[Federal Register Volume 76, Number 200 (Monday, October 17, 2011)]
[Rules and Regulations]
[Pages 64022-64037]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2011-23534]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 372

[EPA-HQ-TRI-2009-0844; FRL-9463-5]
RIN 2025-AA27


Hydrogen Sulfide; Community Right-to-Know Toxic Chemical Release 
Reporting

AGENCY: Environmental Protection Agency (EPA).

ACTION: Lifting of Administrative Stay for Hydrogen Sulfide.

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SUMMARY: EPA is announcing that it is lifting the Administrative Stay 
of the Emergency Planning and Community Right-to-Know Act (EPCRA) 
section 313 toxic chemical release reporting requirements for hydrogen 
sulfide (Chemical Abstracts Service Number (CAS No.) 7783-06-4). 
Hydrogen sulfide was added to the EPCRA section 313 list of toxic 
chemicals in a final rule published in the Federal Register on

[[Page 64023]]

December 1, 1993. However, on August 22, 1994, EPA issued an 
Administrative Stay of the reporting requirements for hydrogen sulfide 
in order to evaluate issues brought to the Agency's attention after 
promulgation of the final rule concerning the human health effect basis 
for the listing and the Agency's use of exposure analysis in EPCRA 
section 313 listing decisions. Although the final rule listing hydrogen 
sulfide under section 313 of EPCRA remained in force, the stay deferred 
the reporting requirements for hydrogen sulfide while EPA completed 
this further evaluation. EPA completed its further evaluation of 
additional information that has become available since the stay was put 
in place regarding the human health and environmental effects of 
hydrogen sulfide, and the Agency published a position that the stay 
should be lifted in the February 26, 2010, Federal Register document 
``Intent to Consider Lifting Administrative Stay; Opportunity for 
Public Comment.'' Based on EPA's further evaluation and the 
consideration of the public comments received on the notice of intent, 
EPA continues to believe that the Administrative Stay should be lifted. 
By this current action, EPA is not revisiting the original listing 
decision, which was accomplished by final rule on December 1, 1993. 
Rather, EPA is lifting the Administrative Stay of the reporting 
requirements for hydrogen sulfide.

DATES: This action is effective on October 17, 2011, such that the 
first reports on hydrogen sulfide will be due on July 1, 2013 for 
reporting year 2012.

ADDRESSES: EPA has established a docket for this action under Docket ID 
No. EPA-HQ-TRI-2009-0844. All documents in the docket are listed in the 
http://www.regulations.gov index. Although listed in the index, some 
information is not publicly available, e.g., CBI or other information 
whose disclosure is restricted by statute. Certain other material, such 
as copyrighted material, will be publicly available only in hard copy. 
Publicly available docket materials are available either electronically 
in http://www.regulations.gov or in hard copy at the OEI Docket, EPA/
DC, EPA West, Room 3334, 1301 Constitution Ave., NW., Washington, DC. 
This Docket Facility is open from 8:30 a.m. to 4:30 p.m., Monday 
through Friday, excluding legal holidays. The telephone number for the 
Public Reading Room is (202) 566-1744, and the telephone number for the 
OEI Docket is (202) 566-1752.

FOR FURTHER INFORMATION CONTACT: Daniel R. Bushman, Environmental 
Analysis Division, Office of Information Analysis and Access (2842T), 
Environmental Protection Agency, 1200 Pennsylvania Ave., NW., 
Washington, DC 20460; telephone number: 202-566-0743; fax number: 202-
566-0677; e-mail: [email protected], for specific information on 
this document. For general information on EPCRA section 313, contact 
the Emergency Planning and Community Right-to-Know Hotline, toll free 
at (800) 424-9346 or (703) 412-9810 in Virginia and Alaska or toll 
free, TDD (800) 553-7672, http://www.epa.gov/epaoswer/hotline/.

SUPPLEMENTARY INFORMATION:

I. General Information

A. Does this action apply to me?

    You may be potentially affected by this action if you manufacture, 
process, or otherwise use hydrogen sulfide. Potentially affected 
categories and entities may include, but are not limited to:

----------------------------------------------------------------------------------------------------------------
                  Category                                 Examples of potentially affected entities
----------------------------------------------------------------------------------------------------------------
Industry....................................  Facilities included in the following NAICS manufacturing codes
                                               (corresponding to SIC codes 20 through 39): 311*, 312*, 313*,
                                               314*, 315*, 316, 321, 322, 323*, 324, 325*, 326*, 327, 331, 332,
                                               333, 334*, 335*, 336, 337*, 339*, 111998*, 211112*, 212324*,
                                               212325*, 212393*, 212399*, 488390*, 511110, 511120, 511130,
                                               511140*, 511191, 511199, 512220, 512230*, 519130*, 541712*, or
                                               811490*.
                                              *Exceptions and/or limitations exist for these NAICS codes.
                                              Facilities included in the following NAICS codes (corresponding to
                                               SIC codes other than SIC codes 20 through 39): 212111, 212112,
                                               212113 (correspond to SIC 12, Coal Mining (except 1241)); or
                                               212221, 212222, 212231, 212234, 212299 (correspond to SIC 10,
                                               Metal Mining (except 1011, 1081, and 1094)); or 221111, 221112,
                                               221113, 221119, 221121, 221122, 221330 (Limited to facilities
                                               that combust coal and/or oil for the purpose of generating power
                                               for distribution in commerce) (correspond to SIC 4911, 4931, and
                                               4939, Electric Utilities); or 424690, 425110, 425120 (Limited to
                                               facilities previously classified in SIC 5169, Chemicals and
                                               Allied Products, Not Elsewhere Classified); or 424710
                                               (corresponds to SIC 5171, Petroleum Bulk Terminals and Plants);
                                               or 562112 (Limited to facilities primarily engaged in solvent
                                               recovery services on a contract or fee basis (previously
                                               classified under SIC 7389, Business Services, NEC)); or 562211,
                                               562212, 562213, 562219, 562920 (Limited to facilities regulated
                                               under the Resource Conservation and Recovery Act, subtitle C, 42
                                               U.S.C. 6921 et seq.) (correspond to SIC 4953, Refuse Systems).
Federal Government..........................  Federal facilities.
----------------------------------------------------------------------------------------------------------------

    This table is not intended to be exhaustive, but rather provides a 
guide for readers regarding entities likely to be affected by this 
action. Some of the entities listed in the table have exemptions and/or 
limitations regarding coverage, and other types of entities not listed 
in the table could also be affected. To determine whether your facility 
would be affected by this action, you should carefully examine the 
applicability criteria in part 372 subpart B of Title 40 of the Code of 
Federal Regulations. 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.

II. Introduction

    Section 313 of EPCRA, 42 U.S.C. 11023, requires certain facilities 
that manufacture, process, or otherwise use listed toxic chemicals in 
amounts above reporting threshold levels to report their environmental 
releases and other waste management quantities of such chemicals 
annually. These facilities must also report pollution prevention and 
recycling data for such chemicals, pursuant to section 6607 of the 
Pollution Prevention Act (PPA), 42 U.S.C. 13106. EPCRA section 313 
established an initial list of toxic chemicals composed of more than 
300 chemicals and 20 chemical categories.
    EPCRA section 313(d) authorizes EPA to add or delete chemicals from 
the list and sets forth criteria for these actions. Specifically, EPCRA 
section 313(d)(2) states that EPA may add a chemical to the list if 
``there is sufficient evidence to establish any one'' of the listing 
criteria. Therefore, to add a chemical, EPA must demonstrate that at 
least one criterion is met, but need not determine whether any other 
criterion is met. Conversely, EPCRA section 313(d)(3) states that to 
remove a chemical from the list, EPA must determine that ``there is not 
sufficient evidence to establish any'' of

[[Page 64024]]

the Section 313(d)(2) criteria. Therefore, to remove a chemical, EPA 
must demonstrate that none of the criteria are met. The EPCRA section 
313(d)(2) criteria are:
    (A) The chemical is known to cause or can reasonably be anticipated 
to cause significant adverse acute human health effects at 
concentration levels that are reasonably likely to exist beyond 
facility site boundaries as a result of continuous, or frequently 
recurring, releases.
    (B) The chemical is known to cause or can reasonably be anticipated 
to cause in humans--
    (i) Cancer or teratogenic effects, or
    (ii) Serious or irreversible--
    (I) Reproductive dysfunctions,
    (II) Neurological disorders,
    (III) Heritable genetic mutations, or
    (IV) Other chronic health effects.
    (C) The chemical is known to cause or can be reasonably anticipated 
to cause, because of
    (i) Its toxicity,
    (ii) Its toxicity and persistence in the environment, or
    (iii) Its toxicity and tendency to bioaccumulate in the 
environment, a significant adverse effect on the environment of 
sufficient seriousness, in the judgment of the Administrator, to 
warrant reporting under this section.
    EPA often refers to the section 313(d)(2)(A) criterion as the 
``acute human health effects criterion;'' the section 313(d)(2)(B) 
criterion as the ``chronic human health effects criterion;'' and the 
section 313(d)(2)(C) criterion as the ``environmental effects 
criterion.''
    Under EPCRA section 313(e)(1), any person may petition EPA to add 
chemicals to or delete chemicals from the list. EPA issued a statement 
of petition policy and guidance in the Federal Register of February 4, 
1987 (52 FR 3479) to provide guidance regarding the recommended content 
and format for submitting petitions under EPCRA section 313(e). EPA 
also issued guidance in the Federal Register of May 23, 1991 (56 FR 
23703) regarding the recommended content of petitions to delete 
individual members of the section 313 metal compound categories. In 
addition, EPA published in the Federal Register of November 30, 1994 
(59 FR 61432) a statement clarifying its interpretation of the section 
313(d)(2) and (d)(3) criteria for modifying the section 313 list of 
toxic chemicals.

III. Background Information

A. What is the history of the listing of hydrogen sulfide under EPCRA 
section 313?

    In response to a petition from the Natural Resources Defense 
Council and the Governor of New York, hydrogen sulfide, along with 20 
other chemicals and two chemical categories, was added to the EPCRA 
section 313 list of toxic chemicals as part of a 1993 final rule 
(December 1, 1993, 58 FR 63500). Hydrogen sulfide was listed under the 
criteria of EPCRA section 313(d)(2)(B) (chronic human health effects) 
based on chronic neurotoxic effects in humans and under EPCRA section 
313(d)(2)(C) (environmental effects) based on acute aquatic toxicity. 
However, on August 22, 1994 (59 FR 43048), EPA issued an Administrative 
Stay of the EPCRA section 313 reporting requirements for hydrogen 
sulfide. Although the final rule listing hydrogen sulfide under section 
313 of EPCRA remained in force, the stay deferred the reporting 
requirements for hydrogen sulfide. On February 26, 2010, EPA issued a 
document in the Federal Register entitled ``Intent to Consider Lifting 
Administrative Stay; Opportunity for Public Comment'' (75 FR 8889). 
That document provided the public with the opportunity to comment on 
EPA's review of the currently available data on the human health and 
environmental effects of hydrogen sulfide--specifically, chronic 
respiratory effects, chronic neurotoxic effects, and acute, chronic and 
early-life stage aquatic toxicity--and EPA's belief that the 
Administrative Stay should be lifted based on that data.

B. What was the basis for the administrative stay?

    After the final rule was issued adding hydrogen sulfide to the 
EPCRA section 313 list of toxic chemicals, some members of the 
regulated community expressed a concern that the ``chronic human health 
effects'' basis for listing hydrogen sulfide under EPCRA section 
313(d)(2)(B) had changed between the proposed rule (September 8, 1992, 
57 FR 41020) and the final rule (December 1, 1993, 58 FR 63500), and 
that commenters on the proposed rule therefore did not have an 
opportunity to comment on that individual basis for the listing. 
Specifically, although the Agency cited the same acute aquatic toxicity 
as an ``environmental effects'' basis for the listing under EPCRA 
section 313(d)(2)(C) in both the proposed and final rules, the Agency 
also cited chronic respiratory effects as a ``chronic human health 
effects'' basis under EPCRA section 313(d)(2)(B) in the proposed rule, 
but chronic neurotoxic effects as a ``chronic human health effects'' 
basis under that same provision in the final rule. In addition, after 
issuance of the final rule, some members of the regulated community 
expressed concern that EPA's decision not to include an exposure 
analysis in deciding to list hydrogen sulfide on the basis of chronic 
human health effects was inconsistent with past Agency practice.
    Although EPA did not agree that it had been inconsistent in its use 
of exposure analyses, and notwithstanding the fact that the listing 
decision was appropriate based on the acute aquatic toxicity finding 
alone under EPCRA section 313(d)(2)(C), the Agency issued an 
Administrative Stay of the reporting requirements for hydrogen sulfide 
in order to review the concerns raised after issuance of the final rule 
by some members of the regulated community.

C. What is EPA's rationale for lifting the administrative stay for 
hydrogen sulfide?

    EPA's technical evaluation of hydrogen sulfide, as discussed in 
detail in the February 26, 2010 Federal Register document (75 FR 8889), 
shows that it can reasonably be anticipated to cause chronic health 
effects in humans. The chronic health effects have been observed in 
laboratory animals at concentrations as low as 28 milligrams per cubic 
meter (mg/m\3\) (20 parts per million (ppm)) for neurotoxicity and 41.7 
mg/m\3\ (30 ppm) for upper respiratory toxicity. In addition, EPA's 
technical evaluation of hydrogen sulfide also shows that it can 
reasonably be anticipated to cause, because of its toxicity, 
significant adverse effects in aquatic organisms. Examples of hydrogen 
sulfide's ecological toxicity include acute toxicity (96-hour 
LC50 (i.e., the concentration that is lethal to 50% of test 
organisms)) values for freshwater fish that ranged from 0.0149 
milligrams per liter (mg/L) (fathead minnow) to 0.0448 mg/L (bluegill), 
indicating high aquatic toxicity. Examples of hydrogen sulfide's 
chronic ecological toxicity include freshwater fish values that ranged 
from a 6-week lowest-observed-effect-concentration (LOEC) (growth rate) 
of 0.0005 mg/L in a tropical fish (Mystus nemurus) to a 430-day LOEC 
(final weight) of 0.009 mg/L for goldfish, also indicating high aquatic 
toxicity.
    Based on the above findings, EPA believes that there is no basis 
for continuing the Administrative Stay of the reporting requirements 
for hydrogen sulfide, and that the Administrative

[[Page 64025]]

Stay should therefore be lifted. As an aside, EPA notes also that it 
believes that the above findings clearly demonstrate the correctness of 
the Agency's final decision in December 1993 to list hydrogen sulfide 
on the EPCRA section 313 toxic chemicals list based on the listing 
criteria in EPCRA sections 313(d)(2)(B) and (C).
    Finally, in accordance with EPA's stated policy on the use of 
exposure assessments (59 FR 61432), EPA does not believe that an 
exposure assessment is appropriate for determining whether hydrogen 
sulfide meets the criteria of EPCRA section 313(d)(2)(B) or (C), and 
therefore the Administrative Stay should not be continued for lack of 
an exposure analysis. As EPA explained in the Intent to Lift the Stay 
(and as explained in Unit IV.A.1.c. of this Notice):

    EPA has determined that hydrogen sulfide can reasonably be 
anticipated to cause serious or irreversible chronic human health 
effects at relatively low doses and thus is considered to have 
moderately high to high chronic toxicity. EPA does not believe that 
it is appropriate to consider exposure for chemicals that are 
moderately high to highly toxic based on a hazard assessment when 
determining if a chemical can be listed for chronic effects pursuant 
to EPCRA section 313(d)(2)(B) (see 59 FR 61432, 61433, 61440-61442). 
Hydrogen sulfide has also been determined to cause ecotoxicity at 
relatively low concentrations, and thus is considered to have high 
ecotoxicity. EPA believes that chemicals that induce death or 
serious adverse effects in aquatic organisms at relatively low 
concentrations (i.e., they have high ecotoxicity) have the potential 
to cause significant changes in the population of fish and other 
aquatic organisms, and can therefore reasonably be anticipated to 
cause a significant adverse effect on the environment of sufficient 
seriousness to warrant reporting. EPA does not believe that it is 
required to consider exposure for chemicals that have high 
ecotoxicity based on a hazard assessment when determining if a 
chemical can be listed for effects pursuant to EPCRA section 
313(d)(2)(C) (see 59 FR 61432, 61433, 61440-61442). (75 FR 8889, 
8893 (Feb. 26, 2010)).

D. What is the purpose of this document?

    The purpose of this document is to respond to the public comments 
received on EPA's February 26, 2010, Federal Register document ``Intent 
to Consider Lifting Administrative Stay; Opportunity for Public 
Comment'' (75 FR 8889), and to give notice that EPA is lifting the 
Administrative Stay of the EPCRA section 313 toxic chemical release 
reporting requirements for hydrogen sulfide. With the lifting of this 
stay, pursuant to Section 313 of EPCRA, certain facilities that 
manufacture, process, or otherwise use hydrogen sulfide in amounts 
above reporting threshold levels must now comply with the reporting 
requirements that have been in place since hydrogen sulfide was added 
to the EPCRA section 313 list in 1993. The first reports on hydrogen 
sulfide will be due on July 1, 2013 for reporting year 2012.

IV. What comments did EPA receive on the intent to consider lifting the 
administrative stay and what are EPA's responses to those comments?

    EPA received fifteen comments on the Federal Register document 
``Intent to Consider Lifting Administrative Stay; Opportunity for 
Public Comment'' (75 FR 8889). The comments represented 6 individuals, 
32 environmental groups, one state agency, and 10 industry groups. 
Environmental groups that commented included the Food & Water Watch, 
National Association of Clean Water Agencies, Natural Resources Defense 
Council, Waterkeeper Alliance and one comment submitted by 28 other 
environmental organizations. The comments from the individuals, 
environmental groups, and state agency were supportive of EPA's intent 
to lift the Administrative Stay. Many of these groups provided 
additional information to support EPA's action as well as requesting 
other actions such as listing additional industry sectors that have 
significant releases of hydrogen sulfide. The most extensive comments 
came from the Hydrogen Sulfide Consortium, whose members are: American 
Coke and Coal Chemicals Institute, American Forest and Paper 
Association, American Petroleum Institute, Asphalt Institute, Carbon 
Disulfide Coalition, Corn Refiners Association, National Petrochemical 
and Refiners Association, and The Sulphur Institute. The most 
significant opposing comments are summarized and responded to below. 
The complete set of comments and EPA's responses can be found in the 
response to comment document in the docket for this action (Ref. 1).

A. Comments From the Hydrogen Sulfide Consortium

    1. Scope of Comments. Commenters claim that ``EPA cannot properly 
limit comments to whether or not EPA should lift its Administrative 
Stay of EPCRA section 313 reporting requirements,'' but rather must 
revisit the original listing decision accomplished by final rule in 
1993. In support of this argument, commenters assert that: (1) EPA 
stated, when it issued the Administrative Stay in 1994, that it would 
revisit the original listing decision; (2) EPA cited chronic 
respiratory effects as one of the bases for listing under EPCRA section 
313(d)(2)(B) in the proposed rule, but chronic neurotoxic effects as a 
basis under that same provision in the final rule; (3) EPA adopted its 
current policy regarding exposure analyses subsequent to the 1993 
listing of hydrogen sulfide; and (4) EPA ``must make a new listing 
determination before it may lift [the stay].''
    For the reasons stated below, EPA disagrees with commenters that 
EPA must revisit the original listing decision in the context of EPA's 
consideration of lifting the Administrative Stay of the EPCRA reporting 
requirements for hydrogen sulfide. Based upon our current review of the 
science, as presented in EPA's technical evaluation of hydrogen 
sulfide, which is discussed in detail in the February 26, 2010 Federal 
Register document (75 FR 8889) and summarized in Unit III.C. of this 
document, EPA has determined that there is no need to re-visit the 
existing listing determination. Before addressing each of the 
commenter's arguments in turn, however, a brief reiteration of the 
factual background is useful.
    As described in detail below, EPCRA section 313(d)(2) states that 
EPA may add a chemical to the list if ``there is sufficient evidence to 
establish any one'' (emphasis added) of the listing criteria specified 
in section 313(d)(2). Therefore, to add a chemical, EPA must 
demonstrate that at least one criterion is met, but need not determine 
whether any other criterion is met.
    EPA proposed to add hydrogen sulfide to the EPCRA section 313 list 
of toxic chemicals on September 8, 1992 (57 FR 41020) based on a 
determination that there was sufficient evidence establishing both 
chronic human health effects per EPCRA section 313(d)(2)(B) 
(specifically, chronic respiratory effects) and environmental effects 
per EPCRA section 313(d)(2)(C) (specifically, acute aquatic toxicity). 
On December 1, 1993, EPA promulgated a final rule adding hydrogen 
sulfide to the EPCRA section 313 list of toxic chemicals (58 FR 63500) 
(effective January 1, 1994). In the final rule, the listing decision 
was based on a determination that there was sufficient evidence 
establishing environmental effects per EPCRA section 313(d)(2)(C) 
(specifically, the same acute aquatic toxicity as identified in the 
proposed rule) and chronic human health effects per EPCRA section 
313(d)(2)(B). In the final rule, however, the chronic human health 
effects finding was based on chronic neurotoxic effects, instead of 
chronic respiratory effects as stated in the proposed rule.
    After the final rule was issued adding hydrogen sulfide to the 
EPCRA section 313 list, and notwithstanding the fact

[[Page 64026]]

that the Agency cited the same acute aquatic toxicity as an 
``environmental effects'' basis for the listing under EPCRA section 
313(d)(2)(C) in both the proposed rule and the final rule, some members 
of the regulated community expressed a concern that the Agency cited 
chronic respiratory effects as a ``chronic human health effects'' basis 
under EPCRA section 313(d)(2)(B) in the proposed rule, but chronic 
neurotoxic effects as a ``chronic human health effects'' basis under 
that same provision in the final rule. In addition, after issuance of 
the final rule, some members of the regulated community expressed 
concern that EPA's decision not to include an exposure analysis in 
deciding to list hydrogen sulfide on the basis of chronic human health 
effects was inconsistent with past Agency practice. As a result of 
these concerns, some commenters threatened to bring legal action 
challenging the final rule.
    In response to the post-promulgation comments and concerns raised 
by some in the regulated community, and notwithstanding the fact that 
the listing decision was appropriate based on the acute aquatic 
toxicity finding alone under EPCRA section 313(d)(2)(C), EPA issued an 
Administrative Stay of the EPCRA section 313 reporting requirements for 
hydrogen sulfide on August 22, 1994 (59 FR 43048) in order to review 
those post-promulgation comments and concerns.
    The stay issued on August 22, 1994 made clear that: ``The effect of 
this stay is to defer reporting on [hydrogen sulfide] while the Agency 
reviews new data and information made available subsequent to the 
promulgation of the final rule'' (59 FR 43048 (Aug. 22, 1994) (emphasis 
added)). As a result, while the subsequent stay deferred reporting 
requirements, the stay did not remove hydrogen sulfide from the EPCRA 
section 313 list or alter that final listing determination, which 
remained in effect as of January 1, 1994. The listing determination was 
never administratively or judicially challenged.
    On February 26, 2010, EPA issued a notice announcing its ``Intent 
to Consider Lifting [the hydrogen sulfide] Administrative Stay; 
Opportunity for Public Comment.'' 75 FR 8889 (hereinafter Intent to 
Lift the Stay). That document stated: ``The purpose of this document is 
to provide the public with the opportunity to comment on EPA's review 
of the currently available data on the human health and environmental 
effects of hydrogen sulfide * * * and EPA's belief that the 
Administrative Stay should be lifted based on that data* * *. In 
addition, this document addresses the concerns raised regarding use of 
exposure analyses.'' Id. at 8891. The Intent to Lift the Stay notice 
clearly explained: ``By this current action, EPA is not revisiting the 
original listing decision, which was accomplished by final rule on 
December 1, 1993. Rather, EPA is merely presenting its rationale for 
why the Administrative Stay of the reporting requirements for hydrogen 
sulfide should be lifted.'' Id. at 8889 (emphasis added).
    a. EPA Statements when Issuing the Stay. Commenters first argue 
that EPA cannot now limit comment to whether or not to lift the stay 
because the Agency stated, when it issued the Administrative Stay in 
1994, that it intended, at some point in the future, to ``seek comment 
on the Agency's initial determination for [hydrogen sulfide].'' 59 FR 
at 43049. Specifically, the Administrative Stay stated:

    [T]he Agency will be issuing a forthcoming Federal Register 
notice which will seek comment on the Agency's initial determination 
for [hydrogen sulfide], * * * procedural issues concerning the 
initial final rule, and generally, comments (and any supporting 
data) on whether the Agency should either propose to delete 
[hydrogen sulfide] or affirm its initial determination and dissolve 
today's Administrative Stay. (59 FR at 43049).

    Hydrogen sulfide was listed under section 313 of EPCRA by final 
rule on December 1, 1993. The stay did not remove hydrogen sulfide from 
the EPCRA section 313 list or alter that final listing determination. 
The 1993 listing decision was appropriate based on the acute aquatic 
toxicity finding alone under EPCRA section 313(d)(2)(C), which was 
included in both the proposed and final rules and never questioned. 
Therefore, EPA does not believe it is necessary or appropriate to 
revisit the 1993 final listing of hydrogen sulfide in order to lift the 
stay of reporting requirements.
    Further, the Agency believes that its action in taking comment on 
its intent to lift the stay is substantially in accord with the course 
of action it described in issuing the stay in 1994. In the Intent to 
Lift the Stay notice, the Agency discussed and invited comment on the 
data underlying its consideration of the matter and EPA's application 
of its policy regarding exposure assessment to the listing decision. As 
described in the Intent to Lift the Stay notice, EPA's planned course 
of action arises out of EPA's review of the currently available data, 
which clearly demonstrate both chronic health effects in humans (upper 
respiratory tract toxicity and neurotoxicity) and significant adverse 
effects in aquatic organisms (acute, chronic, and early life stage). 
Further, EPA's consideration of these effects is fully consistent with 
its policy on exposure assessment. Based on these findings, EPA 
believes that there is no basis for continuing the Administrative Stay 
of the reporting requirements for hydrogen sulfide, and that the 
Administrative Stay should therefore be lifted.
    Moreover, these findings also demonstrate that there is no basis to 
consider delisting hydrogen sulfide. EPCRA section 313(d)(3) states 
that to remove a chemical from the list, EPA must determine that 
``there is not sufficient evidence to establish any'' of the Section 
313(d)(2) criteria (emphasis added). Therefore, to remove a chemical, 
EPA must demonstrate that none of the criteria are met. As EPA's review 
of the currently available data in the context of its consideration of 
lifting the Administrative Stay demonstrates, EPA cannot show that none 
of the criteria are met. Indeed, the Agency believes that the only 
course available is to dissolve the stay, which it is doing through 
notice-and-comment, and which is substantially in accord with at least 
one of the alternative courses anticipated in 1994.
    Finally, to the extent that the commenters are suggesting that EPA 
is legally prohibited from now limiting comment to the issue of whether 
or not to lift the Administrative Stay based on the statements in the 
preamble the Agency made (excerpted above) when issuing the 
Administrative Stay, EPA respectfully notes that these preamble 
statements do not create such a legal obligation. See, e.g., Natural 
Resources Defense Council v. EPA, 559 F.3d 561, 564-65 (D.C. Cir. 
2009).
    b. Proposed and Final Chronic Human Health Effects. Second, 
commenters argue that EPA cannot now limit comment to whether or not to 
lift the stay because EPA cited chronic respiratory effects as one of 
the bases for listing under EPCRA section 313(d)(2)(B) in the proposed 
rule, but chronic neurotoxic effects as a basis under that same 
provision in the final rule.
    EPCRA section 313(d) authorizes EPA to add or delete chemicals from 
the list and sets forth criteria for these actions. The EPCRA section 
313(d)(2) criteria are:

    (A) The chemical is known to cause or can reasonably be 
anticipated to cause significant adverse acute human health effects 
at concentration levels that are reasonably likely to exist beyond 
facility site boundaries as a result of continuous, or frequently 
recurring, releases.

[[Page 64027]]

    (B) The chemical is known to cause or can reasonably be 
anticipated to cause in humans--
    (i) Cancer or teratogenic effects, or
    (ii) Serious or irreversible--
    (I) Reproductive dysfunctions,
    (II) Neurological disorders,
    (III) Heritable genetic mutations, or
    (IV) Other chronic health effects.
    (C) The chemical is known to cause or can be reasonably 
anticipated to cause, because of
    (i) Its toxicity,
    (ii) Its toxicity and persistence in the environment, or
    (iii) Its toxicity and tendency to bioaccumulate in the 
environment,

a significant adverse effect on the environment of sufficient 
seriousness, in the judgment of the Administrator, to warrant 
reporting under this section.

    EPA often refers to the section 313(d)(2)(A) criterion as the 
``acute human health effects criterion;'' the section 313(d)(2)(B) 
criterion as the ``chronic human health effects criterion;'' and the 
section 313(d)(2)(C) criterion as the ``environmental effects 
criterion.''
    While it is true that the Agency cited chronic respiratory effects 
as a ``chronic human health effects'' basis under EPCRA section 
313(d)(2)(B) in the proposed rule, but chronic neurotoxic effects as a 
``chronic human health effects'' basis under that same provision in the 
final rule, it bears emphasizing once again that the Agency also 
separately cited the same acute aquatic toxicity as an ``environmental 
effects'' basis for the listing under EPCRA section 313(d)(2)(C) in 
both the proposed and final rules. As a result, and in light of the 
fact that EPCRA section 313(d)(2) expressly allows EPA to add a 
chemical to the list if ``there is sufficient evidence to establish any 
one'' of the listing criteria (emphasis added), the 1993 listing 
decision was appropriate based on the acute aquatic toxicity finding 
alone under EPCRA section 313(d)(2)(C). That basis for the listing was 
never questioned and was and continues to be supported by the data 
relied upon by EPA in determining that the stay should be lifted. Any 
procedural error that may have occurred regarding the section 
313(d)(2)(B) ``chronic human health effects'' finding was harmless in 
light of the unchallenged section 313(d)(2)(C) ``environmental 
effects'' finding presented in both the proposed and final rules. This 
analysis also played directly into EPA's decision to proceed in the 
manner it has, as opposed to rigidly following its stated intentions in 
1994.
    EPA is currently lifting the stay of hydrogen sulfide reporting 
requirements--a substance that has been and remains listed under EPCRA 
since promulgation of the final rule on December 1, 1993--based on 
EPA's review of the currently available data, which clearly demonstrate 
both chronic health effects in humans (upper respiratory tract toxicity 
and neurotoxicity) and significant adverse effects in aquatic organisms 
(acute, chronic, and early life stage). EPA is not revisiting the 
original listing determination, and comments on the original listing 
decision are beyond the scope of this action.
    c. EPA's Exposure Analysis Policy. Third, commenters argue that EPA 
cannot now limit comment to whether or not to lift the stay because EPA 
adopted its current policy regarding exposure analysis subsequent to 
the 1993 listing of hydrogen sulfide.
    EPA did not ``adopt a new policy'' on its use of exposure analysis 
for listing chemicals under EPCRA section 313 subsequent to the listing 
of hydrogen sulfide in 1993. Instead, the Agency's then-existing 
position on the use of exposure analyses in listing decisions under 
EPCRA section 313 was presented in a proposed rule in the Federal 
Register of January 12, 1994 (59 FR 1788). That proposed rule provided 
the public with the opportunity to comment on the Agency's then-
existing interpretation of the statutory listing criteria as it relates 
to the use of exposure considerations. After considering the comments 
received, EPA published in the Federal Register of November 30, 1994 
(59 FR 61432) a ``chemical expansion'' final rule, including a 
statement clarifying its interpretation of the statutory requirements 
regarding how exposure is considered in listing decisions. Subsequent 
to that final rule, EPA's interpretation of the statutory listing 
criteria as it relates to the consideration of exposure was upheld in 
National Oilseed Processors Ass'n. v. Browner, 924 F. Supp. 1193 
(D.D.C. 1996), aff'd in part & remanded in part, Troy Corp. v. Browner, 
120 F.3d 277 (D.C. Cir. 1997).
    As stated in the chemical expansion final rule:

    Through this rulemaking, EPA is clarifying its position 
regarding the use of hazard, exposure, and risk in listing decisions 
under EPCRA section 313. EPA will consider exposure factors when 
making determinations under section 313(d)(2)(A) (acute human 
toxicity). In addition, EPA has discretion to consider exposure 
factors where appropriate for determinations under sections 
313(d)(2)(B) (chronic human toxicity) and (C) (environmental 
toxicity), and that there is a broader range of circumstances in 
which exposure will be considered under section 313(d)(2)(C) than 
under (B).
    EPA has reviewed its past listing decisions in light of this 
clarification, and believes that its prior listing determinations 
have been consistent in the consideration of exposure in 31 of the 
32 listing/delisting determinations previous to this action* * *(59 
FR 61442 (Nov. 30, 1994) (emphasis added)).

    In Troy Corp. v. Browner, the DC Circuit agreed with EPA, finding:

    Were the EPA to abandon a long-held exposure policy and take a 
new direction we would, as urged, require a thorough explanation of 
its reasons for doing so. Yet, the EPA's pronouncement in its 
preamble of its exposure policy is not a change in course. With one 
exception, the EPA has consistently stated, as it does in this 
rulemaking, that it will consider exposure under subsection (B) only 
when the chemical was of ``low to moderately low'' toxicity. * * * 
[T]he agency has long maintained that it would consider exposure 
under subheading (B) only for low toxicity chemicals. The inorganic 
fluorides petition was denied over ten years ago. Since that time, 
the agency has made several dozen listing and delisting decisions 
under EPCRA. The inorganic fluorides case was the only instance in 
which the agency articulated a policy contrary to the one explicated 
in this rulemaking. Under these circumstances we cannot say that the 
agency has departed from prior practice in a way that requires more 
explanation than was provided. (Troy Corp. v. Browner, 120 F.3d at 
287 (emphasis added) (citation omitted)).

    Thus, EPA did not subsequently adopt a new exposure policy as 
Commenters suggest. Rather, the Agency simply clarified the existing 
exposure policy. Further, the 31 of 32 previous cases, noted by the 
court in Troy Corp., in which the Agency had been consistent with this 
exposure policy included the listing of hydrogen sulfide. Therefore, 
EPA had applied this same exposure policy to the listing of hydrogen 
sulfide, and need not, as Commenters suggest, provide a new notice and 
opportunity to comment on the use of exposure analyses in listing 
hydrogen sulfide under section 313 of EPCRA.
    As EPA explained in the Intent to Lift the Stay:

    EPA has determined that hydrogen sulfide can reasonably be 
anticipated to cause serious or irreversible chronic human health 
effects at relatively low doses and thus is considered to have 
moderately high to high chronic toxicity. EPA does not believe that 
it is appropriate to consider exposure for chemicals that are 
moderately high to highly toxic based on a hazard assessment when 
determining if a chemical can be listed for chronic effects pursuant 
to EPCRA section 313(d)(2)(B) (see 59 FR 61432, 61433, 61440-61442). 
Hydrogen sulfide has also been determined to cause ecotoxicity at 
relatively low concentrations, and thus is considered to have high 
ecotoxicity. EPA believes that

[[Page 64028]]

chemicals that induce death or serious adverse effects in aquatic 
organisms at relatively low concentrations (i.e., they have high 
ecotoxicity) have the potential to cause significant changes in the 
population of fish and other aquatic organisms, and can therefore 
reasonably be anticipated to cause a significant adverse effect on 
the environment of sufficient seriousness to warrant reporting. EPA 
does not believe that it is required to consider exposure for 
chemicals that have high ecotoxicity based on a hazard assessment 
when determining if a chemical can be listed for effects pursuant to 
EPCRA section 313(d)(2)(C) (see 59 FR 61432, 61433, 61440-61442). 
(75 FR 8889, 8893 (Feb. 26, 2010)).

    d. EPA Must Make a New Listing Determination. Finally, Commenters 
argue that EPA cannot now limit comment to whether or not to lift the 
stay because EPA ``must make a new listing determination before it may 
lift [the stay].''
    This argument merely restates Commenters' first three arguments in 
support of Commenters' ultimate position that EPA must revisit the 1993 
listing decision. For the reasons already discussed above, the Agency 
disagrees with Commenters' arguments.
    2. Implementation of EPA's Exposure Policy. Commenters state that 
EPA may not implement its policy on the use of exposure analysis in 
EPCRA section 313 listing decisions in an arbitrary manner. Commenters 
claim that EPA has not identified the specific criteria it utilizes in 
determining whether a substance causes chronic human health effects at 
relatively low doses or ecotoxicity at relatively low concentrations. 
Commenters noted that EPA stated in its intent to lift the 
Administrative Stay that it is applying the interpretation of the 
statutory listing criteria and the policy on the use of exposure 
analyses adopted by the EPA in its November 30, 1994, final rule 
listing other substances. Commenters cited EPA's statements from the 
rule that exposure considerations are appropriate in making listing 
determinations under EPCRA section 313(d)(2)(B) for chemicals with low 
to moderately low toxicity based on hazard assessment and under EPCRA 
section 313(d)(2)(C) for chemicals that are low or moderately ecotoxic. 
Commenters claim that they were unable to identify or locate in the 
docket for this action any objective criteria that EPA uses in making a 
determination of whether a substance may cause ``serious or 
irreversible chronic health effects'' or has ``low to moderately low 
toxicity.'' Commenters state that they were unable to find any 
explanation of the criteria that EPA uses in deciding whether a 
substance has ``low to moderately low ecotoxicity.'' Commenters noted 
that EPA stated that its interpretation of the statutory listing 
criteria that supports the 1994 policy statement was sustained during 
subsequent judicial review.
    Commenters state that even if EPA has discretion to select a policy 
concerning the circumstances in which exposure analysis will be part of 
the EPCRA section 313(d)(2) listing decision, it does not mean the EPA 
has unfettered discretion to apply that policy in an arbitrary manner. 
Commenters state that if EPA is to have a rational policy that can be 
applied in a fair and equitable manner, the scientists conducting a 
hazard assessment under EPCRA section 313(d)(2) should not be permitted 
to make qualitative judgments concerning potential toxicity in the 
absence of objective criteria or guidance concerning what these terms 
mean. However, as discussed below, this is precisely the question at 
issue in National Oilseed Processors Ass'n. v. Browner, 924 F. Supp. 
1193 (D.D.C. 1996), aff'd in part & remanded in part, Troy Corp. v. 
Browner, 120 F.3d 277 (D.C. Cir. 1997), where those Courts held that 
EPA's exposure analysis policy, including the determination of when a 
toxic chemical has ``moderately high to high toxicity'' based on 
adverse effects at ``low'' or ``moderate'' dose levels and thus does 
not require an exposure analysis in order to be listed, was not 
arbitrary or capricious.
    EPA has identified the criteria that it uses in making a 
determination of whether a substance that may cause ``serious or 
irreversible chronic health effects'' has ``low to moderately low 
toxicity,'' and has not applied its policy on the use of exposure 
analysis in EPCRA section 313 listing determinations in an arbitrary 
manner. To the contrary, in the preamble to the 1994 chemical expansion 
final rule, EPA explained that two types of chemicals are considered to 
exhibit moderately high to high toxicity:
     Where a review of the scientific data provides a high 
level of confidence that the chemical causes an adverse effect at 
relatively low dose levels, and
     Where a review of the scientific data indicates that the 
chemical will cause various adverse effects at moderate dose levels.

(59 FR 61432, 61433 (Nov. 30, 1994).
    Thus, EPA has in fact articulated criteria for its determination 
whether or not exposure considerations will be taken into account in 
its chemical listing decisions.

    More specifically, EPA has provided guidance concerning how it 
evaluates chemicals to determine whether they meet the EPCRA section 
313 listing criteria, including information on the factors EPA 
considers in determining whether a chemical is sufficiently toxic that 
exposure need not be considered in the listing decision. The specific 
criteria EPA uses to determine whether a chemical has moderately high 
or high toxicity, and thus does not have low to moderately low 
toxicity, were explained in detail in the 1994 chemical expansion rule:

    3. Hazard evaluation. After completing the screening phase, EPA 
conducted a thorough hazard assessment for each of the addition 
candidates that resulted from the above analyses and determined 
based on the weight-of-the evidence if there was sufficient evidence 
to establish that the candidate chemical met the statutory criteria 
for addition to EPCRA section 313. To make this determination, EPA 
senior scientists reviewed readily available toxicity information on 
each chemical for each of the following effect areas: acute human 
health effects; cancer; other chronic human effects; and 
environmental effects. In addition, EPA reviewed, where appropriate, 
information on the environmental fate of the chemical.
    The hazard assessment was conducted in accordance with relevant 
EPA guidelines for each adverse human health or environmental effect 
(e.g., the appropriate guidelines for hazard evaluation of chemical 
carcinogens and for the type of evidence required to substantiate a 
determination of carcinogenicity are the Assessment Guidelines for 
Carcinogen Risk (Ref. 4)). During this assessment the number, 
severity, and significance of the effects induced by the chemical, 
the dose level causing the effect, and the quality and quantity of 
the available data, including the nature of the data (e.g., human 
epidemiological, laboratory animal, field or workplace studies) and 
confidence level in the existing data base, were all considered. 
Where a careful review of the scientific data for a particular 
chemical results in a high level of confidence that the chemical 
causes an adverse effect at relatively low dose levels, EPA believes 
that this evidence is sufficient for listing the chemical under 
section 313. EPA also believes that where a review of the scientific 
data indicates that the chemical will cause various adverse effects 
at moderate dose levels, the total weight-of-the-evidence indicates 
that there is sufficient evidence for listing the chemical under 
EPCRA section 313. EPA believes that both types of chemicals 
described above exhibit moderately high to high toxicity based on a 
hazard assessment.
    EPA also conducted an analysis of exposure for each chemical or 
chemical category proposed for listing under EPCRA section 
313(d)(2)(A) (i.e., based on adverse acute human health effects), 
and, where appropriate, under section 313(d)(2)(C) (i.e., based on 
adverse ecological effects). For chemicals listed under EPCRA 
section 313(d)(2)(A), this analysis included estimated 
concentrations of the chemical at or beyond

[[Page 64029]]

the facility site boundary through the use of estimated releases and 
modeling techniques. EPA did not conduct an analysis of exposure for 
the chemicals proposed for listing under section 313(d)(2)(B) 
because these chemicals exhibit moderately high to high toxicity 
based on a hazard assessment (see Unit IV.B. for a discussion of the 
use of exposure). As discussed more thoroughly in Unit IV.B. of this 
preamble, EPA does not believe that it is appropriate to factor 
exposure into the listing decisions for the chemicals being listed 
pursuant to section 313(d)(2)(B) in this rulemaking.
    Following a review and analysis of the information available 
about each chemical in this final rule (including information 
provided through public comment) by senior Agency scientists, the 
Agency concludes that for each of the chemicals listed one or more 
of the EPCRA section 313 listing criteria are met. Moreover, the 
adverse effects associated with each of the chemicals being listed 
today are serious and significant. In some cases the effects are 
extreme, such as cancer or death. In others, the effects are serious 
and lasting, including, for example, impairment of a fetus' or an 
offspring's physical development, neurological effects inhibiting 
motor abilities or mental processes or impairing the ability to 
reproduce, or the sustainability of a fragile ecosystem such as an 
estuary. For a number of chemicals in the final rule, there is more 
than one adverse effect.
    It is important to understand that although an adverse effect is 
known or can be reasonably anticipated to be caused by a chemical on 
the section 313 list, a release of a chemical into a community does 
not necessarily mean that the effect will occur. Exposure and dose 
are also important factors in determining whether an adverse effect 
occurs and how serious the manifestation will be. The listing of a 
chemical on the section 313 list does not mean that a particular 
community will experience these adverse effects. Instead the purpose 
for listing a chemical is to ensure that the public gets information 
about releases of such chemicals. Thus, EPA believes that for 
chemicals that typically do not affect solely one or two species but 
rather affect changes across a whole ecosystem and for which there 
is well-documented evidence supporting the adverse effects, that 
their addition to the EPCRA section 313 list is warranted even 
though the severity of the adverse effects that they induce will be 
dependent upon site-specific characteristics. Once EPA makes release 
data available through TRI, the community may then make its own 
determination on the importance of these releases (and their 
potential adverse effects). (59 FR at 61433, 11/30/1994 (emphasis 
added)).

EPA went on to state in the chemical expansion rule that:

    Through this rulemaking, EPA is clarifying its position 
regarding the use of hazard, exposure, and risk in listing decisions 
under EPCRA section 313. EPA will consider exposure factors when 
making determinations under section 313(d)(2)(A) (acute human 
toxicity). In addition, EPA has discretion to consider exposure 
factors where appropriate for determinations under sections 
313(d)(2)(B) (chronic human toxicity) and (C) (environmental 
toxicity), and that there is a broader range of circumstances in 
which exposure will be considered under section 313(d)(2)(C) than 
under (B).
    EPA has reviewed its past listing decisions in light of this 
clarification, and believes that its prior listing determinations 
have been consistent in the consideration of exposure in 31 of the 
32 listing/delisting determinations previous to this action, 
including a number of deletions of low toxicity chemicals that 
Congress placed on the initial EPCRA section 313 list. EPA is 
currently reviewing the one exception, inorganic fluorides, to 
determine if additional action is warranted. EPA will continue to 
evaluate petitions according to this clarification and will delete 
chemicals that do not meet the statutory criteria. (59 FR at 61442, 
11/30/1994).

    EPA's exposure analysis policy, as set forth in the chemical 
expansion Final Rule, was judicially challenged in National Oilseed 
Producers Ass'n v. Browner, 924 F. Supp. 1193 (D.D.C. 1996). There, the 
plaintiffs presented precisely the same argument that the Hydrogen 
Sulfide Consortium now raises. In National Oilseed, the court stated 
that ``Plaintiffs * * * claim that EPA has not adequately explained 
when it will consider exposure under Section 313(d)(2)(B).'' National 
Oilseed, 924 F. Supp. at 1203. The court squarely rejected that 
argument, holding:

    The Agency argues generally that, in the exercise of its 
discretion, it has elected to consider exposure only in limited 
circumstances. Specifically, when EPA's hazard assessment shows that 
a chemical exhibits only low or moderately low toxicity, EPA will 
consider the potential for exposure in making a listing decision. 
Conversely, where EPA's hazard assessment reveals that a chemical's 
toxicity is high or moderately high, EPA does not consider exposure, 
and will list the chemical based solely on its toxic effect.
* * * * *
    Moreover, EPA asserts that it explained adequately on the record 
that it chose to not consider exposure in this rulemaking because 
all of the chemicals proposed for listing under Section 313(d)(2)(B) 
were of ``high to moderately-high'' toxicity and therefore 
consideration of exposure was not appropriate.
    After consideration of the extensive arguments on both sides of 
this issue, the Court concludes that the Agency did not act 
arbitrarily and capriciously in declining to consider exposure in 
the listing decisions for this rulemaking. * * * While a more 
clearly and fully articulated policy would be preferable, the Court 
cannot conclude that EPA was unreasonable in exercising its 
discretion by continuing to exclude consideration of exposure when 
chemicals are of high to moderately-high toxicity.
* * * * *
    What is significant is that EPA stated what its policy for 
consideration of exposure would be, and then described its 
application to the chemicals considered in this rulemaking.
    Because EPA's decision to not consider exposure in this 
rulemaking was consistent with its policy of using exposure data 
only in particular circumstances, i.e., where chemicals are of low 
toxicity, the Court concludes that the Agency was not arbitrary and 
capricious.

    National Oilseed, 924 F. Supp. at 1203-04 (citations and footnotes 
omitted).

    On appeal to the U.S. Court of Appeals for the D.C. Circuit, the 
plaintiffs again raised this same argument. There, the court stated: 
``* * * [Plaintiffs] argue that the EPA abused its discretion and acted 
arbitrarily and capriciously by failing to establish criteria for the 
consideration of exposure * * *.'' Troy Corp. v. Browner, 120 F.3d 277, 
282 (D.C. Cir. 1997). On this point, the D.C. Circuit rejected the 
plaintiffs' argument and affirmed the judgment of the D.C. District 
Court in National Oilseed. Troy Corp., 120 F.3d at 293.
    Just as EPA did in the 1994 chemical expansion rule and other 
previous listing decisions, upheld by the Courts in National Oilseed 
and Troy Corp.--including application of the Agency's exposure analysis 
policy in conducting such hazard assessments--EPA conducted a hazard 
assessment of the human health and ecological effects of hydrogen 
sulfide, upon which the determinations that hydrogen sulfide has 
moderately high to high human toxicity were based. Based on the data 
from the hazard assessment, as presented in the Federal Register notice 
and supporting documents, EPA determined that hydrogen sulfide has 
moderately high to high toxicity to humans and is highly toxic to 
aquatic organisms. EPA discussed these determinations in detail in the 
notice of Intent to Lift the Stay in the Federal Register (75 FR 8889, 
2/26/2010). Human health toxicity was discussed in detail beginning on 
page 8891, with references, and ecological effects were discussed in 
detail beginning on page 8893, with references.
    In the section of the Federal Register document that discussed the 
rationale for lifting the stay, EPA provided the following summary of 
the hazard data:

    EPA's technical evaluation of hydrogen sulfide shows that it can 
reasonably be anticipated to cause chronic health effects in humans. 
The chronic health effects have been observed in laboratory animals 
at concentrations as low as 28 mg/m\3\ (20 ppm) and 41.7 mg/m\3\ (30 
ppm). In addition, EPA's technical evaluation of hydrogen sulfide 
also shows that it can reasonably be anticipated

[[Page 64030]]

to cause, because of its toxicity, significant adverse effects in 
aquatic organisms. Examples of hydrogen sulfide's ecological 
toxicity include acute toxicity (96-hour LC50) values for 
freshwater fish that ranged from 0.0149 mg/L (fathead minnow) to 
0.0448 mg/L (bluegill), indicating high aquatic toxicity. Examples 
of hydrogen sulfide's chronic ecological toxicity include freshwater 
fish values that ranged from a 6-week LOEC (growth rate) of 0.0005 
mg/L in a tropical fish (Mystus nemurus) to a 430-day LOEC (final 
weight) of 0.009 mg/L for goldfish, also indicating high aquatic 
toxicity. (75 FR 8893, 2/26/2010).

    As the language above clearly shows, EPA did identify the 
information and the rationale for why hydrogen sulfide was determined 
to have moderately high to high human toxicity and high ecotoxicity.
    3. EPA's Rationale for Hydrogen Sulfide's Toxicity Level. 
Commenters claim that EPA has not given its rationale for why hydrogen 
sulfide causes chronic human health effects at relatively low levels 
and ecotoxicity at relatively low concentrations. Commenters contend 
that EPA has not provided any rationale for the determinations that no 
exposure assessment is needed for hydrogen sulfide. Commenters noted 
that EPA provided a description of the chronic human health effects and 
ecological toxicity of hydrogen sulfide. Commenters also noted that EPA 
asserted that it had made the requisite determinations concerning the 
relative magnitude of the toxicity of hydrogen sulfide for both human 
health and ecological effects. Commenters contend, however, that EPA's 
statements are wholly conclusory and that the docket does not appear to 
contain any explanations of the relation between the hazard assessments 
prepared by EPA scientists and these determinations. Commenters state 
that they do not believe that the effect levels cited by EPA will be 
caused by the releases reportable under EPCRA section 313. Commenters 
state that they believe that the effect levels cited by EPA as 
``relatively low'' are actually very high. Commenters stated that the 
chronic health effect levels cited by EPA are 2,000 to 3,000 times 
greater than the odor detection threshold (10 parts per billion (ppb)) 
for hydrogen sulfide. Commenters claim that while releases may result 
in ambient hydrogen sulfide concentrations that exceed the odor 
detection threshold, the concentrations will always be far below the 
lowest levels for chronic effects in animals cited by EPA. Commenters 
cited a 1990 EPA study on oil and natural gas extraction and a 1999 
Public Health Service study for one city near hydrogen sulfide sources 
as evidence that hydrogen sulfide levels are low. Commenters also cited 
established state air standards that range from 83 to 200 ppb noting 
that these are 100 to 150 times less than the lowest levels EPA cited 
for chronic effects in animals.
    In discussing the data EPA cited as supporting its evaluation that 
hydrogen sulfide is toxic to aquatic organisms at relatively low 
concentrations, the commenters stated that while the levels may seem 
relatively low in the abstract, they believe they are actually quite 
high when viewed in the context of data that clearly establish that 
hydrogen sulfide will rapidly oxidize to less toxic chemical forms when 
released to surface waters. Commenters cited the EPA Water Quality 
Criteria Gold Book as support for their position:

    The fact that H2S is oxidized in well-aerated water 
by natural biological systems to sulfates or is biologically 
oxidized to elemental sulfur has caused investigators to minimize 
the toxic effects of H2S on fish and other aquatic life. 
(EPA Gold Book, May 1, 1986, page 268 (Ref. 2)).

    As discussed in the previous response, EPA has provided guidance on 
how it determines whether a chemical has moderately high to high human 
toxicity and high ecotoxicity. In its notice of Intent to Lift the 
Stay, EPA provided a detailed hazard assessment of both the human 
health effects and the ecological effects of hydrogen sulfide. This 
assessment included both the effects caused by hydrogen sulfide and the 
doses/concentrations that caused those effects. This information was 
discussed in the Federal Register (75 FR 8889, 2/26/2010), and the 
details were contained in the hazard assessments and other references 
cited by EPA. Specifically, at 75 FR 8889, 8891-8893 (Feb. 26, 2010), 
EPA's lengthy and detailed technical review of hydrogen sulfide (Part 
IV. of the Federal Register notice, entitled ``What is EPA's Technical 
Review of Hydrogen Sulfide?''), including references, can be found (and 
need not be reiterated here). EPA then concluded, based on the hazard 
assessment:

    EPA has determined that hydrogen sulfide can reasonably be 
anticipated to cause serious or irreversible chronic human health 
effects at relatively low doses and thus is considered to have 
moderately high to high chronic toxicity * * *. Hydrogen sulfide has 
also been determined to cause ecotoxicity at relatively low 
concentrations, and thus is considered to have high ecotoxicity. EPA 
believes that chemicals that induce death or serious adverse effects 
in aquatic organisms at relatively low concentrations (i.e., they 
have high ecotoxicity) have the potential to cause significant 
changes in the population of fish and other aquatic organisms, and 
can therefore reasonably be anticipated to cause a significant 
adverse effect on the environment of sufficient seriousness to 
warrant reporting. (75 FR 8893, 2/26/2010).

    In the section of the Federal Register document that discussed the 
rationale for lifting the stay, EPA provided the following summary of 
the hazard data:

    EPA's technical evaluation of hydrogen sulfide shows that it can 
reasonably be anticipated to cause chronic health effects in humans. 
The chronic health effects have been observed in laboratory animals 
at concentrations as low as 28 mg/m\3\ (20 ppm) and 41.7 mg/m\3\ (30 
ppm). In addition, EPA's technical evaluation of hydrogen sulfide 
also shows that it can reasonably be anticipated to cause, because 
of its toxicity, significant adverse effects in aquatic organisms. 
Examples of hydrogen sulfide's ecological toxicity include acute 
toxicity (96-hour LC50) values for freshwater fish that 
ranged from 0.0149 mg/L (fathead minnow) to 0.0448 mg/L (bluegill), 
indicating high aquatic toxicity. Examples of hydrogen sulfide's 
chronic ecological toxicity include freshwater fish values that 
ranged from a 6-week LOEC (growth rate) of 0.0005 mg/L in a tropical 
fish (Mystus nemurus) to a 430-day LOEC (final weight) of 0.009 mg/L 
for goldfish, also indicating high aquatic toxicity. (75 FR 8893, 2/
26/2010).

    The above determinations are based on the human health effects and 
ecological effects caused by hydrogen sulfide and the doses/
concentrations that caused those effects. EPA clearly stated why the 
hazard assessment supports a finding of moderately high to high human 
toxicity and high ecotoxicity. Therefore, EPA has clearly stated how 
the hazard assessment data supports a conclusion that hydrogen sulfide 
has moderately high to high human toxicity and high ecological 
toxicity.
    Regarding the information that the commenter provided on previous 
exposure assessments, air standards, etc., none of that information is 
relevant to a determination that hydrogen sulfide has moderately high 
to high human toxicity or high ecological toxicity. The toxicity of a 
chemical is separate from whether there are exposures from facility 
releases of that chemical or not. In addition, the information provided 
by the commenter does not demonstrate that releases of hydrogen sulfide 
could not reach a level of concern from all the types of facilities 
that report under EPCRA section 313. EPA notes that the examples of the 
very low air standards for hydrogen sulfide of 83-200 parts per billion 
support EPA's determination that hydrogen sulfide is highly toxic.
    The commenter's statement that the cited toxic effects of hydrogen 
sulfide are 2,000 to 3,000 times greater than the odor detection 
threshold for hydrogen

[[Page 64031]]

sulfide of 10 ppb is not a basis for discounting the toxic effects of 
hydrogen sulfide. As EPA has stated:

    Recent reviews of the health hazards associated with 
H2S exposure and subsequent treatment include Milby and 
Baselt (1999a) and Guidotti (1996). Earlier reviews of the health 
effects were provided by Glass (1990), Reiffenstein et al. (1992), 
and Mehlman (1994). Exposure to H2S has been reported to 
be an important cause of morbidity and mortality in the workplace 
(Snyder et al., 1995) and olfactory dysfunction (Hirsch and Zavala, 
1999). These reviews indicate that the typical ``rotten-egg odor'' 
of H2S is an inadequate warning indicator of exposure 
since levels in the range of 100-200 ppm (140-280 mg/m\3\) can lead 
to loss of smell followed by olfactory paralysis (Reiffenstein et 
al., 1992) (IRIS, 2003, page 10 (Ref. 3)).

    In addition, simply because someone can smell hydrogen sulfide does 
not mean they will automatically remove themselves from that exposure. 
Individuals that are frequently exposed to hydrogen sulfide may become 
less sensitive to the smell and, as indicated in the IRIS assessment, 
it is possible to have loss of smell from hydrogen sulfide exposure.
    Commenters further state that:

    EPA bases its evaluation that H2S is ecotoxic at 
``relatively low concentrations'' exclusively on potential effects 
on aquatic life, noting that toxicity values for aquatic species 
include ``numerous values that are well below 1 milligram per liter 
(mg/L).'' While the levels cited by EPA may seem ``relatively low'' 
in the abstract, they are actually quite high when viewed in the 
context of data that clearly establish that H2S will be 
rapidly oxidized to less toxic chemical forms when released to 
surface waters. The EPA Water Quality Criteria Gold Book makes a 
similar observation:
    The fact that H2S is oxidized in well-aerated water 
by natural biological systems to sulfates or is biologically 
oxidized to elemental sulfur has caused investigators to minimize 
the toxic effects of H2S on fish and other aquatic life.
    (Footnotes omitted)

    The quote from the water quality criteria document that ``[t]he 
fact that H2S is oxidized in well-aerated water by natural 
biological systems to sulfates or is biologically oxidized to elemental 
sulfur has caused investigators to minimize the toxic effects of 
H2S on fish and other aquatic life'' is from the 
introductory paragraph of the water quality criteria for hydrogen 
sulfide. This statement simply explains what has caused some 
investigators in the past to minimize the toxic effects of hydrogen 
sulfide. However, in the rationale section, the document goes on to 
discuss the toxicity of hydrogen sulfide to aquatic life in detail and 
does not dismiss the potential impacts hydrogen sulfide may have on 
aquatic life. In fact, the document presents the rationale for setting 
a water quality criterion of just 2 micrograms per liter ([mu]g/L) 
undissociated hydrogen sulfide for fish and other aquatic life in both 
fresh and marine water. Concerning oxidation, the EPA Gold Book states:

    The degree of hazard exhibited by sulfide to aquatic animal life 
is dependent on the temperature, pH, and dissolved oxygen. At lower 
pH values a greater proportion is in the form of the toxic 
undissociated H2S. In winter when the pH is neutral or 
below or when dissolved oxygen levels are low but not lethal to 
fish, the hazard from sulfide is exacerbated. (EPA Gold Book, May 1, 
1986, page 268, (Ref. 2)).

The criteria document also states that:

    Many past data on the toxicity of hydrogen sulfide to fish and 
other aquatic life have been based on extremely short exposure 
periods. Consequently, these early data have indicated that 
concentrations between 0.3 and 0.4 mg/L permit fish to survive (Van 
Horn 1958, Boon and Follie 1967, Theede et al., 1969). Recent long-
term data, both in field situations and under controlled laboratory 
conditions, demonstrate hydrogen sulfide toxicity at lower 
concentrations. (EPA Gold Book, May 1, 1986, page 268, (Ref. 2)).

and concludes that:

    Available data indicate that water containing concentrations of 
2.0 [mu]g/L undissociated H2S would not be hazardous to 
most fish and other aquatic wildlife, but concentrations in excess 
of 2.0 [mu]g/L would constitute a long-term hazard.'' (EPA Gold 
Book, May 1, 1986, page 270 (emphasis added) (Ref. 2)).

The conclusion that a concentration of hydrogen sulfide in excess of 
just 2.0 [mu]g/L would constitute a long-term hazard to aquatic life 
supports a determination that hydrogen sulfide is clearly highly toxic 
and a potential hazard to aquatic life despite its fate under certain 
environmental conditions. If hydrogen sulfide were not highly toxic to 
fish and other aquatic life, then there would be no need for such a 
very low water quality criteria value.
    Regarding the two references cited by the commenters concerning 
oxidation of hydrogen sulfide in seawater and aqueous solutions (i.e., 
Millero, F.J., Hubinger, Fernandez and Garnett (1987). Oxidation of 
H2S in Seawater as a Function of Temperature, pH and Ionic 
Strength. Env. Sci. Tech. 21:439-443; Obrien, D.J. and Birkner, F.B. 
(1977). Kinetics of Oxygenation of Reduced Sulfur Species in Aqueous 
Solutions. Env. Sci. Tech. 11:1114-1120.), the Millero reference was 
cited in EPA's hazard assessment (page 8) and the Obrien reference was 
cited in the Millero reference (Ref. 4). EPA is thus familiar with the 
issue of oxidation of hydrogen sulfide and discussed the topic in its 
hazard assessment on page 8 and again on page 17 (Ref. 4). However, the 
fact that hydrogen sulfide can be oxidized under certain environmental 
conditions does not mean that it is not highly toxic. As was cited 
above, the EPA Gold Book stated:

    The degree of hazard exhibited by sulfide to aquatic animal life 
is dependent on the temperature, pH, and dissolved oxygen. At lower 
pH values a greater proportion is in the form of the toxic 
undissociated H2S. In winter when the pH is neutral or 
below or when dissolved oxygen levels are low but not lethal to 
fish, the hazard from sulfide is exacerbated. (EPA Gold Book, May 1, 
1986, page 268 (Ref. 2)).

    If hydrogen sulfide were rapidly oxidized to harmless chemicals 
under all environmental conditions, then that would have an impact on 
EPA's assessment, but that is certainly not the case. How much damage a 
particular release of hydrogen sulfide will cause can depend on a 
number of factors including the amount of the release, whether the 
release is continuous or infrequent, the pH of the water, the 
temperature of the water, the type of water (fresh or seawater), the 
time of year, velocity of the body of water, etc. These factors would 
be considered in site-specific exposure and risk assessments. While 
hydrogen sulfide may be oxidized under certain environmental 
conditions, there are many common environmental conditions under which 
oxidation will not be significant and thus will not lessen the impact 
of a release of hydrogen sulfide. As the aquatic toxicity data shows, 
hydrogen sulfide is toxic to many different aquatic species and at 
several stages of life with some toxicity values at or below one part 
in a billion. Thus, it takes very little hydrogen sulfide to have an 
impact on aquatic life. Even under favorable oxidation conditions, the 
experimental half-life of hydrogen sulfide is 50 hours in fresh water 
and 26 hours in seawater. Considering how low the 48 and 96 hour 
LC50 values are for hydrogen sulfide, hydrogen sulfide 
toxicity is still a concern even under favorable oxidation conditions. 
The potential oxidation of hydrogen sulfide does not lessen the 
inherent toxicity of hydrogen sulfide.
    EPA notes that, other than the single quote from the water quality 
criteria document and two references concerning oxidation of hydrogen 
sulfide in water, the commenters have not questioned or tried to refute 
in any way the aquatic toxicity information provided in EPA's hazard 
assessment. The summary table of the aquatic

[[Page 64032]]

toxicity values presented in the hazard assessment provided over 90 
toxicity values from more than a dozen sources. The commenters did not 
provide any specific comments on why those data should not be 
considered sufficient to support EPA's conclusions.
    With regard to the commenters' statements concerning criteria or 
guidance for determining whether a chemical has moderately high to high 
human toxicity or high ecological toxicity, it appears that the 
commenters may have been looking for some type of numerical cutoffs. 
The comments regarding criteria or guidance for determining whether a 
chemical has moderately high to high human toxicity or high ecological 
toxicity have been addressed in EPA's other responses to the 
commenters. With regard to possible numerical cutoffs, EPA does not 
agree that numerical cutoffs should be or need to be established in 
order to determine whether a chemical has moderately high to high human 
toxicity or high ecological toxicity. As EPA explained in the chemical 
expansion rule in 1994:

    The hazard assessment was conducted in accordance with relevant 
EPA guidelines for each adverse human health or environmental effect 
(e.g., the appropriate guidelines for hazard evaluation of chemical 
carcinogens and for the type of evidence required to substantiate a 
determination of carcinogenicity are the Assessment Guidelines for 
Carcinogen Risk (Ref. 4)). During this assessment the number, 
severity, and significance of the effects induced by the chemical, 
the dose level causing the effect, and the quality and quantity of 
the available data, including the nature of the data (e.g., human 
epidemiological, laboratory animal, field or workplace studies) and 
confidence level in the existing data base, were all considered. 
Where a careful review of the scientific data for a particular 
chemical results in a high level of confidence that the chemical 
causes an adverse effect at relatively low dose levels, EPA believes 
that this evidence is sufficient for listing the chemical under 
section 313. EPA also believes that where a review of the scientific 
data indicates that the chemical will cause various adverse effects 
at moderate dose levels, the total weight-of-the-evidence indicates 
that there is sufficient evidence for listing the chemical under 
EPCRA section 313. EPA believes that both types of chemicals 
described above exhibit moderately high to high toxicity based on a 
hazard assessment. (59 FR 61433, 11/30/1994).

    EPA provided a hazard assessment that presented the information 
used to support the finding that hydrogen sulfide has moderately high 
to high human toxicity and high ecotoxicity. As in the 1994 rulemaking, 
and subsequent rulemakings, the data presented in the hazard 
assessments addressed issues such as the number, severity, and 
significance of the effects induced by the chemical, the dose level 
causing the effect, and the quality and quantity of the available data, 
including the nature of the data (e.g., human epidemiological, 
laboratory animal, field or workplace studies) and confidence level in 
the existing data base. All commenters had the opportunity to comment 
on whether these data support EPA's determinations regarding the 
toxicity of hydrogen sulfide in response to EPA's notice of Intent to 
Lift the Stay of the reporting requirements for hydrogen sulfide. 
Establishing a numerical cutoff would limit EPA's ability to consider 
other factors that might increase or decrease the concern for the 
toxicity of a chemical. For example, if one chemical causes one serious 
effect at 100 milligrams per kilogram per day (mg/kg/day) and another 
chemical causes multiple serious effects across multiple organ systems 
but at 300 mg/kg/day it would not make sense to discount the latter if 
there were some arbitrary numerical cutoff of 200 mg/kg/day. EPA does 
not believe that would be the correct way to evaluate chemicals for 
listing. Rather, EPA considers all of the toxicity data, including the 
doses/concentrations causing the toxic effects, in making 
determinations about the toxicity of a chemical. EPA provided this 
information in the hazard assessment for hydrogen sulfide and provided 
its rationale for lifting the stay based on this information.
    While EPA has not set numerical cutoffs, a quick review of the 
chemicals included in the 1994 chemical expansion rule (59 FR 61432, 
11/30/1994), the persistent, bioaccumulative, and toxic (PBT) chemicals 
rule (64 FR 693, 1/5/1999), and other actions shows that the doses and 
concentrations that cause adverse effects for hydrogen sulfide are well 
within those of chemicals that EPA has previously determined to have 
moderately high to high human toxicity and high ecotoxicity. In fact, 
with regard to ecotoxicity, some of the levels at which hydrogen 
sulfide causes toxicity are among the lowest that EPA has evaluated. 
Even if EPA were to establish numerical cutoffs, based on EPA's 
previous listing determinations the levels at which hydrogen sulfide 
causes toxicity would be well below any such numerical cutoffs.
    With regard to the phrase ``relatively low doses,'' this simply 
refers to doses that are low relative to the body burden they impose. 
Dose levels are most often measured as (or converted into) the units 
milligrams per kilogram per day (mg/kg/day) where kilogram refers to 
each kilogram of body weight. As noted above, EPA has explained that in 
determining whether a chemical has moderately high to high chronic 
toxicity the dose levels causing the effects along with the number and 
severity of the adverse effects are considered (59 FR 61433, 1/30/
1994). While EPA has not set a numerical cutoff for a relatively low 
dose, it has provided numerous examples of the dose levels that EPA 
considers to be relatively low as well as dose levels that EPA 
considers to be relatively high. The 1994 chemical expansion rule alone 
contains over 200 examples of relatively low doses (59 FR 1788, 1/12/
1994). Doses in that rule that were considered relatively low were 
generally at or below 100 mg/kg/day. EPA has also identified, through 
numerous actions, dose levels that are considered to be high or 
relatively high. Such dose levels are typically at or above 500 mg/kg/
day, with most examples being in excess of 1,000 mg/kg/day or more (see 
for example: 59 FR 49888, 9/30/1994; 60 FR 46076, 9/5/1995, and 64 FR 
8769, 2/23/1999). Even in the rulemaking that added hydrogen sulfide to 
the TRI list, EPA identified doses of 600 and 1,000 mg/kg/day as 
``relatively high doses'' (57 FR 41020, 9/8/1992). These ``relatively 
high doses'' were cited by EPA in the determinations that b-
chloronapthalene and isobutyl alcohol were not sufficiently toxic to be 
added to the EPCRA section 313 list (57 FR 41033, 9/8/1992). These dose 
levels are significantly higher than the less than 15 mg/kg/day doses 
(converted from 20-30 ppm) that EPA has cited as being relatively low 
for hydrogen sulfide. While EPA has not set a numerical cutoff for 
relatively low doses, the Agency has provided, through the listing and 
delisting of chemicals, substantial guidance for this terminology.
    As EPA has noted, low dose alone is not the only consideration in 
determining whether a chemical has moderately high to high toxicity and 
thus should be listed on hazard alone:

    Where a careful review of the scientific data for a particular 
chemical results in a high level of confidence that the chemical 
causes an adverse effect at relatively low dose levels, EPA believes 
that this evidence is sufficient for listing the chemical under 
section 313. EPA also believes that where a review of the scientific 
data indicates that the chemical will cause various adverse effects 
at moderate dose levels, the total weight-of- the-evidence indicates 
that there is sufficient evidence for listing the chemical under 
EPCRA section 313. EPA believes that both types of chemicals 
described above exhibit moderately high to high toxicity based on a 
hazard assessment. (59 FR 61433, 1/30/1994).


[[Page 64033]]


An example of this concept is the listing of triphenyltin chloride. 
This chemical was cited by EPA as causing significant reproductive 
toxicity, including adverse effects on the testes, epididymis, sperm 
duct, prostate gland, seminal vesicle, Cowper's gland, and accessory 
glands, at an oral dose of 380 mg/kg over 19 days. While the dose level 
was more moderate, EPA determined that the severity and number of 
effects were sufficient for listing (59 FR 1843, 1/12/1994). This is 
the kind of flexibility regarding dose levels that is required when 
making determinations about the toxicity of chemicals, and is 
consistent with the exposure policy EPA has established for EPCRA 
section 313 determinations.
    Regarding the phrase ``relatively low concentrations'' used in the 
assessment of ecological toxicity, this is similar to the ``relatively 
low dose'' terminology in that it focuses on concentrations that result 
in low doses to the organisms. Data for aquatic organisms is the most 
commonly cited data and typically has the units of milligrams per liter 
(mg/L). As EPA has stated, exposure assessments are not used to list a 
chemical for ecological effects if it has high toxicity. Based on 
concentration, EPA has typically limited its consideration of highly 
toxic to those chemicals that cause acute effects at about 1 mg/L or 
less and chronic effects at 0.1 mg/L or less (see for example: 57 FR 
41020, 9/8/1992 and 59 FR 1788, 1/12/1994). Since the statutory 
criteria of EPCRA section 313(d)(2)(C) also includes consideration of 
persistence and bioaccumulation, EPA has considered somewhat higher 
concentrations as highly toxic for chemicals with those characteristics 
(64 FR 696, 1/5/1999). As with chronic human health effects, EPA has 
not set a numerical cut off for relatively low concentrations, but has 
provided, through the listing and delisting of chemicals, substantial 
guidance for this terminology.
    EPA notes that other programs within the Agency that have numerical 
cutoffs for aquatic organisms have set numerical cutoffs that are 
consistent with the kind of toxicity concentrations that EPA has 
identified as being highly toxic in EPCRA section 313 evaluations. For 
example, the Office of Pesticide Programs cites the following:

      Ecotoxicity Categories for Terrestrial and Aquatic Organisms
------------------------------------------------------------------------
         Concentration (ppm)                   Toxicity category
------------------------------------------------------------------------
                        Aquatic Organisms: Acute
------------------------------------------------------------------------
< 0.1...............................  very highly toxic.
0.1-1...............................  highly toxic.
>1-10...............................  moderately toxic.
>10-100.............................  slightly toxic.
> 100...............................  practically nontoxic.
------------------------------------------------------------------------
(http://www.epa.gov/oppefed1/ecorisk_ders/toera_analysis_eco.htm#Ecotox).

Under the above numerical cutoffs, not only would hydrogen sulfide be 
considered highly toxic, but most of the available data would support a 
classification of very highly toxic.
    4. Qualitative Judgment on Exposure Levels. Commenters stated that 
the lack of any objective rationale for EPA's determination that 
hydrogen sulfide causes health and ecological effects at relatively low 
levels suggests that EPA made a qualitative judgment about the 
magnitude of the potential exposure without preparing any supporting 
exposure analysis. Commenters restated their position that EPA has not 
provided any objective criteria for its determination that hydrogen 
sulfide causes human health effects and ecological effects at 
relatively low levels. Commenters assert that one possibility is that 
EPA scientists have simply made a qualitative judgment concerning the 
plausibility that hydrogen sulfide exposure might occur at the levels 
in question. Commenters stated that such a judgment would be 
intrinsically arbitrary when it is possible to do a proper and 
defensible exposure analysis. Commenters claim that if an exposure 
analysis were conducted they are confident it would show that exposure 
levels are below the levels that EPA has identified for human health 
effects and ecological effects.
    As discussed in a previous response to this commenter, EPA has 
provided the information it used to determine that hydrogen sulfide has 
moderately high to high human toxicity and high ecotoxicity and has 
explained the methodology by which EPA makes such determinations. 
Therefore, EPA disagrees with the commenter's statement that EPA did 
not provide an objective rationale for its determinations.
    Commenter asserts that:

    One possibility is that EPA scientists have simply made a 
qualitative judgment concerning the plausibility that H2S 
exposure might occur at the levels in question. Such a judgment 
would be intrinsically arbitrary when it is possible to do a proper 
and defensible exposure analysis.

There is nothing in the materials that EPA has provided that even 
suggests that EPA made a qualitative judgment about hydrogen sulfide 
exposure levels. The determination as to whether or not a chemical has 
moderately high to high human toxicity or high ecotoxicity is separate 
from any consideration of potential exposures. EPA did not consider or 
evaluate the potential exposures to hydrogen sulfide in making its 
finding that hydrogen sulfide has moderately high to high toxicity to 
humans and is highly toxic to aquatic organisms. The toxicity of a 
chemical is an intrinsic property of the chemical that is established 
by determining what exposure level (i.e., dose) causes adverse effects 
through appropriately conducted toxicological studies; it is not based 
on releases that occur at facilities. Consideration of the level of 
exposure from releases occurring at facilities is part of a risk 
assessment, not a hazard assessment. Unlike the intrinsic toxicity of a 
chemical, exposure levels can change depending on many factors such as 
release quantities, type of release, changes in weather patterns, etc. 
As EPA has stated:

    It is important to understand that although an adverse effect is 
known or can be reasonably anticipated to be caused by a chemical on 
the section 313 list, a release of a chemical into a community does 
not necessarily mean that the effect will occur. Exposure and dose 
are also important factors in determining whether an adverse effect 
occurs and how serious the manifestation will be. The listing of a 
chemical on the section 313 list does not mean that a particular 
community will experience these adverse effects. Instead the purpose 
for listing a chemical is to ensure that the public gets information 
about releases of such chemicals. Thus, EPA believes that for 
chemicals that typically do not affect solely one or two species but 
rather affect changes across a whole ecosystem and for which there 
is well-documented evidence supporting the adverse effects, that 
their addition to the EPCRA section 313 list is warranted even 
though the severity of the adverse effects that they induce will be 
dependent upon site-specific characteristics. Once EPA makes release 
data available through TRI, the community may then make its own 
determination on the importance of these releases (and their 
potential adverse effects). (59 FR 61433, 11/30/1994).

    In upholding EPA's interpretation of EPCRA section 313 listing 
decisions as it relates to the use of exposure, the U.S. Court of 
Appeals for the District of Columbia itself provided a very good 
example of the difference between the toxicity of a chemical and 
exposure to that chemical:


[[Page 64034]]


    It is not the case that the congressional language mandating 
listing of a chemical that `is known to cause or can reasonably be 
anticipated to cause in humans' the enumerated adverse effects 
unambiguously incorporates the likelihood of contact between humans 
and the chemical. A simple analogy quickly refutes NPG's argument 
that the language is unambiguous. Consider a herpetologist and a 
student contemplating a reptile imprisoned in a glass cage. The 
student asks, `Can that snake's bite reasonably be anticipated to 
cause death in humans?' The scientist replies, `Yes.' The scientist 
is not commenting on the likelihood of the serpent's escape, only 
the toxicity of its venom. Concededly, his answer could be taken to 
mean, `Yes, it is likely that this creature will escape, bite 
someone, and kill them.' But that is certainly not the unambiguous 
purport of his words. Even so is the statutory language of Congress. 
It is conceivable that Congress may have contemplated release in its 
phrasing of the standard, but that is certainly not unambiguously 
the case. (Troy Corp. v. Browner, 120 F.3d 277, 285 (D.C. Cir. 
1997)).

    The example of a venomous snake in a glass cage provides a perfect 
illustration of the difference between exposure and toxicity. Just as 
the containment of the venomous snake in a glass cage does not change 
the fact that the snake's venom is highly toxic, lack of exposure does 
not lessen the intrinsic toxicity of a chemical. Lack of exposure 
addresses the issue of the level of risk, not the level of toxicity.
    5. Use of Best Available Science. Commenters claim that EPA did not 
properly consider the best available scientific evidence concerning 
hydrogen sulfide toxicity and exposure. Commenters cited one clinical 
study of potential neurological effects of hydrogen sulfide exposure in 
humans that EPA did not consider. Commenters stated that in the 
Fieldler et al. study (Ref. 5), 74 healthy male and female volunteers 
participated in a clinical study designed to evaluate neurobehavioral 
effects of 2-hour controlled chamber exposures to hydrogen sulfide. 
Commenters state that neurobehavioral effects were evaluated using a 
battery of established tests immediately prior to, and immediately 
following, exposure to 0.05, 0.5, and 5.0 ppm hydrogen sulfide in 
separate sessions approximately one week apart. Commenters state that 
the sequence of exposures was randomly assigned to each subject and 
that the investigators reported that no significant changes were found 
between pre- and post-exposure performance, and that no dose-response 
was found in any of the neurobehavioral or neurosensory data sets. 
Commenters contend that although the exposures studied in the Fiedler 
et al. study did not constitute chronic exposure, the study is highly 
relevant in establishing the levels at which humans might experience 
neurological effects from hydrogen sulfide exposure. Commenters claim 
that the neurobehavioral endpoints that were evaluated in this study 
are likely to be much more effective in capturing subtle neurological 
impairments that could not be detected in animal studies.
    Commenters provided an additional primary literature resource for 
the evaluation of hydrogen sulfide human health effects. However, the 
commenters mistakenly reported no significant changes between pre- and 
post-exposure performance. This is inaccurate as the authors identified 
significant impairment of verbal learning in all exposure groups (p <= 
0.0003). Although the response was not dose dependent, the authors 
offer several explanations for this finding including a threshold 
effect for hydrogen sulfide as low as 0.05 ppm.
    EPA's Federal Register notice of Intent to Lift the Stay of the 
hydrogen sulfide reporting requirements specifically states that the 
human health concern for hydrogen sulfide is chronic human health 
effects (both upper respiratory and neurotoxic effects) (75 FR 8893, 
February 26, 2010). As the commenters correctly pointed out, the 
Fiedler et al. study ``Sensory and Cognitive Effects of Acute Exposure 
to Hydrogen Sulfide'' evaluated only acute exposures--not chronic 
exposures. The study evaluated subjects exposed to hydrogen sulfide for 
<=2 hours. Therefore, the study in question is not relevant to the 
chronic human health effects or the environmental effects that form the 
basis of EPA's cited concerns for hydrogen sulfide.
    While the Fiedler et al. study may be relevant in establishing the 
levels at which humans might experience neurological effects from acute 
hydrogen sulfide exposure, the Agency does not support the extension to 
chronic neurological effects. The Fiedler et al. study was designed to 
evaluate cognitive endpoints shown to be responsive in acute studies. 
As detailed in the Federal Register (75 FR 8891, February 26, 2010), 
hydrogen sulfide neurotoxicity is thought to occur due to hypoxia 
induced neuronal cell death. This pathology would not be evidenced in 
the short-term human study conducted by Fiedler et al. because the 
exposures were acute not chronic. Therefore, we would also conclude 
that the neurobehavioral endpoints that were used in the Fiedler et al. 
study are not, as the commenters suggest, ``likely to be much more 
effective in capturing subtle neurological impairments that could not 
be detected in animal studies'' since the effects of chronic exposure 
would not be observed. The ability to sacrifice animals to study 
neurotransmitters and brain chemistry provides information that is not 
available in human studies. These types of studies provide powerful 
quantitative data, as evidenced in Skrajny et al. (Ref. 6).
    It should also be noted that the hydrogen sulfide inhalation 
exposure in the Fiedler et al. study ranged from 0.05 to 5.0 ppm. This 
is far below the lowest observed adverse effect levels (LOAELs) seen in 
the animal studies of neurotoxicity cited in EPA's notice of Intent to 
Lift the Stay and support materials. The Fiedler et al. study may 
indicate that hydrogen sulfide can cause adverse effects in humans at 
exposure levels (at least acute exposure levels) much lower than 
previously expected.
    6. New Hydrogen Sulfide Dosimetry Data. Commenters state that EPA 
has not considered new information on tissue dosimetry in determining 
the no observed adverse effect levels for chronic inhalation exposure 
to hydrogen sulfide. Commenters cited two studies that, in combination 
with the Fiedler et al. study, they contend demonstrate that the 
chronic human health effects are not likely at hydrogen sulfide 
concentrations of 5 ppm or below. Commenters cited the 2006 Schroeter 
et al. study (Ref. 7), in which the authors used computational fluid 
dynamics (CFD) modeling to quantitatively correlate hydrogen sulfide 
tissue dosimetry in rat and human nasal passages. Commenters state that 
assuming that equivalent hydrogen sulfide flux values will induce 
similar responses in the olfactory regions of rats and humans, the no 
observed adverse effect level-human equivalent concentration (NOAEL-
HEC) was estimated to be 5 ppm. Commenters also cited a 2010 Schroeter 
et al. study (Ref. 8) in which the authors investigated interhuman 
variability of hydrogen sulfide nasal dosimetry using anatomically 
accurate CFD models of the nasal passages of five adults and two 
children generated from magnetic resonance imaging (MRI) or computed 
tomography (CT) scan data. Commenters state that using allometrically 
equivalent breathing rates, the authors simulated steady-state 
inspiratory airflow and hydrogen sulfide uptake. Approximate locations 
of olfactory epithelium were mapped in each model to compare air : 
tissue flux in the olfactory region among individuals. The fraction of 
total airflow to the olfactory region ranged from 2 percent to 16 
percent. Despite this wide range in olfactory airflow, hydrogen sulfide

[[Page 64035]]

dosimetry in the olfactory region was predicted to be similar among 
individuals. Differences in the 99th percentile and average flux values 
were < 1.2-fold at inhaled concentrations of 1, 5, and 10 ppm. 
Commenters contend that these preliminary results suggest that 
differences in nasal anatomy and ventilation among adults and children 
do not have a significant effect on hydrogen sulfide dosimetry in the 
olfactory region.
    The Agency would like to thank the commenters for bringing 
additional primary research studies to our attention, enabling us to 
make decisions using all available resources. EPA agrees with the 
commenters in regard to consideration of the dosimetry information 
presented in both papers by Schroeter et al. This type of 
pharmacokinetic modeling and the results presented represent the 
current state-of-the-science for inhalation dosimetry and are being 
reviewed by EPA for its utility in addressing our current reference 
concentration (RfC) derivation methods (see http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=212131). However, it is important to note 
that the purpose of the papers by Schroeter et al. was to provide a 
model-based NOAEL-HEC (5 ppm), not an alternative final RfC which 
incorporates the application of uncertainty factors. Thus, the only 
part of the EPA's methods in deriving a value that is addressed is the 
calculation of an HEC extrapolated from animal data. No judgment is 
made by these authors that 5 ppm represents a replacement or 
alternative RfC or serves to replace or reduce the application of 
uncertainty factors. EPA's human health hazard assessment for hydrogen 
sulfide is based on the Agency's current IRIS toxicological profile 
(Ref. 3), and while this new dosimetry information and resulting NOAEL-
HEC might be considered in a revaluation of the current RfC, it does 
not impact EPA's assessment of the potential for hydrogen sulfide to 
cause chronic toxicity.
    The Agency does not concur with the commenter's conclusion that the 
Fiedler and Shroeter studies demonstrate that chronic human health 
effects are not likely at hydrogen sulfide concentrations of 5 ppm or 
below. As noted, the Fiedler study addresses solely acute exposures and 
is not relevant to chronic effects. Further, the Schroeter reports only 
provide data for use in calculating the NOEAL-HEC based on 
pharmacokinetic modeling. Therefore, the commenter's conclusions 
regarding chronic human health effects of hydrogen sulfide are not 
supported by the studies presented.
    7. No Need for TRI Reporting. Commenters contend that there is no 
need to include hydrogen sulfide on the Toxics Release Inventory. 
Commenters restated their claim that emissions of hydrogen sulfide 
reported under EPCRA section 313 cannot be reasonably anticipated to 
cause any of the chronic health effects covered by EPCRA section 
313(d)(2)(B). Commenters state that although accidental releases of 
hydrogen sulfide can result in serious adverse effects, such releases 
are subject to the emergency notification requirements of EPCRA section 
304 and by the Comprehensive Environmental Response, Compensation, and 
Liability Act (CERCLA) section 103. Commenters state that such 
accidental releases are expressly regulated pursuant to Clean Air Act 
(CAA) Section 112(r) and hydrogen sulfide is among the substances that 
were specifically identified for such regulation by Congress in Section 
112(r). Commenters also claim that since there is no evidence that 
suggests that routine releases of hydrogen sulfide pose any risk, 
nothing would be achieved by adding reporting requirements under EPCRA 
section 313. Commenters contend that since emissions of hydrogen 
sulfide that would typically be reported under EPCRA Section 313 are 
irrelevant to potential chronic health effects of the type addressed by 
EPCRA Section 313(d)(2)(B), and accidental releases of hydrogen sulfide 
that might be expected to present a potential hazard are well 
regulated, reporting under EPCRA Section 313 serves no purpose. 
Commenters claim that even if EPA has properly determined that hydrogen 
sulfide has ``moderately high to high chronic toxicity,'' EPA is not 
required to list hydrogen sulfide in these circumstances.
    Commenters state that in announcing its policy concerning use of 
exposure analyses in listing determinations under EPCRA Section 
313(d)(2), EPA stated:

    The statute is silent on the issue of exposure considerations 
for the section 313(d)(2)(B) and (C) criteria. The language of 
section 313 does not prohibit EPA from considering exposure factors 
when making a finding under either section 313(d)(2)(B) or section 
313(d)(2)(C) (59 FR 61441-61442).

    Commenters state that the reviewing court that reviewed this 
construction expressly affirmed this conclusion, stating that 
``chemicals of moderate or high toxicity are not necessarily added [to 
the list] because of it.'' Troy Corp. v. Browner, 120 F.3d at 287.
    Commenters claim that EPA has not cited any adverse consequence 
from the Administrative Stay of reporting requirements under EPCRA 
Section 313 that has been in place for over 15 years and that EPA 
should exercise its discretion to consider exposure factors in making a 
new listing determination for hydrogen sulfide and then rescind its 
prior listing determination.
    As EPA stated in response to the commenter's previous comments on 
the releases of hydrogen sulfide, EPA does not agree that the 
commenters have shown that releases of hydrogen sulfide will not cause 
the kinds of health and environmental effects that EPA cited as support 
for listing hydrogen sulfide. Most importantly, EPA is not required to 
show that the effects that hydrogen sulfide can cause are actually 
occurring in order to list it on EPCRA section 313. EPA notes that 
other commenters have provided comments alleging that they have 
experienced adverse health effects from hydrogen sulfide releases (see 
for example: EPA-HQ-TRI-2009-0844-0076, EPA-HQ-TRI-2009-0844-0081 in 
the docket for this action).
    Regarding the fact that accidental releases of hydrogen sulfide 
that may cause serious adverse health effects including death are 
covered by other statutes, this has no impact on the listing of a 
chemical under EPCRA section 313. Listing of a chemical under EPCRA 
section 313 is separate and apart from any other regulatory actions. 
EPCRA section 313 is focused on a community's right-to-know about 
releases of toxic chemicals, not emergency reporting requirements for 
industrial accidents.
    With regard to the commenter's statements that listing hydrogen 
sulfide on EPCRA section 313 serves no purpose, the Agency disagrees. 
As EPA has stated:

    It is important to understand that although an adverse effect is 
known or can be reasonably anticipated to be caused by a chemical on 
the section 313 list, a release of a chemical into a community does 
not necessarily mean that the effect will occur. Exposure and dose 
are also important factors in determining whether an adverse effect 
occurs and how serious the manifestation will be. The listing of a 
chemical on the section 313 list does not mean that a particular 
community will experience these adverse effects. Instead the purpose 
for listing a chemical is to ensure that the public gets information 
about releases of such chemicals. Thus, EPA believes that for 
chemicals that typically do not affect solely one or two species but 
rather affect changes across a whole ecosystem and for which there 
is well-documented evidence supporting the adverse effects, that 
their addition to the EPCRA section 313 list is warranted even 
though the severity of the adverse effects that they induce will be 
dependent upon site-specific characteristics. Once EPA makes release 
data available through TRI, the community may then make

[[Page 64036]]

its own determination on the importance of these releases (and their 
potential adverse effects). (59 FR 61433, 11/30/1994 (emphasis 
added)).

    Listing a chemical under EPCRA section 313 allows the public and 
governments to track and assess the impacts of chemical releases and 
make determinations as to whether or not a risk exists. Without release 
data, the public is limited in its ability to determine whether or not 
releases of a toxic chemical are impacting their health and/or 
environment. Even if releases are low and no adverse impacts are 
expected, that information is still of value to the public.
    The listing of hydrogen sulfide on EPCRA section 313 is consistent 
with EPA's stated policy on the use of exposure assessments, which does 
not include the use of exposure for chemicals such as hydrogen sulfide 
that have moderately high to high human toxicity and high ecotoxicity. 
The commenter suggests that EPA should exercise its discretion with 
regard to the consideration of exposure, citing Troy Corp v. Browner 
for the proposition that ``chemicals of moderate or high toxicity are 
not necessarily added [to the list] because of it.'' Placed in greater 
context, that quotation is as follows:

    The EPA's exposure policy merely informed the public that the 
agency would exercise its discretion by considering exposure only 
for low toxicity chemicals. The EPA did not thereby curtail this 
discretion; it did nothing more than clarify its own position. The 
policy does not impose rights or obligations or bind the agency to a 
particular result. Chemicals of low toxicity may be added despite 
the policy, just as chemicals of moderate or high toxicity are not 
necessarily added because of it. (Troy Corp. v. Browner, 120 F.3d at 
287).

    As the DC Circuit noted, EPA stated that it would exercise its 
discretion by considering exposure only for low toxicity chemicals. If 
EPA were to consider exposure for hydrogen sulfide it would be 
inconsistent with the Agency's stated policy on the use of exposure 
assessments in EPCRA section 313 listing decisions. While EPA does have 
discretion to deviate from its policy, the Agency does not believe that 
there is any reason to consider exposure in its listing decision for 
hydrogen sulfide and thus has no reason to deviate from its stated 
exposure policy.

B. Comments From the National Renderers Association

    The commenter stated that they do not support listing hydrogen 
sulfide emissions from rendering plants under EPCRA section 313 because 
of what they claim are extremely low levels of hydrogen sulfide 
potentially emitted from such facilities. The commenter stated that 
they agreed with EPA that, at certain concentration levels, exposure to 
hydrogen sulfide can cause significant adverse acute and chronic human 
health effects and adverse impacts to the environment. The commenters 
contend that these potentially harmful concentrations are well 
understood, published, and regulated under the Occupational Safety and 
Health Administration (OSHA) and the National Institute for 
Occupational Safety and Health (NIOSH) standards with which their 
facilities comply. The commenter stated that there are safe levels of 
hydrogen sulfide exposure and that the fence-line concentration of 
hydrogen sulfide at a typical rendering plant would be expected to be 
well below these safe levels. The commenter recommended that EPA take 
into account the ``concentration levels that are reasonably likely to 
exist beyond facility site boundaries as a result of continuous, or 
frequently recurring, releases,'' as required under EPCRA section 
313(d)(2)(A), and exempt the reporting of hydrogen sulfide as a by-
product of rendering operations.
    The commenter provided information on the natural sources of 
hydrogen sulfide and information that hydrogen sulfide degrades rapidly 
in the environment. The commenter stated that the typical rendering 
plant might emit roughly 400 pounds of hydrogen sulfide per year. The 
commenter stated that hydrogen sulfide can be found in very low 
concentrations throughout the rendering industry supply and processing 
chain as a by-product related to the recycling, collecting, handling 
and processing of animal byproduct and used cooking oil. The commenter 
claims that hydrogen sulfide releases in the rendering facility 
workplace environment tend to be fugitive in nature, inconsistent in 
concentration, and irregularly present. The commenter stated that the 
presence of hydrogen sulfide, if any, depends on the age of the raw 
materials, moisture content, temperature, state of anaerobic bacterial 
decay, and other factors. The commenter claimed that ``[h]ydrogen 
sulfide concentration emissions from a typical rendering plant likely 
result in air concentrations off-site that would be several orders of 
magnitude below concentrations that are potentially hazardous to human 
health and the environment.'' The commenter claims that as a result of 
these characteristics, the hydrogen sulfide that may be present in a 
rendering facility is not likely to reach site boundaries at any 
measurable or reliably quantifiable concentration. The commenters claim 
that through their years of studying potential hydrogen sulfide 
emissions in rendering operations, they know that it is difficult to 
quantify and report the low levels of emissions that may occur at their 
facilities. The commenter suggested that the addition of hydrogen 
sulfide to TRI listing must, at a minimum, allow for no TRI 
requirements for de minimums sources such as facilities in the 
rendering supply and processing chain.
    As EPA discussed in the Notice of Intent to Lift the Stay (75 FR 
8893, 8889, February 26, 2010), exposure consideration is not 
appropriate for chemicals that have moderately high to high chronic 
human health toxicity or high environmental toxicity. Hydrogen sulfide 
meets both of these criteria, therefore exposure (or the potential for 
exposure) is not a factor in the listing decision. Regarding EPCRA 
section 313(d)(2)(A), hydrogen sulfide is not listed under that 
criteria, but rather the criteria of EPCRA sections 313(d)(2)(B) and 
(C).
    It is well known that hydrogen sulfide is a byproduct of the 
rendering process (Ref. 9). EPA has published emission factors for at 
least one stage of the rendering process (Ref. 10). The commenter 
believes that reporting would be difficult for hydrogen sulfide, yet 
they provide an estimate of 400 pounds of releases per year, thus it 
appears that these facilities could make at least a reasonable estimate 
of releases as required under EPCRA section 313. EPA notes that 
rendering plants must already report their release of ammonia, another 
gas with variations in production and release. Regarding whether or not 
``emissions from a typical rendering plant likely result in air 
concentrations off-site that would be several orders of magnitude below 
concentrations that are potentially hazardous to human health and the 
environment,'' unless the release data is made available the local 
communities and governments will not be able to confirm this 
conclusion. EPCRA section 313 contains no provisions for de minimis 
sources other than the fact that facilities must exceed the reporting 
thresholds (25,000 pounds for manufacture and processing and 10,000 
pounds for otherwise use). It appears that rendering plants do not use 
hydrogen sulfide, thus they would have to manufacture or process 25,000 
pounds before they would have to file a report.

[[Page 64037]]

C. Comments From the American Meat Institute

    The commenters stated that they agree with the comments submitted 
by the National Renderers Association. The commenter stated that in 
their members' plants hydrogen sulfide is released primarily in 
rendering and waste treatment processes and that the releases are 
fugitive, can be widespread and are in concentrations that are 
irregular and inconsistent. The commenter stated that to comply with 
EPCRA Section 313, their members will have to estimate their releases 
to determine if the reporting thresholds are met. The commenter claimed 
that because of the ephemeral nature of the releases, standard field 
and even more sophisticated laboratory grade measurement devices are 
inadequate and unreliable. The commenter claimed that the releases 
disperse rapidly, resulting in concentrations below the measurement 
capability of some devices and, regardless of the measurement device, 
the measurements are not easily replicated. The commenter stated that 
meat packing and processing plants do not have a reliable method for 
determining compliance. The commenter stated that because of this they 
have significant concerns regarding how to implement EPCRA section 313 
with respect to hydrogen sulfide and contend EPA should consider such 
practical issues before lifting the stay.
    EPA notes that the ability of any one particular industry to be 
able to report releases is not a factor in determining whether a 
chemical meets the EPCRA section 313 listing criteria. It is well known 
that hydrogen sulfide is a byproduct of the rendering process (Ref. 9). 
EPA has published emission factors for at least one stage of the 
rendering process (Ref. 10). The commenter believes that reporting 
would be difficult for hydrogen sulfide, yet the National Renderers 
Association provided an estimate of 400 pounds of releases per year, 
thus it appears that these facilities could make at least a reasonable 
estimate of releases as required under EPCRA section 313. EPA notes 
that rendering plants as well as meat packing and processing plants 
must already report their release of ammonia, another gas that is also 
likely to have variations in production and release as it is also 
produced from the decay of organic matter. While EPA would like to 
collect the most accurate information possible, EPCRA section 313 only 
requires that facilities report a reasonable estimate of releases. EPA 
sees no reason why meat packing and processing plants should not be 
able to make at least reasonable estimates of the amounts of hydrogen 
sulfide manufactured and released.

VI. What are the references cited in this document?

    EPA has established an official public docket for this action under 
Docket ID No. EPA-HQ-TRI-2009-0844. The public docket includes 
information considered by EPA in developing this action, including the 
documents listed below, which are electronically or physically located 
in the docket. In addition, interested parties should consult documents 
that are referenced in the documents that EPA has placed in the docket, 
regardless of whether these referenced documents are electronically or 
physically located in the docket. For assistance in locating documents 
that are referenced in documents that EPA has placed in the docket, but 
that are not electronically or physically located in the docket, please 
consult the person listed in the above FOR FURTHER INFORMATION CONTACT 
section.

1. USEPA, OEI. Response to Comments Received on the February 26, 
2010, Federal Register Document (75 FR 8889): Hydrogen Sulfide; 
Community Right-to-Know Toxic Chemical Release Reporting; Intent to 
consider lifting the administrative stay; opportunity for public 
comment. U.S. Environmental Protection Agency, Office of 
Environmental Information, Office of Information Analysis and 
Access. July 21, 2011.
2. USEPA, Office of Water Regulations and Standards, Quality 
Criteria for Water, EPA 440/5-86-001 (May 1, 1986) (EPA Gold Book), 
page 268.
3. U.S. Environmental Protection Agency. ``Toxicological Review of 
Hydrogen sulfide, (CAS No. 7783-06-4), In Support of Summary 
Information on the Integrated Risk Information System.'' Washington, 
DC: Integrated Risk Information System. U.S. Environmental 
Protection Agency. June, 2003. http://www.epa.gov/ncea/iris/toxreviews/0061-tr.pdf. Integrated Risk Information Summary for 
Hydrogen Sulfide available at: http://www.epa.gov/ncea/iris/subst/0061.htm.
4. U.S. Environmental Protection Agency, Technical Review of 
Hydrogen Sulfide: Chemistry, Environmental Fate and Ecological 
Toxicity, CAS Registry Number 7783-06-4; Office of Environmental 
Information, Office of Information Access and Analysis, 
Environmental Analysis Division, Analytical Support Branch; June 22, 
2009.
5. Fiedler N., Kipen H., Ohman-Strickland P., Zhang J., Weisel C., 
Laumbach R., Kelly-McNeil K., Olejeme K., and Lioy P., ``Sensory and 
Cognitive Effects of Acute Exposure to Hydrogen Sulfide.'' Env. 
Health Persp. v. 116(1), (2008), pp. 78-85.
6. Skrajny, B., Hannah, R.S., Roth, S.H., ``Low concentrations of 
hydrogen sulphide alter monoamine levels in the developing rat 
central nervous system.'' Can. J. Physiol. Pharmacol. v. 70(11), 
(1992), pp. 1515-1518.
7. Schroeter J.D., Kimbell J.S., Andersen M.E., and Dorman D.C., 
``Use of a pharmacokinetic-driven computational fluid dynamics model 
to predict nasal extraction of hydrogen sulfide in rats and 
humans.'' Toxicol. Sci. v. 94(2), (2006), pp. 359-367.
8. Schroeter J.D., Garcia G.J. M., and Kimbell, J.S., ``A 
computational fluid dynamics approach to assess interhuman 
variability in hydrogen sulfide nasal dosimetry.'' Inhalation 
Toxicol. v. 22(4), (2010), pp. 277-286.
9. Emission Factor Documentation for AP-42 Section 9.5.3 Meat 
Rendering Plants Final Report. Prepared by Midwest Research 
Institute (MRI) for the Office of Air Quality Planning and Standards 
(OAQPS), U. S. Environmental Protection Agency (EPA), under EPA 
Contract No. 68-D2-0159. September 1995.
10. AP 42, Fifth Edition, January 1995. Compilation of Air Pollutant 
Emission Factors, Volume I: Stationary Point and Area Sources. 
Chapter 9: Food and Agricultural Industries section 9.5.3 Meat 
Rendering Plants. Office of Air Quality Planning and Standards 
(OAQPS), Office of Air and Radiation, U.S. Environmental Protection 
Agency (EPA).

List of Subjects in 40 CFR Part 372

    Environmental protection, Community right-to-know, Reporting and 
recordkeeping requirements, and Toxic chemicals.

    Dated: September 8, 2011.
Lisa P. Jackson,
Administrator.

    Therefore, 40 CFR part 372 is amended as follows:

PART 372--[AMENDED]

0
1. The authority citation for part 372 continues to read as follows:

    Authority:  42 U.S.C. 11023 and 11048.

Sec.  372.65  [Amended]

0
2. Section 372.65 is amended by lifting the stay on hydrogen sulfide 
and methyl mercaptan entries and all related dates under paragraph (a) 
and under paragraph (b), lifting the stay on the entries for CAS Nos. 
74-93-1 and 7783-06-04 and all related dates.

[FR Doc. 2011-23534 Filed 10-14-11; 8:45 am]
BILLING CODE 6560-50-P