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DEET – Table of Contents 

Introduction 3 

Statutory and Regulatory Authority 3 

DEET Chemical Facts 4 

Use and Usage Information 4 

Recent Actions 5 

Scientific Assessments 5 

Interim Registration Review Decision 9

Next Steps and Timeline 9 

Supporting documents for the DEET registration review case may be found in the docket EPAHQ-OPP-2012-0162 at http://www.regulations.gov. 
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INTRODUCTION 

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

Registration Review Decision for DEET and it discusses public comments received concerning 

the Proposed Interim Registration Review Decision. It 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). 

During the 60-day public comment period for the DEET Proposed Interim Registration 

Review Decision, which opened on June 4, 2014, and closed on August 4, 2014, the Agency 

received 3 submissions. Comments were submitted by the Center for Biological Diversity (CBD) 

and 2 anonymous public citizens. The comment from CBD agrees with the Agency’s finding 

regarding endangered species. The anonymous public comments describe a personal reaction to 

DEET and request clarification about whether DEET is defined as a pesticide. The public 

comments did not result in changes to the Agency’s DEET Proposed Interim Registration 

Review Decision. Public comments in their entirety are located in the docket, EPA-HQ-OPP2012-0162. 

DEET is a broad-spectrum insect repellent registered for use against biting flies, biting 

midges, black flies, chiggers, deer flies, fleas, gnats, horse flies, mosquitoes, no-see-ums, sand 

flies, stable flies, and ticks. DEET was developed by the United States (U.S.) Army in 1946 for 

use by military personnel in insect affected areas and was registered for use by the general public 

in 1957. DEET is currently registered for non-food and residential uses. There is also one 

registered product for use on horses. There are no registered food or agricultural uses. The 

Reregistration Eligibility Decision document (RED) for DEET was completed on April 13, 

1998.1

 For further information about DEET, additional documents can be found in EPA’s public 

docket (EPA-HQ-OPP-2012-0162) at www.regulations.gov. 

STATUTORY AND REGULATORY AUTHORITY 

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

program. All pesticides distributed or sold in the U.S. generally must 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 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 

www.epa.gov/oppsrrd1/registration_review/. 

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

FIFRA, and will review each registered pesticide every 15 years to determine whether it 

 

1

 Located at http://www.epa.gov/oppsrrd1/REDs/0002red.pdf 
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continues to meet the FIFRA standard for registration. The regulations governing registration 

review begin at 40 CFR 155.40. 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. 

DEET CHEMICAL FACTS 

PC code 080301 

Case Number 2 

CAS Number 134-62-3 

Year first registered 1957 

Pesticide Type Insect and acarid repellent 

Chemical class N, N-dialkylamides 

Reregistration Eligibility 

Decision (RED) 

September 1998 

Tolerance Reassessment 

Eligibility Decision 

(TRED) 

Not applicable. There are no registered DEET food/feed uses and 

no established tolerances for DEET. 

Cumulative group Not applicable. DEET has not been identified as a member of a 

cumulative group that shares a common mechanism of toxicity. 

40 CFR Citation There are no registered DEET food/feed uses and no established 

tolerances for DEET. 

Dual-use Conventional pesticidal uses only 

Non-pesticidal uses No non-pesticidal uses of DEET 

Pesticide Re-evaluation 

Division, Chemical 

Review Manager 

Susan Bartow, Bartow.Susan@epa.gov, (703) 603-0065 

Registration Division, 

Product Manager 

Richard Gebken, Gebken.Richard@epa.gov, (703) 305-6701 

USE AND USAGE INFORMATION 

Available data on DEET show that it accounted for the overwhelming majority of insect 

repellents used in the U.S. in 2005, 2009, and 2012 according to private market research surveys 

(Table 1.) About 30% of the U.S. population uses DEET annually as an insect repellent (EPA, 

1998). 

Table 1. DEET Usage in the U.S. 

Active Ingredient 2005 2009 2011 

Million lb Million lb Million lb 

DEET 7.7 6.8 9.2 

Source: Kline & Company, 2006, 2010, and 2012 
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The use of insect repellents such as DEET is intended to provide certain public health 

benefits. Application of DEET insect repellents to the skin and clothing is intended to help 

prevent bites from mosquitoes, ticks and other biting insects that may vector diseases such as 

Lyme disease, West Nile virus, malaria, yellow fever, dengue fever, and encephalitis. Please see 

the BEAD Chemical Profile for Registration Review: DEET (080301) in the registration review 

docket for more details. 

Summary of Use Broad-spectrum insect repellant registered for use on the human 

body, clothing, and on horses to repel biting flies, biting midges, 

black flies, chiggers, deer flies, fleas, gnats, horse flies, 

mosquitoes, no-see-ums, sand flies, stable flies, and ticks. 

Use Sites DEET is registered for use on horses (animal treatment); and 

human skin, hair, clothing, footwear, shoes and headgear (hats). 

Summary of Usage DEET accounts for the overwhelming majority of insect 

repellents used in the United States; approximately 30% of the 

U.S. population uses DEET annually as an insect repellent. 

Formulation Type(s) Formulations include microencapsulated, pressurized spray 

(aerosol), impregnated materials (e.g., towelettes, roll on), and 

ready-to-use solution (non-aerosol pump sprays, liquids, creams, 

lotions, and foams). A number of DEET products are also 

formulated with sunscreen. 

Application Method(s) DEET is generally applied using aerosol sprays, non-aerosol 

sprays, creams, lotions, roll-ons, foams, and towelettes. 

Technical Registrant(s) Clairant Corporation (8340) and Vertellus Performance Materials, 

Inc. (51147) 

No. of Registrations 122 active registrations 

Restricted Use No 

RECENT ACTIONS

There are no recent actions for DEET. 

SCIENTIFIC ASSESSMENTS

 A summary of the Agency’s human health and environmental fate and ecological risk 

assessments, DEET (N,N-Diethyl-meta-toluamide) – Revised Human Health Risk Assessment in 

Support of Registration Review (February 27, 2014) and Registration Review – Ecological Risk, 

Environmental Fate, and Endangered Species Assessment for N,N-Diethyl-meta-toluamide 

(DEET) (August 2, 2012), is presented below. For the detailed risk assessments, see the DEET 

public docket (EPA-HQ-OPP-2012-0162) accessed at www.regulations.gov. 

A. Human Health Assessment 

Hazard Characterization and Risk 

The toxicological database is considered adequate for characterizing hazard and assessing 

risk from DEET. No additional studies are anticipated to be needed for registration review. 
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Dietary Exposure Assessment 

There are no registered food/feed uses and existing use patterns are not expected to 

contaminate surface or ground water; thus, a dietary exposure assessment was not conducted. 

Food Tolerances 

There are no U.S. tolerances established for DEET because DEET is not registered for 

any food/feed uses. 

Residential and Occupational Exposure 

DEET is registered for use as an insect repellent, and for use on clothing or directly on 

the skin. There are also registered DEET-impregnated products, such as tablecloths. DEET 

products are available in multiple formulations, including aerosol sprays, creams, lotions, and in 

multiple concentrations. Exposures to DEET may occur from deliberate application to the skin 

and clothing of individuals. Human exposure from the repellent-use can be on the order of days 

or weeks or longer, depending on the individual user’s activity pattern and geographic area. 

Exposure is expected to be of short- and intermediate-term exposure duration; however, longterm exposures are possible for some individuals in some climates. 

Insect repellents are used by/on people of all ages. Adults are assumed to experience both 

dermal and inhalation handler exposures, as well as post-application dermal and, potentially, 

inhalation exposure. Adults are assumed to apply repellents to themselves or to others. 

Additionally, for aerosol repellents, individuals on whom the products are being applied can 

experience indirect inhalation exposure during the application. For children, post-application 

exposure consists of dermal, (potentially) inhalation, and hand-to-mouth exposure. An exposure 

assessment was previously prepared to support the DEET Registration Eligibility Decision 

(RED). Since no endpoints have been identified for DEET, a quantitative exposure and risk 

assessment for DEET products, including a residential exposure and risk assessment, is not 

anticipated to be needed at this time. There is no occupational exposure associated with DEET; 

therefore, an occupational risk assessment was not conducted (DEET (N,N-Diethyl-metatoluamide) – Revised Human Health Risk Assessment in Support of Registration Review 

(February 27, 2014)). 

Human Health Incidents 

The Office of Pesticide Programs (OPP) Incident Data System (IDS) was used to retrieve 

pesticide incident data on DEET. The IDS records incidents in one of two modules: Main IDS 

and Aggregate IDS. Main IDS contains incidents resulting in higher severity outcomes and 

provides more detail with regard to case specifics. Aggregate IDS contains incidents resulting in 

less severe human incidents (minor, unknown, or no effects outcomes). For the Main IDS, from 

January 1, 2007 to February 22, 2012, there were 387 exposures reported for single chemical 

only in the database (382 exposure classified as resulting in a moderate severity, 4 classified as 

major severity and 1 classified as an undetermined severity). In the Aggregate IDS, from January 

1, 2007 to February 22, 2012, there were 2,769 reported incidents involving DEET. DEET is not 

included in the Agricultural Health Study (AHS). 

Overall, there were a large number of incidents reported involving DEET; however, the 

number of incidents is relatively small when compared to the number of users. Most of the 

incidents reported to IDS involving DEET were classified as minor severity. Minor severity 
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means that a person alleged or exhibited some symptoms, but they were minimally traumatic, the 

symptoms resolved rapidly and usually involved skin, eye or respiratory irritation. Several high 

severity outcomes are reported in the IDS database. It is important to note, however, that there 

are a large number of users of DEET (approximately 104 million, based on the estimated use rate 

in 1984-19892

) and the number of incidents is relatively small in comparison. It also is unclear if 

there is a connection between DEET use and the incidents or if it is a coincidence. While 

incident information can be an important source of feedback to the Agency, reports of adverse 

health effects allegedly due to a specific pesticide exposure (i.e., an “incident”) are largely selfreported and therefore, generally speaking, neither exposure to a pesticide or reported symptom 

(or the connection between the two) is validated or otherwise confirmed. Typically, causation 

cannot be determined based on incident data (Revised DEET: Review of Human Incidents (June 

19, 2012) and DEET (N,N-Diethyl-meta-toluamide) – Revised Human Health Risk Assessment in 

Support of Registration Review (February 27, 2014)). 

B. Environmental Assessment 

Environmental Fate and Exposure 

 DEET is relatively stable, highly hygroscopic and sensitive to light. It is expected to be 

moderately mobile in the soil column. In surface waters and soil, DEET is expected to degrade at 

a moderate to rapid rate (the half-life of DEET is measured in days to weeks). The small amounts 

of DEET retained in air are subject to rapid photo-oxidation via hydroxy radical-mediated 

degradation with an estimated half-life between 10 to 15 hours. The bioaccumulation potential of 

DEET is low; it is neither a persistent, bioaccumulative toxicant nor a persistent organic 

pollutant. 

Based on the use characteristics and environmental fate properties of DEET, runoff, spray 

drift, leaching, and atmospheric deposition are unlikely to result in aquatic or terrestrial 

exposures to non-target plants and organisms. 

Ecological Risk Characterization 

The results of risk estimation for aquatic organisms indicate that registered uses of DEET 

will not result in level of concern (LOC) exceedances for acute risk to fish and invertebrates. 

Chronic risk quotients (RQs) were not calculated; however, given the large margin of safety 

observed for acute effects based on the most conservative exposure scenario, it is unlikely that 

chronic RQs would approach LOCs. Risks for aquatic plants are expected to be lower than 

LOCs, given the mode of action of DEET and the large margin of safety demonstrated for other 

aquatic organisms. 

Exposure in terrestrial habitats would be limited to human skin, clothing, and shoes, as 

well as horse skin and hair of horses that received DEET applications. Products formulated as 

lotions or impregnated wipes are applied directly to human skin. Many other product labels 

specify recommended spray distances of less than 10 inches from the intended application sites 

(human skin, clothing, and shoes, as well as horse skin and hair). The amount of DEET resulting 

 

2

 Veltri, J.C., Osimitz, T.G., Bradford, D.C., and Page, B.C. 1994. Retrospective analysis of calls to Poison Control 

Centers resulting from exposure to the insect repellent N,N-diethyl-m-toluamide (DEET) from 1985-1989. Clinical 

Toxicology, 32(1):1-16. 
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from human or horse application in the terrestrial environment (air, ground, plants, or non-treated 

animals) is inconsequential. As there is no complete exposure pathway under the currently 

registered uses, the Agency expects negligible risk to terrestrial organisms. 

Threatened and Endangered Species 

There is no reasonable expectation for any registered use of DEET to cause direct or 

indirect adverse effects to threatened and endangered species. No adverse modification of critical 

habitat is expected from the use of DEET. There are no aquatic LOC exceedances based on low 

environmental exposure and low toxicity to aquatic organisms. Conclusions regarding terrestrial 

organisms and plants are based on the lack of a complete exposure pathway. As discussed above, 

exposure is expected to be limited to human skin, clothing, and horses. Exposure to listed species 

is not expected because they would not likely come in direct contact with humans or domestic 

horses (i.e., the registered use sites). 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 (Registration 

Review – Ecological Risk, Environmental Fate, and Endangered Species Assessment for N,NDiethyl-meta-toluamide (DEET) (August 2, 2012)). 

Ecological Incidents 

There are no reported incidents for aquatic organisms or plants. A review of the 

following databases was completed on May 29, 2012: Ecological Incident Information System 

(EIIS), Aggregate Incident Reports database, Avian Monitoring Information System (AIMS), 

and the Contaminant Exposure and Effects – Terrestrial Vertebrate (CEE-TV). One incident was 

listed in the EIIS database and one incident was listed in the Aggregate Incident Report database. 

No additional incidents for DEET were identified in the AIMS or the CEE-TV databases. For 

additional discussion of the reported ecological incidents, see the Registration Review – 

Ecological Risk, Environmental Fate, and Endangered Species Assessment for N,N-Diethylmeta-toluamide (DEET).

C. 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 most recent registration decision for DEET, EPA 

reviewed these data and determined that a qualitative toxicity assessment is appropriate for 

DEET. However, as required by FFDCA section 408(p), DEET 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 
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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 

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. A second list of 

chemicals identified for EDSP screening was published on June 14, 20133

 and includes some 

pesticides scheduled for Registration Review and chemicals found in water. DEET was not 

included on either list. For further information on the status of the EDSP, the policies and 

procedures, the lists of chemicals, future lists, the test guidelines and the Tier 1 screening battery, 

please visit our website.4

 

 In the interim, EPA is making no human health or environmental safety findings 

associated with the EDSP screening of DEET. Before completing this Registration Review, the 

Agency will make an EDSP FFDCA section 408(p) determination. 

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 component of the DEET registration 

review case, the Agency has made the following interim 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. EPA has not identified any risks of concern to human health. Currently registered 

uses of DEET are not expected to result in adverse effects for listed and non-listed species, or 

critical habitat. As such, EPA concludes “no effect” for listed species and no adverse 

modification of designated critical habitat for all currently registered uses of DEET. 

NEXT STEPS AND TIMELINE 

A final decision on the DEET registration review case will occur after an EDSP FFDCA 

section 408(p) determination has been made. 

EPA created the following estimated timeline for the completion of the DEET Interim 

Registration Review Decision. 

 

3

 See http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPPT-2009-0477-0074 for the final second list of 

chemicals. 

4 http://www.epa.gov/endo/
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Registration Review for DEET – Interim Registration Review Timeline

Activities Estimated Date 

Opening the Docket and Combined Work Plan, Summary Document, and Interim Registration 

Review Decision 

Open Public Docket and Public Comment Period for Combined Work 

Plan, Summary Document, and Proposed Interim Registration Review 

Decision 

May 2014 –

Completed 

Close Public Comment Period July 2014 – 

Completed 

Interim Registration Review Decision and Begin Post-Decision 

Follow-up5

September 2014 – 

Completed 

Total (months) 4 

 

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 A final decision on the DEET registration review case, in accordance with 40 CFR Section155.158, will occur after 

an EDSP FFDCA section 408(p) determination has been made.