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Table of Contents 

I. Introduction ............................................................................................................................... 3

A. General Background ........................................................................................................... 4 

II. Scientific Assessments ............................................................................................................. 4

B. Environmental Assessment ................................................................................................. 4

Threatened and Endangered Species ...................................................................................... 5 

C. Human Health Assessment ................................................................................................. 5 

D. Endocrine Disruptor Screening Program ............................................................................ 6 

III. Proposed Registration Review Decision ............................................................................... 6

IV. Next Steps and Timeline ........................................................................................................ 6
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I. Introduction 

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

Registration Review Decision for Dioctyl Sodium Sulfosuccinate (DSS) which is being issued 

pursuant to 40 CFR Sections 155.57 and 155.58. DSS is co-formulated with undecylenic acid 

(UDA) for which a separate proposed registration review decision has been issued, located in the 

UDA Registration Review docket, EPA-HQ-OPP-2011-0910. A registration review decision is 

the Agency’s determination that a pesticide meets, or does not meet, the standard for registration 

in the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA). Among other things, the 

proposed registration review decision (1) states the Agency’s proposed findings with respect to 

the FIFRA standard for registration and describes the basis for such proposed findings; (2) 

identifies proposed risk mitigation measures or other remedies as needed and describes the basis 

for such proposed requirements; (3) states whether additional data are needed and, if so, 

describes what is needed; (4) specifies proposed labeling changes; and (5) identifies deadlines 

for completing any required actions. 

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 

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

unreasonable risks to human health or 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 to human health or the 

environment. 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 change occurs, products in the marketplace can be used safely. Information on this 

program is provided at: http://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 DSS (Case 4029). The following timeline 

highlights significant events that have occurred during the registration review of DSS: 

 December 22, 2010– Publication of the DSS Summary Document that included the 

Preliminary Work Plan, and was accompanied by the ecological Problem Formulation

and the human health Scoping Document in the docket (EPA-HQ-OPP-2010-1006) for a 

60-day public comment period. 

 

 May 3, 2011–Final Work Plan (FWP) for DSS is signed. No public comments were 

received during the 60-day comment period on the DSS Summary Document. In the 

PWP, EPA specifically solicited comments on environmental justice, water quality 

concerns, and trade irritants. The FWP notes that no additional ecological or human 

health data were needed for DSS registration review because sufficient information was 

available to conduct qualitative risk assessments to support a proposed registration 

review decision, pursuant to 40 CFR Section 155.53(b). 
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 March 7, 2013 – Publication of Dioctyl Sodium Sulfosuccinate Preliminary Human 

Health Risk Assessment in Support of Registration Review1 and Preliminary 

Environmental Fate and Ecological Risk Assessment for the Registration of Dioctyl 

Sodium Sulfosuccinate (Case #4029) and Undecylenic Acid (Case #4095)2 for a 60-day 

public comment period; no substantive public comments were received. 

 The documents cited above and additional information on DSS can be found in EPA’s 

public docket (EPA-HQ-OPP-2010-1006) at www.regulations.gov. 

A. General Background 

DSS is an insecticide and miticide in shampoos and spray products registered for indoor 

use on pets including dogs, cats, puppies, kittens, and reptiles to kill mites and fleas on contact. 

The first pesticide product containing DSS was registered in 1995. These products may be 

applied to the pet’s coat or to bedding and terrarium surfaces. DSS is co-formulated with the 

active ingredient undecylenic acid (UDA). As a pesticidal active ingredient, there are no food 

uses and no tolerances established. 

DSS is also an inert ingredient in several end-use agricultural and non-agricultural 

pesticide products, as well as in residential and commercial disinfectants and sanitizers. It is used 

as a wetting agent in industrial, pharmaceutical, cosmetic, and food products, as a disperser and 

solubilizing agent in foods, and as an adjuvant in tablet formation. Over the counter human 

drugs (stool softeners and laxatives) that contain DSS have much higher doses than would be 

associated with pesticide uses. As an inert ingredient, there are exemptions from the requirement 

of a tolerance established under 40 CFR 180.910 and 180.930. DSS is used in pesticide 

formulations for pre- and post-harvest application to crops and for direct application to livestock 

as an inert ingredient. DSS is classified as “Generally Recognized as Safe” (GRAS) by the Food 

and Drug Administration. 

II. Scientific Assessments 

B. Environmental Assessment 

A summary of the Agency’s environmental risk assessment is presented below. For a 

detailed discussion, see the Preliminary Ecological Risk Assessment for the Registration of 

Dioctyl Sodium Sulfosuccinate (Case #4029) and Undecylenic Acid (Case #4095) noted above. 

The Agency’s risk assessment evaluated the active ingredients from two different registration 

review cases, DSS and UDA, which are registered for use as co-formulated pet shampoo 

products. The findings of the assessment are applicable to both registration review cases. 

DSS is not expected to persist in the environment. Ester hydrolysis of DSS produces 

octanol and sulfosuccinic acid, which are both readily biodegradable and not expected to be of 

toxic concern. Terrestrial exposure is not expected to result from indoor usage and was not 

 

1 http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPP-2010-1006-0003 2 http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPP-2010-1006-0009
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assessed. DSS has the potential to enter waterways through wastewater treatment plants 

(WWTPs) after use as a pet shampoo. Risks to aquatic taxa were assessed because DSS is 

slightly acutely toxic to fish, freshwater and estuarine invertebrates, and nonvascular aquatic 

plants. 

EPA’s Office of Pollution Prevention and Toxics (OPPT) Down the Drain module EFast3

 was used to estimate DSS/UDA concentrations in receiving waters based on confidential 

production data and assumptions of 24% WWTP removal and no dilution. Toxicity endpoints 

came from open literature in the ECOTOX4

 database for DSS and chronic endpoints were 

estimated using Quantitative Structure Activity Relationship (QSAR) predictive modeling. Risk 

quotient (RQ) values are all below the Agency’s Level of Concern (LOC) for aquatic taxa. The 

estimated environmental concentration of DSS is orders of magnitude below the concentration 

expected to cause adverse effects in aquatic organisms. 

Threatened and Endangered Species 

There is no exposure to non-target terrestrial organisms, and the Agency has determined 

that there is minimal risk of adverse effects to non-target aquatic organisms. Therefore, EPA has 

made a “no effect” determination under the Endangered Species Act (ESA) for all listed species 

and designated critical habitat for such species, and has therefore concluded that consultation 

with the Fish and Wildlife Service and the National Marine Fisheries Service under ESA section 

7(a)(2) is not required. 

C. Human Health Assessment 

The Agency considered the HED scoping document, its supporting documents, and the 

most updated Agency science policies and risk assessment methodologies to prepare a qualitative 

risk assessment in support of the registration review of DSS. Because of the low toxicity of 

DSS, its classification by the FDA as GRAS, and its use as a pharmaceutical drug in higher 

doses than would result from pesticide uses, the Agency determined that a quantitative human 

health risk assessment was not required under registration review. For a detailed discussion, see 

the Dioctyl Sodium Sulfosuccinate Preliminary Human Health Risk Assessment in Support of 

Registration Review noted above. A summary of the Agency’s human health risk assessment is 

presented below. 

There are no dietary, residential, occupational, or aggregate risks of concern for DSS. All 

toxicity data requirements were waived when DSS was registered, except for acute toxicity 

studies; therefore endpoints have not been selected for DSS. DSS has no registered food uses as 

a pesticide and no residue chemistry data were required or submitted to support its use as an 

active ingredient or its inert uses in conventional and antimicrobial pesticide formulations. As an 

inert ingredient, DSS is exempted from the requirement for a tolerance. It is used in pesticide 

formulations intended for pre- and post- harvest applications to raw agricultural commodities and 

direct application to livestock. Because of the low toxicity of DSS, quantitative residential 

handler, occupational, post-application exposure and aggregate assessments were not required. It 

 

3 http://www.epa.gov/oppt/exposure/index.htm

4 http://cfpub.epa.gov/ecotox/
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has not been determined that DSS shares a common mechanism of toxicity with other chemicals; 

therefore a cumulative risk assessment was also not required. 

D. Endocrine Disruptor Screening Program 

Pursuant to FFDCA Section 408(p)(4), EPA has exempted DSS from the requirements of 

the EDSP in an Administrative Order entitled Exemption of Dioctyl Sodium Sulfosuccinate (DSS) 

and Undecylenic Acid (UDA) from the Requirements of the Endocrine Disruptor Screening 

Program, dated April 11, 2014. The Order is available in the docket for this registration review 

at EPA-HQ-OPP-2010-1006. The Administrative Order describes the analysis and rationale that 

the Agency used to evaluate DSS in order to determine that it qualifies for the exemption. 

III. Proposed Registration Review Decision 

In accordance with 40 CFR Sections 155.57 and 155.58, the Agency is issuing this 

Proposed Registration Review Decision document. The Agency has made the following 

proposed decision: (1) no additional data are required at this time; and (2) no changes to the 

affected registrations or their labeling are needed at this time. In addition, EPA does not expect 

DSS to have direct or indirect adverse effects to non-listed and listed species or to adversely 

modify any designated critical habitat for such species. EPA has made a “no effect” 

determination under the ESA for all listed species and designated critical habitat for such 

species. Further, the Agency has also determined that based on its structure, chemical nature, and 

history of uses for human consumption and pharmaceutical applications, DSS is exempt from the 

EDSP requirement. EPA’s proposed Registration Review Decision determination for DSS is that 

the pesticide meets the standard for registration under FIFRA. 

IV. Next Steps and Timeline 

A Federal Register Notice will announce the availability of this Proposed Registration 

Review Decision in the DSS and allow a 60-day comment period. If there are no significant 

comments or additional information submitted to the docket during the comment period that 

leads the Agency to change its decision, EPA will issue its registration review decision for DSS 

(case 4029).