### U.S. Environmental Protection Age ncy Documentation of OMB Review Under Executive Order 12866 Title of Action: !"#$%&'()*+,-.#'/)0%11+(.2")3.&42

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5 @@FL Although this action does not constitute a “rule,” “regulation,” or “regulatory action” within the meaning of Executive Order (E.O.) 12866 , t his action was submitted to the Office of Management and Budget (OMB) for review under E.O. 12866 , titled Regulatory Plannin g and Review (58 FR 51735, October 4, 1993). Whenever EPA makes publicly available a n action that was reviewed under E.O. 12866, section 6(a)(3)(E) of the E.O. directs the Agency to also: (1) Make available to the public a copy of the information that was pro vided to OMB’s Office of Information and Regulatory Affairs (OIRA) for review under the E.O., i.e., the text of the draft action and, if applicable, an assessment of the potenti al costs and benefits, as well as additional information for those actions that are determined to be economically significant under the E.O. (Information requirements are described in sections 6(a)(3)(B) and (C)). (2) Identify for the public any substantive changes between the draft submitted to OIRA and the action that was subsequently issued, using a method that is complete, clear, and simple. (3) Identify for the public those substantive changes made at the suggestion or recommendation of OIRA. For this action, were substantive changes made to information reviewed under E.O. 12866? [Please check the appropriate answer.] ! No. [In the docket, include the information identified in item (1) below.] 

## ! Yes. [In the docket, include the information identified in items (1)

– (3) below.] Accordingly, the Agency has included this form and the following information in the public docket for this action: [Please check the appropriate information.] ! (1) A copy of the information that was provided to OIRA for review under the E.O. 

## ! (2) Documentation of any substantive changes made to the draft text that was submitted to OIRA when compared with what was subsequently made publicly available. The documentation is provided on the pages following this form. Changes made at the suggestion or recommendation of OIRA, if any, are clearly identified through attribution to OIRA. EPA has used one or more of the following methods to note changes: [Select the appropriate option(s).] 

## ! (a) Redline
- Strikeout

– A copy of the draft action submitted, using redline

- strikeout to show the substantive changes that were made. 

## ! (b) Hand Markup

– A copy of the draft action submitted, using handwritten notes to show the substantive changes that were made. 

## ! (c) Note to the file

- A document that identifies the substantive changes that were made, with page and paragraph references to the draft action that was submitted. If you have any questions about this action or this documentation, please call the contact:
Name: Daniel Bushman Email: bushman.daniel@epa.gov Phone: 202

- 566

- 0743 Revised 06/17 /2011Internal Draft Document Only; Do Not Cite, Quote or Release.

Page 1 of 56 ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 372 [EPA
- HQ
- TRI
- 2009
- 0844; FRL

– XXXX
- X]
RIN 2025
- AA27 Hydrogen Sulfide; Community Right
- to
- Know Toxic Chemical Release Reporting
AGENCY: Environmental Protection Agency (EPA).
ACTION: Lifting of Administrative Stay for Hydrogen Sulfide
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 Abst racts 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 December 1, 1993. However, on August 22, 1994, EPA issued an Administrative Stay o f 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 it s 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 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 commentsInternal Draft Document Only; Do Not Cite, Quote or Release.

Page 2 of 56 received on the notice of intent, EPA continu es 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 repo rting requirements for hydrogen sulfide.
DATES: This action is effective on November 30, 2010.
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 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
mater ial, will be publicly available only in hard copy. Publicly available docket materials are available either electronically in www.regulations.gov or in hard copy at the OEI Docket, EPA/DC, EPA West, Room 3334, 1 301 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; telephon e number: 202

- 566

- 0743; fax number: 202

- 566

- 0677; e

- mail: bushman.daniel@epa.gov , for specific information on this document. For general information on EPCRA section 313, contact the Emergency Plannin g and Community Right

- to

- Know Hotline , toll free at (800) 424

- 9346 or (703) 412

- 9810 in Virginia and Alaska or toll free, TDD (800) 553

- 7672, http://www.epa.gov/epaoswer/hotline/.
SUPPLEMENTARY INFORMATION:Internal Draft Document Only; Do Not Cite, Quote or Release.

Page 3 of 56 I. General Information A. Does this Action App ly 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*, 212 324*, 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 (corresp onding 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, 2211 12, 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 (Limite d 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 se rvices 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 se q.) (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 lis ted in the table haveInternal Draft Document Only; Do Not Cite, Quote or Release.

Page 4 of 56 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 appli cability 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" s ection.
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 w aste 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 establ ished 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 the Section 313(d)(2) criteria. Therefore, to remove a chemica l, EPA must demonstrate that none of the criteria are met. The EPCRA section 313(d)(2) criteria

are:Internal Draft Document Only; Do Not Cite, Quote or Release.

Page 5 of 56 (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) i ts 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 w arrant 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) crit erion 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 theInternal Draft Document Only; Do Not Cite, Quote or Release.

Page 6 of 56 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 p etitions 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) criteri a 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

o f 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 criteri a 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 issue d 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 revie w of the currently available data on the human health and environmental effects of hydrogen sulfide

– specifically, chronic respiratory effects, chronicInternal Draft Document Only; Do Not Cite, Quote or Release.

Page 7 of 56 neurotoxic effects, and acute, chronic and early

- life stage aquatic toxicity

– and EPA’s belief that th e 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 und er 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 “chro nic 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 li st 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 w as dictated by 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 ?Internal Draft Document Only; Do Not Cite, Quote or Release.

Page 8 of 56 EPA’s technical evaluation of hydrogen sulfide , as discussed in detail in the February 26,
2010 Federal Register document (75 FR 8889), shows that it can reasonably be anticipated to

cause chronic health effects in humans . The chronic health effects have been observed in laboratory animals at concentrations as low as 28 milligrams per cubic meter (mg/m 3 ) (20 parts per million (ppm ) ) and 41.7 mg/m 3 (30 ppm). In addition, EPA’s technical evaluation of hydrogen sulfide also shows that it can reasonably be anticipated to cause , because of its toxicity, significant adverse effects in aquatic organisms . Examples of hydrogen sulfide’s e cological toxicity include acute toxicity (96

- hour LC 50 (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 4 30

- 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 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, i n accordance with EPA’s stated policy on the use of exposure assessments (59 FR 61432), EPA does not believe that an exposure assessment is appropri ate for determiningInternal Draft Document Only; Do Not Cite, Quote or Release.

Page 9 of 56 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

. 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 Admin istrative 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.
IV. What Comments Did EPA Receive o n the Intent to Consider Lifting t he 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 individ uals, 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 an d 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 informati on 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 H ydrogenInternal Draft Document Only; Do Not Cite, Quote or Release.

Page 10 of 56 S ulfide C onsortium , whose members are: America n 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

. T he 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 acco mplished 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 pr o posed 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 l ifting the administrative stay of the EPCRA reporting requirements for hydrogen sulfide. Before addressing each of these 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 theInternal Draft Document Only; Do Not Cite, Quote or Release.

Page 11 of 56 listing criteria specified in section 313(d)(2). Therefore, to add a chemical, EPA must demonstrate that at least one crite rion 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

es tablishing 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 environmen tal 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 fin ding 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 that the Agency cited the same acute aquatic toxicity as an
“env i ronmental 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 res piratory effects as a “chronic human health effects” basis under EPCRA section 313(d)(2)(B) in the pr o posed rule, but chronic neurotoxic effects as a “chronic human health effects” basis under that same provision in the final rule. In addition, after issu ance of the final rule, some members of the regulated community expressed concern thatInternal Draft Document Only; Do Not Cite, Quote or Release.

Page 12 of 56 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 pr actice. Notably, however, the final rule adding hydrogen sulfide to the EPCRA section 313 list was never administratively or judicially challenged. 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 dictated by 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 2 2, 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 infor mation 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. On February 26, 2010, EPA issued a notice announcing its “Intent to consider lifting [the hydrogen sulfide] administrative stay; opportunity for public co mment.” 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 LiftInternal Draft Document Only; Do Not Cite, Quote or Release.

Page 13 of 56 the Stay notic e 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 r equirements for hydrogen sulfide should be lifted

. ” Id . at 8889 (emphasis added). Again, the final rule of December 1, 1993 adding hydrogen sulfide to the EPCRA section 313 list of toxic chemicals was never administratively or judicially challenged.

a
. E PA 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 de termination 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 di ssolve today’s Administrative Stay. ( 59 FR at 43049). Commenters have pointed to no authority which requires the Agency to revisit a final EPCRA section 313 listing determination in order to lift a subsequently issued stay of the reporting requirements th at flow from that listing determination, regardless of the potential issues that the Agency may have anticipated as requiring future consideration when it issued the stay. The Notice announcing the stay was not a proposed or final rule or a regulation for mulated through notice and comment rulemaking, and it changed no regulatory text. See, e.g., 59 FR atInternal Draft Document Only; Do Not Cite, Quote or Release.

Page 14 of 56 43050 (“. . . the Agency does not regard today’s action as a rule. . . .”). Furthermore, even if the stay were a proposed or final rule, which it is not , the statement s at issue would constitute nothing more than preamble statement s and, “[w]hile preamble statements may in some unique cases constitute bin d ing, final agency action susceptible to judicial review, this is not the norm. Agency statements ‘ha ving general applicability and legal effect’ are to be published in the Code of Federal Regulations. ” Natural Resources Defence Council v. EPA , 559 F.3d 561, 564

– 65 (D.C. Cir. 2009) (citations omitted). As such, the statement s on which the commenters are focused simply are not binding on the Agency or outside parties. 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 listi ng determination, which was never administratively or judicially challenged. The 1993 listing decision was dictated by the acute aquatic toxicity finding alone under EPCRA section 313(d)(2)(C), which was included in both the proposed and final rules and n ever challenged. 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 invited comment on the data underlying its consideration of the matter. As descri bed in the Intent to Lift the Stay notice, that intent is 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 ef

fects in aquatic organisms (acute, chronic, and early life stage). Based on these findings, EPA believes that there is no basis for continuing the administrative stay of the reporting requirementsInternal Draft Document Only; Do Not Cite, Quote or Release.

Page 15 of 56 for hydrogen sulfide, and that the administrative stay sho uld therefore be lifted. Moreover, these findings also demonstrate that there is no basis to even 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 sufficien t 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 o f lifting the administrative stay demonstrate, EPA cannot show that none of the criteria are met. b

. Proposed and Final Chronic Human Health Effects

. Second, c ommenters argue that EPA cannot now limit comment to whether or not to lift the stay because EP A 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) cr i teria are: (A) The chemical is known to cause or can reasonably be anticipated to cause significant adverse acute human health effects at concentrat ion levels that are reasonably likely to exist beyond facility site boundaries as a result of continuous, or fr e quently recurring, releases. (B) The chemical is known to cause or can reasonably be anticipated to cause in humans

- (i) Cancer or teratogeni c effects, or (ii) Serious or irreversible

- (I) Reproductive dysfunctions,Internal Draft Document Only; Do Not Cite, Quote or Release.

Page 16 of 56 (II) Neurological disorders, (III) Heritable genetic mutations, or (IV) Other chronic health effects. (C) The chemical is known to cause or can be reasonably anticipa ted 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 suff i cient 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 criterio n;” 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 pr o posed rule, but ch ronic 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 “env i ronmental effects” basis for th e 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 ” o f the listing criteria (emphasis added), the 1993 listing decision was dictated by the acute aquatic toxicity finding alone under EPCRA section 313(d)(2)(C). That basis for the listing was never challenged and was and continues to beInternal Draft Document Only; Do Not Cite, Quote or Release.

Page 17 of 56 supported by the data . 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. 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 dat a, 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 Policy. Third, c ommenters argue that EPA cannot now limit comment to whether or not to lift the stay because EPA adopted its current poli cy 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. Inste ad, t he Agency’s then

- existing position on the use of exposure analyses in listing decisions under EPCRA section 313 was presented in a pr o posed rule in the Federal Register of January 12, 1994 ( 59 FR 1788 ). That proposed rule provided the public with the oppo r tunity to comment on the Agency’s then

- existing interpretation of the statutory listing criteria as it relates to the use of exposure consider a tions. 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 howInternal Draft Document Only; Do Not Cite, Quote or Release.

Page 18 of 56 exposure is considered in listing decisions. Subsequent to that final rule, EPA’s interpretation of the statu tory 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 s tated 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 determination s 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 cons istent 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 D.C. Circuit agreed with EPA, finding: Were the EPA to abandon a long

- held exposure po l icy and take a new direction we would, as urged, r e quire 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 whenInternal Draft Document Only; Do Not Cite, Quote or Release.

Page 19 of 56 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

w hich the agency articulated a policy contrary to the one expl i cated 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. Bro wner , 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 b y 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 sug gest, 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 ant icipated 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 chronicInternal Draft Document Only; Do Not Cite, Quote or Release.

Page 20 of 56 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 ecotoxicit y) 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 signif i cant 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, 614 40

- 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 th e 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 itsInternal Draft Document Only; Do Not Cite, Quote or Release.

Page 21 of 56 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 determination 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 moderat ely 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 ha s “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 interpreta tion 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 wi ll 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 equitab le 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.
E PA 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 analysi s in EPCRA sectionInternal Draft Document Only; Do Not Cite, Quote or Release.

Page 22 of 56 313 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 moderat e 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 provide d 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 con sidered 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, was explained in detail in the 1994 chemical expansion rule:
3. Ha zard 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 environmentalInternal Draft Document Only; Do Not Cite, Quote or Release.

Page 23 of 56 effects. In addition, EPA reviewed, where appropriate, information on the environmental fate of the chemical. The hazard assessment was conducted in accordance with rel evant 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 Asse ssment 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 nat ure 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 lev el 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 tha t 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 a bove 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 hea lth effects), and, where appropriate, under section 313(d)(2)(C) (i.e., based on adverse ecological effects). For chemicals listed under EPCRA sectionInternal Draft Document Only; Do Not Cite, Quote or Release.

Page 24 of 56 313(d)(2)(A), this analysis included estimated concentrations of the chemical at or beyond the facility s ite boundary through the use of estimated releases and modelling 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 base d 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 bei ng 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 eff ects 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 impairi ng 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 advers e effectInternal Draft Document Only; Do Not Cite, Quote or Release.

Page 25 of 56 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 suppo rting 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 rulemak ing, 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 consi dered 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 listi ng/delisting determinations previous to this action, including a number of deletions of low toxicity chemicals that Congress placed on the initial EPCRA sectionInternal Draft Document Only; Do Not Cite, Quote or Release.

Page 26 of 56 313 list. EPA is currently reviewing the one exception, inorganic fluorides, to determine if a dditional 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).
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), the court held: The Agency ... adequately explained and doc u mented its decision making process in the administr a tive record. EPA made a fi nding that all of the chemicals that were being listed under Section 313(d)(2)(B) in this rulemaking were of high

or mo d erately high toxicity, and that consideration of exposure was therefore not appropriate for these chemicals. See 59 Fed.Reg. 61,442... . W hat 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. Plaintiffs here have failed to show that EPA was u n reasonable or arbitrary
in exercising its discretion. Because EPA’s decision to not consider exposure in this rulemaking was consistent with its policy of u s ing exposure data only in particular circumstances, i.e., where chemicals are of low toxicity, the Court concludes that the A gency was not arbitrary and c a pricious. ( National Oilseed Processors, 924 F. Supp. at 1203

- 1204 (footnote omitted)). As with the chemicals in the 1994 chemical expansion rule and all other EPA listing actions, EPA conducted a hazard assessment of the hum an health and ecological effects of hydrogen sulfide. Based on the data from the hazard assessment, as presented in the FederalInternal Draft Document Only; Do Not Cite, Quote or Release.

Page 27 of 56 Register notice and supporting documents, EPA determined that hydrogen sulfide is moderately high to highly toxic to humans and 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 referenc es, and ecological effects were discussed in detail beginning on page 8893, with references. The determinations that hydrogen sulfide has moderately high to high human toxicity and high ecotoxicity were based on these hazard assessments, just as EPA did i n the 1994 chemical expansion rule and other previous listing decisions. 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 o f hydrogen sulfide shows that it can reasonably be anticipated to cause chronic health effects in humans. The chronic health effects have been observed in laboratory animals at concentrations as low as 28 mg/m 3 (20 ppm) and 41.7 mg/m 3 (30 ppm). In addition , EPA’s technical evaluation of hydrogen sulfide also shows that it can reasonably be anticipated to cause, because of its toxicity, significant adverse effects in aquatic organisms. Examples of hydrogen sulfide’s ecological toxicity include acute toxicity (96

- hour LC 50 ) 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 iden tify the information and the rationaleInternal Draft Document Only; Do Not Cite, Quote or Release.

Page 28 of 56 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 rati onale 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 concernin g 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 rela tion between the hazard assessments prepared by EPA scientist s 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 tha t 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 (p pb)) 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 ci te d 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. CommentersInternal Draft Document Only; Do Not Cite, Quote or Release.

Page 29 of 56 also cited established state ai r 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 H 2 S is oxidized in well

- aerated water by natural biological systems to sul fates or is biologically oxidized to elemental sulfur has caused investigators to minimize the toxic effects of H 2 S 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 g uidance 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 effect s 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 conta ined 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 Tec hnical Review of Hydrogen Sulfide?”), including references, can be found ( and need not be reiterated here ) . EPA then concluded, based on the hazard assessment:Internal Draft Document Only; Do Not Cite, Quote or Release.

Page 30 of 56 EPA has determined that hydrogen sulfide can reasonably be anticipated to cause serious or irre versible 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 docu ment that discussed the rationale for lifting the stay, EPA provided the following summary of the hazard data: EPA’s technical evaluation of hydrogen sulfide shows that it can reasonably be anticipated to cause chronic health effects in humans. The chronic health effects have been observed in laboratory animals at concentrations as low as 28 mg/m 3 (20 ppm) and 41.7 mg/m 3 (30 ppm). In addition, EPA’s technical evaluation of hydrogen sulfide also shows that it can reasonably be anticipated to cause, because o f its toxicity, significant adverse effects in aquatic organisms. Examples of hydrogen sulfide’s ecological toxicity include acute toxicity (96

- hour LC 50 ) values for freshwater fish that ranged from 0.0149 mg/L (fathead minnow) to 0.0448 mg/L (bluegill), i ndicating 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 indicatingInternal Draft Document Only; Do Not Cite, Quote or Release.

Page 31 of 56 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 effect s. 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 moder ately high to high human toxicity or high ecological toxicity. The toxicity of a chemical is separate from whether exposures to that chemical occur or not. In addition, the information provided by the commenter does not demonstrate that releases of hydro gen 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 t hat 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 sulfide of 10 ppb is not a basis for discounting the toxic ef fects of hydrogen sulfide. As EPA has stated: “Recent reviews of the health hazards associated with H 2 S exposure and subsequent treatment include Milby and Baselt (1999a) and Guidotti (1996). Earlier reviews of the health effects were provided by Glass (1 990), Reiffenstein et al. (1992), and Mehlman (1994). Exposure to H 2 S has been reported to be an important cause of morbidity andInternal Draft Document Only; Do Not Cite, Quote or Release.

Page 32 of 56 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 H 2 S is an inadequate warning indicator of exposure since levels in the range of 100

- 200 ppm (140

- 280 mg/m 3 ) can lead to loss of smell followed by olfactory paralysis (Reiffenstein et al., 1992).” (IRIS, 2003, page 10 (Ref. 3) ). In addition, simply because someone can smell hydrogen sulfide does not mean they will automatically remove themselves from that exposure. Individuals that are frequently exposed to hydrogen sulfide may become less sensitive to the smell and , as indicated in the IRIS assessment, it is possible to have loss of smell from hydrogen sulfide exposure. Commenters further state that: EPA bases its evaluation that H 2 S 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 H 2 S 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 H 2 S 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 H 2 S on fish and other aquatic life. (Footnotes omitted) The quote from the water quality criteria document that “[t]he fact that H 2 S is oxidized inInternal Draft Document Only; Do Not Cite, Quote or Release.

Page 33 of 56 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 H 2 S 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 do cument 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 o f just 2 micrograms per liter ( ! g/L) undissociated hydrogen sulfide for fish and other aquatic life in both fresh and marine water. Concerning oxidation, the EPA Gold Book states: The degree of hazard exhibited by sulfide to aquatic animal life is depende nt on the temperature, pH, and dissolved oxygen. At lower pH values a greater proportion is in the form of the toxic undissociated H 2 S. In winter when the pH is neutral or below or when dissolved oxygen levels are low but not lethal to fish, the hazard f rom 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. C onsequently, 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 co nditions, demonstrate hydrogen sulfide toxicity at lower concentrations. ( EPA Gold Book, May 1, 1986, page 268, (Ref. 2)). and concludes that:Internal Draft Document Only; Do Not Cite, Quote or Release.

Page 34 of 56 “Available data indicate that water containing concentrations of 2.0 ! g/L undissociated
H 2 S would not be hazardo us to most fish and other aquatic wildlife, but concentrations in excess of 2.0 ! g/L would constitute a long

- term hazard .” ( EPA Gold Book, May 1, 1986, page 270 (emphasis added) (Ref. 2) ). The conclusion that a concentration of hydrogen sulfide in excess o f just 2.0 ! g/L would constitute a long

- term hazard to aquatic life supports a determination that hydrogen sulfide is clearly highly toxic and a potential hazard to aquatic life despite its fate under certain environmental conditions. If hydrogen sulfide were not highly toxic to fish and other aquatic life, then there would be no need for such a very low water quality criteria value. Regarding the two references cited by the commenters concerning oxidation of hydrogen sulfide in seawater and aqueous solut ions (i.e., Millero, F.J., Hubinger, Fernandez and Garnett (1987). Oxidation of H 2 S 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 Sulf ur 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 (see 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, 200 9, in the docket). 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. However, the fact that hydrogen sulfide can be oxidized under certain environmental c onditions does not mean that it is not highly toxic. As was cited above, the EPA Gold Book stated:Internal Draft Document Only; Do Not Cite, Quote or Release.

Page 35 of 56 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 pr oportion is in the form of the toxic undissociated H 2 S. 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 c an 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 signi ficant 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 th e 48 and 96 hour LC 50 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 not es that, other than the single quote from the water quality criteria document andInternal Draft Document Only; Do Not Cite, Quote or Release.

Page 36 of 56 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 i n EPA’s hazard assessment. The summary table of the aquatic toxicity values presented in the hazard assessment provided over 90 toxicity values from more than a dozen sources. If the commenters did not believe that all this information supports a finding that hydrogen sulfide is highly toxic to aquatic organisms, then it would have been helpful if they could have provided specific comments on why those data should not be considered sufficient to support EPA’s conclusions. With regard to the commenters’ s tatements concerning criteria or guidance for determining whether a chemical has moderately high to high human toxicity or high ecological toxicity, the commenters appear to have been looking for some type of bright

- line numerical criteria. The comments r egarding 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 criteria, EPA would not agree that bright

- line numerical criteria 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 subst antiate 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 qualit y and quantity of the available data, including the nature of the data (e.g., humanInternal Draft Document Only; Do Not Cite, Quote or Release.

Page 37 of 56 epidemiological, laboratory animal, field or workplace studies) and confidence level in the existing data base, were all considered. Where a careful review of the scienti fic 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 tha t 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 th e 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 hydr ogen sulfide. Establishing a bright

- line numerical criteria 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 mill igrams per kilogram per day (mg/kg/day) and another chemical causes multiple serious effects acrossInternal Draft Document Only; Do Not Cite, Quote or Release.

Page 38 of 56 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 bright

- line numerical criteria, a quick review of the chemicals included in the 1 994 chemical expansion rule (59 FR 61432, 11/30/1994), the Persistent, Bioaccumulative, and Toxic (PBT) 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 th ose 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 ev aluated. Even if EPA were to establish a bright

- line numerical criteria, based on EPA’s previous listing determinations the levels at which hydrogen sulfide causes toxicity would be well below any such numerical criteria. EPA notes that other programs wi thin the Agency that have numerical criteria for aquatic organisms have set numerical criteria that are consistent with the kind of toxicity concentrations that EPA has identified has being highly toxic in EPCRA section 313 evaluations. For example, the O ffice of Pesticide Programs cites the following: Aquatic Organisms: Acute Concentration (ppm) Toxicity Category <0.1 very highly toxic 0.1

– 1 highly toxic >1

– 10 moderately toxic >10

– 100 slightly toxicInternal Draft Document Only; Do Not Cite, Quote or Release.

Page 39 of 56 >100 practically nontoxic (http://www.epa. gov/oppefed1/ecorisk_ders/toera_analysis_eco.htm#Ecotox). Under the above numerical criteria, 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 Ju dgment 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 magni tude 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 e ffects 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 tha t 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 hig h 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 possibil ity is that EPA scientists have simply made a qualitative judgmentInternal Draft Document Only; Do Not Cite, Quote or Release.

Page 4 0 of 56 concerning the plausibility that H 2 S 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 expo sure 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 tox icity 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 an d is highly toxic to aquatic organisms. The toxicity of a chemical is an intrinsic property of the chemical; it is not based on exposure levels. Unlike the intrinsic toxicity of a chemical, exposure levels can change depending on many factors such as rel ease quantities, type of release, changes in weather patters, 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

sec tion 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 chemical s 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 theInternal Draft Document Only; Do Not Cite, Quote or Release.

Page 41 of 56 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). The U.S. Court of Appeals for the District of Columbia Circuit, in upholding EPA’s interpretation of EPCRA section 313 listing decisions as it relates to the use of exposure provided a very go od example of the difference between the toxicity of a chemical and exposure to that chemical: 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’ t he 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 r eptile 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 o f 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 snake in a glass cage provides a perfect illustration of the difference between exposure and toxicity. Just as the containment of the snake in a glass cage does notInternal Draft Document Only; Do Not Cite, Quote or Release.

Page 42 of 56 change the fact that the snake’s venom is highly toxic, lack of exposure does not lessen the intrinsic toxicity of a chem ical. 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 to 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. 4), 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 t o, and immediately following, exposure to 0.05, 0.5, and 5.0 ppm hydrogen sulfide in separate sessions approximately one week apart. Commenters state that the sequence of exposures was randomly assigned to each subject and that the investigators reported that no significant changes were found between pre

- and post

- exposure performance, and that no dose

response was found in any of the neurobehavioral or neurosensory data sets. Commenters contend that although the exposures studied in the Fiedler et al. st udy 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 healt h effects. However, the commenters mistakenly reported no significant changes between pre

- and post

- exposure performance. This is inaccurate as theInternal Draft Document Only; Do Not Cite, Quote or Release.

Page 43 of 56 authors identified significant impairment of verbal learning in all exposure groups (p ! 0.0003). Althoug h 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 I ntent to L ift the S tay of the hydrogen sulfide reporti ng 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 relev ant 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 e ffects 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
Fede ral 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 exposu res 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 suggests, “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 a powerful molecular tool that is not available inInternal Draft Document Only; Do Not Cite, Quote or Release.

Page 44 of 56 human s tudies. These technologies provide powerful quantitative data, as evidenced in Skrajny et al. (1992) (Ref. 5). 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 belo w 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 adv erse 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 conc entrations of 5 ppm or below. Commenters cited the 2006 Schroeter et al. study (Ref. 6), 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. 7) 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 genera ted from magnetic resonance imaging (MRI) or computed tomography (CT) scan data. Commenters state that using allometrically equivalent breathing rates, the authors simulated steady

- state inspiratoryInternal Draft Document Only; Do Not Cite, Quote or Release.

Page 45 of 56 airflow and hydrogen sulfide uptake. Approximate locati ons 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 ai rflow, hydrogen sulfide 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 thes e 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 ty pe 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 mad e 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 theInternal Draft Document Only; Do Not Cite, Quote or Release.

Page 46 of 56 current RfC, it does not impact EPA’s assessment of the potential for hydrogen sulfide to cause chronic toxicity. The Agency doe s 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 exposu res and is not relevant to chronic effects. Further, the Schroeter reports only provide data for use in calculating the NOEAL

- HEC based o n 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 r eported 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 healthInternal Draft Document Only; Do Not Cite, Quote or Release.

Page 47 of 56 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 3 13 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 thi s 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 listi ng 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 thatInternal Draft Document Only; Do Not Cite, Quote or Release.

Page 48 of 56 hydrogen sulfide can cause are actually occurring in order to list it on EPCRA section 313. EPA notes that other commenter s 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 re leases 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 chemica l 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 f or 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 warr anted even though theInternal Draft Document Only; Do Not Cite, Quote or Release.

Page 49 of 56 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 re leases (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 whe ther 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, th at 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 sul fide 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 mod erate 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 expos ure 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 toxi city 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).Internal Draft Document Only; Do Not Cite, Quote or Release.

Page 50 of 56 As the D.C. Circuit noted, EPA stated that it would exercise its discretion by conside ring 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 d iscretion 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 fac ilities. 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 conten d 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 fa cilities 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 recom mended 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 repo rting of hydrogen sulfide as a by

- product of rendering operations.Internal Draft Document Only; Do Not Cite, Quote or Release.

Page 51 of 56 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 typi cal 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]ydroge n 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 ye ars 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 sulfi de 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), e xposure consideration is not appropriate for chemicals that have moderately high toInternal Draft Document Only; Do Not Cite, Quote or Release.

Page 52 of 56 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 rend ering process (Ref. 8). EPA has published emission factors for at least one stage of the rendering process (Ref. 9). 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 t hresholds (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 repor t. 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 rende ring and waste treatment processes and that the releases are fugitive,Internal Draft Document Only; Do Not Cite, Quote or Release.

Page 53 of 56 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

r eleases 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 comme nter 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 cons ider 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. 8). EPA has published emission factors for at least one stage of the rendering process (Ref. 9). The commenter believes that reporting would be difficult for hydrogen sulfide , yet the Na tional 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 m ost accurate information possible, EPCRA section 313 only requires that facilities report a reasonable estimate of releases. EPA sees no reason whyInternal Draft Document Only; Do Not Cite, Quote or Release.

Page 54 of 56 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 b y 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 d ocket, 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 phy sically 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; Communi ty Right

- to

- Know Toxic Chemical Release Reporting; Intent to consider lifting the administrative stay; opportunity for public comment. U.S. Environmental Protection Agency, Office of Environmental Information, Office of Information Analysis and Access. S eptember 30, 2010.
2. US EPA, 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 RiskInternal Draft Document Only; Do Not Cite, Quote or Release.

Page 55 of 56 Information Summary for Hydrogen Sulfide available at: http://www.epa.gov/ncea/iris/subst/0061.htm
4

. Fiedler N., Kipen H., Ohman

- Strickland P., Zhang J., Weisel C., Laumbach R., Kelly

- McNeil K., Olejeme K., and Lioy P., “Sensory and Cognitive Effects of Acute Exposure to Hydrogen Sulfide.” Env. Health Persp . v. 116(1), (2008), pp. 78

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driven computational fluid dynamics model to predict nasal extraction of hydrogen sulfide in rats and humans

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- 286. 8. Emission Factor Documentation for AP

- 42 Section 9.5.3 Meat Rendering Plants Final Report. Prepared by Midwest Research I nstitute (MRI) for the Office of Air Quality Planning and Standards (OAQPS), U. S. Environmental Protection Agency (EPA), under EPA
Contract No. 68

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. 9. AP 42, Fifth Edition, January 1995. Compilation of Air Pollutant Emission Facto rs, 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 (EP A).
List of Subjects in 40 CFR Part 372Internal Draft Document Only; Do Not Cite, Quote or Release.

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- know, Reporting and recordkeeping requirements, and Toxic chemicals Dated:_ XXX.. XX, 2010.

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_____________________________________ Lisa P. Jackson , Administrator

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