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Docket Number EPA-HQ-OPP-2010-1006

www.regulations.gov

Dioctyl Sodium Sulfosuccinate Final Work Plan

Registration Review

April 2011

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DIOCTYL SODIUM SULFOSUCCINATE FINAL WORK PLAN

Introduction

This is the Environmental Protection Agency’s (EPA’s) Final Work Plan for the registration review 

of Dioctyl sodium sulfosuccinate (DSS). This work plan includes the expected registration review 

timeline. The work plan also addresses public comments received concerning the Preliminary Work 

Plan in the Summary Document, which was posted in the DSS registration review docket (EPAHQ-OPP-2010-1006), and any other comments concerning the initial docket postings. The 

Summary Document provided information on what EPA knows about the pesticide and what 

additional risk analyses and data or information the Agency believes are needed to make a 

registration review decision.

The Agency is implementing the registration review program pursuant to Section 3(g) of the Federal 

Insecticide, Fungicide, and Rodenticide Act (FIFRA), and will review each registered pesticide 

every 15 years to determine whether it continues to meet the FIFRA standard for registration. 

Changes in science, public policy, and pesticide use practices will occur over time. The registration 

review program is intended to make sure that, as the ability to assess risk evolves and as policies and 

practices change, all registered pesticides continue to meet the statutory standard. The public phase 

of registration review begins when the initial docket is opened for each case. Information on this 

program is provided at: http://www.epa.gov/oppsrrd1/registration_review/.

Dioctyl sodium sulfosuccinate (DSS) is the active ingredient in pet shampoos and spray products, 

which are registered in combination with undecylenic acid. As a pesticidal active ingredient, there 

are no food uses and there are no tolerances established for DSS. DSS is also used as an inert 

ingredient in multiple end-use pesticide products for agricultural and non-agricultural areas; in 

disinfectants and sanitizers used in residential and commercial settings; and as a wetting agent in 

industrial, drug, cosmetic, and food products. Some of the drug products contain DSS for use as a 

stool softener and laxative. As an inert ingredient there are exemptions from the requirement of a 

tolerance established for the sodium salt of DSS under 40 CFR 180.910 and 40 CFR 180.930. These 

exemptions allow DSS as an inert ingredient to be used in pesticide formulations for pre- and postharvest application to crops and direct application to livestock. 

DSS was first registered as an active ingredient in 1995. Therefore, a Reregistration Eligibility 

Decision (RED) document was not completed for DSS. For registration review only the use of DSS 

as an active ingredient (in pet shampoos) will be considered. Its use as an inert ingredient will be 

considered in the risk assessments for those active ingredients with which it is formulated. In any 

case, the non-pesticidal uses of DSS are expected to dominate both human and wildlife exposure to 

this chemical.
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Comments Received on Preliminary Work Plan:

No comments were received during the 60-day public comment period on the planned ecological 

assessment and human health scoping document discussed in the Preliminary Work Plan. In the 

Preliminary Work Plan, EPA also solicited comments on three specific topics: environmental 

justice, water body impairment, and trade irritants. No comments or information were received 

during the comment period concerning these three topics. 

Anticipated Risk Assessment and Data Needs

The Agency does not intend to require additional data on dioctyl sodium sulfosuccinate. The 

Agency plans to conduct a comprehensive ecological risk assessment, including an endangered 

species risk assessment, for the pesticidal uses of dioctyl sodium sulfosuccinate. Below is a 

summary of the issues relevant to the registration review of dioctyl sodium sulfosuccinate. 

Ecological Risk:

• No ecological risk assessment has been completed for DSS as pesticidal active ingredient. 

DSS was evaluated as an inert ingredient in June, 2006. The review of DSS as an inert 

ingredient did not identify any ecological risks of concern to fish.

• The Agency has not conducted an ecological risk assessment that supports a complete 

endangered species determination for dioctyl sodium sulfosuccinate. The ecological risk 

assessment planned during registration review will allow the Agency to determine whether 

dioctyl sodium sulfosuccinate’s use has “no effect” or “may affect” federally listed 

threatened or endangered species (listed species) or their designated critical habitats. When 

an assessment concludes that a pesticide’s use “may affect” a listed species or its designated 

critical habitat, the Agency will consult with the U.S. Fish and Wildlife Service (FWS)

and/or National Marine Fisheries Service (NMFS) (the Services), as appropriate.

• Due to the nature of DSS as a shampoo use on pets, mammals, and reptiles, no data are 

needed. In addition, because DSS as an active ingredient is registered for indoor uses and 

according to the updated data requirements in 40 CFR part 158, it is anticipated that no

additional ecological data are required for the indoor uses.

Please refer to the “Registration Review – Preliminary Problem Formulation for the Ecological Risk 

and Drinking Water Exposure Assessments for Dioctyl Sodium Sulfosuccinate,” dated December 

20, 2010, for a more detailed discussion of the anticipated ecological risk assessment.
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Human Health Risk:

• No human health risk assessment has been completed for DSS as a conventional pesticide 

active ingredient.

• Because of the extensive literature data available on DSS, its low toxicity, FDA’s approval of 

the chemical as a drug for use at much higher doses than would be experienced as a result of 

pesticide-related uses, and the chemical’s classification by FDA as Generally Recognized as 

Safe (GRAS) (21 CFR 178.3400), the Agency concludes that additional toxicity data are not 

required.

• A quantitative human health risk assessment is not required under registration review for the 

existing uses of DSS. There are no risks of concern associated with DSS. No dietary or 

residential exposure assessment or aggregate risk assessment is required.

• DSS is exempted from the requirements of tolerances under 40 CFR 180.910 and 180.930. 

No residue chemistry data is required for DSS.

Please refer to the “Dioctyl Sodium Sulfosuccinate. Human Health Assessment Scoping Document 

in Support of Registration Review,” dated December 16, 2010 located in the docket for a detailed 

discussion of the human health risk assessment status.

 

Endocrine Disruptor Screening Program 

As required by FIFRA and FFDCA, EPA reviews numerous studies to assess potential adverse 

outcomes from exposure to chemicals. Collectively, these studies include acute, subchronic and 

chronic toxicity, including assessments of carcinogenicity, neurotoxicity, developmental, 

reproductive, and general or systemic toxicity. These studies include endpoints which may be 

susceptible to endocrine influence, including effects on endocrine target organ histopathology, organ 

weights, estrus cyclicity, sexual maturation, fertility, pregnancy rates, reproductive loss, and sex 

ratios in offspring. For ecological hazard assessments, EPA evaluates acute tests and chronic 

studies that assess growth, developmental and reproductive effects in different taxonomic groups. 

As part of its reregistration decision, EPA reviewed these data and selected the most sensitive 

endpoints for relevant risk assessment scenarios from the existing hazard database. However, as 

required by FFDCA section 408(p), methomyl is subject to the endocrine screening part of the 

Endocrine Disruptor Screening Program (EDSP). 

EPA has developed the EDSP to determine whether certain substances (including pesticide active 

and other ingredients) may have an effect in humans or wildlife similar to an effect produced by a 

“naturally occurring estrogen, or other such endocrine effects as the Administrator may designate.” 

The EDSP employs a two-tiered approach to making the statutorily required determinations. Tier 1 

consists of a battery of 11 screening assays to identify the potential of a chemical substance to 
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interact with the estrogen, androgen, or thyroid (E, A, or T) hormonal systems. Chemicals that go 

through Tier 1 screening and are found to have the potential to interact with E, A, or T hormonal 

systems will proceed to the next stage of the EDSP where EPA will determine which, if any, of the 

Tier 2 tests are necessary based on the available data. Tier 2 testing is designed to identify any 

adverse endocrine-related effects caused by the substance, and establish a dose-response relationship 

between the dose and the E, A, or T effect. 

Under FFDCA section 408(p), the Agency must screen all pesticide chemicals. Between October 

2009 and February 2010, EPA issued test orders/data call-ins for the first group of 67 chemicals, 

which contains 58 pesticide active ingredients and 9 inert ingredients. Dioctyl sodium 

sulfosuccinate was not included on that list. For further information on the status of the EDSP, the 

policies and procedures, the list of 67 chemicals, future lists, the test guidelines and the Tier 1 

screening battery, please visit our website: http://www.epa.gov/endo/. 

 

Timeline

The Agency has created the following estimated timeline for the completion of the dioctyl sodium 

sulfosuccinate registration review.

Registration Review for Dioctyl Sodium Sulfosuccinate– Projected Registration Review 

Timeline

Activities Estimated Date

Opening the docket

Open Docket and Public Comment Period 2010 – December

Close Public Comment 2011 – February

Case Development

Final Work Plan 2011 – May

Open Public Comment Period for Draft Risk Assessments 2012 – July- Sept.

Close Public Comment Period 2012 – Oct. –Dec.

Registration Review Decision

Open Public Comment Period for Proposed Registration Review 

Decision

2013 – Jan. - March

Close Public Comment Period 2013- April - June 

Registration Review Decision and Begin Post-Decision Follow-up 2013

Total (years) 3

Next Steps

The Agency plans to conduct a comprehensive ecological risk assessment, including an endangered 

species risk assessment, for the pesticidal uses of dioctyl sodium sulfosuccinate. The draft of that 

risk assessment will be available for public comment in 2012.