64022 Federal Register / Vol. 76, No. 200 / Monday, October 17, 2011 / Rules and Regulations 

• Is not subject to requirements of 

Section 12(d) of the National 

Technology Transfer and Advancement 

Act of 1995 (15 U.S.C. 272 note) because 

application of those requirements would 

be inconsistent with the CAA; and 

• Does not provide EPA with the 

discretionary authority to address, as 

appropriate, disproportionate human 

health or environmental effects, using 

practicable and legally permissible 

methods, under Executive Order 12898 

(59 FR 7629, February 16, 1994). 

In addition, this rule does not have 

Tribal implications as specified by 

Executive Order 13175 (65 FR 67249, 

November 9, 2000), because the SIP is 

not approved to apply in Indian country 

located in the state, and EPA notes that 

it will not impose substantial direct 

costs on Tribal governments or preempt 

Tribal law. 

B. Submission to Congress and the 

Comptroller General 

The Congressional Review Act, 5 

U.S.C. 801 et seq., as added by the Small 

Business Regulatory Enforcement 

Fairness Act of 1996, generally provides 

that before a rule may take effect, the 

agency promulgating the rule must 

submit a rule report, which includes a 

copy of the rule, to each House of the 

Congress and to the Comptroller General 

of the United States. EPA will submit a 

report containing this action and other 

required information to the U.S. Senate, 

the U.S. House of Representatives, and 

the Comptroller General of the United 

States prior to publication of the rule in 

the Federal Register. A major rule 

cannot take effect until 60 days after it 

is published in the Federal Register. 

This action is not a ‘‘major rule’’ as 

defined by 5 U.S.C. 804(2). 

C. Petitions for Judicial Review 

Under section 307(b)(1) of the CAA, 

petitions for judicial review of this 

action must be filed in the United States 

Court of Appeals for the appropriate 

circuit by December 16, 2011. Filing a 

petition for reconsideration by the 

Administrator of this final rule does not 

affect the finality of this action for the 

purposes of judicial review nor does it 

extend the time within which a petition 

for judicial review may be filed, and 

shall not postpone the effectiveness of 

such rule or action. 

This action concerning Maryland’s 

adoption of CTG standards for plastic 

parts and business machines coatings 

may not be challenged later in 

proceedings to enforce its requirements. 

(See section 307(b)(2).) 

List of Subjects in 40 CFR Part 52 

Environmental protection, Air 

pollution control, Incorporation by 

reference, Ozone, Reporting and 

recordkeeping requirements, Volatile 

organic compounds. 

Dated: October 03, 2011. 

W.C. Early, 

Acting, Regional Administrator, Region III. 

40 CFR part 52 is amended as follows: 

PART 52—[AMENDED] 

■ 1. The authority citation for part 52 

continues to read as follows: 

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

Subpart V—Maryland 

■ 2. In § 52.1070, the table in paragraph 

(c) is amended by revising the entry for 

COMAR 26.11.19.07 and adding an 

entry for COMAR 26.11.19.07–2 to read 

as follows: 

§ 52.1070 Identification of plan. 

* * * * * 

(c) * * * 

EPA-APPROVED REGULATIONS IN THE MARYLAND SIP 

Code of Maryland 

administrative 

regulations (COMAR) 

citation 

Title/subject State effective 

date EPA approval date 

Additional explanation/ 

citation at 40 CFR 

52.1100 

*******

26.11.19 Volatile Organic Compounds from Specific Processes 

*******

26.11.19.07 ............... Paper, Fabric, Film, and Foil Coating ................... 5/16/11 10/17/11 [Insert page 

number where the 

document begins].

Revisions to Section title 

and Sections .07A 

and .07C(3). 

* * * * * * * 

26.11.19.07–2 ........... Plastic Parts and Business Machines Coating ..... 5/16/11 10/17/11 [Insert page 

number where the 

document begins].

New Regulation. 

* * * * * * * 

* * * * * 

[FR Doc. 2011–26638 Filed 10–14–11; 8:45 am] 

BILLING CODE 6560–50–P 

ENVIRONMENTAL PROTECTION 

AGENCY 

40 CFR Part 372 

[EPA–HQ–TRI–2009–0844; FRL–9463–5] 

RIN 2025–AA27 

Hydrogen Sulfide; Community Rightto-Know Toxic Chemical Release 

Reporting 

AGENCY: Environmental Protection 

Agency (EPA). 

ACTION: Lifting of Administrative Stay 

for Hydrogen Sulfide. 

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 


rmajette on DSK29S0YB1PROD with RULES
Federal Register / Vol. 76, No. 200 / Monday, October 17, 2011 / Rules and Regulations 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; email: bushman.daniel@epa.gov, for 

specific information on this document. 

For general information on EPCRA 

section 313, contact the Emergency 

Planning and Community Right-toKnow 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 


rmajette on DSK29S0YB1PROD with RULES
64024 Federal Register / Vol. 76, No. 200 / Monday, October 17, 2011 / Rules and Regulations 

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/m3) (20 parts per 

million (ppm)) for neurotoxicity and 

41.7 mg/m3 (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 


rmajette on DSK29S0YB1PROD with RULES
Federal Register / Vol. 76, No. 200 / Monday, October 17, 2011 / Rules and Regulations 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 


rmajette on DSK29S0YB1PROD with RULES
64026 Federal Register / Vol. 76, No. 200 / Monday, October 17, 2011 / Rules and Regulations 

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. 


rmajette on DSK29S0YB1PROD with RULES
Federal Register / Vol. 76, No. 200 / Monday, October 17, 2011 / Rules and Regulations 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 


rmajette on DSK29S0YB1PROD with RULES
64028 Federal Register / Vol. 76, No. 200 / Monday, October 17, 2011 / Rules and Regulations 

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 


rmajette on DSK29S0YB1PROD with RULES
Federal Register / Vol. 76, No. 200 / Monday, October 17, 2011 / Rules and Regulations 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/m3 (20 ppm) 

and 41.7 mg/m3 (30 ppm). In addition, EPA’s 

technical evaluation of hydrogen sulfide also 

shows that it can reasonably be anticipated 


rmajette on DSK29S0YB1PROD with RULES
64030 Federal Register / Vol. 76, No. 200 / Monday, October 17, 2011 / Rules and Regulations 

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 wellaerated 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/m3 (20 ppm) 

and 41.7 mg/m3 (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 


rmajette on DSK29S0YB1PROD with RULES
Federal Register / Vol. 76, No. 200 / Monday, October 17, 2011 / Rules and Regulations 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/m3) 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 wellaerated 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 

(mg/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 mg/L 

undissociated H2S would not be hazardous to 

most fish and other aquatic wildlife, but 

concentrations in excess of 2.0 mg/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 

mg/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 


rmajette on DSK29S0YB1PROD with RULES
64032 Federal Register / Vol. 76, No. 200 / Monday, October 17, 2011 / Rules and Regulations 

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- theevidence 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). 


rmajette on DSK29S0YB1PROD with RULES
Federal Register / Vol. 76, No. 200 / Monday, October 17, 2011 / Rules and Regulations 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: 


rmajette on DSK29S0YB1PROD with RULES
64034 Federal Register / Vol. 76, No. 200 / Monday, October 17, 2011 / Rules and Regulations 

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 postexposure 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 


rmajette on DSK29S0YB1PROD with RULES
Federal Register / Vol. 76, No. 200 / Monday, October 17, 2011 / Rules and Regulations 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 


rmajette on DSK29S0YB1PROD with RULES
64036 Federal Register / Vol. 76, No. 200 / Monday, October 17, 2011 / Rules and Regulations 

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 byproduct 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. 


rmajette on DSK29S0YB1PROD with RULES
Federal Register / Vol. 76, No. 200 / Monday, October 17, 2011 / Rules and Regulations 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-toKnow 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., KellyMcNeil 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] 

■ 1. The authority citation for part 372 

continues to read as follows: 

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

§ 372.65 [Amended] 

■ 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 


rmajette on DSK29S0YB1PROD with RULES