[Federal Register Volume 68, Number 244 (Friday, December 19, 2003)]
[Rules and Regulations]
[Pages 70948-70957]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 03-22929]



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Part III





Environmental Protection Agency





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40 CFR Part 63



National Emission Standards for Hazardous Air Pollutants: Chlorine and 
Hydrochloric Acid Emissions from Chlorine Production; Final Rule

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

[[Page 70948]]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 63

[OAR-2002-0016, FRL-7554-6]
RIN 2060-AK38


National Emission Standards for Hazardous Air Pollutants: 
Chlorine and Hydrochloric Acid Emissions From Chlorine Production

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final decision to delete subcategory.

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SUMMARY: This final action deletes the subcategory of sources that do 
not utilize mercury cells to produce chlorine and caustic. We have 
determined that this non-mercury cell chlorine production subcategory 
should be deleted because chlorine and hydrochloric acid (HCl), the 
only hazardous air pollutants (HAP) emitted, are not carcinogenic, have 
well-defined health thresholds, and chlorine and HCl air emissions from 
each non-mercury cell chlorine subcategory source do not exceed a level 
which is adequate to protect public health with an ample margin of 
safety. In addition, the emissions of chlorine and HCl will not result 
in any adverse environmental effects. This final action does not 
address chlorine and HCl emissions from mercury cell chlor-alkali 
plants. The final rulemaking for the mercury cell chlor-alkali plant 
subcategory is contained elsewhere in this issue of the Federal 
Register.

EFFECTIVE DATE: December 19, 2003.

ADDRESSES: Docket. We have established an official public docket for 
this action under Docket ID No. OAR-2002-0016, A-2002-09, A-2000-32, 
and OAR-2002-0017 available for public viewing at the Office of Air and 
Radiation Docket and Information Center (Air Docket) in the EPA Docket 
Center, (EPA/DC) EPA West, Room B102, 1301 Constitution Avenue, NW, 
Washington, DC. Docket No. A-2002-09 or OAR-2002-0016 contains 
supporting information used in developing the proposed and final action 
for the non-mercury cell subcategory of the chlorine production source 
category addressed in this action. The docket is available for public 
viewing at the Office of Air and Radiation Docket and Information 
Center (Air Docket) in the EPA Docket Center, (EPA/DC) EPA West, Room 
B102, 1301 Constitution Avenue, NW, Washington, DC and may be inspected 
from 8:30 a.m. to 4:30 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: 
[email protected].

SUPPLEMENTARY INFORMATION:
    Docket. The official public docket consists of the documents 
specifically referenced in this final action, any public comments 
received, and other information related to this final action. Although 
a part of the official docket, the public docket does not include 
Confidential Business Information or other information whose disclosure 
is restricted by statute. The official public docket is the collection 
of materials that is available for public viewing. The EPA Docket 
Center Public Reading Room is open from 8:30 a.m. to 4:30 p.m., Monday 
through Friday, excluding legal holidays. The telephone number for the 
Reading Room is (202) 566-1744, and the telephone number for the Air 
Docket is (202) 566-1742.
    Electronic Docket Access. You may access this final action 
electronically through the EPA Internet under the ``Federal Register'' 
listings at http://www.epa.gov/fedrgstr/.
    An electronic version of the public docket is available through 
EPA's electronic public docket and comment system, EPA Dockets. You may 
use EPA Dockets at http://www.epa.gov/edocket/ to view public comments, 
access the index listing of the contents of the official public docket, 
and to access those documents in the public docket that are available 
electronically. Although not all docket materials may be available 
electronically, you may still access any of the publicly available 
docket materials through the docket facility in the above paragraph 
entitled ``Docket.'' Once in the system, select ``search,'' then key in 
the appropriate docket identification number.
    Judicial Review. Under CAA section 307(b), judicial review of the 
final action is available only by filing a petition for review in the 
U.S. Court of Appeals for the District of Columbia Circuit on or before 
February 17, 2004. Only those objections to the final action which were 
raised with reasonable specificity during the period for public comment 
may be raised during judicial review.
    Affected entities. Entities potentially affected by this action 
include facilities engaged in the production of chlorine using non-
mercury cells, for example, diaphragm cells and membrane cells. 
Affected 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 affected 
by this final action. If you have questions regarding the applicability 
of this final action to a particular entity, consult the person listed 
in the preceding FOR FURTHER INFORMATION CONTACT section.
    World Wide Web Information. In addition to being available in the 
docket, an electronic copy of today's final action will also be 
available through EPA's World Wide Web site. Following signature, a 
copy of this final action 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.
    Outline. The information presented in this preamble is organized as 
follows:

I. Background
    A. What Is the Source of Authority for This Final Action?
    B. What Is the Source Category?
    C. How Did the Public Participate in Developing This Final 
Action?
II. Summary of Final Action
III. Summary of Major Comments
    A. What Issues Were Raised Regarding the Statutory Authority for 
This Final Action?
    B. What Issues Were Raised Related to the Potential Overlap With 
the HCl Production NESHAP?
    C. What Issues Were Raised Regarding the Risk Assessment That 
Forms the Technical Basis for This Final Action?
IV. Statutory and Executive Order Reviews
    A. Executive Order 12866: Regulatory Planning and Review
    B. Paperwork Reduction Act
    C. Regulatory Flexibility Act
    D. Unfunded Mandates Reform Act
    E. Executive Order 13132: Federalism
    F. Executive Order 13175: Consultation and Coordination With 
Indian Tribal Governments
    G. Executive Order 13045: Protection of Children From 
Environmental Health and Safety Risks
    H. Executive Order 13211: Actions That Significantly Affect 
Energy Supply, Distribution, or Use
    I. National Technology Transfer Advancement Act
    J. Congressional Review Act


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I. Background

A. What Are the Sources of Authority for This Final Action?

    Section 112 of the Clean Air Act (CAA) contains our authorities for 
reducing emissions of HAP. Section 112(c)(1) of the CAA requires us to 
list categories and subcategories of major sources and area sources of 
HAP and to establish national emission standards for hazardous air 
pollutants (NESHAP) for the listed source categories and subcategories. 
Section 112(c)(9) of the CAA contains provisions that allow the 
deletion of source categories listed under CAA section 112(c)(1) 
provided that certain conditions are met. For chemicals that may result 
in cancer in humans, the condition is that no source in the category 
emit HAP in quantities that result in a lifetime cancer risk of greater 
than one in a million to the individual in the population who is most 
exposed. For chemicals that result in adverse health effects other than 
cancer or adverse environmental effects, the conditions are that no 
source in the category emit HAP that exceed a level ``adequate to 
protect public health with an ample margin of safety'' and that no 
source emit HAP in quantities to cause adverse environmental effects.
    Section 112(d) of the CAA requires us to promulgate regulations 
establishing emission standards for each category or subcategory of 
major sources and area sources of HAP listed pursuant to CAA section 
112(c). Section 112(d)(2) of the CAA specifies that emission standards 
promulgated under the section shall require the maximum degree of 
reductions in emissions of the HAP subject to CAA section 112 that are 
deemed achievable considering cost and any non-air quality health and 
environmental impacts and energy requirements.
    Each of the 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).
    The CAA includes exceptions to the general statutory requirement to 
establish emission standards based on MACT. For pollutants for which a 
threshold has been established, CAA section 112(d)(4) allows us ``. . . 
to consider such threshold level, with an ample margin of safety, when 
establishing emissions standards. . . .''

B. What Is the Source Category?

    The chlorine production source category was initially listed as a 
category of major sources of HAP pursuant to section 112(c)(1) of the 
CAA on July 16, 1992 (57 FR 31576). At the time of the initial listing, 
we defined the chlorine production source category as follows: ``The 
Chlorine Production Source Category includes any facility engaged in 
the production of chlorine. The category includes, but is not limited 
to, facilities producing chlorine by the following production methods: 
diaphragm cell, mercury cell, membrane cell, hybrid fuel cell, Downs 
cell, potash manufacture, hydrochloric acid decomposition, nitrosyl 
chloride process, nitric acid/salt process, Kel-Chlor process, and 
sodium chloride/sulfuric acid process.''
    In our subsequent analysis of the chlorine production source 
category, we did not identify any facilities that produce chlorine 
using hybrid fuel cells, the nitrosyl chloride process, the Kel-Chlor 
process, the sodium chloride/sulfuric acid process, or as a by-product 
from potash manufacturing. The majority of the source category is made 
up of chlor-alkali plants that produce chlorine and caustic (sodium 
hydroxide) using mercury cells, diaphragm cells, or membrane cells. We 
also identified operating plants that produce chlorine as a by-product: 
one from the production of sodium metal in Down cells, another from the 
production of potassium nitrate fertilizer that uses the nitric acid/
salt process, and a third that produces chlorine as a by-product from 
primary magnesium refining (magnesium refining is a separately listed 
source category, and is being addressed on its own in a separate 
rulemaking). In addition, at a site where a membrane cell process is 
located, we have identified a process that produces chlorine through 
the decomposition of HCl. Our analysis shows that the only HAP emitted 
from sources within the chlorine production source category are 
chlorine, HCl, and mercury, and mercury is only emitted from mercury 
cell chlor-alkali plants.
    Because of the differences in the production methods and the HAP 
emitted, we decided to divide the chlorine production category into two 
subcategories: (1) Mercury cell chlor-alkali plants, and (2) chlorine 
production plants that do not rely upon mercury cells for chlorine 
production (diaphragm cell chlor-alkali plants, membrane cell chlor-
alkali plants, etc). Thus, on July 3, 2002, we issued different 
proposals to address the emissions of mercury from the mercury cell 
chlorine production subcategory sources (67 FR 44672) and the emissions 
of chlorine and HCl from both the non-mercury cell chlorine production 
subcategory and the mercury cell chlorine production subcategory 
sources (67 FR 44713). This final action deletes the non-mercury cell 
chlorine production subcategory. Elsewhere in today's Federal Register, 
we are issuing a final rulemaking to regulate mercury emissions for 
mercury cell chlorine production subcategory sources to regulate 
mercury emissions, and we are utilizing our authority under CAA section 
112(d)(4) not to regulate chlorine and HCl emissions from the mercury 
cell chlorine production source category.
    In the non-mercury cell chlorine production subcategory, we 
identified 20 major source plant sites where diaphragm or membrane cell 
chlor-alkali chlorine production plants are located. None of the non-
mercury cell chlorine production processes at these sites emit HAP 
greater than 10 tons per year (tpy) of one HAP or 25 tpy of all HAP 
(that is, they would not be major source if they were not collocated 
with other HAP emission sources), but the total emissions from the 
entire contiguous plant site make each a major source.

C. How Did the Public Participate in Developing This Final Action?

    Prior to proposal, we met with industry representatives to discuss 
the data and information used to develop the proposed action. In 
addition, these and other potential stakeholders, including equipment 
vendors and environmental groups, had opportunity to comment on the 
proposed action.
    The proposed action was published in the Federal Register on July 
3, 2002 (67 FR 44713). The preamble to the proposed action discussed 
the availability of technical support documents, which described in 
detail the information gathered during the standards development 
process. Public comments were solicited at proposal.
    We received eight public comment letters on the proposed action. 
The commenters represent the following affiliations: industry 
representatives, governmental entities, and environmental groups during 
the public comment. In the post-proposal period, we had discussions 
with commenters and other stakeholders to clarify comments and to 
assist in our analysis of the comments. Records of these contacts are 
found in Docket No. A-2002-09 or OAR-2002-0016.

II. Summary of Final Action

    This final action deletes the subcategory of the Chlorine 
Production Source Category for facilities that do not utilize mercury 
cells to produce chlorine and caustic. This action is

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being made under our authority in CAA section 112(c)(9)(B)(ii). This 
final action does not impact the other subcategory of the Chlorine 
Production Source Category: Mercury Cell Chlor-Alkali Plants. A final 
rulemaking addressing the Mercury Cell Chlor-alkali Plant subcategory 
is contained in a separate section of today's Federal Register.

III. Summary of Major Comments

    On July 3, 2002 (67 FR 44713), we proposed not to regulate chlorine 
and HCl emissions from all chlorine production processes (mercury and 
non-mercury cell) under the authority of CAA section 112(d)(4). We 
based that decision on our determination that no further control is 
necessary because chlorine and HCl are health threshold pollutants, and 
chlorine and HCl levels emitted from chlorine production processes are 
below their threshold values within an ample margin of safety, and they 
do not result in adverse environmental effects.
    For a complete summary of all the comments received on the proposed 
rule and our responses to them, refer to the ``National Standards for 
Hazardous Air Pollutants: Chlorine and Hydrochloric Acid Emissions from 
Chlorine Production: Summary of Public Comments and Responses'' in 
Docket No. A-2002-09 or OAR-2002-0016.

A. What Issues Were Raised Regarding the Statutory Authority for This 
Final Action?

    Comment: Several comments were received related to our decision not 
to regulate chlorine and HCl emissions from chlorine production under 
the authority of CAA section 112(d)(4). Some commenters supported that 
decision and believed the interpretation of our authority under CAA 
section 112(d)(4) was appropriate. In contrast, other commenters 
disagreed with EPA's interpretation of CAA section 112(d)(4). Some of 
the commenters believed that EPA should use its authority under CAA 
section 112(c)(9)(B)(ii).
    Several commenters supported the decision not to regulate chlorine 
and HCl emissions from chlorine production plants under the authority 
of CAA section 112(d)(4). One commenter stated that EPA conducted an 
appropriate analysis to determine that human exposures from ambient 
concentrations are well below threshold values with an ample margin of 
safety. According to another commenter, any further regulation of 
chlorine and HCl emissions from the chlorine production industry would 
have no environmental benefits, but would result in costs for 
monitoring, recordkeeping, and reporting efforts to certify compliance 
with any requirements. The commenter was concerned that a rulemaking 
would also stretch EPA's limited resources in monitoring for 
compliance. Three commenters stated that EPA's interpretation of their 
authority under CAA section 112(d)(4) was supported by the legislative 
history, which emphasizes that Congress included section 112(d)(4) in 
the CAA to prevent unnecessary regulation of source categories. The 
commenter agreed that under CAA section 112(d)(4), once EPA establishes 
that a pollutant has a health threshold and that exposure to that 
pollutant's emissions are below the health threshold, EPA should 
refrain from setting MACT standards for that pollutant. The commenter 
further suggested that EPA should use CAA section 112(d)(4) whenever 
setting emission standards under CAA section 112(d).
    Three commenters disagreed with EPA's interpretation of CAA section 
112(d)(4). They did not believe that CAA section 112(d)(4) could be 
used as an alternative to setting MACT standards under CAA section 
112(d)(3). One commenter noted that the phrase ``in lieu of'' was not 
included in the CAA section 112(d)(4) provisions, and that its absence 
was intentional. In support of their claim, the commenter pointed to 
CAA section 112(d)(5), which does contain the phrase ``in lieu of.'' 
The commenter interpreted CAA section 112(d)(4) to mean that health 
based thresholds can be considered when establishing the degree of MACT 
requirements, but not in place of the requirement to establish a MACT 
floor pursuant to CAA section 112(d)(3).
    The commenter also pointed to the provisions of CAA section 
112(c)(2) which require the Administrator to establish NESHAP for 
listed source categories and subcategories. The commenter was concerned 
that EPA evaluated emissions from chlorine production plants and 
concluded that since they do not pose a threat to human health and the 
environment, the Administrator is relieved of her responsibilities to 
establish a MACT standard. The commenter maintained that this position 
is not supported by CAA section 112(c)(2).
    The commenter also referred to CAA section 112(d)(1) which states 
``. . . the Administrator shall promulgate regulations establishing 
emission standards for each category or subcategory of major sources 
and area sources of hazardous air pollutants listed for regulation 
pursuant to subsection (c) of this section. . . .'' Thus, the commenter 
stated that EPA did not have the authority to ``make a determination of 
no regulation for a listed source category or pollutant.''
    Finally, the commenter referred to CAA section 112(d)(3), which 
contains the MACT floor provisions. According to the commenter, the 
intent of the NESHAP program is to develop a MACT floor, and EPA is not 
fulfilling the requirements of the CAA by not performing such an 
analysis. The commenter stated that a majority of facilities identified 
in the analysis have adequate controls due to State regulations and 
these controls should be incorporated into the MACT floor evaluation. 
The commenter was particularly concerned that by not developing a MACT 
floor, no new source MACT standards were created. The commenter 
requested that EPA perform a MACT floor analysis, and develop a NESHAP 
for new sources.
    Two commenters that stated that they believe that EPA should 
support their decision not to regulate the chlorine production source 
category by citing the provisions of CAA section 112(c)(9)(B)(ii) in 
addition to the provisions of CAA section 112(d)(4). The commenters 
stated that the evaluation performed by EPA would also be sufficient 
for deleting sources under CAA section 112(c)(9)(B)(ii), and that EPA's 
proposal to not regulate chlorine production is similar to deleting a 
subcategory of the chlorine production source category (i.e., all 
chlorine production sources other than those using the mercury-cell 
chlor-alkali production process). Therefore, in addition to using the 
authority under CAA section 112(d)(4), the commenters suggested that 
EPA delete the subcategory using the authority under CAA section 
112(c)(9)(B)(ii) to avoid any uncertainty over the use of its authority 
under CAA section 112(d)(4).
    Response: The chlorine production source category was initially 
listed as a category of major sources of HAP pursuant to section 
112(c)(1) of the CAA on July 16, 1992 (57 FR 31576). Our analysis shows 
that the only HAP emitted in significant quantities from sources within 
the chlorine production source category are chlorine, HCl, and mercury, 
and mercury is only emitted from mercury cell chlor-alkali plants. 
Because of the differences in the production methods and the HAP 
emitted, we decided to divide the chlorine production category into two 
subcategories: (1) mercury cell chlor-alkali plants, and (2) chlorine 
production plants that do not rely upon mercury cells for chlorine 
production (diaphragm cell chlor-alkali plants,

[[Page 70951]]

membrane cell chlor-alkali plants, etc). Thus, on July 3, 2002, we 
issued different proposals to address the emissions of mercury from the 
mercury cell chlorine production subcategory sources (67 FR 44672) and 
the emissions of chlorine and HCl from both the non-mercury cell 
chlorine production subcategory and the mercury cell chlorine 
production subcategory sources (67 FR 44713). While we are finalizing 
the NESHAP for the mercury cell chlor-alkali subcategory in a separate 
action in today's Federal Register, with certain modifications from the 
proposal (including our decision not to regulate chlorine and HCl 
emissions under the authority of CAA section 112(d)(4)), we have 
decided to delete the non-mercury cell chlorine production subcategory 
in accordance with CAA section 112(c)(9)(B)(ii).
    We agree with those two commenters who suggested that exercising 
our authority under CAA section 112(c)(9)(B)(ii) is appropriate for 
this subcategory for a number of reasons. First, CAA section 
112(c)(9)(B)(ii) permits the deletion of subcategories, and that is 
what is at issue here. We are not deleting the entire chlorine 
production category; neither are we deleting the mercury cell 
subcategory, the emissions from which and production methodology are 
different from those facilities that produce chlorine using diaphragm 
cells, membrane cells, and the various processes that produce chlorine 
as a by-product. Second, the only HAP emitted in significant quantities 
from the facilities in this subcategory are chlorine and HCl. Chlorine 
and HCl are not carcinogens (http://www.epa.gov/iris/). Third, as 
indicated in the proposal, both of these HAP are threshold pollutants. 
For the proposed action, we obtained chlorine and HCl emission 
estimates from every known major source facility in the non-mercury 
cell chlorine production subcategory using our authority under section 
114 of the CAA and conducted risk assessments for each facility. We 
updated these assessments based on comments received. Our analysis 
showed both at the time of proposal and shows now that emissions of 
these HAP from every source in the non-mercury cell chlorine production 
subcategory do not exceed a level which is ``adequate to protect public 
health with an ample margin of safety.'' Finally, our evaluation of 
environmental effects indicates that no adverse impacts will result 
from emissions from any source within the subcategory. Therefore, we 
agree with the commenters that our evaluation is sufficient for 
delisting the subcategory under CAA section 112(c)(9)(B)(ii), and that 
such action is justified as a logical outgrowth of public comments 
received on our proposed action.
    We have reviewed in some detail the comments which have questioned 
our proposed use of CAA section 112(d)(4) to not establish NESHAP for 
chlorine and HCl emissions from facilities within the non-mercury cell 
chlorine production subcategory. We do not agree with these comments, 
and we are exercising our authority under CAA section 112(d)(4) to not 
regulate chlorine and HCl emissions from the mercury cell chlorine 
production source category. The NESHAP for the mercury cell chlorine 
subcategory is being promulgated in a separate action listed elsewhere 
in today's Federal Register. We have decided to delete the non-mercury 
cell chlorine production subcategory under CAA section 112(c)(9)(B)(ii) 
for the reasons stated above. We do not feel that we are obligated to 
exercise our authority under both CAA section 112(d)4) and CAA section 
112(c)(9)(B)(ii) as suggested by the commenter. Therefore, today's 
final action is to delete the non-mercury cell chlorine production 
subcategory under CAA section 112(C)(9)(B)(ii).
    Comment: Some commenters concluded that we did not establish either 
cancer or non-cancer thresholds for HCl and chlorine and, therefore, it 
is illegal for EPA to attempt to use CAA section 112(d)(4) to set 
standards.
    Response: Section 112(d)(4) of the CAA states that, ``With respect 
to pollutants for which a health threshold has been established, the 
Administrator may consider such threshold level, with an ample margin 
of safety, when establishing emission standards under this 
subsection.'' The threshold level refers to the level of concentration 
of a chemical under which no health effects are expected from exposure, 
although this term is not defined in CAA section 112. Further, CAA 
section 112 does not address the process that must be followed to 
establish a threshold level.
    The Reference Concentration (RfC) is a long-term threshold, defined 
as an estimate of a daily inhalation exposure that, over a lifetime, 
would not likely result in the occurrence of noncancer health effects 
in humans. We have determined that the RfC for HCl of 20 microgram per 
cubic meter ([mu]g/m3) is an appropriate threshold value for 
assessing risk to humans associated with exposure to HCl through 
inhalation http://www.epa.gov/iris/subst/0396.htm).
    In cases where we have not studied a chemical itself, we rely on 
the studies of other governmental agencies, such as the Agency for 
Toxic Substances and Disease Registry (ATSDR) or the Office of Health 
Hazard Assessment of California's Environmental Protection Agency (CAL 
EPA), for RfC values. The CAL EPA developed an RfC value of 0.2 [mu]g/
m3 for chlorine based on a large inhalation study with rats.
    Acute exposure guideline level (AEGL) toxicity values are estimates 
of adverse health effects due to a single exposure lasting eight hours 
or less. The confidence in the AEGL (a qualitative rating or either 
low, medium, or high) is based on the number of studies available and 
the quality of the data. Consensus toxicity values for effects of acute 
exposures have been developed by several different organizations, and 
we are beginning to develop such values. A national advisory committee 
organized by EPA has developed AEGL's for priority chemicals for 30-
minute, 1-hour, 4-hour, and 8-hour airborne exposures. They have also 
determined the levels of these chemicals at each exposure duration that 
will protect against discomfort (AEGL1), serious effects (AEGL2), and 
life-threatening effects or death (AEGL3). Hydrogen chloride has been 
assigned AEGL values (65 FR 39264, June 23, 2000), including the 1-
hour, AEGL1 of 2,700 [mu]g/m3 used in our revised analysis. 
Chlorine has also been assigned AEGL values (62 FR 58840), including 
the 1 hour AEGL1 of 1,500 [mu]g/m3 used in our revised 
analysis.
    We maintain that the listing of health thresholds by EPA and other 
organizations in the public domain as discussed above has established 
health thresholds for HCl and chlorine. Further, we believe that the 
recognition of these levels by EPA, ATSDR, and CAL EPA indicates that 
chlorine and HCl are threshold pollutants.
    Moreover, we provided the public an opportunity to comment on the 
thresholds for chlorine and HCl that we used in our original analysis 
for the proposed action. We used the same threshold level for HCl for 
both the proposed and final NESHAP for the pulp and paper mill 
category. (Although there is no mention of the HCl threshold in the 
final rule preamble for the pulp and paper mill NESHAP, we received no 
comment on the use of the threshold and used it in deciding not to set 
a limitation for HCl in the final NESHAP). We have also used the same 
threshold for HCl in the proposed NESHAP for lime production (67 FR 
78046). There is no requirement in either CAA section 112(d)(4) or CAA 
section 112(c)(9)(B)(ii)

[[Page 70952]]

that EPA develop or finalize a threshold for a particular HAP in a 
certain manner. In fact, CAA section 112(c)(9)(B)(ii), the authority we 
are utilizing here, does not mention the term threshold (although the 
term is implied by the use of the phrase ``a level which is adequate to 
protect public health with an ample margin of safety.'' The thresholds 
we have used for both HCl and chlorine are consistent with the 
statutory language in CAA section 112(c)(9)(B)(ii).

B. What Issues Were Raised Related to the Potential Overlap With the 
HCl Production NESHAP?

    Comment: Four commenters supported EPA's decision to include direct 
synthesis HCl as a part of the non-mercury cell chlorine production 
process. However, a commenter requested that we clarify that chlorine 
and HCl emissions from the absorber vents and associated storage 
vessels and transfer racks of the direct synthesis HCl production units 
were included in the risk analyses. To clarify applicability to the HCl 
Production NESHAP (subpart NNNNN of 40 CFR part 63), a commenter 
suggested that EPA modify the applicability provisions of subpart 
NNNNN.
    Two commenters requested that we reevaluate collocated chlorine and 
HCl production sources and provide guidance so that the facilities can 
easily determine to which source category they belong. According to the 
commenters, collocated chlorine and HCl production sources may share 
transfer operations and storage tanks, and where appropriate, we should 
remove all facilities from the HCl acid production source category that 
meet the logical test outlined in the proposed action. The commenters 
stated that they believe the collocated integrated chlorine and HCl 
acid production facilities should be placed in the non-mercury cell 
chlorine production source category and removed from the HCl production 
source category.
    Response: The final rule for subpart NNNNN of 40 CFR part 63 (68 FR 
19076, April 17, 2003) states, in Sec.  63.8985(d), that an ``HCl 
production facility is not subject to this subpart if it produces HCl 
through the direct synthesis of hydrogen and chlorine and is part of a 
chlor-alkali facility.'' The definition of ``HCl production facility'' 
in subpart NNNNN includes ``all HCl storage tanks that contain liquid 
HCl product that is produced in the HCl production unit'' (e.g., direct 
synthesis unit) as well as ``all HCl transfer operations that load HCl 
product produced in the HCl production unit into a tank truck, rail 
car, ship, or barge, along with the piping and other equipment in HCl 
service used to transfer liquid HCl product from the HCl production 
unit to the HCl storage tanks and/or HCl transfer operations.'' 
Therefore, we have clarified that chlorine and HCl emissions from the 
absorber vents of direct synthesis HCl production units at chlor-alkali 
facilities, as well as the associated storage tanks and transfer 
operations specified above, are included in the non-mercury cell 
chlorine production subcategory and are not regulated under subpart 
NNNNN.
    The clarifications we made in subpart NNNNN provide guidance for 
sources to determine to which source category their operations belong. 
As stated above, all HCl production facilities at chlor-alkali plants 
that produce HCl through direct synthesis are part of the non-mercury 
cell chlorine production subcategory. All other HCl production 
facilities (e.g., those that produce HCl as a co-product of a 
chlorinated organic compound) at sites where chlor-alkali plants are 
located are part of the HCl Production source category and subject to 
subpart NNNNN. In the case of shared storage tanks and transfer 
operations, any storage tank that stores, and any transfer operation 
that loads, liquid HCl product which was produced in an HCl production 
facility that is subject to subpart NNNNN is subject to the provisions 
of that subpart.

C. What Issues Were Raised Regarding the Risk Assessment That Forms the 
Technical Basis for This Final Action?

    Comment: In the analysis for the proposed action, we used the HCl 
RfC to determine the long-term health effects of chlorine emissions, 
since chlorine photolyzes very quickly to HCl in sunlight. Two comments 
supported that methodology and stated that our decision was based on 
sound scientific knowledge of the pollutants of concern.
    In contrast, two other commenters did not agree with our use of the 
HCl RfC as a threshold level for chlorine. The commenters stated that 
not all of the annual chlorine emissions can be considered as HCl and, 
therefore, the chlorine exposure was underestimated. The commenters 
argued that chlorine emissions will not undergo photolysis to convert 
to HCl when there is not bright sunshine (i.e., at night or on cloudy 
days).
    Response: The widely accepted fact that chlorine is photolyzed in 
sunlight formed the basis for the assumption in the original risk 
assessment that chronic exposure to chlorine would not occur. As a 
result of the comment, we re-examined the literature on the atmospheric 
fate of chlorine in the atmosphere to validate our original assumption.
    The additional information obtained from the literature confirmed 
our earlier information. There are several different pathways that 
molecular chlorine can take, including photolysis (reaction with 
light), reactions with hydroxyl radicals (OH), reactions with oxygen 
atoms (O), and reactions with water vapor (H2O). Each 
pathway results in different amounts of Cl2 being removed 
from the troposphere, and different pathways are predominant at 
different times of the day. However, photolysis is the primary pathway.
    Therefore, this information did not fundamentally change the 
assumption made in the original risk assessment, which was that on a 
long-term basis, individuals will be exposed more to hydrochloric acid 
formed from the photolysis of chlorine than to chlorine. However, the 
commenters are correct that there will be situations where individuals 
will be exposed to chlorine. Therefore, in addition to the assessment 
where we considered only acute exposure to chlorine, we concluded that 
it was appropriate to consider the effects of chronic exposure to 
chlorine emissions from chlor-alkali plants. In order to provide an 
upper bound estimate of the chronic risks to compare with the lower 
bound estimates assuming that all chlorine was converted to HCl, we 
conducted modeling assuming that no chlorine is photolyzed.
    In general, we consider an exposure concentration which is below 
the RfC concentration (what we call a hazard quotient of less than 1) 
to be safe. This is based on the definition of RfC. The RfC is a peer 
reviewed value defined as an estimate (with uncertainty spanning 
perhaps an order of magnitude) of a daily inhalation exposure to the 
human population (including sensitive subgroups) that is likely to be 
without appreciable risk of deleterious noncancer effects during a life 
time (i.e., 70 years).
    We conducted additional modeling for all facilities within the 
subcategory using the same model used for the proposed action (ISCST3) 
to estimate chronic chlorine exposure using the assumption that no 
chlorine is photolyzed to HCl. The hazard quotients resulting from this 
additional modeling defined the upper bound of our risk assessment. The 
highest upper-bound hazard quotient estimated by the model is just over 
0.3. (For more details regarding this revised risk assessment, refer to 
table 2 of the responses to

[[Page 70953]]

comment document, available in the docket.) Given the health protective 
assumptions used in this analysis, the value of 0.3 represents a 
hypothetical exposure that is well above what we would expect actual 
exposures to be. This is because chlorine is converted to HCl in the 
presence of sunlight within a few minutes. In addition, the hazard 
quotient of 0.3, which results from this exposure scenario is well 
below the safe value of 1. Thus, we have concluded that, even assuming 
that some chronic exposure to chlorine may occur, none of the sources 
included in this subcategory will have emissions of chlorine or HCl 
that exceed a level of exposure which is adequate to protect public 
health and the environment with an ample margin of safety.
    Comment: Two commenters did not support EPA's use of the AEGL2 for 
use as a short-term exposure limit for chlorine and HCl. One commenter 
stated that the AEGL2 values would not sufficiently protect public 
health because they would allow emissions at levels that cause 
discomfort, and according to the commenter, discomfort is an adverse 
health effect. The commenter also complained that EPA did not explain 
why it chose to use AEGL2 rather than AEGL1 or AEGL3. The commenter 
explained that although emissions from chlorine plants did not exceed 
AEGL2 values, the emissions may exceed AEGL1 values, and if they did, 
the proposed action would not meet the statutory requirements. Another 
commenter stated that AEGL limits are not appropriate for assessing 
daily human exposure scenarios because they were developed for 
emergency planning. The commenter recommended that EPA should use the 
American Conference of Governmental Industrial Hygienists (ACGIH), 
which has a 1-hour Short Term Exposure Limit (STEL) similar to the 
AEGL1 value of 1 parts per million (ppm) (for chlorine) and is used to 
protect against eye and mucous membrane irritation. The commenter's 
policy as a State agency is to add an additional safety factor of ten 
to ACGIH STEL values to protect for sensitive individuals, since ACGIH 
values were established for healthy workers. The commenter stressed 
that EPA must use conservative benchmarks before concluding that an 
ample margin of safety exists.
    Response: The AEGL values represent short-term threshold or ceiling 
exposure values intended for the protection of the general public, 
including susceptible or sensitive individuals, but not 
hypersusceptible or hypersensitive individuals. The AEGL values 
represent biological reference values for this defined human population 
and consist of three biological endpoints for each of four different 
exposure periods of 30 minutes, l hour, 4 hours, and 8 hours.
    The AEGL2 level is defined as follows: AEGL2 is the airborne 
concentration of a substance at or above which it is predicted that the 
general population, including susceptible, but excluding 
hypersusceptible individuals, could experience irreversible or other 
serious, long-lasting effects or impaired ability to escape. Airborne 
concentrations below the AEGL2, but at or above AEGL1 represent 
exposure levels that may cause notable discomfort.
    As utilized in the proposed action, the AEGL2 1-hour concentrations 
for chlorine and HCl are 5,800 [mu]g/m3 and 33,000 [mu]g/
m3, respectively.
    The AEGL1 level is defined as follows: AEGL-1 is the airborne 
concentration of a substance at or above which it is predicted that the 
general population, including ``susceptible'' but excluding 
``hypersusceptible'' individuals, could experience notable discomfort. 
Airborne concentrations below AEGL-1 represent exposure levels that 
could produce mild odor, taste, or other sensory irritations.
    The 1-hour AEGL1 concentration for chlorine is 2,900 [mu]g/
m3 and the corresponding value for HCl is 2,700 [mu]g/
m3. The ACGIH short term exposure limit for chlorine, which 
is 1 ppm is approximately equal to the AEGL1 value of 2,900 [mu]g/
m3.
    Although we stand by our original analysis, which used the AEGL2 
level, we have referenced the commenter's suggested use of the AEGL1 
values (possibly with a safety factor) for determining whether an ample 
margin of safety has been obtained. Therefore, we simply compared the 
short-term (1-hour average) modeling results from the original acute 
risk assessment to the AEGL1 values. These results were obtained by 
modeling the maximum allowable hourly emissions reported in the CAA 
section 114 responses for each of the sources. For plants that did not 
report fugitive emissions, fugitive emissions were estimated using 
worst-case emission factors.
    The maximum modeled 1-hour chlorine concentration for 16 of the 20 
plants is less than 5 percent of the AEGL-1 (and ACGIH) value for 
chlorine. Further, the highest modeled concentration for any plant, 346 
[mu]g/m3, is less than 12 percent of the AEGL1 values. The 
highest modeled 1-hour HCl concentration for any plant, 120 [mu]g/
m3, is less than 5 percent of the AEGL1 value for HCl.
    Based on that comparison, we conclude that the chlorine and HCl 
emissions from non-mercury cell chlorine production plants do not 
represent an unsafe level of acute exposure. Further, we maintain, 
along with the chlorine exposure assessment, that proves that an ample 
margin of safety is provided with no additional control.
    Comment: Two commenters supported EPA's method of selecting a risk 
assessment approach to meet the unique needs of the chlorine production 
industry. The commenters agreed that the risk assessment methodology 
should not be interpreted as a standardized approach that would set a 
precedent for how EPA will apply CAA section 112(d)(4) in future cases. 
Furthermore, the commenters stated that degree of conservatism built 
into all aspects of the risk assessment conducted for the chlorine 
production source category could vary greatly in future risk 
assessments for other source categories. The commenters stressed that 
they believe that the conservative assumptions made in the health 
effects assessment, emissions estimates, and exposure assessment were 
appropriate for the proposed action.
    In contrast, one commenter stated that the risk assessment fell 
short of the Agency's prior practice. According to the commenter, 
whenever EPA has made determinations to regulate a specific pollutant 
based on health considerations (e.g., national ambient air quality 
standards (NAAQS) for ozone and particulate matter (PM), the Agency 
evaluated health effects and exposure in great detail. The commenter 
contended that in that case, EPA appears to be content with ``the bare 
and unsupported assumptions about what health levels are safe.'' The 
commenter argued that it was not appropriate for EPA to use a rigorous 
approach when setting standards and a more cursory approach when making 
a decision not to regulate.
    Response: We disagree with the one commenter's characterization of 
the assessment that forms the basis for this decision, and we strongly 
dispute the characterization of the assessment as ``bare and 
unsupported.'' We maintain that the RfC and AEGL values used as 
benchmarks for the assessment are scientifically sound and appropriate. 
The emissions data and other inputs used for this analysis, which were 
provided by the industry and checked by our staff, are representative 
of the industry.
    In this assessment, the predicted health effects estimated, using 
very conservative inputs and assumptions, were well below the 
recognized health

[[Page 70954]]

thresholds. While our approach in this particular action may not be the 
same as an approach for a NAAQS, it has been certainly more than 
cursory. We have looked at emissions and exposure data for each of the 
sources in the subcategory. We have established hazard indices for 
chlorine and HCl for each source in the subcategory. We performed a 
qualitative ecological assessment. Moreover, in response to comment 
received, we have adjusted our analyses and taken into account comments 
that we have received when performing these re-assessments. We will 
base each risk assessment for this and future regulatory action on 
sound scientific principles.
    Comment: In the proposed action, the risk assessment modeling was 
conducted by placing receptors at the geographic center of census 
blocks within 2 kilometers of the site and in the population-weighted 
centers of census block groups or census tracks out to 50 kilometers. 
Two commenters did not agree with that methodology for determining 
receptor location for threshold pollutants. One commenter stated that 
EPA's methodology would be more appropriate for cancer causing agent, 
where the risk is based on probabilities of health effects. The 
commenter argued that for non-cancer (i.e., threshold pollutants) 
compounds, placing the receptors at the center of census tracks would 
not properly identify the highest impacts close to the facility. They 
felt that it was more appropriate to measure the exposure of the most 
exposed individual (e.g., someone living at the fence line of a 
facility or directly downwind).
    Response: We agree with the commenters that the greatest impacts 
will likely occur near the facility for this source category. However, 
we do not agree with the commenters that our approach fails to meet 
statutory requirements. We do not feel that considering an ``ample 
margin of safety'' means that we must demonstrate no risk or adverse 
health effects for a theoretical person living at the fence line. 
Rather, we feel it is appropriate to assess the risks at locations 
where people most likely reside. A census block is the smallest 
geographic unit for which the Census Bureau tabulates 100-percent data. 
While census blocks in rural areas may be larger, many blocks 
correspond to individual city blocks in more populated areas. The 
commenter is correct in that an individual could live closer to the 
plant than the center of the census block, and our approach would have 
slightly underestimated risk. It is just as likely, however, that the 
closest individual could live farther from the plant than the center of 
the census block causing our risk estimates to be slightly 
overestimated. By placing receptors at the center of populated census 
blocks on all sides of a facility, we have evaluated people living 
downwind. In conclusion, we continue to feel that placing a receptor in 
the geographic center of populated census blocks near a facility is a 
well established approach to exposure modeling which results in a 
reasonable approximation of estimating the risks where people actually 
live, and we maintain that this methodology is appropriate for actions 
taken under the authority of either CAA section 112(d)(4) or CAA 
section 112(c)(9)(B)(ii).
    Comment: One commenter stated that the total chlorine and HCl 
emissions from some of the facilities included in the risk assessment 
were grossly underestimated. In support of their argument, the 
commenter pointed out potential inconsistencies in the background 
emissions data contained in the docket. Specifically, the total 
chlorine emissions from the Dow Chemicals, Freeport, Texas facility 
were reported in the risk assessment document to be 22 pounds per year 
(lb/yr), but in the 1996 Chlorine Production Summary Report, chlorine 
emissions from only one production process located at the Dow Chemicals 
facility (the diaphragm cell process) were reported to be 9,800 lb/yr. 
The commenter stated that since emissions from other processes at the 
Dow facility were not included in the summary report, the emissions 
were likely to be much higher. The commenter also noted that the Dow 
facility had the lowest emissions (22 lb/yr) of facilities reported in 
the risk assessment document and the highest chlorine production volume 
(1.8 million lb Cl2/yr), which also indicates that the 
emissions from the Dow facility were underestimated.
    According to the commenter, the inconsistencies between the reports 
undermine the credibility of the risk assessment to support a decision 
to not regulate this source category. Furthermore, the commenter stated 
that they believe that the emission inventory information provides 
justification for a need to establish a MACT floor. The commenter 
concluded that the risk assessment was flawed because the potential 
impacts on health and the environment were underestimated.
    Response: The primary sources of the emission estimates used in the 
risk assessment for this source category were responses submitted 
directly by the facilities in response to a request for information 
under our authority in section 114 of the Clean Air Act. A review of 
the data was conducted as they were received, and follow-up questions 
asked of the industry representatives to clarify the information 
submitted. After the analysis, we were satisfied with the quality of 
the data, with one exception. Only one-half of the facilities submitted 
chlorine emission estimates from fugitive sources. One of the areas of 
focus in the follow-up questions was to verify the fugitive emission 
estimates for those facilities that did submit such estimates. Our 
conclusion was that fugitive emissions are to be expected from every 
non-mercury cell chlorine production plant, so we estimated fugitive 
emissions for those that did not submit estimates. That was done using 
the highest emission factor calculated from the plants that did report 
fugitives. The use of the ``worst-case'' factor was appropriately 
conservative for this assessment.
    The commenter compared the emissions used in the assessment to 
1991/1992 base year emissions in an earlier report on this industry, 
the 1996 Chlorine Production Summary Report, and correctly noted that 
there is a large discrepancy between the emissions levels for Dow 
Chemical's plant in Freeport, Texas. As a result of that comment, we 
made a comparison of the emissions from all plants between these two 
sources of information.
    The comparison revealed that the Dow Freeport facility is only one 
of only two plants whose emissions used in the risk assessment were 
lower than the 1991/1992 base year emissions in the 1996 summary 
report. In fact, the 2000/2001 emissions used in the risk assessment 
for the other facilities with reported emissions in both documents 
averaged five times HIGHER than those reported in the 1996 summary 
document. Clearly, the comparison does not lead to the conclusion that 
the risk assessment was based on grossly underestimated emissions. A 
review of the data submitted by the two facilities whose 2000/2001 
emissions were substantially lower than their 1991/1992 emissions did 
not result in any obvious errors or questionable assumptions that could 
be disputed with the available information. Furthermore, according to 
the facility, the chlorine and HCl emissions reported in the 1996 
summary document included emissions from processes within the plant not 
related to chlorine production. That was corrected for the 2000/2001 
emissions data submittal. Therefore, no changes were made as a result 
of the review of the reported emissions data.
    The comparison did result in the concern that the emissions, 
particularly

[[Page 70955]]

the fugitive emissions estimated using the worst-case factor, had been 
overestimated. As a point of comparison, we obtained the 2001 chlorine 
releases from the Toxic Release Inventory (TRI) for all ten sites for 
which fugitive emissions were estimated using the worst-case factor. We 
found that nine of the ten plants had total chlorine fugitive releases 
reported in TRI that were less than the those used in the risk 
assessment. For instance, the PPG facility in Lake Charles, Louisiana, 
reported 8,000 lb/yr of fugitive chlorine releases for the entire site 
(a very large chemical complex). We estimated 31,178 lb/yr using the 
worst-case emission factor. We concluded that it was overly 
conservative to use these estimates in light of the TRI information and 
in fact, we likely overestimated the fugitive emissions for these 
plants. Therefore, in the revised modeling for this final action for 
chronic chlorine exposures, we used the total chlorine fugitive 
releases from TRI in the revised assessment for eight plants. That is 
still conservative as these TRI values represent chlorine fugitive 
releases from all processes at the site, not just the non-mercury cell 
chlorine production processes. For two plants, company representatives 
provided a breakdown of the portion of the TRI emissions that were from 
the non-mercury cell chlorine production processes, and those values 
were used in the re-assessment.
    Comment: One commenter stated that all chlorine emissions from non-
mercury chlorine production facilities that are collocated with other 
source categories need to be reviewed as a whole when evaluating public 
health risk, adverse environmental effects, and possible control 
strategies. The commenter stressed that other sources of chlorine and 
HCl should be included in the risk assessment under CAA section 
112(d)(4). The commenter was concerned that not accounting for all 
chlorine and HCl emissions from a facility would provide the community 
with a false sense of assurance of protection, and is not consistent 
with the legislative intent of the CAA to consider cumulative HAP 
exposure issues through an integrated approach under CAA sections 
112(d), 112(f), and 112(k). Therefore, the commenter requested that EPA 
evaluate the potential for adverse health and environmental impacts 
using conservative risk assessment methodology that incorporates all 
known chlorine and HCl emissions from a contiguous facility.
    Response: Section 112 of the CAA requires us to list categories and 
subcategories of major sources and area sources of HAP, and to 
establish NESHAP for the listed source categories and subcategories. In 
directing us how to establish MACT emission limits, section 112(d)(3) 
of the CAA requires us to set the emission limitation at a level that 
assures that all major sources achieve the level of control at least as 
stringent as that already achieved by the better-controlled and lower-
emitting sources in each source category or subcategory. Therefore, the 
entire MACT program is structured on a source category-specific basis. 
All MACT standards developed to date have addressed emissions from 
specific source categories.
    There are instances where non-mercury chlorine production 
facilities are collocated with other source categories. However, based 
on the risk assessment for chlorine and HCl emissions from chlor-alkali 
plants, the predicted impacts from chlorine and HCl at these chlor-
alkali plants are extremely low. We believe that the human health and 
environmental impacts from all sources in the category even when 
collocated with other chlorine and HCl emissions will still be within 
an ample margin of safety to protect the public health, and will not 
cause adverse environmental effects. Moreover, as indicated in the 
preamble to the proposed rule, most major processes at the sites where 
non-mercury cell chlorine production facilities are located are subject 
to, or will be subject to, NESHAP to reduce HAP emissions (67 FR 44714, 
July 3, 2002). Therefore, it would not be appropriate to include 
emissions from those sources in an assessment for the non-mercury cell 
chlorine production source category conducted under the authority of 
CAA section 112(d)(4).
    Comment: Two commenters stated that the environmental effects 
analysis was not adequate. One commenter stated that potential 
ecological effects of HCl emissions have not been properly referenced. 
One commenter stated that EPA's proposed action falls short of its 
obligation to protect against environmental effects. According to the 
commenter, EPA has understated its statutory obligation in the proposed 
action. The commenter referred to the legislative history, which 
indicates that CAA section 112(d)(4) requires standards that ``would 
not result in adverse environmental effects which would otherwise be 
reduced or eliminated.'' The commenter listed the several shortcomings 
in the EPA's environmental assessment.
    The commenter concluded that although EPA acknowledged that it had 
an obligation to ensure that any standards set under CAA section 
112(d)(4) did not have any adverse environmental effects, the Agency 
did not properly consider the issue. Therefore, commenter stated that 
they believed that EPA could not promulgate standards under CAA section 
112(d)(4) without contravening the CAA.
    Response: While CAA section 112(d)(4) makes no mention of 
environmental effects, we took the potential of such adverse effects 
into account when we issued our proposed action. In addition, CAA 
section 112(c)(9)(B)(ii), which is the authority we are citing in 
today's final action to delete this subcategory, does require that we 
show there are no adverse environmental effects from emissions from the 
subcategory.
    The level of our analysis at proposal was adequate to satisfy the 
requirements of CAA section 112(c)(9)(B)(ii). The commenters did not 
suggest that they believed there was the potential for adverse 
environmental effects from HCl or chlorine emissions from non-mercury 
cell chlorine production plants. Were there any evidence that such 
adverse effects were likely, or even possible, we would have conducted 
a more intensive ecological risk assessment.
    The commenters are correct, however, that we did not discuss the 
ecological effects of chlorine. That was because, as was stated in the 
proposal preamble, we did not perform a separate evaluation of chronic 
chlorine exposure because chlorine is converted to HCl in the 
atmosphere so rapidly. Following is a brief summary of the 
environmental effect of chlorine.
    Atmospheric exposure is the primary pathway for environmental 
effects from chlorine emissions. However, since most chlorine is 
converted to HCl, studies have focused on the effects of HCl on 
vegetation. Although plant exposures to elevated levels of chlorine can 
cause plant injury, it tends to be converted to other, less toxic forms 
rather rapidly in plants, and may not result in the direct accumulation 
of toxic pollutant residuals important in the food chain.
    Plant studies have found foliar damage due to chlorine emissions 
and foliar damage, decreased levels of chlorophyl a and b, decreased 
leaf areas, obvious chlorosis, and a decline in fruit production due to 
chlorine emissions.
    There is evidence of effects to animals due to accidental and/or 
catastrophic exposures, but the chlorine concentrations of these 
exposures are unknown. However, there is no data on exposure to 
historic or atmospheric concentrations.

[[Page 70956]]

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

IV. Statutory and Executive Order Reviews

A. Executive Order 12866: Regulatory Planning and Review

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

B. Paperwork Reduction Act

    Since there is no rule associated with this final action, there are 
no information collection requirements.

C. Regulatory Flexibility Act

    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, small organizations, and small 
governmental jurisdictions.
    For purposes of assessing the impacts of today's rule on small 
entities, small entity is defined as: (1) A small business as defined 
by the Small Business Administrations' regulations at 13 CFR 121.201; 
(2) a small governmental jurisdiction that is a government of a city, 
county, town, school district or special district with a population of 
less than 50,000; and (3) a small organization that is any not-for-
profit enterprise which is independently owned and operated and is not 
dominant in its field.
    After considering the economic impacts of today's final rule on 
small entities, I certify that this action will not have a significant 
economic impact on a substantial number of small entities. This final 
action deletes the subcategory of sources that do not utilize mercury 
cells to produce chlorine and caustic. We conclude that no further 
control or regulation is necessary.

D. Unfunded Mandates Reform Act

    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 cost-
benefit analysis, for proposed and final rules with ``Federal 
mandates'' that may result in expenditures by State, local, and Tribal 
governments, in aggregate, or to the private sector, of $100 million or 
more in any 1 year. Before promulgating an EPA rule for which a written 
statement is needed, section 205 of the UMRA generally requires us to 
identify and consider a reasonable number of regulatory alternatives 
and adopt the least costly, most cost-effective, or least burdensome 
alternative that achieves the objectives of the rule. The provisions of 
section 205 do not apply when they are inconsistent with applicable 
law. Moreover, section 205 allows us to adopt an alternative other than 
the least costly, most cost-effective, or least burdensome alternative 
if we publish with the final rule an explanation as to why that 
alternative was not adopted.
    Before we establish any regulatory requirements that may 
significantly or uniquely affect small governments, including Tribal 
governments, we must have developed under section 203 of the UMRA, a 
small government agency plan. The plan must provide for notifying 
potentially affected small governments, enabling officials of affected 
small governments to have meaningful and timely input in the

[[Page 70957]]

development of our regulatory proposals with significant Federal 
intergovernmental mandates, and informing, educating, and advising 
small governments on compliance with the regulatory requirements.
    We have determined that this final action 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. Thus, today's final action is not subject 
to the requirements of sections 202 and 205 of the UMRA. In addition, 
this final action contains no regulatory requirements. Therefore, the 
final action is not subject to the requirements of section 203 of the 
UMRA.

E. Executive Order 13132: Federalism

    Executive Order 13132 (64 FR 43255, August 10, 1999) requires EPA 
to develop an accountable process to ensure ``meaningful and timely 
input by State and local officials in the development of regulatory 
policies that have federalism implications.'' ``Policies that have 
federalism implications'' is defined in the Executive Order to include 
regulations that have ``substantial direct effects on the States, on 
the relationship between the national Government and the States, or on 
the distribution of power and responsibilities among the various levels 
of Government.''
    The final action does not have federalism implications. It will not 
have substantial direct effects on the States, on the relationship 
between the national Government and the States, or on the distribution 
of power and responsibilities among the various levels of Government, 
as specified in Executive Order 13132. Thus, Executive Order 13132 does 
not apply to the final action.

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

    Executive Order 13175 (65 FR 67249, November 6, 2000) requires EPA 
to develop an accountable process to ensure ``meaningful and timely 
input by Tribal officials in the development of regulatory policies 
that have tribal implications.'' ``Policies that have Tribal 
implications'' 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 final action 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 final action.

G. Executive Order 13045: Protection of Children From Environmental 
Health 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. 
Since there is no rule associated with this final action, Executive 
Order 13045 does not apply.

H. Executive Order 13211: Actions That Significantly Affect Energy 
Supply, Distribution, or Use

    The final action 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.

I. National Technology Transfer Advancement Act

    Section 12(d) of the National Technology Transfer Advancement Act 
(NTTAA) of 1995 (Public Law 104-113; 15 U.S.C. 272 note) directs EPA to 
use voluntary consensus standads in their regulatory and procurement 
activities unless to do so would be inconsistent with applicable law or 
otherwise impractical. Voluntary consensus standards are technical 
standards (e.g., materials specifications, test methods, sampling 
procedures, business practices) developed or adopted by one or more 
voluntary consensus bodies. The NTTAA directs EPA to provide Congress, 
through annual reports to the Office of Management and Budget (OMB), 
with explanations when an agency does not use available and applicable 
voluntary consensus standards.
    The final action does not involve technical standards, therefore, 
the NTTAA does not apply.

J. Congressional Review Act

    The Congressional Review Act, 5 U.S.C. 801 et seq., as added by the 
Small Business Regulatory Enforcement Fairness Act of 1996, generally 
provides that before a rule may take effect, the agency promulgating 
the rule must submit a rule report, which includes a copy of the rule, 
to each House of the Congress and to the Comptroller General of the 
United States. Today's final action is not a rule, therefore, the 
Congressional Review Act does not apply.

List of Subjects in 40 CFR Part 63

    Environmental protection, Air emissions control, Hazardous air 
pollutants.

    Dated: August 29, 2003.
Marianne L. Horinko,
Acting Administrator.
[FR Doc. 03-22929 Filed 12-18-03; 8:45 am]
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