Sulfur Case 0031 Docket Number EPA-HQ-OPP-2008-0176 Interim Registration Review Decision

www.regulations.gov Pesticide Re-evaluation Division

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Table of Contents

I. INTRODUCTION............................................................................................................. 3

II. RESPONSE TO COMMENTS........................................................................................ 6

III. SCIENTIFIC ASSESSMENTS ..................................................................................... 10

IV. INTERIM REGISTRATION REVIEW DECISION.................................................. 10

Appendix A: Listed Non-Target Species Subject to Section 7 Consultation with Fish and 

Wildlife Service ........................................................................................................................... 16

Appendix B: Listed Non-Target Species with Changes to EPA Effect Determinations from 

the June 28, 2013 Revised Gas Cartridge Ecological Risk Assessment ................................. 18

Appendix C: Gas Cartridge Label Table for All Gas Cartridge Products ........................... 20

Appendix D: Geographic Ranges Maps for Species with Planned Bulletins ........................ 21
Sulfur Case 0031 Docket Number EPA-HQ-OPP-2008-0176 Interim Registration Review Decision

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I. INTRODUCTION

This document is the Environmental Protection Agency’s (EPA or the Agency) Interim

Registration Review Decision for Sulfur and is being issued pursuant to 40 CFR sections 155.56 

and 155.58. A registration review decision is the Agency's determination whether a pesticide 

meets, or does not meet, the standard for registration in the Federal Insecticide, Fungicide, and 

Rodenticide Act (FIFRA). The Agency may issue, when it determines it to be appropriate, an 

interim registration review decision before completing a registration review. Among other 

things, the interim registration review decision may (1) require new risk mitigation measures; 

(2) impose interim risk mitigation measures; (3) identify data or information required to 

complete the review; and (4) include schedules for submitting the required data, conducting new 

risk assessments and completing the registration review.

FIFRA, as amended by the Food Quality Protection Act (FQPA) of 1996, mandated the 

continuous review of existing pesticides. All pesticides distributed or sold in the United States 

generally must be registered by the EPA based on scientific data showing that they will not cause 

unreasonable risks to human health or to the environment when used as directed on product 

labeling. The registration review program is intended to make sure that, as the ability to assess 

and reduce risk evolves and as policies and practices change, all registered pesticides continue to 

meet the statutory standard of no unreasonable adverse effects. Changes in science, public 

policy, and pesticide use practices will occur over time. Through the registration review 

program, the Agency periodically reevaluates pesticides to make sure that as these changes

occur, products in the marketplace can continue to be used safely. Information on this program is 

provided at www.epa.gov/oppsrrd1/registration_review/.

In 2006, the Agency implemented the registration review program pursuant to FIFRA 

section 3(g) and will review each registered pesticide every 15 years to determine whether it 

continues to meet the FIFRA standard for registration. 

Pursuant to 40 CFR §155.50, the Agency formally initiated registration review for sulfur 

(Case 0031). The Agency’s registration review of sulfur (Case 0031) includes all pesticidal uses 

of sulfur which include agricultural as well as gas cartridge uses. Gas cartridge products that

contain sulfur may also contain carbon and sodium or potassium nitrate. Sodium and potassium 

nitrate (Case 4052) and carbon and carbon dioxide (Case 4019) are also undergoing registration 

review. Consequently, there are several common support documents and regulatory conclusions 

shared among these cases. Furthermore, the registration review interim decisions for all 

compounds with gas cartridge uses are being made available simultaneously.

Sulfur has been used as a pesticide in the United States since the 1920s. A Reregistration 

Eligibility Decision (RED) was signed in 1991. Sulfur is currently registered for use as an 

insecticide, acaricide and fungicide on a wide range of field and greenhouse-grown food and 

feed crops, livestock (and livestock quarters; ex. horse, dairy cattle, goats, poultry, and sheep 

spray), and indoor and outdoor residential sites (ex. dog spray). Use sites include tree fruit, nuts,

berries, vegetables, root crops, field crops, pets (dogs), ornamentals, and turf (including 

residential lawns and golf courses). Formulations include dust, water dispersible granules or dry 

flowable, emulsifiable concentrate, flowable concentrate, liquid, liquid ready-to-use, wettable 
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powder, and wettable powder/dust and may be applied by chemigation, soil band treatment 

(ground sprayer, aircraft), soil treatment (soil incorporation treatment), low volume spray 

concentrate (low volume ground concentrate), high volume dilute spray (high volume ground 

sprayer), or dust (ground or aircraft). Products containing elemental sulfur are registered for use 

on crops at relatively high rates up to 122.5 lb a.i./A per application, but can also be used as a 

soil amendment (non-pesticidal use) to increase fertility and/or reduce the pH of highly alkaline 

soils at much higher rates (up to approximately 3,300 lb a.i./A for highly alkaline clay soils that 

need extensive acidification, Mullen et al. 20071).

In addition to the uses listed above, sulfur is also registered for use in gas cartridge 

products. Gas cartridges are registered for outdoor use to control burrowing mammals (EPA Reg. 

Nos. 4-463, 73342-8, 9086-4, 10551-1, and 56228-2) and relatively large mammals in dens (EPA 

Reg. No. 56228-21). A list of existing gas cartridge products and their target pests is provided in

the table below. To use the products, the user lights the fuse, places the cartridge in the burrow or 

den and seals all known exits/entrances. Animals within the burrow or den are asphyxiated by 

the release of carbon dioxide and other toxic gases. 

EPA Registration 

Number

Product Name Registrant Target Species

4-463 Smoke'em Bonide Products, 

Inc

Woodchucks, gophers

73342-8 Amdro Gopher Gasser Ambrands Gophers, ground 

squirrels

9086-4 Revenge Rodent Smoke 

Bomb

Roxide 

International, Inc.

Gophers, woodchucks

10551-1 The Giant Destroyer Atlas Chemical 

Corporation

Moles, gophers, 

woodchucks, Norway 

rats, ground squirrels, 

skunks

56228-2 Gas Cartridge U.S. Department of 

Agriculture

Woodchucks, yellowbellied marmots, 

ground squirrels, prairie 

dogs

56228-21 Large Gas Cartridge U.S. Department of 

Agriculture

Coyotes, red foxes, 

striped skunks

 

1 Mullen, R., Lentz, E. and M. Watson. 2007. The Ohio State University Extension Fact Sheet (Soil Acidification: 

How to lower the soil pH, by R. Mullen, E. Lentz, and M. Watson, AGF-507-07, dated 2007)
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The following timeline highlights significant events that have occurred during the 

registration review of sulfur and can be found in the public docket (EPA-HQ-OPP-2008-0176):

 March 26, 2008 – The Agency published the Sulfur Registration Review Summary 

Document, dated March 19, 2008 in docket number EPA-HQ-OPP-2008-0176 for a 90-

day public comment period. The Summary Document included the Agency’s Preliminary 

Work Plan for Sulfur, a Sulfur Fact Sheet, the Problem Formulation for Ecological Risk 

Assessment for Sulfur, dated February 7, 2008, the Problem Formulation for Ecological 

Risk Assessment, for Carbon Dioxide and Gas Fumigant Producing Cartridges: Carbon, 

Sawdust, Sodium Nitrate, Potassium Nitrate, and Sulfur, dated March 17, 2008 and the 

Sulfur Human Health Risk Scoping Document in Support of Registration Review, dated

January 17, 2008. The Agency received one comment concerning the Sulfur Summary 

Document. The comment did not change the work plan for the registration review of 

sulfur.

 September 4, 2008 – The Agency published the Sulfur Final Work Plan, dated August 

15, 2008 which stated that the Agency would conduct a comprehensive ecological risk 

assessment that included an endangered species risk assessment, and that EPA would 

conduct new occupational and residential exposure risk assessments for registration 

review. The Sulfur Final Work Plan also stated that the Agency then anticipated requiring

a subchronic inhalation study for use in quantitatively assessing risk to handlers. 

 February 18, 2009 – The Agency published Sulfur. Human Health Risk Scoping 

Document in Support of Registration Review – Addendum, dated January 29, 2009. This 

addendum explained why the subchronic inhalation study for sulfur would no longer be 

required.

 April 8, 2010 – The Agency initiated informal consultation under the Endangered Species 

Act (ESA) section 7(a)(2) with the U.S. Fish and Wildlife Service (FWS) for the gas 

cartridge uses of sulfur, carbon and inorganic nitrate.

 May 26, 2010 – The Agency published the draft Registration Review Ecological Risk 

Assessment and Effects Determinations, Carbon, Carbon Dioxide, Sawdust, Sodium 

Nitrate, Potassium Nitrate and Sulfur Gas Cartridges, dated March 30, 2010 for a 60-day 

public comment period. During that time, one comment was received from U.S. Fish and 

Wildlife Service (FWS) Region 4. EPA made a “May Affect and Likely to Adversely 

Affect (LAA)” determination for federally listed terrestrial mammals, terrestrial birds, 

and terrestrial invertebrates and a likely to modify determination for designated critical 

habitats. EPA also concluded “No Effect” for aquatic species given the expected lack of 

exposure to non-target taxa (EPA-HQ-OPP-2008-0176; FRL–8826–6). 

 December 17, 2010 – The Agency published the EFED Response to Comments for 

Registration Review for Carbon, Nitrates, and Sulfur Gas Cartridges, dated October 20, 

2010 and Input for Mitigation Options for Endangered and Threatened Species Identified 

in EFED’s Carbon, Nitrates, and Sulfur Gas Cartridges Registration Review Ecological 
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Risk Assessment and Effects Determination, dated November 16, 2010. This document 

responded to comments received concerning the draft ecological risk assessment.

 July 16, 2012 – The Agency provided an Addendum to The Environmental Fate And 

Ecological Risk Assessment For Carbon Dioxide And For Carbon, Sawdust, Sodium 

Nitrate, Potassium Nitrate And Sulfur Containing Cartridges. This document updated 

EPA’s list of threatened and endangered species with “LAA” determinations as a result 

of direct effects from gas cartridge use. The document also outlined potential mitigation 

that, if adopted by the registrants, would result in changing the determination to “No 

Effect” for certain species.

 June 26, 2013 – The Agency published draft human health and ecological risk 

assessments for uses of sulfur other than gas cartridges: Sulfur. Summary of Human 

Health Risk Assessments to Support Registration Review, dated May 1, 2013, and Sulfur 

Environmental Fate and Ecological Preliminary Risk Assessment, dated May 29, 2013. 

During the 60 day comment period for these draft risk assessments, one comment was 

received. The comment did not challenge or impact the conclusions of the draft risk 

assessments.

 June 28, 2013 – The Agency finalized the Revision to the environmental fate and 

ecological risk assessment for carbon dioxide and for carbon, sawdust, sodium nitrate, 

potassium nitrate and sulfur containing cartridges. This document provides an updated 

list of potentially affected species and additional mitigation options.

 June 2014 – The Agency published the Sulfur Proposed Interim Registration Review 

Decision, dated May 28, 2014 in docket number EPA-HQ-OPP-2008-0176 for a 60-day 

public comment period. Comments were received from the Center for Biological 

Diversity, Defenders of Wildlife, the California Department of Pesticide Regulation, the 

USDA Animal and Plant Health Inspection Service (APHIS), and the Agricultural 

Commissioner of San Luis Obispo County, California.

 October 2015 – The Agency is publishing the Sulfur Interim Registration Review 

Decision and the Response to Public Comments on the Registration Review Proposed 

Interim Decisions for Gas Cartridges

For further information on sulfur, additional documents can be found in EPA’s public 

docket (EPA-HQ-OPP-2008-0176) at www.regulations.gov. 

II. RESPONSE TO COMMENTS

Below is a summary of the primary comments and Agency responses on the Proposed 

Interim Registration Review Decision for sulfur. A more detailed summary of comments on the 

Proposed Interim Registration Review Decision for sulfur and the Agency’s response can be 

found in the Response to Public Comments on the Registration Review Proposed Interim 

Decisions for Gas Cartridge in EPA’s public docket for sulfur (EPA-HQ-OPP-2008-0176) at 

www.regulations.gov.
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In the Proposed Interim Registration Review Decision for sulfur, the Agency proposed 

the use of the Bulletins Live!2internet application for endangered species risk mitigation for gas 

cartridges, which would have resulted in the Agency making a “No Effect” determination on 11 

listed species by prohibiting the use of all gas cartridges within the geographic range of the 

following species:

1. Carolina northern flying squirrel

2. Coachella Valley fringe-toed lizard

3. Desert slender salamander

4. Gopher tortoise

5. Hualapai Mexican vole

6. Morro Bay kangaroo rat

7. Mount Graham red squirrel

8. San Miguel Island fox

9. Santa Cruz Island fox

10. Santa Rosa Island fox

11. Utah prairie dog

The Agency had also proposed to work with USDA/APHIS to split their gas cartridge 

registrations into separate sub-labels. One sub-label would be for USDA/APHIS Wildlife 

Services use only, and would not restrict use to target species only. The other sub-label would be 

for consumer use and would restrict use to target species only.

The comments received by the Center for Biological Diversity and Defenders of Wildlife 

did not result in any changes to the proposed mitigation. However, the comments received by the 

California Department of Pesticide Regulation (CDPR), the Agricultural Commissioner of San 

Luis Obispo County, California, and the USDA Animal and Plant Health Inspection Service 

(APHIS) did result in changes to the proposed mitigation. Based on the public comments which 

are described in further detail below, EPA has decided to issue Bulletins on 4 of the 11 species 

that were proposed: the gopher tortoise, Hualapai Mexican vole, Mount. Graham red squirrel,

and Utah prairie dog. With the exception of the Utah prairie dog, the Bulletins will prohibit use 

of all gas cartridge products within the geographic range of the species. For the Utah prairie dog, 

the Bulletins will prohibit use of certain gas cartridge products within the geographic range of 

the species. There will not be a Bulletin prohibiting use of the USDA/APHIS Large Gas 

Cartridge product (EPA Reg No. 56228-21) in the geographic range of the Utah prairie dog. 

Additionally, the Agency will work with USDA/APHIS to pursue separate registrations for gas 

cartridge products that may be used in areas prohibited by Bulletins if certain conditions are met. 

Below is a summary and brief discussion of the primary comments and Agency responses.

CDPR and the San Luis Obispo County Agricultural Commissioner commented that for 

many of the listed species identified in the assessment to be at risk in California, protective 

measures are currently in place. Similar to Bulletins Live!, California noted that it has employed

 

2 When the Proposed Interim Registration Review Decision for sulfur was issued, the first version of Bulletins 

Live! was available. However, an updated version, Bulletins Live! Two, is now available at 

http://www.epa.gov/espp/bulletins.htm.
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a publicly accessible web-based tool (PRESCRIBE3) to provide pesticide specific use limitations 

intended to protect listed species. It is important to note, however, that in general, the pesticide 

use limitations provided in PRESCRIBE are voluntary measures. Also, the mitigation suggested 

in PRESCRIBE differs from what the Agency had proposed in that it recommends that “qualified 

individuals” who have been trained to distinguish dens and burrows of target species from those 

of nontarget species make the cartridge applications in listed species’ range. The Agency, on the 

other hand, had proposed that cartridge use be prohibited within the geographic range of the six 

listed species provided below. By prohibiting use in those ranges, the Agency would have been 

able to make a No Effect determination for these six listed species.

1. Morro Bay kangaroo rat

2. Coachella Valley fringe-toed lizard

3. Desert slender salamander

4. Santa Rosa Island fox

5. San Miguel Island fox

6. Santa Cruz Island fox

The Agency reviewed the existing protection measures in PRESCRIBE and considered 

incorporating these measures into the Agency’s Bulletins Live! approach. Based on discussions 

with CDPR, the PRECRIBE measures for gas cartridges were based on an existing 1996 

consultation where FWS concurred with CDPR’s “Not Likely to Adversely Affect (NLAA)” 

determination. However, the U.S. Fish and Wildlife Service (FWS) informed EPA and CDPR 

that consultation would need to be re-initiated to determine whether the existing PRESCRIBE 

measures based on the 1996 concurrence are still protective of the listed species of concern. In 

addition, FWS indicated that a number of species have been listed since the 1996 concurrence, 

and that these species would also need to be considered as part of the consultation re-initiation. 

Therefore, EPA will not issue endangered species protection Bulletins for listed species in 

California prior to formal Section 7 Endangered Species consultation with FWS. 

USDA/APHIS also submitted a number of substantive comments to the Agency. Based 

upon several discussions with USDA/APHIS in August and September 2015, the Agency will 

work with USDA/APHIS to pursue separate registrations for gas cartridge products that may be 

used in areas prohibited by Bulletins if:

 The products are only used by USDA/APHIS personnel, and

 USDA/APHIS has completed Section 7 consultations with the FWS on the use of these 

products within the specified area and follows all FWS specifications for use.

On a September 1, 2015 conference call, USDA/APHIS indicated that they do not believe 

their large gas cartridge product (Reg No. 56228-21) poses a risk to the Utah prairie dog because 

the dens or burrows of the target pests for that product would not likely provide habitat for the 

prairie dog. Therefore, they did not agree to a Bulletin prohibiting use of the large gas cartridge 

in the range of the Utah prairie dog. However, EPA concluded in its 2013 revised risk 

assessment that exposure to the small and large gas cartridges is likely to adversely affect (LAA) 

 

3

http://www.cdpr.ca.gov/docs/endspec/prescint.htm
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the Utah prairie dog. Therefore, the Agency has decided to issue Bulletins for the Utah prairie 

dog only for the small gas cartridge products (Reg. No. 9086-4, 73342-8, 4-463, 10551-1, and 

56228-2) and to formally consult with FWS on the risk of the large gas cartridge to the Utah 

prairie dog.

USDA/APHIS also commented on the use prohibitions in the geographic range of the 

Carolina northern flying squirrel and other species that the Agency had, at the time of the 

Proposed Interim Registration Review Decision for sulfur, determined to be entirely within the 

boundaries of federal lands. USDA/APHIS declined to agree to those use prohibitions because 

the resolution of the geographic range maps provided by the Agency did not allow 

USDA/APHIS to determine whether or not the habitat delineations were in agreement with 

boundaries of Federal lands. Upon further Agency review of the range for the Carolina northern 

flying squirrel, only 79% of the species range occurs within Federal land boundaries. As a result, 

the Agency is no longer proposing Bulletins for this species prior to formal consultation. 

USDA/APHIS had also requested further detail on the sub-labeling approach that was 

proposed for their gas cartridge registrations. However, after the Proposed Interim Registration 

Review Decision was published, the Agency discussed the feasibility of the sub-label approach 

with State Lead Agencies that handle pesticide registration and enforcement, and it was 

determined that the sub-label approach would be difficult for the states to enforce. Instead, 

USDA has agreed to split the APHIS and consumer uses into their own separate registrations.

Details on this approach are outlined below in the Endangered Species Risk Mitigation 

Measures.

As a result of the comments from USDA/APHIS, the Agency will not issue endangered 

species protection Bulletins for the following listed species prior to formal Section 7 Endangered 

Species consultation with the FWS:

1. Carolina northern flying squirrel

2. Utah prairie dog, for USDA/APHIS large gas cartridge, EPA Reg. No. 56228-21

In summary, as a result of public comments received on the Proposed Interim 

Registration Review Decision, the Agency can no longer make a “No Effect” determination, for 

all gas cartridge sizes, on the 8 species listed above (6 species as a result of comments from 

California and 2 species as a result of comments from USDA/APHIS) and will proceed with 

formal Section 7 Endangered Species consultation with the FWS for these and all the other listed 

species determined to have a potential direct or indirect risk from gas cartridge use. See 

Appendix A for the full list of direct effect species that will require consultation.

The Agency is making a “No Effect” determination, and will issue endangered species 

protection Bulletins for the: gopher tortoise, Hualapai Mexican vole, Mount Graham red squirrel,

and the Utah prairie dog (for all gas cartridge products except for USDA/APHIS large gas 

cartridge, EPA Reg. No. 56228-21). The Agency will proceed with formal Section 7 consultation 

with the FWS on the Utah prairie dog for the USDA/APHIS’ large gas cartridge, as described 

above.
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III. SCIENTIFIC ASSESSMENTS

For a full description of the Agency’s ecological and human health risk assessments, as 

well as a benefits assessment, please refer to the Proposed Interim Registration Review Decision 

for sulfur, which can be found in EPA’s public docket (EPA-HQ-OPP-2008-0176) at 

www.regulations.gov.

IV. INTERIM REGISTRATION REVIEW DECISION

In accordance with 40 CFR Sections 155.56 and 155.58, the Agency is issuing this 

Interim Registration Review Decision. Except for the EDSP and ESA components of this case, 

the Agency has made the following interim registration review decision: (1) no additional data 

are required at this time; and (2) changes to the affected registrations and their labeling are 

needed at this time.

In this Interim Registration Review Decision, EPA is making no human health or 

environmental safety findings associated with the EDSP screening of sulfur, nor is it making a 

complete endangered species finding. The Agency’s final registration review decision for sulfur

will depend upon both the result of the completion of an ESA Section 7 consultation with FWS, 

and an EDSP FFDCA section 408(p) determination. 

A. Human Health Risk

Based on the human health risk assessment conducted in support of the Registration 

Review for sulfur, the Agency determined that there are no human health risks of concern for the 

currently registered uses of sulfur. 

B. Ecological Risk

Conventional uses

Based on low toxicity of sulfur to aquatic organisms and terrestrial vertebrates, the lack 

of ecological incidents for these taxa, and the rapid incorporation of elemental sulfur into the 

natural sulfur cycle once released, the Agency has determined that there are no potential risks to 

listed and non-listed aquatic organisms and terrestrial vertebrates, and has therefore made a No 

Effect determination on listed aquatic organisms and listed terrestrial vertebrates.

EPA has determined that there is potential for adverse effects to some non-target 

terrestrial invertebrate and terrestrial plant species. For example, the potential for terrestrial plant 

exposure exists from off-site transport via the various application methods and high application 

rates of sulfur. However, given the long use history, the lack of incidents since 2001 and that the 

three of five incidents taken from 1999-2001 include other pesticides while the two remaining 

incidents are not associated with a high degree of certainty for sulfur – as well as the fact that 

sulfur is quickly incorporated into the sulfur cycle upon contact with water or soil, the Agency 

considers these risks to non-listed terrestrial invertebrates and plants to be low. To evaluate the 

potential risk of sulfur to listed terrestrial invertebrates and terrestrial plants, the Agency will 
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take the approach outlined below, which is different than the endangered species risk assessment 

approach that was taken for the gas cartridge uses of sulfur. Because exposure to the gases 

released by cartridges are limited to organisms within burrows/dens, the Agency was able to 

make clear effects determinations; however, for the non-gas cartridge uses of sulfur, the Agency 

used a method similar to what has been done for other Registration Review chemicals, where a 

“No Effect” determination is made when possible. For species where the Agency cannot

conclude “No Effect,” the Agency is deferring a full endangered species determination until the 

new methods being developed based on the NAS report recommendations are vetted and 

implemented.

Consistent with EPA’s responsibility under the Endangered Species Act (ESA), the 

Agency will evaluate risks to federally listed threatened and endangered (listed) species from 

registered uses of pesticides in accordance with the Joint Interim Approaches developed to 

implement the recommendations of the April 2013 National Academy of Sciences (NAS) report, 

Assessing Risks to Endangered and Threatened Species from Pesticides. The NAS report 

outlines recommendations on specific scientific and technical issues related to the development 

of pesticide risk assessments that EPA and the Services must conduct in connection with their 

obligations under the ESA and FIFRA. 

In November 2013, EPA, FWS, National Marine Fisheries (the Services), and the U.S. 

Department of Agriculture released a white paper containing a summary of their joint Interim 

Approaches for assessing risks to listed species from pesticides. These Interim Approaches were 

developed jointly by the agencies in response to the NAS recommendations, and reflect a 

common approach to risk assessment shared by the agencies as a way of addressing scientific 

differences between the EPA and the Services. Details of the joint Interim Approaches are 

contained in the November 1, 2013 white paper, Interim Approaches for National-Level 

Pesticide Endangered Species Act Assessments Based on the Recommendations of the National 

Academy of Sciences April 2013 Report.4 

Given that the agencies are continuing to develop and work toward implementation of the 

Interim Approaches to assess the potential risks of pesticides to listed species and their 

designated critical habitat, the ecological risk assessment supporting this Interim Registration 

Review Decision for sulfur does not contain a complete ESA analysis, including effects 

determinations for specific listed terrestrial invertebrate or terrestrial plant species or designated 

critical habitat that may be exposed to non-gas cartridge uses of sulfur. While the agencies 

continue to develop a common method for ESA analysis, the preliminary risk assessment for the 

registration review of sulfur describes the level of ESA analysis completed for this particular 

registration review case. This assessment will allow EPA to focus its future evaluations on the 

types of species where the potential for effects exists, once the scientific methods being 

developed by the agencies have been fully vetted. Once the agencies have fully developed and 

implemented the scientific methods necessary to complete risk assessments for listed species and 

their designated critical habitats, these methods will be applied to subsequent analyses of sulfur

as part of completing this registration review.

 

4 http://www.epa.gov/espp/2013/interagency.pdf
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Gas cartridge uses

EPA has determined that there is potential for adverse effects to non-target, non-listed 

terrestrial animals that inhabit burrows or dens. However, adverse effects to non-listed terrestrial 

animals from the application of the gas cartridges are localized to the application site. In 

addition, all gas cartridge product labels include the statement, “Check all burrows for signs of 

non-target species. If present, do not treat burrows.” This statement limits the potential for 

exposure. The combination of the localization of adverse impacts, as well as the protective label 

language for non-target species leads EPA to conclude that exposure to non-target, non-listed 

terrestrial animals is expected to impact only a small number of non-target organisms, if any. For 

the ecological risk assessment, the Agency reviewed available ecological incident data and found 

that there were no reported ecological incidents attributed to gas cartridge use. 

In the Proposed Interim Registration Review Decision for sulfur, it was explained that 

EPA had determined that the use of gas cartridge products containing potassium and sodium 

nitrate, carbon and carbon dioxide, and in some gas cartridge products, sulfur, is LAA 56 listed 

species. Under the ESA, an action is determined to be LAA if a single individual of a listed 

species is likely to be adversely affected. 

Through the risk mitigation measures described below, the Agency will be able to change 

the LAA determination to “No Effect” for a number of species. 

Given the risks and benefits of sulfur use, which were summarized in the Proposed 

Interim Decision for sulfur, the Agency concludes that conventional and gas cartridge uses of 

sulfur will not pose unreasonable risk to non-target terrestrial invertebrate and terrestrial plant 

species. No mitigation measures are required to address risk to non-target non-listed species.

However, to address risk to threatened and endangered species, the gas cartridge registrants have

agreed to the mitigation measures described below.

Endangered Species Risk Mitigation Measures

In developing the Proposed Interim Registration Review Decision, the Agency 

considered a number of mitigation measures that would reduce risk to listed species from gas 

cartridge use. For additional information on the proposed mitigation measures, please refer to 

the June 28, 2013, Revision to the Environmental Fate and Ecological Risk Assessment for 

Carbon Dioxide and for Carbon, Sawdust, Sodium Nitrate, Potassium Nitrate and Sulfur 

Containing Cartridges, available in the public docket (EPA-HQ-OPP-2008-0176) at 

www.regulations.gov.

In this Interim Registration Review Decision, the Agency is outlining the approach it is

taking in regards to endangered species risk. This approach is a result of both the public 

comment period on the Proposed Interim Registration Review Decision as well as subsequent 

discussions with CDPR, FWS, and USDA/APHIS personnel on the feasibility of proposed 

mitigations measures.

Bulletins Live!
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Most of the mitigation measures outlined in the Proposed Interim Registration Review 

Decision relied on the use of the Bulletins Live! Two as a means to geographically represent 

certain areas where gas cartridge use would be prohibited. Prohibition of gas cartridge use in the 

range of listed burrowing species for which an LAA determination was initially concluded

allows EPA to change this determination to “No Effect” determination for those listed species. 

The registrants agreed to include language on their gas cartridge product labels that would 

require users to check the Bulletins Live! website before making an application. The Agency 

initially proposed to issue Bulletins in Bulletins Live! for the following 11 listed species:

1. Carolina northern flying squirrel (NC, TN, VA)

2. Coachella Valley fringe-toed lizard (CA)

3. Desert slender salamander (CA)

4. Gopher tortoise (AL, LA, MS)

5. Hualapai Mexican vole (AZ)

6. Morro Bay kangaroo rat (CA)

7. Mount Graham red squirrel (AZ)

8. San Miguel Island fox (CA)

9. Santa Cruz Island fox (CA)

10. Santa Rosa Island fox (CA) 

11. Utah prairie dog (UT)

As described above in the Response to Comments section, several comments resulted in 

changes to the Agency’s proposed plan. The Agency will use Bulletins Live! Two to issue 

geographic restrictions for gas cartridge use via a requirement on the product label to check the 

website prior to application. Based on the comments on the Proposed Interim Registration 

Review Decision and subsequent dialogue with FWS and registrants including USDA/APHIS, 

EPA will issue final Bulletins for the following listed species:

1. Gopher tortoise (AL, LA, MS)

2. Hualapai Mexican vole (AZ)

3. Mount Graham red squirrel (AZ)

4. Utah prairie dog (UT) (Bulletins on EPA Reg. Nos. 9086-4, 73342-8, 4-463, 

10551-1, and 56228-2 only)

At this time, the Agency no longer plans to issue Bulletins for the following species and 

will instead consult with FWS: 

 Coachella Valley fringe-toed lizard, Desert slender salamander, Morro Bay 

kangaroo rat, San Miguel Island fox, Santa Cruz Island fox, and the Santa Rosa 

Island fox, due to comments from CDPR and the San Luis Obispo County 

Agricultural Commissioner

 Carolina northern flying squirrel, due to comments from USDA/APHIS

 Utah prairie dog Bulletins for USDA’s Large Gas Cartridge product (Reg. No. 

56228-21), due to comments from USDA/APHIS
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The Bulletin for each gas cartridge product, except for the gas cartridge products 

registered by USDA for USDA/APHIS Wildlife Service use only, will contain the following 

language:

 “Use of gas cartridges (containing some or all of the following active ingredients: 

carbon dioxide, carbon, sodium nitrate, potassium nitrate, and sulfur) is prohibited 

in this area.”

For the USDA gas cartridge products registered by USDA for USDA/APHIS Wildlife 

Service use only, the Bulletin will contain the following language:

 “Use of the gas cartridge products by USDA/APHIS personnel is prohibited in 

this area, unless USDA/APHIS has consulted with the U.S. FWS on the use 

of these products within the specified area and follows all U.S. FWS 

specifications for use.”

Separation of Uses of the USDA/APHIS Gas Cartridge Products

In the Proposed Interim Registration Review Decision, the Agency proposed the creation 

of sub-labels for USDA’s gas cartridge registrations, EPA Reg. Nos. 56228-2 (“Gas Cartridge”)

and 56228-21 (“Large Gas Cartridge”). One sub-label would be intended for use only by USDA/

APHIS Wildlife Services’ personnel and one sub-label would be intended for broad consumer 

use, including homeowners. The USDA/APHIS Wildlife Services’ product label would not be 

restricted to target species only. The consumer use sub-label would restrict use of the product to 

only target species, which allows EPA to make a “no effect” determination on 7 listed species, 

but only for the consumer use products. The other gas cartridge product labels already include 

this restriction. Since the Wildlife Services’ use product will not have a target species only 

restriction, EPA will make an NLAA determination for those 7 species and seek concurrence on 

that finding from FWS. See Appendix B below for a list of species for which EPA found a 

NLAA.

After the Proposed Interim Registration Review Decision was published, the Agency 

discussed the feasibility of the sub-label approach with State Lead Agencies that handle pesticide 

registration and enforcement, and it was determined that the sub-label approach would be 

difficult for the states to enforce. Instead, USDA has agreed to split the APHIS and consumer 

uses into their own separate registrations. This will result in a total of four APHIS gas cartridge 

registrations:

1) “Large Gas Cartridge” for APHIS use

2) “Large Gas Cartridge” for consumer use

3) “Gas Cartridge” for APHIS use

4) “Gas Cartridge” for consumer use 

APHIS has agreed to amend their existing registrations, 56228-2 (“Gas Cartridge”) and 

56228-21 (“Large Gas Cartridge”), to make them for APHIS use only. They will submit 

applications for new registration numbers for their consumer use products.

C. Final Registration Review Decision
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The Agency expects to issue a final decision on the sulfur registration review case after 

both (1) conclusion of ESA Section 7 consultation with the FWS and (2) an EDSP FFDCA 

section 408(p) determination has been made.

D. Implementation of Mitigation Measures

Once this Interim Registration Review Decision is issued, USDA/APHIS has agreed to 

amend existing registrations for USDA/APHIS Wildlife Service use and submit new 

applications for consumer use. All of the registrants will add the link to Bulletins Live! Two and 

accompanying label language to their product labels. Additionally, registrants will amend their 

labels to require use on target species only (except for the USDA/APHIS use only products). 

The registrants will submit proposed amendments to their existing product labels and 

applications for new products (USDA/APHIS) to the Agency for approval within 60 days of 

issuance of the Interim Registration Review Decision. 

E. ESA Section 7 Consultation with the U.S. Fish and Wildlife Service

Under Section 7 of the ESA, EPA is required to consult with the relevant federal agency 

when it determines that the registered uses may affect listed species (or any designated critical 

habitat for those species).The latest revision to the gas cartridge risk assessment (Revision to the 

Environmental Fate and Ecological Risk Assessment for Carbon Dioxide and for Carbon, 

Sawdust, Sodium Nitrate, Potassium Nitrate and Sulfur Containing Cartridges, dated June 28, 

2013) provides a list of the threatened and endangered species that may be affected by the use of 

gas cartridges. Through the risk mitigation measures described above, the Agency was able to 

change the effects determination of a few species (see above, Section IV, Endangered Species 

Risk Mitigation Measures). For those species specified in Section IV above where the effects 

determination was changed to No Effect, this will result in the Agency no longer having to seek 

formal Section 7 consultation with FWS. See Appendix B for a list of those species where an 

acceptable mitigation solution has been/will be implemented on the product labels that allows 

EPA to make either a “no effect” or NLAA determination. The species with an NLAA 

determination, as well as the list of species in Appendix A, will require consultation with FWS. 

The Agency intends to initiate formal Section 7 Endangered Species consultation with the FWS 

following issuance of this Interim Registration Review Decision.
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Appendix A: Listed Non-Target Species Subject to Section 7 Consultation with Fish and 

Wildlife Service

No. Species Common Name Scientific Name

1 Alabama Beach Mouse Peromyscus polionotus ammobates

2 Alameda Whipsnake Masticophis lateralis euryxanthus

3 Amargosa Vole Microtus californicus scirpensis

4 Anastasia Island Beach Mouse Peromyscus polionotus phasma

5 Arroyo Southwestern Toad Bufo californicus (=microscaphus)

6 Black-footed Ferret, Mustela nigripes

7 Blunt-nosed Leopard Lizard Gambelia silus

8 Bog Turtle Clemmys muhlenbergii

9 Buena Vista Lake Ornate Shrew Sorex ornatus relictus

10 California Red-legged Frog Rana draytonii

11 California Tiger Salamander (Central 

Valley DPS)

Ambystoma californiense

12 California Tiger Salamander (Santa 

Barbara DPS)

Ambystoma californiense

13 California Tiger Salamander (Sonoma 

DPS)

Ambystoma californiense

14 Carolina Northern Flying Squirrel Glaucomys sabrinus coloratus

15 Choctawhatchee Beach Mouse Peromyscus polionotus allophrys

16 Coachella Valley Fringe-toed Lizard Uma inornata

17 Copperbelly Water Snake Nerodia erythrogaster neglecta

18 Desert Slender Salamander Batrachoseps aridus

19 Desert Tortoise Gopherus agassizii

20 Eastern Indigo Snake Drymarchon corais couperi

21 Florida Salt Marsh vole Microtus pennsylvanicus dukecampbelli

22 Fresno Kangaroo Rat Dipodomys nitratoides exilis

23 Giant Garter Snake Thamnophis gigas

24 Giant Kangaroo Rat Dipodomys ingens

25 Gray Wolf Canis lupus

26 Hawaiian dark-rumped Petrel Pterodroma phaeopygia sandwichensis

27 Houston Toad Bufo houstonensis

28 Key Largo Woodrat Neotoma floridana smalli

29 Mississippi Gopher Frog Rana capito sevosa

30 Morro Bay Kangaroo Rat Dipodomys heermanni morroensis

31 Newell's Townsend's Shearwater Puffinus auricularis newelli

32 Northern Idaho Ground Squirrel Spermophilus brunneus brunneus

33 Pacific Pocket Mouse Perognathus longimembris pacificus

34 Perdido Key Beach Mouse Peromyscus polionotus trissyllepsis

35 Point Arena Mountain Beaver Aplodontia rufa nigra

36 Pygmy Rabbit Brachylagus idahoensis

37 Red Wolf Canus rufus

38 San Bernardino Merriams Kangaroo 

Rat

Dipodomys merriami

39 San Francisco Garter Snake Thamnophis sirtalis tetrataenia

40 San Joaquin Kit Fox Vulpes macrotis mutica

41 San Miguel Island Fox Urocyon littoralis littoralis

42 Santa Catalina Island Fox Urocyon littoralis catalinae
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No. Species Common Name Scientific Name

43 Santa Cruz Island Fox Urocyon littoralis santacruzae

44 Santa Cruz Long-toed Salamander Ambystoma macrodactylum croceum

45 Santa Rosa Island Fox Urocyon littoralis santarosae

46 Sonora Tiger Salamander Ambystoma tigrinum stebbinsi

47 Southeastern Beach Mouse Peromyscus polionotus niveiventris

48 St. Andrew Beach Mouse Microtus pennsylvanicus dukecampbelli

49 Stephens Kangaroo Rat Dipodomys stephensi

50 Tipton Kangaroo Rat Dipodomys nitratoides nitratoides

51 Utah Prairie Dog5 Cynomys parvidens

52 Wyoming Toad Bufo baxteri (=hemiophrys)

 

5 Only for USDA’s Large Gas Cartridge product (Reg. No. 56228-21)
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Appendix B: Listed Non-Target Species with Changes to EPA Effect Determinations from 

the June 28, 2013 Revised Gas Cartridge Ecological Risk Assessment

No. Species

Common Name

Scientific Name Current EPA 

Effects 

Determination

Reason for Change

1 Alabama Beach 

Mouse

Peromyscus 

polionotus 

ammobates

No Effect 

(consumer use 

products)

NLAA 

(APHIS use 

only products)

See the “Separation of Uses of the 

USDA/APHIS Gas Cartridge Products”

section above.

2 Anastasia Island 

Beach Mouse

Peromyscus 

polionotus 

phasma

No Effect 

(consumer use 

products)

NLAA 

(APHIS use 

only products)

See the “Separation of Uses of the 

USDA/APHIS Gas Cartridge Products”

section above.

3 Bog Turtle Clemmys 

muhlenbergii

No Effect 

(consumer use 

products)

NLAA 

(APHIS use 

only products)

See the “Separation of Uses of the 

USDA/APHIS Gas Cartridge Products”

section above.

4 Choctawhatchee 

Beach Mouse

Peromyscus 

polionotus 

allophrys

No Effect 

(consumer use 

products)

NLAA 

(APHIS use 

only products)

See the “Separation of Uses of the 

USDA/APHIS Gas Cartridge Products”

section above.

5 Gopher Tortoise Gopherus 

polyphemus

No Effect Changed from LAA to No Effect due to risk 

mitigation measures.

6 Hualapai 

Mexican Vole

Microtus 

mexicanus 

hualpaiensis

No Effect Changed from LAA to No Effect due to risk 

mitigation measures.

7 Island Night 

Lizard

Xantusia

riversiana

N/A Effects determination no longer needed. 

Species was delisted from the Federal List of 

Endangered and Threatend Animals on April 

1, 2014 due to recovery.

8 Mount Graham 

Red Squirrel

Tamiasciurus 

hudsonicus 

grahamensis

No Effect Changed from LAA to No Effect due to risk 

mitigation measures.

9 Perdido Key 

Beach Mouse

Peromyscus 

polionotus 

trissyllepsis

No Effect 

(consumer use 

products)

NLAA 

(APHIS use 

only products)

See the “Separation of Uses of the 

USDA/APHIS Gas Cartridge Products”

section above.
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10 Southeastern 

Beach Mouse

Peromyscus 

polionotus 

niveiventris

No Effect 

(consumer use 

products)

NLAA 

(APHIS use 

only products)

See the “Separation of Uses of the 

USDA/APHIS Gas Cartridge Products”

section above.

11 St. Andrew 

Beach Mouse

Microtus 

pennsylvanicus 

dukecampbelli

No Effect 

(consumer use 

products)

NLAA 

(APHIS use 

only products)

See the “Separation of Uses of the 

USDA/APHIS Gas Cartridge Products”

section above.

12 Utah Prairie Dog Cynomys 

parvidens

No Effect 

(small gas 

cartridges)

Changed from LAA to No Effect due to risk 

mitigation measures on small gas cartridge 

products. USDA/APHIS’s Large Gas 

Cartridge product remains LAA for the Utah 

prairie dog.
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Appendix C: Gas Cartridge Label Table for All Gas Cartridge Products

Description Amended Labeling Language for 

Gas Cartridge Use Products

Placement on Label

Language to restrict use to 

target species only 

“Only use for sites, pests, and 

application methods specified on this 

labeling.”

[Exception: For the USDA/APHIS gas 

cartridge products for USDA/APHIS 

Wildlife Services use only, this 

language is not required.]

Directions for Use

After statement about reading 

entire labeling and insert. 

Language to restrict use to 

target species only

“This product may only be used to 

control [insert pests and sites]...”

[Exception: For the USDA/APHIS gas 

cartridge products for USDA/APHIS 

Wildlife Services use only, this 

language is not required.]

Directions for Use

Under “Use Restrictions”

Endangered Species 

considerations

“Endangered Species: It is a Federal 

offense to use any pesticide in a 

manner that results in the death of an 

endangered species. Use of this 

product may pose a hazard to 

endangered or threatened species. 

When using this product, you must 

follow the measures contained in the 

Endangered Species Protection 

Bulletin for the area in which you are 

applying the product. To obtain 

Bulletins, no more than six months 

before using this product, consult 

http://www.epa.gov/espp/ or call 1-

800-447-3813. You must use the 

Bulletin valid for the month in which 

you will apply the product.”

Directions for Use

Under “Use Restrictions”

Endangered species 

considerations

“It is a Federal offense to use any 

pesticide in a manner that results in the 

death of an endangered species. See 

the Endangered Species section in the 

Directions for Use section of this 

labeling.”

Environmental Hazards section

Endangered species 

considerations

Remove references to the Gopher 

Tortoise, Hualapai Mexican Vole, and 

the Utah Prarie Dog.

[Exception: For the USDA Large Gas 

Cartridge product (Reg No. 56228-21), 

do not remove the reference to the 

Utah Prarie Dog.]

Endangered Species 

Considerations Section
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Appendix D: Geographic Ranges Maps for Species with Planned Bulletins

Figure 1. Geographic Range of Bulletins for the Mt. Graham red squirrel
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Figure 2. Geographic Range of the Bulletins for the Utah prairie dog
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Figure 3. Geographic Range of Bulletins for the Hualapai Mexican vole
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Figure 4. Geographic Range of Bulletins for the gopher tortoise