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Docket Number: EPA-HQ-OPP-2009-0637 

www.regulations.gov 

Deltamethrin Summary Document 

Registration Review: Initial Docket 

March 2010 

Case # 7414

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TABLE OF CONTENTS 

 Page # 

I. Preliminary Work Plan 4 

 

II. Fact Sheet 12 

 

___________________________________________________________ 

This Preliminary Work Plan (PWP) and Fact Sheet summarize the Environmental Protection 

Agency’s current position based on the following documents: 

1 “Environmental Fate and Ecological Risk Assessment Problem Formulation in Support of 

Registration Review for Deltamethrin,” USEPA, March 23, 2010. 

2 “Deltamethrin. Human Health Assessment Scoping Document in Support of Registration 

Review,” USEPA, February 17, 2010. 

3 “Updated Review of Deltamethrin Incident Reports,” USEPA, November 24, 2009. 

4 “EFED Section 3 Registration of Deltamethrin for use on Flax and Results from the 

Submission of a 6a2 Adverse Effects Daphnid Study,” USEPA, September 27, 2007 

5 “Tolerance Petition for Uses of Deltamethrin (PC Code 097805) on Field Corn, 

Sorghum, Soybeans, Sunflowers, Bulb Vegetables, Cucurbit Vegetables, Leafy 

Vegetables, Fruiting Vegetables, Carrots, Potatoes, Radishes, Artichokes, Cauliflower, 

Broccoli, Cabbage, Mustard Greens, Tree Nuts, Stone Fruits, and Pome Fruits (DP 

Barcode D262498) Incremental Ecological Effects Risk Assessment Due to the New 

Uses,” USEPA, August 6, 2002. 

6 “Ecological Effects Branch Review of Deltamethrin,” USEPA, January 17, 1994 

7 “Tier I Estimated Drinking Water Concentrations of Deltamethrin for the Use in the 

Human Health Risk Assessment: IR-4 Tolerance Petition for the Use of Deltamethrin on 

Flax,” USEPA, April 24, 2007. 

8 “Deltamethrin--Response to Tolerance Petition for Use on Flax,” USEPA, August 13, 

2009. 

9 “Screening Level Use Analysis for Deltamethrin,” USEPA, March 16, 2009. 

10 “Appendix A: Food/Feed & Non-Food/Non-Feed Uses Considered in Registration 

Review Work Planning—Deltamethrin,” April 13, 2009 

11 Wolansky, M. J., C. Gennings, and K. M. Crofton. “Relative Potencies for Acute Effects 

of Pyrethroids on Motor Function in Rats,” Tox. Sci. 89(1), pp. 271–277 (2006). 

Documents 1-10 may be found in the deltamethrin docket EPA-HQ-OPP-2009-0637 at 

www.regulations.gov. 
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I. PRELIMINARY WORK PLAN—Deltamethrin 

Introduction

The Food Quality Protection Act 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 www.epa.gov/oppsrrd1/registration_review/. 

The Agency is implementing the registration review program, and will review each 

registered pesticide every 15 years to determine whether it continues to meet the Federal 

Insecticide, Fungicide, and Rodenticide Act (FIFRA) standard for registration. Where 

assessments indicate risks above EPA’s level of concern (LOC), 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 deltamethrin. 

Deltamethrin is a pyrethroid registered for use on cotton, sorghum, artichokes, pears and a 

variety of vegetable, fruit, and tree nut crops for the control of a broad spectrum of pests 

including mites, ants, weevils, and beetles. It is also registered for use in residential and 

industrial applications for the control of cockroaches, pests of stored commodities, and other 

nuisance or destructive insects. A deltamethrin pet collar is registered for the control of fleas and 

ticks. Deltamethrin was first registered in the U.S. in 1994, and products containing deltamethrin 

were first marketed in the United States in 1997. 

Deltamethrin is also a metabolite of the pyrethroid pesticide tralomethrin, so that 

deltamethrin may occur as a result of applications of tralomethrin. In humans, tralomethrin is 

metabolized completely and rapidly into deltamethrin. As a result, EPA assumes that 

tralomethrin and deltamethrin have equivalent toxicity for human health risk assessment 

purposes. Tralomethrin breaks down more slowly in the environment than in the human body; 

the Agency may consider the compounds to have equivalent toxicity for mammals only. During 

registration review, the Agency will consider the appropriate method for addressing combined 

exposures from deltamethrin applied as a pesticide and deltamethrin originating from 

applications of tralomethrin. 
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The docket for the registration review of tralomethrin is opening at the same time as the 

deltamethrin docket. The tralomethrin docket can be accessed via www.regulations.gov under 

Docket ID OPP-2010-0116. 

Anticipated Risk Assessment and Data Needs 

The Agency expects to require data needed to update and revise the ecological risk 

assessment for deltamethrin (including an endangered species risk assessment) and the human 

health risk assessment. As noted above, the Agency will consider the appropriate method for 

addressing combined exposures from deltamethrin applied as a pesticide and deltamethrin 

originating from applications of tralomethrin. 

 

Ecological risk 

 The most recent assessment for deltamethrin was conducted in 2007, prompted by a 

proposal for a new tolerance for flax. The 2007 assessment references a 2002 assessment, and 

the 2002 assessment in turn references a 1994 assessment: 

 “EFED Section 3 Registration of Deltamethrin for use on Flax and Results from the 

Submission of a 6a2 Adverse Effects Daphnid Study,” USEPA, September 27, 2007. 

 “Tolerance Petition for Uses of Deltamethrin (PC Code 097805) on Field Corn, Sorghum, 

Soybeans, Sunflowers, Bulb Vegetables, Cucurbit Vegetables, Leafy Vegetables, Fruiting 

Vegetables, Carrots, Potatoes, Radishes, Artichokes, Cauliflower, Broccoli, Cabbage, 

Mustard Greens, Tree Nuts, Stone Fruits, and Pome Fruits (DP Barcode D262498) 

Incremental Ecological Effects Risk Assessment Due to the New Uses,” USEPA, August 

6, 2002. 

 “Ecological Effects Branch Review of Deltamethrin,” USEPA, January 17, 1994.

The Agency has not conducted a risk assessment that supports a complete endangered species 

determination for deltamethrin. The ecological risk assessment planned during registration review 

will allow the Agency to determine whether deltamethrin’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 and/or National 

Marine Fisheries Service (the Services), as appropriate. 

The Agency anticipates requiring the following data in order to conduct a complete 

ecological risk assessment, including an endangered species assessment, for deltamethrin:

• Guideline # 835.4300 Aerobic Aquatic Metabolism 

• Guideline # 835.4400 Anaerobic Aquatic Metabolism 

• Guideline #s 835.6100 & 6200 Environmental Chemistry Methods and Independent 

Laboratory Validations for Soil, Water and Sediment 

• Guideline # 850.2100 Passerine Acute Avian Oral 

• Guideline # 850.1400 Fish Early Life Stage (saltwater) 

• Guideline # 850.1500 Fish Life Cycle (saltwater) 
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• Guideline # 850.1350 Aquatic Invertebrate Life-Cycle (saltwater) 

• Guideline # 850.1790 Whole sediment, chronic invertebrates freshwater and marine 

• Guideline # 850.4150 & 4250 Vegetative vigor and Seedling emergence, Tier I/ Tier II 

• Guideline # 850.4400 Aquatic Vascular Plant Growth-Lemna spp. Tiers I/II 

• Guideline # 850.5400 Algal toxicity test, Tier I/II 

Please refer to the document “Environmental Fate and Ecological Risk Assessment Problem 

Formulation in Support of Registration Review for Deltamethrin, March 23, 2010 for a more 

detailed discussion of anticipated ecological risk assessment data needs.

Human Health Risk 

The most recent assessment for deltamethrin was conducted in 2009, prompted by a proposal 

for a new tolerance for flax. The assessment is documented in: 

 “Tier I Estimated Drinking Water Concentrations of Deltamethrin for the Use in the 

Human Health Risk Assessment: IR-4 Tolerance Petition for the Use of Deltamethrin on 

Flax,” USEPA, April 24, 2007. 

 “Deltamethrin--Response to Tolerance Petition for Use on Flax,” USEPA, August 13, 

2009. 

Additional analyses are discussed in: 

 “Deltamethrin--Human Health Assessment Scoping Document in Support of Registration 

Review,” USEPA, February 17, 2010. 

This latter document includes an aggregate risk assessment that incorporates residential uses 

not covered by the 2009 assessment, and documents some aggregate risk estimates of concern. 

The Agency believes that a refined assessment utilizing additional data and new assessment 

methodologies may reduce some of these risk estimates relative to conservative, default data and 

methodologies. For some residential uses with very low MOEs, refinement of the risk 

assessment is not likely to reduce risk estimates below levels of concern, and the Agency is 

currently working with affected registrants to mitigate the risks. 

• The existing residue chemistry database for deltamethrin is adequate for risk assessment 

purposes. 

• The Agency is investigating the need for additional experimentation, regarding the 

pharmacokinetics of pyrethroids and the potential for increased susceptibility of young 

organisms. The Agency will revisit its decision on the need for an FQPA or other 

database uncertainty/safety factors following receipt of the toxicity data the Agency 

expects to require, and following a final determination of the potential for increased 

susceptibility of infants and children to pyrethroid pesticides based on the results of all 

available data. 

• Aside from the potential outcome of the research described above, the toxicology 
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database for deltamethrin is essentially complete, with the exception of the 

immunotoxicity data. The Agency expects to require an immunotoxicity study 

(Guideline # 870.7800). 

• The Agency anticipates conducting a new dietary risk assessment in registration review 

to incorporate updated drinking water estimates, information on dietary consumption, and 

usage information. In order to better understand post-application residential exposure, 

the Agency expects to require data on the transfer of deltamethrin residues from pets 

wearing deltamethrin flea collars to humans. The Agency anticipates developing a 

refined aggregate assessment for combined exposures from food, drinking water, and 

residential exposures. 

• The Agency anticipates conducting a new occupational risk assessment in registration 

review, which would utilize any new and relevant toxicological endpoints, exposure data, 

policies, and incident data as appropriate. 

• Deltamethrin is an animal and environmental metabolite of another pyrethroid 

insecticide, tralomethrin. The docket for the registration review of tralomethrin is 

opening at the same time as the deltamethrin docket. In recent assessments, the human 

toxicology endpoint selected for tralomethrin is derived from the same study as that used 

in assessing the risks associated with deltamethrin use, and the dietary risk assessment for 

deltamethrin accounted for tralomethrin use. The registration review docket for 

tralomethrin can be accessed via www.regulations.gov under Docket ID OPP- 2010-

0116. 

• In 1997, tolerances for tralomethrin and deltamethrin were reassessed in response to a 

general policy change in which time limitations for tolerances were deleted. For this 

FQPA reassessment, exposures associated with the use of both tralomethrin and 

deltamethrin were combined. The basis for this approach was that tralomethrin is rapidly 

metabolized by animals to deltamethrin (as a result of debromination) and the toxicology 

profiles of deltamethrin and tralomethrin are virtually identical. 

• The Agency is currently working to develop an approach for addressing human health 

risks from combined exposures to deltamethrin applied as a pesticide and deltamethrin 

residues originating from applications of tralomethrin. 

• Deltamethrin is a member of the pyrethroid class of insecticides. This class also includes 

permethrin, cypermethrin, cyfluthrin, tau-fluvalinate, bifenthrin, fenpropathrin, and 

lambda-cyhalothrin, among others. EPA developed a draft science policy document on 

the proposed common mechanism of toxicity for naturally-occurring pyrethrins and 

synthetic pyrethroids (Draft Science Policy Paper: Common Mechanism Grouping for the 

Pyrethrins and Synthetic Pyrethroid Pesticides, May 19, 2009, available in the docket at 

http://www.regulations.gov/search/Regs/home.html#documentDetail?R=09000064809a6

2df ). The FIFRA Scientific Advisory Panel (SAP) supported the draft science policy 
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(Minutes from the SAP meeting on the Evaluation of the Common Mechanism of Action of 

the Pyrethroid Pesticides, September 9, 2009, available in the docket at 

http://www.regulations.gov/search/Regs/home.html#documentDetail?R=0900006480a1f8d7)

. EPA will finalize the policy document on the pyrethroid common mechanism of toxicity 

taking into account the recommendations of the SAP. Pesticides with a common mechanism 

of toxicity are subject to cumulative risk assessment under the FQPA. Research is on-going 

by EPA’s Office of Research and Development (ORD) to make improvements to the 

Stochastic Human Exposure and Dose Simulation (SHEDS) probabilistic exposure model, 

which are important for the cumulative risk assessment. EPA ORD is also developing 

physiologically-based pharmacokinetic models for several pyrethroids. The status of both of 

these research modeling efforts will be reviewed by the FIFRA SAP in July, 2010. For 

information regarding EPA’s efforts to evaluate the risk from pyrethroids, see 

http://www.epa.gov/oppsrrd1/reevaluation/pyrethroids-pyrethrins.html. 

• During registration review, the tolerance expression for deltamethrin in 40 CFR § 

180.435 will be reviewed to ensure that it appropriately covers the metabolites and 

degradates of deltamethrin and that it specifies the residues to be measured for each 

commodity. Any proposed revisions would be to the chemical description rather than the 

individual tolerance levels. 

The Agency anticipates needing the following data in order to conduct a complete human 

health risk assessment for deltamethrin: 

• Guideline # 870.7800 Immunotoxicity 

• Special Study, Pet Collar Residue Transfer 

Please refer to the document “Deltamethrin. Human Health Assessment Scoping Document 

in Support of Registration Review,” February 17, 2010 for a more detailed discussion of human 

health risk estimates and anticipated human health risk assessment data needs. 

Other Data Needs 

• Guideline # 830.7050 UV/Visible Light Absorption – this study is a new data 

requirement under 40 CFR part 158 (Product Chemistry Data Requirements) for 

registration of a pesticide (food and non-food uses). The Agency anticipates requiring 

this study to obtain basic information about the compound’s identity/composition and the 

wavelengths at which the compound may be susceptible to photochemical degradation.

Endocrine Disruptor Screening Program

As required under FFDCA section 408(p), EPA has developed the Endocrine Disruptor 

Screening Program (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 
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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 quantitative relationship between the dose and the E, A, or T effect.

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. 

This list of chemicals was selected based on the potential for human exposure through pathways 

such as food and water, residential activity, and certain post-application agricultural scenarios. 

This list should not be construed as a list of known or likely endocrine disruptors. 

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

screened under the EDSP. Under FFDCA sec. 408(p) the Agency must screen all pesticide 

chemicals. Accordingly, EPA anticipates issuing future EDSP orders/data call-ins for all 

Registration Review cases, including those for which EPA has already opened a Registration 

Review docket for a pesticide active ingredient. 

For further information on the status of the EDSP, the policies and procedures, the list of 67 

chemicals, the test guidelines and the Tier 1 screening battery, please visit the website: 

http://www.epa.gov/endo/. 

Timeline 

The projected timeline for the deltamethrin registration review appears in the table below. 

Projected Deltamethrin Registration Review Timeline 

Activities Estimated Date 

Opening the docket 

Open Docket and Public Comment Period 2010 – March 

Close Public Comment 2010 – May 

Case Development 

Final Work Plan 2010 – August 

Issue DCI 2011 – April - June 

Data Submission 2013 – April - June 

Open Public Comment Period for Preliminary Risk Assessments 2014 – Oct. – Dec. 

Close Public Comment Period 2015 – Jan. - March 

Registration Review Decision 

Open Public Comment Period for Proposed Registration Review 

Decision 

 2015 – April - June 

Close Public Comment Period 2015 – July – Sept. 

Final Registration Review Decision and Begin Post-Decision 

Follow-up 

 2016 

Total (years)* 6 

* An assessment of the potential cumulative risk from the pyrethroid class of insecticides may impact this time 
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estimate.

Guidance for Commenters; Solicitation of Information 

The public is invited to comment on EPA’s preliminary registration review work plan and 

rationale. The Agency will carefully consider all comments, and any additional information that 

is provided in a timely manner, prior to issuing a final work plan for the deltamethrin registration 

review 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. 

Water Quality 

Deltamethrin is not identified as a cause of impairment for any water bodies listed as 

impaired under section 303(d) of the Clean Water Act, based on information provided at 

http://iaspub.epa.gov/tmdl_waters10/attains_nation_cy.cause_detail_303d?p_cause_group_id=88

5. However, the pyrethroids as a group have been identified as a cause for impairment for three 

water bodies in Central Valley, CA: Del Puerto Creek, Ingram Creek Site (confluence with 

Hospital Creek to Hwy 33 crossing) and a second Ingram Creek Site (confluence with San 

Joaquin River to confluence with Hospital Creek). Nonetheless, no Total Maximum Daily Loads 

(TMDL) have been developed for deltamethrin, based on information provided at 

http://iaspub.epa.gov/tmdl_waters10/attains_nation.tmdl_pollutant_detail?p_pollutant_group_id

=885&p_pollutant_group_name=PESTICIDES. More information on impaired water bodies and 

TMDLs can be found at http://www.epa.gov/owow/tmdl/. 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 Process (see: 

http://www.epa.gov/oppsrrd1/registration_review/water_quality_sop.htm), in order to ensure 

they can be used quantitatively or qualitatively in pesticide risk assessments. 

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, 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 deltamethrin 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. 
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Additional Information

 

Stakeholders are asked to provide additional information that will assist the Agency in 

refining its assessments for deltamethrin, such as the following information: 

1. Deltamethrin human, domestic animal, or ecological incidents not already reported to the 

Agency. 

2. Information on or confirmation of the following use parameters: 

 Sites of application 

 Formulation type 

 Application methods and equipment 

 Maximum application rates expressed as mass ai per unit area 

 Typical application rates 

Factors affecting application rate, e.g., weather, disease pressure, fresh/processed 

commodity 

 Application intervals, factors affecting frequency of application 

 Maximum number of applications per year (or season, as appropriate). 

 

3. Use or potential use distribution (e.g., geographical distribution of uses, areas of greatest use). 

4. General use history. 

5. Median and 90th percentile reported use rates from usage data – national/state/county. 

6. Application timing (date of first application and typical application intervals) by use – 

national, state, and county. 

7. Sub-county use site data. 

8. Usage data for non-agricultural uses (e.g., residential uses, paints and paint additives, building 

materials, restaurants, buses, railcars, trucks, tire piles, mausoleums, warehouses, and food 

handling establishments). 

9. Directly acquired county-level usage data (not derived from state level data). 

Maximum reported use rate from usage data – county 

Median and 90th percentile number of applications – county 

Total pounds per year – county 

Year the pesticide was last used in the county/sub-county area (if no longer used), and/or 

Years in which the pesticide was applied in the county/sub-county area. 

10. State, local, or other geographic use restrictions. 

11. Any adverse effects in honey bees associated with the use of deltamethrin products. 

12. Co-formulation or tank-mixing of deltamethrin and other pesticides (especially other 
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pyrethroids)—is deltamethrin typically applied with other pesticides? 

13. Mode of action for flea collars, that is, how deltamethrin spreads over the body of the pet or 

how fleas otherwise come into contact with deltamethrin from the flea collar. 

14. Confirmation of the use of deltamethrin in plastic foam panels; use patterns and potential 

exposures to deltamethrin used in these panels, e.g., where such panels are used, who installs 

them (professionals or homeowners), how many could an individual typically install in a 

working day/in a year, what is the potential for exposure for residents or occupants of buildings 

where they are installed (are they open to the living space, or behind wall paneling, for example). 

15. Use patterns and potential exposures to deltamethrin for sites on which the Agency lacks 

such information, including: food storage facilities, dairies, food processing facilities, eating 

establishments, food markets, grocery stores, bathrooms, garbage cans, commercial animal 

kennels, ships/boats/automobiles/taxis/limousines/recreational vehicles, tires, 

bedding/mattresses, carpets, drainage systems, hospitals, morgues/mortuaries, caskets, and 

cadavers. 

Next Steps

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

comments that have been submitted in a timely manner, and then issue a Final Work Plan for this 

pesticide. The Agency expects to issue a Final Work Plan for deltamethrin in August 2010.
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II. FACT SHEET: Deltamethrin Registration Review 

Background Information for Deltamethrin

 Registration review case number: 7414 

 Pesticide Chemical (PC) Code: 097805 

 Chemical Abstracts Service (CAS) number: 529 18-63-5 

 Other names: (S-cyano(3-phenoxyphenyl)methyl (1 R,3R)-3-(2,2-dibromoethenyl)-2,2-

dimethylcyclopropanecarboxylate, (S-α-cyano-3-phenoxybenzyl (1 R)-cis-3-(2,2-

dibromovinyl)-2,2-dimethylcyclopropanecarboxylate;

 The deltamethrin active ingredient is composed of three isomers, with the cis- isomer 

making up about 99% of the total. 

 Chemical Class: Deltamethrin is a Type II pyrethroid. Pyrethroids are grouped by 

structure and mode of action into several different types. Cypermethrin, cyfluthrin, 

cyphenothrin, esfenvalerate, fluvalinate, and tralomethrin are also Type II pyrethroids.

 Deltamethrin was first registered in the U.S. in 1994. 

 Four registrants hold a total of eight manufacturing-use deltamethrin registrations. Over 

30 formulators hold a total of more than 140 end-use registrations. 

 There are no FIFRA Special Local Need 24(c) products registered with the Agency. 

Contact information

 Pesticide Re-evaluation Division: Jill Bloom; bloom.jill@epa.gov

 Registration Division: Olga Odiott; odiott.olga@epa.gov 

Use & Usage Information

The Agency has conducted a Screening Level Usage Analysis (SLUA) for deltamethrin and 

developed a listing of use parameters for the use sites of deltamethrin. The SLUA and 

“Appendix A” (as the listing of use parameters is known) are available in the deltamethrin 

docket.

 Deltamethrin is a pyrethroid acaricide/insecticide registered to control a variety of pests, 

including mites, ants, weevils, and beetles on many sites, including cotton, sorghum, 

artichokes, pears, and a variety of vegetable, fruit, and tree nut crops. It is also 

registered for use both indoors and outdoors in a number of residential and institutional 

settings for control of bedbugs, cockroaches, silverfish, mosquitoes, wasps, other flying 

and crawling insects, fleas, and ticks. Non-crop, non-residential uses include 

restaurants, buses, railcars, trucks, tire piles, mausoleums, warehouses, and food 

handling establishments. 

 About 6,000 lbs. and 1,000 lbs. of deltamethrin ai /year are used on cotton and sorghum, 

respectively. For each of the remaining agricultural use sites, less than 500 lbs. in used 

annually. Between 15 and 20% of the artichoke crop is treated with deltamethrin. For 

the other agricultural sites, 5% or less of the crop is treated. The Agency does not have 
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estimates for non-agricultural usage. 

 End-use products may be formulated as ready-to-use liquid sprays and pressurized 

liquids, paint additives and paint, granulars, dusts, wettable powders, and flowable and 

emulsifiable concentrates. 

 Rates of application vary by use site. Agricultural applications are generally in the range 

of 0.005 to 0.130 lb ai/A/application. The flea and tick collars for dogs contain 4% active 

ingredient by weight and the user is directed to apply a new collar every six months. 

 Application methods include drench, crack and crevice, spot treatment, and broadcast 

spraying. Application equipment includes aerosol can, spreader, aerial, chemigation, and 

a variety of handheld equipment (e.g., sprinkler can, backpack, low pressure handwand). 

Paint formulated with deltamethrin may be applied by brushing, rolling, dipping, or 

airless sprayer. 

 Number of applications is frequently not stated on labels. 

 

Recent and Related Actions

 A recent petition for establishing tolerances for deltamethrin on flax has been withdrawn. 

The Agency sought public comment on an application for a proposed new use of 

deltamethrin on flax for one month beginning on October 26, 2009 (FRL–8794–2). No 

comments were received. The application was subsequently withdrawn. 

 Deltamethrin is a mammalian and environmental metabolite of another pyrethroid 

insecticide, tralomethrin. The docket for the registration review of tralomethrin is 

opening at the same time as the deltamethrin docket. The registration review docket for 

tralomethrin can be accessed via www.regulations.gov under Docket ID OPP- 2010-

0116. 

Ecological Risk Assessment Status 

Refer to the supporting documents, including “Environmental Fate and Ecological Risk 

Assessment Problem Formulation in Support of Registration Review for Deltamethrin,” USEPA, 

March 23, 2010, for a discussion of the most current ecological risk and endangered species 

assessments. 

Deltamethrin is “practically nontoxic” on an acute basis to the avian species that have been 

tested; no chronic effects were observed in bobwhite quail and mallard duck. Deltamethrin is 

“highly toxic” to honey bees on an acute basis. Deltamethrin is “very highly toxic” to the 

freshwater and marine/estuarine fish and invertebrate species that have been tested, and 

impairment of growth and reduced reproductive success have been observed in chronic studies 

on the freshwater species. In the field, deltamethrin tends to bind to soil particles and organic 

matter, and it is not expected to leach into groundwater. Deltamethrin may reach aquatic 

resources through spray drift or erosion. It is moderately to highly persistent in the terrestrial 
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environment and has the potential to persist in aquatic environments, particularly in the 

sediment. In laboratory studies, deltamethrin exhibited a potential for bioaccumulation in fish. 

The incremental risk associated with the proposed use on flax was based on an earlier assessment 

of pome fruit (apple, pear, etc.) in which the Agency determined there were chronic risks of 

concern for fish and aquatic invertebrates, specially those living in or near the benthos. 

Human Health Risk Assessment Status

Please refer to the supporting documents, including “Deltamethrin. Human Health 

Assessment Scoping Document in Support of Registration Review,” USEPA, February 17, 2010, 

for a discussion of the most recent human health risk assessment. 

 At the current time, EPA has selected the toxicological endpoint for the human health risk 

assessment of deltamethrin based on an acute exposure study documented in the open literature: 

Wolansky, M. J., C. Gennings, and K. M. Crofton. “Relative Potencies for Acute Effects of 

Pyrethroids on Motor Function in Rats,” Tox. Sci. 89(1), pp. 271–277 (2006). 

 In the Wolansky study, decreased motor activity was observed in rats receiving oral doses of 

deltamethrin. The NOAEL was calculated at 1 mg/kg/day and is applicable for all exposure 

durations because deltamethrin is rapidly eliminated from the body, precluding bioaccumulation, 

and no additional toxicity would be expected with increased dosing duration. A traditional 

uncertainty factor of 100x (10x for interspecies extrapolation and 10x for intraspecies variation) 

was applied. The Wolansky study utilized adult rats, but other studies from the open literature 

are indicative of increased susceptibility in young animals based on toxicokinetic differences 

between young and adult animals. Because of this evidence of increased susceptibility, the 10x 

FQPA Safety Factor was retained for population subgroups comprised of infants and children. 

Therefore, the overall uncertainty factor is 1000x for all deltamethrin exposure scenarios 

involving these subgroups, and 100x for all other populations. 

Cumulative assessment 

Deltamethrin is a member of the pyrethroid class of insecticides. Other pyrethroids include 

permethrin, cypermethrin, cyfluthrin, tau-fluvalinate, bifenthrin, fenpropathrin, and lambdacyhalothrin. EPA has developed a draft science policy document on the proposed common 

mechanism of toxicity for naturally-occurring pyrethrins and synthetic pyrethroids, which was 

supported by the FIFRA Scientific Advisory Panel (SAP). Upon finalization of this science 

policy, the pyrethroids will be subject to a cumulative risk assessment under the FQPA. 

Incident Reports 

 Examination of 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 (SENSOR) database revealed a 

moderately large numbers of case reports in humans associated with the use of 

deltamethrin. Most of these incidents were of low severity, and no patterns or trends 

were discerned. The Agency will continue to monitor the incident information and if a 
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concern is triggered, additional analysis will be included in the registration review risk 

assessment. 

 The Ecological Incident Information System (EIIS, version 2.1) maintained by the Office of 

Pesticide Programs, and the Avian Monitoring Information System (AIMS), maintained by 

the American Bird Conservancy, show one reported ecological incident associated with the 

use of deltamethrin. The report for this incident describes a fish kill of approximately 350 

bullhead fish (Ameirurus sp.). This incident resulted from a golf course application of 

three chemicals: imidacloprid, thiophanate-methyl and deltamethrin. The incident report 

identified deltamethrin as the probable cause of the fish kill. 

Tolerances and International Harmonization

 Tolerances for deltamethrin are located at 40 CFR § 180.435; they can be accessed 

electronically in Volume 40 of the eCFR by searching for “deltamethrin” at 

http://ecfr.gpoaccess.gov/cgi/t/text/textidx?sid=f7b808a2bc0a1bee945ff568ee85707e&c=ecfr&page=simple

 There are many Codex MRLs for deltamethrin. The MRLs can be found by searching for 

“deltamethrin” at the International Portal on Food Safety, animal & Plant Health at 

http://www.ipfsaph.org/En/default.jsp. 

Data Call-In Status 

 Currently, there are no outstanding, previously required data for deltamethrin. 

Labels

Images of the labels of registered deltamethrin products can be obtained from the Pesticide 

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