Page 2 of 7

1.0 Executive Summary

HED has prepared a qualitative human health risk assessment to support registration review for 

the uses of dioctyl sodium sulfosuccinate (DSS) as an active ingredient and as an inert ingredient 

in pesticides. HED primarily considered the HED scoping document, and its supporting 

documents, in support of registration review (LaMay, 12/10/10, D379581). Based on the low 

toxicity of DSS, the chemical’s classification by the U.S. FDA as Generally Recognized as Safe 

(GRAS) as a food additive (21 CFR 178.3400), and its use as a pharmaceutical drug 

administered in much higher doses than would result from any potential pesticide exposures, 

HED has determined that a quantitative human health risk assessment is not required under 

registration review for the existing uses of DSS.

Dioctyl sodium sulfosuccinate (DSS) is used as both an active ingredient and as an inert

ingredient. As an active ingredient, there are no food uses. DSS is listed as the active ingredient 

(insecticide) in pet shampoos and pet spray products, which are registered in combination with 

undecylenic acid (PC 085501). 

DSS as an inert ingredient is used 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. As an inert ingredient 

there are exemptions from the requirement of a tolerance established for DSS under 40 CFR 

180.910 and 180.930. These exemptions allow DSS as an inert ingredient to be used in pesticide 

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

Toxicity information for DSS is largely from literature studies; guideline toxicity studies are not 

available, and have been previously waived (except acute studies, which have been submitted) 

by the Office of Pesticide Programs (OPP) because of its low toxicity. Dioctyl sodium 

sulfosuccinate has low acute oral, dermal and inhalation toxicity. It is neither a skin sensitizer 

nor a skin or eye irritant. Toxicity to offspring occurred in the reproduction and developmental 

studies only at high doses. The subchronic toxicity, chronic toxicity, and mutagenicity studies 

did not demonstrate any significant toxicity of DSS.

No data deficiencies were identified for toxicology, residue chemistry or occupational and 

residential exposure. There are no dietary, residential, aggregate or occupational risks of concern 

for DSS.

2.0 Regulatory Recommendations

Sufficient data are available to support HED’s decision to waive generic mammalian toxicity 

data requirements for dioctyl sodium sulfosuccinate. There are no outstanding data

requirements.

Tolerances for residues of DSS in food are not required. There are exemptions from the 

requirement of a tolerance currently established for DSS under 40 CFR 180.910 and 180.930.

HED has no objection to continuing registration of the current DSS pesticide products.
Page 3 of 7

3.0 Introduction

Dioctyl sodium sulfosuccinate is an active ingredient (insecticide) used in pet shampoos and pet 

spray products which are registered in combination with undecylenic acid (PC 085501). The 

currently registered products are formulated as an emulsifiable concentrate (45729-2) and as a 

ready-to-use liquid (45729-4) and may be used on cats, dogs, and reptiles. The structure, 

chemical names, and other identifiers are found in the chemical identity table below.

Table 3.1. Chemical Identity

Common Name Dioctyl sodium sulfosuccinate

Chemical Name sodium 1,4-bis(2-ethylhexoxy)-1,4-dioxobutane-2-sulfonate

PC Code 079027

Chemical Abstracts No. 577-11-7

Registration Review 

Case No. 4029

Chemical Class e.g. organophosphate, dinitroaniline, etc.

Chemical Structure

4.0 Hazard Identification and Dose-Response Assessment

The hazard information in this document came principally from reports assessing DSS (PC code 

079027) as an active ingredient (Steve Johnson, 8/4/95) and as an inert ingredient (Laura Bailey, 

9/28/04). For the assessment of DSS as an active ingredient, all toxicity study data requirements, 

except for acute toxicity, were waived. The requirements were waived because of the extensive 

data available in the open literature for this chemical showing very low toxicity, and also because 

of the approval by the Food and Drug Administration (FDA) in over-the-counter human drug 

products such as stool softeners and laxatives at much higher doses of DSS than would be 

associated with pesticide-related uses.

The review of DSS as an inert ingredient relied upon toxicity studies assessed by the 

International Programme on Chemical Safety/World Health Organization (IPCS/WHO), the 

Food and Agriculture Organization of the United Nations (FAO), a report submitted by the 

Synthetic Organic Chemical Manufacturers Association (SOCMA) Sulfossucinates Group under 

the High Production Volume (HPV) Challenge Program, and information from the Hazardous 

Substances Databank (HSDB). 

Results of acute toxicity studies submitted by the registrant for DSS found that DSS was of low 

acute toxicity: toxicity category IV for acute oral testing and category III for acute dermal and 

inhalation testing. DSS was in toxicity category III for eye irritation and category IV for dermal 

irritation. DSS was not a dermal sensitizer. 
Page 4 of 7

Studies reported and assessed by WHO, FAO, SOCMA, and from the HSDB included 

subchronic toxicity, chronic toxicity, mutagenicity, developmental effect, and reproduction 

studies. Subchronic oral toxicity studies in rats, rabbits, monkeys, dogs, and guinea pigs 

reported decreased weight gain, which may have been due to decreased palatability, because 

administration of DSS was associated with decreased food consumption. No pathological 

changes were noted in a 2-year feeding study in rats. Two mutagenicity studies, an Ames assay 

and a chromosomal aberrations assay in CHO cells were negative. 

DSS was tested in two 3-generation reproductive studies. There was decreased pup survival at 

250 and 500 mg/kg/day in one study. Doses in the second reproduction study were 0, 50, 250, or 

500 mg/kg/day. The only effects observed were reduced parental and pup body weights, but 

there was no effect on survival or reproductive parameters in this study. Developmental toxicity 

testing in rats found increased fetal resorptions, exencephaly, microphthalmia, and spina bifida at 

1,000 mg/kg/day with a NOAEL of 500 mg/kg/day. 

Although toxicity to offspring occurred in the reproduction and developmental studies, there are 

few concerns for exposure because 1) the effects occurred at high doses and 2) DSS is an overthe-counter drug administered in high doses to humans (500 mg for adults and 40 mg for 

children < 3 years of age), and was cleared by FDA for these uses. According to the previous 

2006 EPA assessment, the only warning in the Physician's Desk Reference for pregnant women 

taking DSS as a drug is to notify their doctor before taking the drug. 

Because of the extensive literature data available for 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) as a food additive (21 CFR 178.3400), HED concludes that additional toxicity data are 

not required, and that a quantitative risk assessment for pesticide-related uses is not required. 

Since this chemical was registered, there are now OPP guideline study requirements for 

neurotoxicity and immunotoxicity, however, these studies can be waived for the same reasons 

that the original guideline studies were waived, namely the long history of this chemical as a 

human drug and because significant toxicity is not expected. Endpoints were not selected for 

this chemical because the toxicity studies were waived. There are no reports of increased 

sensitivity to children from use of this product, nor is there any reason to anticipate sensitivity to 

children, therefore the FQPA safety factor can be reduced to 1X. 

5.0 Dietary Exposure and Risk Assessment

As an active ingredient, there are no food uses for DSS. However, exemptions from the 

requirement of a tolerance are established for DSS (as sodium dioctylsulfosuccinate) under 40 

CFR 180.910 and 180.930 which allow uses as inert ingredients in formulations intended for preand post-harvest application to raw agricultural commodities and permits direct use on livestock. 

No residue chemistry data were submitted or are required to support the non-food uses of DSS as 

an active ingredient. Further, no residue chemistry data were submitted to support the 

established inert ingredient uses, and based on the low toxicity of DSS, residue chemistry data 

are not required to support the established inert uses in both conventional and antimicrobial 
Page 5 of 7

pesticide formulations. Further, also based on the low toxicity of DSS, a quantitative dietary risk 

assessment is not required. HED concludes that there are no dietary risks of concern associated 

with the established uses of DSS.

6.0 Residential (Non-Occupational) Exposure/Risk Characterization

There are residential (non-occupational) uses for the active ingredient DSS in pet shampoo and 

spray. The inert ingredient DSS can also be used in pesticide products used in non-agricultural 

areas and it can be used as an inert ingredient in disinfectants and sanitizers for household uses. 

Residential exposure was not previously quantitatively assessed for either active or inert uses in 

pesticide products. Because of the low toxicity of DSS, quantitative residential handler and 

postapplication exposure assessments are not required. HED concludes there are no residential 

exposure risks of concern. 

7.0 Aggregate Exposure/Risk Characterization

An aggregate assessment considers exposures from food, residential uses, and drinking water. 

As quantitative dietary and residential exposure assessments are not required for DSS acid, a 

quantitative aggregate assessment is not required either. Based on the low hazard associated 

with DSS, HED concludes that aggregate risks are not of concern.

8.0 Cumulative Exposure/Risk Characterization

The Agency has not determined that DSS shares a common mechanism of toxicity with other 

chemical substances; therefore, at this time, a cumulative risk assessment to support registration 

review is not required.

9.0 Occupational Exposure/Risk Characterization

There is potential for occupational (handler and postapplication) exposure to DSS as a pet 

product. Because of the low toxicity of DSS, a quantitative occupational exposure assessment is 

not required for these pet product uses. HED concludes there are no occupational exposure risks 

of concern. 

10.0 Public Health and Pesticide Epidemiology Data

A summary report listing incidents for DSS is available (D380163, K. Oo). No incidents were 

reported to either OPP Incident Data System (IDS) or the Centers for Disease Control and 

Prevention/National Institute for Occupational Safety and Health (CDC/NIOSH) Sentinel Event 

Notification System for Occupational Risk (SENSOR) database for DSS. Because there are no 

incident cases reported for DSS, there does not appear to be a concern at this time that would 

warrant further investigation. 
Page 6 of 7

11.0 Tolerance Assessment and International Harmonization

There are no tolerances established for DSS; therefore, there are no issues with respect to 

international harmonization associated with this registration review action.

12.0 Environmental Justice

Potential areas of environmental justice concerns, to the extent possible, were considered in the 

human health risk assessment, in accordance with U.S. Executive Order 12898, "Federal Actions 

to Address Environmental Justice in Minority Populations and Low-Income Populations," 

http://www.eh.doe.gov/nepa/tools/guidance/Volume1/2-6-EO_12898envjustice.pdf). The Office 

of Pesticide Programs (OPP) typically considers the highest potential exposures from the legal 

use of a pesticide when conducting human health risk assessments, including, but not limited to, 

people who obtain drinking water from sources near agricultural areas, the variability of diets 

within the U.S., and people who may be exposed when harvesting crops. Should these highest 

exposures indicate potential risks of concern, OPP further refines the risk assessments to ensure 

that the risk estimates are based on the best available information.

13.0 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. EPA has reviewed the available data and endpoints were not selected for this 

chemical because significant toxicity is not expected and the toxicity studies were waived. 

However, as required by FFDCA section 408(p), dioctyl sodium sulfosuccinate 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 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 
Page 7 of 7

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 is not among the group of 58 pesticide active ingredients on the initial list 

to be screened under the EDSP. Accordingly, as part of registration review, EPA will issue 

future EDSP orders/data call-ins, requiring the submission of EDSP screening assays for dioctyl 

sodium sulfosuccinate. 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/.

14.0 Human Studies

No human studies have been relied on for dioctyl sodium sulfosuccinate risk assessments.

15.0 Data Requirements

None.

16.0 References

Author Barcode Date Title

J. Hayes NA 7/13/1995 EPA Reg. No./File Symbol 45729-E

S. Johnson NA 8/4/1995

New Chemicals: Consideration of Unconditional Registration for 

the New Chemicals Dioctyl sodium sulfosuccinate and 

Undecylenic acid for use on dogs and cats to control fleas.

L. Bailey NA 9/28/2004

Butanedioic acid, sulfo-, 1,4-bis (2-ethylhexyl) ester, sodium salt: 

Tolerance Reassessment Decision Document PC Codes 079027; 

790130.

P. Wagner NA 6/30/2006

Inert Reassessments: Two Exemption from the Requirement of a 

Tolerance for Sodium Dioctyl Sulfosuccinate (CAS Reg. No. 577-

11-7)

M. Kaul NA 6/2/2010 BEAD Chemical Profile for Registration Review: Dioctyl Sodium 

Sulfosuccinate

K. Oo D380163 8/24/2010 Updated Review of Dioctyl Sodium Sulfosuccinate Incident 

Reports

A.LaMay 379581 12/16/10 Dioctyl Sodium Sulfosuccinate. Human Health Assessment 

Scoping Document in Support of Registration Review.