Docket Number EPA-HQ-OPP-2011-0910

www.regulations.gov

Undecylenic Acid

Summary Document

Registration Review: Initial Docket

December 2011

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TABLE OF CONTENTS

 Page #

I. Preliminary Work Plan (PWP) 4

II. Fact Sheet 9

This Preliminary Work Plan and Fact Sheet summarize the Environmental Protection Agency’s 

current position based on the following documents:

1. Registration Review – Preliminary Problem Formulation for the Ecological Risk and 

Drinking Water Exposure Assessments for Undecylenic Acid. August 9, 2011.

2. Undecylenic acid. Human Health Assessment Scoping Document in Support of 

Registration Review. December 14, 2011.

3. BEAD Chemical Profile for Registration Review: Undecylenic acid. July 13, 2011.

Supporting documents for the registration review of undecylenic acid are located in docket EPAHQ-OPP-2011-0910 at www.regulations.gov. 
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I. PRELIMINARY WORK PLAN

Introduction

The Food Quality Protection Act (FQPA) of 1996 mandated a registration review program. All 

pesticides distributed or sold in the United States (U.S.) generally must be registered by the 

Environmental Protection Agency (EPA or the Agency), 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 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/. 

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. The 

Agency will consider benefits information and data as required by FIFRA. The public phase of 

registration review begins when the initial docket is opened for each case. The docket is the 

Agency’s opportunity to state what it knows about the pesticide and what additional risk analyses 

and data or information it believes are needed to make a registration review decision. After 

reviewing and responding to comments and data received in the docket during this initial comment 

period, the Agency will develop and commit to a final work plan and schedule for the registration 

review of undecylenic acid.

Undecylenic acid is an insecticide and miticide registered for use to kill fleas and mites on pets. It is 

an active ingredient in pet shampoos and pet spray products, which are registered in combination 

with dioctyl sodium sulfosuccinate (DSS). As a pesticidal active ingredient, there are no food uses 

and no tolerances established for undecylenic acid. In addition to its pesticidal uses registered by 

EPA, undecylenic has other uses in products unrelated to the EPA registered uses on pets. 

Undecylenic acid has antifungal properties and is approved by the U.S. Food and Drug 

Administration (FDA) as an over-the-counter drug to treat various skin conditions in humans. It can 

also be used as a flavoring ingredient, and is classified as “Generally Recognized as Safe” (GRAS). 

Undecylenic acid is an organic unsaturated fatty acid that has structural similarities to fatty acids 

found in the diet.

Pesticide products containing undecylenic acid as an active ingredient were first registered in 1986. 

Therefore, it was not subject to the reregistration requirements of FIFRA and a Reregistration 

Eligibility Decision (RED) document was not completed for undecylenic acid. For registration 

review, only the use of undecylenic acid as a pesticide active ingredient (in pet shampoos and pet 

sprays) will be considered.
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Anticipated Risk Assessment and Data Needs

The Agency does not intend to require additional data on undecylenic acid. The Agency plans to

conduct a comprehensive ecological risk assessment, including an endangered species risk 

assessment, for the pesticidal uses of undecylenic acid. Below is a summary of the issues relevant to 

the registration review of undecylenic acid. 

Ecological Risk:

• No ecological risk assessment has been completed for undecylenic acid as a pesticidal active 

ingredient.

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

endangered species determination for undecylenic acid. The ecological risk assessment 

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

acid’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 undecylenic acid as a shampoo use on pets (mammals and reptiles), no 

additional data on terrestrial animals (birds, reptiles, and terrestrial-phase amphibians) are 

anticipated as being needed for this registration review. In addition, because undecylenic 

acid is registered for indoor uses, it is anticipated that no additional ecological data will be

required for this registration review.

• Please refer to the Registration Review – Preliminary Problem Formulation for the 

Ecological Risk and Drinking Water Exposure Assessments for Undecylenic Acid, dated

August 9, 2011, located in docket EPA-HQ-OPP-2011-0910 at www.regulations.gov, for a 

more detailed discussion of the anticipated ecological risk assessment.

Human Health Risk:

• No human health risk assessment has been completed for undecylenic acid as a pesticidal

active ingredient.

• Because of the extensive literature data available on undecylenic acid, 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 will not be needed for this registration review.
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• A quantitative human health risk assessment is not required under registration review for the 

existing uses of undecylenic acid. There are no risks of concern associated with undecylenic 

acid. No dietary or residential exposure assessment or aggregate risk assessment is required.

• There are no tolerances established for undecylenic acid.

• Please refer to the Undecylenic acid. Human Health Assessment Scoping Document in 

Support of Registration Review, dated December 14, 2011, located in docket EPA-HQ-OPP2011-0910 at www.regulations.gov, for a detailed discussion of the human health risk 

assessment status.

 

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 most recent registration decision for undecylenic acid, 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), undecylenic acid is subject to the endocrine 

screening part of the Endocrine Disruptor Screening Program (EDSP). 

Endocrine Disruptor Screening Program

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 may 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. Undecylenic acid 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, 
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requiring the submission of EDSP screening assays for undecylenic acid. 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 projected timeline for the completion of the undecylenic acid registration review is presented in 

Table 1.

Table 1. Projected Undecylenic Acid Registration Review Timeline

Activity Estimated Date

Opening the Docket

Open Docket and Open Public Comment Period 2011 – December

Close Public Comment Period 2012 – February

Case Development

Develop Final Work Plan (FWP) 2012 – May

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

Close Public Comment Period 2012 – Oct. – Dec.

Registration Review Decision

Develop Proposed Registration Review Decision and Open Public 

Comment Period

2013 – Jan. – March

Close Public Comment Period 2013 – April – June

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

Total (years) 3

Guidance for Commenters

The public is invited to comment on EPA’s preliminary work plan and rationales. The Agency will 

carefully consider all comments, as well as any additional information or data provided in a timely 

manner, prior to issuing a final work plan for the undecylenic acid case.

Trade Irritants:

Through the registration review process, the Agency intends to solicit information on trade irritants 

and, to the extent feasible, take steps toward facilitating irritant resolution. Growers and other 

stakeholders are asked to comment on any trade irritant issues resulting from lack of Maximum 

Residue Limits (MRLs) or disparities between U.S. tolerances and MRLs in key export markets, 

providing as much specificity as possible regarding the nature of the concern.

Environmental Justice:

EPA seeks to achieve environmental justice, the fair treatment and meaningful involvement of all 

people, regardless of race, color, national origin, or income, in the development, implementation, 
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and enforcement of environmental laws, regulations, and policies. To help address potential 

environmental justice issues, the Agency seeks information on any groups or segments of the 

population who, as a result of their location, cultural practices, or other factors, may have atypical, 

unusually high exposure to undecylenic acid compared to the general population. Please comment if 

you are aware of any sub-populations that may have atypical, unusually high exposure, compared to 

the general population.

Water Quality:

Undecylenic acid is not identified as a cause of impairment for any water bodies listed as impaired 

under section 303(d) of the Clean Water Act1. In addition, no Total Maximum Daily Loads 

(TMDLs) have been developed for undecylenic acid2. More information on impaired water bodies 

and TMDLs can be found at the Agency’s website3. The Agency invites submission of water quality 

data for this pesticide. To the extent possible, data should conform to the quality standards in 

Appendix A of the OPP Standard Operating Procedure: Inclusion of Impaired Water Body and 

Other Water Quality Data in OPP’s Registration Review Risk Assessment and Management 

Process4 in order to ensure they can be used quantitatively or qualitatively in pesticide risk 

assessments.

Next Steps

After the 60-day comment period closes, the Agency will consider and respond to any comments 

received in a timely manner. The Agency expects to issue a Final Work Plan for undecylenic acid in 

May 2012.

 1 http://iaspub.epa.gov/tmdl_waters10/attains_nation_cy.cause_detail_303d?p_cause_group_id=885

2 http://iaspub.epa.gov/tmdl_waters10/attains_nation.tmdl_pollutant_detail?p_pollutant_group_id=885&p_pollutant_group_name=PESTICIDES 3 http://www.epa.gov/owow/tmdl/

4 http://www.epa.gov/oppsrrd1/registration_review/water_quality_sop.htm
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II. FACT SHEET

Background Information

• Registration Review Case Number: 4095

• Pesticide Chemical (PC) Code: 085501

• Chemical Abstracts Service (CAS) Number: 112-38-9

• Undecylenic acid was first registered in the U.S. in 1986. 

• Since pesticide products containing undecylenic acid were first registered after 1984, 

undecylenic acid was not subject to the reregistration requirements of FIFRA; therefore, 

there is no Reregistration Eligibility Decision (RED) document for undecylenic acid. 

• Technical registrant: Natural Chemistry, Inc.

• Currently, there are two only two products containing undecylenic acid as an active 

ingredient for conventional pesticide uses. 

• EPA Registration Numbers: 45729-2 and 45729-4

• Pesticide Re-evaluation Division (PRD) Contact: Tom Myers (myers.tom@epa.gov)

• Registration Division (RD) Contact: Richard Gebken (gebken.richard@epa.gov).

Use and Usage Information

• No usage information is available. 

Pending Actions

• There are no recent or pending actions for undecylenic acid.

Ecological Risk Assessment Status

The following are key findings, from both open literature and from studies submitted by the 

technical registrant, regarding the environmental fate, ecological effects and risks of undecylenic 

acid. Please refer to the Registration Review – Preliminary Problem Formulation for the Ecological 

Risk and Drinking Water Exposure Assessments for Undecylenic Acid, dated August 9, 2011, located 

in docket EPA-HQ-OPP-2011-0910 at www.regulations.gov, for a detailed discussion of the 

ecological risk assessment.
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Ecological Risks:

• No ecological risk assessment has been completed for undecylenic acid as a pesticidal active 

ingredient.

Human Health Risk Assessment Status

The following are key findings, from both open literature and from studies submitted by the 

technical registrant, regarding the human health effects and risks of undecylenic acid. Please refer to 

the Undecylenic acid. Human Health Assessment Scoping Document in Support of Registration 

Review, dated December 14, 2011, located in docket EPA-HQ-OPP-2011-0910 at 

www.regulations.gov, for a detailed discussion of the human health risk assessment status.

Hazard Characterization:

• Undecylenic acid has low acute oral, dermal and inhalation toxicity. It is neither a skin 

sensitizer nor a skin or eye irritant. Results of long-term toxicity and reproduction studies in 

the literature did not demonstrate any significant toxicity of undecylenic acid.

Dietary Exposure:

• As an active ingredient, there are no food uses for undecylenic acid and there are no 

tolerances established for undecylenic acid.

• Based on the low toxicity of undecylenic acid, a quantitative dietary risk assessment is not 

required. The Agency believes that there are no dietary risks of concern associated with the 

established uses of undecylenic acid.

Residential Exposure: 

• There are residential uses for the active ingredient undecylenic acid in shampoo and spray pet 

products. Due on the low toxicity of undecylenic acid, the Agency believes that there are no

residential risk of concern. 

Aggregate Risk:

• Since quantitative dietary and residential exposure assessments are not required for 

undecylenic acid, a quantitative aggregate assessment is not required either. Based on the 

low hazard associated with undecylenic acid, the Agency believes that aggregate risks are not 

of concern.
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Occupational Risk:

• Due to the low toxicity of undecylenic acid, the Agency believes there are no occupational 

risks of concern. 

Cumulative Assessment:

• The Agency has not determined that undecylenic acid 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.

Incidents

Ecological Incidents:

• Based on the use of undecylenic acid as a pet shampoo and low toxicity, no ecological 

incidents are expected. The Agency will search the incident database before the issuance of 

the final work plan.

Human Health Incidents:

• Both the OPP Incident Data System (IDS) and the Centers for Disease Control and 

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

Event Notification System for Occupational Risk-Pesticides (SENSOR) databases were 

consulted.

• No incident involving undecylenic acid was reported between 1998 – 2007, the period 

covered in incident database for undecylenic acid.

Tolerances and International Harmonization

• There are no tolerances established for undecylenic acid.

Data Call-In Status

• There have been no data call-ins associated with undecylenic acid.

 Labels

• Active Section 3 labels for undecylenic acid can be obtained from the Pesticide Product 

Label System (PPLS) website: http://oaspub.epa.gov/pestlabl/ppls.home.