporting 

Requirements? 

We selected the proposed notification, 

recordkeeping, and reporting 

requirements based on requirements 

specified in the NESHAP General 

Provisions (40 CFR part 63, subpart A). 

As with the proposed initial and 

continuous compliance requirements, 

these requirements were adapted for 

mercury cell chlor-alkali plants to be 

consistent with other part 63 national 

emission standards. 

IV. Summary of Environmental, Energy, 

Cost, and Economic Impacts 

A. What Are the Air Emission Impacts? 

As discussed previously, the level of 

mercury emissions allowed by the 

Mercury NESHAP is 2,300 grams per 

day. If one assumes that all twelve 

plants in the source category emit 

mercury at this level and that each 

operates 365 days a year, total annual 

potential-to-emit baseline emissions 

would be 10,074 kg/yr (22,200 lb/yr). 

Annual potential-to-emit baseline 

emissions for fugitive emission sources 

would be 5,694 kg/yr (12,544 lb/yr), 

based on 1,300 grams per day assumed 

for each plant’s cell room ventilation 

system when the eighteen design, 

maintenance, and housekeeping 

practices referenced in the Mercury 

NESHAP are followed. Annual 

potential-to-emit baseline emissions for 

by-product hydrogen streams, end-box 

ventilation system vents, and mercury 

thermal recovery unit vents would be 

4,380 kg/yr (9,656 lb/yr), based on the 

remaining 1,000 grams per day allowed. 

We estimate that the proposed rule 

would reduce industrywide mercury 

emissions for by-product hydrogen 

streams, end-box ventilation system 

vents, and mercury thermal recovery 

unit vents from this annual potential-toemit baseline to around 245 kg/yr (545 

lb/yr), which is equivalent to about 94 

percent reduction. 

While the level of mercury emissions 

allowed by the Mercury NESHAP 

defines the potential-to-emit baseline, 

the sum of annual mercury emissions 

releases from by-product hydrogen 

streams, end-box ventilation system 

vents, and mercury thermal recovery 

vents, as estimated by mercury cell 

chlor-alkali plants, defines an annual 

actual baseline for vents of about 935 

kg/yr (2,060 lb/yr). We estimate that the 

proposed rule would reduce 

industrywide mercury emissions for 

vents from this annual actual baseline to 

around 245 kg/yr (545 lb/yr), which is 

equivalent to about 74 percent 

reduction.

We estimate that secondary air 

pollution emissions would result from 

the production of electricity required to 

operate new control devices and new 

monitoring equipment assumed for 

plant vents. Assuming electricity 

production as based entirely on coal 

combustion for a worst-case scenario, 

we estimated plant-specific impacts for 

carbon dioxide, sulfur dioxide, nitrogen 

oxides, particulate matter, and carbon 

monoxide emissions. The total 

estimated secondary air impacts of the 

proposed requirements for point sources 

at the twelve mercury cell chlor-alkali 

plants is around 554 Mg/yr (611 tpy) for 

all pollutants combined, with carbon 

dioxide emissions comprising 99 

percent of the estimate. 

We are unable to quantify the primary 

air emission impacts associated with the 

proposed work practice standards, so no 

mercury emission reduction is assumed 

for fugitive emission sources. However, 

we believe strongly that the new and 

more explicit requirements contained in 

the proposed standards will in fact 

result in mercury emission reductions 

beyond baseline levels. Relative to 

secondary impacts, we expect that 

secondary air pollution emissions, 

principally carbon dioxide, would result 

from the production of electricity 

required to operate new monitoring 

equipment assumed for plant cell 

rooms. We estimate the secondary air 

impacts of the proposed rule for fugitive 

sources to be 17 Mg/yr (19 tpy). 

B. What Are the Non-Air Health, 

Environmental, and Energy Impacts? 

We do not expect that there will be 

any significant adverse non-air health 

impacts associated with the proposed 

standards for mercury-cell chlor-alkali 

plants. 

We estimate that an increase in the 

amount of mercury-containing waters 

would result from the heightened use of 

packed tower scrubbing assumed for 

several plant vents. The total estimated 

water pollution impact of the proposed 

rule for point sources is about 1.8 

million liters (466 thousand gallons) of 

additional wastewater per year. We 

estimate that an increase in the amount 

of mercury-containing solid wastes 

would result with the heightened use of 

carbon adsorption assumed for several 

plant vents. The total estimated solid 

waste impact of the proposed rule for 

point sources is about 34 Mg/yr (38 tpy) 

of additional mercury-containing spent 

carbon. 

We are unable to quantify non-air 

environmental impacts associated with 

the proposed work practice standards, 

so no wastewater and solid waste 

impacts are assumed for fugitive 

emission sources. 

We estimate that the proposed 

requirements for point sources would 

result in increased energy consumption, 

specifically additional fan power in 

conveying gas streams through new 

carbon adsorbers and new packed 

scrubbers assumed for certain plant 

vents and additional power consumed 

by new vent monitoring equipment. The 

total estimated energy impacts of the 

proposed requirements for point sources 

is about 1,724 thousand kW-hr/yr. 

We estimate that the proposed 

requirements for fugitive sources would 

result in increased energy consumption 

required to operate new monitoring 

equipment assumed for plant cell 

rooms. The total estimated energy 

impacts of the proposed requirements 

for fugitive sources is about 53 thousand 

kW-hr/yr. 

C. What Are the Cost and Economic 

Impacts? 

For projecting cost impacts of the 

proposed rule on the mercury cell chloralkali industry, we estimate that all 

twelve plants would incur costs to meet 

the proposed work practice standards 

and the proposed monitoring, 

44692 Federal Register / Vol. 67, No. 128 / Wednesday, July 3, 2002 / Proposed Rules 

recordkeeping, and reporting 

requirements. We estimate that ten 

plants would incur costs to meet the 

proposed emission limits for by-product 

hydrogen streams and end-box 

ventilation system vents, and three 

plants would incur costs to meet the 

proposed emission limits for mercury 

thermal recovery units. The total 

estimated capital cost of the proposed 

rule for the twelve mercury cell chloralkali plants is around $2.5 million, and 

the total estimated annual cost is about 

$2.2 million per year. Plant-specific 

annual costs in our estimate range from 

about $91,000 for the least-impacted 

plant to about $375,000 for the worstimpacted plant.

The purpose of the economic impact 

analysis is to estimate the market 

response of chlor-alkali production 

facilities to the proposed standards and 

to determine the economic effects that 

may result due to the proposed 

NESHAP. Chlor-alkali production 

jointly creates both chlorine and caustic, 

usually sodium hydroxide, in fixed 

proportions. Being joint commodities, 

the economic analysis considers the 

impacts of the proposed NESHAP on 

both the chlorine and sodium hydroxide 

markets. 

The chlorine production source 

category contains 43 facilities, but only 

twelve facilities using mercury cells are 

directly affected by the proposed 

standards. These twelve facilities are 

located at twelve plants that are owned 

by eight companies. Although one of 

these twelve plants permanently closed 

due to reasons unrelated to this 

rulemaking, the following impacts are 

based on the twelve plants in operation 

at the time the analysis was conducted. 

Chlor-alkali production in mercury 

cells leads to potential mercury 

emissions from hydrogen streams, endbox ventilation system vents, mercury 

thermal recovery units, and fugitive 

emission sources. The compliance costs 

for the proposed standards, therefore, 

relate to the purchase, installation, 

operation, and maintenance of pollution 

control equipment at the point sources, 

as well as the labor costs and overheads 

associated with observing work 

practices addressing fugitive emissions. 

The estimated total annual costs for the 

proposed NESHAP are $1.8 million. 

This cost estimate represents about 0.38 

percent of the 1997 chlorine sales 

revenue for the twelve mercury cell 

chlor-alkali production facilities. 

Furthermore, the total annual costs 

represent only 0.01 percent of the 

revenues of owning the directly affected 

mercury cell chlor-alkali plants. 

The economic analysis predicts 

minimal changes in industry outputs 

and the market prices of chlorine and 

sodium hydroxide as a result of the 

estimated control costs. The new market 

equilibrium quantities of chlorine and 

sodium hydroxide decrease by less than 

0.1 percent. Equilibrium prices of 

chlorine and sodium hydroxide both 

rise by less than 0.1 percent due to the 

proposed standards. Based on these 

estimates, we conclude that the 

proposed standards are not likely to 

have a significant economic impact on 

the chlorine production industry as a 

whole or on secondary markets such as 

the labor market and foreign trade. 

We perform an economic analysis to 

determine facility- and companyspecific impacts. These economic 

impacts are measured by calculating the 

ratio of the estimated annualized 

compliance costs of emissions control 

for each entity to its revenues (i.e., costto-sales ratio). After the cost-to-sales 

ratio is calculated for each entity, it is 

then multiplied by 100 to convert the 

ratio into percentages. Actual revenues 

at the facility level are not available, 

therefore, estimated facility revenues 

received from the sale of chlorine are 

used. Some of these facilities also 

produce caustic as potassium 

hydroxide, but the revenues from the 

sale of this product are not estimated. 

The twelve mercury cell chlor-alkali 

plants have positive cost-to-sales ratios. 

The ratio of costs to estimated chlorine 

sales revenue for these facilities range 

from a low of 0.16 percent to a high of 

1.00 percent. The average cost-to-sales 

ratio for the twelve mercury process 

chlorine production facilities is 0.46 

percent. More detailed economic 

analysis predicted minimal changes in 

chlorine production at each facility. 

Thus, overall, the economic impact of 

the proposed standards is minimal for 

the facilities producing chlorine. 

The share of compliance costs to 

company sales are calculated to 

determine company level impacts. Since 

eight companies own the twelve 

affected facilities, all eight firms face 

positive compliance costs from the 

proposed NESHAP. The ratio of costs to 

estimated revenues range from a low of 

less than 0.01 percent to a high of 0.22 

percent, and the average ratio of costs to 

company revenues is 0.06 percent. 

Again, more detailed economic analysis 

at the company level predicts little 

change in company output or revenues. 

So, at the company level, the proposed 

standards are not anticipated to have a 

significant economic impact on 

companies that own and operate the 

chlorine production facilities.

No facility or company is expected to 

close as a result of the proposed 

standards, and the economic impacts to 

consumers are anticipated to be 

minimal. The generally small scale of 

the impacts suggests that there will also 

be no significant impacts on markets for 

the products made using chlorine or 

sodium hydroxide. For more 

information, consult the economic 

impact analysis report entitled 

‘‘Economic Impact Analysis for the 

Proposed Mercury Cell Chlor-Alkali 

Production NESHAP,’’ which is 

available in the docket to this 

rulemaking. 

V. Solicitation of Comments and Public 

Participation 

We seek full public participation in 

arriving at final decisions and encourage 

comments on all aspects of the proposed 

standards from all interested parties. 

You need to submit appropriate 

supporting data and analyses with your 

comments to allow us to make the best 

use of them. Be sure to direct your 

comments to the Air and Radiation 

Docket and Information Center, Docket 

No. A–2000–32 (see ADDRESSES). 

VI. Administrative Requirements 

A. Executive Order 12866, Regulatory 

Planning and Review 

Under Executive Order 12866 (58 FR 

51735, October 4, 1993), the EPA must 

determine whether the regulatory action 

is ‘‘significant’’ and, therefore, subject to 

review by the Office of Management and 

Budget (OMB) and the requirements of 

the Executive Order. The Executive 

Order defines ‘‘significant regulatory 

action’’ as one that OMB determines is 

likely to result in a rule that may: 

(1) Have an annual effect on the 

economy of $100 million or more or 

adversely affect in a material way the 

economy, a sector of the economy, 

productivity, competition, jobs, the 

environment, public health or safety, or 

State, local, or Tribal governments or 

communities; 

(2) Create a serious inconsistency or 

otherwise interfere with an action taken 

or planned by another agency; 

(3) Materially alter the budgetary 

impact of entitlements, grants, user fees, 

or loan programs or the rights and 

obligations of recipients thereof; or 

(4) Raise novel legal or policy issues 

arising out of legal mandates, the 

President’s priorities, or the principles 

set forth in this Executive Order. 

Pursuant to the terms of Executive 

Order 12866, it has been determined 

that the proposed rule is not a 

‘‘significant regulatory action’’ because 

none of the listed criteria apply to this 

action. Consequently, this action was 

not submitted to OMB for review under 

Executive Order 12866. 

Federal Register / Vol. 67, No. 128 / Wednesday, July 3, 2002 / Proposed Rules 44693

B. Executive Order 13132 (Federalism)

Executive Order 13132, entitled 

‘‘Federalism’’ (64 FR 43255, August 10, 

1999), requires the 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 rules 

that have ‘‘substantial direct effects on 

the States, on the relationship between 

the national government and the States, 

or on the distribution of power and 

responsibilities among the various 

levels of government.’’ Under section 6 

of Executive Order 13132, the EPA may 

not issue a rule that has federalism 

implications, that imposes substantial 

direct compliance costs, and that is not 

required by statute, unless the Federal 

government provides the funds 

necessary to pay the direct compliance 

costs incurred by State and local 

governments, or the EPA consults with 

State and local officials early in the 

process of developing the rule. The EPA 

also may not issue a rule that has 

federalism implications and that 

preempts State law unless the Agency 

consults with State and local officials 

early in the process of developing the 

rule. 

If the EPA complies by consulting, 

Executive Order 13132 requires the EPA 

to provide to OMB, in a separately 

identified section of the preamble to the 

rule, a federalism summary impact 

statement (FSIS). The FSIS must include 

a description of the extent of the EPA’s 

prior consultation with State and local 

officials, a summary of the nature of 

their concerns and the Agency’s 

position supporting the need to issue 

the rule, and a statement of the extent 

to which the concerns of State and local 

officials have been met. Also, when the 

EPA transmits a draft final rule with 

federalism implications to OMB for 

review pursuant to Executive Order 

12866, the EPA must include a 

certification from the Agency’s 

Federalism Official stating that the EPA 

has met the requirements of Executive 

Order 13132 in a meaningful and timely 

manner. 

The proposed rule will not have 

substantial direct effects on the States, 

on the relationship between the national 

government and the States, or on the 

distribution of power and 

responsibilities among the various 

levels of government, as specified in 

Executive Order 13132. The proposed 

rule is mandated by statute and does not 

impose requirements on States; 

however, States will be required to 

implement the rule by incorporating the 

rule into permits and enforcing the rule 

upon delegation. States will collect 

permit fees that will be used to offset 

the resource burden of implementing 

the rule. Thus, the requirements of 

section 6 of the Executive Order do not 

apply to the proposed rule. Although 

section 6 of Executive Order 13132 does 

not apply to the proposed rule, the EPA 

did consult with State and local officials 

in developing the proposed rule. 

C. Executive Order 13175, Consultation 

and Coordination with Indian Tribal 

Governments 

Executive Order 13175, entitled 

‘‘Consultation and Coordination with 

Indian Tribal Governments’’ (65 FR 

67249, November 6, 2000), requires the 

EPA to develop an accountable process 

to ensure ‘‘meaningful and timely input 

by tribal officials in the development of 

regulatory policies that have tribal 

implications.’’ ‘‘Policies that have tribal 

implications’’ is defined in the 

Executive Order to include regulations 

that have ‘‘substantial direct effects on 

one or more Indian tribes, on the 

relationship between the Federal 

government and the Indian tribes, or on 

the distribution of power and 

responsibilities between the Federal 

government and Indian tribes.’’

The proposed rule does not have 

tribal implications. It will not have 

substantial direct effects on tribal 

governments, on the relationship 

between the Federal government and 

Indian tribes, or on the distribution of 

power and responsibilities between the 

Federal government and Indian tribes, 

as specified in Executive Order 13175. 

Thus, Executive Order 13175 does not 

apply to the proposed rule.

In the spirit of Executive Order 13175 

and consistent with EPA policy to 

promote communications between EPA 

and tribal governments, EPA 

specifically solicits additional comment 

on the proposed rule from tribal 

officials. 

D. Executive Order 13045, Protection of 

Children From Environmental Health 

Risks and Safety Risks 

The Executive Order 13045 applies to 

any rule (1) that OMB determines is 

‘‘economically significant,’’ as defined 

under Executive Order 12866, and (2) 

the EPA determines that the 

environmental health or safety risk 

addressed by the rule has a 

disproportionate effect on children. If 

the regulatory action meets both criteria, 

the EPA must evaluate the 

environmental, health, or safety aspects 

relevant to children and explain why 

the rule is preferable to other potentially 

effective and reasonably feasible 

alternatives considered by the EPA. 

As with most rulemakings developed 

under section 112(d) of the CAA, 

today’s proposal is based on MACT. 

Risks to public health and impacts on 

the environment are not typically 

considered in the development of 

emissions standards under section 

112(d). Rather, these risks and impacts 

are considered later (within 8 years after 

promulgation of the MACT rule) under 

the residual risk program as required by 

section 112(f) of the CAA. While we do 

not believe the proposed rule to be 

‘‘economically significant,’’ as defined 

under Executive Order 12866, we do 

believe that it addresses environmental 

health or safety risks that may have a 

disproportionate effect on children. 

Mercury has been identified as a 

priority pollutant under EPA’s National 

Agenda to Protect Children’s Health 

from Environmental Threats and by the 

Federal Children’s Health Protection 

Advisory Committee (CHPAC). The 

CHPAC was formed to advise, consult 

with, and make recommendations to the 

EPA on issues associated with the 

development of regulations to address 

the prevention of adverse health effects 

to children. One of the CHPAC’s 

primary missions was to identify five 

existing EPA regulations, which if 

reevaluated, could lead to better 

protection for children. The CHPAC 

recommended the Mercury NESHAP for 

chlor-alkali plants as one of the 

regulations to be reevaluated 

considering impacts on children. We 

adopted the CHPAC recommendation. 

Therefore, we have considered the 

impacts on children in the development 

of the proposed rule. A qualitative 

assessment of the potential impacts on 

children’s health due to mercury 

emissions from chlor-alkali plants is 

presented here. 

1. What Is Mercury and How Is It 

Transported in the Environment? 

Mercury is a naturally occurring 

element found in air, water and soil. 

Mercury is found in various inorganic 

and organic forms in the environment. 

The three primary forms of interest for 

this assessment are: elemental mercury, 

inorganic or divalent mercury, and 

methylmercury. Based on available 

information, it appears that most of the 

mercury emitted from chlor-alkali 

plants is in the elemental form, and a 

small percentage is in the divalent form. 

The air transport and deposition 

patterns of mercury emissions depend 

on various factors including the 

chemical form of mercury emitted, stack 

height, characteristics of the area 

surrounding the site, topography, and 

44694 Federal Register / Vol. 67, No. 128 / Wednesday, July 3, 2002 / Proposed Rules 

meteorology. As it moves through 

environmental media (e.g., air, 

sediments, water), mercury undergoes 

complex transformations. 

Mercury is highly toxic, persistent, 

and bioaccumulates in the food chain. 

The mercury emitted to the air from 

various types of sources (usually in 

elemental or divalent forms) transports 

through the atmosphere and eventually 

deposits onto land or water bodies. The 

deposition can occur locally near the 

source or at long distances (e.g., 

hundreds or thousands of miles away). 

Once deposited, the chemical form of 

mercury can change (through a 

methylation process) into 

methylmercury (MeHg), which 

biomagnifies in the aquatic food chain. 

As reported in the 1997 EPA Mercury 

Study, nearly all of the mercury that 

accumulates in fish is MeHg. Generally, 

fish consumption dominates the 

pathway for human and wildlife 

exposure to mercury. As of July 2000, 40 

States have issued fish advisories for 

mercury. Thirteen of these States have 

issued advisories for all water bodies in 

their State, and the other 27 States have 

issued advisories for over 1,900 specific 

water bodies. 

2. What Are the Health Effects of the 

Various Mercury Compounds? 

The health effects of the various 

mercury compounds were discussed 

earlier. Methylmercury is discussed 

further in this section because it is the 

primary form for which the general U.S. 

population is exposed. 

Neurotoxicity is the health effect of 

greatest concern with MeHg exposure. 

The developing fetus is considered most 

sensitive to the effects from MeHg. 

Therefore, women of child-bearing age 

are the population of greatest concern. 

Some offspring born of women exposed 

to relatively high doses of MeHg during 

pregnancy exhibited a variety of 

developmental neurological 

abnormalities, including delayed onset 

of walking and talking, cerebral palsy, 

and reduced neurological test scores. 

Far lower in utero exposures have 

resulted in delays and deficits in 

learning abilities. It is also possible that 

children exposed after birth are also 

potentially more sensitive to the toxic 

effects of MeHg than adults because 

their nervous systems are still 

developing.

Extrapolating from high-dose 

exposure incidents, we derived a 

reference dose (RfD) for MeHg of 0.1 

microgram per kilogram body weight 

per day (0.1 ug/kg/day) based on 

developmental neurological effects 

observed in children born to mothers 

who were exposed to MeHg during 

pregnancy. The RfD is an estimated 

daily ingestion level anticipated to be 

without adverse effect to persons, 

including sensitive subpopulations, 

over a lifetime. At the RfD or below, 

exposures are expected to be safe. The 

risks following exposures above the RfD 

are uncertain, but the potential for 

adverse health effects increases as 

exposures to MeHg increase. The 

National Academy of Sciences (NAS), in 

its July 2000 report ‘‘Toxicological 

Effects of Methylmercury’’ (NAS, 2000), 

affirmed our assessment of MeHg 

toxicity and the level of our RfD. 

3. What Are the Human Exposures to 

MeHg and the Potential Health Impacts? 

The results of dietary surveys indicate 

that most of the U.S. population 

consumes fish and is exposed to some 

MeHg as a result. The typical fish 

consumer (who eats moderate amounts 

of fish from restaurants and grocery 

stores) in the U.S. is not likely to be at 

risk of consuming harmful levels of 

MeHg; however, people who eat more 

fish than is typical or eat fish that are 

more contaminated than typical fish 

may be at risk. Furthermore, certain 

groups, such as pregnant women and 

their fetuses, young children, and 

subsistence fish-eating populations may 

be at particular risk. 

Based on an exposure assessment 

presented in the 1997 EPA Mercury 

Study, we estimate that about 7 percent 

of women of childbearing age (i.e., 

between the ages of 15 and 44 years) in 

the U.S. are exposed to MeHg at levels 

exceeding the RfD, and about 1 percent 

of women have MeHg exposures 3 to 4 

times this level. Moreover, the NAS 

estimated in their recent report that over 

60,000 children born each year in the 

U.S. are at risk for adverse neurological 

effects due to in utero exposure to MeHg 

(NAS, 2000). These exposure estimates 

are also supported by a recent study by 

the U.S. Center’s for Disease Control and 

Prevention (CDC) on mercury levels in 

women of childbearing age as measured 

in hair and blood. The results of that 

study (which were published in the 

CDC’s Morbidity and Mortality Weekly 

Report on March 2, 2001) show that 

about 10 percent of women of 

childbearing age in the U.S. are exposed 

to mercury at levels above the EPA’s 

RfD. 

Methylmercury exposure rates on a 

per body weight basis among children 

are predicted to be higher than for 

adults. The EPA estimates that about 25 

percent of children are exposed to MeHg 

through consumption of fish at levels 

exceeding the RfD, and 5 percent of 

children have MeHg exposures 2 to 3 

times this level (EPA, 1997).

Most of the mercury currently 

entering U.S. water bodies and 

contaminating fish is the result of air 

emissions which, following atmospheric 

transport, deposit onto watersheds or 

directly to water bodies. We have 

concluded that there is a plausible link 

between emissions of mercury from 

anthropogenic sources (including chloralkali plants) and MeHg in fish. Waste 

water discharges also contribute to 

environmental loadings, but to a much 

lesser degree than air emissions. Based 

on modeling conducted for the 1997 

EPA Mercury Study, we estimate that 

roughly 60 percent of the total mercury 

deposited in the U.S. comes from U.S. 

anthropogenic air emission sources; this 

percentage is estimated to be even 

higher in certain regions (e.g., Northeast 

U.S.). The remainder of the deposited 

mercury comes from natural emission 

sources, re-emissions of historic global 

anthropogenic mercury releases, and 

from current anthropogenic sources 

outside the U.S. 

We predict that increased mercury 

deposition will lead to increased levels 

of MeHg in fish, and that increased 

levels in fish will lead to toxicity in 

fish-eating birds and mammals, 

including humans. The NAS, in its July 

2000 report, stated that ‘‘because of the 

beneficial effects of fish consumption, 

the long-term goal needs to be a 

reduction in the concentrations of 

methylmercury in fish.’’ We agree with 

this goal and believe that reducing 

emissions of mercury from various 

anthropogenic sources is an important 

step toward achieving this goal. 

4. What Is the Effect of Mercury 

Emissions From Chlor-Alkali Plants? 

The majority of the mercury emitted 

from chlor-alkali plants is in the 

elemental form, with a much smaller 

percent in the divalent form. As stated 

above, fish consumption generally 

dominates the pathway for human and 

wildlife exposure to mercury. However, 

for people living close to chlor-alkali 

plants, other exposure pathways may be 

significant. Appreciable exposures to 

elemental mercury and divalent 

mercury may occur through inhalation. 

Likewise, exposures to divalent mercury 

and MeHg may occur through ingestion 

of contaminated soils or plants. Based 

on modeling conducted for the 1997 

EPA Mercury Study, we estimate that 

mercury levels in multiple 

environmental media (air, soil, water, 

plants, and fish) near a typical chloralkali plant could be elevated above 

background levels. We also estimate that 

exposures for people living near these 

facilities could be higher than for people 

living further away. The extent of 

Federal Register / Vol. 67, No. 128 / Wednesday, July 3, 2002 / Proposed Rules 44695

exposures for people living near these 

plants will depend on various factors, 

including local terrain and meteorology, 

personal life style, activity patterns, and 

consumption patterns.

We admit there are uncertainties 

regarding the extent of the risks due to 

mercury emissions from specific 

anthropogenic cources. For example, 

there is no quantification of how much 

of the MeHg in fish consumed by the 

U.S. population is due to emissions 

from chlor-alkali plants relative to other 

mercury sources e.g., natural and other 

anthropogenic sourcesl. Nonetheless, 

chlor-alkali plants re significant sources 

of mercury emissions which contribute 

to the environmental loadings and to the 

exposures for humans. 

5. What Are the Effects of Aggregate 

Exposures? 

People living lcose to chlor-alkali 

plants could be exposed to elemental or 

divalent at elevated levels through 

inhalation f contaminated air and 

exposed to some divalent mercury and 

MeHg through ingestion of home grown 

plants. If these same people consumed 

fish from local ponds, they would be 

exposed to additional quantities of 

MeHg. These exposure pathways could 

be additional to those exposures more 

commonly experienced in the general 

U.S. populations such as through the 

consumption of various commercial fish 

(e.g., tuna, pollack, swordfish) and from 

dental fillings containing mercury 

amalgams. These exposures are also, 

because of mercury’s half-life in the 

human body, additional to some portion 

of a person’s previous mercury 

exposures. For people living close to 

chlor-alkali plants, this combination f 

sources may lead to elevated mercury 

exposures and body burdens. The 

degree or extent to which this occurs 

will largely depend on lifestyles, 

consumption patterns and other 

characteristics of this population. 

6. What are the Exposures and Risks For 

Children? 

Exposures for children could be 

greater than exposures for adults 

because children consume more food 

and breathe more air per body weight 

than adults. Children are also 

potentially more sensitive to the toxic 

effects of mercury than adults because 

their nervous systems are still 

developing. In addition, exposures to 

MdHg for women who are pregnant, or 

who may become pregnant, are of 

particular concern because of potential 

effects on the developing fetus. 

7. How Do Chlor-Alkali Plant Emissions 

Contribute to Global Mercury levels? 

Mercury is a globa pollutant. 

Emissions, expecially those in the 

elemental form, can transport very long 

distances and become part of the global 

pool. In addition to their potential 

contributions to mercury exposures 

locally, chlor-alkali plants are one of the 

many sources contributing to the global 

pool and to overall mercury levels in the 

environment. 

8. How Did the EPA Consider Impacts 

on Children’s Health in the 

Development of Today’s Proposed Rule?

Partly due to our concerns for 

children’s health protection, we have 

strived to develop the proposed rule 

such that it will result in the greatest 

emissions reductions that are, consistent 

with section 112(d) of the CAA, 

currently technically and economically 

feasible. Today’s proposed rule is based 

on the best available control 

technologies and stringent management 

practices. The emissions reductions 

achieved through the proposed rule will 

help reduce the mercury exposures to 

humans, including children. 

E. Unfunded Mandates Reform Act of 

1995 

Title II of the Unfunded Mandates 

Reform Act of 1995 (UMRA), Public 

Law 104–4, establishes requirements for 

Federal agencies to assess the effects of 

their regulatory actions on State, local, 

and tribal governments and the private 

sector. Under section 202 of the UMRA, 

the EPA generally must prepare a 

written statement, including a costbenefit analysis, for proposed and final 

rules with ‘‘Federal mandates’’ that may 

result in expenditures by State, local, 

and Tribal governments, in aggregate, or 

by the private sector, of $100 million or 

more in any 1 year. Before promulgating 

an EPA rule for which a written 

statement is needed, section 205 of the 

UMRA generally requires the EPA to 

identify and consider a reasonable 

number of regulatory alternatives and 

adopt the least costly, most costeffective, or least burdensome 

alternative that achieves the objectives 

of the rule. The provisions of section 

205 do not apply when they are 

inconsistent with applicable law. 

Moreover, section 205 allows the EPA to 

adopt an alternative other than the least 

costly, most cost-effective, or least 

burdensome alternative if the 

Administrator publishes with the final 

rule an explanation as to why that 

alternative was not adopted. Before the 

EPA establishes any regulatory 

requirements that may significantly or 

uniquely affect small governments, 

including Tribal governments, it must 

have developed under section 203 of the 

UMRA, a small government agency 

plan. The plan must provide for 

notifying potentially affected small 

governments, enabling officials of 

affected small governments to have 

meaningful and timely input in the 

development of EPA regulatory 

proposals with significant Federal 

intergovernmental mandates, and 

informing, educating, and advising 

small governments on compliance with 

the regulatory requirements. 

The EPA has determined that the 

proposed rule does not contain a 

Federal mandate that may result in 

expenditures of $100 million or more 

for State, local, and Tribal governments, 

in the aggregate, or the private sector in 

any 1 year. The maximum total annual 

cost of the proposed rule for any year 

has been estimated to be less than about 

$2.5 million. Thus, today’s proposed 

rule is not subject to the requirements 

of sections 202 and 205 of the UMRA. 

In addition, the EPA has determined 

that the proposed rule contains no 

regulatory requirements that might 

significantly or uniquely affect small 

governments because it contains no 

requirements that apply to such 

governments or impose obligations 

upon them. Therefore, today’s proposed 

rule is not subject to the requirements 

of section 203 of the UMRA. 

Because the proposed rule does not 

include a Federal mandate and is 

estimated to result in expenditures less 

than $100 million in any 1 year by State, 

local, and Tribal governments, the EPA 

has not prepared a budgetary impact 

statement or specifically addressed the 

selection of the least costly, most costeffective, or least burdensome 

alternative. In addition, because small 

governments will not be significantly or 

uniquely affected by the proposed rule, 

the EPA is not required to develop a 

plan with regard to small governments. 

Therefore, the requirements of the 

UMRA do not apply to this action. 

F. Regulatory Flexibility Act (RFA), as 

Amended by the Small Business 

Regulatory Enforcement Fairness Act of 

1996 (SBREFA)

The RFA generally requires that an 

agency conduct 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 will not have a 

significant economic impact on a 

substantial number of small entities. 

Small entities include small businesses, 

44696 Federal Register / Vol. 67, No. 128 / Wednesday, July 3, 2002 / Proposed Rules 

small organizations, and small 

governmental jurisdictions. 

For purposes of assessing the impacts 

of today’s proposed rule on small 

entities, small entity is defined as: (1) A 

small business with less than 1,000 

employees, (according to the Small 

Business Administration definition of a 

small business in SIC 2812); (2) a small 

governmental jurisdiction that is a 

government of a city, county, town, 

school district, or special district with a 

population of less than 50,000; or (3) a 

small organization that is any not-forprofit enterprise which is independently 

owned and operated and is not 

dominant in its field. 

After considering the economic 

impact of today’s proposed rule on 

small entities, I certify that this action 

will not have a significant impact on a 

substantial number of small entities. In 

accordance with the RFA, we conducted 

an assessment of the proposed standards 

on small businesses within the chlorine 

manufacturing industry. Based on 

definition of a small entity explained 

above, we identified three of the eight 

companies that own mercury cell chloralkali plants as small. Although small 

businesses represent 30 percent of the 

companies within the source category, 

they are expected to incur only 18 

percent of the total industry annual 

compliance costs. There are no 

companies with compliance costs equal 

to or greater than 1 percent of their 

sales. No firms are expected to close 

rather than incur the costs of 

compliance with the proposed rule. 

Furthermore, firms are not projected to 

shut down their facilities due to the 

proposed rule. 

Although the proposed rule will not 

have a significant economic impact on 

a substantial number of small entities, 

we have nonetheless worked 

aggressively to minimize the impact of 

the proposed rule on small entities, 

consistent with our obligation under the 

CAA. 

In summary, this analysis supports 

today’s certification under the RFA 

because no firms experience a 

significant impact due to the proposed 

rule. For more information, consult the 

docket for the proposed rule. 

G. Paperwork Reduction Act 

The information collection 

requirements in this proposed rule will 

be submitted for approval to OMB under 

the Paperwork Reduction Act, 44 U.S.C. 

3501 et seq. An information collection 

request (ICR) document has been 

prepared by the EPA for mercury cell 

chlor-alkali plants (ICR No. 2046.01), 

and a copy may be obtained from Sandy 

Farmer by mail at the Office of 

Environmental Information, Collection 

Strategies Division (2822), U.S. EPA, 

1200 Pennsylvania Avenue, NW., 

Washington, DC 20460, by email at 

farmer.sandy@epa.gov, or by calling 

(202) 260–2740. A copy may also be 

downloaded off the internet at http://

www.epa.gov/icr. The information 

requirements are not effective until 

OMB approves them. 

The information requirements are 

based on notification, recordkeeping, 

and reporting requirements in the 

NESHAP General Provisions (40 CFR 

part 63, subpart A), which are 

mandatory for all operators subject to 

national emission standards. These 

recordkeeping and reporting 

requirements are specifically authorized 

by section 114 of the CAA (42 U.S.C. 

7414). All information submitted to the 

EPA pursuant to the recordkeeping and 

reporting requirements for which a 

claim of confidentiality is made is 

safeguarded according to Agency 

policies set forth in 40 CFR part 2, 

subpart B. 

The proposed rule contains 

monitoring, inspection, recordkeeping, 

and reporting requirements. The 

monitoring requirements are associated 

with the use of control devices to 

observe operating limits for by-product 

hydrogen streams, end-box ventilation 

system vents, and mercury thermal 

recovery unit vents. The inspection 

requirements are associated with the 

observation of work practice standards 

for cell rooms, hydrogen systems, 

caustic systems, and the storage of 

mercury-containing wastes. The 

recordkeeping and reporting 

requirements are the means of 

complying with emission limitations 

and work practice standards in the 

proposed rule.

The respondent universe consists of 

twelve existing mercury cell chlor-alkali 

plants in the U.S. which would need to 

comply with requirements within 2 

years of the effective date of the subpart. 

The annual respondent monitoring, 

inspection, recordkeeping, and 

reporting burden for this collection of 

information (averaged over the first 3 

years after the effective date of the 

subpart) is estimated to total about 

14,000 labor hours at a total annual cost 

of about $630,000. This estimate 

includes rule review and planning; 

initial notification (one-time) to the 

EPA; one-time preparation of a startup, 

shutdown, and malfunction plan with 

semiannual reports if procedures in the 

plan were followed or immediate 

reporting if they were not followed; onetime preparation of a site-specific 

monitoring plan addressing 

performance and equipment 

specifications as well as procedures for 

performance evaluation, ongoing 

operation and maintenance, ongoing 

data quality assurance, and ongoing 

recordkeeping and reporting for 

continuous mercury vapor monitors for 

vents; acquisition and installation of 

vent monitors; performance testing for 

each vent (one time in the 3 year 

period), including notification of intent 

to conduct testing and establishment of 

vent mercury concentration operating 

limits; reporting of test results, 

including one-time preparation of 

notification of compliance status for 

vents; one-time preparation of a 

washdown plan; one-time preparation 

of notification of compliance status for 

work practice standards; continuous 

monitoring of vent outlet elemental 

mercury concentration and recording of 

data; recording of information related to 

the washdown plan; inspections and 

keeping records related to equipment 

problems, deficiencies in floors, pillars, 

and beams, caustic leaks, liquid 

mercury spills and accumulations, 

liquid mercury leaks, and hydrogen/

mercury vapor leaks; keeping records 

related to liquid mercury collection; 

keeping records related to storage of 

mercury-containing wastes; and 

preparation of semiannual compliance 

reports. 

Burden means the total time, effort, or 

financial resources expended by persons 

to generate, maintain, retain, or disclose 

or provide information to or for a 

Federal agency. This includes the time 

needed to review instructions; develop, 

acquire, install, and utilize technology 

and systems for the purposes of 

collecting, validating, and verifying 

information, processing and 

maintaining information, and disclosing 

and providing information; adjust the 

existing ways to comply with any 

previously applicable instructions and 

requirements; train personnel to be able 

to respond to a collection of 

information; search data sources; 

complete and review the collection of 

information; and transmit or otherwise 

disclose the information. 

An Agency may not conduct or 

sponsor, and a person is not required to 

respond to, a collection of information 

unless it displays a currently valid OMB 

control number. The OMB control 

numbers for our rules are listed in 40 

CFR part 9 and 48 CFR chapter 15. 

Comments are requested on EPA’s 

need for this information, the accuracy 

of the burden estimates, and any 

suggested methods for minimizing 

respondent burden, including through 

the use of automated collection 

techniques. Send comments on the ICR 

to the Director, Collection Strategies 

Federal Register / Vol. 67, No. 128 / Wednesday, July 3, 2002 / Proposed Rules 44697

Division (2822), U.S. EPA (2136), 1200 

Pennsylvania Avenue, NW, Washington, 

DC 20460; and to the Office of 

Information and Regulatory Affairs, 

Office of Management and Budget, 725 

17th Street, NW, Washington, DC 20503, 

marked ‘‘Attention: Desk Office for 

EPA.’’ Include the ICR number in any 

correspondence. Because OMB is 

required to make a decision concerning 

the ICR between 30 and 60 days after 

July 3, 2002, a comment to OMB is best 

assured of having its full effect if OMB 

receives it by August 2, 2002. The final 

rule will respond to any OMB or public 

comments on the information collection 

requirements contained in the proposed 

rule. 

H. National Technology Transfer and 

Advancement Act 

Section 12(d) of the National 

Technology Transfer and Advancement 

Act (NTTAA) of 1995 (Public Law No. 

104–113; 15 U.S.C. 272 note) directs the 

EPA to use voluntary consensus 

standards in their regulatory and 

procurement activities unless to do so 

would be inconsistent with applicable 

law or otherwise impractical. Voluntary 

consensus standards are technical 

standards (e.g., materials specifications, 

test methods, sampling procedures, 

business practices) developed or 

adopted by one or more voluntary 

consensus bodies. The NTTAA directs 

the EPA to provide Congress, through 

annual reports to OMB, with 

explanations when an agency does not 

use available and applicable voluntary 

consensus standards. 

The proposed rule involve technical 

standards. The EPA proposes in the 

proposed rule to use EPA Methods 1, 

1A, 2, 2A, 2C, 2D, 3, 3A, 3B, 4, 5, 101, 

101A, and 102. Consistent with the 

NTTAA, the EPA conducted searches to 

identify voluntary consensus standards 

in addition to these EPA methods. No 

applicable voluntary consensus 

standards were identified for EPA 

Methods 1A, 2A, 2D, and 102. The 

search and review results have been 

documented and are placed in the 

docket (No. A–2000–32) for the 

proposed rule.

This search for emissions monitoring 

procedures identified 14 voluntary 

consensus standards and 5 draft 

standards. The EPA determined that the 

14 standards were impractical 

alternatives to EPA test methods for the 

purposes of the proposed rule. 

Therefore, the EPA does not propose to 

adopt these 14 voluntary consensus 

standards in the proposed rule. The 

detailed EPA review comments for these 

14 standards are in the docket for the 

proposed rule (Please see docket No. A–

2000–32). 

The 14 voluntary consensus standards 

are as follows: ASME C00031 or PTC 

19–10–1981, ‘‘Part 10 Flue and Exhaust 

Gas Analyses,’’ for EPA Method 3; 

ASME PTC–38–80 R85 or C00049, 

‘‘Determination of the Concentration of 

Particulate Matter in Gas Streams,’’ for 

EPA Method 5; ASTM D3154–91 (1995), 

‘‘Standard Method for Average Velocity 

in a Duct (Pitot Tube Method),’’ for EPA 

Methods 1, 2, 2C, 3, 3B, and 4; ASTM 

D3464–96, ‘‘Standard Test Method 

Average Velocity in a Duct Using a 

Thermal Anemometer,’’ for EPA Method 

2; ASTM D3685/D3685M–98, ‘‘Test 

Methods for Sampling and 

Determination of Particulate Matter in 

Stack Gases,’’ for EPA Method 5; ASTM 

D3796–90 (1998), ‘‘Standard Practice for 

Calibration of Type S Pitot Tubes,’’ for 

EPA Method 2; ASTM D5835–95, 

‘‘Standard Practice for Sampling 

Stationary Source Emissions for 

Automated Determination of Gas 

Concentration,’’ for EPA Methods 3A; 

ASTM E337–84 (Reapproved 1996), 

‘‘Standard Test Method for Measuring 

Humidity with a Psychrometer (the 

Measurement of Wet- and Dry-Bulb 

Temperatures),’’ for EPA Method 4; 

CAN/CSA Z223.1-M1977, ‘‘Method for 

the Determination of Particulate Mass 

Flows in Enclosed Gas Streams,’’ for 

EPA Method 5; CAN/CSA Z223.2-M86 

(1986), ‘‘Method for the Continuous 

Measurement of Oxygen, Carbon 

Dioxide, Carbon Monoxide, Sulphur 

Dioxide, and Oxides of Nitrogen in 

Enclosed Combustion Flue Gas 

Streams,’’ for EPA Methods 3A; CAN/

CSA Z223.26-M1987, ‘‘Measurement of 

Total Mercury in Air Cold Vapour 

Atomic Absorption 

Spectrophotometeric Method,’’ for EPA 

Methods 101 and 101A; ISO 9096:1992 

(in review 2000), ‘‘Determination of 

Concentration and Mass Flow Rate of 

Particulate Matter in Gas Carrying 

Ducts—Manual Gravimetric Method,’’

for EPA Method 5; ISO 10396:1993, 

‘‘Stationary Source Emissions: Sampling 

for the Automated Determination of Gas 

Concentrations,’’ for EPA Method 3A; 

ISO 10780:1994, ‘‘Stationary Source 

Emissions—Measurement of Velocity 

and Volume Flowrate of Gas Streams in 

Ducts,’’ for EPA Method 2. 

Five of the standards identified in this 

search were not available at the time the 

review was conducted for the purposes 

of the proposed rule because they are 

under development by a voluntary 

consensus body: ASME/BSR MFC 12M, 

‘‘Flow in Closed Conduits Using 

Multiport Averaging Pitot Primary 

Flowmeters,’’ for EPA Method 2; ASME/

BSR MFC 13M, ‘‘Flow Measurement by 

Velocity Traverse,’’ for EPA Method 2 

(and possibly 1); ISO/DIS 12039, 

‘‘Stationary Source Emissions—

Determination of Carbon Monoxide, 

Carbon Dioxide, and Oxygen—

Automated Methods,’’ for EPA Method 

3A; PREN 13211 (1998), ‘‘Air Quality—

Stationary Source Emissions—

Determination of the Concentration of 

Total Mercury,’’ for EPA Methods 101, 

101A (and mercury portion of EPA 

Method 29); and ASTM Z6590Z, 

‘‘Manual Method for Both Speciated and 

Elemental Mercury’’ is a potential 

alternative for portions of EPA Methods 

101A and Method 29 (mercury portion 

only). 

We are not proposing to include these 

five draft voluntary consensus standards 

in the proposed rule. The EPA, 

however, will review the standards 

when they are final. The review 

comments for these five standards are in 

the same docket entry as cited above. 

The EPA takes comment on the 

compliance demonstration requirements 

in the proposed rule and specifically 

invites the public to identify 

potentially-applicable voluntary 

consensus standards. Commenters 

should also explain why the proposed 

rule should adopt these voluntary 

consensus standards in lieu of or in 

addition to EPA’s standards. Emission 

test methods submitted for evaluation 

should be accompanied with a basis for 

the recommendation, including method 

validation data and the procedure used 

to validate the candidate method (if a 

method other than Method 301, 40 CFR 

part 63, appendix A was used). 

Section 63.8232 of the proposed 

standards lists the EPA testing methods 

included in the proposed rule. Under 

§ 63.8 of the NESHAP General 

Provisions, a source may apply to the 

EPA for permission to use alternative 

monitoring in place of any of the EPA 

testing methods. 

I. Executive Order 13211, Actions 

Concerning Regulations That 

Significantly Affect Energy Supply, 

Distribution, or Use 

The proposed rule is not subject to 

Executive Order 13211 (66 FR 28355, 

May 22, 2001) because it is not a 

significant regulatory action under 

Executive Order 12866.

List of Subjects in 40 CFR Part 63 

Environmental protection, Air 

emissions control, Hazardous air 

pollutants, Reporting and recordkeeping 

requirements.

44698 Federal Register / Vol. 67, No. 128 / Wednesday, July 3, 2002 / Proposed Rules 

Dated: June 17, 2002. 

Christine Todd Whitman, 

Administrator.

For the reasons stated in the 

preamble, title 40, chapter I, part 63 of 

the Code of the 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.

2. Part 63 amended by adding Subpart 

IIIII to read as follows:

Subpart IIIII—National Emission 

Standards for Hazardous Air Pollutants 

for Mercury Cell Chlor-Alkali Plants

Sec. 

What This Subpart Covers 

63.8180 What is the purpose of this 

subpart? 

63.8182 Am I subject to this subpart? 

63.8184 What parts of my plant does this 

subpart cover? 

63.8186 When do I have to comply with 

this subpart? 

Emission Limitations and Work Practice 

Standards 

63.8190 What emission limitations must I 

meet? 

63.8192 What work practice standards must 

I meet? 

Operation and Maintenance Requirements 

63.8222 What are my operation and 

maintenance requirements? 

General Compliance Requirements 

63.8226 What are my general requirements 

for complying with this subpart? 

Initial Compliance Requirements 

63.8230 By what date must I conduct 

performance tests or other initial 

compliance demonstrations? 

63.8231 When must I conduct subsequent 

performance tests? 

63.8232 What test methods and other 

procedures must I use to demonstrate 

initial compliance with the emission 

limits? 

63.8234 What equations and procedures 

must I use? 

63.8236 How do I demonstrate initial 

compliance with the emission 

limitations and work practice standards?

Continuous Compliance Requirements 

63.8240 What are my monitoring 

requirements? 

63.8242 What are the installation, 

operation, and maintenance 

requirements for my mercury 

concentration continuous monitoring 

systems? 

63.8244 How do I monitor and collect data 

to demonstrate continuous compliance? 

63.8246 How do I demonstrate continuous 

compliance with the emission 

limitations and work practice standards? 

63.8248 What other requirements must I 

meet to demonstrate continuous 

compliance? 

Notifications, Reports, and Records 

63.8252 What notifications must I submit 

and when? 

63.8254 What reports must I submit and 

when? 

63.8256 What records must I keep? 

63.8258 In what form and how long must I 

keep my records? 

Other Requirements and Information 

63.8262 What parts of the General 

Provisions apply to me? 

63.8264 Who implements and enforces this 

subpart? 

63.8266 What definitions apply to this 

subpart? 

Tables to Subpart IIIII of Part 63 

Table 1 to Subpart IIIII of Part 63—Work 

Practice Standards—Design, Operation, 

and Maintenance Requirements 

Table 2 to Subpart IIIII of Part 63—Work 

Practice Standards—Required Inspections 

Table 3 to Subpart IIIII of Part 63—Work 

Practice Standards—Required Actions for 

Liquid Mercury Spills and Accumulations 

and Hydrogen and Mercury Vapor Leaks 

Table 4 to Subpart IIIII of Part 63—Work 

Practice Standards—Requirements for 

Mercury Liquid Collection 

Table 5 to Subpart IIIII of Part 63—Work 

Practice Standards—Requirements for 

Handling and Storage of MercuryContaining Wastes 

Table 6 to Subpart IIIII of Part 63—Required 

Elements of Washdown Plans 

Table 7 to Subpart IIIII of Part 63—Examples 

of Techniques for Equipment Problem 

Identification, Leak Detection and Mercury 

Vapor Measurements 

Table 8 to Subpart IIIII of Part 63—Required 

Records for Work Practice Standards 

Table 9 to Subpart IIIII of Part 63—

Applicability of General Provisions to 

Subpart IIIII

Subpart IIIII—National Emission 

Standards for Hazardous Air Pollutants 

for Mercury Cell Chlor-Alkali Plants 

What This Subpart Covers

§ 63.8180 What is the purpose of this 

subpart? 

This subpart establishes national 

emission standards for hazardous air 

pollutants (NESHAP) for sources of 

mercury emissions at mercury cell 

chlor-alkali plants. This subpart also 

establishes requirements to demonstrate 

initial and continuous compliance with 

all applicable emission limitations and 

work practice standards in this subpart.

§ 63.8182 Am I subject to this subpart? 

(a) You are subject to this subpart if 

you own or operate a mercury cell 

chlor-alkali plant. 

(b) You are required to obtain a title 

V permit for each source subject to this 

subpart, whether your source is (or is 

part of) a major source of hazardous air 

pollutant (HAP) emissions or an area 

source of HAP emissions. A major 

source of HAP is a plant site that emits 

or has the potential to emit any single 

HAP at a rate of 10 tons or more per year 

or any combination of HAP at a rate of 

25 tons or more per year. An area source 

of HAP is a plant site that has the 

potential to emit HAP but is not a major 

source. 

(c) Beginning on [DATE 2 YEARS 

FROM THE DATE OF PUBLICATION 

OF THE FINAL RULE IN THE Federal 

Register], the provisions of subpart E of 

40 CFR part 61 that apply to mercury 

chlor-alkali plants, which are listed in 

paragraphs (c)(1) through (3) of this 

section, are no longer applicable. 

(1) 40 CFR 61.52(a). 

(2) 40 CFR 61.53 (b) and (c). 

(3) 40 CFR 61.55 (b), (c) and (d).

§ 63.8184 What parts of my plant does this 

subpart cover? 

(a) This subpart applies to each 

affected source at a plant site where 

chlorine and caustic are produced in 

mercury cells. This subpart applies to 

two types of affected sources: the 

mercury cell chlor-alkali production 

facility, as defined in paragraph (a)(1) of 

this section; and the mercury recovery 

facility, as defined in paragraph (a)(2) of 

this section. 

(1) The mercury cell chlor-alkali 

production facility designates an 

affected source consisting of all cell 

rooms and ancillary operations used in 

the manufacture of product chlorine, 

product caustic, and by-product 

hydrogen at a plant site. This subpart 

covers mercury emissions from byproduct hydrogen streams, end-box 

ventilation system vents, and fugitive 

emission sources associated with cell 

rooms, hydrogen systems, caustic 

systems, and storage areas for mercurycontaining wastes.

(2) The mercury recovery facility 

designates an affected source consisting 

of all processes and associated 

operations needed for mercury recovery 

from wastes at a plant site. This subpart 

covers mercury emissions from mercury 

thermal recovery unit vents and fugitive 

emission sources associated with 

storage areas for mercury-containing 

wastes. 

(b) An affected source at your mercury 

cell chlor-alkali plant is existing if you 

commenced construction of the affected 

source before July 3, 2002. 

(c) A mercury recovery facility is a 

new affected source if you commence 

construction or reconstruction of the 

affected source after July 3, 2002. An 

affected source is reconstructed if it 

Federal Register / Vol. 67, No. 128 / Wednesday, July 3, 2002 / Proposed Rules 44699

meets the definition of ‘‘reconstruction’’

in § 63.2.

§ 63.8186 When do I have to comply with 

this subpart? 

(a) If you have an existing affected 

source, you must comply with each 

emission limitation, work practice 

standard, and recordkeeping and 

reporting requirement in this subpart 

that applies to you no later than [DATE 

2 YEARS FROM THE DATE OF 

PUBLICATION OF THE FINAL RULE 

IN THE Federal Register]. 

(b) If you have a new or reconstructed 

mercury recovery facility and its initial 

startup date is on or before [DATE OF 

PUBLICATION OF THE FINAL RULE 

IN THE Federal Register], you must 

comply with each emission limitation, 

work practice standard, and 

recordkeeping and reporting 

requirement in this subpart that applies 

to you by [DATE OF PUBLICATION OF 

THE FINAL RULE IN THE FEDERAL 

REGISTER]. 

(c) If you have a new or reconstructed 

mercury recovery facility and its initial 

startup date is after [DATE OF 

PUBLICATION OF THE FINAL RULE 

IN THE FEDERAL REGISTER], you must 

comply with each emission limitation, 

work practice standard, and 

recordkeeping and reporting 

requirement in this subpart that applies 

to you upon initial startup. 

(d) You must meet the notification 

and schedule requirements in § 63.8252. 

Several of these notifications must be 

submitted before the compliance date 

for your affected source(s). 

Emission Limitations and Work 

Practice Standards

§ 63.8190 What emission limitations must I 

meet? 

(a) Emission limits. You must meet 

each emission limit in paragraphs (a)(1) 

through (3) of this section that applies 

to you. 

(1) New or reconstructed mercury cell 

chlor-alkali production facility. 

Emissions of mercury are prohibited 

from a new or reconstructed mercury 

cell chlor-alkali production facility. 

(2) Existing mercury cell chlor-alkali 

production facility. You must not 

discharge to the atmosphere aggregate 

mercury emissions in excess of the 

applicable limit in paragraph (a)(2)(i) or 

(ii) of this section. 

(i) 0.067 grams of mercury per 

megagram of chlorine produced (1.3 x 

10¥4 pounds of mercury per ton of 

chlorine produced) from all by-product 

hydrogen streams and all end-box 

ventilation system vents when both 

types of emission points are present. 

(ii) 0.033 grams of mercury per 

megagram of chlorine produced (6.59 x 

10¥5 pounds of mercury per ton of 

chlorine produced) from all by-product 

hydrogen streams when there are no 

end-box ventilation systems. 

(3) New, reconstructed, or existing 

mercury recovery facility. You must not 

discharge to the atmosphere mercury 

emissions in excess of the applicable 

limit in paragraph (a)(3)(i) or (ii) of this 

section. 

(i) 23 milligrams per dry standard 

cubic meter from each oven type 

mercury thermal recovery unit vent. 

(ii) 4 milligrams per dry standard 

cubic meter from each non-oven type 

mercury thermal recovery unit vent. 

(b) Operating limits. You must meet 

each operating limit in paragraphs (b)(1) 

and (2) of this section that applies to 

you. 

(1) Existing mercury cell chlor-alkali 

production facility. You must maintain 

the daily average mercury concentration 

in each by-product hydrogen stream no 

higher than the level established during 

the initial performance test. You must 

maintain the daily average mercury 

concentration in each end-box 

ventilation system vent exhaust no 

higher than the level established during 

the initial performance test. 

(2) New, reconstructed, or existing 

mercury recovery facility. You must 

maintain the daily average mercury 

concentration in each oven type 

mercury thermal recovery unit vent 

exhaust no higher than the level 

established during the initial 

performance test. You must maintain 

the daily average mercury concentration 

in each non-oven type mercury thermal 

recovery unit vent exhaust no higher 

than the level established during the 

initial performance test.

§ 63.8192 What work practice standards 

must I meet? 

(a) You must meet the work practice 

standards in Tables 1 through 5 to this 

subpart. 

(b) You must adhere to the response 

intervals specified in Tables 1 through 

5 to this subpart at all times. 

Nonadherence to the intervals in Tables 

1 through 5 to this subpart constitutes 

a deviation and must be documented 

and reported in the compliance report, 

as required by § 63.8254(c), with the 

date and time of the deviation, cause of 

the deviation, a description of the 

conditions, and time actual compliance 

was achieved.

(c) As provided in § 63.6(g), you may 

request to use an alternative to the work 

practice standards in Tables 1 through 

5 to this subpart. 

(d) You must prepare, submit, and 

operate according to a written 

washdown plan designed to minimize 

fugitive mercury emissions through 

routine washing of surfaces where 

liquid mercury could accumulate. The 

written plan must address the elements 

contained in Table to this subpart. 

(e) You must institute a cell room 

monitoring program to continuously 

monitor the elemental mercury vapor 

concentration in the upper portion of 

each cell room against a predetermined 

site-specific action level(s). When a 

mercury concentration is detected that 

exceeds the established action level(s), 

you must identify the cause of the 

elevated concentration and take 

corrective action as quickly as possible. 

At a minimum, these follow-up 

activities should include the relevant 

work practices in Tables 1 through 5 to 

this subpart. You must also keep records 

related to the inspections and corrective 

actions performed. 

Operation and Maintenance 

Requirements

§ 63.8222 What are my operation and 

maintenance requirements? 

As required by § 63.6(e)(1)(i), you 

must always operate and maintain your 

affected source(s), including air 

pollution control and monitoring 

equipment, in a manner consistent with 

good air pollution control practices for 

minimizing emissions at least to the 

levels required by this subpart. 

General Compliance Requirements

§ 63.8226 What are my general 

requirements for complying with this 

subpart? 

(a) You must be in compliance with 

the emission limitations (including 

operating limits) for by-product 

hydrogen streams, end-box ventilation 

system vents, and mercury thermal 

recovery unit vents in § 63.8190 at all 

times, except during periods of startup, 

shutdown, and malfunction. You must 

be in compliance with the applicable 

work practice standards in § 63.8192 at 

all times, except during periods of 

startup, shutdown, and malfunction. 

(b) During the period between the 

compliance date specified for your 

affected source in § 63.8186 and the date 

upon which mercury concentration 

continuous monitoring systems (CMS) 

have been installed and certified and 

any applicable operating limits have 

been set, you must maintain a log 

detailing the operation and maintenance 

of the process and emissions control 

equipment. 

(c) You must develop and implement 

a written startup, shutdown, and 

44700 Federal Register / Vol. 67, No. 128 / Wednesday, July 3, 2002 / Proposed Rules 

malfunction plan (SSMP) according to 

the provisions in § 63.6(e)(3).

Initial Compliance Requirements

§ 63.8230 By what date must I conduct 

performance tests or other initial 

compliance demonstrations? 

(a) As required in § 63.7(a)(2), you 

must conduct a performance test within 

180 calendar days of the compliance 

date that is specified in § 63.8186 for 

your affected source to demonstrate 

initial compliance with the emission 

limits in § 63.8190(a)(2) for by-product 

hydrogen streams and end-box 

ventilation system vents and the 

emission limits in § 63.8190(a)(3) for 

mercury thermal recovery unit vents. 

(b) For each work practice standard in 

§ 63.8192 where initial compliance is 

not demonstrated using a performance 

test, you must demonstrate initial 

compliance within 30 calendar days 

after the compliance date that is 

specified for your affected source in 

§ 63.8186. 

(c) If you commenced construction or 

reconstruction of a mercury recovery 

facility between July 3, 2002 and [DATE 

OF PUBLICATION OF THE FINAL 

RULE IN THE Federal Register, you 

must demonstrate initial compliance 

with either the proposed emission limit 

or the promulgated emission limit no 

later than [DATE 180 DAYS AFTER 

THE DATE OF PUBLICATION OF THE 

FINAL RULE IN THE Federal Register] 

or no later than 180 days after startup 

of the source, whichever is later, 

according to § 63.7(a)(2)(ix). 

(d) If you commenced construction or 

reconstruction of a mercury recovery 

facility between July 3, 2002 and 

[INSERT DATE OF PUBLICATION OF 

THE FINAL RULE IN THE Federal 

Register], and you chose to comply with 

the proposed emission limit when 

demonstrating initial compliance, you 

must conduct a second performance test 

to demonstrate compliance with the 

promulgated emission limit by [DATE 3 

YEARS AND 180 DAYS AFTER THE 

DATE OF PUBLICATION OF THE 

FINAL RULE IN THE Federal Register], 

or after startup of the source, whichever 

is later, according to § 63.7(a)(2)(ix).

§ 63.8231 When must I conduct 

subsequent performance tests? 

You must conduct subsequent 

performance tests to demonstrate 

compliance with the emission limits in 

§ 63.8190(a)(2) for by-product hydrogen 

streams and end-box ventilation system 

vents and the emission limits in 

§ 63.8190(a)(3) for mercury thermal 

recovery unit vents no less frequently 

than twice (at mid-term and renewal) 

during each term of each title V permit.

§ 63.8232 What test methods and other 

procedures must I use to demonstrate 

initial compliance with the emission limits? 

You must conduct a performance test 

for each by-product hydrogen stream, 

end-box ventilation system vent, and 

mercury thermal recovery unit vent 

according to the requirements in 

§ 63.7(e)(1) and the conditions detailed 

in paragraphs (a) through (f) of this 

section. 

(a) You may not conduct performance 

tests during periods of startup, 

shutdown, or malfunction, as specified 

in § 63.7(e)(1). 

(b) For each performance test, you 

must develop a site-specific test plan in 

accordance with § 63.7(c)(2). 

(c) You must conduct at least three 

valid test runs in order to comprise a 

performance test, as specified in 

§ 63.7(e)(3). To be considered a valid 

test run, the sampling time must be at 

least 2 hours and the mercury 

concentration in the field sample must 

be at least 2 times the limit of detection 

for the analytical method. 

(d) You must use the test methods 

specified in paragraphs (d)(1) through 

(4) of this section and the applicable test 

methods in paragraphs (d)(5) through (7) 

of this section. 

(1) Method 1 or 1A in appendix A of 

40 CFR part 60 to determine the 

sampling port locations and the location 

and required number of sampling 

traverse points. 

(2) Method 2, 2A, 2C, or 2D in 

appendix A of 40 CFR part 60 to 

determine the stack gas velocity and 

volumetric flow rate. 

(3) Method 3, 3A, or 3B in appendix 

A of 40 CFR part 60 to determine the 

stack gas molecular weight. 

(4) Method 4 in appendix A of 40 CFR 

part 60 to determine the stack gas 

moisture content. 

(5) For each by-product hydrogen 

stream, Method 102 in appendix A of 40 

CFR part 61 to measure the mercury 

emission rate after the last control 

device. 

(6) For each end-box ventilation 

system vent, Method 101 or 101A in 

appendix A of 40 CFR part 61 to 

measure the mercury emission rate after 

the last control device. 

(7) For each mercury thermal recovery 

unit vent, Method 101 or 101A in 

appendix A of 40 CFR part 61 to 

measure the mercury emission rate after 

the last control device. 

(e) During each test run for a byproduct hydrogen stream and each test 

run for an end-box ventilation system 

vent, you must continuously measure 

the electric current through the 

operating mercury cells and record a 

measurement at least once every 15 

minutes. 

(f) During each test run for a mercury 

thermal recovery unit vent, the mercurycontaining waste processed in the retort 

must be the type of waste that results in 

the highest mercury concentration in 

the mercury thermal recovery unit vent. 

You must document the mercury 

content of this type of waste and an 

explanation of why it results in the 

highest mercury concentration in the 

site-specific test plan required in 

§ 63.8232(b).

§ 63.8234 What equations and procedures 

must I use?

(a) To determine the grams of mercury 

discharged per megagram (grams Hg/Mg 

Cl2) of chlorine produced from all byproduct hydrogen streams and all endbox ventilation system vents, if 

applicable, at a mercury cell chlor-alkali 

production facility, you must follow the 

procedures in paragraphs (a)(1) through 

(6) of this section. 

(1) Determine the mercury emission 

rate for each test run, Rrun, in grams per 

day for each by-product hydrogen 

stream and for each end-box ventilation 

system vent, if applicable, from Method 

101, 101A, or 102 (40 CFR part 61). 

(2) Calculate the average measured 

electric current through the operating 

mercury cells during each test run for 

each by-product hydrogen stream and 

for each end-box ventilation system 

vent, if applicable, using Equation 1 of 

this section as follows:

CL

CL

n avg run

i run

i

n

,

,

= =

∑

1 (Eq. 1)

Where:

CLavg,run = Average measured cell line 

current load during the test run, 

amperes; 

CLi,run = Individual cell line current load 

measurement (i.e., 15 minute 

reading) during the test run, 

amperes; and 

n = Number of cell line current load 

measurements taken over the 

duration of the test run.

(3) Calculate the amount of chlorine 

produced during each test run for each 

by-product hydrogen stream and for 

each end-box ventilation system vent, if 

applicable, using Equation 2 of this 

section as follows:


EP03JY02.000</MATH>
Federal Register / Vol. 67, No. 128 / Wednesday, July 3, 2002 / Proposed Rules 44701

P CL n t Cl run avg run cells run run 2 13 10 6

, ,, = × ( ) . ( )( )( ) − (Eq. 2)

Where:

PCl2, run = Amount of chlorine produced 

during the test run, megagrams 

chlorine (Mg Cl2) ; 

1.3×10¥6 = Theoretical chlorine 

production rate factor, Mg Cl2 per 

hour per ampere per cell; 

CLavg, run = Average measured cell line 

current load during test run, 

amperes, calculated using Equation 

1 of this section; 

ncell, run = Number of cells on-line during 

the test run; and 

trun = Duration of test run, hours. 

(4) Calculate the mercury emission 

rate in grams of mercury per megagram 

of chlorine produced for each test run 

for each by-product hydrogen stream 

and for each end-box ventilation system 

vent, if applicable, using Equation 3 of 

this section as follows:

E

R t

P Hg run

run run

Cl run

,

,

= ( )( )

( )( )















24  2

(Eq. 3)

Where:

EHg, run = Mercury emission rate for the 

test run, grams Hg/Mg Cl2; 

Rrun = Measured mercury emission rate 

for the test run from paragraph 

(a)(1) of this section, grams Hg per 

day; 

trun = Duration of test run, hours; 

24 = Conversion factor, hours per day; 

and 

PCl2, run = Amount of chlorine produced 

during the test run, calculated using 

Equation 2 of this section, Mg Cl2.

(5) Calculate the average mercury 

emission rate for each by-product 

hydrogen stream and for each end-box 

ventilation system vent, if applicable, 

using Equation 4 of this section as 

follows:

E

E

n HG avg

Hg run

i l

n

,

,

= =

∑

(Eq. 4)

Where:

EHg,avg = Average mercury emission rate 

for the by-product hydrogen stream 

or the end-box ventilation system 

vent, if applicable, grams HMg Cl2; 

EHg,run = Mercury emission rate for each 

test run for the by-product 

hydrogen stream or the end-box 

ventilation system vent, if 

applicable, grams Hg/Mg Cl2, 

calculated using Equation 3 of this 

section; and 

n = Number of test runs conducted for 

the by-product hydrogen stream or 

the end-box ventilation system 

vent, if applicable.

(6) Calculate the total mercury 

emission rate from all by-product 

hydrogen streams and all end-box 

ventilation system vents, if applicable, 

at the mercury cell chlor-alkali 

production facility using Equation 5 of 

this section as follows:

E E Hg H EB Hg avg

i

n

, , 2

1

=

=

∑ (Eq. 5)

Where:

EHg,H2EB = Total mercury emission rate 

from all by-product hydrogen 

streams and all end-box ventilation 

system vents, if applicable, at the 

affected source, grams Hg/Mg Cl2; 

EHg,avg = Average mercury emission rate 

for each by-product hydrogen 

stream and each end-box 

ventilation system vent, if 

applicable, grams Hg/Mg Cl2, 

determined using Equation 4 of this 

section; and 

n = total number of by-product 

hydrogen streams and end-box 

ventilation system vents at the 

affected source.

(b) To determine the milligrams of 

mercury per dry standard cubic meter 

exhaust discharged from mercury 

thermal recovery unit vents, you must 

follow the procedures in paragraphs 

(b)(1) and (2) of this section. 

(1) Calculate the concentration of 

mercury in milligrams of mercury per 

dry standard cubic meter of exhaust for 

each test run for each mercury thermal 

recovery unit vent using Equation 6 of 

this section as follows:

C

m

V Hg run

Hg

m std

, = ( )( )

( )





















−

( )

10 3

(Eq. 6)

Where:

CHg, run = Mercury concentration for the 

test run, milligrams of mercury per 

dry standard cubic meter of 

exhaust; 

mHg = Mass of mercury in test run 

sample, from Method 101, 101A, or 

102, micrograms; 

10¥3 = Conversion factor, milligrams 

per microgram; and 

Vm(std) = Dry gas sample volume at 

standard conditions, from Method 

101, 101A, or 102, dry standard 

cubic meters.

(2) Calculate the average 

concentration of mercury in each 

mercury thermal recovery unit vent 

exhaust using Equation 7 of this section 

as follows:

C

C

n Hg avg

Hg run

i

n

,

,

= =

∑

1 (Eq. 7)

Where:

CHg,avg = Average mercury concentration 

for the mercury thermal recovery 

unit vent, milligrams of mercury 

per dry standard cubic meter 

exhaust; 

CHg,run = Mercury concentration for each 

test run, milligrams of mercury per 

dry standard cubic meter of 

exhaust, calculated using Equation 

6 of this section; and 

n = Number of test runs conducted for 

the mercury thermal recovery unit 

vent.

(c) For each by-product hydrogen 

stream, each end-box ventilation system 

vent, and each mercury thermal 

recovery unit vent, you must establish a 

site-specific mercury concentration 

operating limit according to the 

procedures in paragraphs (c)(1) and (2) 

of this section. 

(1) Using a mercury concentration 

CMS required in § 63.8240, measure and 

record the elemental mercury 

concentration after the last control 

device at least once every 15 minutes for 

the entire duration of each performance 

test run. 

(2) Calculate the mercury 

concentration operating limit based on 

the mercury concentration monitoring 

data obtained during each valid test run 

of the performance test during which 

the mercury emissions did not exceed 

the applicable mercury emission limit 

in § 63.8190(a)(2) through (3) using 

Equation 8 of this section as follows:

OL

C

n Hgconc

Hg i

i

n

=











 =

∑ ,

1 (Eq. 8)

Where:

OLHgconc = Mercury concentration 

operating limit, ppmv or 

concentration units selected by the 

owner/operator; 

CHg,i = Concentration of elemental 

mercury measured at the interval i 

(i.e., 15 minute reading) during 

each valid test run of the 

performance test during which the 

mercury emissions did not exceed 

the applicable mercury emission 


EP03JY02.001</MATH> EP03JY02.002</MATH> EP03JY02.003</MATH> EP03JY02.004</MATH> EP03JY02.005</MATH> EP03JY02.006</MATH> EP03JY02.007</MATH>
44702 Federal Register / Vol. 67, No. 128 / Wednesday, July 3, 2002 / Proposed Rules 

limit in § 63.8190(a)(2) through (3) 

using a mercury concentration 

CMS, ppmv or concentration units 

selected by the owner/operator; and 

n = Number of concentration 

measurements taken during all test 

runs of the performance test.

(d) You may change a mercury 

concentration operating limit by 

following the requirements in 

paragraphs (d)(1) through (3) of this 

section. 

(1) Submit a written notification to 

the Administrator of your intent to 

conduct a new performance test to 

revise the mercury concentration 

operating limit at least 60 calendar days 

before the test is scheduled to begin. 

(2) Conduct a performance test and 

demonstrate compliance with the 

applicable emission limit. 

(3) Establish a revised mercury 

concentration operating limit according 

to the procedures in paragraph (c) of 

this section. 

(e) You must calculate the daily 

average elemental mercury 

concentration using Equation 9 of this 

section as follows:

C

C

n Hg dailyavg

Hg i

i

n

,

,

=











 =

∑

1 (Eq. 9)

Where:

CHg,dailyavg = Average elemental mercury 

concentration for the operating day, 

ppmv or concentration units 

selected by the owner/operator; 

CHg,i = Concentration of elemental 

mercury measured at the interval i 

(i.e., 15 minute reading) using a 

mercury concentration CMS, ppmv 

or concentration units selected by 

the owner/operator; and 

n = Number of concentration 

measurements taken during the 

operating day.

§ 63.8236 How do I demonstrate initial 

compliance with the emission limitations 

and work practice standards? 

(a) For each mercury cell chlor-alkali 

production facility, you have 

demonstrated initial compliance with 

the emission limits for by-product 

hydrogen streams and end-box 

ventilation system vents in 

§ 63.8190(a)(2) if:

(1) Total mercury emission rate from 

all by-product hydrogen streams and all 

end-box ventilation system vents, if 

applicable, at the affected source, 

determined in accordance with 

§§ 63.8232 and 63.8234(a), did not 

exceed the applicable emission limit in 

§ 63.8190(a)(2)(i) or (ii); and 

(2) You have established a mercury 

concentration operating limit for each 

by-product hydrogen stream and each 

end-box ventilation system vent, if 

applicable, in accordance with 

§ 63.8234(c), and have a record of all 

mercury concentration monitoring data 

used to establish the limit. 

(b) For each mercury recovery facility, 

you have demonstrated initial 

compliance with the emission limits for 

mercury thermal recovery unit vents in 

§ 63.8190(a)(3) if: 

(1) Mercury concentration in each 

mercury thermal recovery unit vent 

exhaust, determined in accordance with 

§§ 63.8232 and 63.8234(b), did not 

exceed the applicable emission limit in 

§ 63.8190(a)(3)(i) or (ii); and 

(2) You have established a mercury 

concentration operating limit for each 

mercury thermal recovery unit vent in 

accordance with § 63.8234(c) and have a 

record of all mercury concentration 

monitoring data used to establish the 

limit. 

(c) For each affected source, you have 

demonstrated initial compliance with 

the work practice standards in § 63.8192 

if you certify in your Notification of 

Compliance Status that you meet or will 

meet each of the work practice 

standards, if you prepare the washdown 

plan and mercury vapor measurement 

plan and submit them as part of your 

Notification of Compliance Status, and 

if you certify in the notification that you 

operate according to or will operate 

according to the plan. 

(d) You must submit the Notification 

of Compliance Status containing the 

results of the initial compliance 

demonstration according to the 

requirements in § 63.8252(e). 

Continuous Compliance Requirements

§ 63.8240 What are my monitoring 

requirements? 

For each by-product hydrogen stream, 

each end-box ventilation system vent, 

and each mercury thermal recovery unit 

vent, you must continuously monitor 

the elemental mercury concentration 

using a mercury concentration CMS 

monitor according to the requirements 

in § 63.8242.

§ 63.8242 What are the installation, 

operation, and maintenance requirements 

for my mercury concentration continuous 

monitoring systems? 

You must install, operate, and 

maintain each mercury concentration 

CMS according to paragraphs (a) 

through (e) of this section. 

(a) Each mercury concentration CMS 

must sample, analyze, and record the 

concentration of elemental mercury at 

least once every 15 minutes. 

(b) Each mercury concentration CMS 

analyzer must have a detector with the 

capability to detect an elemental 

mercury concentration at or below 0.5 

times the mercury concentration 

operating limit established in 

§ 63.8234(c). 

(c) In lieu of a promulgated 

performance specification as required in 

§ 63.8(a)(2), you must develop a sitespecific monitoring plan that addresses 

the elements in paragraphs (c)(1) 

through (6) of this section. 

(1) Installation and measurement 

location downstream of the last control 

device for each by-product hydrogen 

stream, end-box ventilation system vent, 

and mercury thermal recovery unit vent. 

(2) Performance and equipment 

specifications for the sample interface, 

the pollutant concentration analyzer, 

and the data collection and reduction 

system. 

(3) Performance evaluation 

procedures and acceptance criteria (i.e., 

calibrations). 

(4) Ongoing operation and 

maintenance procedures in accordance 

with the requirements of § 63.8(c)(1), 

(3), and (4)(ii). 

(5) Ongoing data quality assurance 

procedures in accordance with the 

requirements of § 63.8(d). 

(6) Ongoing recordkeeping and 

reporting procedures in accordance the 

general requirements of § 63.10(c), 

(e)(1), and (e)(2)(i).

(d) You must conduct a performance 

evaluation of each mercury 

concentration CMS in accordance with 

your site-specific monitoring plan. 

(e) You must operate and maintain 

each mercury concentration CMS in 

continuous operation according to the 

site-specific monitoring plan.

§ 63.8244 How do I monitor and collect 

data to demonstrate continuous 

compliance? 

(a) Except for monitor malfunctions, 

associated repairs, and required quality 

assurance or control activities 

(including, as applicable, calibration 

checks and required zero and span 

adjustments), you must monitor 

elemental mercury concentration 

continuously (or collect data at all 

required intervals) at all times that the 

affected source is operating. 

(b) You may not use data recorded 

during monitoring malfunctions, 

associated repairs, and required quality 

assurance or control activities in data 

averages and calculations used to report 

emission or operating levels or to fulfill 

a minimum data availability 

requirement, if applicable. You must 

use all the data collected during all 

other periods in assessing compliance. 

(c) A monitoring malfunction is any 

sudden, infrequent, not reasonably 


EP03JY02.008</MATH>
Federal Register / Vol. 67, No. 128 / Wednesday, July 3, 2002 / Proposed Rules 44703

preventable failure of the monitoring to 

provide valid data. Monitoring failures 

that are caused in part by poor 

maintenance or careless operation are 

not malfunctions.

§ 63.8246 How do I demonstrate 

continuous compliance with the emission 

limitations and work practice standards? 

(a) For each by-product hydrogen 

stream, each end-box ventilation system 

vent, and each mercury thermal 

recovery unit vent, you must 

demonstrate continuous compliance 

with each mercury concentration 

operating limit by: 

(1) Collecting mercury concentration 

data according to § 63.8244(a), 

representing at least 90 percent of the 15 

minute periods in the operating day 

(with data recorded during monitoring 

malfunctions, associated repairs, and 

required quality assurance or control 

activities not counting toward the 90 

percent requirement); 

(2) Reducing the mercury 

concentration data to daily averages 

using Equation 9 of § 63.8234(e), not 

including data recorded during 

monitoring malfunctions, associated 

repairs, and required quality assurance 

or control activities; 

(3) Maintaining the daily average 

elemental mercury concentration no 

higher than the mercury concentration 

operating limit established in 

§ 63.8234(c); and 

(4) Maintaining records of mercury 

concentration monitoring and daily 

average values, as required in 

§ 63.8256(b)(3) and (4).

(b) You must demonstrate continuous 

compliance with the work practice 

standards in § 63.8192 by maintaining 

records in accordance with § 63.8256(c).

§ 63.8248 What other requirements must I 

meet to demonstrate continuous 

compliance? 

(a) Deviations. You must report each 

instance in which you did not meet 

each emission limitation in § 63.8190 

that applies to you. This includes 

periods of startup, shutdown, and 

malfunction. You also must report each 

instance in which you did not meet 

each work practice standard in 

§ 63.8192 that applies to you. These 

instances are deviations from the 

emission limitations and work practice 

standards in this subpart. These 

deviations must be reported according 

to the requirements in § 63.8254. 

(b) Startups, shutdowns, and 

malfunctions. During periods of startup, 

shutdown, and malfunction, you must 

operate in accordance with your startup, 

shutdown, and malfunction plan 

required in § 63.8226(c). 

(1) Consistent with §§ 63.6(e) and 

63.7(e)(1), deviations that occur during 

a period of startup, shutdown, or 

malfunction are not violations if you 

demonstrate to the Administrator’s 

satisfaction that you were operating in 

accordance with the startup, shutdown, 

and malfunction plan. 

(2) The Administrator will determine 

whether deviations that occur during a 

period of startup, shutdown, or 

malfunction are violations, according to 

the provisions in § 63.6(e). 

Notification, Reports, and Records

§ 63.8252 What notifications must I submit 

and when? 

(a) You must submit all of the 

notifications in §§ 63.7(b) and (c), 

63.8(e), (f) and 63.9(b) through (h) that 

apply to you by the dates specified. 

(b) As specified in § 63.9(b)(2), if you 

start up your affected source before 

[DATE OF PUBLICATION OF THE 

FINAL RULE IN THE Federal Register], 

you must submit your initial 

notification not later than [DATE 120 

DAYS AFTER THE DATE OF 

PUBLICATION OF THE FINAL RULE 

IN THE Federal Register]. 

(c) As specified in § 63.9(b)(3), if you 

start up your new or reconstructed 

mercury recovery facility on or after 

[DATE OF PUBLICATION OF THE 

FINAL RULE IN THE Federal Register], 

you must submit your initial 

notification not later than 120 days after 

you become subject to this subpart. 

(d) For each performance test that you 

are required to conduct for by-product 

hydrogen streams and end-box 

ventilation system vents and for 

mercury thermal recovery unit vents, 

you must submit a notification of intent 

to conduct a performance test at least 60 

calendar days before the performance 

test is scheduled to begin as required in 

§ 63.7(b)(1).

(e) You must submit a Notification of 

Compliance Status in accordance with 

paragraphs (e)(1) and (2) of this section. 

(1) For each initial compliance 

demonstration that does not include a 

performance test, you must submit the 

Notification of Compliance Status before 

the close of business on the 30th 

calendar day following the completion 

of the initial compliance demonstration. 

This Notification of Compliance Status 

must certify that you meet or will meet 

each work practice standard in 

§ 63.8192. The washdown plan must 

also be submitted, and the Notification 

of Compliance Status must certify that 

you operate according to or will operate 

according to the plan. 

(2) For each initial compliance 

demonstration that does include a 

performance test, you must submit the 

Notification of Compliance Status, 

including the performance test results, 

before the close of business on the 60th 

calendar day following the completion 

of the performance test according to 

§ 63.10(d)(2). The Notification of 

Compliance Status must contain the 

information in § 63.9(h)(2)(ii)(A) 

through (G). The site-specific 

monitoring plan required in § 63.8242(c) 

must also be submitted.

§ 63.8254 What reports must I submit and 

when? 

(a) Compliance report due dates. 

Unless the Administrator has approved 

a different schedule, you must submit a 

semiannual compliance report to your 

permitting authority according to the 

requirements in paragraphs (a)(1) 

through (5) of this section. 

(1) The first compliance report must 

cover the period beginning on the 

compliance date that is specified for 

your affected source in § 63.8186 and 

ending on June 30 or December 31, 

whichever date comes first after the 

compliance date that is specified for 

your affected source in § 63.8186. 

(2) The first compliance report must 

be postmarked or delivered no later than 

July 31 or January 31, whichever date 

comes first after your first compliance 

report is due. 

(3) Each subsequent compliance 

report must cover the semiannual 

reporting period from January 1 through 

June 30 or the semiannual reporting 

period from July 1 through December 

31. 

(4) Each subsequent compliance 

report must be postmarked or delivered 

no later than July 31 or January 31, 

whichever date comes first after the end 

of the semiannual reporting period. 

(5) For each affected source, if your 

title V permitting authority has 

established dates for submitting 

semiannual reports pursuant to 40 CFR 

70.6(a)(3)(iii)(A) or 40 CFR 

71.6(a)(3)(iii)(A), you may submit the 

first and subsequent compliance reports 

according to the dates the permitting 

authority has established instead of 

according to the dates in paragraphs 

(a)(1) through (4) of this section. 

(b) Compliance report contents. Each 

compliance report must contain the 

information in paragraphs (b)(1) through 

(3) of this section, and as applicable, 

paragraphs (b)(4) through (8) of this 

section. 

(1) Company name and address. 

(2) Statement by a responsible official, 

with that official’s name, title, and 

signature, certifying the truth, accuracy, 

and completeness of the content of the 

report. 

44704 Federal Register / Vol. 67, No. 128 / Wednesday, July 3, 2002 / Proposed Rules 

(3) Date of report and beginning and 

ending dates of the reporting period. 

(4) If you had a startup, shutdown or 

malfunction during the reporting period 

and you took actions consistent with 

your startup, shutdown, and 

malfunction plan, the compliance report 

must include the information in 

§ 63.10(d)(5)(i). 

(5) If there were no deviations from 

the continuous compliance 

requirements in § 63.8246 that apply to 

you, a statement that there were no 

deviations from the emission limitations 

and work practice standards during the 

reporting period. 

(6) If there were no periods during 

which the mercury concentration CMS 

was out-of-control as specified in 

§ 63.8(c)(7), a statement that there were 

no periods during the which the 

mercury concentration CMS was out-ofcontrol during the reporting period. 

(7) For each deviation from the 

requirements for work practice 

standards in Tables 1 through 5 to this 

subpart that occurs at an affected source 

(including deviations where the 

response intervals were not adhered to 

as described in § 63.8192(c)), the 

compliance report must contain the 

information in paragraphs (b)(1) through 

(4) of this section and the information 

in paragraphs (b)(7)(i) and (ii) of this 

section. This includes periods of 

startup, shutdown, and malfunction. 

(i) The total operating time of each 

affected source during the reporting 

period. 

(ii) Information on the number, 

duration, and cause of deviations 

(including unknown cause, if 

applicable), as applicable, and the 

corrective action taken. 

(8) For each deviation from an 

emission limitation (emission limit and 

operating limit) occurring at an affected 

source where you are using a mercury 

concentration CMS, in accordance with 

the site-specific monitoring plan 

required in § 63.8242(c), to comply with 

the emission limitation in this subpart, 

you must include the information in 

paragraphs (b)(1) through (4) of this 

section and the information in 

paragraphs (b)(8)(i) through (xii) of this 

section. This includes periods of 

startup, shutdown, and malfunction. 

(i) The date and time that each 

malfunction started and stopped. 

(ii) The date and time of each instance 

in which a continuous monitoring 

system was inoperative, except for zero 

(low-level) and high-level checks. 

(iii) The date, time, and duration of 

each instance in which a continuous 

monitoring system was out-of-control, 

including the information in 

§ 63.8(c)(8). 

(iv) The date and time that each 

deviation started and stopped, and 

whether each deviation occurred during 

a period of startup, shutdown, or 

malfunction or during another period. 

(v) A summary of the total duration of 

the deviation during the reporting 

period and the total duration as a 

percent of the total source operating 

time during that reporting period. 

(vi) A breakdown of the total duration 

of the deviations during the reporting 

period including those that are due to 

startup, shutdown, control equipment 

problems, process problems, other 

known causes, and other unknown 

causes. 

(vii) A summary of the total duration 

of continuous monitoring system 

downtime during the reporting period 

and the total duration of monitoring 

system downtime as a percent of the 

total source operating time during the 

reporting period. 

(viii) An identification of each 

hazardous air pollutant that was 

monitored at the affected source. 

(ix) A brief description of the process 

units. 

(x) A brief description of the 

continuous monitoring system. 

(xi) The date of the latest continuous 

monitoring system certification or audit. 

(xii) A description of any changes in 

monitoring system, processes, or 

controls since the last reporting period. 

(c) Immediate startup, shutdown, and 

malfunction report. If you had a startup, 

shutdown, or malfunction during the 

semiannual reporting period that was 

not consistent with your startup, 

shutdown, and malfunction plan 

required in § 63.8226(c), you must 

submit an immediate startup, shutdown, 

and malfunction report according to the 

requirements in § 63.10(d)(5)(ii). 

(d) Part 70 monitoring report. For 

each affected source, you must report all 

deviations as defined in this subpart in 

the semiannual monitoring report 

required by 40 CFR 70.6(a)(3)(iii)(A) or 

40 CFR 71.6(a)(3)(iii)(A). If you submit 

a compliance report for an affected 

source along with, or as part of, the 

semiannual monitoring report required 

by 40 CFR 70.6(a)(3)(iii)(A) or 40 CFR 

71.6(a)(3)(iii)(A), and the compliance 

report includes all required information 

concerning deviations from any 

emission limitation and work practice 

standard in this subpart, submission of 

the compliance report satisfies any 

obligation to report the same deviations 

in the semiannual monitoring report. 

However, submission of a compliance 

report does not otherwise affect any 

obligation you may have to report 

deviations from permit requirements for 

an affected source to your permitting 

authority.

§ 63.8256 What records must I keep? 

(a) General records. You must keep 

the records in paragraphs (a)(1) and (2) 

of this section. 

(1) A copy of each notification and 

report that you submitted to comply 

with this subpart, including all 

documentation supporting any initial 

notification or notification of 

compliance status that you submitted, 

according to the requirements in 

§ 63.10(b)(2)(xiv). 

(2) The records in § 63.6(e)(3)(iii) 

through (v) related to startup, shutdown, 

and malfunction. 

(b) Records associated with the byproduct hydrogen stream and end-box 

ventilation system vent emission 

limitations and the mercury thermal 

recovery unit vent emission limitations. 

You must keep the records in 

paragraphs (b)(1) through (5) of this 

section related to the emission 

limitations in § 63.8190(a)(2) through (3) 

and (b). 

(1) Records of performance tests as 

required in § 63.10(b)(2)(viii). 

(2) Records of the establishment of the 

applicable mercury concentration 

operating limits, including records of 

the mercury concentration monitoring 

conducted during the performance tests. 

(3) Records of the continuous mercury 

concentration monitoring data. 

(4) Records of the daily average 

elemental mercury concentration 

values. 

(5) Records associated with your sitespecific monitoring plan required in 

§ 63.8242(c) (i.e., results of inspections, 

calibrations, and validation checks of 

each mercury concentration CMS). 

(c) Records associated with the work 

practice standards. You must keep the 

records specified in Table 8 to this 

subpart related to the work practice 

standards in Tables 1 through 5 to this 

subpart. You must also maintain a copy 

of your current washdown plan and 

records of when each washdown occurs.

§ 63.8258 In what form and how long must 

I keep my records? 

(a) Your records must be in a form 

suitable and readily available for 

expeditious review, according to 

§ 63.10(b)(1).

(b) As specified in § 63.10(b)(1), you 

must keep each record for 5 years 

following the date of each occurrence, 

measurement, maintenance, corrective 

action, report, or record. 

(c) You must keep each record on site 

for at least 2 years after the date of each 

occurrence, measurement, maintenance, 

corrective action, report, or record, 

Federal Register / Vol. 67, No. 128 / Wednesday, July 3, 2002 / Proposed Rules 44705

according to § 63.10(b)(1). You can keep 

the records offsite for the remaining 3 

years. 

Other Requirements and Information

§ 63.8262 What parts of the General 

Provisions apply to me? 

Table 9 to this subpart shows which 

parts of the General Provisions in 

§§ 63.1 through 63.13 apply to you.

§ 63.8264 Who implements and enforces 

this subpart? 

(a) This subpart can be implemented 

and enforced by us, the United States 

Environmental Protection Agency (U.S. 

EPA), or a delegated authority such as 

your State, local, or tribal agency. If the 

U.S. EPA Administrator has delegated 

authority to your State, local, or tribal 

agency, then that agency has the 

authority to implement and enforce this 

subpart. You should contact your U.S. 

EPA Regional Office to find out if this 

subpart is delegated to your State, local, 

or tribal agency. 

(b) In delegating implementation and 

enforcement authority of this subpart to 

a State, local, or tribal agency under 

subpart E of this part, the authorities 

contained in paragraph (c) of this 

section are retained by the 

Administrator of U.S. EPA and are not 

transferred to the State, local, or tribal 

agency. 

(c) The authorities in paragraphs (c)(1) 

through (4) of this section will not be 

delegated to State, local, or tribal 

agencies. 

(1) Approval of alternatives under 

§ 63.6(g) to the non-opacity emission 

limitations in § 63.8190 and work 

practice standards in § 63.8192. 

(2) Approval of major alternatives to 

test methods under § 63.7(e)(2)(ii) and 

(f) and as defined in § 63.90. 

(3) Approval of major alternatives to 

monitoring under § 63.8(f) and as 

defined in § 63.90. 

(4) Approval of major alternatives to 

recordkeeping and reporting under 

§ 63.10(f) and as defined in § 63.90.

§ 63.8266 What definitions apply to this 

subpart? 

Terms used in this subpart are 

defined in the Clean Air Act, in § 63.2, 

and in this section as follows: 

Aqueous liquid means a liquid 

mixture in which water is the 

predominant component. 

Brine means an aqueous solution of 

alkali metal chloride, as sodium 

chloride salt solution or potassium 

chloride salt solution, that is used in the 

electrolyzer as a raw material.

By-product hydrogen stream means 

the hydrogen gas from each decomposer 

that passes through the hydrogen system 

and is burned as fuel, transferred to 

another process as raw material, or 

discharged directly to the atmosphere. 

Caustic means an aqueous solution of 

alkali metal hydroxide, as sodium 

hydroxide or potassium hydroxide, that 

is produced in the decomposer. 

Caustic basket means a fixture 

adjacent to the decomposer that 

contains a serrated funnel over which 

the caustic from the decomposer passes, 

breaking into droplets such that electric 

current is interrupted. 

Caustic system means all vessels, 

piping, and equipment that convey 

caustic and remove mercury from the 

caustic stream. The caustic system 

begins at the decomposer and ends after 

the primary filters. 

Cell room means a building or other 

structure in which one or more mercury 

cells are located. 

Control device means a piece of 

equipment (such as condensers, coolers, 

chillers, heat exchangers, mist 

eliminators, absorption units, and 

adsorption units) that removes mercury 

from gaseous streams. 

Decomposer means the component of 

a mercury cell in which mercury 

amalgam and water react in bed of 

graphite packing (within a cylindrical 

vessel), producing caustic and hydrogen 

gas and returning mercury to its 

elemental form for re-use in the process. 

Deviation means any instance in 

which an affected source subject to this 

subpart, or an owner or operator of such 

a source: 

(1) Fails to meet any requirement or 

obligation established by this subpart 

including, but not limited to, any 

emission limitation (including any 

operating limit) or work practice 

standard; 

(2) Fails to meet any term or condition 

that is adopted to implement an 

applicable requirement in this subpart 

and that is included in the operating 

permit for any affected source required 

to obtain such a permit; or 

(3) Fails to meet any emission 

limitation (including any operating 

limit) or work practice standard in this 

subpart during startup, shutdown, or 

malfunction, regardless or whether or 

not such failure is permitted by this 

subpart. 

Electrolyzer means the main 

component of the mercury cell that 

consists of an elongated, shallow steel 

trough that holds a layer of mercury as 

a flowing cathode. The electrolyzer is 

enclosed by side panels and a top that 

suspends metal anodes. In the 

electrolyzer, brine is fed between a 

flowing mercury cathode and metal 

anodes in the presence of electricity to 

produce chlorine gas and an alkali 

metal-mercury amalgam (mercury 

amalgam).

Emission limitation means any 

emission limit or operating limit. 

End box means a component of a 

mercury cell for transferring materials 

between the electrolyzer and the 

decomposer. The inlet end box collects 

and combines raw materials at the inlet 

end of the cell, and the outlet end box 

separates and directs various materials 

either into the decomposer or out of the 

cell. 

End-box ventilation system means all 

vessels, piping, and equipment that 

evacuate the head space of each 

mercury cell end box (and possibly 

other vessels and equipment) to the 

atmosphere. The end-box ventilation 

system begins at the end box (and other 

vessel or equipment which is being 

evacuated) and terminates at the endbox ventilation system vent. The endbox ventilation system includes all 

control devices. 

End-box ventilation system vent

means the discharge point of the endbox ventilation system to the 

atmosphere after all control devices. 

Hydrogen leak means hydrogen gas 

(containing mercury vapor) that is 

escaping from the decomposer or 

hydrogen system. 

Hydrogen system means all vessels, 

piping, and equipment that convey a byproduct hydrogen stream. The hydrogen 

system begins at the decomposer and 

ends at the point where the by-product 

hydrogen stream is either burned as 

fuel, transferred to another process as 

raw material, or discharged directly to 

the atmosphere. The hydrogen system 

includes all control devices. 

In liquid mercury service means 

containing or coming in contact with 

liquid mercury. 

Liquid mercury accumulation means 

one or more liquid mercury droplets, or 

a pool of liquid mercury, present on the 

floor or other surface exposed to the 

atmosphere. 

Liquid mercury leak means the liquid 

mercury that is dripping or otherwise 

escaping from process equipment. 

Liquid mercury spill means a liquid 

mercury accumulation resulting from a 

liquid mercury that leaked from process 

equipment or that dripped during 

maintenance or handling. 

Mercury cell means a device 

consisting of an electrolyzer and 

decomposer, with one or more end 

boxes, a mercury pump, and other 

components linking the electrolyzer and 

decomposer. 

Mercury cell amalgam seal pot means 

a compartment through which mercury 

amalgam passes from an outlet end box 

to a decomposer. 

44706 Federal Register / Vol. 67, No. 128 / Wednesday, July 3, 2002 / Proposed Rules 

Mercury cell chlor-alkali plant means 

all contiguous or adjoining property that 

is under common control, where 

mercury cells are used to manufacture 

product chlorine, product caustic, and 

by-product hydrogen and where 

mercury may be recovered from wastes. 

Mercury cell chlor-alkali production 

facility means an affected source 

consisting of all cell rooms and ancillary 

operations used in the manufacture of 

product chlorine, product caustic, and 

by-product hydrogen at a mercury cell 

chlor-alkali plant. 

Mercury concentration CMS, or 

mercury concentration continuous 

monitoring system, means a CMS, as 

defined in § 63.2, that continuously 

measures the concentration of mercury. 

Mercury-containing wastes means 

waste materials containing mercury, 

which are typically classified under 

Resource Conservation and Recovery 

Act (RCRA) solid waste designations. 

K071 wastes are sludges from the brine 

system. K106 are wastewater treatment 

sludges. D009 wastes are non-specific 

mercury-containing wastes, further 

classified as either debris or nondebris 

(i.e., cell room sludges and carbon from 

decomposers). 

Mercury pump means a component of 

a mercury cell for conveying elemental 

mercury re-created in the decomposer to 

the beginning of the mercury cell. A 

mercury pump is typically found either 

as an in-line mercury pump (near a 

mercury suction pot or mercury seal 

pot) or submerged mercury pump 

(within a mercury pump tank or 

mercury pump seal). 

Mercury recovery facility means an 

affected source consisting of all 

processes and associated operations 

needed for mercury recovery from 

wastes at a mercury cell chlor-alkali 

plant. 

Mercury thermal recovery unit means 

the retort(s) where mercury-containing 

wastes are heated to volatilize mercury 

and the mercury recovery/control 

system (control devices and other 

equipment) where the retort off-gas is 

cooled, causing mercury to condense 

and liquid mercury to be recovered. 

Mercury thermal recovery unit vent

means the discharge point of the 

mercury thermal recovery unit to the 

atmosphere after all recovery/control 

devices. This term encompasses both 

oven type vents and non-oven type 

vents. 

Mercury vacuum cleaner means a 

cleanup device used to draw a liquid 

mercury spill or accumulation (via 

suction pressure) into a closed 

compartment. 

Non-oven type mercury thermal 

recovery unit vent means the discharge 

point to the atmosphere after all 

recovery/control devices of a mercury 

thermal recovery unit in which the 

retort is either a rotary kiln or single 

hearth retort. 

Open-top container means any 

container that does not have a tightfitting cover that keeps its contents from 

being exposed to the atmosphere.

Oven type mercury thermal recovery 

unit vent means the discharge point to 

the atmosphere after all recovery/

control devices of a mercury thermal 

recovery unit in which each retort is a 

batch oven retort. 

Responsible official means 

responsible official as defined in 40 CFR 

70.2. 

Retort means a furnace where 

mercury-containing wastes are heated to 

drive mercury into the gas phase. The 

types of retorts used as part of mercury 

thermal recovery units at mercury cell 

chlor-alkali plants include batch oven 

retorts, rotary kilns, and single hearth 

retorts. 

Spalling means fragmentation by 

chipping. 

Sump means a large reservoir or pit 

for wastewaters (primarily washdown 

waters). 

Trench means a narrow channel or 

depression built into the length of a cell 

room floor that leads washdown 

materials to a drain. 

Vent hose means a connection for 

transporting gases from the mercury 

cell. 

Washdown means the act of rinsing a 

floor or surface with a stream of aqueous 

liquid to cleanse it of a liquid mercury 

spill or accumulation, generally by 

driving it into a trench. 

Work practice standard means any 

design, equipment, work practice, or 

operational standard, or combination 

thereof, that is promulgated pursuant to 

section 112(h) of the Clean Air Act. 

Tables to Subpart IIIII of Part 63

As stated in § 63.8192, you must meet 

the work practice standards in the 

following table:

TABLE 1 TO SUBPART IIIII OF PART 63—WORK PRACTICE STANDARDS—DESIGN, OPERATION, AND MAINTENANCE

REQUIREMENTS

For . . . You must . . . 

1. Cell rooms ........................................... a. Construct each cell room interior using materials that are resistant to absorption of mercury, resistant to corrosion, facilitate the detection of liquid mercury spills or accumulations, and are easy to 

clean. 

b. Limit access around and beneath mercury cells in each cell room to prevent liquid mercury from 

being tracked into other areas. 

c. Provide adequate lighting in each cell room to facilitate the detection of liquid mercury spills or accumulations. 

d. Minimize the number of items stored in each cell room. 

2. Mercury cells and electrolyzers ........... a. Operate and maintain each electrolyzer, decomposer, end box, and mercury pump to minimize 

leakage of mercury. 

b. Prior to opening an electrolyzer for maintenance, do the following: (1) complete work that can be 

done before opening the electrolyzer in order to minimize the time required to complete maintenance when the electrolyzer is open (e.g., removing bolts from a side panel while the electrolyzer 

is cooling); (2) fill the electrolyzer with an aqueous liquid; (3) allow the electrolyzer to cool before 

opening; and (4) schedule and staff maintenance of the electrolyzer to minimize the time the 

electrolyzer is open. 

c. When the electrolyzer top is raised and before moving the top and anodes, thoroughly flush all visible mercury from the top and the anodes with an aqueous liquid. 

d. While an electrolyzer is open, keep the bottom covered with an aqueous liquid or maintain a continuous flow of aqueous liquid. 

e. During an electrolyzer side panel change, take measures to ensure an aqueous liquid covers or 

flows over the bottom. 

f. Each time an electrolyzer is opened, inspect and replace components, as appropriate. 

Federal Register / Vol. 67, No. 128 / Wednesday, July 3, 2002 / Proposed Rules 44707

TABLE 1 TO SUBPART IIIII OF PART 63—WORK PRACTICE STANDARDS—DESIGN, OPERATION, AND MAINTENANCE

REQUIREMENTS—Continued

For . . . You must . . . 

g. If you step into an electrolyzer bottom, either remove all visible mercury from your footwear or replace them immediately after stepping out of the electrolyzer. 

h. If an electrolyzer is disassembled for overhaul maintenance or for any other reason, chemically 

clean the bed plate or thoroughly flush it with an aqueous liquid. 

i. Before transporting each electrolyzer part to another work area, remove all visible mercury from the 

part or contain the part to prevent mercury from dripping during transport. 

j. After completing maintenance on an electrolyzer, check any mercury piping flanges that were 

opened for liquid mercury leaks. 

k. If a liquid mercury spill occurs during any maintenance activity on an electrolyzer, clean it up in accordance with the requirements in Table 3 to this subpart. 

3. Vessels in liquid mercury service ........ If you replace a vessel containing mercury that is intended to trap and collect mercury after [DATE 

OF PUBLICATION OF THE FINAL RULE IN THE Federal Register], replace it with a vessel that 

has a cone shaped bottom with a drain valve or other design that readily facilitates mercury collection. 

4. Piping and process lines in liquid mercury service.a. Use piping with smooth interiors to avoid liquid mercury buildups within the pipe. 

b. To prevent mercury buildup after [DATE OF PUBLICATION OF THE FINAL RULE IN THE Federal 

Register], equip each new process line and piping system with adequate low point drains or mercury knock-out pots to facilitate mercury collection and recovery. 

5. Cell room floors ................................... a. Maintain a coating on cell room floors that is resistant to absorption of mercury and that facilitates 

the detection of liquid mercury spills or accumulations. 

b. Maintain cell room floors such that they are smooth and free of cracking and spalling. 

c. Maintain troughs and trenches to prevent mercury accumulation in the corners. 

d. Maintain a layer of aqueous liquid on liquid mercury contained in trenches or drains and replenish 

the aqueous layer at least once per day. 

e. Keep the cell room floor clean and free of debris. 

f. If you step into a liquid mercury spill or accumulation, either remove all visible mercury from your 

footwear or replace your footwear immediately. 

6. End boxes ........................................... a. Either equip each end box with a fixed cover that is leak tight, or route the end box head space to 

an end-box ventilation system. 

b. For each end-box ventilation system: (1) maintain a flow of aqueous liquid over the liquid mercury 

in the end box and maintain the temperature of the aqueous liquid below its boiling point, (2) maintain a negative pressure in the end-box ventilation system, and (3) maintain the end-box ventilation 

system in good condition. 

c. Maintain each end-box cover in good condition and keep the end box closed when the cell is in 

service and when liquid mercury is flowing down the cell, except when operation or maintenance 

activities require short- term access. 

d. Keep all bolts and C-clamps used to hold the covers in place when the cell is in service and when 

liquid mercury is flowing down the cell. 

e. Maintain each access port stopper in an end-box cover in good sealing condition and keep each 

end-box access port closed when the cell is in service and when liquid mercury is flowing down the 

cell. 

7. Decomposers ...................................... a. Maintain each decomposer cover in good condition and keep each decomposer closed and sealed, 

except when maintenance activities require the cover to be removed. 

b. Maintain leak-tight connections between the decomposer and the corresponding cell components, 

hydrogen system piping, and caustic system piping, except when maintenance activities require access to these connections. 

c. Keep each mercury cell amalgam seal pot closed and sealed, except when operation or maintenance activities require short-term access. 

d. Prior to opening a decomposer, do the following: (1) fill the decomposer with an aqueous liquid or 

drain the decomposer liquid mercury into a container that meets requirements listed below for 

closed containers, (2) allow the decomposer to cool before opening, and (3) complete work that 

can be done before opening the decomposer. 

e. Take precautions to avoid mercury spills when changing graphite grids or balls in horizontal 

decomposers or graphite packing in vertical decomposers. If a spill occurs, you must clean it up in 

accordance with the requirements in Table 3 to this subpart. 

f. After each maintenance activity, use an appropriate technique (see Table 7 to this subpart) to 

check for hydrogen leaks. 

g. Before transporting any internal part from the decomposer (such as the graphite basket) to another 

work area, remove all visible mercury from the part or contain the part to prevent mercury from 

dripping during transport. 

h. Store carbon from decomposers in accordance with the requirements in Table 5 to this subpart 

until the carbon is treated or is disposed. 

8. Submerged mercury pumps ................ a. Provide a vapor outlet connection from each submerged pump to an end-box ventilation system. 

The connection must be maintained under negative pressure. 

b. Keep each mercury pump tank closed, except when maintenance or operation activities require the 

cover to be removed. 

c. Maintain a flow of aqueous liquid over the liquid mercury in each mercury pump tank and maintain 

the aqueous liquid at a temperature below its boiling point. 

44708 Federal Register / Vol. 67, No. 128 / Wednesday, July 3, 2002 / Proposed Rules 

TABLE 1 TO SUBPART IIIII OF PART 63—WORK PRACTICE STANDARDS—DESIGN, OPERATION, AND MAINTENANCE

REQUIREMENTS—Continued

For . . . You must . . . 

9. Containers holding liquid mercury ....... Maintain a layer of aqueous liquid over liquid mercury containers in each open-top container. Replenish the aqueous layer holding liquid at least once per day and collect the liquid mercury mercury 

from the container in accordance with the requirements in Table 4 to this subpart. 

10. Containers used to store liquid mercury.a. Store liquid mercury in containers with tight fitting covers. 

b. Maintain the seals on the covers in good condition. 

c. Keep each container securely closed when mercury is not being added to, or removed from, the 

container. 

11. Caustic systems ................................ a. Maintain the seal between each caustic basket cover and caustic basket by using gaskets and 

other appropriate material. 

b. Prevent solids and liquids collected from back-flushing each primary caustic filter to contact floors 

or run into open trenches. 

c. Collect solids and liquids from back-flushing each primary caustic filter and store these mercurycontaining wastes in accordance with the requirements in Table 5 to this subpart. 

d. Keep each caustic basket closed and sealed, except when operation or maintenance activities require short term access. 

12. Hydrogen systems ............................. a. Collect drips from each hydrogen seal pot and compressor seal in containers meeting the requirements in this table for open containers. These drips should not be allowed to run on the floor or in 

open trenches. 

b. Minimize purging of hydrogen from a decomposer into the cell room by either sweeping the 

decomposer with an inert gas or by routing the hydrogen to the hydrogen system. 

c. Maintain hydrogen piping gaskets in good condition. 

d. After any maintenance activities, use an appropriate technique (see Table 7 to this subpart) to 

check all hydrogen piping flanges that were opened for hydrogen leaks. 

As stated in § 63.8192, you must meet the work practice standards in the following table:

TABLE 2 TO SUBPART IIIII OF PART 63.—WORK PRACTICE STANDARDS—REQUIRED INSPECTIONS

You must inspect . . . At least once 

each . . . And if you find . . . You must . . . 

1. Each vent hose on each mercury cell.12 hours ......... a leaking vent hose ........................................ take action immediately to correct the leak. 

2. Each open-top container 

holding liquid mercury.

12 hours ......... liquid mercury that is not covered by an 

aqueous liquid.

take action immediately to cover the liquid 

mercury with an aqueous liquid. 

3. Each end box ........................ 12 hours ......... a. an end-box cover not securely in place .... take action immediately to put the end-box 

cover securely in place. 

b. an end-box stopper not securely in place take action immediately to put the end-box 

stopper securely in place. 

c. liquid mercury in an end box that is not 

covered by an aqueous liquid at a temperature below boiling.

take action immediately to cover the liquid 

mercury with an aqueous liquid. 

4. Each mercury amalgam seal 

pot.

12 hours ......... a seal pot cover that is not securely in place take action immediately to put the seal pot 

cover securely in place. 

5. Each mercury seal pot .......... 12 hours ......... a mercury seal pot stopper not securely in 

place.

take action immediately to put the mercury 

seal pot stopper securely in place. 

6. Cell room floors ..................... month ............. cracks, spalling, or other deficiencies that 

could cause liquid mercury to become 

trapped.

repair the crack, spalling, or other deficiency 

within 1 month from the time you identify 

the deficiency. 

7. Pillars and beams .................. 6 months ........ cracks, spalling, or other deficiencies that 

could cause liquid mercury to become 

trapped.

repair the crack, spalling, or other deficiency 

within 1 month from the time you identify 

the deficiency. 

8. Each caustic basket .............. 12 hours ......... a caustic basket cover that is not securely in 

place.

take action immediately to put the caustic 

basket cover securely in place. 

9. All equipment and piping in 

the caustic system.

24 hours ......... equipment that is leaking caustic ................... initiate repair of the leaking equipment within 

72 hours from the time that you identify 

the caustic leak. 

10. All floors and other surfaces 

where liquid mercury could 

accumulate in cell rooms and 

other production facilities and 

in mercury recovery facilities.

12 hours ......... a liquid mercury spill or accumulation ........... take the required action specified in Table 3 

to this subpart. 

Federal Register / Vol. 67, No. 128 / Wednesday, July 3, 2002 / Proposed Rules 44709

TABLE 2 TO SUBPART IIIII OF PART 63.—WORK PRACTICE STANDARDS—REQUIRED INSPECTIONS—Continued

You must inspect . . . At least once 

each . . . And if you find . . . You must . . . 

11. Each electrolyzer bottom, 

electrolyzer side panel, end 

box, mercury amalgam seal 

pot, decomposer, mercury 

pump, and hydrogen cooler, 

and all other vessels, piping, 

and equipment in liquid mercury service in the cell room.

24 hours ......... equipment that is leaking liquid mercury ....... take the required action specified in Table 3 

to this subpart. 

12. Each decomposer and all 

hydrogen piping up to the hydrogen header.

12 hours ......... equipment that is leaking hydrogen and/or 

mercury vapor.

take the required action specified in Table 3 

to this subpart. 

13. All equipment in the hydrogen system from the start of 

the header to the last control 

device.

3 months ........ equipment that is leaking hydrogen and/or 

mercury vapor.

take the required action specified in Table 3 

to this subpart. 

NOTE: See Table 7 of this subpart for examples of techniques for conducting the inspections required in this table. 

As stated in § 63.8192, you must meet the work practice standards in the following table:

TABLE 3 TO SUBPART IIIII OF PART 63.—WORK PRACTICE STANDARDS—REQUIRED ACTIONS FOR LIQUID MERCURY

SPILLS AND ACCUMULATIONS AND HYDROGEN AND MERCURY VAPOR LEAKS

During a required inspection or at any 

other time, if you find . . . You must . . . 

1. A liquid mercury spill or accumulation a. Initiate clean up of the liquid mercury spill or accumulation as soon as possible, but no later than 1 

hour from the time you detect it. 

b. Clean up liquid mercury using: (1) a mercury vacuum cleaner, (2) by washing the mercury to the 

nearest trench or sump, or (3) by using an alternative method. If you use an alternative method to 

clean up liquid mercury, you must submit a description of the method to the Administrator in your 

Notification of Compliance Status report. 

c. If you use a mercury vacuum cleaner: (1) the vacuum cleaner must be designed to prevent generation of airborne mercury, (2) you must cap the ends of hoses after each use, and (3) after 

vacuuming, you must wash down the area. 

d. Inspect all equipment in liquid mercury service in the surrounding area to identify the source of the 

liquid mercury within 1 hour from the time you detect the liquid mercury spill or accumulation. 

e. If you identify leaking equipment as the source of the spill or accumulation, contain the dripping 

mercury, stop the leak, and repair the leaking equipment as specified below. 

f. If you cannot identify the source of the liquid mercury spill or accumulation, re-inspect the area 

within 6 hours of the time you detected the liquid mercury spill or accumulation, or within 6 hours of 

the last inspection of the area. 

2. Equipment that is leaking liquid mercury.a. Contain the liquid mercury dripping from the leaking equipment by placing a container under the 

leak within 30 minutes from the time you identify the liquid mercury leak. 

b. The container must meet the requirement for open-top containers in Table 1 to this subpart. 

c. Make a first attempt at stopping the leak within 1 hour from the time you identify the liquid mercury 

leak. 

d. Stop the leak and repair the leaking equipment within 4 hours from the time you identify the liquid 

mercury leak. 

e. You can delay repair of equipment leaking liquid mercury if you either: (1) isolate the leaking 

equipment from the process so that it does not remain in mercury service; or (2) determine that 

you cannot repair the leaking equipment without taking the cell off line, provided that you contain 

the dripping mercury at all times as described above, and take the cell off line as soon as practicable, but no later than 48 hours from the time you identify the leaking equipment. You cannot 

place the cell back into service until the leaking equipment is repaired. 

3. A decomposer or hydrogen system 

piping up to the hydrogen header that 

is leaking hydrogen and/or mercury 

vapor.

a. Make a first attempt at stopping the leak within 1 hour from the time you identify the hydrogen and/

or mercury vapor leak. 

b. Stop the leak and repair the leaking equipment within 4 hours from the time you identify the hydrogen and/or mercury vapor leak. 

c. You can delay repair of equipment leaking hydrogen and/or mercury vapor if you isolate the leaking equipment or take the cell off line until you repair the leaking equipment. 

4. Equipment in the hydrogen system, 

from the start of the hydrogen header 

to the last control device, that is leaking hydrogen and/or mercury vapor.

a. Make a first attempt at stopping the leak within 4 hours from the time you identify the hydrogen 

and/or mercury vapor leak. 

b. Stop the leak and repair the header within 24 hours from the time you identify the hydrogen and/or 

mercury vapor leak. 

44710 Federal Register / Vol. 67, No. 128 / Wednesday, July 3, 2002 / Proposed Rules 

TABLE 3 TO SUBPART IIIII OF PART 63.—WORK PRACTICE STANDARDS—REQUIRED ACTIONS FOR LIQUID MERCURY

SPILLS AND ACCUMULATIONS AND HYDROGEN AND MERCURY VAPOR LEAKS—Continued

During a required inspection or at any 

other time, if you find . . . You must . . . 

c. You can delay repair of equipment leaking hydrogen and/or mercury vapor if you isolate the leaking equipment. 

As stated in § 63.8192, you must meet the work practice standards in the following table:

TABLE 4 TO SUBPART IIIII OF PART 63.—WORK PRACTICE STANDARDS—REQUIREMENTS FOR MERCURY LIQUID

COLLECTION

You must collect liquid 

mercury from . . . When 

Additional requirements 

1. Open-top containers ...... a. at least once each 72 

hours.

i. If you spill liquid mercury 

during collection or 

transport, you must take 

the action specified in 

Table 3 to this subpart 

for liquid mercury spills 

and accumulations.

(1) From the time that you 

collect liquid mercury 

into a temporary container until the time that 

you store the liquid mercury, you must keep it 

covered by an aqueous 

liquid.

(A) Within 4 hours from 

the time you collect the 

liquid mercury, you must 

transfer it from each 

temporary container to a 

storage container that 

meets the specifications 

in Table 1 to this subpart. 

2. Vessels, low point 

drains, mercury knockout pots, and other 

closed mercury collection points.

a. at least once each week See 1.a.i. above ................ See 1.a.i.(1) above ........... See 1.a.i.(A) above. 

3. All other equipment ....... a. whenever maintenance 

activities require the 

opening of the equipment.

See 1.a.i. above ................ See 1.a.i.(1) above ........... See 1.a.i.(A) above. 

As stated in § 63.8192, you must meet the work practice standards in the following table:

TABLE 5 TO SUBPART IIIII OF PART 63.—WORK PRACTICE STANDARDS—REQUIREMENTS FOR HANDLING AND STORAGE

OF MERCURY-CONTAINING WASTES

For . . . You must . . . 

1. Carbon media from decomposers and 

cell room sludges.

a. Store wastes in closed containers, or 

b. Maintain a layer of aqueous liquid over wastes in open-top containers and replenish the aqueous 

layer at least once per week. 

2. All other mercury-containing wastes ... a. Wash or chemically decontaminate wastes to remove visible mercury, or 

b. Store wastes in closed containers. 

As stated in § 63.8192, your written washdown plan must address the elements contained in the following table:

TABLE 6 TO SUBPART IIIII OF PART 63.—REQUIRED ELEMENTS OF WASHDOWN PLANS

For each of the following areas . . . You must establish the following as part of your plan . . . 

1. Center aisles of cell rooms .................................................................. A description of the manner of washdown of the area, and the 

washdown frequency for the area. 

2. Electrolyzers. 

3. End boxes and areas under end boxes. 

4. Decomposers and areas under decomposers. 

5. Caustic baskets and areas around caustic baskets. 

6. Hydrogen system piping. 

7. Basement floor of cell rooms. 

8. Tanks. 

9. Pillars and beams in cell rooms. 

10. Mercury cell repair areas. 

11. Maintenance shop areas. 

12. Work tables. 

13. Castings. 

14. Storage areas for mercury-containing wastes. 

Federal Register / Vol. 67, No. 128 / Wednesday, July 3, 2002 / Proposed Rules 44711

As stated in Tables 1 and 2 of Subpart IIIII, examples of techniques for equipment problem identification, leak 

detection and mercury vapor measurements can be found in the following table:

TABLE 7 TO SUBPART IIIII OF PART 63.—EXAMPLES OF TECHNIQUES FOR EQUIPMENT PROBLEM IDENTIFICATION, LEAK

DETECTION AND MERCURY VAPOR MEASUREMENTS

To Detect . . . You could use . . . Principle of detection . . . 

1. Leaking vent hoses; liquid mercury 

that is not covered by an aqueous liquid in open-top containers or end 

boxes; end-box covers or stoppers, 

amalgam seal pot stoppers, or caustic 

basket covers not securely in place; 

cracks or spalling in cell room floors, 

pillars, or beams; caustic leaks; liquid 

mercury accumulations or spills; and 

equipment that is leaking liquid mercury.

Visual inspections. 

2. Equipment that is leaking hydrogen 

and/or mercury vapor during required 

by Table 2 to inspections. this subpart.

a. Auditory and visual inspections. 

b. Portable mercury vapor analyzer—

ultraviolet light absorption detector..

A sample of gas is drawn through a detection cell where 

ultraviolet light at 253.7 nanometers (nm) is directed perpendicularly through the sample toward a photodetector. 

Mercury absorbs the incident light in proportion to its 

concentration in the air stream. 

c. Portable mercury vapor analyzer—

gold film amalgamation detector..

A sample of gas is drawn through a detection cell containing a gold film detector. Mercury amalgamates with 

the gold film, changing the resistance of the detector in 

proportion to the mercury concentration in the air sample. 

d. Portable short-wave ultraviolent light, 

fluorescent background—visual indication..

Ultraviolet light is directed toward a fluorescent background 

positioned behind a suspected source of mercury emissions. Mercury vapor absorbs the ultraviolet light, projecting a dark shadow image on the fluorescent background. 

e. Portable combustible gas meter. 

3. Level of mercury vapor in the cell 

room and other areas.

a. Portable mercury vapor analyzer—

ultraviolet light absorption detector.

A sample of gas is drawn through a detection cell where 

ultraviolet light at 253.7 nanometers (nm) is directed perpendicularly through the sample toward a photodetector. 

Mercury absorbs the incident light in proportion to its 

concentration in the air stream. 

b. Portable mercury vapor analyzer—

gold film amalgamation detector.

A sample of gas is drawn through a detection cell containing a gold film detector. Mercury amalgamates with 

the gold film, changing the resistance of the detector in 

proportion to the mercury concentration in the air sample. 

c. Permanganate impingement A known volume of gas sample is absorbed in potassium 

permanganate solution. Mercury in the solution is determined using a cold vapor adsorption analyzer, and the 

concentration of mercury in the gas sample is calculated. 

As stated in § 63.8256(c), you must keep the records (related to the work practice standards) specified in the following 

table:

TABLE 8 TO SUBPART IIIII OF PART 63.—REQUIRED RECORDS FOR WORK PRACTICE STANDARDS

For each . . . You must record the following information . . . 

1. Inspection required by Table 2 to this subpart .................................... Date and time the inspection was conducted. 

2. Of the following situations found during an inspection required by 

Table 2 to this subpart: leaking of vent hose; open-top container 

where liquid mercury is not covered by an aqueous liquid; end-box 

cover that is not securely in place; end-box stopper that is not securely in place; end box where liquid mercury is not covered by an 

aqueous liquid at a temperature below boiling; seal pot cover that is 

not securely in place; open or mercury seal pot stopper that is not 

securely in place; crack, spalling, or other deficiency in a cell room 

floor, pillar, or beam that could cause liquid mercury to become 

trapped; or caustic basket that is not securely in place. 

a. Description the condition. 

b. Location of the condition. 

c. Date and time you identify the condition. 

d. Description of the corrective action taken. 

e. Date and time you successfully complete the corrective action. 

3. A caustic leak during an inspection required by Table 2 to this subpart. a. Location of the leak. 

b. Date and time you identify the leak. 

44712 Federal Register / Vol. 67, No. 128 / Wednesday, July 3, 2002 / Proposed Rules 

TABLE 8 TO SUBPART IIIII OF PART 63.—REQUIRED RECORDS FOR WORK PRACTICE STANDARDS—Continued

For each . . . You must record the following information . . . 

c. Date and time you successfully stop the leak and repair the leaking 

equipment. 

4. Liquid mercury spill or accumulation identified during an inspection 

required by Table 2 to this subpart or at any other time.

a. Location of the liquid mercury spill or accumulation. 

b. Estimate of the weight of liquid mercury. 

c. Date and time you detect the liquid mercury spill or accumulation. 

d. Method you use to clean up the liquid mercury spill or accumulation. 

e. Date and time when you clean up the liquid mercury spill or accumulation. 

f. Source of the liquid mercury spill or accumulation. 

g. If the source of the liquid mercury spill or accumulation is not identified, the time when you reinspect the area. 

5. Liquid mercury leak or hydrogen leak identified during an inspection 

required by Table 2 to this subpart or at any other time. 

a. Location of the leak. 

b. Date and time you identify the leak. 

c. If the leak is a liquid mercury leak, the date and time that you successfully contain the dripping liquid mercury. 

d. Date and time you first attempt to stop the leak. 

e. Date and time you successfully stop the leak and repair the leaking 

equipment. 

f. If you take a cell off line or isolate the leaking equipment, the date 

and time you take the cell off line or isolate the leaking equipment, 

and the date and time you put the cell or isolated equipment back 

into service. 

6. Carbon media from decomposers and cell room sludges. .................. a. A statement that these wastes are stored in closed containers, or 

b. Date and time you replenish the aqueous layer over these wastes 

stored in open-top containers. 

7. All other mercury-containing wastes .................................................... a. A description of how you remove visible mercury, or 

b. A statement that these wastes are stored in closed containers. 

As stated in § 63.8262, you must comply with the applicable General Provisions requirements according to the 

following table:

TABLE 9 TO SUBPART IIIII OF PART 63.—APPLICABILITY OF GENERAL PROVISIONS TO SUBPART IIIII 

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) ............................... Compliance with Standards and Maintenance Requirements.Yes.

§ 63.6(h) .................................................. Compliance with Opacity and Visible 

Emission Standards.

No ......................... Subpart IIIII does not have opacity and 

visible emission standards. 

§ 63.7 ...................................................... Performance Testing Requirements .... Yes. ....................... Subpart IIIII specifies additional requirements related to site-specific 

test plans and the conduct of performance tests. 

§ 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 site-specific 

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), (g)–(j) ............................... Notification Requirements .................... Yes.

§ 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)(i)–(xii), (xiv); 

(b)(3); (c); (d)(1)–(2), (4)–(5); (e); (f).

Recordkeeping/Reporting ..................... Yes.

§ 63.10(b)(2) (xiii) ................................... CMS Records for RATA Alternative ..... No ......................... Subpart IIIII does not require CEMS. 

Federal Register / Vol. 67, No. 128 / Wednesday, July 3, 2002 / Proposed Rules 44713

TABLE 9 TO SUBPART IIIII OF PART 63.—APPLICABILITY OF GENERAL PROVISIONS TO SUBPART IIIII—Continued

Citation Subject Applies to Subpart 

IIIII Explanation 

§ 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.

[FR Doc. 02–15873 Filed 7–2–02; 8:45 am] 

BILLING CODE 6560–50–P

ENVIRONMENTAL PROTECTION 

AGENCY 

40 CFR Part 63 

[FRL–7229–6] 

National Emission Standards for 

Hazardous Air Pollutants: Chlorine and 

Hydrochloric Acid Emissions From 

Chlorine Production

AGENCY: Environmental Protection 

Agency (EPA).

ACTION: Proposed decision not to 

regulate. 

SUMMARY: EPA proposes not to regulate 

chlorine and hydrochloric acid (HCl) 

emissions for the Chlorine Production 

source category. We have determined 

that no further control is necessary 

because chlorine and HCl have welldefined health thresholds, and chlorine 

and HCl air emissions from chlorine 

producers result in human exposures in 

the ambient air that are below the 

threshold values with an ample margin 

of safety. This notice does not address 

mercury emissions from mercury cell 

chlor-alkali plants. Those emissions are 

addressed in a separate action in the 

proposed rule section of this Federal 

Register.

DATES: Comments. Submit comments on 

or before September 3, 2002. 

Public Hearing. If anyone contacts the 

EPA requesting to speak at a public 

hearing by July 23, 2002, a public 

hearing will be held on August 2, 2002.

ADDRESSES: Comments. By U.S. Postal 

Service, send comments (in duplicate if 

possible) to: Air and Radiation Docket 

and Information Center (6102), 

Attention Docket Number A–2002–09, 

U.S. EPA, 1200 Pennsylvania Avenue, 

NW, Washington, DC 20460. In person 

or by courier, deliver comments (in 

duplicate if possible) to: Air and 

Radiation Docket and Information 

Center (6102), Attention Docket Number 

A–2002–09, U.S. EPA, 401 M Street, 

SW., Washington, DC 20460. 

Public Hearing. If a public hearing is 

held, it will be held at the new EPA 

facility complex in Research Triangle 

Park, North Carolina. 

Docket. Docket No.

A–2002–09 contains supporting 

information used in developing the 

notice of proposed action for the 

Chlorine Production source category. 

The docket is located at the U.S. EPA, 

401 M Street, SW., Washington, DC 

20460 in Room M–1500, Waterside Mall 

(ground floor), and may be inspected 

from 8:30 a.m. to 5:30 p.m., Monday 

through Friday, excluding legal 

holidays.

FOR FURTHER INFORMATION CONTACT: Mr. 

Iliam Rosario, Metals Group, Emission 

Standards Division (C439–02), U.S. 

EPA, Research Triangle Park, North 

Carolina 27711, telephone number: 

(919) 541–5308, facsimile: (919) 541–

5600, electronic mail address: 

rosario.iliam@epa.gov.

SUPPLEMENTARY INFORMATION:

Comments. Comments and data may be 

submitted by electronic mail (e-mail) to: 

a-and-r-docket@epa.gov. Electronic 

comments must be submitted as an 

ASCII file to avoid the use of special 

characters and encryption problems and 

will also be accepted on disks in 

WordPerfect format. All comments and 

data submitted in electronic form must 

note the docket number: Docket No. A–

2002–09. No confidential business 

information (CBI) should be submitted 

by e-mail. Electronic comments may be 

filed online at many Federal Depository 

Libraries. 

Commenters wishing to submit 

proprietary information for 

consideration must clearly distinguish 

such information from other comments 

and clearly label it as CBI. Send 

submissions containing such 

proprietary information directly to the 

following address, and not to the public 

docket, to ensure that proprietary 

information is not inadvertently placed 

in the docket: OAQPS Document 

Control Office (C404–02), Attention: 

Iliam Rosario, Metals Group, Emission 

Standards Division, U.S. EPA, Research 

Triangle Park, NC 27711. The EPA will 

disclose information identified as CBI 

only to the extent allowed by the 

procedures set forth in 40 CFR part 2. 

If no claim of confidentiality 

accompanies a submission when it is 

received by the EPA, the information 

may be made available to the public 

without further notice to the 

commenter. 

Public Hearing. Persons interested in 

presenting oral testimony or inquiring 

as to whether a hearing is to be held 

should contact Cassie Posey, telephone 

number: (919) 541–0069. Persons 

interested in attending the public 

hearing must also call Cassie Posey to 

verify the time, date, and location of the 

hearing. The public hearing will provide 

interested parties the opportunity to 

present data, views, or arguments 

concerning the proposed emission 

standards. 

Docket. The docket is an organized 

and complete file of all the information 

considered by the EPA in rule 

development. The docket is a dynamic 

file because material is added 

throughout the rulemaking process. The 

docketing system is intended to allow 

members of the public and industries 

involved to readily identify and locate 

documents so that they can effectively 

participate in the rulemaking process. 

Along with the proposed and 

promulgated standards and their 

preambles, the contents of the docket 

will serve as the record in the case of 

judicial review. (See section 307(d) 

(7)(A) of the Clean Air Act (CAA).) The 

materials related to this notice of 

proposed action are available for review 

in the docket or copies may be mailed 

on request from the Air Docket by 

calling (202) 260–7548. A reasonable fee 

may be charged for copying docket 

materials. 

WorldWide Web (www) Information.

In addition to being available in the 

docket, an electronic copy of today’s 

notice of proposed action will also be 

available through EPA’s www site. 

Following signature, a copy of the rule 

will be posted on our policy and