1

Response to Comments Received on the February 26, 2010, 

Federal Register Document (75 FR 8889):

Hydrogen Sulfide; Community Right-to-Know Toxic Chemical 

Release Reporting

Intent to consider lifting administrative stay; 

opportunity for public comment.

July 21, 2011

U.S. Environmental Protection Agency

Office of Information Analysis and Access

Ariel Rios Building

1200 Pennsylvania Ave., NW

Washington, DC 20460
2

Comment Number Commenter

EPA-HQ-TRI-2009-0844-0076 Shirley J. McNall 

EPA-HQ-TRI-2009-0844-0077 Eric Berg

EPA-HQ-TRI-2009-0844-0079 Amanda Buck

EPA-HQ-TRI-2009-0844-0081 Rita B. Messing , Minnesota Department of Health

EPA-HQ-TRI-2009-0844-0082 Hannah Connor, Waterkeeper Alliance 

EPA-HQ-TRI-2009-0844-0083 Wenonah Hauter, Food & Water Watch

EPA-HQ-TRI-2009-0844-0084 Anonymous public comment 

EPA-HQ-TRI-2009-0844-0086 David L. Meeker, National Renderers Association

EPA-HQ-TRI-2009-0844-0087 American Coke and Coal Chemicals Institute 

American Forest and Paper Association 

American Petroleum Institute 

Asphalt Institute 

Carbon Disulfide Coalition 

Corn Refiners Association 

National Petrochemical and Refiners Association 

The Sulphur Institute

EPA-HQ-TRI-2009-0844-0088 Natural Resources Defense Council

EPA-HQ-TRI-2009-0844-0089 Mary Johnson

EPA-HQ-TRI-2009-0844-0090 Cynthia A. Finley, National Association of Clean 

Water Agencies

EPA-HQ-TRI-2009-0844-0092 Linda Phillips

EPA-HQ-TRI-2009-0844-0093 Ashley B. Peterson, American Meat Institute

EPA-HQ-TRI-2009-0844-0094 Citizens for Environmental Justice

Community In-Powerment and Development Association

Northeast Ohio Gas Accountability Project

Sampson County Concerned Citizens For A Safe Environment

Air Alliance Houston

Cook Inletkeeper

Protect All Children’s Environment

Sustainable Energy & Economic Development Coalition

Texas Campaign for the Environment
3

Working Effectively for Clean Air Now

Downwinders at Risk

Person County People Rising In Defense of Ecology

Huron Environmental Activist League

Global Community Monitor

National Refinery Reform Campaign

National Bucket Brigade Coalition

Texas Oil and Gas Accountability Project

National Alliance for Drilling Reform

Wise County Alliance for Responsible Drilling

Groups Allied to Stop Pollution

OMB Watch

Sierra Club Lone Star Chapter

Environmental Integrity Project

Don’t Waste Arizona

EarthWorks

Oil & Gas Accountability Project

Citizens Against Environmental Destruction

Texas Environmental Justice Advocacy Services
4

Commenter: Shirley J. Mca11 [EPA-HQ-TRI-2009-0844-0076]

March 22, 2010

Office of Environmental Information (OEI) Docket

Environmental Protection Agency 1200 Pennsylvania Ave NW Washington, DC 20460

Subject: Docket ID No. EPA HQ-TRI-2009-0844

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

Comment:

To Whom It May Concern:

Please accept my comments into the official records as follows:

My name is Shirley J. McNall residing at 900 Sabena St. Aztec, New Mexico 87410. Our phone 

number is 505-334-6534

My husband and I live in a very large neighborhood in Aztec, NM. The population of Aztec is 

over 7,000 people. We live in the San Juan Basin of New Mexico "gas patch" among over 

20,000 gas wells. An additional 10,000 gas wells are scheduled to be drilled in our area in the 

next 20 years.

There are over 20 natural gas wells within half mile of our neighborhood. We know that at least 

5 of these gas wells are emitting unknown levels of hydrogen sulfide. Only two of these wells 

have hydrogen sulfide warning signs posted on the fences . We do not know how many more 

wells close to our home and neighborhood are emitting hydrogen sulfide. This is an unhealthy 

and dangerous fact known only by the oil and gas industry and possibly State and Federal 

Regulatory Agencies. It is a fact that every gas industry worker in the San Juan Basin is trained 

to deal with hydrogen sulfide and they are equipped with hydrogen sulfide monitors and have 

breathing safety equipment in their vehicles. The workers know which wells are hydrogen 

sulfide contaminated and have safety equipment available to them. We the people, who live next 

to these wells are kept in the dark about the presence and dangers of hydrogen sulfide. Most of 

the hydrogen sulfide gas wells are not posted and there is absolutely no public awareness 

information available to us. There are no emergency plans available to the residents of the San 

Juan Basin in case of hydrogen sulfide releases from the gas wells. We are "sitting ducks" . Our 

health and welfare is at risk 24/7 because of our daily exposure to hydrogen sulfide! !

I was personally impacted by the hydrogen sulfide emissions from one of the wells owned and 

operated by BP (BP Blanco Corn #2001 B - MV) which is a Federal Lease well and is located on 

State of New Mexico land less than a half mile from our home. My husband and I began to 

notice the strong smell of rotten eggs at our home every day beginning in early November, 2005. 

We were concerned that the odor was hydrogen sulfide, but we were not sure where it was 

coming from. On December 23, 2005, I walked to our newspaper box which is about 1000 feet 

from our house. I noticed the usual very strong rotten egg odor in the air. During my walk to the 

paper box, my throat became very sore, my eyes were watering, my face and lips felt numb and 
5

my legs became weak and wobbly. I struggled to walk back to the house. I was home alone and 

spent the rest of the day in bed suffering from an intense

Page 2 of Shirley J. McNall comments on Hydrogen Sulfide –

headache and sore throat . I later learned that my symptoms were those of hydrogen sulfide 

poisoning. I did not feel well for a few days, but did not know what was wrong with me. The 

strong odor of rotten eggs was still evident at our home every day. We determined that the rotten 

egg odor seemed to be more intense when the wind blew from the direction of the newly drilled 

BP Blanco Com well NE of our house. I was still suffering from headaches, sore throat, 

dizziness and muscle weakness whenever I went outside our home in our yard when the rotten 

egg odor was present.

On January 6, 2006, my husband and I noticed that the rotten egg odor was stronger than ever 

before . We called the New Mexico Oil Conservation Division and the local BP Office again! 

Two BP officials came to our house and determined that the odor was indeed hydrogen sulfide 

and they located the source which was the newly drilled BP Blanco Com well. They immediately 

shut the well off and later reported that the well had been treated "down hole" to neutralize the 

hydrogen sulfide. We did obtain the well report and were alarmed to learn that at one point the 

hydrogen sulfide content of that well was 196 parts per million! That level is far beyond the 

deadly level of hydrogen sulfide. Keep in mind that this well is less than a half mile of several 

hundred homes in the city of Aztec!

I live in constant fear that this well will "leak" hydrogen sulfide again. The BP officials told us 

that the well would be closely monitored and instructed us "to call them if we smell rotten eggs 

again". We have researched hydrogen sulfide and have found that at higher levels our olfactory 

nerves are desensitized and we might not smell anything. This is just not right !

Our health and our lives are at risk because of the presence of poorly managed natural gas wells 

emitting hydrogen sulfide in our neighborhood.

We are at additional risk because there is another BP well 2,400 feet from our home that is on 

Bureau of Land Management (BLM) Land and is on the BP/ BLM hydrogen sulfide well 

reporting list. The equipment on this well has malfunctioned numerous time and when it does, 

gas vapors including hydrogen sulfide permeates our neighborhood and inside our home. The 

most recent incident of "gassing" from this well was less than six months ago. We have no idea 

about the hydrogen sulfide levels in the other wells in our immediate neighborhood.

In December 2005, the BLM published a memo that stated that there are over 375 reports of gas 

wells in the San Juan Basin that are contaminated with hydrogen sulfide. The memo further said 

that the smaller companies did not report, so the number of hydrogen sulfide wells were likely 

much higher. I have a list of 193 hydrogen sulfide gas wells owned and operated by BP that are 

reported to the BLM on a regular schedule! ! There is no list of hydrogen sulfide wells located on 

private, State of NM, or tribal lands. The San Juan Basin gas field is old and more and more coal 

bed methane wells are being drilled which increases the presence of the dangerous and deadly 

hydrogen sulfide in our area. I strongly support the intent of the EPA to consider lifting the 
6

administrative stay of the reporting requirements for hydrogen sulfide. In addition, it is 

imperative that the EPA takes action to list hydrogen sulfide as a Hazardous Air Pollutant under 

the Clean Air Act. Thank you ~

Shirley J. Mca11 a survivor of hydrogen sulfide gassing) 900 Sabena Street, Aztec, NM 8

EPA Response: EPA appreciates the commenter’s support of the lifting of the administrative 

stay of the EPCRA section 313 reporting requirements for hydrogen sulfide.
7

Commenter: Eric Berg [EPA-HQ-TRI-2009-0844-0077]

Eric Berg 141 Bucks Mill Rd. Colts Neck, NJ 07722 ecberg@camden.rutgers.edu April 4, 2010

Office of Environmental Information (OEI) Docket Environmental Protection Agency Mail 

Code: 28221T 1200 Pennsylvania Ave., NW. Washington, DC 20460 

Comment:

To whom it may concern: 

I am writing to comment on the Environmental Protection Agency’s proposed 

rule regarding the reporting of hydrogen sulfide releases under the Emergency Planning 

and Community Right-to-Know Act (“EPCRA”).1 

Section 313 of EPCRA requires owners and operators of facilities subject to 

EPCRA’s requirements to complete a toxic chemical release form for each toxic chemical 

listed under subsection (c) or listed by the EPA Administrator under subsection (d). The 

Administrator may use the rulemaking process to add or delete chemicals by the list. 

Chemicals may be added if the Administrator determines that there is sufficient evidence 

to establish one of three criteria: 

(A) That “[t]he 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,” (the “acute human health effects criterion”); 

(B) “The chemical is known to cause or can reasonably be anticipated to cause in 

humans – cancer or teratogenic effects, or serious or irreversible reproductive 

dysfunctions, neurological disorders, heritable genetic mutations, or other chronic health 

effects,” (the “chronic human health effects criterion”); 

(C) “The chemical is known to cause or can reasonably be anticipated to cause, because 

of its toxicity... [and tendency to persist or]... bioaccumulate in the environment, a 

significant effect on the environment...” (the “environmental effects criterion”).2 

In 1993, hydrogen sulfide was added to the section 313 list of toxic chemicals. However, 

in 1994, the EPA issued an Administrative Stay of the reporting requirements for hydrogen 

sulfide “in order to evaluate issues brought to the Agency's attention after promulgation of the 

final rule concerning the human health effect basis for the listing and the Agency's use of 

exposure analysis in EPCRA section 313 listing decisions.”3The EPA reports that it has now 

completed this evaluation, and has come to the conclusion that the Administrative Stay should be 

lifted.4 

The EPA should lift the Administrative Stay. Hydrogen sulfide is a toxic substance that 

is clearly harmful to human health. At 0.0047 parts per million (ppm), humans can smell 
8

hydrogen sulfide’s characteristic odor, commonly described as a “rotten egg” smell.5 Hydrogen 

sulfide levels in the range of 500-1,000 ppm are acutely 

life-threatening.6 Recognizing its deadliness, the British briefly used hydrogen sulfide as a 

chemical weapon during World War I.7 

Hydrogen sulfide can also cause chronic toxicity, affecting both the neurological and 

respiratory systems.8Long-term, irreversible neurological effects can result from high exposure 

episodes. Nasal tract lesions and neurological effects can occur with exposure levels as low as 20 

to 30 ppm.9 Finally, the EPA also has sufficient evidence to believe that “has also been 

determined to cause ecotoxicity at relatively low concentrations, and thus is considered to have 

high ecotoxicity.”10Hydrogen sulfide thus satisfies all three of the section 313(d)(2) criteria for 

addition to the EPCRA toxic chemical release reporting list. 

The public has a statutory right to know when a harmful chemical of this nature is 

released by the owner or operator of a polluting facility. Under both the letter and the spirit of 

EPCRA, releases of hydrogen sulfide should be reported under section 313. 

Sincerely, Eric Berg Candidate for J.D., May 2011 Rutgers School of Law-Camden 

1

Hydrogen Sulfide; Community Right-to-Know Toxic Chemical Release, 40 C.F.R. § 372, Docket ID # EPAHQ-TRI-2009-0844 (2010). 2

Emergency Planning and Community Right-to-Know Act of 1986, § 313, 42 U.S.C. § 11023; Hydrogen

Sulfide; Community Right-to-Know Toxic Chemical Release, 40 C.F.R. § 372, Docket ID # EPA-HQ-TRI2009-0844 (2010). 3

Id. 4

Id. 5

The Science of Smell Part 1: Odor perception and physiological response, 

http://www.extension.iastate.edu/Publications/PM1963A.pdf (accessed Apr. 4, 2010). 

6

Hydrogen Sulfide; Community Right-to-Know Toxic Chemical Release, 40 C.F.R. § 372, Docket ID #

EPA-HQ-TRI-2009-0844 (2010). 7 

While not as effective as other chemical weapons, hydrogen sulfide was used on two occasions when

other gases were in short supply. See Charles Howard Foulkes, "Gas!" The Story of the Special Brigade

105 (Naval & Military P. ed. 2001) (1934). 

8

Hydrogen Sulfide; Community Right-to-Know Toxic Chemical Release, 40 C.F.R. § 372, Docket ID #

EPA-HQ-TRI-2009-0844 (2010). 9

Id. 10

Id.

EPA Response: EPA appreciates the commenter’s support of the lifting of the administrative 

stay of the EPCRA section 313 reporting requirements for hydrogen sulfide.
9

Commenter: Amanda Buck [EPA-HQ-TRI-2009-0844-0079]

PUBLIC SUBMISSION

As of: May 17, 2010

Received: April 13, 2010

Status: Posted

Posted: April 15, 2010

Tracking No. 80ad671a

Comments Due: April 27, 2010

Submission Type: Web

Docket: EPA-HQ-TRI-2009-0844

Hydrogen Sulfide; Methyl Mercaptan; Toxic Chemicals Right-to-Know; Stay of Reporting 

Requirements [400088]

Comment On: EPA-HQ-TRI-2009-0844-0021

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

Document: EPA-HQ-TRI-2009-0844-0079

Comment submitted by A. Buck

Submitter Information

Submitter's Representative: Amanda Buck

General Comment

Comment:

As a member of the scientific community, I am aware of the hazards of Hydrogen Sulfide 

exposure, and am capable to take the appropriate precautions to reduce my risk. My main 

concern/comment revolves around a question: why did it take more than 15 years for the Stay to 

be lifted? Also, what were the restrictions surrounding such a lengthy process: time, money, 

man-power? I thank you for your consideration.

EPA Response: The delay in taking action on the administrative stay of the EPCRA section 313 

reporting requirements was a combination of competing actions, resources, and administration 

priorities.
10

Commenter: Minnesota Department of Health (MDH) [EPA-HQ-TRI-2009-0844-0081]

April 29, 2010 

Office of Environmental Information (OEI) Docket 

Environmental Protection Agency (EPA) 

www.regulations.gov

Re: EPA Docket ID No. EPA-HQ-TRI-2009-0844 

Comment:

To whom it may concern: 

The Minnesota Department of Health (MDH) is pleased to submit comments responding the U.S. 

Environmental Protection Agency (EPA) Intent to Consider Lifting Administrative Stay for 

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

Register Volume 75, Number 38, February 26, 2010). 

The U.S. Congress required chemical release reporting in Section 313 of the Emergency 

Planning and Community Right-to-Know Act (EPRCA). As EPA notes, reporting requirements 

for hydrogen sulfide (H2S) were listed in the final rule (December 1, 1993), but an 

Administrative Stay was granted on August 22, 1994 so that EPA could further evaluate human 

health and environmental effects. MDH urges EPA to lift the stay because of extensive and 

increasing evidence that community exposures to H2S adversely affect public health. Further, 

MDH urges EPA to extend reporting requirements to include large Concentrated Animal Feeding 

Operations (CAFOs). 

In support of lifting the stay, EPA cites the authoritative review provided in its Integrated Risk 

Information System (IRIS; EPA 2003) of human health effects, including long-lasting 

neurological effects, resulting from exposures to acute high levels of H2S. Of even greater 

importance for continuing releases and exposures, EPA cites the IRIS review of research 

indicating nasal lesions in olfactory mucosa observed in sub-chronic studies in adult rats and 

mice, neurochemical changes in the cerebellum and frontal cortex in neuro-developmental 

studies of rats, and changes in the micro-anatomy of the cerebellum in neuro-developmental rat 

studies. EPA notes that effects occur at H2S levels as low as 20 to 30 ppm (28 to 42 mg/m3). 

These sub-chronic and neuro-developmental findings are worth considering in more detail. First, 

IRIS provides corrections for partial day exposures and for differences in the rat and human 

respiratory systems, to arrive at a Human Equivalent Concentration (HEC) for continuing 

exposures. In the sub-chronic critical study used by IRIS, animals were exposed 6 hours/day, 7 

days a week for 10 weeks. Thus, to adjust for partial days, 30 ppm must be divided by 4, to 

arrive at a concentration of 7.5 ppm for nasal lesions for continuous exposure over 10 weeks. To 

extrapolate to humans for a gas respiratory effect in the extra-thoracic region, IRIS arrived at a 

Human Equivalent Concentration of 1.9 ppm (LOAELHEC). No effect was observed in this 

study at 10 ppm, so the No Observed Adverse Effects Level—HEC (NOAELHEC) for this study 
11

is 0.64 ppm. 

The finding of toxicity as low as 2 ppm HEC is consistent with studies of humans discussed by 

the Agency for Toxic Substances and Disease Registry (ATSDR) (2006). ATSDR cites evidence 

that exposure to healthy volunteers to short-term exposures as low as 5 ppm resulted in increases 

in blood lactate concentrations and decreases in muscle citrate synthase activity indicative of 

inhibition of aerobic exercising muscle capacity (Bhambini and Singh 1991). ATSDR also notes 

that short-term exposure of asthmatics to H2S results in increased airway resistance in some 

subjects, indicative of bronchial obstruction (Jappinen et al. 1990). 

Neither the animal or human studies address long-term or repeated exposures to hydrogen 

sulfide. However, ATSDR has also cited community studies documenting effects when there are 

repeated exposures in the low ppb range. Campagna et al. (2004) found that following days when 

H2S levels were above 30 ppb in a Nebraska community, there was an increase in asthma-related 

hospital visits among adults and children. Kilburn and Warshaw (1995) found that people 

working at oil processing plants or living downwind experienced nausea, headache, vomiting, 

breathing abnormalities, nosebleeds, depression and personality changes at levels of H2S

between 10 ppb and 100 ppb. 

These community studies are consistent with the American Industrial Hygiene Association 

(AIHA) Emergency Response Planning Guideline-1 (ERPG-1) of 100 ppb for H2S. The AIHA 

considers this a maximum airborne concentration below which it is believed that nearly all 

individuals could be exposed for up to 1 hour without experiencing other than mild, transient 

adverse health effects or without perceiving a clearly defined objectionable odor. However, the 

ERPGs are used for guiding emergency response planning, and are meant for only one-time or 

rare exposures. Repeated exposures to communities at these levels, such as those reviewed by 

ATSDR, are deleterious to public health. 

ATSDR and MDH recently published a Health Consultation for the Excel Dairy in Thief River 

Falls, Minnesota (ATSDR/MDH, 2009) documenting over 400 half hour periods in which air 

concentrations of H2S at the facility boundary were over 30 ppb (the Minnesota Ambient Air 

Quality Standard for H2S not to be exceeded more than twice in 5 days) from May to October of 

2008. Over 100 periods were measured above 90 ppb (the maximum reading from Minnesota 

Pollution Control Agency (MPCA) continuous air monitoring equipment). Peak readings over 

400 ppb were obtained by ATSDR at peoples’ residences, and over 30 periods above the ATSDR 

short term Minimum Risk Level of 70 ppb were measured at two residences during a two week 

period in July 2008. ATSDR and MDH declared the Excel Dairy to be a Public Health Hazard

and recommended that rapid, permanent and efficacious measures be taken to alleviate these 

conditions. 

Taken together, these findings suggest that repeated continuing exposures to H2S between 30 and 

100 ppb are stressful for communities and are a public health hazard. For this reason, MDH 

believes that it is important for EPA to lift the Administrative Stay of Toxic Release Inventory 

(TRI) reporting so that communities will be provided with information about H2S releases in 

their communities. 
12

EPA Response: The commenter has provided a summary of the derivation of the Human 

Equivalency Concentration (HEC) calculation found in the IRIS evaluation of hydrogen sulfide 

(IRIS; EPA 2003) based on the data of Brenneman et al. (2000). There exists a unit conversion 

error in this commenter’s description of the IRIS LOAELHEC and NOAELHEC calculations such 

that these values are represented as 1.9 ppm and 0.64 ppm, respectively. The proper values 

should be 1.9 mg/M3 (1.38 ppm) and 0.64 mg/M3 (0.46 ppm), respectively, as detailed in the 

IRIS document. Although this error exists, the subsequent comments regarding the comparison 

of HECs and the human studies discussed in ATSDR (2006) remain pertinent.

 

The Agency would also like to thank this commenter for bringing additional research 

reports to our attention. The peer-reviewed report by Campagna et al. (2004) in the Journal of 

Exposure Analysis and Environmental Epidemiology details a positive association between 

hospital visits for asthma and the previous day ambient air hydrogen sulfide levels in a 

Nebraskan population. In addition, a positive association was identified between children’s 

hospital visits for respiratory disease and the previous day ambient hydrogen sulfide levels. 

Given the lack of human health dose-response studies, epidemiologic studies become an 

important resource for evaluating chemical hazards.

Comment:

Furthermore, as the Minnesota experience with the Excel Dairy illustrates, it is also important 

that EPA extend the TRI reporting requirements to CAFOs. In 2008 the Excel Dairy was 

permitted to house 1,100 dairy cows weighing over 1,000 pounds. Liquid manure from the barns 

was pumped into three uncovered waste basins. As noted above, air levels of H2S emanating 

from this facility have been declared a Public Health Hazard by MDH and ATSDR. Furthermore, 

the MPCA has noticed an intent to deny reissuance of the Excel Dairy permit. 

EPA (2001) has estimated that 0.051 pounds per day of sulfur may be excreted by a lactating 

dairy cow. The Michigan Department of Environmental Quality (2009) estimates that 0.05 

pounds of hydrogen sulfide per day could be emitted in the summer and about a tenth that 

amount in the winter. These emissions factors suggest that between 10,000 to over 20,000 

pounds per year of hydrogen sulfide could be emitted by a Dairy CAFO the size of Excel. Some 

Dairy CAFOs may have 5,000 or more cows according to EPA (2001) and may therefore emit 

proportionately more H2S. EPA (2001) also suggested emissions factors for other livestock and 

poultry. These factors indicate that large CAFOs, especially large swine CAFOs, may emit 

quantities of H2S of health concern for surrounding communities. Communities need to be 

informed of potential emissions, and resulting air concentrations of H2S so that appropriate steps 

can be taken to protect public health. 

In summary, MDH strongly supports lifting the administrative stay for Hydrogen Sulfide, 

Community Right-to-Know Toxic Chemical Release Reporting, and also urges EPA to extend 

reporting to CAFOs. These actions are important steps for empowering communities to protect 

themselves from adverse health effects resulting from exposures to hydrogen sulfide. 

Sincerely, 

 
13

Rita B. Messing, Ph.D., Toxicologist 

Supervisor, Site Assessment and Consultation 

Project Director, ATSDR Program to Conduct and Coordinate Site-Specific Activities 

Cc: Gaylen Reetz, Director, Regional Division, MPCA 

Rick Strassman, Supervisor, Air Quality Monitoring, MPCA 

Mark Johnson, ATSDR Senior Region 5 Representative 

Alan Yarbrough, Site-Specific Activities Cooperative Agreement Lead, ATSDR 

References: 

AIHA. Emergency Response Planning Guidelines. 

http://www.aiha.org/foundations/GuidelineDevelopment/ERPG/Pages/default.aspx

ATSDR, 2006. Toxicological Profile for Hydrogen Sulfide. 

http://www.atsdr.cdc.gov/toxprofiles/index.asp

ATSDR/MDH, 2009. Health Consultation: Excel Dairy, Excel Township, Marshall Co. 

Minnesota. 

http://www.health.state.mn.us/divs/eh/hazardous/sites/marshall/exceldairy/index.html

Bhambhani Y and Singh M., 1991. J. App. Physiol. 71(5):1872-1877. 

Campagna, D. et al., 2004. J. Exp. Anal. & Env. Epi. 14:180-187. 

EPA, 2001. Emissions from Animal Feeding Operations, Draft. Emissions Standards Division. 

Office of Air Quality Planning and Standards. Research Triangle Park, NC: EPA 

Contract No. 68-D6-0011, Task Order 71. 

http://www.epa.gov/ttn/chief/ap42/ch09/draft/draftanimalfeed.pdf

EPA, 2003. IRIS file for Hydrogren Sulfide. http://www.epa.gov/ncea/iris/subst/0061.htm

Jappinen, P. et al., 1990. Br. J. Ind. Med. 47:824-828. 

Michigan Dept. of Environmental Quality, 2009. Dairy Emissions Worksheet. 

www.michigan.gov/documents/deq/deq-ess-cafo-worksheetdairyemissions_266406_7.pdf - 2009-02-13

EPA Response: EPA appreciates the commenter’s support of the lifting of the administrative 

stay of the EPCRA section 313 reporting requirements for hydrogen sulfide. With regard to the 

addition of Concentrated Animal Feeding Operations (CAFOs) to the list of industry sectors that 

report under EPCRA section 313, EPA is currently evaluating additional industry sectors for 

possible addition.
14

Commenter: Waterkeeper Alliance [EPA-HQ-TRI-2009-0844-0082]

VIA REGULATIONS.GOV

May 06, 2010

U.S. Environmental Protection Agency

Office of Environmental Information Docket

Mailcode: 28221T

1200 Pennsylvania Ave., NW

Washington, D.C. 20460

Re: Intent to Consider Lifting Administrative Stay of Hydrogen Sulfide

Reporting; Docket No. EPA-HQ-TRI-2009-0844

These comments are submitted by Waterkeeper Alliance (“Waterkeeper”) in support of lifting 

the administrative stay of the toxic chemical release reporting requirements for hydrogen sulfide 

under section 313 of the Emergency Planning and Community Right-to-Know Act (“EPCRA”).

Waterkeeper Alliance, Inc. is a non-profit organization representing the interests of 195 member 

watershed groups. Each of these groups and their members have the express mission to preserve 

and protect local waterbodies for aesthetic, recreational, and other purposes. Waterkeepers 

combine firsthand knowledge of their waterways with an unwavering commitment to the rights 

of their communities and to the rule of law. As it relates to this action, Waterkeeper is 

exceedingly concerned with the human health and environmental effects of hydrogen sulfide.

BACKGROUND

Over sixteen years ago, on December 1, 1993, the United States Environmental Protection 

Agency (“EPA”) added hydrogen sulfide to the EPCRA Toxics Release Inventory (the “TRI” or 

“313”) list of toxic chemicals. EPCRA section 313 requires authorities to annually collect data 

on releases and transfers of listed toxic chemicals and to make that data available to the public in 

the TRI.1 “The goal of TRI is to empower citizens, through information, to hold companies and 

local governments accountable in terms of how toxic chemicals are managed.”2 Accordingly, 

any facility that manufactures, processes or otherwise uses a listed chemical(s) in an amount 

above the reportable quantity must report its environmental releases in an annual TRI report.

To ensure appropriate realization of these goals and purposes, in adding a chemical to the TRI 

list EPA must demonstrate that the chemical meets at least one of the criteria listed in ECRCA 

Section 313(d)(2). As it pertains to hydrogen sulfide, EPA based its original

TRI listing decision on two criteria. First, EPA found that hydrogen sulfide can cause

chronic impacts to human health due to its neurotoxic nature.3 Second, EPA found that 

hydrogen sulfide can produce environmental impacts by, among other ways, causing acute 

aquatic toxicity.4
15

However, on August 22, 1994, EPA issued an administrative stay of the EPCRA 313 reporting 

requirements for hydrogen sulfide. This administrative stay did not remove hydrogen sulfide 

from the TRI list; it merely deferred the reporting requirements for hydrogen sulfide until a few 

additional assessments could be conducted. In short, those assessments focused on the 

supplementation of the Agency’s evaluation of the human health effect basis for listing hydrogen 

sulfide.

On February 26, 2010, EPA proposed lifting the administrative stay for hydrogen sulfide 

reporting under EPCRA section 313. If finalized, communities will at last be provided with the 

fundamental information regarding the sources and quantities of hydrogen sulfide being released 

in their ambient environments. Given that hydrogen sulfide is a highly pernicious chemical, 

communities deserve to know the degree to which this chemical is being released, and the 

opportunity to protect themselves against the resulting preventable harm.

ABOVE REPORTABLE QUANTITIES, HYDROGEN SULFIDE EXPOSURE IMPAIRS 

HUMAN HEALTH AND THE ENVIRONMENT

Comment:

Technical evaluation of hydrogen sulfide shows that is can reasonably be anticipated to cause 

chronic and hazardous impacts to human health and the environment. EPA has compiled a 

sufficient record to support this determination.

Human Health Effects of Hydrogen Sulfide 

As stated in EPA’s Notice of Intent to Consider Lifting the Administrative Stay for Hydrogen 

Sulfide (“Notice”) and as further detailed in EPA’s most recent Integrated Risk Information 

System (“IRIS”) Toxicological Review of Hydrogen Sulfide,

[h]hydrogen sulfide is a colorless, acutely toxic gas at high concentrations. 

Hydrogen sulfide gas is absorbed rapidly through the lungs and can be absorbed 

through the gastrointestinal tract. Oral exposure is not likely to occur. In animals

and humans, it distributes to the blood, brain, lungs, heart, liver, spleen, and 

kidneys. Oxidation is the primary metabolic pathway for hydrogen sulfide....A 

considerable body of case studies exists on the human health impacts resulting

from acute exposure to high levels of hydrogen sulfide. Levels in the range of 500

to 1,000 parts per million (ppm)...are life-threatening and can cause immediate 

unconsciousness followed by serious and debilitating neurologic and respiratory

sequelae and death. While complete recovery from a high exposure episode has been 

reported, more often long term or even irreversible harmful neurologic effects remain.5

Of the numerous persistent, adverse neurological effects that could result from acute exposure to 

hydrogen sulfide, brain damage is one of the most studied. Brain damage is believed to result 

from the “essentially hypotoxic”6 condition that occurs when people who are exposed to high 

levels of hydrogen sulfide are not able to inhale a sufficient amount of oxygen. Without oxygen, 

the brain tissue cannot sustain itself and will result in neuronal impairment and cell death. The 
16

longer the human body is deprived of an adequate supply of oxygen, the more damage that will 

occur.

For example,

[t]he observed nonirritant effects produced in mammals from exposure to hydrogen 

sulfide gas may primarily be attributed to the cellular anoxia produced by inhibition of 

cytochrome oxidase....Hence, cells with a high oxygen demand, such as those in brain and 

cardiac tissue are thought to be more sensitive to disruption of oxidative metabolism and may be 

considered selected targets for the toxicity of hydrogen sulfide.7

Based on these and numerous other findings and studies, EPA determined that hydrogen sulfide 

exposure can impact human health in two principal manners. First, exposure can produce 

chronic respiratory problems, including nasal tract lesions; second, exposure can result in 

irreversible and adverse neurological effects. “These effects occur in a clear dose concentration 

manner with the lowest level of hydrogen sulfide exposure associated with these effects ranging 

from 20 to 30 ppm.”8 Due to these effects, EPA believes that hydrogen sulfide meets the 

requirements of EPCRA section 313.

EPA Response: The Agency concurs with this commenter’s summation of the human health 

effects associated with hydrogen sulfide. 

Comment:

Environmental Impacts of Hydrogen Sulfide 

In support of its determination that hydrogen sulfide exposure can impact the environment, EPA 

explains that, “[a] number of ecotoxicity studies have been conducted on hydrogen sulfide, 

mainly on freshwater invertebrates and fish. Acute, chronic, and early-stage toxicity values for 

hydrogen sulfide include numerous values that are well below 1 milligram per liter (mg/L), 

indicating that hydrogen sulfide is toxic at very low concentrations.”9 Upon analysis of these 

and numerous other studies, EPA determined that hydrogen sulfide can reasonably be anticipated 

to cause serious and possibly irreversible damage to the environment. As a result, hydrogen 

sulfide also meets the requirements of EPCRA section 313.

EPA Response: The Agency concurs with this commenter’s summation of the environmental 

impacts associated with hydrogen sulfide. 

Comment:

WATERKEEPER SUPPORTS THE LIFTING OF THE ADMINISTRATIVE STAY FOR 

HYDROGEN SULFIDE REPORTING UNDER SECTION 313 OF EPCRA 

After a reasoned evaluation of the environmental and human health hazards of hydrogen sulfide 

exposure, EPA determined “that there is no basis for continuing the Administrative Stay of the 
17

reporting requirements for hydrogen sulfide” and supports a lifting of the stay.10 Waterkeeper 

believes that EPA’s decision to lift this administrative stay is supported by the record, and that it 

is in the best interest of human health and the environment. Accordingly, we support the lifting 

of the administrative stay of toxic chemical release reporting requirements for hydrogen sulfide 

under section 313 of EPCRA by the EPA.

Sincerely,

Hannah Connor

Waterkeeper Alliance

1 See 42 U.S.C. § 11023. 

2 United States Environmental Protection Agency, What is the Toxics Release Inventory (TRI) Program, 

http://www.epa.gov/tri/triprogram/whatis.htm (last visited May 05, 2010).

3 See 42 U.S.C. § 11023 (d)(2)(B); 75 Fed. Reg. 8889, 8891 (Feb. 26, 2010).

4 See 42 U.S.C. § 11023 (d)(2)(C); 75 Fed. Reg. at 8891.

5 75 Fed. Reg. at 8891.

6 Id.

7 Id. at 8892

8 Id. at 8893. 9 Id.

10 Id.

EPA Response: EPA appreciates the commenter’s support of the lifting of the administrative 

stay of the EPCRA section 313 reporting requirements for hydrogen sulfide.
18

Commenter: Food & Water Watch [EPA-HQ-TRI-2009-0844-0083]

May 11, 2010 

EPA Docket Center (EPA/DC) 

EPA West, Room 3334 

1301 Constitution Ave. NW 

Washington, DC 20460 

Re: Docket ID # EPA–HQ–TRI–2009–0844 

To Whom It May Concern: 

Comment:

Food & Water Watch, a national nonprofit consumer advocacy organization, supports the 

Environmental Protection Agency’s proposal to lift the administrative stay of section 313 of the 

Emergency Planning and Community Right--‐to--‐Know Act (EPCRA), the toxic chemical 

release reporting requirements for hydrogen sulfide (Docket ID # EPA–HQ–TRI–2009– 0844.) 

The basis that EPA has used to determine that hydrogen sulfide is dangerous to human health 

and the environment is reasonable. Lifting the administrative stay is vitally important, as it is not 

unusual for hydrogen sulfide releases from concentrated animal feeding operations to occur at 

levels demonstrated by EPA studies to cause dangerous health effects in humans. Given EPA's 

non--‐enforcement of air releases from CAFOs through the Clean Air Act Compliance 

Agreement, as well as the recent exemption of small and medium--‐sized CAFOs from 

CERCLA/EPCRA reporting requirements, the monitoring and publishing of dangerous releases 

of hydrogen sulfide from large CAFOs is a long overdue first step in ensuring the health and 

safety of rural communities where these facilities are located. 

EPCRA’s stated purpose is to “inform the general public and the communities surrounding 

covered facilities about the releases of toxic chemicals . . ..”i Concentrated animal feeding 

operations, or CAFOs, are responsible for the release of significant amounts of toxic chemicals 

into the air each day. The two most hazardous chemicals emitted from CAFOs are ammonia and 

hydrogen sulfide, and they are emitted in concentrations that are potentially harmful to nearby 

residents.ii Communities surrounding CAFOs deserve to know what is being emitted from these 

facilities, particularly when chemicals like hydrogen sulfide are released in dangerous amounts. 

As the EPA toxicology review of hydrogen sulfide demonstrates, hydrogen sulfide is a toxic 

chemical that can cause a variety of health problems when overexposure occurs, ranging from 

dizziness, nausea, and headaches, to complete physical collapses, respiratory failure, hypoxia, 

and death.iii Hydrogen sulfide releases from CAFOs have been credited with excessive diagnoses 

of respiratory and digestive disturbances, and hydrogen sulfide and 2 ammonia emissions from 

CAFOs have been linked to asthma, bronchitis, and other respiratory diseases in facility 

workers.iv

In 2003, the University of Iowa and Iowa State University performed an extensive and thorough 

study on the air quality impacts of concentrated animal feeding operations, including the impacts 
19

of hydrogen sulfide releases. Hydrogen sulfide can cause adverse health effects in concentrations 

as low as 10 parts per million (ppm),v and can be life threatening at levels of 500 ppm.vi

Emissions from CAFOs were shown to exceed lethal levels under certain circumstances. In 

liquid manure holding pits, which are common for swine CAFOs, releases of hydrogen sulfide 

can be at concentrations of 1000 ppm or higher when waste from the lagoons is agitated prior to 

being pumped out of the facility.vii 

While hydrogen sulfide has a strong rotten egg--‐like smell at lower concentration levels, the 

intensity of the smell does not increase significantly with higher levels of exposures. In fact, at 

levels that become dangerous to human health (above 150 ppm), the intensity of the smell of 

hydrogen sulfide actually decreases.viii The EPA toxicological review of hydrogen sulfide 

recognized that the rotten--‐egg odor is an “inadequate warning indicator of exposure since 

levels in the range of 100--‐200 ppm (140--‐280 mg/m3) can lead to loss of smell followed by 

olfactory paralysis.”ix Since this level is indeed above that which can be emitted from CAFOs, 

workers at these facilities and nearby residents would have no way of knowing whether they are 

in danger based on the smell alone, therefore the reporting of emissions of hydrogen sulfide in 

excess of EPCRA limits is essential in providing community members the information they need 

to protect their health. 

Based on two prior agency actions, the EPA has shown that it has been unwilling to regulate air 

emissions from CAFOs. In 2005, EPA made a sweetheart deal with the CAFO industry with its 

Clean Air Act Compliance Agreement. In exchange for a nominal fee, CAFO operators were 

released from liability, and their emissions were to be monitored in order to provide the EPA 

with information that would supposedly allow the agency to promulgate regulations on emissions 

under the Clean Air Act.x The study was to be completed in 2009, but as of yet, EPA has 

released zero information to the public regarding the study and has not made any progress in the 

rulemaking process. Five years after the compliance agreement was first announced, there is still 

no information from the EPA on the amount of harmful emissions that are coming out of 

CAFOs. In addition, those CAFOs participating in the Air Compliance Agreement are virtually 

exempt from EPCRA reporting requirements for ammonia (and presumably hydrogen sulfide) as 

well.xi 

EPA's second gift to the CAFO industry occurred in 2008 when the agency chose to exempt 

small and medium--‐sized CAFOs from EPCRA reporting requirements.xii Large CAFOs are still 

required to report emergency emissions under EPCRA section 304.xiii Even if the administrative 

stay on EPCRA reporting of hydrogen sulfide releases is lifted, there will still be no information 

available on any potentially deadly releases of hydrogen sulfide from small and medium--‐sized 

CAFOs into their communities. This is completely unacceptable, and is further example of EPA 

shirking its duties under the Clean Air Act. 

With EPA’s failure to regulate the air emissions from CAFOs under the Clean Air Act, EPCRA 

is the only option left that citizens in communities surrounding CAFOs have for finding out what 

hazardous substances are actually being emitted into the air. As the research has shown, 

hydrogen sulfide is a very real and dangerous threat from Concentrated Animal Feeding 

Operations. Large CAFOs that are not exempt from reporting requirements should be required to 

report their emissions of hydrogen sulfide that are in excess of CERCLA/EPRCA limits. Food & 
20

Water Watch supports EPA's proposal to end the administrative stay on reporting requirements 

for hydrogen sulfide. 

Thank you for your consideration of these comments. 

Sincerely, 

Wenonah Hauter 

Executive Director 

i 40 CFR § 372.1 (2009).

ii Iowa State University and the University of Iowa Study Group. “Iowa Concentrated Feeding Operations

Air Quality Study.” February 2002 at 6.

iii U.S. Environmental Protection Agency. “Toxicological review of hydrogen sulfide.” CAS No. 778-06-4.

June 2003 at 10.

iv Donham, Kelly J., et al. “Community health and socioeconomic issues surrounding concentrated animal

feeding operations.” Environmental Health Perspectives, vol. 115, iss. 2. February 2007 at 317-318.

v Sweeten, John M., et al. Confined Livestock Air Quality Committee of the USDA Agricultural Air Quality

Task Force. “Air quality research and technology transfer white paper and recommendations for

concentrated animal feeding operations.” July 19, 2000 at 14.

vi U.S. Environmental Protection Agency. “Toxicological review of hydrogen sulfide.” CAS No. 778-06-4.

June 2003 at 51-52.

vii Iowa State University and the University of Iowa Study Group. at 118, 124.

viii Iowa State University and the University of Iowa Study Group. at 124.

ix U.S. Environmental Protection Agency. “Toxicological review of hydrogen sulfide.” CAS No. 778-06-4.

June 2003 at 10.

x U.S. Environmental Protection Agency. "Thousands sign up for animal feeding operations air

compliance agreement." Press release. August 15, 2005.

xi U.S. Environmental Protection Agency. "CERCLA/EPCRA Administrative Reporting Exemption for Air

releases of hazardous substances from animal waste at farms." Fact Sheet. February 2009.

xii 73 Fed. Reg. 76948, 76950, (Dec. 18, 2008).

xiii 73 Fed. Reg. 76948, 76950, (Dec. 18, 2008).

EPA Response: EPA appreciates the commenter’s support of the lifting of the administrative 

stay of the EPCRA section 313 reporting requirements for hydrogen sulfide. With regard to the 

addition of Concentrated Animal Feeding Operations (CAFOs) to the list of industry sectors that 

report under EPCRA section 313, EPA is currently evaluating additional industry sectors for 

possible addition. 
21

Commenter: Anonymous [EPA-HQ-TRI-2009-0844-0084]

PUBLIC SUBMISSION

As of: May 17, 2010

Received: May 12, 2010

Status: Posted

Posted: May 13, 2010

Tracking No. 80aeb8b5

Comments Due: May 12, 2010

Submission Type: Web

Docket: EPA-HQ-TRI-2009-0844

Hydrogen Sulfide; Methyl Mercaptan; Toxic Chemicals Right-to-Know; Stay of Reporting

Requirements [400088]

Comment On: EPA-HQ-TRI-2009-0844-0078

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

Comment Period

Document: EPA-HQ-TRI-2009-0844-0084

Anonymous public comment

Submitter Information

General Comment

Comment:

Hydrogen sulfide has the potential to be an extremely toxic substance. While it can often be 

found as a naturally occurring compound in swampy areas or even in small amounts produced by 

the human body, it can be lethal in larger amounts. Long term exposure is also detrimental. 

These are obvious facts that can be procured in a basic Chemistry class and yet there is an 

administrative stay in place that says that there does not need to be any reporting on levels of 

hydrogen sulfide. While I can understand the rationale, there needs to be steps taken to protect 

the public. Obviously there is not much that can be done in order to quell the effects of naturally 

produced hydrogen sulfide, but we can control industrial production and require companies to 

report the figures.

I fully commend you on this regulation that would lift the administrative stay. I find that the fact 

that states that hydrogen sulfide was added to a list of toxic chemicals in 1993 to be perhaps the 

largest determining factor in lifting the stay as well as the effects on the human body. Also, if 

you take a look at the effect that hydrogen sulfide, in quantities greater than what is naturally 

found, could have upon our ecosystem then we, as the public, certainly have the right to know. 

Even if hydrogen sulfide was only toxic to, say, fish or even livestock, then we are still posing 

the danger that hydrogen sulfide could cause some form a genetic mutation which could be 

harmful to humans that ingest the food. There are way too many possibilities out there and too 

much information available to uphold the administrative stay. It’s time we lift it and provide the 

public with their right to the knowledge.

EPA Response: EPA appreciates the commenter’s support of the lifting of the administrative 

stay of the EPCRA section 313 reporting requirements for hydrogen sulfide. 
22

Commenter: National Renderers Association [EPA-HQ-TRI-2009-0844-0086]

May 12, 2010 

Environmental Protection Agency EPA Docket Center (EPA/DC) ID No. EPA–HQ–TRI–2009–

0844 1200 Pennsylvania Avenue, NW Washington, DC 20460 

RE: Hydrogen Sulfide; Community Right-to-Know Toxic Chemical Release 

Inventory Reporting (TRI) 

The National Renderers Association (NRA) is the international trade association for the industry 

that safely and efficiently recycles animal agriculture by-products into valuable ingredients for 

the livestock, pet food, chemical and consumer product industries in a manner that is protective 

of our environment. NRA represents its members’ interests to Congress, regulatory and other 

government agencies, promotes greater use of rendered products, and fosters the opening and 

expansion of trade between North American exporters and foreign buyers. NRA’s membership 

represents more than 98 percent of the rendering capacity in both the U.S. and Canada, and we 

estimate that our members have spent more than $100 million in recent years on environmental 

controls that help protect the environment where we live and work. 

Comment:

We do not support listing hydrogen sulfide emissions from rendering plants under the EPCRA 

regulations because of the extremely low level of hydrogen sulfide potentially emitted from 

rendering plant operations. These emissions are likely to be well below levels of concern for 

human health and the environment. We agree 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. These potentially harmful concentrations are

well understood, published, and regulated under OSHA and NIOSH standards that we are 

required to comply with as part of facility operations. There are levels of exposure to hydrogen 

sulfide that can be considered safe and the fence-line concentration of hydrogen sulfide at a 

typical rendering plant would be expected to be well below a “safe” level. Therefore, we 

recommend that EPA’s evaluation 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 reporting of emissions of 

hydrogen sulfide as a by-product of rendering operations. 

EPA Response: As EPA discussed in the Notice of Intent to Lift the Stay (75 FR 8893, 8889, 

February 26, 2010), exposure consideration is not appropriate for chemicals that have moderately 

high to high chronic human health toxicity or high environmental toxicity. Hydrogen sulfide 

meets both of these criteria, therefore exposure (or the potential for exposure) is not a factor in 

the listing decision. 

Regarding EPCRA section 313(d)(2)(A), hydrogen sulfide is not listed under that criteria, 

but rather the criteria of EPCRA sections 313(d)(2)(B) and (C).
23

Comment:

Hydrogen sulfide is a naturally occurring gas associated with the anaerobic bacterial decay of 

organic matter. Roughly 90% of the total hydrogen sulfide in the atmosphere comes from natural 

sources such as volcanoes, oceans, stagnant waters like those found in swamps and bogs, and 

manure. About 100-324 million tons of hydrogen sulfide are annually emitted from these 

sources (ATSDR, 2006). Although difficult to quantify and highly variable, a typical rendering 

plant might emit roughly 400 pounds (not tons) of hydrogen sulfide per year. Hydrogen sulfide 

degrades rapidly in the environment, with an effective life-time of 2.3 days or less, based on a 

yearly average (ATSDR, 2006) so emissions are not likely to accumulate in the environment. 

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. Hydrogen sulfide releases in the 

rendering facility workplace environment tend to be fugitive in nature, inconsistent in 

concentration, and irregularly present. 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. 

Hydrogen 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. 

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 measureable or reliably quantifiable 

concentration. Through our years of studying potential hydrogen sulfide emissions in rendering 

operations, we know that it is difficult to quantify and report the low levels of emissions that may 

occur at our facilities. Therefore, we suggest that the addition of hydrogen sulfide to TRI listing 

by EPA must, at a minimum, allow for no TRI requirements for de minimums sources such as 

facilities in the rendering supply and processing chain.

EPA Response: It is well known that hydrogen sulfide is a byproduct of the rendering process 

(1). EPA has published emission factors for at least one stage of the rendering process (2). The 

commenter believes that reporting would be difficult for hydrogen sulfide, yet they provide an 

estimate of 400 pounds of releases per year, thus it appears that these facilities could make at 

least a reasonable estimate of releases as required under EPCRA section 313. EPA notes that 

rendering plants must already report their release of ammonia, another gas with variations in 

production and release. Regarding whether or not “emissions from a typical rendering plant 

likely result in air concentrations off-site that would be several orders of magnitude below 

concentrations that are potentially hazardous to human health and the environment,” unless the 

release data is made available the local communities and governments will not be able to confirm 

this conclusion. EPCRA section 313 contains no provisions for de minimis sources other than 

the fact that facilities must exceed the reporting thresholds (25,000 pounds for manufacture and 

processing and 10,000 pounds for otherwise use). It appears that rendering plants do not use 

hydrogen sulfide, thus they would have to manufacture or process 25,000 pounds before they 

would have to file a report. 
24

1. Emission Factor Documentation for AP-42 Section 9.5.3 Meat Rendering Plants Final Report. 

prepared by Midwest Research Institute (MRI) for the Office of Air Quality

Planning and Standards (OAQPS), U. S. Environmental Protection Agency (EPA), under EPA 

Contract No. 68-D2-0159. September 1995.

2. AP 42, Fifth Edition, January 1995. Compilation of Air Pollutant Emission Factors, Volume I: 

Stationary Point and Area Sources. Chapter 9: Food and Agricultural Industries section 9.5.3 

Meat Rendering Plants. Office of Air Quality Planning and Standards (OAQPS), Office of Air 

and Radiation, U. S. Environmental Protection Agency (EPA).

Comment:

If not for rendering in tithe U.S., 54 billion pounds of biological materials would be land filled, 

burned, buried, or inappropriately dumped with potentially huge uncontrolled amounts of carbon 

dioxide, methane, nitrogen nutrient, and other compounds ending up inn our air and water. From 

one landfill abalone, it is estimated that 16 tons of hydrogen sulfide is released into the air 

annually (ATSDRR, 2006), which is far more ((by several orders of magnitude) than the 

anticipated release from a typical rendering facility. When rendered, these products are dried, 

stabilized, and recycled for animal feed and energy. Many rendering companies also recycle 

used cooking oil from the restaurant and fast food industry to make befoul. Renderers are 

dedicated to improving the environment and have been doing so for many years. The rendering 

industry business model, in fact, is an important and valuable recycling industry that efficiently 

reduces environmental impacts that these biological materials might otherwise cause. 

The NRAA and the rendering industry are fully supportive of scientifically defensible and 

reasonable efforts to protect our nation’s environment. The NRA estimates that many millions 

of dollars are spent annually by the rendering industry on pollution control efforts. However, 

broad and overly protective efforts increase regulatory burdens and drive up costs that hinder our 

industry’s efforts to be economically sustainable and ultimately are counterproductive for our 

industry and the environment. We implore EPA to work with the rendering industry to 

accomplish worthy environmental goals that do not needlessly impose additional restrictions on 

rendering plant operations when there are practices currently in place that effectively protect 

worker safety, and human health and the environment. Moreover, additional restrictions on plant 

operations can force rendering plants out of business that will result in lost jobs, and a potentially 

worse environmental outcome if biological materials are not recycled via rendering but,, rather, 

are land-filled, burned, buried or inappropriately dumped. 

We appreciate this opportunity to provide comments on this proposed rule,, and EPA’s 

consideration of our recommendations. 

Senior Vice President, Scientific 

Services 
25

National Renderers Association 

Reference: 

Agency for Toxic Substances and Disease Registry (ATSDR)), 2006. Toxicological Profile for 

Hydrogen Sulfide. UU. S. Department of Health and Human Services. Public Health Service. 

July. 

EPA Response: EPA does not believe that the cost of filing one additional report under EPCRA 

section 313 would force a rendering plant out of business. EPCRA section 313 imposes no 

restrictions on the operation of a rendering plant; the only requirement is to file an annual report 

using reasonable estimates of releases and waste management quantities, as many of these 

facilities already file. EPA does not believe that providing the public with information on the 

releases and wastes management quantities of a highly toxic chemical such as hydrogen sulfide 

would be a broad or overly protective regulatory requirement.
26

Commenter: Hydrogen Sulfide Consortium [EPA-HQ-TRI-2009-0844-0087]

Comment:

I. EPA CANNOT PROPERLY LIMIT COMMENTS TO WHETHER OR NOT EPA 

SHOULD LIFT ITS ADMINISTRATIVE STAY OF EPCRA SECTION 313 

REPORTING REQUIREMENTS

In its proposal to lift the current stay of reporting requirements under EPCRA Section 

313 for H2S, EPA asserts: 

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 reporting requirements for hydrogen sulfide 

should be lifted.12

This characterization of the nature of the EPA proposal and of the scope of the opportunity for 

comment that EPA must provide is not supportable as a matter of fact or law. EPA has a legal 

obligation to reconsider its original listing determination, and to make a new determination that 

one or more of the statutory criteria in EPCRA Section 313(d)(2)13 have been satisfied before it 

may consider lifting the current stay. This obligation exists because this is what EPCRA requires 

as a matter of law, and EPA properly acknowledged it would do this when it adopted the 

administrative stay that it is now “announcing its intention” to lift. EPA has also acknowledged 

discrepancies between the rationale it provided when it first proposed a rule to list H2S and the 

rationale it provided when it adopted a final rule listing H2S. EPA stated that it would clarify its 

policy concerning use of exposure analysis to support listing under EPCRA Section 313(d)(2) 

and then adopted its current policy subsequent to the administrative stay. It must now afford an 

opportunity for comment on the manner in which it has applied that policy. 

EPA Response:

Commenters’ overarching argument is that “EPA cannot properly limit comments to 

whether or not EPA should lift its administrative stay of EPCRA section 313 reporting 

requirements,” but rather must revisit the original listing decision accomplished by final rule in 

1993. In support of this argument, commenters assert that: 1) EPA stated, when it issued the 

administrative stay in 1994, that it would revisit the original listing decision; 2) EPA cited 

chronic respiratory effects as one of the bases for listing under EPCRA section 313(d)(2)(B) in 

the proposed rule, but chronic neurotoxic effects as a basis under that same provision in the final 

rule; 3) EPA adopted its current policy regarding exposure analyses subsequent to the 1993 

listing of hydrogen sulfide; and 4) EPA “must make a new listing determination before it may lift 

[the stay].” For the reasons stated below, EPA disagrees with commenters that EPA must revisit 

the original listing decision in the context of EPA’s consideration of lifting the administrative 

stay of the EPCRA reporting requirements for hydrogen sulfide.

As described in detail below, EPCRA section 313(d)(2) states that EPA may add a 
27

chemical to the list if “there is sufficient evidence to establish any one” (emphasis added) of the 

listing criteria specified in section 313(d)(2). Therefore, to add a chemical, EPA must 

demonstrate that at least one criterion is met, but need not determine whether any other criterion 

is met.

EPA proposed to add hydrogen sulfide to the EPCRA section 313 list of toxic chemicals 

on September 8, 1992 (57 FR 41020) based on a determination that there was sufficient evidence 

establishing both chronic human health effects per EPCRA section 313(d)(2)(B) (specifically, 

chronic respiratory effects) and environmental effects per EPCRA section 313(d)(2)(C) 

(specifically, acute aquatic toxicity). On December 1, 1993, EPA promulgated a final rule 

adding hydrogen sulfide to the EPCRA section 313 list of toxic chemicals (58 FR 63500) 

(effective January 1, 1994). In the final rule, the listing decision was based on a determination 

that there was sufficient evidence establishing environmental effects per EPCRA section 

313(d)(2)(C) (specifically, the same acute aquatic toxicity as identified in the proposed rule) and 

chronic human health effects per EPCRA section 313(d)(2)(B). In the final rule, however, the 

chronic human health effects finding was based on chronic neurotoxic effects, instead of chronic 

respiratory effects as stated in the proposed rule.

After the final rule was issued adding hydrogen sulfide to the EPCRA section 313 list, 

and notwithstanding the fact that the Agency cited the same acute aquatic toxicity as an 

“environmental effects” basis for the listing under EPCRA section 313(d)(2)(C) in both the 

proposed rule and the final rule, some members of the regulated community expressed a concern 

that the Agency cited chronic respiratory effects as a “chronic human health effects” basis under 

EPCRA section 313(d)(2)(B) in the proposed rule, but chronic neurotoxic effects as a “chronic 

human health effects” basis under that same provision in the final rule. In addition, after 

issuance of the final rule, some members of the regulated community expressed concern that 

EPA’s decision not to include an exposure analysis in deciding to list hydrogen sulfide on the 

basis of chronic human health effects was inconsistent with past Agency practice. As a result of 

these concerns, some commenters threatened to bring legal action challenging the final rule. 

In response to the post-promulgation comments and concerns raised by some in the 

regulated community, and notwithstanding the fact that the listing decision was appropriate 

based on the acute aquatic toxicity finding alone under EPCRA section 313(d)(2)(C), EPA issued 

an administrative stay of the EPCRA section 313 reporting requirements for hydrogen sulfide on 

August 22, 1994 (59 FR 43048) in order to review those post-promulgation comments and 

concerns. 

The stay issued on August 22, 1994 made clear that: “The effect of this stay is to defer 

reporting on [hydrogen sulfide] while the Agency reviews new data and information made 

available subsequent to the promulgation of the final rule.” 59 FR 43048 (Aug. 22, 1994) 

(emphasis added). As a result, while the subsequent stay deferred reporting requirements, the 

stay did not remove hydrogen sulfide from the EPCRA section 313 list or alter that final listing 

determination, which remained in effect as of January 1, 1994. The listing determination was 

never administratively or judicially challenged.

On February 26, 2010, EPA issued a notice announcing its “Intent to consider lifting [the 
28

hydrogen sulfide] administrative stay; opportunity for public comment.” 75 FR 8889 

(hereinafter Intent to Lift the Stay). That document stated: “The purpose of this document is to 

provide the public with the opportunity to comment on EPA’s review of the currently available 

data on the human health and environmental effects of hydrogen sulfide ... and EPA’s belief that 

the Administrative Stay should be lifted based on that data.... In addition, this document 

addresses the concerns raised regarding use of exposure analyses.” Id. at 8891. The Intent to 

Lift the Stay notice clearly explained: “By this current action, EPA is not revisiting the original 

listing decision, which was accomplished by final rule on December 1, 1993. Rather, EPA is 

merely presenting its rationale for why the Administrative Stay of the reporting requirements for 

hydrogen sulfide should be lifted.” Id. at 8889 (emphasis added). 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.

Comment:

A. When EPA Entered the Administrative Stay, EPA Expressly Stated That It 

Would Either Propose to Delete Hydrogen Sulfide from the EPCRA Section 313 

List or Reaffirm Its Original Listing Decision 

At the time EPA adopted the present administrative stay for H2S and methyl mercaptan, 

EPA explicitly stated that it would issue “a forthcoming Federal Register notice” in which it 

would “seek public comment on whether the Agency should propose to delete one or both of 

these chemicals from the EPCRA section 313 list of toxic chemicals.”14 EPA has never issued 

any notice until now that could be construed as seeking further comment on its listing 

determination for H2S. The original notice announcing the administrative stay clearly stated: 

After evaluating the information and public comments the Agency 

will either propose to delete one or both of the chemicals or will 

reaffirm its original findings and dissolve this Administrative 

Stay.15 

Elsewhere in the notice, EPA elaborated as follows: 

The Agency feels that it is important and appropriate to 

administratively stay the effectiveness of the listing of these two 

chemicals while giving the public an opportunity to comment on 

these issues and the additional information, as well as to comment 

on whether the Agency’s initial determination that both hydrogen 

sulfide and methyl mercaptan satisfy the section 313(d) criteria for 

addition to the list of toxic chemicals.16 

By the way it has characterized its current proposal to lift the long-pending stay, EPA has 

contravened what it expressly represented to the regulated community and the interested public 

in 1994. 

12 75 Fed. Reg. at 8889. 
29

13 42 U.S.C. § 11023(d)(2). 

14 59 Fed. Reg. at 43048

15 Id.

16 Id.

EPA Response:

Commenters first argue that EPA cannot now limit comment to whether or not to lift the 

stay because the Agency stated, when it issued the administrative stay in 1994, that it intended, at 

some point in the future, to “seek comment on the Agency’s initial determination for [hydrogen 

sulfide].” 59 FR at 43049. Specifically, the administrative stay stated:

[T]he Agency will be issuing a forthcoming Federal Register notice which will 

seek comment on the Agency’s initial determination for [hydrogen sulfide], ... 

procedural issues concerning the initial final rule, and generally, comments (and 

any supporting data) on whether the Agency should either propose to delete 

[hydrogen sulfide] or affirm its initial determination and dissolve today’s 

Administrative Stay.

Id.

Hydrogen sulfide was listed under section 313 of EPCRA by final rule on December 1, 

1993. The stay did not remove hydrogen sulfide from the EPCRA section 313 list or alter that 

final listing determination, which was never administratively or judicially challenged. The 1993 

listing decision was appropriate base on the acute aquatic toxicity finding alone under EPCRA 

section 313(d)(2)(C), which was included in both the proposed and final rules and never 

questioned. Therefore, EPA does not believe it is necessary or appropriate to revisit the 1993 

final listing of hydrogen sulfide in order to lift the stay of reporting requirements. 

Further, the Agency believes that its action in taking comment on its intent to lift the stay 

is substantially in accord with the course of action it described in issuing the stay in 1994. In the 

Intent to Lift the Stay notice, the Agency discussed and invited comment on the data underlying 

its consideration of the matter and EPA’s application of its policy regarding exposure assessment 

to the listing decision. As described in the Intent to Lift the Stay notice, EPA’s planned course 

of action arises out of EPA’s review of the currently available data, which clearly demonstrate 

both chronic health effects in humans (upper respiratory tract toxicity and neurotoxicity) and 

significant adverse effects in aquatic organisms (acute, chronic, and early life stage). Further, 

EPA’s consideration of these effects is fully consistent with its policy on exposure assessment. 

Based on these findings, EPA believes that there is no basis for continuing the administrative 

stay of the reporting requirements for hydrogen sulfide, and that the administrative stay should 

therefore be lifted. 

Moreover, these findings also demonstrate that there is no basis to consider delisting 

hydrogen sulfide. EPCRA section 313(d)(3) states that to remove a chemical from the list, EPA 

must determine that “there is not sufficient evidence to establish any” of the Section 313(d)(2) 
30

criteria (emphasis added). Therefore, to remove a chemical, EPA must demonstrate that none of 

the criteria are met. As EPA’s review of the currently available data in the context of its 

consideration of lifting the Administrative Stay demonstrates, EPA cannot show that none of the 

criteria are met. Indeed, the Agency believes that the only course available is to dissolve the 

stay, which it is doing through notice-and-comment, and which is substantially in accord with at 

least one of the alternative courses anticipated in 1994.

Finally, to the extent that the commenters are suggesting that EPA is legally prohibited 

from now limiting comment to the issue of whether or not to lift the Administrative Stay based 

on the statements in the preamble the Agency made (excerpted above) when issuing the 

Administrative Stay, EPA respectfully notes that these preamble statements do not create such a 

legal obligation. See, e.g., Natural Resources Defence Council v. EPA, 559 F.3d 561, 564–65 

(D.C. Cir. 2009).

Comment:

B. In the Administrative Stay, EPA Acknowledged Significant Discrepancies 

between the Rationale When EPA First Proposed to List H2S and the 

Rationale Provided for the Actual Listing of H2S 

When it first proposed to add H2S to the EPCRA Section 313 list, EPA based its proposal 

on a number of respiratory effects that it characterized as “chronic effects”17 of the sort that 

would warrant a listing decision under EPCRA Section 313(d)(2)(B).18 EPCRA Section 

313(d)(2)(B) provides that EPA may add a chemical to the original statutory list if there is 

sufficient evidence to establish that: 

(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.

19 

In the final rule listing H2S, EPA agreed with commenters that the respiratory effects it 

had cited in the proposed rule were “likely due to irritation of [an] acute nature.”20 Although 

EPA acknowledges that the first listing criterion for acute effects in EPCRA Section 

313(d)(2)(A)21 requires consideration of actual exposure, EPA did not conduct any exposure 

analysis for H2S for this final rule. Rather, EPA based its final decision listing H2S on 

neurotoxic effects that had been observed in occupational settings following chronic exposure to 

high levels of H2S.

22 Thus, the public was deprived of any meaningful opportunity to comment 

on EPA’s revised rationale for listing H2S. 
31

In its decision to adopt an administrative stay of reporting requirements for H2S, EPA 

acknowledged this discrepancy. EPA stated that “the Agency cited chronic neurotoxic effects in 

the final rule and chronic respiratory effects in the NPRM.”23 Although EPA did not expressly 

admit the obvious procedural deficiency that infected its original listing decision for H2S, it did 

state: 

[T]he Agency believes that this Administrative Stay is appropriate and in the 

interests of justice, given the allegations of procedural and substantive 

deficiencies surrounding the Agency’s listing of these two chemicals.24 

EPA also alluded to statements by two affected trade associations that “unless administrative 

action is taken to resolve the issues outlined in today’s document, a prompt legal challenge will 

be brought.”25 Under any reasonable interpretation of all of these statements when EPA adopted 

the administrative stay, EPA cannot now lift the stay without affirming its previous listing 

decision for H2S and EPA cannot affirm the listing without providing full notice and comment 

concerning its current rationale for a determination that the listing criteria have been satisfied.

17 EPA, Chemicals; Toxic Chemical Release Reporting; Community Right-to-Know; 

Proposed Significant New Use Rule, Proposed Rule, 57 Fed. Reg. 41020, 41027-28 

(Sept. 8, 1992). 

18 42 U.S.C. § 11023(d)(2)(B). 

19 Id. 

20 58 Fed. Reg. at 63509. 

21 42 U.S.C. § 11023(d)(2)(A).

22 58 Fed. Reg. at 63509.

23 59 Fed. Reg. at 43049.

24 Id. at 43050.

25 Id. 

EPA Response:

Second, Commenters argue that EPA cannot now limit comment to whether or not to lift 

the stay because EPA cited chronic respiratory effects as one of the bases for listing under 

EPCRA section 313(d)(2)(B) in the proposed rule, but chronic neurotoxic effects as a basis under 

that same provision in the final rule.

EPCRA section 313(d) authorizes EPA to add or delete chemicals from the list and sets 

forth criteria for these actions. The EPCRA section 313(d)(2) criteria are:

(A) The chemical is known to cause or can reasonably be anticipated to 

cause significant adverse acute human health effects at concentration levels that 

are reasonably likely to exist beyond facility site boundaries as a result of 

continuous, or frequently recurring, releases.

(B) The chemical is known to cause or can reasonably be anticipated to 

cause in humans-

(i) Cancer or teratogenic effects, or
32

(ii) Serious or irreversible-

(I) Reproductive dysfunctions,

(II) Neurological disorders,

(III) Heritable genetic mutations, or

(IV) Other chronic health effects.

(C) The chemical is known to cause or can be reasonably anticipated to 

cause, because of

(i) Its toxicity,

(ii) Its toxicity and persistence in the environment, or

(iii) Its toxicity and tendency to bioaccumulate in the environment, 

a significant adverse effect on the environment of sufficient seriousness, in the 

judgment of the Administrator, to warrant reporting under this section.

EPA often refers to the section 313(d)(2)(A) criterion as the “acute human health effects 

criterion;” the section 313(d)(2)(B) criterion as the “chronic human health effects criterion;” and 

the section 313(d)(2)(C) criterion as the “environmental effects criterion.”

While it is true that the Agency cited chronic respiratory effects as a “chronic human 

health effects” basis under EPCRA section 313(d)(2)(B) in the proposed rule, but chronic 

neurotoxic effects as a “chronic human health effects” basis under that same provision in the 

final rule, it bears emphasizing once again that the Agency also separately cited the same acute 

aquatic toxicity as an “environmental effects” basis for the listing under EPCRA section 

313(d)(2)(C) in both the proposed and final rules. As a result, and in light of the fact that 

EPCRA section 313(d)(2) expressly allows EPA to add a chemical to the list if “there is 

sufficient evidence to establish any one” of the listing criteria (emphasis added), the 1993 listing 

decision was appropriate based on the acute aquatic toxicity finding alone under EPCRA section 

313(d)(2)(C). That basis for the listing was never questioned and was and continues to be 

supported by the data relied upon by EPA in determining that the stay should be lifted. Any 

procedural error that may have occurred regarding the section 313(d)(2)(B) “chronic human 

health effects” finding was harmless in light of the unchallenged section 313(d)(2)(C) 

“environmental effects” finding presented in both the proposed and final rules. This analysis 

also played directly into EPA’s decision to proceed in the manner it has, as opposed to rigidly 

following its stated intentions in 1994.

EPA is currently lifting the stay of hydrogen sulfide reporting requirements – a substance 

that has been and remains listed under EPCRA since promulgation of the final rule on December 

1, 1993 – based on EPA’s review of the currently available data, which clearly demonstrate both 

chronic health effects in humans (upper respiratory tract toxicity and neurotoxicity) and 

significant adverse effects in aquatic organisms (acute, chronic, and early life stage). EPA is not 

revisiting the original listing determination, and comments on the original listing decision are 

beyond the scope of this action. 

Comment:

C. In the Administrative Stay, EPA Stated That It Would Clarify Its Position 
33

Concerning Use of Exposure Analysis in EPCRA Section 313 Listings, 

and EPA Subsequently Adopted a New Policy Concerning This Issue 

In its decision to adopt an administrative stay of reporting requirements for H2S, EPA 

also referred to comments by regulated parties that EPA did not correctly utilize exposure 

analysis when it applied the statutory listing criteria to H2S. Although EPA disputed comments 

that the use of exposure analysis for H2S “was inconsistent with past Agency practice,” EPA 

acknowledged that it would be helpful to clarify this question. EPA stated: 

The Agency believes that a consistent approach to the EPCRA 

section 313 listing process is both necessary and important and 

that, given the charges of inconsistency with respect to exposure 

analysis, the public deserves an opportunity to be presented with 

further clarification of the Agency’s position on this critical 

issue.26 

EPA then promised to include a “more complete discussion” of the EPA policy on use of 

exposure analysis in applying the listing criteria in EPCRA Section 313(d)(2) in a forthcoming 

Federal Register notice concerning H2S and methyl mercaptan.

EPA subsequently provided a statement of its policy concerning use of exposure analysis. 

This occurred, however, as part of another unrelated rulemaking adding chemicals to the EPCRA 

Section list of toxic chemicals.27 Until the issuance of the current notice, EPA never applied this 

policy statement in determining whether H2S satisfies any of the statutory listing criteria. Thus, 

EPA cannot now deprive interested parties of an opportunity for notice and comment on the

manner in which its policy on exposure analysis has been applied in making a new listing 

determination for H2S.28 Further, because EPA is applying its subsequently adopted policy 

concerning exposure analysis to H2S for the first time, EPA cannot properly apply that policy 

without affording a full opportunity for notice and comment rulemaking.29 

26 Id. 

27 EPA, Addition of Certain Chemicals; Toxic Chemical Release Reporting; Community 

Right-to-Know, Final Rule, 59 Fed. Reg. 61432, 61433, 61440-42 (Nov. 30, 1994). 

28 See 5 U.S.C. §§ 553(b), 553(c); see also McLouth Steel Prods. Corp. v. Thomas, 838 

F.2d 1317, 1323 (D.C. Cir. 1988). 

29 See McLouth supra, 838 F.2d at 1323; see also Community Nutrition Inst. v. Young, 818 

F.2d 943, 948-49 (D.C. Cir. 1987). 

EPA Response:

Third, Commenters argue that EPA cannot now limit comment to whether or not to lift 

the stay because EPA adopted its current policy regarding exposure analysis subsequent to the 

1993 listing of hydrogen sulfide.
34

EPA did not “adopt[] a new policy” on its use of exposure analysis for listing chemicals 

under EPCRA section 313 subsequent to the listing of hydrogen sulfide in 1993. Instead, the 

Agency’s then-existing position on the use of exposure analyses in listing decisions under 

EPCRA section 313 was presented in a proposed rule in the Federal Register of January 12, 1994 

(59 FR 1788). That proposed rule provided the public with the opportunity to comment on the 

Agency’s then-existing interpretation of the statutory listing criteria as it relates to the use of 

exposure considerations. After considering the comments received, EPA published in the 

Federal Register of November 30, 1994 (59 FR 61432) a “chemical expansion” final rule, 

including a statement clarifying its interpretation of the statutory requirements regarding how 

exposure is considered in listing decisions. Subsequent to that final rule, EPA’s interpretation of 

the statutory listing criteria as it relates to the consideration of exposure was upheld in National 

Oilseed Processors Ass’n. v. Browner, 924 F. Supp. 1193 (D.D.C. 1996), aff’d in part & 

remanded in part, Troy Corp. v. Browner, 120 F.3d 277 (D.C. Cir. 1997).

As stated in the chemical expansion final rule:

Through this rulemaking, EPA is clarifying its position regarding the use 

of hazard, exposure, and risk in listing decisions under EPCRA section 313. EPA 

will consider exposure factors when making determinations under section 

313(d)(2)(A) (acute human toxicity). In addition, EPA has discretion to consider

exposure factors where appropriate for determinations under sections

313(d)(2)(B) (chronic human toxicity) and (C) (environmental toxicity), and that 

there is a broader range of circumstances in which exposure will be considered 

under section 313(d)(2)(C) than under (B).

EPA has reviewed its past listing decisions in light of this clarification, 

and believes that its prior listing determinations have been consistent in the 

consideration of exposure in 31 of the 32 listing/delisting determinations previous

to this action....

59 FR 61442 (Nov. 30, 1994) (emphasis added). In Troy Corp. v. Browner, the D.C. Circuit 

agreed with EPA, finding:

Were the EPA to abandon a long-held exposure policy and take a new direction 

we would, as urged, require a thorough explanation of its reasons for doing so. 

Yet, the EPA’s pronouncement in its preamble of its exposure policy is not a 

change in course. With one exception, the EPA has consistently stated, as it does 

in this rulemaking, that it will consider exposure under subsection (B) only when 

the chemical was of “low to moderately low” toxicity. ... [T]he agency has long 

maintained that it would consider exposure under subheading (B) only for low 

toxicity chemicals. The inorganic fluorides petition was denied over ten years 

ago. Since that time, the agency has made several dozen listing and delisting 

decisions under EPCRA. The inorganic fluorides case was the only instance in 

which the agency articulated a policy contrary to the one explicated in this 

rulemaking. Under these circumstances we cannot say that the agency has 

departed from prior practice in a way that requires more explanation than was 

provided.
35

Troy Corp. v. Browner, 120 F.3d at 287 (emphasis added) (citation omitted).

Thus, EPA did not subsequently adopt a new exposure policy as Commenters suggest. 

Rather, the Agency simply clarified the existing exposure policy. Further, the 31 of 32 previous 

cases, noted by the court in Troy Corp., in which the Agency had been consistent with this 

exposure policy included the listing of hydrogen sulfide. Therefore, EPA had applied this same 

exposure policy to the listing of hydrogen sulfide, and need not, as Commenters suggest, provide 

a new notice and opportunity to comment on the use of exposure analyses in listing hydrogen 

sulfide under section 313 of EPCRA. 

As EPA explained in the Intent to Lift the Stay:

EPA has determined that hydrogen sulfide can reasonably be anticipated to cause serious 

or irreversible chronic human health effects at relatively low doses and thus is considered 

to have moderately high to high chronic toxicity. EPA does not believe that it is 

appropriate to consider exposure for chemicals that are moderately high to highly toxic 

based on a hazard assessment when determining if a chemical can be listed for chronic 

effects pursuant to EPCRA section 313(d)(2)(B) (see 59 FR 61432, 61433, 61440-

61442). Hydrogen sulfide has also been determined to cause ecotoxicity at relatively low 

concentrations, and thus is considered to have high ecotoxicity. EPA believes that 

chemicals that induce death or serious adverse effects in aquatic organisms at relatively 

low concentrations (i.e., they have high ecotoxicity) have the potential to cause 

significant changes in the population of fish and other aquatic organisms, and can 

therefore reasonably be anticipated to cause a significant adverse effect on the 

environment of sufficient seriousness to warrant reporting. EPA does not believe that it 

is required to consider exposure for chemicals that have high ecotoxicity based on a 

hazard assessment when determining if a chemical can be listed for effects pursuant to 

EPCRA section 313(d)(2)(C) (see 59 FR 61432, 61433, 61440-61442).

75 FR 8889, 8893 (Feb. 26, 2010).

 

Comment:

D. EPA Must Make a New Determination Applying the Statutory Listing 

Criteria Based on Current Scientific Information and Reaffirm the Current 

Listing Before It May Lawfully Lift the Administrative Stay of Reporting 

Requirements 

EPA conducted a rulemaking to adopt the original listing decision for H2S. EPA later 

acknowledged that it had not provided for proper comment on the actual substantive predicate 

for its listing determination in that rulemaking and clearly stated it would do so. EPA also stated 

that it would clarify its policy on use of exposure analysis for listing decisions under the criteria 

in EPCRA Section 313(d)(2) before taking final action, and EPA subsequently adopted a new 

policy on the use of such analyses. 
36

Given these factors, it is unreasonable and unlawful for EPA to decline now to revisit the 

original listing. Simply because EPA used an adjudicatory order to suspend enforcement of 

reporting requirements, pending review of its original listing decision does not change its 

obligation to provide full notice and comment on the basis for a new listing determination before 

it may lift that order. EPA must make a new listing determination applying the statutory listing 

criteria and utilizing current scientific data, and then take comment on whether one or more of 

the applicable criteria have been satisfied. Only after completing these steps may EPA proceed 

either to delete H2S from the list or to reaffirm its original listing determination and to lift the 

administrative stay. 

While an agency may make changes in a proposed rule on the basis of public comments 

received on the proposal, at least where the changes are a “logical outgrowth” of the proposal 

and the comments, a like justification does not apply here.30 The 1994 H2S listing decision 

rested on such shaky grounds that, as noted, EPA immediately stayed the effect of the listing. 

EPA’s inability to respond satisfactorily to comments raised nearly two decades ago lies at the 

core of the problem, and it cannot properly decline to revisit the listing decision or to provide an 

opportunity for public comment. This is all the more necessary in that lifting the stay would 

reverse completely the status quo from the regulatory standpoint.31

The Consortium recognizes that, notwithstanding EPA’s stated intent not to revisit the 

1993 final rule listing H2S, EPA has provided an explanation of why it believes that two of the 

statutory listing criteria are satisfied, which is based on some of the currently available scientific 

data. EPA has also purported to apply its current policy concerning use of exposure analyses in 

listing determinations. Nevertheless, as we will show below, the explanation given by EPA is 

insufficient to support a listing decision because EPA has not considered all of the best available 

scientific data, and because EPA has applied its stated policy on use of exposure analyses in an 

arbitrary manner. 

30 See Sprint Corp. v. FCC, 315 F.3d 369, 374-75 (D.C. Cir. 2003), distinguishing the 

situations in City of Stoughton v. EPA, 858 F.2d 747, 751 (D.C. Cir. 1988) and American 

Mining Congress v. EPA, 907 F.2d 1179, 1182 (D.C. Cir. 1990). Significantly, too, in 

American Mining Congress, while the reviewing court upheld EPA’s reinstatement of a 

withdrawn listing rule for certain hazardous wastes, on the ground that EPA had provided 

two opportunities for comment on the original rule, the court also rejected the 

reinstatement as to other wastes in the absence of rational connection between the data 

and those listing decisions). 

31 See Sprint Corp. v. FCC, supra, 315 F.3d at 374 (opportunity for comment necessary 

when an agency “changes the rules of the game”). 
37

EPA Response:

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.

Comment:

II. EPA MAY NOT IMPLEMENT ITS POLICY CONCERNING USE OF EXPOSURE 

ANALYSIS IN MAKING LISTING DECISIONS UNDER EPCRA SECTION 313 IN 

AN ARBITRARY MANNER 

Comment: A. EPA Has Not Identified the Specific Criteria It Utilizes in 

Determining Whether a Substance Causes Chronic Human Health 

Effects at Relatively Low Doses or Ecotoxicity at Relatively Low 

Concentrations 

In its proposal to lift the administrative stay for H2S, EPA states that it is applying the 

interpretation of the statutory listing criteria and the policy concerning use of exposure analyses 

adopted by EPA in its November 30, 1994, final rule listing other substances.32 In that rule, EPA 

stated: 

The Agency believes that exposure considerations are appropriate in 

making determinations (1) under section 313(d)(2)(A), (2) under section 

313(d)(2)(B) for chemicals that exhibit low to moderately low toxicity 

based on a hazard assessment (i.e., those chemicals for which the value of 

listing on the EPCRA section 313 list on hazard alone is marginal), and (3) 

under section 313(d)(2)(C) for chemicals that are low or moderately 

ecotoxic.33 

EPA also notes that the interpretation of the statutory listing criteria that underlies this 1994 

policy statement was sustained during subsequent judicial review.34

Although EPA asserts in its proposal to lift the stay that it has applied the 1994 policy on 

use of exposure analyses to H2S,35the Consortium has been unable to identify or locate in the 

docket for this matter any objective criteria that EPA uses in making a determination of whether 

a particular candidate substance that may cause “serious or irreversible chronic health effects” 

has “low to moderately low toxicity.” Similarly, the Consortium has not been able to find any 

explanation of the criteria that EPA uses in deciding whether a particular candidate substance has 

“low to moderately low ecotoxicity.” 

Even if it is assumed that EPA has the discretion to select a policy concerning the 

circumstances in which it will use an exposure analysis as part of a listing decision under 

EPCRA Section 313(d)(2), that does not mean that EPA has unfettered discretion to apply that 
38

policy in an arbitrary manner.36 If EPA is to have a rational policy that can be applied in a fair 

and equitable manner, the scientists conducting a hazard assessment for a candidate substance 

under EPCRA Section 313(d)(2) should not be permitted to make qualitative judgments 

concerning potential toxicity in the absence of any objective criteria or guidance concerning 

what these terms mean.37 

32 See 59 Fed. Reg. at 61440-42. 

33 59 Fed. Reg. at 61441. 

34 See Troy Corp. v. Browner, 120 F.3d 277, 285-87 (D.C. Cir. 1997), reh’g denied on 

other grounds, 129 F.3d 1290 (D.C. Cir. 1997). 

35 75 Fed. Reg. at 8893. 

36 Because the stay has been in place for the life of the H2S listing, the change effected by 

lifting the stay and thus reinstating the listing calls for a greater, and not a lesser, level of 

scientific support; agency action is subject to heightened scrutiny when it reflects a change in a 

long-standing policy. See Michigan Public Power Agency v. FERC, 405 F.3d 8, 12 (D.C. Cir. 

2005). 

37 It is axiomatic that an agency must provide a reasoned basis for its actions, Motor Vehicle 

Mfrs. Ass’n v. State Farm Mutual Ins. Co., 463 U.S. 29, 43 (1983), and also that it must examine 

the relevant data and articulate a satisfactory basis for its action, including a “rational connection 

between the facts found and the choice made,” Citizens to Preserve Overton Park, Inc. v. Volpe, 

401 U.S. 402, 416 (1971); Northwest Coalition for Alternatives to Pesticides v. EPA, 544 F.3d 

1043, 1052 (9th Cir. 2008). 

EPA Response: Commenters state that even if EPA has discretion to select a policy concerning 

the circumstances in which exposure analysis will be part of the EPCRA section 313(d)(2) listing 

decision, it does not mean the EPA has unfettered discretion to apply that policy in an arbitrary 

manner. Commenters state that if EPA is to have a rational policy that can be applied in a fair 

and equitable manner, the scientists conducting a hazard assessment under EPCRA section 

313(d)(2) should not be permitted to make qualitative judgments concerning potential toxicity in 

the absence of objective criteria or guidance concerning what these terms mean. However, as 

discussed below, this is precisely the question at issue in National Oilseed Processors Ass’n. v. 

Browner, 924 F. Supp. 1193 (D.D.C. 1996), aff’d in part & remanded in part, Troy Corp. v. 

Browner, 120 F.3d 277 (D.C. Cir. 1997), where those Courts held that EPA’s exposure analysis 

policy, including the determination of when a toxic chemical has “moderately high to high 

toxicity” based on adverse effects at “low” or “moderate” dose levels and thus does not require 

an exposure analysis in order to be listed, was not arbitrary or capricious.

EPA has identified the criteria that it uses in making a determination of whether a 

substance that may cause “serious or irreversible chronic health effects” has “low to moderately 

low toxicity,” and has not applied its policy on the use of exposure analysis in EPCRA section 

313 listing determinations in an arbitrary manner. To the contrary, in the preamble to the 1994 
39

chemical expansion final rule, EPA explained that two types of chemicals are considered to 

exhibit moderately high to high toxicity:

● Where a review of the scientific data provides a high level of confidence that the 

chemical causes an adverse effect at relatively low dose levels, and

● Where a review of the scientific data indicates that the chemical will cause various 

adverse effects at moderate dose levels.

[59 FR 61432, 61433 (Nov. 30, 1994)]. 

Thus, EPA has in fact articulated criteria for its determination whether or not exposure 

considerations will be taken into account in its chemical listing decisions.

More specifically, EPA has provided guidance concerning how it evaluates chemicals to 

determine whether they meet the EPCRA section 313 listing criteria, including information on 

the factors EPA considers in determining whether a chemical is sufficiently toxic that exposure 

need not be considered in the listing decision. The specific criteria EPA uses to determine

whether a chemical has moderately high or high toxicity, and thus does not have low to 

moderately low toxicity, were explained in detail in the 1994 chemical expansion rule:

3. Hazard evaluation. After completing the screening phase, EPA conducted a thorough 

hazard assessment for each of the addition candidates that resulted from the above 

analyses and determined based on the weight-of-the evidence if there was sufficient 

evidence to establish that the candidate chemical met the statutory criteria for addition to 

EPCRA section 313. To make this determination, EPA senior scientists reviewed readily 

available toxicity information on each chemical for each of the following effect areas: 

acute human health effects; cancer; other chronic human effects; and environmental 

effects. In addition, EPA reviewed, where appropriate, information on the environmental

fate of the chemical.

The hazard assessment was conducted in accordance with relevant EPA

guidelines for each adverse human health or environmental effect (e.g., the appropriate 

guidelines for hazard evaluation of chemical carcinogens and for the type of evidence 

required to substantiate a determination of carcinogenicity are the Assessment Guidelines 

for Carcinogen Risk (Ref. 4)). During this assessment the number, severity, and 

significance of the effects induced by the chemical, the dose level causing the effect, and 

the quality and quantity of the available data, including the nature of the data (e.g., 

human epidemiological, laboratory animal, field or workplace studies) and confidence 

level in the existing data base, were all considered. Where a careful review of the 

scientific data for a particular chemical results in a high level of confidence that the 

chemical causes an adverse effect at relatively low dose levels, EPA believes that this

evidence is sufficient for listing the chemical under section 313. EPA also believes that 

where a review of the scientific data indicates that the chemical will cause various 

adverse effects at moderate dose levels, the total weight-of-the-evidence indicates that 

there is sufficient evidence for listing the chemical under EPCRA section 313. EPA 
40

believes that both types of chemicals described above exhibit moderately high to high 

toxicity based on a hazard assessment.

 EPA also conducted an analysis of exposure for each chemical or chemical

category proposed for listing under EPCRA section 313(d)(2)(A) (i.e., based on adverse 

acute human health effects), and, where appropriate, under section 313(d)(2)(C) (i.e., 

based on adverse ecological effects). For chemicals listed under EPCRA section 

313(d)(2)(A), this analysis included estimated concentrations of the chemical at or 

beyond the facility site 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 based on a hazard assessment (see Unit IV.B. for a discussion of the use of

exposure). As discussed more thoroughly in Unit IV.B. of this preamble, EPA does not 

believe that it is appropriate to factor exposure into the listing decisions for the chemicals 

being listed pursuant to section 313(d)(2)(B) in this rulemaking.

 Following a review and analysis of the information available about each chemical 

in this final rule (including information provided through public comment) by senior 

Agency scientists, the Agency concludes that for each of the chemicals listed one or more 

of the EPCRA section 313 listing criteria are met. Moreover, the adverse effects 

associated with each of the chemicals being listed today are serious and significant. In 

some cases the effects are extreme, such as cancer or death. In others, the effects are 

serious and lasting, including, for example, impairment of a fetus' or an offspring's 

physical development, neurological effects inhibiting motor abilities or mental processes 

or impairing the ability to reproduce, or the sustainability of a fragile ecosystem such as

an estuary. For a number of chemicals in the final rule, there is more than one adverse 

effect.

 It is important to understand that although an adverse effect is known or can be 

reasonably anticipated to be caused by a chemical on the section 313 list, a release of a 

chemical into a community does not necessarily mean that the effect will occur. 

Exposure and dose are also important factors in determining whether an adverse effect 

occurs and how serious the manifestation will be. The listing of a chemical on the 

section 313 list does not mean that a particular community will experience these adverse 

effects. Instead the purpose for listing a chemical is to ensure that the public gets 

information about releases of such chemicals. Thus, EPA believes that for chemicals that 

typically do not affect solely one or two species but rather affect changes across a whole 

ecosystem and for which there is well-documented evidence supporting the adverse 

effects, that their addition to the EPCRA section 313 list is warranted even though the

severity of the adverse effects that they induce will be dependent upon site-specific 

characteristics. Once EPA makes release data available through TRI, the community 

may then make its own determination on the importance of these releases (and their 

potential adverse effects).

[59 FR at 61433, 11/30/1994 (emphasis added)] 
41

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

Through this rulemaking, EPA is clarifying its position regarding the use of hazard, 

exposure, and risk in listing decisions under EPCRA section 313. EPA will consider 

exposure factors when making determinations under section 313(d)(2)(A) (acute human 

toxicity). In addition, EPA has discretion to consider exposure factors where appropriate 

for determinations under sections 313(d)(2)(B) (chronic human toxicity) and (C) 

(environmental toxicity), and that there is a broader range of circumstances in which 

exposure will be considered under section 313(d)(2)(C) than under (B). 

EPA has reviewed its past listing decisions in light of this clarification, and believes that 

its prior listing determinations have been consistent in the consideration of exposure in 31 

of the 32 listing/delisting determinations previous to this action, including a number of 

deletions of low toxicity chemicals that Congress placed on the initial EPCRA section 

313 list. EPA is currently reviewing the one exception, inorganic fluorides, to determine 

if additional action is warranted. EPA will continue to evaluate petitions according to 

this clarification and will delete chemicals that do not meet the statutory criteria. 

[59 FR at 61442, 11/30/1994]

EPA’s exposure analysis policy, as set forth in the chemical expansion Final Rule, was 

judicially challenged in National Oilseed Producers Ass’n v. Browner, 924 F. Supp. 1193 

(D.D.C. 1996). There, the plaintiffs presented precisely the same argument that the Hydrogen 

Sulfide Consortium now raises. In National Oilseed, the court stated that “Plaintiffs ... claim 

that EPA has not adequately explained when it will consider exposure under Section 

313(d)(2)(B).” National Oilseed, 924 F. Supp. at 1203. The court squarely rejected that 

argument, holding:

The Agency argues generally that, in the exercise of its discretion, it has 

elected to consider exposure only in limited circumstances. Specifically, when 

EPA’s hazard assessment shows that a chemical exhibits only low or moderately 

low toxicity, EPA will consider the potential for exposure in making a listing 

decision. Conversely, where EPA’s hazard assessment reveals that a chemical’s 

toxicity is high or moderately high, EPA does not consider exposure, and will list 

the chemical based solely on its toxic effect.

...

Moreover, EPA asserts that it explained adequately on the record that it 

chose to not consider exposure in this rulemaking because all of the chemicals 

proposed for listing under Section 313(d)(2)(B) were of “high to moderatelyhigh” toxicity and therefore consideration of exposure was not appropriate.

After consideration of the extensive arguments on both sides of this issue, 

the Court concludes that the Agency did not act arbitrarily and capriciously in 

declining to consider exposure in the listing decisions for this rulemaking. ... 

While a more clearly and fully articulated policy would be preferable, the Court 

cannot conclude that EPA was unreasonable in exercising its discretion by 

continuing to exclude consideration of exposure when chemicals are of high to 
42

moderately-high toxicity.

...

What is significant is that EPA stated what its policy for consideration of 

exposure would be, and then described its application to the chemicals considered 

in this rulemaking.

 Because EPA’s decision to not consider exposure in this rulemaking was 

consistent with its policy of using exposure data only in particular circumstances, 

i.e., where chemicals are of low toxicity, the Court concludes that the Agency was 

not arbitrary and capricious.

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

On appeal to the U.S. Court of Appeals for the D.C. Circuit, the plaintiffs again raised 

this same argument. There, the court stated: “...[Plaintiffs] argue that the EPA abused its 

discretion and acted arbitrarily and capriciously by failing to establish criteria for the 

consideration of exposure....” Troy Corp. v. Browner, 120 F.3d 277, 282 (D.C. Cir. 1997). On 

this point, the D.C. Circuit rejected the plaintiffs’ argument and affirmed the judgment of the 

D.C. District Court in National Oilseed. Troy Corp., 120 F.3d at 293.

Just as EPA did in the 1994 chemical expansion rule and other previous listing decisions, 

upheld by the Courts in National Oilseed and Troy Corp. – including application of the Agency’s 

exposure analysis policy in conducting such hazard assessments – EPA conducted a hazard 

assessment of the human health and ecological effects of hydrogen sulfide, upon which the 

determinations that hydrogen sulfide has moderately high to high human toxicity were based.

Based on the data from the hazard assessment, as presented in the Federal Register notice and 

supporting documents, EPA determined that hydrogen sulfide has moderately high to high

toxicity to humans and is highly toxic to aquatic organisms. EPA discussed these determinations 

in detail in the notice of Intent to Lift the Stay in the Federal Register [75 FR 8889, 2/26/2010]. 

Human health toxicity was discussed in detail beginning on page 8891, with references, and 

ecological effects were discussed in detail beginning on page 8893, with references. 

In the section of the Federal Register document that discussed the rationale for lifting the 

stay, EPA provided the following summary of the hazard data:

EPA’s technical evaluation of hydrogen sulfide shows that it can reasonably be 

anticipated to cause chronic health effects in humans. The chronic health effects have 

been observed in laboratory animals at concentrations as low as 28 mg/m3 (20 ppm) and 

41.7 mg/m3 (30 ppm). In addition, EPA’s technical evaluation of hydrogen sulfide also 

shows that it can reasonably be anticipated to cause, because of its toxicity, significant 

adverse effects in aquatic organisms. Examples of hydrogen sulfide’s ecological toxicity 

include acute toxicity (96-hour LC50) values for freshwater fish that ranged from 0.0149 

mg/L (fathead minnow) to 0.0448 mg/L (bluegill), indicating high aquatic toxicity. 

Examples of hydrogen sulfide’s chronic ecological toxicity include freshwater fish values 

that ranged from a 6-week LOEC (growth rate) of 0.0005 mg/L in a tropical fish (Mystus 

nemurus) to a 430-day LOEC (final weight) of 0.009 mg/L for goldfish, also indicating 

high aquatic toxicity.
43

[75 FR 8893, 2/26/2010]

As the language above clearly shows, EPA did identify the information and the rationale 

for why hydrogen sulfide was determined to have moderately high to high human toxicity and 

high ecotoxicity.

Comment:

B. Although EPA Asserts That It Has Determined H2S Can Cause Chronic 

Human Health Effects at Relatively Low Levels and Ecotoxicity at 

Relatively Low Concentrations, EPA Has Not Given Its Rationale for This 

Determination 

The problem with EPA’s purported determination that H2S meets two of the statutory 

listing criteria is not confined to the lack of any discernable objective criteria or guidance that 

EPA scientists are supposed to apply. EPA has not provided any rationale for the determinations 

upon which it bases its conclusion that no exposure assessment is needed as it must. 

EPA has provided a description of its hazard assessment for chronic human health 

effects, including respiratory effects and neurotoxic effects,38which is based on the IRIS review 

for H2S that EPA did in 2003.39 EPA has also provided a description of its hazard assessment for 

potential ecological toxicity of H2S.40 EPA asserts that it has also made the requisite 

determinations concerning the relative magnitude of H2S toxicity for chronic human health 

effects and for ecological effects. EPA states: 

EPA has determined that hydrogen sulfide can reasonably be anticipated to cause 

serious or irreversible chronic human health effects at relatively low doses and 

thus is considered to have moderately high to high chronic toxicity. 

... 

Hydrogen sulfide has also been determined to cause ecotoxicity at 

relatively low concentrations, and thus is considered to have high 

ecotoxicity.41 

The problem with these statements by EPA is that they are wholly conclusory. The 

docket compiled by EPA does not appear to contain any explanation of the relation between the 

hazard assessments prepared by EPA scientists and these determinations. Not only has EPA 

given no objective criteria against which these determinations can be tested, but it also has given 

no explanation of why EPA scientists believe that chronic human health effects may be caused 

by H2S “at relatively low doses” or that ecotoxicity may result from H2S at “relatively low 

concentrations.” As such, EPA has failed to meet the fundamental requirement that it must 

“support its decisions with the necessary scientific findings.”42 

These critical omissions from the record are of significant interest to the Consortium, 

because its members believe that there is no real possibility that any of these effects will be 

caused by H2S releases of the sort that would be reportable under EPCRA Section 313. From the 
44

perspective of Consortium, the H2S levels that have been characterized by EPA as “relatively 

low” are actually very high. 

For example, EPA summarizes the information on chronic health effects by stating: 

These effects occur in a clear dose concentration manner with the 

lowest levels of hydrogen sulfide exposure associated with these 

effects ranging from 20 to 30 ppm (28 mg/m3to 41.7 mg/m3).

43 

These effect levels are 2,000 to 3,000 times greater than the odor detection threshold for H2S of 

10 ppb. Although routine emissions from sources that would be subject to reporting 

requirements under the EPA proposal may result in ambient H2S concentrations that exceed the 

odor detection threshold, these concentrations will always be far below the lowest levels for 

chronic effects in animals cited in the hazard assessment by EPA. 

The 1990 CAA Amendments included a provision requiring EPA to study H2S emissions 

associated with the extraction of oil and natural gas.44 In the resultant report, EPA determined 

that emissions from these activities resulted in measured levels that were consistently in 

compliance with the state standards.45Based on this analysis, EPA concluded that “there appears 

to be no evidence that a significant threat to public health or the environment exists from routine 

H2S emissions from sour oil and gas extraction.”

46

 A subsequent study performed in 1999 by the 

Public Health Service (PHS) and EPA in one city near H2S sources found that peak H2S levels 

were generally below and only occasionally exceeded the upper detection limit of 90 ppb.47 

As part of a 2005 rulemaking to establish a new 83 ppb (24-hour average) ambient 

standard for H2S, the State of North Carolina conducted a survey of state standards and 

concluded that 32 states have established ambient air standards for H2S. These standards have 

averaging times that range from instantaneous to annual. The highest one-hour average and the 

highest 24-hour average H2S levels permitted by any state standard are 200 ppb.48Thus, even the 

highest permitted H2S ambient concentrations are 100 to 150 times less than the lowest levels for 

chronic effects in animals cited in the hazard assessment by EPA. The highest permitted 

concentration is also 25 times less than the 5 ppm No Observed Effect Level (NOEL) for 

neurobehavioral and neurosensory effects established in a recent clinical study involving 

exposure of human volunteers conducted by Fiedler, et al.

49

This 2008 study was not included in 

the information considered by EPA in the 2003 IRIS review, and is discussed in more detail 

below. 

EPA bases its evaluation that H2S is ecotoxic at “relatively low concentrations” 

exclusively on potential effects on aquatic life, noting that toxicity values for aquatic species 

include “numerous values that are well below 1 milligram per liter (mg/L).”50 While the levels 

cited by EPA may seem “relatively low” in the abstract, they are actually quite high when 

viewed in the context of data that clearly establish that H2S will be rapidly oxidized to less toxic 

chemical forms when released to surface waters.51The EPA Water Quality Criteria Gold Book 

makes a similar observation: 

The fact that H2S is oxidized in well-aerated water by natural 
45

biological systems to sulfates or is biologically oxidized to 

elemental sulfur has caused investigators to minimize the toxic 

effects of H2S on fish and other aquatic life.52 

EPA has not explained the basis for its conclusory statements that the H2S levels that may be 

associated with chronic health effects and ecotoxicity are “relatively low.” These unsupported 

determinations fail to satisfy either the legal standard imposed under EPCRA or the general legal 

requirements established by the Administrative Procedure Act (APA).53 

38 75 Fed. Reg. at 8892-93. 

39 IRIS Assessment (June 2003). 

40 75 Fed. Reg. at 8893. 

41 Id. 

42 National Gypsum Co. v. EPA, 968 F.2d 40, 41, 47 (D.C. Cir. 1992) (NPL listing 

remanded; EPA must provide “scientific findings” and “reasoned explanation”); see Tex Tin 

Corp. v. EPA, 935 F.2d 1321, 1324 (D.C. Cir. 1991) (NPL listing remanded; reviewing court 

“cannot defer to agency expertise that was never explained”).

43 75 Fed. Reg. at 8893. 

44 CAA § 112(n)(5), 42 U.S.C. § 7412(n)(5). 

45 EPA, Office of Air Quality Planning and Standards, Report to Congress on 

Hydrogen Sulfide Air Emissions Associated With the Extraction of Oil and 

Natural Gas, EPA-453/R-93-045 (Oct. 1993), at III-19 to III-31 (OAQPS Study). 

46 OAQPS Study at V-1. 

47 PHS, Agency for Toxic Substances and Disease Registry (ATSDR), Toxicological 

Profile for Hydrogen Sulfide (July 2006), at 125. 

48 North Carolina Division of Air Quality, State Survey of Ambient Air Standards, 

available at http://daq.state.nc.us/toxics/studies/H2S/H2S_Survey.pdf. 

49 Fiedler N., Kipen H., Ohman-Strickland P., Zhang J., Weisel C., Laumbach R., KellyMcNeil K., Olejeme K., and Lioy P. (2008). Sensory and Cognitive Effects of Acute Exposure 

to Hydrogen Sulfide. Env. Health Persp. 116(1):78-85. 

50 75 Fed. Reg. at 8893. 

51 Millero, F.J., Hubinger, Fernandez and Garnett (1987). Oxidation of H2S in Seawater as a 

Function of Temperature, pH and Ionic Strength. Env. Sci. Tech. 21:439-443; Obrien, D.J. and 

Birkner, F.B. (1977). Kinetics of Oxygenation of Reduced Sulfur Species in Aqueous Solutions. 

Env. Sci. Tech. 11:1114-1120. 

52 EPA, Office of Water Regulations and Standards, Quality Criteria for Water, EPA 440/5-
46

86-001 (May 1, 1986) (EPA Gold Book), at 268. 

53 See, e.g., United Mine Workers v. Dep’t of Labor, 358 F.3d 40, 45 (D.C. Cir. 2004) 

(federal agency cannot justify decision-making by conclusory assertions); Portland Cement 

Ass’n v. Ruckelshaus, 486 F.2d 375, 393 (D.C. Cir. 1973), cert. denied, 417 U.S. 921 (1974) 

(“not consonant with the purpose of a rule-making proceeding to promulgate rules on the basis 

of inadequate data, or on data that, critical degree, is known only to the agency”). 

EPA Response: As discussed in the previous response, EPA has provided guidance on how it 

determines whether a chemical has moderately high to high human toxicity and high ecotoxicity. 

In the notice of Intent to Lift the Stay, EPA provided a detailed hazard assessment of both the 

human health effects and the ecological effects of hydrogen sulfide. This included both the 

effects caused by hydrogen sulfide and the doses/concentrations that caused those effects. This 

information was discussed in the Federal Register [75 FR 8889, 2/26/2010], and the details were 

contained in the hazard assessments and other references cited by EPA. Specifically, at 75 FR 

8889, 8891-8893 (Feb. 26, 2010), EPA’s lengthy and detailed technical review of hydrogen 

sulfide (Part IV. of the Federal Register notice, entitled “What is EPA’s Technical Review of 

Hydrogen Sulfide?”), including references, can be found (and need not be reiterated here). EPA 

then concluded, based on the hazard assessment:

EPA has determined that hydrogen sulfide can reasonably be anticipated to cause serious 

or irreversible chronic human health effects at relatively low doses and thus is considered 

to have moderately high to high chronic toxicity.... Hydrogen sulfide has also been 

determined to cause ecotoxicity at relatively low concentrations, and thus is considered to 

have high ecotoxicity. EPA believes that chemicals that induce death or serious adverse 

effects in aquatic organisms at relatively low concentrations (i.e., they have high 

ecotoxicity) have the potential to cause significant changes in the population of fish and 

other aquatic organisms, and can therefore reasonably be anticipated to cause a 

significant adverse effect on the environment of sufficient seriousness to warrant 

reporting. 

[75 FR 8893, 2/26/2010]

In the section of the Federal Register document that discussed the rationale for lifting the 

stay, EPA provided the following summary of the hazard data:

EPA’s technical evaluation of hydrogen sulfide shows that it can reasonably be 

anticipated to cause chronic health effects in humans. The chronic health effects have 

been observed in laboratory animals at concentrations as low as 28 mg/m3 (20 ppm) and 

41.7 mg/m3 (30 ppm). In addition, EPA’s technical evaluation of hydrogen sulfide also 

shows that it can reasonably be anticipated to cause, because of its toxicity, significant 

adverse effects in aquatic organisms. Examples of hydrogen sulfide’s ecological toxicity 

include acute toxicity (96-hour LC50) values for freshwater fish that ranged from 0.0149 

mg/L (fathead minnow) to 0.0448 mg/L (bluegill), indicating high aquatic toxicity. 

Examples of hydrogen sulfide’s chronic ecological toxicity include freshwater fish values 

that ranged from a 6-week LOEC (growth rate) of 0.0005 mg/L in a tropical fish (Mystus 
47

nemurus) to a 430-day LOEC (final weight) of 0.009 mg/L for goldfish, also indicating 

high aquatic toxicity.

[75 FR 8893, 2/26/2010]

The above determinations are based on the human health effects and ecological effects 

caused by hydrogen sulfide and the doses/concentrations that caused those effects. EPA clearly 

stated why the hazard assessment supports a finding of moderately high to high human toxicity 

and high ecotoxicity. Therefore, EPA has clearly stated how the hazard assessment data supports 

a conclusion that hydrogen sulfide has moderately high to high human toxicity and high 

ecological toxicity.

Regarding the information that the commenter provided on previous exposure 

assessments, air standards, etc., none of that information is relevant to a determination that 

hydrogen sulfide has moderately high to high human toxicity or high ecological toxicity. The 

toxicity of a chemical is separate from whether there are exposures from facility releases of that 

chemical or not. In addition, the information provided by the commenter does not demonstrate

that releases of hydrogen sulfide could not reach a level of concern from all the types of facilities 

that report under EPCRA section 313. EPA notes that the examples of the very low air standards 

for hydrogen sulfide of 83 – 200 parts per billion support EPA’s determination that hydrogen 

sulfide is highly toxic. 

The commenter’s statement that the cited toxic effects of hydrogen sulfide are 2,000 to 

3,000 times greater than the odor detection threshold for H2S of 10 ppb is not a basis for 

discounting the toxic effects of hydrogen sulfide. As EPA has stated:

“Recent reviews of the health hazards associated with H2S exposure and subsequent 

treatment include Milby and Baselt (1999a) and Guidotti (1996). Earlier reviews of the 

health effects were provided by Glass (1990), Reiffenstein et al. (1992), and Mehlman 

(1994). Exposure to H2S has been reported to be an important cause of morbidity and 

mortality in the workplace (Snyder et al., 1995) and olfactory dysfunction (Hirsch and 

Zavala, 1999). These reviews indicate that the typical “rotten-egg odor” of H2S is an 

inadequate warning indicator of exposure since levels in the range of 100-200 ppm (140-

280 mg/m3) can lead to loss of smell followed by olfactory paralysis (Reiffenstein et al., 

1992).” 

[IRIS, 2003, page 10]

In addition, simply because someone can smell hydrogen sulfide does not mean they will 

automatically remove themselves from that exposure. Individuals that are frequently exposed to 

hydrogen sulfide may become less sensitive to the smell and, as indicated in the IRIS 

assessment, it is possible to have loss of smell from hydrogen sulfide exposure.

Commenters further state that:

EPA bases its evaluation that H2S is ecotoxic at “relatively low concentrations” 
48

exclusively on potential effects on aquatic life, noting that toxicity values for aquatic 

species include “numerous values that are well below 1 milligram per liter (mg/L).” 

While the levels cited by EPA may seem “relatively low” in the abstract, they are actually 

quite high when viewed in the context of data that clearly establish that H2S will be 

rapidly oxidized to less toxic chemical forms when released to surface waters. The EPA 

Water Quality Criteria Gold Book makes a similar observation: 

The fact that H2S is oxidized in well-aerated water by natural biological 

systems to sulfates or is biologically oxidized to elemental sulfur has 

caused investigators to minimize the toxic effects of H2S on fish and other 

aquatic life.

(Footnotes omitted)

The quote from the water quality criteria document that “[t]he fact that H2S is oxidized in 

well-aerated water by natural biological systems to sulfates or is biologically oxidized to 

elemental sulfur has caused investigators to minimize the toxic effects of H2S on fish and other 

aquatic life” is from the introductory paragraph of the water quality criteria for hydrogen sulfide. 

This statement simply explains what has caused some investigators in the past to minimize the 

toxic effects of hydrogen sulfide. However, in the rationale section, the document goes on to 

discuss the toxicity of hydrogen sulfide to aquatic life in detail and does not dismiss the potential 

impacts hydrogen sulfide may have on aquatic life. In fact, the document presents the rationale 

for setting a water quality criterion of just 2 ug/L undissociated hydrogen sulfide for fish and 

other aquatic life in both fresh and marine water. Concerning oxidation, the EPA Gold Book 

states:

The degree of hazard exhibited by sulfide to aquatic animal life is dependent on the 

temperature, pH, and dissolved oxygen. At lower pH values a greater proportion is in the 

form of the toxic undissociated H2S. In winter when the pH is neutral or below or when 

dissolved oxygen levels are low but not lethal to fish, the hazard from sulfide is 

exacerbated. 

[EPA Gold Book, May 1, 1986, page 268]

The criteria document also states that:

Many past data on the toxicity of hydrogen sulfide to fish and other aquatic life have been 

based on extremely short exposure periods. Consequently, these early data have 

indicated that concentrations between 0.3 and 0.4 mg/L permit fish to survive (Van Horn 

1958, Boon and Follie 1967, Theede et al., 1969). Recent long-term data, both in field 

situations and under controlled laboratory conditions, demonstrate hydrogen sulfide 

toxicity at lower concentrations.

[EPA Gold Book, May 1, 1986, page 268]

and concludes that:
49

“Available data indicate that water containing concentrations of 2.0 ug/L undissociated 

H2S would not be hazardous to most fish and other aquatic wildlife, but concentrations in 

excess of 2.0 ug/L would constitute a long-term hazard.” 

[EPA Gold Book, May 1, 1986, page 270 (emphasis added)]

The conclusion that a concentration of hydrogen sulfide in excess of just 2.0 ug/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 commenter concerning oxidation of hydrogen 

sulfide in seawater and aqueous solutions (i.e., Millero, F.J., Hubinger, Fernandez and Garnett 

(1987). Oxidation of H2S in Seawater as a Function of Temperature, pH and Ionic Strength. Env. 

Sci. Tech. 21:439-443; Obrien, D.J. and Birkner, F.B. (1977). Kinetics of Oxygenation of 

Reduced Sulfur Species in Aqueous Solutions. Env. Sci. Tech. 11:1114-1120.), the Millero 

reference was cited in EPA’s hazard assessment (page 8) and the Obrien reference was cited in 

the Millero reference (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, 2009). 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 conditions does not mean that it is not highly toxic. As 

was cited above, the EPA Gold Book stated:

The degree of hazard exhibited by sulfide to aquatic animal life is dependent on the 

temperature, pH, and dissolved oxygen. At lower pH values a greater proportion is in the 

form of the toxic undissociated H2S. In winter when the pH is neutral or below or when 

dissolved oxygen levels are low but not lethal to fish, the hazard from sulfide is 

exacerbated. 

[EPA Gold Book, May 1, 1986, page 268]

If hydrogen sulfide were rapidly oxidized to harmless chemicals under all environmental 

conditions, then that would have an impact on EPA’s assessment, but that is certainly not the 

case. How much damage a particular release of hydrogen sulfide will cause can depend on a 

number of factors including the amount of the release, whether the release is continuous or 

infrequent, the pH of the water, the temperature of the water, the type of water (fresh or 

seawater), the time of year, velocity of the body of water, etc. These factors would be 

considered in site specific exposure and risk assessments. While hydrogen sulfide may be 

oxidized under certain environmental conditions, there are many common environmental 

conditions under which oxidation will not be significant and thus will not lessen the impact of a 

release of hydrogen sulfide. As the aquatic toxicity data shows, hydrogen sulfide is toxic to 

many different aquatic species and at several stages of life with some toxicity values at or below 
50

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 sea water. Considering how low the 48 and 96 hour LC50

values are for hydrogen sulfide, hydrogen sulfide toxicity is still a concern even under favorable 

oxidation conditions. The potential oxidation of hydrogen sulfide does not lessen the inherent 

toxicity of hydrogen sulfide. 

EPA notes that, other than the single quote from the water quality criteria document and 

two references concerning oxidation of hydrogen sulfide in water, the commenters have not 

questioned or tried to refute in any way the aquatic toxicity information provided in EPA’s 

hazard assessment. The summary table of the aquatic toxicity values presented in the hazard 

assessment provided over 90 toxicity values from more than a dozen sources. The commenters 

did not provide any specific comments on why those data should not be considered sufficient to 

support EPA’s conclusions.

With regard to the commenter’s statements concerning criteria or guidance for 

determining whether a chemical has moderately high to high human toxicity or high ecological 

toxicity, it appears that the commenters may have been looking for some type of numerical 

cutoffs. The comments regarding criteria or guidance for determining whether a chemical has 

moderately high to high human toxicity or high ecological toxicity, have been addressed in 

EPA’s other responses to the commenters. With regard to possible numerical cutoffs, EPA does 

not agree that numerical cutoffs should be or need to be established in order to determine 

whether a chemical has moderately high to high human toxicity or high ecological toxicity. As 

EPA explained in the chemical expansion rule in 1994:

The hazard assessment was conducted in accordance with relevant EPA guidelines for 

each adverse human health or environmental effect (e.g., the appropriate guidelines for 

hazard evaluation of chemical carcinogens and for the type of evidence required to 

substantiate a determination of carcinogenicity are the Assessment Guidelines for 

Carcinogen Risk (Ref. 4)). During this assessment the number, severity, and significance 

of the effects induced by the chemical, the dose level causing the effect, and the quality 

and quantity of the available data, including the nature of the data (e.g., human 

epidemiological, laboratory animal, field or workplace studies) and confidence level in 

the existing data base, were all considered. Where a careful review of the scientific data 

for a particular chemical results in a high level of confidence that the chemical causes an 

adverse effect at relatively low dose levels, EPA believes that this evidence is sufficient 

for listing the chemical under section 313. EPA also believes that where a review of the 

scientific data indicates that the chemical will cause various adverse effects at moderate 

dose levels, the total weight-of-the-evidence indicates that there is sufficient evidence for 

listing the chemical under EPCRA section 313. EPA believes that both types of 

chemicals described above exhibit moderately high to high toxicity based on a hazard

assessment. 

[59 FR 61433, 11/30/1994].

EPA provided a hazard assessment that presented the information used to support the 

finding that hydrogen sulfide has moderately high to high human toxicity and high ecotoxicity. 
51

As in the 1994 rulemaking, and subsequent rulemakings, the data presented in the hazard 

assessments addressed issues such as the number, severity, and significance of the effects 

induced by the chemical, the dose level causing the effect, and the quality and quantity of the 

available data, including the nature of the data (e.g., human epidemiological, laboratory animal, 

field or workplace studies) and confidence level in the existing data base. All commenters had 

the opportunity to comment on whether these data support EPA’s determinations regarding the 

toxicity of hydrogen sulfide in response to EPA’s notice of Intent to Lift the Stay of the reporting 

requirements for hydrogen sulfide. Establishing a numerical cutoff would limit EPA’s ability to 

consider other factors that might increase or decrease the concern for the toxicity of a chemical. 

For example, if one chemical causes one serious effect at 100 mg/kg/day and another chemical 

causes multiple serious effects across multiple organ systems but at 300 mg/kg/day it would not 

make sense to discount the latter if there were some arbitrary numerical cutoff of 200 mg/kg/day. 

EPA does not believe that would be the correct way to evaluate chemicals for listing. Rather,

EPA considers all of the toxicity data, including the doses/concentrations causing the toxic 

effects, in making determinations about the toxicity of a chemical. EPA provided this 

information in the hazard assessment for hydrogen sulfide and provided its rationale for lifting 

the stay based on this information.

While EPA has not set numerical cutoffs, a quick review of the chemicals included in the 

1994 chemical expansion rule (59 FR 61432, 11/30/1994), the Persistent, Bioaccumulative, and 

Toxic (PBT) rule (64 FR 693, 1/5/1999), and other actions shows that the doses and 

concentrations that cause adverse effects for hydrogen sulfide are well within those of chemicals 

that EPA has previously determined to have moderately high to high human toxicity and high 

ecotoxicity. In fact, with regard to ecotoxicity, some of the levels at which hydrogen sulfide

causes toxicity are among the lowest that EPA has evaluated. Even if EPA were to establish a 

numerical cutoffs, based on EPA’s previous listing determinations the levels at which hydrogen 

sulfide causes toxicity would be well below any such numerical cutoffs.

With regard to the phrase “relatively low doses,” this simply refers to doses that are low 

relative to the body burden they impose. Dose levels are most often measured as (or converted 

into) the units milligrams per kilogram per day (mg/kg/day) where kilogram refers to each 

kilogram of body weight. As noted above, EPA has explained that in determining whether a 

chemical has moderately high to high chronic toxicity the dose levels causing the effects along 

with the number and severity of the adverse effects are considered (59 FR 61433, 1/30/1994). 

While EPA has not set a numerical cutoff for a relatively low dose, it has provided numerous 

examples of the dose levels that EPA considers to be relatively low as well as dose levels that 

EPA considers to be relatively high. The 1994 chemical expansion rule alone contains over 200 

examples of relatively low doses (59 FR 1788, 1/12/1994). Doses in that rule that were 

considered relatively low were generally at or below 100 mg/kg/day. EPA has also identified, 

through numerous actions, dose levels that are considered to be high or relatively high. Such 

dose levels are typically at or above 500 mg/kg/day, with most examples being in excess of 

1,000 mg/kg/day or more (see for example: 59 FR 49888, 9/30/1994; 60 FR 46076, 9/5/1995, 

and 64 FR 8769, 2/23/1999). Even in the rulemaking that added hydrogen sulfide to the TRI list, 

EPA identified doses of 600 and 1,000 mg/kg/day as “relatively high doses” (57 FR 41020, 

9/8/1992). These “relatively high doses” were cited by EPA in the determinations that bchloronapthalene and isobutyl alcohol were not sufficiently toxic to be added to the EPCRA 
52

section 313 list (57 FR 41033, 9/8/1992). These dose levels are significantly higher than the less 

than 15 mg/kg/day doses (converted from 20 - 30 ppm) that EPA has cited as being relatively 

low for hydrogen sulfide. While EPA has not set a numerical cutoff for relatively low doses, the 

Agency has provided, through the listing and delisting of chemicals, substantial guidance for this 

terminology. 

As EPA has noted, low dose alone is not the only consideration in determining whether a 

chemical has moderately high to high toxicity and thus should be listed on hazard alone: 

Where a careful review of the scientific data for a particular chemical results in a high 

level of confidence that the chemical causes an adverse effect at relatively low dose 

levels, EPA believes that this evidence is sufficient for listing the chemical under section 

313. EPA also believes that where a review of the scientific data indicates that the 

chemical will cause various adverse effects at moderate dose levels, the total weight-ofthe-evidence indicates that there is sufficient evidence for listing the chemical under 

EPCRA section 313. EPA believes that both types of chemicals described above exhibit 

moderately high to high toxicity based on a hazard assessment. (59 FR 61433, 

1/30/1994).

An example of this concept is the listing of triphenyltin chloride. This chemical was cited by 

EPA as causing significant reproductive toxicity, including adverse effects on the testes, 

epididymis, sperm duct, prostate gland, seminal vesicle, Cowper's gland, and accessory glands, 

at an oral dose of 380 mg/kg over 19 days. While the dose level was more moderate, EPA 

determined that the severity and number of effects were sufficient for listing (59 FR 1843, 

1/12/1994). This is the kind of flexibility regarding dose levels that is required when making 

determinations about the toxicity of chemicals, and is consistent with the exposure policy EPA 

has established for EPCRA section 313 determinations.

Regarding the phrase “relatively low concentrations” used in the assessment of ecological 

toxicity, this is similar to the “relatively low dose” terminology in that it focuses on 

concentrations that result in low doses to the organisms. Data for aquatic organisms is the most 

commonly cited data and typically has the units of milligrams per liter (mg/L). As EPA has 

stated, exposure assessments are not used to list a chemical for ecological effects if it has high 

toxicity. Based on concentration, EPA has typically limited its consideration of highly toxic to 

those chemicals that cause acute effects at about 1 mg/L or less and chronic effects at 0.1 mg/L 

or less (see for example: 57 FR 41020, 9/8/1992 and 59 FR 1788, 1/12/1994). Since the 

statutory criteria of EPCRA section 313(d)(2)(C) also includes consideration of persistence and 

bioaccumulation, EPA has considered somewhat higher concentrations as highly toxic for 

chemicals with those characteristics (64 FR 696, 1/5/1999). As with chronic human health 

effects, EPA has not set a numerical cut off for relatively low concentrations, but has provided, 

through the listing and delisting of chemicals, substantial guidance for this terminology.

EPA notes that other programs within the Agency that have numerical cutoffs for aquatic 

organisms have set numerical cutoffs that are consistent with the kind of toxicity concentrations 

that EPA has identified has being highly toxic in EPCRA section 313 evaluations. For example, 

the Office of Pesticide Programs cites the following:
53

Ecotoxicity Categories for Terrestrial and Aquatic Organisms

Aquatic Organisms: Acute

Concentration (ppm) Toxicity Category

<0.1 very highly toxic

0.1 – 1 highly toxic

>1 – 10 moderately toxic

>10 – 100 slightly toxic

>100 practically nontoxic

(http://www.epa.gov/oppefed1/ecorisk_ders/toera_analysis_eco.htm#Ecotox).

Under the above numerical cutoffs, not only would hydrogen sulfide be considered highly toxic, 

but most of the available data would support a classification of very highly toxic.

Comment:

C. The Lack of Any Objective Rationale for EPA’s Determination That H2S 

Causes Health and Ecological Effects at Relatively Low Levels Suggests 

That EPA Has Made a Qualitative Judgment about the Magnitude of 

Potential Exposure without Preparing Any Supporting Exposure Analysis 

EPA has not provided any objective criteria that may have been used when it made its 

determinations that H2S can be anticipated to cause chronic human health effects and ecological 

toxicity at “relatively low levels,” and also has not provided any details concerning the specific 

methodology utilized by EPA to make these determinations. In the absence of such information, 

it is impossible to provide a more specific critique of the methodology that EPA used. EPA 

cannot properly make a new determination that H2S satisfies the statutory criteria for listing 

under EPCRA Section 313(d)(2) without disclosing this methodology and providing a proper 

opportunity for comment.54 

One possibility is that EPA scientists have simply made a qualitative judgment 

concerning the plausibility that H2S exposure might occur at the levels in question. Such a 

judgment would be intrinsically arbitrary when it is possible to do a proper and defensible 

exposure analysis.55 If such an analysis were performed, the Consortium is confident that it would 

show that levels approaching the effect levels for chronic human health effects and ecological 

toxicity identified by EPA will not be attained as a result of routine H2S emissions.

54 See American Farm Bureau Fed’n v. EPA, 559 F.3d 512, 523 (2009) (EPA’s choice of 

methodology must make sense); Puerto Rico Sun Oil Co. v. EPA, 8 F.3d 73, 77 (1st Cir. 1993) 

(an agency decision must be “rational -- technically speaking, it must not be ‘arbitrary and 

capricious’ . . . -- and that requirement exists even in technical areas of regulation”). 

55 See American Farm Bureau Fed’n v. EPA, supra, 559 F.3d at 520-22) (relation of EPA’s 

exposure data to regulatory choices made must be relevant and subject to rational explanation). 

EPA Response: As discussed in a previous response to this commenter, EPA has provided the 
54

information it used to determine that hydrogen sulfide has moderately high to high human 

toxicity and high ecotoxicity and has explained the methodology by which EPA makes such 

determinations. Therefore, EPA disagrees with the commenter’s statement that EPA did not 

provide an objective rationale for its determinations.

Commenter asserts that:

“One possibility is that EPA scientists have simply made a qualitative judgment concerning the 

plausibility that H2S exposure might occur at the levels in question. Such a judgment would be 

intrinsically arbitrary when it is possible to do a proper and defensible exposure analysis.”

There is nothing in the materials that EPA has provided that even suggests that EPA made a 

qualitative judgment about hydrogen sulfide exposure levels. The determination as to whether or 

not a chemical has moderately high to high human toxicity or high ecotoxicity is separate from 

any consideration of potential exposures. EPA did not consider or evaluate the potential 

exposures to hydrogen sulfide in making its finding that hydrogen sulfide has moderately high to 

high toxicity to humans and is highly toxic to aquatic organisms. The toxicity of a chemical is 

an intrinsic property of the chemical that is established by determining what exposure level (i.e., 

dose) causes adverse effects through appropriately conducted toxicological studies; it is not 

based on releases that occur at facilities. Consideration of the level of exposure from releases 

occurring at facilities is part of a risk assessment, not a hazard assessment. Unlike the intrinsic 

toxicity of a chemical, exposure levels can change depending on many factors such as release 

quantities, type of release, changes in weather 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 

section 313 list does not mean that a particular community will experience these adverse 

effects. Instead the purpose for listing a chemical is to ensure that the public gets 

information about releases of such chemicals. Thus, EPA believes that for chemicals that 

typically do not affect solely one or two species but rather affect changes across a whole 

ecosystem and for which there is well-documented evidence supporting the adverse 

effects, that their addition to the EPCRA section 313 list is warranted even though the 

severity of the adverse effects that they induce will be dependent upon site-specific 

characteristics. Once EPA makes release data available through TRI, the community 

may then make its own determination on the importance of these releases (and their 

potential adverse effects). 

[59 FR 61433, 11/30/1994]

In upholding EPA’s interpretation of EPCRA section 313 listing decisions as it relates to 

the use of exposure, the U.S. Court of Appeals for the District of Columbia Circuit itself

provided a very good example of the difference between the toxicity of a chemical and exposure 

to that chemical:
55

It is not the case that the congressional language mandating listing of a chemical that ‘is 

known to cause or can reasonably be anticipated to cause in humans’ the enumerated 

adverse effects unambiguously incorporates the likelihood of contact between humans 

and the chemical. A simple analogy quickly refutes NPG's argument that the language is 

unambiguous. Consider a herpetologist and a student contemplating a reptile imprisoned 

in a glass cage. The student asks, ‘Can that snake's bite reasonably be anticipated to 

cause death in humans?’ The scientist replies, ‘Yes.’ The scientist is not commenting on 

the likelihood of the serpent's escape, only the toxicity of its venom. Concededly, his 

answer could be taken to mean, ‘Yes, it is likely that this creature will escape, bite 

someone, and kill them.’ But that is certainly not the unambiguous purport of his words. 

Even so is the statutory language of Congress. It is conceivable that Congress may have 

contemplated release in its phrasing of the standard, but that is certainly not 

unambiguously the case.

[Troy Corp. v. Browner, 120 F.3d 277, 285 (D.C. Cir. 1997).]

The example of a venomous snake in a glass cage provides a perfect illustration of the 

difference between exposure and toxicity. Just as the containment of the venomous snake in a 

glass cage does not change the fact that the snake’s venom is highly toxic, lack of exposure does 

not lessen the intrinsic toxicity of a chemical. Lack of exposure addresses the issue of the level 

of risk, not the level of toxicity.

Comment:

III. THE HAZARD EVALUATION BY EPA DID NOT PROPERLY CONSIDER THE 

BEST AVAILABLE SCIENTIFIC EVIDENCE CONCERNING H2S TOXICITY AND 

EXPOSURE 

A. EPA Has Not Properly Considered Recent Clinical Data Concerning the 

Neurobehavioral Effects of H2S 

The hazard assessment for potential chronic human health effects conducted by EPA to 

support its determination under EPCRA Section 313(d)(2)(B) is based on the IRIS Assessment 

for H2S. Because the IRIS document was completed in 2003, it does not reflect some of the best 

available scientific information. EPA should base its current hazard assessment on all relevant 

current information.56 

As EPA has acknowledged, the nasal olfactory lesions that have been nominally 

characterized by EPA as chronic respiratory effects are likely to just be another manifestation of 

neurotoxicity, “such that consideration of one may be inclusive of the other.”57The conclusions 

in the EPA chronic toxicity hazard assessment concerning the levels at which H2S causes various 

types of neurotoxicity and nasal lesions are all based on animal studies, which EPA has deemed 

to be of likely relevance to potential effects in humans. Because one important clinical study of 

potential neurological effects of H2S exposure in humans was conducted subsequent to 

completion of the IRIS assessment, EPA has not considered it.
56

In Fiedler et al. (2008), 74 healthy male and female volunteers participated in a clinical 

study designed to evaluate neurobehavioral effects of 2-hour controlled chamber exposures to 

H2S. Neurobehavioral effects were evaluated using a battery of established tests immediately 

prior to, and immediately following, exposure to 0.05, 0.5, and 5.0 ppm H2S in separate sessions 

approximately one week apart. The sequence of exposures was randomly assigned to each 

subject. The investigators reported that no significant changes were found between pre- and postexposure performance, and that no dose-response was found in any of the neurobehavioral or 

neurosensory data sets. 

Although the exposures studied in the Fiedler et al. (2008) study did not constitute 

chronic exposure, this study is highly relevant in establishing the levels at which humans might 

experience neurological effects from H2S exposure. The neurobehavioral endpoints that were 

evaluated are likely to be much more effective in capturing subtle neurological impairments that 

could not be detected in animal studies. 

49 Fiedler N., Kipen H., Ohman-Strickland P., Zhang J., Weisel C., Laumbach R., KellyMcNeil K., Olejeme K., and Lioy P. (2008). Sensory and Cognitive Effects of Acute Exposure 

to Hydrogen Sulfide. Env. Health Persp. 116(1):78-85. 

56 See American Mining Congress, supra, 907 F.2d at 1188 (data from 1980 rulemaking to 

list six wastes as “hazardous” under RCRA was inadequate as to certain of these wastes to 

support EPA’s 1988 relisting, necessitating remand). 

57 75 Fed. Reg. at 8893. 

EPA Response: Commenters provided an additional primary literature resource for the 

evaluation of hydrogen sulfide human health effects. However, the commenters mistakenly 

reported no significant changes between pre- and post-exposure performance. This is inaccurate 

as the authors identified significant impairment of verbal learning in all exposure groups 

(p≤.0.0003). Although the response was not dose dependent, the authors offer several 

explanations for this finding including a threshold effect for hydrogen sulfide as low as 0.05 

ppm. 

EPA’s Federal Register notice of Intent to Lift the Stay of the hydrogen sulfide reporting 

requirements specifically states that the human health concern for hydrogen sulfide is chronic 

human health effects (both upper respiratory and neurotoxic effects) (75 FR 8893, February 26, 

2010). As the commenters correctly pointed out, the Fiedler et al. study “Sensory and Cognitive 

Effects of Acute Exposure to Hydrogen Sulfide” evaluated only acute exposures – not chronic 

exposures. The study evaluated subjects exposed to hydrogen sulfide for ≤ 2 hours. Therefore, 

the study in question is not relevant to the chronic human health effects or the environmental 

effects that form the basis of EPA’s cited concerns for hydrogen sulfide.

While the Fiedler et al. study may be relevant in establishing the levels at which humans 

might experience neurological effects from acute hydrogen sulfide exposure, the Agency does 

not support the extension to chronic neurological effects. The Fiedler et al. study was designed 

to evaluate cognitive endpoints shown to be responsive in acute studies. As detailed in the 

Federal Register (75 FR 8891, February 26, 2010), hydrogen sulfide neurotoxicity is thought to 

occur due to hypoxia induced neuronal cell death. This pathology would not be evidenced in the 
57

short-term human study conducted by Fiedler et al. because the exposures were acute not 

chronic. Therefore, we would also conclude that the neurobehavioral endpoints that were used in 

the Fiedler et al. study are not, as the commenters 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 information that is not available in human 

studies. These types of studies provide powerful quantitative data, as evidenced in Skrajny, et 

al.(1992).

It should also be noted that the hydrogen sulfide inhalation exposure in the Fiedler et al.

study ranged from 0.05 to 5.0 ppm. This is far below the lowest observed adverse effect levels 

(LOAELs) seen in the animal studies of neurotoxicity cited in EPA’s notice of Intent to Lift the 

Stay and support materials. The Fiedler et al. study may indicate that hydrogen sulfide can cause 

adverse effects in humans at exposure levels (at least acute exposure levels) much lower than 

previously expected.

Comment:

B. EPA Has Not Considered New Information on Tissue Dosimetry in 

Determining the No Observed Adverse Effect Levels for Chronic 

Inhalation Exposure to H2S

The fact that no adverse effects were observed by Fiedler et al. (2008) in humans exposed 

to H2S at a concentration of 5 ppm is of particular interest because there are two other recent 

studies in which tissue dosimetry was utilized to establish a human equivalent concentration 

(HEC) based on the NOEL for nasal lesions in rats. Like the Fiedler study, these studies were not 

available when EPA completed its IRIS assessment for H2S in 2003. 

 In Schroeter, et al. (2006),58the authors used computational fluid dynamics (CFD) 

modeling to quantitatively correlate H2S tissue dosimetry in rat and human nasal passages. 

Assuming that equivalent H2S 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. 

In Schroeter, et al. (2010),59the authors investigated interhuman variability of H2S nasal 

dosimetry using anatomically accurate CFD models of the nasal passages of five adults and two 

children generated from magnetic resonance imaging (MRI) or computed tomography (CT) scan 

data. Using allometrically equivalent breathing rates, the authors simulated steady-state 

inspiratory airflow and H2S uptake. Approximate locations of olfactory epithelium were mapped 

in each model to compare air:tissue flux in the olfactory region among individuals. The fraction 

of total airflow to the olfactory region ranged from 2 percent to 16 percent. Despite this wide 

range in olfactory airflow, H2S 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. These preliminary results suggest that differences in 

nasal anatomy and ventilation among adults and children do not have a significant effect on H2S

dosimetry in the olfactory region. 
58

In combination, the Fiedler and Shroeter studies demonstrate that chronic human health 

effects are not likely at H2S concentrations of 5 ppm or below. This concentration is far above 

the ambient H2S concentrations from routine releases reported by EPA and PHS, as well as the 

various H2S standards established by individual states. 

58 Schroeter J.D., Kimbell J.S., Andersen M.E., and Dorman D.C. (2006). Use of a 

pharmacokinetic-driven computational fluid dynamics model to predict nasal extraction of 

hydrogen sulfide in rats and humans. Toxicol. Sci. 94(2):359-367. 

59 Schroeter J.D., Garcia G.J. M., and Kimbell, J.S. (2010). A computational fluid 

dynamics approach to assess interhuman variability in hydrogen sulfide nasal dosimetry. 

Inhalation Toxicol. 22(4): 277-286. 

EPA Response: The Agency would like to thank the commenters for bringing additional 

primary research studies to our attention, enabling us to make decisions using all available 

resources. EPA agrees with the commenters in regard to consideration of the dosimetry 

information presented in both papers by Schroeter et al. This type of pharmacokinetic modeling 

and the results presented represent the current state-of-the-science for inhalation dosimetry and 

are being reviewed by EPA for its utility in addressing our current reference concentration (RfC) 

derivation methods (see http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=212131). 

However, it is important to note that the purpose of the papers by Schroeter et al. was to provide 

a model-based NOAEL-HEC (5 ppm), not an alternative final RfC which incorporates the 

application of uncertainty factors. Thus, the only part of the EPA’s methods in deriving a value 

that is addressed is the calculation of an HEC extrapolated from animal data. No judgment is 

made by these authors that 5 ppm represents a replacement or alternative RfC or serves to 

replace or reduce the application of uncertainty factors. EPA's human health hazard assessment 

for hydrogen sulfide is based on the Agency’s current IRIS toxicological profile (Ref. 3), and 

while this new dosimetry information and resulting NOAEL-HEC might be considered in a 

revaluation of the current RfC, it does not impact EPA’s assessment of the potential for hydrogen 

sulfide to cause chronic toxicity.

The Agency does not concur with the commenter’s conclusion that the Fiedler and 

Shroeter studies demonstrate that chronic human health effects are not likely at hydrogen sulfide 

concentrations of 5 ppm or below. As noted, the Fiedler study addresses solely acute exposures 

and is not relevant to chronic effects. Further, the Schroeter reports only provide data for use in 

calculating the NOEAL-HEC based on pharmacokinetic modeling. Therefore, the commenter’s 

conclusions regarding chronic human health effects of hydrogen sulfide are not supported by the 

studies presented.

Comment:

IV. THERE IS NO NEED TO INCLUDE H2S AMONG THOSE SUBSTANCES SUBJECT 

TO TOXIC CHEMICAL RELEASE REPORTING REQUIREMENTS 

A. Although Accidental Releases of H2S Can Result in Serious Adverse Effects, 

Accidental Releases Are Subject to Emergency Notification Requirements under 
59

EPCRA Section 304

As explained above, emissions of H2S that would typically be reported under EPCRA 

Section 313 cannot be reasonably anticipated to cause any of the chronic health effects covered 

by EPCRA Section 313(d)(2)(B). In contrast, it is widely recognized that high level exposures to 

H2S that may occur as a consequence of industrial accidents may cause serious adverse health 

effects, including death. Accidental releases of potentially dangerous quantities of H2S are 

subject to the emergency notification requirements established by EPCRA Section 30460and by 

CERCLA Section 103.61 Such accidental releases are expressly regulated pursuant to CAA 

Section 112(r),62and H2S is among the substances that were specifically identified for such 

regulation by Congress in Section 112(r). 

B. Since There Is No Evidence That Would Suggest That Routine Releases of H2S 

Pose Any Risk, Nothing Would Be Achieved by Adding Reporting Requirements 

under EPCRA Section 313

Since emissions of H2S that would typically be reported under EPCRA Section 313 are 

irrelevant to potential chronic health effects of the type addressed by EPCRA Section 

313(d)(2)(B), and accidental releases of H2S that might be expected to present a potential hazard 

are well regulated under EPCRA Section 304, CERCLA Section 103, and CAA Section 112(r), 

the reporting that would be compelled by a listing for H2S under EPCRA Section 313 serves no 

purpose. Even if EPA has properly determined that H2S has “moderately high to high chronic 

toxicity,”63EPA is not required to list H2S in these circumstances. 

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).64 

The reviewing court that reviewed this construction expressly affirmed this conclusion, stating 

that “chemicals of moderate or high toxicity are not necessarily added [to the list] because of 

it.”65 

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. EPA should 

exercise its discretion to consider exposure factors in making a new listing determination for H2S 

and then rescind its prior listing determination. 

60 42 U.S.C. § 11004. 

61 42 U.S.C. § 9603. 

62 42 U.S.C. § 7412(r). 
60

63 75 Fed. Reg. at 8893.

64 59 Fed. Reg. at 61441-42. 

65 Troy Corp. v. Browner, 120 F.3d at 287. 

EPA Response: As EPA stated in response to the commenter’s previous comments on the 

releases of hydrogen sulfide, EPA does not agree that the commenter has shown that releases of 

hydrogen sulfide will not cause the kinds of health and environmental effects that EPA cited as 

support for listing hydrogen sulfide. Most importantly, EPA is not required to show that the 

effects that hydrogen sulfide can cause are actually occurring in order to list it on EPCRA section 

313. EPA notes that other commenters have provided comments alleging that they have 

experienced adverse health effects from hydrogen sulfide releases (see for example: EPA-HQTRI-2009-0844-0076, EPA-HQ-TRI-2009-0844-0081 in this document).

Regarding the fact that accidental releases of hydrogen sulfide that may cause serious 

adverse health effects including death are covered by other statutes, this has no impact on the 

listing of a chemical under EPCRA section 313. Listing of a chemical under EPCRA section 

313 is separate and apart from any other regulatory actions. EPCRA section 313 is focused on a 

community’s right-to-know about releases of toxic chemicals, not emergency reporting 

requirements for industrial accidents.

With regard to the commenter’s statements that listing hydrogen sulfide on EPCRA 

section 313 serves no purpose, the Agency disagrees. As EPA has stated:

It is important to understand that although an adverse effect is known or can be 

reasonably anticipated to be caused by a chemical on the section 313 list, a release of a 

chemical into a community does not necessarily mean that the effect will occur. 

Exposure and dose are also important factors in determining whether an adverse effect 

occurs and how serious the manifestation will be. The listing of a chemical on the 

section 313 list does not mean that a particular community will experience these adverse 

effects. Instead the purpose for listing a chemical is to ensure that the public gets 

information about releases of such chemicals. Thus, EPA believes that for chemicals that 

typically do not affect solely one or two species but rather affect changes across a whole 

ecosystem and for which there is well-documented evidence supporting the adverse 

effects, that their addition to the EPCRA section 313 list is warranted even though the

severity of the adverse effects that they induce will be dependent upon site-specific 

characteristics. Once EPA makes release data available through TRI, the community 

may then make its own determination on the importance of these releases (and their 

potential adverse effects).

[59 FR 61433, 11/30/1994 (emphasis added)].

Listing a chemical under EPCRA section 313 allows the public and governments to track 

and assess the impacts of chemical releases and make determinations as to whether or not a risk 

exists. Without release data, the public is limited in its ability to determine whether or not 

releases of a toxic chemical are impacting their health and/or environment. Even if releases are 

low and no adverse impacts are expected, that information is still of value to the public. 
61

The listing of hydrogen sulfide on EPCRA section 313 is consistent with EPA’s stated 

policy on the use of exposure assessments, which does not include the use of exposure for 

chemicals such as hydrogen sulfide that have moderately high to high human toxicity and high 

ecotoxicity. The commenter suggests that EPA should exercise its discretion with regard to the 

consideration of exposure, citing Troy Corp v. Browner for the proposition that “chemicals of 

moderate or high toxicity are not necessarily added [to the list] because of it.” Placed in greater 

context, that quotation is as follows:

The EPA's exposure policy merely informed the public that the agency would 

exercise its discretion by considering exposure only for low toxicity chemicals. 

The EPA did not thereby curtail this discretion; it did nothing more than clarify its 

own position. The policy does not impose rights or obligations or bind the agency 

to a particular result. Chemicals of low toxicity may be added despite the policy, 

just as chemicals of moderate or high toxicity are not necessarily added because 

of it.

[Troy Corp. v. Browner, 120 F.3d at 287.]

As the D.C. Circuit noted, EPA stated that it would exercise its discretion by considering 

exposure only for low toxicity chemicals. If EPA were to consider exposure for hydrogen 

sulfide it would be inconsistent with the Agency’s stated policy on the use of exposure 

assessments in EPCRA section 313 listing decisions. While EPA does have discretion to deviate 

from its policy, the Agency does not believe that there is any reason to consider exposure in its 

listing decision for hydrogen sulfide and thus has no reason to deviate from its stated exposure 

policy. 

Comment:

V. IF EPA DECIDES TO AFFIRM THE LISTING OF H2S UNDER EPCRA SECTION 

313 AND LIFT THE ADMINISTRATIVE STAY OF REPORTING REQUIREMENTS, 

EPA MUST PROVIDE ADDITIONAL GUIDANCE ON THE TIMING AND 

QUANTIFICATION OF REPORTING 

A. Since Procedures Are Not Currently in Place to Collect the Required Data 

on H2S Releases, Reporting Should Not Begin Until after a Full Year of 

Emissions Data Is Available

If EPA decides that it may lawfully affirm its prior listing determination for H2S and that 

it will proceed with its stated intention to lift the administrative stay, EPA must be careful to 

limit the potential impact on those entities that will be obligated to submit reports by establishing 

an appropriate transitional process. In particular, EPA should defer the first reporting cycle so 

affected entities can properly prepare for reporting. 

 EPCRA Section 313(d)(4)66establishes rules for determining when reporting obligations 

commence for any “revision” made to the list. Revisions made before December 1 of any 

calendar year “take effect” in the next calendar year and revisions made on or after December 1 

“take effect” in the calendar year after the next calendar year. EPA has implemented this 
62

provision by requiring the initial reports for a newly added chemical to include reportable 

releases during the calendar year when the revision “takes effect” and to be submitted no later 

than July 1 of the calendar year after that.

There is no logical reason to establish a transitional regime for reporting requirements 

that have been stayed since 1994 that is different than the transitional regime for a newly added 

substance. In each instance, affected facilities must have time for planning needed to measure, 

record, and document those releases that are subject to reporting. EPA has not clearly stated that 

a decision to reaffirm its prior listing decision for H2S and to lift the administrative stay of 

reporting requirements would be construed by EPA as a “revision” that falls within the scope of 

EPCRA Section 313(d)(4), and it should do so. If EPA were to decide to lift the administrative 

stay before December 1, 2010, the first reports due should cover releases during calendar year 

2011 and be due on or before July 1, 2012. If EPA were to decide to lift the administrative stay 

on or after December 1, 2010, but before December 1, 2011, the first reports due should cover 

releases during calendar year 2012 and be due on or before July 1, 2013. 

66 42 U.S.C. § 11023(d)(4).

EPA Response: EPA intends to treat the removal of the administrative stay of the EPCRA 

section 313 reporting requirements for hydrogen sulfide as it does a new chemical listing for the 

purposes of determining when reporting obligations commence. Therefore, the earliest that 

reporting would begin for hydrogen sulfide would be for reporting year 2012, with reports due 

July 1, 2013.

Comment:

B. EPA Should Be Prepared to Provide Guidance on Reportability

In the event that EPA decides to affirm its listing determination for H2S and to lift the 

administrative stay of reporting requirements, EPA should be prepared to provide guidance to 

industry sectors that may seek clarification on what constitutes a threshold quantity or a 

reportable release for H2S. Given the oxidation rate of dissolved H2S and the various ionized 

forms that are dependent on pH, this issue of reportability may be of particular concern to 

facilities with potential discharges to streams or water bodies.

EPA Response: EPA will provide guidance as necessary.
63

Commenter: The Natural Resources Defense Council [EPA-HQ-TRI-2009-0844-0088]

Comments on EPA’s “Hydrogen Sulfide; Community Right-to-Know Toxic Chemical 

Release Reporting” Intent to consider lifting administrative stay; opportunity for public 

comment, 75 Fed. Reg. 8,889 (Feb. 26, 2010). 

In its February 26, 2010 Federal Register notice, the Environmental Protection Agency 

(“EPA”) solicits comments on its proposal to lift the administrative stay of the Emergency 

Planning and Community Right-to-Know Act (“EPCRA”) section 313 toxic chemical release 

reporting requirements for hydrogen sulfide, a stay that has been in place for 16 years. See 75 

Fed. Reg. 8,889 et seq. (Feb. 26, 2010). EPA proposes to lift the administrative stay to require 

certain industries to report their emissions of hydrogen sulfide and their pollution prevention and 

recycling data. Id. at 8,890. The Natural Resources Defense Council (“NRDC”) is pleased to 

support EPA lifting the administrative stay, which has been in place for almost two decades. 

Hydrogen sulfide is a chemical emitted by, among other things, oil refineries, paper mills, 

chemical plants, natural gas processing plants, and sewage treatment plants. Lifting the 

administrative stay would require that these facilities report their emissions through the Toxics 

Release Inventory (“TRI”). Reporting this information would not only provide citizens, 

regulators, and industry with a clearer picture of industrial hydrogen sulfide emissions of the gas, 

but also would facilitate development of appropriate regulation of this chemical. The current state 

of the science on hydrogen sulfide validates EPA’s original TRI listing of the chemical in 1993. 

Moreover, the legal framework of EPCRA necessitates the removal of this stay. We commend 

EPA for finally taking action after 16 years to remove the stay. 

I. EPCRA background 

EPA developed the EPCRA TRI list to give the public access to information about 

chemical releases in their area. The TRI list is authorized by section 313 of EPCRA, which 

requires that “owners and operators of any particular facility that manufactures, processes, or 

otherwise uses a toxic chemical listed” on the TRI list report their emissions to EPA. 42 U.S.C. § 

11023(a). Since its development in the late 1980s, EPCRA has added hundreds of chemicals to 

the TRI list, bringing the total to approximately 650.1 EPA has increased the number of industries 

that are required to report their emissions and also requires that persistent, bioaccumulative, and 

toxic (PBT) chemicals report at a lower emissions threshold.2

EPCRA lays out specific criteria that must be met for a chemical to be added to the TRI 

list in section 313(d)(2) of the statute. There are three alternative avenues to listing: § 313 

(d)(2)(A) “acute human health effects” criteria, § 313 (d)(2)(B) “chronic human health effects” 

criteria, and § 313 (d)(2)(C) “environmental effects criteria.” Regardless of which subsection is 

used, § 313(d) states that a determination to list a chemical “shall be based on generally accepted 

scientific principles or laboratory tests, or appropriately designed and conducted epidemiological 

or other population studies, available to the Administrator.” Congress, in discussing this statutory 

standard, noted that: 

The purpose of [Section 313] is to inform the public which can be 

accomplished without very great burden on the reporting facility. Therefore, a 

decision to list a chemical for the purposes of reporting under this section can and 
64

should be made on the basis of less scientific evidence than would be needed to 

regulate its manufacture, use, or disposal. 

132 CONG. REC. S14,908 (1986) (Statement of Sen. Stafford). 

This expansive approach to listing chemicals under section 313 is necessary to meet the public 

disclosure goals of the statute. The list aims to provide the public with an understanding of the 

chemical emissions in their area. Moreover, this information acts to incentivize reductions in 

emissions, and provides public health agencies and researchers with information on exposure 

levels, which all ultimately drive the development of regulation.

II. History of Reporting of Hydrogen Sulfide Under the EPCRA TRI Rules 

On February 24, 1992, NRDC and then-Governor of New York Mario Cuomo filed a 

petition asking EPA to list 82 toxic chemicals on the EPCRA “section 313” list.3 All 82 of these 

chemicals, including hydrogen sulfide, were already listed at the time as toxic wastes under the 

Resource Conservation and Recovery Act’s (“RCRA”) “U list,” 40 C.F.R. § 261.33. Placement 

on the “U list” requires a finding that chemicals have been shown “in reliable scientific studies to 

cause chronic adverse health effects or have other hazardous characteristics.” 40 C.F.R. § 

261.11(a). The NRDC petition asserted that these “U list” placement standards were equal to, if 

not more stringent than, the requirements for listing under EPCRA’s 313 TRI rules which require 

only “generally accepted scientific principles or laboratory tests.”4 The American Petroleum 

Institute (“API”) wrote EPA to oppose the NRDC Petition before the agency had even taken 

action on the petition, stating that the petition did not meet the minimum scientific requirements 

of section 313.5

EPA issued a proposed TRI rule on September 8, 1992 partially granting the NRDC 

Petition and proposing to add 68 chemicals and 2 chemical categories to the EPCRA section 313 

list. In the proposed rule, EPA first noted that based on aquatic toxicity test data there was 

“sufficient evidence for listing hydrogen sulfide on EPCRA section 313 pursuant to EPCRA 

section 313(d)(2)(C) based upon the available ecotoxicity data for this chemical.” 57 Fed. Reg. 

41,020, 41,028 (Sept. 8, 1992). In addition to these environmental effects, EPA also found 

sufficient evidence for listing hydrogen sulfide on the 313 list based on “available respiratory 

toxicity data” pursuant to § 313(d)(2)(B), EPCRA’s “chronic human health effects” listing. Id. 

API and other industry groups took issue with the listing of hydrogen sulfide based on chronic 

human health effects, and instead stated that an analysis under §313(d)(2)(A)’s “acute effects” 

was more appropriate based on the science.6 EPA agreed with industry that “the respiratory and 

some of the neurotoxic effects reported in humans are most likely due to its acute effects.”7 EPA 

promulgated the final rule on December 1, 1993, and in doing so, listed hydrogen sulfide based on 

the statutory criteria found in both § 313(d)(2)(C) and § 313(d)(2)(B).8 With respect to listing 

under § 313(d)(2)(B)’s “chronic human health effects” criteria, EPA, in response to industry 

comments, based its finding on chronic neurotoxic effects, rather than the proposed rule’s finding 

based on respiratory effects, which EPA claimed in the interim to be more acute in nature.9

Industry groups expressed concern that they did not have an opportunity to comment on 
65

the changed basis for listing under § 313(d)(2)(B) from chronic respiratory effects in the proposed 

rule to chronic neurotoxic effects in the final rule and claimed that the Administrative Procedure 

Act had been violated. Despite the fact that EPA’s finding under § 313(d)(2)(C) of 

“environmental effects” was alone sufficient to place hydrogen sulfide on the EPCRA 313 list and 

require TRI reporting by industry, EPA decided to grant an administrative stay of the reporting 

requirements of the rule. On August 22, 1994, EPA published the administrative stay in the 

Federal Register stating it would “review new data and information made available subsequent to 

promulgation of the final rule.”10 The agency noted that the stay was authorized by “5 U.S.C. 

section 705, which provides that an agency may postpone the effective date of action taken by it 

when justice so requires, pending judicial review.”11 However, the agency also noted that no 

formal petition for review of the rule had actually been filed, although industry groups had 

purportedly told the agency that “unless administrative action is taken to resolve the issues 

outlined in today’s document, a prompt legal challenge will be brought.”12 Despite language in 

the notice indicating that EPA would make a “prompt” decision on the stay, and “soon,” the 

administrative stay has remained in place for almost 16 years. 

EPA’s recent Federal Register notice proposing to lift the stay points out that “by this 

current action, EPA is not revisiting the original listing decision, which was accomplished by 

final rule on December 1, 1993.”13 Further, the notice points out that while the science on 

hydrogen sulfide has been updated in the interim, “the listing decision was dictated by the acute 

aquatic toxicity finding alone under EPCRA section 313(d)(2)(C)” when the rule was finalized in 

December of 1993.14 In the current notice, EPA reiterates the correctness of listing hydrogen 

sulfide under both under § 313 (d)(2)(C) based on aquatic toxicity, and under § 313 (d)(2)(B) 

based on both respiratory and neurological effects. Both legal precedent and the updated body of 

science available on hydrogen sulfide support EPA’s removal of the administrative stay.

1 U.S. EPA, What is the Toxics Release Inventory (TRI) Program, http://www.epa.gov/TRI/triprogram/whatis.htm 

(last visited Apr. 16, 2010). 

2 Id. 

3 The Honorable Mario Cuomo, Governor of New York and the Natural Resources Defense Council, Petition to List 

82 Toxic Chemicals From the Resource Conservation and Recovery Act “U” List under Section 313 of the 

Emergency Planning and Community Right-To-Know-Act (Feb. 24, 1992) available at EPA Docket No. EPA-HQTRI-2005-0019-0425 ( hereinafter “NRDC Petition”). 

4 42 U.S.C. § 11023 (d). 

5 Letter from G. William Frick, Vice President, Health and Environment, American Petroleum Institute to EPA 

Docket Clerk (July 20, 1992) available at EPA Docket No. EPA-HQ-TRI-2005-0019-0424 (hereinafter “API 

Letter”). 

6 U.S. EPA, EPCRA Section 313 Petition to Add RCRA Chemicals and Responses to Rebuttal Comments on FR 

Notice , at 10 (Sept. 9, 1993) available at EPA Docket No. EPA-HQ-TRI-2005-0019-0400. 

7 Id. at 11 (emphasis added). 

8 Chemicals; Toxic Chemical Release Reporting; Community Right-to-know; Significant New Use Rule, 58 Fed. 

Reg. 63,500 et seq. (Dec. 1, 1993). 

9 Id. at 63,509. 

10 Hydrogen Sulfide; Methyl Mercaptan; Toxic Chemicals Release Reporting; Community Right-to-Know; Stay of 

Reporting Requirements, 59 Fed. Reg. 43,048 et seq. (Aug. 22, 1994). 

11 Id. at 43,050. 

12 Id. 

13 75 Fed. Reg. at 8889. 
66

14 Id. at 8891. 

Comment:

III. EPA Must Immediately Lift the Administrative Stay 

EPA should act immediately to lift the administrative stay of the reporting requirements 

for hydrogen sulfide under EPCRA. The stay was not only inappropriate at the time it was issued, 

but also the duration of the stay violates foundational principles of administrative law. 

In particular, and most glaringly, the original stay issued under 5 U.S.C. § 705 of the 

Administrative Procedure Act (“APA”) to defer the reporting requirements circumvented 

traditional rulemaking processes. The full text of the statute EPA cited to in 1993 for deferring 

reporting requirements of hydrogen sulfide reads: 

When an agency finds that justice so requires, it may postpone the 

effective date of action taken by it, pending judicial review. On such conditions as 

may be required and to the extent necessary to prevent irreparable injury, the 

reviewing court, including the court to which a case may be taken on appeal from 

or on application for certiorari or other writ to a reviewing court, may issue all 

necessary and appropriate process to postpone the effective date of an agency 

action or to preserve status or rights pending conclusion of the review proceedings 

5 U.S.C. § 705 

In reading this section in context, it becomes apparent that the Administrative Procedure Act did 

not intend this part of the Act to be used to circumvent traditional rulemaking processes. Rather, 

the section clearly contemplates the option of staying the rule specifically during the pendency of 

litigation, to avoid harm to parties affected by the action. In this way the rule complements and 

promotes the administrative rulemaking process. EPA nonetheless stayed the hydrogen sulfide 

reporting requirements in the absence of any pending judicial review. Were EPA to simply stay 

indefinitely any rule that prompted industry concern, the entire regulatory capacity of the agency 

would grind to a halt. Parties must challenge rulemakings in court to halt lawfully adopted rules, 

rather than exerting pressure on the issuing agency. This well-understood practice protects the 

rulemaking process from inappropriate influence and allows for timely disposition of issues. It 

also protects the public against the improper blockage of lawfully adopted rules based on political 

or powerful interest group complaints. 

In case law relating to an agency’s use of this provision of the APA to stay its own rule, 

courts note that these stays are implemented during the pendency of judicial review, and not at the 

agency’s whim in the face of industry criticism.15 In this sense, the courts analogize a stay under 5 

U.S.C. § 705 to a preliminary injunction, where the rule is stayed to avoid harm until the issue is 

resolved.16

Moreover, the D.C. Circuit has specifically rejected EPA’s ability to drag out administrative 

stays. NRDC v. Reilly presents an analogous situation, where EPA in 1979 added radionuclides to 
67

the Clean Air Act’s list of hazardous air pollutants.17 The agency was required to promulgate 

emission standards within 180 days of this listing, and failed to do so until 1985 in violation of 

numerous court orders. Despite this, the Agency stayed its own implementation of the standards, 

purportedly because it had received adverse comments from other federal agencies about the 

impact that the emissions standards would have. The agency then “concluded that it should treat 

the comments and information filed by [the National Institute of Health] and NRC as petitions for 

reconsideration of the standard.”18 The Clean Air Act, in section 307, specifically states that an 

administrative stay may be implemented for up to a period of three months.19 The agency 

attempted to further extend a stay issued under section 307 of the Clean Air Act through the use 

of the general authority found in section 301 of the Clean Air Act, and 5 U.S.C. § 705, the 

authority relied on for the hydrogen sulfide administrative stay. The court rejected EPA’s ability 

to drag out rulemaking based on these general provisions, and vacated the stay. Though NRDC v. 

Reilly dealt with the specific provision for administrative stays under the Clean Air Act, the time 

it took for the agency to promulgate regulations clearly colored the court’s view. As applied to 

hydrogen sulfide, both the duration of the stay and the fact that there was no pending litigation 

regarding the reporting requirements speak to the impropriety of the stay both at its inception and 

for its duration. Both of these factors speak to the importance of EPA’s immediate removal of the 

administrative stay. In addition to the legal necessity of lifting the administrative stay, current 

science supports EPA’s 1993 finding that hydrogen sulfide should be listed on the TRI section 

313 list. 

15 See, e.g., Bakersfield City School Dist. of Kern County v. Boyer, 610 F.2d 621, 624 (9th Cir. 1979) (“The agency 

or the court may postpone or stay agency action pending such judicial review”). 

16 See, e.g., State of Ohio ex rel. Celebrezze v. Nuclear Regulatory Com'n, 812 F.2d 288 (6th Cir. 1987). 

17 976 F.2d 36 (D.C. Cir. 1992). 

18 Id. at 38 (quoting 54 Fed.Reg. 51,654, 51,668 (1989)). 

19 42 U.S.C. § 7607(d)(7)(B) (“The effectiveness of the rule may be stayed during such reconsideration, however, 

by the Administrator or the court for a period not to exceed three months.”).

EPA Response:

 Commenter states that: “EPA should act immediately to lift the administrative stay of the 

reporting requirements for hydrogen sulfide under EPCRA. The stay was not only inappropriate 

at the time it was issued, but also the duration of the stay violates foundational principles of 

administrative law.”

EPA appreciates the commenter’s support of the lifting of the administrative stay of the 

EPCRA section 313 reporting requirements for hydrogen sulfide.

The delay in taking action on the administrative stay of the EPCRA section 313 reporting 

requirements was a combination of competing actions, resources, and administration priorities.

The 1994 stay of the hydrogen sulfide reporting requirements was never administratively 

or judicially challenged, and comments on the legal propriety of issuing the stay in 1994 are 

beyond the scope of this action.
68

Comment:

IV. Scientific studies on the impact of hydrogen sulfide 

a. Hydrogen sulfide background

Hydrogen sulfide is a flammable gas that occurs in petroleum and coal deposits. It is also 

produced by the anaerobic decomposition of organic matter, by industrial processes and by a 

variety of natural sources. Industrial and agricultural sources of hydrogen sulfide include the 

petroleum refining and natural gas industries, coke oven plants, kraft paper mills, tanneries, swine 

containment and manure treatment facilities, and wastewater treatment facilities.20 Humans begin 

to detect the odor of hydrogen sulfide at concentrations of 0.0005 to 0.3 parts per million (ppm), 

but may lose their ability to detect it at concentrations above 100 ppm due to olfactory tissue 

damage.21 Hydrogen sulfide concentrations in air in non-polluted areas range from 0.11 to 0.33 

parts per billion (ppb),22 but concentrations above 90 ppb (0.09 ppm) have been measured in 

residential areas near natural or industrial sources.23 

Few studies have analyzed hydrogen sulfide concentrations in outdoor ambient air in areas 

near emission sources. In Dakota City and Sioux City Nebraska, hydrogen sulfide concentrations 

of >1 ppm were measured 275 times from 1995 to 1999.24 These concentrations exceed the 

Minimal Risk Level (MRL) of 0.02 ppm established by the Agency for Toxic Substances and 

Disease Registry (ATSDR). The MRL is an estimate of daily human exposure to a hazardous 

substance that is likely to be without an appreciable risk of adverse noncancer health effects over 

a specified route and duration of exposure.25 They are also above the World Health Organization 

(WHO) air quality guideline of 150 μg/m3 (roughly equivalent to 0.1 ppm), and the EPA 

Reference Concentration of 2x10 mg/m (0.001 ppm).26 Sources of hydrogen sulfide in the area 

include a beef slaughter facility, a leather tanning facility, a wastewater lagoon, and municipal 

wastewater treatment plants.27

Natural gas wells may also release large quantities of hydrogen sulfide. Leahey and 

Schroeder (1986) estimated hydrogen sulfide concentrations of 2 ppm and 14 ppm downwind of 

two sour gas well blowouts.28

b. Adverse effects on human health 

The harmful effects of hydrogen sulfide exposure have been well documented. Hydrogen 

sulfide interferes with oxidative metabolism and adversely affects the respiratory, nervous, and 

cardiovascular systems. High airborne concentrations (> 50 ppm) lead to unconsciousness and 

death.29 Much of the data on human health effects comes from case studies of occupational 

exposures to high concentrations resulting in poisoning. However, animal studies provide 

important information on health effects from short-and medium-term low-level exposures that 

may be more relevant to populations living near emissions sources and to workers regularly 

exposed to low concentrations. These include metabolic, respiratory, neurological, reproductive, 

and developmental effects. In guinea pigs, fatigue, drowsiness, dizziness, ocular irritation and a 

reduction in brain tissue lipids were observed as a result of exposure to 20 ppm for 1 hour per day 

for 11 days.30 Olfactory neuron loss and basal cell hyperplasia were reported in rats exposed to 

≥30 ppm hydrogen sulfide 6 hours/day for 10 weeks.31
69

Several animal studies have also found adverse reproductive and developmental effects 

associated with the inhalation of low levels of hydrogen sulfide. In one study, the flaring of sour 

gas containing hydrogen sulfide from oil and natural gas wells was associated with stillbirth and 

calf mortality in cow herds in western Canada.32 A study of pregnant rats found statistically 

significant increases in blood glucose levels in animals exposed to concentrations of 20 to 75 

ppm.33 A subsequent study by the same researchers also found an increase in parturition times in 

dams exposed to ≥20 ppm hydrogen sulfide, and decreased time for pinna detachment and hair 

growth in the pups.34 Other developmental effects observed in laboratory studies include 

alterations in Purkinje cell dendritic fields in rat pups exposed to 20 or 50 ppm hydrogen sulfide,35

and reductions in the amino acid levels in the brain (Hannah et al. 1989).36 Overall, rodents 

appear to be less sensitive to the effects of hydrogen sulfide than humans.37 Therefore, effects 

may occur in exposed human populations at lower concentrations that may not produce effects in 

rodent studies. 

Some human studies have investigated the effects of controlled short exposures to low 

concentrations of hydrogen sulfide. A study of asthmatics found that bronchial obstruction 

occurred in some asthmatic individuals after exposure to hydrogen sulfide at a concentration of 2 

ppm for 30 minutes.38 Other studies indicate that short exposure to 5 ppm hydrogen sulfide 

increased lactate levels in the blood in healthy individuals performing submaximal and maximal 

exercise.39,40

Human occupational and epidemiological evidence indicates that long-term hydrogen 

sulfide exposure in humans is associated with neurological, ocular, respiratory, and reproductive 

effects. Oil shale industry workers exposed to hydrogen sulfide concentrations in excess of 20 

ppm experienced symptoms including fatigue, dizziness and poor memory.41 Bates et al. (1997, 

1998) studied the incidence of nervous system and other diseases in Rotorua, New Zealand, 

where residents were exposed to a median concentration of 21 ppb hydrogen sulfide/m3 air from 

geothermal sources and found a statistically significant increase in infant cerebral palsy, other 

diseases of the brain, migraine, and mononeuritis. Cataracts and diseases of the conjunctiva and 

eye orbit were also increased.42,43 In South Karelia, Finland, exposure to sulfur gases including 

hydrogen sulfide (annual mean concentration 0.006 ppm; daily maximum 0.007 ppm) emitted by 

pulp mill operations was associated with a higher incidence of eye and respiratory symptoms: the 

incidence of eye symptoms was increased 11.7 times and the incidence of nasal symptoms was 

doubled in the exposed population relative to people living in non-polluted areas.44 An 

occupational study of rayon workers at a viscose rayon plant also found ocular effects; there was 

a statistically significant increase in eye pain, burning and photophobia from exposure to 

hydrogen sulfide and/or carbon disulfide.45 

Occupational exposure to hydrogen sulfide may also be associated with higher rates of 

miscarriage. Researchers have reported a statistically significant increase in rates of miscarriage 

in women working in rayon textile and paper products plants in Finland who were exposed to 

hydrogen sulfide, sulfur dioxide, and carbon disulfide gases; the same was true for women whose 

husbands worked in those types of jobs. In the same study, higher miscarriage rates were also 

found in areas with airborne concentrations of hydrogen sulfide above 0.003 ppm, although these 

did not reach statistical significance.46 Significantly higher miscarriage rates were also reported 

for women working in petrochemical facilities in China, with hydrogen sulfide exposure 
70

associated with a two-fold increase in miscarriages.47 Kilburn and Warshaw (1995) found a 

higher incidence of neurophysiological deficits in people who worked or lived downwind of a 

California sour crude oil refinery who were exposed to hydrogen sulfide and other reduced sulfur 

gases.48

Campagna et al. (2004) found an association between high levels of hydrogen sulfide and 

increased hospital visits for asthma and all respiratory diseases in Sioux City and Dakota City, 

Nebraska. Although there are few other studies that systematically examine low-level, long-term 

exposures to humans living near sources emitting large amounts of hydrogen sulfide, these 

findings raise concerns about the effects of chronic exposure in sensitive subpopulations such as 

children, the elderly, and people with respiratory conditions living near sources of hydrogen 

sulfide emissions.

20 Agency for Toxic Substances and Disease Registry (ATSDR). 2006. Toxicological Profile for Hydrogen Sulfide 

(Update). Atlanta, GA: U.S. Department of Health and Human Services, Public Health Service. 

21 Agency for Toxic Substances and Disease Registry (ATSDR). 2006. Toxicological Profile for Hydrogen Sulfide 

(Update). Atlanta, GA: U.S. Department of Health and Human Services, Public Health Service.22 EPA. 1993. 

Report to Congress on hydrogen sulfide air emissions associated with the extraction of oil and natural gas. Research 

Triangle Park, NC: U.S. Environmental Protection Agency, Office of Air Quality Planning and Standards. 

EPA453R93045. PB94131224. 

23 Agency for Toxic Substances and Disease Registry (ATSDR). 2006. Toxicological Profile for Hydrogen Sulfide 

(Update). Atlanta, GA: U.S. Department of Health and Human Services, Public Health Service. 

24 Inserra SG, Phifer BL, Anger WK, et al. 2004. Neurobehavioral evaluation for a community with chronic 

exposure to hydrogen sulfide gas. Environ Res 95:53-61. 

25 Agency for Toxic Substances and Disease Registry (ATSDR). 2006. Toxicological Profile for Hydrogen Sulfide 

(Update). Atlanta, GA: U.S. Department of Health and Human Services, Public Health Service. 

26 World Health Organization (2003) Concise International Chemical Assessment Document 53, Hydrogen Sulfide: 

Human Health Aspects. Geneva, Switzerland: World Health Organization. 

27 Campagna D, Kathman SJ, Pierson R, et al. 2004. Ambient hydrogen sulfide, total reduced sulfur, and hospital 

visits for respiratory diseases in northeast Nebraska, 1988-2000. J Expo Anal Environ Epidemiol 14(2):180-187. 

28 Leahey DM, Schroeder MB (1986) Predictions of maximum groundlevel hydrogen sulfide concentrations 

resulting from two sour gas well blowouts. Journal of the Air Pollution Control Association, 36:1147–1149.29 

Kilburn KH, Warshaw RH. Hydrogen sulfide and reduced-sulfur gases adversely affect neurophysiological functions. 

Toxicol Ind Health. 1995 Mar-Apr;11(2):185-97. 

30 Haider SS, Hasan M, Islam F (1980) Effect of air pollutant hydrogen sulfide on the levels of total lipids, 

phospholipids & cholesterol in different regions of the guineapig brain. Indian Journal of Experimental Biology, 

18:418–420. 

31 Brenneman KA, James RA, Gross EA, et al. 2000. Olfactory neuron loss in adult male CD rats following 

subchronic inhalation exposure to hydrogen sulfide. Toxicol Pathol 28(2):326-333. 

32 Waldner CL, Ribble CS, Janzen ED, Campbell JR.Associations between oil-and gas-well sites, processing 

facilities, flaring, and beef cattle reproduction and calf mortality in western Canada. Prev Vet Med. 2001 Jul 19;50(1-

2):1-17. 

33 Hayden LJ, Goeden H, Roth SH (1990a) Exposure to low levels of hydrogen sulfide elevates circulating glucose 

in maternal rats. Journal of Toxicology and Environmental Health, 31:45–52. 

34 Hayden LJ, Goeden H, Roth SH. 1990b. Growth and development in the rat during sub-chronic exposure to low 

levels of hydrogen sulfide. Toxicol Ind Health 6:389-401. 

35 Hannah RS, Roth SH (1991) Chronic exposure to low concentrations of hydrogen sulfide produces abnormal 

growth in developing cerebellar Purkinje cells. Neuroscience Letters, 122:225–228. 

36 Hannah RS, Roth SH (1991) Chronic exposure to low concentrations of hydrogen sulfide produces abnormal 

growth in developing cerebellar Purkinje cells. Neuroscience Letters, 122:225–228. 

37 World Health Organization (2003) Concise International Chemical Assessment Document 53, Hydrogen Sulfide: 

Human Health Aspects. Geneva, Switzerland: World Health Organization. 

38 Jappinen P, Vilkka V, Marttila O, Haahtela T (1990) Exposure to hydrogen sulphide and respiratory function. 
71

British Journal of Industrial Medicine, 47:824–828. 

39 Bhambhani Y, Singh M (1991) Physiological effects of hydrogen sulfide inhalation during exercise in healthy 

men. Journal of Applied Physiology, 71:1872–1877. 

40 Bhambhani Y, Burnham R, Snydmiller G, MacLean I, Martin T. Effects of 5 ppm hydrogen sulfide inhalation on 

biochemical properties of skeletal muscle in exercising men and women. Am Ind Hyg Assoc J. 1996 May;57(5):464-8

41 Ahlborg G (1951) Hydrogen sulfide poisoning in shale oil industry. Archives of Industrial Hygiene and 

Occupational Medicine, 3:247– 266. 

42 Bates MN, Garrett N, Graham B, Read D (1997) Air pollution and mortality in the Rotorua geothermal area. 

Australia and New Zealand Journal of Public Health, 21:581–586. 

43 Bates MN, Garrett N, Graham B, Read D (1998) Cancer incidence, morbidity and geothermal air pollution in 

Rotorua, New Zealand. International Journal of Epidemiology, 27:10–14. 

44 Jaakkola JJ, Vilkka V, Marttila O, Jappinen P, Haahtela T (1990) The South Karelia Air Pollution Study: the 

effects of malodorous sulfur compounds from pulp mills on respiratory and other symptoms. American Review of 

Respiratory Diseases, 142:1344–1350. 

45 Vanhoorne M, de Rouck A, de Bacquer D. Epidemiological study of eye irritation by hydrogen sulphide and/or 

carbon disulphide exposure in viscose rayon workers. Ann Occup Hyg. 1995 Jun;39(3):307-15. 

46 Hemminki K, Niemi ML (1982) Community study of spontaneous abortions: relation to occupation and air 

pollution by sulfur dioxide, hydrogen sulfide, and carbon disulfide. International Archives of Occupational and 

Environmental Health, 51:55–63. 

47 Xu X, Cho SI, Sammel M, You L, Cui S, Huang Y, Ma G, Padungtod C, Pothier L, Niu T, Christiani D, Smith T, 

Ryan L, Wang L (1998) Association of petrochemical exposure with spontaneous abortion. Occupational and 

Environmental Medicine, 55:31–36. 

48 Kilburn KH, Warshaw RH. Hydrogen sulfide and reduced-sulfur gases adversely affect neurophysiological 

functions. Toxicol Ind Health. 1995 Mar-Apr;11(2):185-97.49 Thompson, CR, and Kats, G. 1978. Effects of 

continuous H2S fumigation on crop and forest plants. Environmental Science & Technology 12(5):550-3.

EPA Response: The commenter has provided a summary of the chemical properties and hazards 

of hydrogen sulfide, much of which supports EPA’s conclusion that the administrative stay of the 

reporting requirements for hydrogen sulfide should be lifted.

Comment:

 

 c. Adverse ecological effects 

There is ample evidence that exposure to hydrogen sulfide at low concentrations harms 

plants and animals. A study by researchers at the University of California demonstrated that 

continuous exposure to as little as 0.3 ppm hydrogen sulfide can reduce growth and/or cause foliar 

damage in alfalfa, grapes, lettuce, ponderosa pine and Douglas fir, and reduce the sugar content in 

sugar beet roots. At 3 ppm, hydrogen sulfide causes defoliation in California buckeye and death 

of alfalfa plants. This study indicated that rapidly growing species suffered damage at lower 

concentrations than other species.49

Hydrogen sulfide has been shown to impair growth and cause mortality at low 

concentrations in aquatic animals as well. Studies suggest its toxicity increases at lower oxygen 

levels and higher pH. For example, the LC50 for goldfish is 0.062 and 0.048 mg/L hydrogen 

sulfide at oxygen concentrations of 6 and 1.5 mg/L, respectively.50 Furthermore, LC50s ranging 

from 0.057 mg/L to 0.0149 mg/L have been reported for fathead minnows at pH ranging from 7.1 

to 8.7.51

Even exposure at sublethal levels may have deleterious effects on fish and aquatic 
72

invertebrates. While a concentration of 0.5 mg/L in channel catfish caused respiratory arrest, but 

a concentration of only 0.1 mg/L inhibits cytochrome oxidase activity in the brain by 40 percent.52

Smith et al. (1976) reported a 96-hour LC50 of 0.0243 mg/L for juvenile fathead minnow but 

found that chronic exposure at 0.004 mg/L reduced growth, survival and reproduction.53 In 

bluegill fish, the maximum no-effect concentration for chronic exposure was 0.0004 mg/L;54 it 

has been reported that chronic exposure to hydrogen sulfide above this level decreases swimming 

endurance in these fish.55 Oseid and Smith (1978) found a 96-hour LC50 for mayfly nymphs of 

the species Hexagenia limbata – which live in water at the nymph stage – of 0.165 mg/L, but 

chronic exposure at 0.0762 mg/L for 138 days caused 100% mortality. Furthermore, no 

subimagos emerged at concentrations above 0.0348 mg/L, a concentration about one fifth of the 

LC50.

56 No-effect concentrations for chronic exposure in some species may be as little as 8 

percent of the 96-hour LC50.

57

Sensitivity to the toxic effects of hydrogen sulfide varies by species and life stage. Of 

eight invertebrate species tested by Smith et al. (1977), a mayfly of the genus Baetis was the most 

sensitive, with a 96-hour LC50 of 0.020 mg/L, a concentration fifty times lower than the LC50 for 

the least sensitive invertebrate in the study, Assellus, which had an LC50 of 1.07 mg/L.58 This 

study also indicates that the lethal threshold concentration for different species of juvenile fish 

may differ by an order of magnitude. Juveniles of seven fish species were tested in the study for 

acute toxicity of hydrogen sulfide and the lethal threshold ranged from 0.0087 mg/L in rainbow 

trout to 0.0840 mg/L in goldfish. Higher sensitivity was observed in fry than in juvenile fish.59 

The same researchers state that hydrogen sulfide concentrations above 0.025 mg/L are associated 

with decreased size and survival of fish fry.60 

49 Thompson, CR, and Kats, G. 1978. Effects of continuous H2S fumigation on crop and forest plants. 

Environmental Science & Technology 12(5):550-3. 

50 Adelman, I. R. and Smith LL Jr. 1972. Toxicity of hydrogen sulfide to goldfish carassius-auratus as influenced 

by temperature oxygen and bioassay techniques. Journal of the Fisheries Research Board of Canada 29(9):1309-17. 

51 Broderius S. J. Smith LL Jr. 1976 Effect of hydrogen sulfide on fish and invertebrates Part II.Hydrogen sulfide 

determination and relationship between pH and sulfide toxicity. Duluth, MN: U.S. Environmental Protection Agency, 

Environmental Research Lab. EPA Document Number EPA-600/3-76-0626. 

52 Torrans EL, Clemens HP. 1981. Hysiological and biochemical effects of exposure to fish of hydrogen sulfide. 

Comparative Biochemistry and Physiology, Part C: Comparative Pharmacology 71(2):183-90. 

53 Smith, L. L., Jr., Oseid, D. M., and Olson, L. E., Acute and chronic toxicity of hydrogen sulfide to the fathead 

minnow, Pimephales promelas. Environmental Science & Technology 10(6):565-568. 

54 Smith LL Jr., Oseid DM, Adelman IR, Broderius SJ. 1977. Effects of hydrogen sulfide on fish and invertebrates. 

Part 1, Acute and Chronic Toxicity Studies. EPA Document Number 600/3-76-062.55 Oseid D. and Smith LL Jr. 

(1972) Swimming endurance and resistance to copper and malathion of bluegills treated by longterm exposure to 

sublethal levels of hydrogen sulfide. Transactions of the American Fisheries Society 101:620-5. 

56 Oseid D. M., and Smith LL Jr 1975. Long-term effects of hydrogen sulphide on Hexagenia limbata 

(Ephemeroptera). Environmental Entomology 4: 15-18. 

57 Oseid D. and Smith LL Jr. 1974. Factors influencing acute toxicity estimates of hydrogen sulfide to freshwater 

invetrtebrates. Water Research 8(10):739-46. 

58 Smith LL Jr, Oseid DM, Adelman IR, Broderius SJ. 1977. Effects of hydrogen sulfide on fish and invertebrates. 

Part 1, Acute and Chronic Toxicity Studies. EPA Document Number 600/3-76-062. 

59 Id. 

60 Smith LL Jr, Osied DM. 1972. Effects of hydrogen sulfide on fish eggs and fry. Water Research 6(6):711-20.

EPA Response: The commenter has provided a summary of the ecological hazards of hydrogen 

sulfide, some of which is the same as in EPA’s own assessment and others are additional studies. 
73

EPA believes the information supports EPA’s conclusion that the administrative stay of the 

reporting requirements for hydrogen sulfide should be lifted.

Comment:

V. Regulation of hydrogen sulfide under other statutes

In light of the scientific evidence on the damage hydrogen sulfide can do to both the environment 

and human health, it is not surprising that hydrogen sulfide is regulated outside of the TRI 

program. At the federal level, EPA regulates hydrogen sulfide under the accidental release 

provisions of section 112(r) of the Clean Air Act, but a number of environmental groups have 

recently petitioned EPA to regulate the chemical under section 112(b), as a hazardous air 

pollutant (“HAP”) as well. Similar to the TRI reporting requirements, environmental groups 

petitioned EPA 11 years ago to list hydrogen sulfide as HAP, and EPA never acted on the 

petition. In March of 2009, these same groups renewed their petition, again asking EPA to 

regulate hydrogen sulfide not only under section 112(r) but also under 112(b).61 As pointed out in 

the letter, 34 states have ambient air standards that address hydrogen sulfide, yet still these 

standards do not fully protect citizens from potential exposure to dangerously high levels of this 

gas. On another front, environmental groups filed a petition in September of 2009 to regulate 

Concentrated Animal Feeding Operations (“CAFOs”) through New Source Performance 

Standards (“NSPS”) for greenhouse gases and establish emissions limits for gases such as 

hydrogen sulfide.62 This suite of regulatory petitions and state standards speak to the importance 

of EPA lifting the administrative stay for TRI reporting. Hydrogen sulfide is a chemical of great 

concern in a variety of industrial settings, and better information on emissions from the TRI list 

will aid in crafting and strengthening both existing and new regulations.

61 Letter from Sierra Club, ET AL. to Lisa Jackson, Administrator, U.S. EPA (March 30, 2009) available at 

http://www.earthworksaction.org/pubs/H2SLetterToEPA.pdf (last visited Apr. 29, 2010). 

62 Humane Society, ET AL., Petition to List Concentrated Animal Feeding Operations under Clean Air Act Section 

111(B)(1)(A) of the Clean Air Act, and to promulgate standards of performance under Clean Air Act Sections 

111(B)(1)(B) and 111(d) (Sept. 21, 2009) available at 

http://www.foe.org/sites/default/files/HSUS_et_al_v_EPA_CAFO_CAA_Petition.pdf (last visited Apr. 29, 2010) 

EPA Response: EPA will respond to the commenter’s cited requests for regulation under other 

programs at the appropriate time and through the processes established for those other programs.

Comment:

VI. Environmental Justice Concerns 

As noted above, hydrogen sulfide is emitted by a number of different industries in 

significant amounts. As is true of most industrial emissions, communities living near industrial 

sources such as refineries, paper mills, and sewage treatment plants that emit large amounts of 

hydrogen sulfide, are disproportionately affected by the neurotoxic and respiratory problems 

associated with exposure to the gas. In light of this, environmental justice concerns with the 

continually unreported emissions of hydrogen sulfide are especially grave. Without access to 

information on emissions from facilities near environmental justice communities, these 

communities cannot protect themselves and are denied knowledge about the air they are 
74

breathing. Moreover, continued research of hydrogen sulfide and its health effects and advocacy 

for regulation will also be significantly impaired.

EPA Response: While not a statutory criteria for listing, environmental justice concerns are an 

important consideration. By lifting the stay of the EPCRA section 313 reporting requirements for 

hydrogen sulfide, EPA would be providing communities across the United States (including 

minority populations and low income populations) with access to data which they may use to seek 

lower exposures and consequently reductions in chemical risks for themselves and their children. 

This information can also be used by government agencies and others to identify potential 

problems, set priorities, and take appropriate steps to reduce any potential risks to human health 

and the environment. Therefore, the informational benefits of lifting the stay will have a positive 

impact on the human health and environmental impacts of minority populations, low-income 

populations, and children. 

Comment:

VII. Conclusion 

We commend EPA on its decision to take long-overdue action lifting the administrative 

stay of reporting requirements for hydrogen sulfide under EPCRA’s TRI program. For the past 16 

years, while emissions of this gas have gone unreported, the science has continued to develop. 

The danger that emissions pose to human health are clear, and there is no legal justification for 

continuing the stay. Not only was the stay inappropriate when issued, but now, industries who 

would have had to report their emissions have had 16 years to prepare for these requirements, 

diminishing any claim of burdens to industry. With the support of both science and the law, EPA 

must now require that emissions of hydrogen sulfide be reported under the EPCRA TRI program. 

Particularly sensitive environmental justice communities living near industrial facilities emitting 

large amounts of potentially toxic hydrogen sulfide gas should have access to information on the 

air they are breathing. Reporting requirements will facilitate regulatory action with respect to 

emissions of hydrogen sulfide, and protect public health.

EPA Response: EPA appreciates the commenter’s support for lifting the stay of the EPCRA 

section 313 reporting requirements for hydrogen sulfide.
75

Commenter: Mary Ann Johnson [EPA-HQ-TRI-2009-0844-0089]

Mary Johnson 

<frazledgrams59@yahoo.c

om>

05/12/2010 03:44 PM

To Docket OEI@EPA

cc

bcc

Subject H2S reporting

I am writing in response to Docket ID # EPA-HQ-TRI-2009-0844. I feel that the public has the 

right to know when poison gases are being released into the air that we breathe. Those poisons 

should be controlled. It is very cheep for the gas companies to treat the wells that have H2S 

emissions. They should be required to treat those wells frequently so that no poison is emitted 

into the air. 

Sincerely

Mary Ann Johnson

EPA Response: EPA appreciates the commenter’s support of the lifting of the administrative 

stay of the EPCRA section 313 reporting requirements for hydrogen sulfide. 
76

Commenter: National Association of Clean Water Agencies [EPA-HQ-TRI-2009-0844-0090]

May 12, 2010

Office of Environmental Information Docket 

U.S. Environmental Protection Agency 

1200 Pennsylvania Ave, NW 

Washington, DC 20460 

Via Email: oei.docket@epa.gov

Re: Docket ID No. EPA-HQ-TRI-2009-0844

The National Association of Clean Water Agencies (NACWA) appreciates the opportunity to 

comment on EPA’s notice of Intent to Consider 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. NACWA represents the interests of nearly 

300 publicly owned wastewater treatment agencies nationwide, serving the majority of the 

sewered population in the U.S. Hydrogen sulfide is a concern for publicly owned treatment 

works (POTWs) since it can be emitted during the wastewater treatment processes and from the 

collection systems that convey wastewater to the treatment plant.

NACWA is not commenting on the science behind EPA’s conclusions that support lifting the 

Administrative Stay of the Toxics Release Inventory (TRI) reporting requirements for hydrogen 

sulfide. NACWA is concerned, however, that EPA may decide to add hydrogen sulfide to the 

Clean Air Act section 112(b) Hazardous Air Pollutants (HAPs) list after it is added to the TRI 

list. This action could have a significant effect on POTWs. Depending on the size of the POTW, 

the extent of its tributary collection system, and the other characteristics of the wastewater flow, 

a POTW could be classified as a major source of hydrogen sulfide. This could lead to maximum 

achievable control technology (MACT) requirements, which could require POTWs to cover 

portions of their treatment plants, address emissions from hundreds of miles of conveyance 

system piping, and potentially capture and treat emissions.

NACWA was heavily involved in the seven years of negotiations that resulted in the Subpart 

VVV POTW MACT standards. During that time, NACWA raised concerns about the feasibility 

of controlling hydrogen sulfide in widespread collection systems over which POTWs have little 

or no control. NACWA remains very concerned about the feasibility of these potential 

requirements for hydrogen sulfide controls. 

If EPA lifts the Administrative Stay on reporting requirements for hydrogen sulfide, NACWA 

recommends that the Agency carefully consider the consequences of any future regulations for 

hydrogen sulfide. In particular, EPA should consider the potential burden on POTWs of 

complying with the MACT standard if hydrogen sulfide is listed as a HAP under section 112(b) 

of the CAA. 
77

Thank you for consideration of our comments. Please contact me at 202/2969836 or 

cfinley@nacwa.orgif you have any questions. 

Sincerely, 

Cynthia A. Finley Director, Regulatory Affairs 

EPA Response: Whether or not EPA takes any action on the listing of hydrogen sulfide as a 

hazardous air pollutant (HAP) is unrelated to EPA’s lifting of the stay of the EPCRA section 313 

reporting requirements for hydrogen sulfide. If any action is taken by EPA regarding the listing 

of hydrogen sulfide as a HAP, the commenter will have the opportunity to comment separately 

on any such action.
78

Commenter: Linda K. Phillips, Ph.D. [EPA-HQ-TRI-2009-0844-0092]

Linda Phillips 

<lindakp5@cox.net>

05/13/2010 02:58 AM

To Docket OEI@EPA

cc

bcc

Subject Docket ID No. EPA-HQ-TRI-2009-0844; FRL-9119-2

The website for submitting comments would not accept mine because it operates on Eastern 

Time. However, in California it is still May 12. I hope you'll accept my brief comment, attached 

in Word, and pasted below.

Linda Phillips

Re: Lifting of administrative stay of reporting of hydrogen sulfide under TRI Section 313

Docket ID No. EPA-HQ-TRI-2009-0844; FRL-9119-2

I have just learned of this proposal, and strongly support it. Because of the late date, these 

remarks will be brief. But I am stunned that for 15 years, H2S has not been reported under 

EPCRA - even though it is properly on the TRI lists as an Extremely Hazardous Substance 

(EHS). My understanding is that the administrative stay was due to an objection from the 

regulated community involving some the chronic toxicity of hydrogen sulfide. This issue should 

have been resolved long ago.

But a compelling reason for listing in Section 313 is the acute toxicity in a release. Hydrogen 

sulfide is unquestionably an acutely hazardous material, with the added danger of olfactory 

fatigue. At high concentrations, when it is most dangerous, its odor quickly becomes 

undetectable. The acute toxicity should have been sufficient to require that reporting 

requirements be reinstated.

Having served on the California Region I LEPC since 1987, and living in an area where oil and 

gas production frequently involves "sour gas" - for several years my home was downwind from 

such a facility - I feel very strongly that hydrogen sulfide should be reported under Section 313. 

Please lift the administrative stay. This action is long overdue.

Linda K. Phillips, Ph.D.

Santa Barbara, CA

EPA Response: EPA appreciates the commenter’s support of the lifting of the administrative 

stay of the EPCRA section 313 reporting requirements for hydrogen sulfide. 
79

Commenter: American Meat Institute [EPA-HQ-TRI-2009-0844-0093]

May 13, 2010

Administrator Lisa Jackson

U.S. Environmental Protection Agency

1200 Pennsylvania Avenue, N.W.

Washington, DC 20460

Re: American Meat Institute Comments on the “Hydrogen Sulfide; Community Right-toKnow Toxic Chemical Release Reporting,” Docket # EPA–HQ–TRI–2009–0844.

Dear Administrator Jackson:

The American Meat Institute (AMI) is pleased to submit these comments regarding the 

Environmental Protection Agency’s (EPA or the Agency) Hydrogen Sulfide; Community Rightto-Know Toxic Chemical Release Reporting published in the Federal Register on February 26, 

2010. AMI is the nation’s oldest and largest trade association representing packers and further 

processors of beef, pork, lamb, veal, turkey, and processed meat products. AMI represents a 

large number of meat packing and processing facilities nationwide. A number of these facilities 

have on-site rendering and wastewater treatment capabilities that may have fugitive releases of 

hydrogen sulfide. We are submitting these comments because EPA’s proposal to lift the 

administrative stay of the Emergency Planning and Community Right to Know Act (EPCRA) 

section 313 toxic chemical release reporting requirements for hydrogen sulfide will negatively 

affect our members.

The National Renderers Association also submitted comments on EPA’s proposed action, and 

AMI agrees with those comments. We emphasize the following mutual points of concern 

regarding EPA’s proposed action.

Hydrogen sulfide is a naturally occurring gas associated with the anaerobic bacterial decay of 

organic matter. In our members’ plants hydrogen sulfide is released primarily in rendering and 

waste treatment processes. The releases are fugitive, can be widespread and are in 

concentrations that are irregular and inconsistent. 

Nevertheless, to comply with EPCRA Section 313, our members will have to estimate their 

releases to determine if the reporting thresholds are met. Because of the ephemeral nature of the 

releases, however, standard field and even more sophisticated laboratory grade measurement 

devices are inadequate and unreliable. 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. Meat packing and processing plants do not have a 

reliable method for determining compliance. We, therefore, have significant concerns regarding 

how to implement EPCRA with respect to hydrogen sulfide and contend EPA should consider 

such practical issues before lifting the stay.

AMI appreciates the opportunity to provide these comments and would be pleased to discuss 
80

these matters with you further at your convenience.

Sincerely,

Ashley B. Peterson, Ph.D.

Director, Regulatory Affair

EPA Response: 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 (1). EPA has published 

emission factors for at least one stage of the rendering process (2). The commenter believes that 

reporting would be difficult for hydrogen sulfide, yet the National Renderers Association 

provided an estimate of 400 pounds of releases per year, thus it appears that these facilities could 

make at least a reasonable estimate of releases as required under EPCRA section 313. EPA 

notes that rendering plants as well as meat packing and processing plants must already report 

their release of ammonia, another gas that is also likely to have variations in production and 

release as it is also produced from the decay of organic matter. While EPA would like to collect 

the most accurate information possible, EPCRA section 313 only requires that facilities report a 

reasonable estimate of releases. EPA sees no reason why meat packing and processing plants 

should not be able to make at least reasonable estimates of the amounts of hydrogen sulfide 

manufactured and released. 

1. Emission Factor Documentation for AP-42 Section 9.5.3 Meat Rendering Plants Final Report. 

prepared by Midwest Research Institute (MRI) for the Office of Air Quality

Planning and Standards (OAQPS), U. S. Environmental Protection Agency (EPA), under EPA 

Contract No. 68-D2-0159. September 1995.

2. AP 42, Fifth Edition, January 1995. Compilation of Air Pollutant Emission Factors, Volume I: 

Stationary Point and Area Sources. Chapter 9: Food and Agricultural Industries section 9.5.3 

Meat Rendering Plants. Office of Air Quality Planning and Standards (OAQPS), Office of Air 

and Radiation, U. S. Environmental Protection Agency (EPA).

 
81

Commenters: Citizens for Environmental Justice, Community In-Powerment and 

Development Association, Northeast Ohio Gas Accountability Project, Sampson County 

Concerned Citizens For A Safe Environment, Air Alliance Houston, Cook Inletkeeper, 

Protect All Children’s Environment, Sustainable Energy & Economic Development 

Coalition, Texas Campaign for the Environment, Working Effectively for Clean Air Now, 

Downwinders at Risk, Person County People Rising In Defense of Ecology, Huron 

Environmental Activist League, Global Community Monitor, National Refinery Reform 

Campaign, National Bucket Brigade Coalition, Texas Oil and Gas Accountability Project, 

National Alliance for Drilling Reform, Wise County Alliance for Responsible Drilling, 

Groups Allied to Stop Pollution, OMB Watch, Sierra Club Lone Star Chapter, 

Environmental Integrity Project, Don’t Waste Arizona, EarthWorks, Oil & Gas 

Accountability Project, Citizens Against Environmental Destruction, Texas Environmental 

Justice Advocacy Services [EPA-HQ-TRI-2009-0844-0094]

May 12, 2010 

Administrator Lisa Jackson 

Office of Environmental Information Docket 

U.S. Environmental Protection Agency

Mail Code 2822T 

1200 Pennsylvania Avenue, N.W. 

Washington, D.C. 20460 

Hydrogen Sulfide: Community Right-to-Know Chemical Release Reporting 

Docket ID No. EPA-HQ-TRI--2009-0844 

Electronic: oei.docket@epa.gov

Dear Administrator Jackson: 

Petroleum refinery communities and communities with other industrial sites with toxic hydrogen 

sulfide (H2S) gas emissions across the country, including the heavily impacted communities of 

Port Arthur, Texas; Baton Rouge, Louisiana; and Wilmington, California strongly urge the 

Environmental Protection Agency (EPA) to lift the administrative stay (August 24, 1994) of the 

Emergency Planning and Community Right-to-Act (EPCRA) section 313 toxic chemical release 

reporting requirements and require the reporting of H2S in the annual Toxic Release Reporting 

(TRI) system (FR 75:38:8889-94, February 26, 2010). The EPA administrator needs to correct 

the egregious situation since 1994 of non-TRI reporting for the substance H2S because H2S is 

probably the most common toxic substance excluded from the TRI and is not listed in annual 

plant TRI reports for large industrial facilities that emit it every year into thousands of 

neighborhoods. The oil and gas industry has long opposed H2S reporting so as to attempt to 

deceive the public about the seriousness of H2S emissions from their industrial operations. 

Many of our residents and their children already are exposed to far more toxic H2S air pollution 

than they should be, and suffer from elevated rates of chronic respiratory effects, chronic 

neurotoxic effects, and other devastating adverse health effects as a result. Greatly exacerbating 

this problem are thousands of commercial and industrial facilities that release H2S gas —
82

including oil refineries, paper mills, carbon black plants, chemical plants, natural gas processing 

plants, crude oil pipelines, sewage treatment plants, and others — at facilities that operate right 

next to our homes, schools, daycare centers, playgrounds, clinics, hospitals, and churches.

H2S TRI reporting is a critical step toward documenting the seriousness of exposure to this 

highly toxic substance in impacted communities. A community group letter dated March 30, 

2009 was sent to the EPA administrator that documented that H2S is a highly toxic chemical yet 

under the Clean Air Act is an undesignated hazardous air pollutant under Section 112b. The 

March 30, 2009 letter, attached, supports the need for EPA to require the annual TRI reporting 

of H2S. This will help provide communities with more detailed information on the estimated 

gaseous emissions from local industrial facilities and help them seek lower H2S emissions and 

additional safety measures than currently exist. 

TRI reporting is critical to obtain better information on emissions and potential impacts. We 

assert that EPA must act to address adverse H2S impacts based on evidence of harmful 

exposures in numerous communities. H2S has toxicological effects at low concentrations and 

there is emerging evidence that H2S is a genotoxic agent, meaning it damages DNA. H2S is 

clearly an unreported toxic air pollutant and unlisted hazardous air pollutant (HAP). 

H2S, well known to cause death at high concentrations and respiratory-brain-nervous system 

effects at lower levels, also escaped addition to the original list of 188 HAPs in 1990 due to 

opposition from the oil and gas industry, despite the EPA’s attempts to include it. Back in 

January 1999, strong public support to add H2S to Title III of federally recognized air toxics 

occurred when 145 public health, environmental and community groups in 32 states sent a 

request to EPA based on scientific studies suggesting chronic, low-level exposures cause 

permanent damage to the brain and central nervous system. Indeed, new toxicological evidence 

reveals H2S can cause neuron death in the brain and serves as a solid regulatory basis that H2S is 

far worse than just a stinky chemical triggering bad headaches, nausea and discomfort at 

citizens’ home environment. The oil and gas industry has downplayed for decades the toxic 

effects of smelly H2S emissions when citizens have to breathe horrible, nauseating rotten egg 

odors. Industry officials allege it’s little more than a foul smelling odor with no harmful effects 

at sublethal low concentrations. Citizens who wrote to EPA in January 1999 and March 2009 

are still waiting for the agency to take action on this highly toxic substance. 

Hydrogen sulfide releases in 2008 reported to the National Response Center 

Every year the National Response Center (NRC) receives reports of toxic chemical spills and 

releases across the nation. Reports of H2S releases are included among the thousands filed with 

the NRC each year and are an indication of how widespread H2S releases are known to be. In 

2008 alone, industrial facilities reported H2S releases during 383 emergency events totaling an 

estimated 73,400 pounds and averaging nearly 200 pounds per event. The quantities of H2S 

released are primarily estimates of fugitive leaks from equipment failures and other process 

problems. Actual measurements are often lacking and the precise volumes of H2S released 

unavailable; therefore the actual releases of H2S may have been higher. Due to the health 

concerns about toxicity in the local communities, more precise monitoring of the H2S releases is 

needed at all industrial sites to provide more accurate data on the seriousness of H2S emissions. 
83

Oil refineries were responsible for the largest number of H2S gas emergency releases and the 

largest volume of H2S gas released in 2008. Oil refineries reported more than 330 (nearly 87%) 

H2S release incidents in the 2008 NRC report and refineries accounted for 65,978 pounds 

(nearly 90%) of H2S gas reportedly released to the NRC. Oil refineries reported H2S releases 

slightly higher on average (close to 200 pounds) than the other non-refinery sites. 

Miscellaneous facilities reported the remaining 10% in 53 incidents and a total of 7,422 pounds; 

these facilities had an average H2S release of 140 pounds or 30% less than the average refinery 

release at nearly 200 pounds. Oil and gas exploration and production facilities, which are 

known to release H2S at harmful levels, are not even included in these numbers because they are 

not required to report to the TRI. 

The 383 H2S emergency release events reported to the NRC in 2008 may only account for a 

fraction of the actual releases occurring. Thousands of non-reportable releases may occur each 

year if the H2S volume is less than the reportable minimum quantity, according to plant 

estimation methods and monitoring gaps, or if a facility is not aware of multiple small fugitive 

gas leaks occurring in their equipment and process units. Routine H2S fugitive equipment 

monitoring is not required. H2S is an extremely corrosive agent that aggressively attacks and 

eats through metal piping and crude oil tanks.

Gap in H2S TRI reporting from tens of thousands of Sour Oil and Gas Wells 

Tens of thousands of oil and gas wells in the U.S. contain noxious and lethal levels of H2S gas, 

but communities lack the right-to-know about the emissions from oil and gas wells. One 

concern about the TRI reporting system is a major gap that tens of thousands of sour (H2S) oil 

and gas wells throughout the nation are not required to submit TRI reports for their toxic 

environmental releases, including but not limited to H2S gas emissions. The EPA needs to 

address this TRI reporting gap and provide the public with more information on the toxic 

releases from oil and gas wells and related facilities that currently do not have to file reports. 

Sour oil and gas wells can release significant amounts of H2S gas into local communities and 

cause adverse health effects. While sour natural gas processing plants and related plants would 

have to report H2S TRI releases, sour oil and gas wells and thousands of small crude oil tanks 

will be exempted from submitting H2S TRI reports. Cumulatively, this could be a very large 

amount of H2S. 

The emissions of H2S gas poses a serious health issue for rural and urban residents living near oil 

and gas fields and better reporting would lead to acknowledging the need for solutions other than 

venting large volumes of sour gas with H2S in it. In 1992 while working as a regional 

investigator for the Texas Air Control Board (now part of Texas Commission on Environmental 

Quality), I investigated the air pollution complaint of a family complaining of constant sour gas 

emissions from several thousand oil wells operated by twelve major oil companies in the area of 

Forsan, Texas (immediately south of Big Spring in Howard County). Numerous H2S ambient air 

samples were collected along the state highway and other public areas. In nearly all cases, the 

samples were found to exceed the Texas state standard of 80 parts per billion averaged over 

thirty-minutes. Normally the state air agency did not investigate H2S emissions from sour oil 

wells, but in this instance with clear evidence of H2S levels exceeding the state standard in public 

areas and a family complaining of adverse health effects, the agency decided to issue violations 
84

to all twelve oil companies and require them to stop the venting of H2S gas at the wellheads. 

Each company developed a plan to quickly reduce the H2S venting. Within a matter of weeks, 

once the sour gas was collected from the oil wells and sent to a natural gas processing plant by 

pipeline for treatment (or temporarily flared), the H2S levels decreased sharply in the area to 

below the Texas ambient air quality standard. The complainant family reported that the H2S 

levels were barely noticeable and their two children no longer were experiencing serious 

headaches at home and on the way to school.

Estimates indicate that 15 to 25 percent of all natural gas wells in the U.S. may contain H2S.

In December, 2005, the Bureau of Land Management reported that there were more than 375 

reports of wells with H2S in the San Juan Basin of New Mexico and Colorado. Since then, 

many more wells have been drilled. 

A survey of accidental and Intentional H2S releases from natural gas wells and associate 

facilities causing evacuations and/or injury in Michigan’s Manistee and Mason Counties from 

1980 to 2002 found 70 H2S releases in only a 30-mile stretch of the Lake Michigan coast. 

Intentional and accidental releases in the Survey have led to emergency hospital treatment of 

more than 50 victims, including children, as well as numerous evacuations of business and 

residential areas exceeding 100 persons on one occasion. More have received emergency 

treatment at the scenes of exposure. Many others have refused medical treatment because they 

cannot afford hospital bills. Some victims have been forced to permanently abandon their 

homes and businesses. 

Environmental justice and hydrogen sulfide exposure: Petroleum refineries example 

We want to impress upon EPA its obligation to fully comply with and enforce Title VI of the 

Civil Rights Act of 1964, together with President Clinton’s February 11, 1994, Executive 

Order No. 12898 concerning the need for EPA to act on the environmental injustice in 

hundreds of communities impacted by H2S emissions. 

We urge EPA to seriously consider that the H2S exposures in affected communities near major 

oil refineries, as one example, often create a disproportionate air toxics burden for people of 

color and low-income populations. Residents in the neighborhoods close to one of the largest 

H2S industrial categories, the one hundred and forty oil refineries in the US, are often low 

income areas. A preliminary survey shows in leading petroleum refining areas in EPA regions 

(2, 3, 4, 5, 6, 9, 10), a majority of residents in the refinery neighborhoods are people of color.

Environmental justice is a grave need and major issue for dozens of oil refinery communities 

in Texas, Louisiana, California, Illinois, Pennsylvania, New Jersey, Indiana, Ohio, Kentucky, 

Alabama, Tennessee, Michigan, and Mississippi, which contain the bulk of the nation’s 

refineries, and where we stress that residents in refinery communities are disproportionately 

poor people of color. But besides the petroleum refining sector, several other industrial 

source categories are located in communities where people of color disproportionately reside.

An example of repeated serious H2S air pollution is a major Houston refinery reporting to the 

Texas Commission on Environmental Quality that it released over 1,700 pounds of H2S into the 

air during major upset incidents over several years, and the H2S releases are a key reason why 
85

local residents often complained about noxious rotten egg odors. Yet few H2S violations were 

issued by the state air pollution control agency and no nuisance odor conditions were confirmed 

by its investigators despite the exceptionally large releases of rotten egg gas and many public 

odor complaints. This Houston oil refinery reported H2S releases as low as 1 pound and up to 

235 pounds (#) including 18#, 20#, 27#, 37#, 68#, 74#, 155#, 159#, 235# and 305#. However, 

these H2S volumes were self-reported engineering estimates based on flare combustion 

efficiency calculations that assume 98% destruction was achieved and not based on actual H2S

monitoring. If refinery flares were not achieving 98% destruction which is highly likely, H2S

releases may have been significantly higher than the estimated 1,700 pounds.

EPA has recently acknowledged the need for improving flare combustion efficiency and the 

need for real-time emissions monitoring from flares, since no emissions monitoring system is 

currently required for refinery flares. Emergency flares are a huge community health concern 

since they routinely smoke badly for hours at a time, indicating combustion efficiency is not 

likely to be close to 98% destruction. 

Regulatory agencies, in some cases, tend to view residents living too close to industrial facilities 

as living in “industrial areas” where air pollution is bound to be a problem and suggest these 

people move away if they don’t like the poor air quality. Basically these “industrial areas” are 

sacrifice zones and regulatory agencies seem too often willing to ignore the outcry from residents 

in these “industrial areas” as not as important as the views of the industrial companies. 

U.S. oil refineries are importing sour crude oils with higher sulfur levels (andhigher H2S) than 

crude oils currently being used and a potential for worse H2S community impacts along pipeline 

routes and around the oil refineries. U.S. refineries have been seeking permit modifications at 

large plants to process higher sulfur crude oils from Venezuela, Mexico and now Canada 

(Alberta tar sands heavy crude oil). A powerful risk in higher sulfur in the Alberta tar sands 

heavy crude oil is an increased lethality hazard of higher H2S concentrations. Tar sands sulfur 

% is at least 4.4% and higher according to 2007 U.S. Geological Survey report (33) and it may 

contain 44,000 ppm of hydrogen sulfide when H2S is deadly at 500-900 ppm. Susceptible 

persons with vulnerable health conditions such as heart and/or lung ailments, including 

thousands of senior citizens, may die at only 50 ppm H2S levels, since lower H2S levels can 

more easily poison their comprised hearts and lungs. There is great concern for infants who 

may succumb at even lower H2S concentrations of 5-10 ppm exposures due to their uniquely 

vulnerable developing physiology, brain and nervous system. Higher sulfur crude oil is viewed 

by the oil industry as higher H2S concentrations to deal with and control. 

Three public health concerns result from higher H2S content in Canadian tar sands heavy 

crude oil 

1. Lethal hydrogen sulfide levels may reach 90 times over the minimum instant kill 

concentrations. H2S is extremely dangerous being instantly lethal at 0.050% -0.090% 

concentrations (500-900 ppm). Pipeline breaks and leaks of crude oil with higher H2S gas 

concentrations pose a significantly higher risk to public health and the environment compared to 

crude oil with lower sulfur and lower H2S gas levels. 
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2. Increased chronic hydrogen sulfide exposure potential in affected communities. Pipelines and 

refineries handling higher sulfur crude with more H2S will mean more serious community 

exposures to sublethal concentrations and related health effects. 

3. Corrosive acid gas. H2S is extremely corrosive and causes steel to experience sulfide stress 

cracking (SCC). H2S is called an “acid gas” because it’s extremely acidic and eats through solid 

steel leaving holes in tanks, pipes and processing equipment. The extreme corrosivity of higher 

H2S in the Canadian tar sands heavy crude oil increases the potential for serious leaks and 

accidents from pipelines and increases the health hazards if accidental leaks occur. The presence 

of H2S, a corrosive material, is of particular concern when it is also in the presence of other 

corrosive agents such as CO2 +water, chlorides—which cause chloride stress cracking (CSC), 

and oxygen (O2) which causes rusting of steels and other materials. Such combination requires 

particular care in the selection of materials to resist such combined corrosion and adequately 

contain the H2S. 

EPA needs an accurate national emissions inventory (EI) for hydrogen sulfide gas

The EPA Office of Air Quality Planning & Standards has estimated H2S national emissions at 

more than 56,700 tons, but does not include sources such as CAFOs, municipal waste landfills, 

and sugar beet manufacturing. EPA needs a more accurate national EI for hydrogen sulfide gas 

from major industrial facilities, minor sources and exempted sources such as oil & gas wells.

The national number of sites with H2S will be enormous since oil & gas wells number in the tens 

of thousands alone. The California Air Resources Board provided a 1999 EI for H2S in 

California of 5,688,172 pounds, an indication of the large-scale H2S volume. 

(http://www.oehha.org/air/chronic_rels/pdf/7783064.pdf) 

Nearly 200 Texas major industrial plants estimated H2S releases at 7,187,988.4 pounds (3,594 

tons) in 1997, according to state EI records at the Texas Commission on Environmental 

Quality, not including landfills, CAFOs, oil & gas wells, small crude oil storage tanks, and 

many other minor facilities. That added 3,594 tons (3.3%) to the ~108,000 tons of air toxics 

emitted by Texas plants in 1997. Despite the need for a better national emissions inventory of 

H2S from potential sources, the EPA recognizes that H2S is a poorly regulated air pollutant 

with significant nationwide emissions estimated at more than 110 millions pounds annually. It 

is certainly ranks among the worst regulated air toxics. 

Conclusion 

Public health scientists have recognized for over a decade that hydrogen sulfide is a potent 

neurotoxin, and chronic exposure to low ambient levels causes irreversible damage to the brain 

and central nervous system. Ultra-low levels of H2S down to 25 ppb have been associated with 

acute exposure causing eye irritation in community settings in the United States, Europe and 

New Zealand. Now emerging scientific evidence supports H2S as a cause of neuron death, 

confirming findings by Kaye Kilburn of irreversible brain damage. The latest scientific findings 

suggests H2S causes DNA damage as a genotoxic agent, which EPA can no longer ignore. The 

potential carcinogenic implications of H2S demand that EPA act to protect public health. 
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Children are among the most susceptible to this poison gas, and EPA needs to do a more 

effective job of protecting schoolchildren from H2S impacts. Today, it is unacceptable for 

communities to have to continue suffering the ill effects of H2S when the technology to monitor 

and control H2S emissions exists. As EPA has learned in the last four decades, environmental 

injustice is a significant fact of life for thousands of communities in this nation and these 

residents all have a right to clean, safe air. 

EPA needs to require annual reporting of H2S as a toxic substance under the Toxic Release 

Inventory (TRI) reporting program, since H2S is not reported due to an administrative stay 

issued August 22, 1994 evidently under a legal threat by the American Petroleum Institute. It’s 

extraordinary that industry has delayed reporting of H2S for twenty years. EPA needs a TRI 

reporting threshold of 1.0 pound for H2S, not 10,000 pounds as was originally the requirement. 

We request that EPA immediately lift the administrative stay on H2S and require TRI reporting 

in the next TRI submission cycle. The TRI data would also help EPA compile more accurate 

H2S data and help EPA decide how best to regulate and reduce H2S emissions.

Respectfully yours,

Neil J. Carman, Ph.D.

Sierra Club’s Clean Air Team and the Lone Star Chapter of the Sierra Club

Former regional investigator with Texas Commission on Environmental Quality

1202 San Antonio street Austin, Texas 78701 Tel 512-472-1767 

Suzie Canales Citizens for Environmental Justice Corpus Christi, Texas 

Eric Schaeffer Environmental Integrity Project Washington, D.C. 

Matthew Tejada, Ph.D. Houston Air Alliance Houston, Texas 

Becky Bornhorst Downwinders At Risk Midlothian, Texas 

Mike Eisenfeld San Juan Citizens Alliance Farmington, New Mexico 

Jaime Chimner Citizens Against Environmental Destruction Northern Michigan 

Steve Brittle Don’t Waste Arizona Phoenix, Arizona 

Bob Shavelson Cook Inletkeeper Homer, Alaska 

Shirley J. McNall Impacted citizen Aztec, New Mexico 

Tammy Cromer Campbell Working Effectively for Clean Air Now Longview, Texas 

Pat Hill Person County People Rising In Defense of Ecology North Carolina 

Sharon Hill Texas Oil and Gas Accountability Project Dish, Texas 

Sharon Wilson National Alliance for Drilling Reform, and Wise County Alliance for 

Responsible Drilling Decatur, TX Hilton Kelly Community In-Powerment and Development 

Association Port Arthur, Texas 

Gwen Lachelt EARTHWORKS’, and Oil & Gas Accountability Project, Durango, Colorado 

Denny Larson Global Community Monitor, National Refinery Reform Campaign & National 

Bucket Brigade Coalition Oakland, California 

Lorrie Cotterill Groups Allied to Stop Pollution Wilmer, Texas 

Karen Hadden Sustainable Energy & Economic Development Coalition Austin, Texas 

Kari Matsko Northeast Ohio Gas Accountability Project Mentor, Ohio 

Bill Freese Huron Environmental Activist League Alpena, Michigan 

E.M.T. O’NanProtect All Children’s Environment Marion, North Carolina 
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Areatha Troublefield Sampson County Concerned Citizens for a Safe Environment North 

Carolina 

Robin Schneider Texas Campaign for the Environment Austin, Texas 

Brian Turnbaugh OMB Watch Washington, D.C. 

Juan Parras Texas Environmental Justice Advocacy Services Houston, Texas 

 

EPA Response: EPA appreciates the commenter’s support of the lifting of the administrative 

stay of the EPCRA section 313 reporting requirements for hydrogen sulfide. 

With regard to the comments about adding industrial sectors such as oil and gas wells and 

related facilities that currently do not have to file reports under EPCRA section 313, EPA is 

currently evaluating additional industry sectors for possible addition. 

Concerning environmental justice issues, while not a statutory criteria for listing a 

chemical under EPCRA section 313, they can be an important consideration. By lifting the stay 

of the EPCRA section 313 reporting requirements for hydrogen sulfide, EPA would be providing 

communities across the United States (including minority populations and low income 

populations) with access to data which they may use to seek lower exposures and consequently 

reductions in chemical risks for themselves and their children. This information can also be used 

by government agencies and others to identify potential problems, set priorities, and take 

appropriate steps to reduce any potential risks to human health and the environment. Therefore, 

the informational benefits of lifting the stay will have a positive impact on the human health and 

environmental impacts of minority populations, low-income populations, and children.

Regarding the commenter’s suggestion that EPA should lower the EPCRA section 313 

reporting threshold for hydrogen sulfide to 1 pound, the commenter did not provide a basis for 

such a threshold change. EPA is not aware of any particular reason that the reporting threshold 

for hydrogen sulfide should be lowered and thus has no plans at this time to address the issue.