Docket Number EPA-HQ-OPP-2010-0116 

www.regulations.gov

Tralomethrin Summary Document 

Registration Review: Initial Docket 

March 2010 

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TABLE OF CONTENTS 

 Page # 

I. Preliminary Work Plan (PWP) 4 

II. Fact Sheet 14 

 

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 Ecological Risk and 

Environmental Fate, Endangered Species, and Drinking water Assessments for Tralomethrin 

(March 23, 2010) 

2. Tralomethrin. Human Health Assessment Scoping Document in Support of Registration

Review (February 24, 2010) 

3. PRD Appendix A: Food/Feed & Non-Food/Non-Feed Uses Considered in Registration 

Review Work Planning – Tralomethrin (121501 (December 22, 2008 

4. Screening Level Estimates of Agricultural Uses of Tralomethrin (121501) (April 7, 2009) 

5. Updated Review of Tralomethrin Incident Reports, June 30, 2009 

All supporting documents for the registration review of Tralomethrin are located in docket EPA-HQOPP-2010-0116 at www.regulations.gov. 
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I. PRELIMINARY WORK PLAN – Tralomethrin 

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), 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 tralomethrin. 

Tralomethrin is a broad-spectrum Type II systemic pyrethroid ester insecticide used in a 

variety of residential and commercial settings, and on a small number of agricultural crops including 

broccoli, cauliflower, cotton, lettuce, peanuts, and sunflowers. Since tralomethrin was first 

registered in 1985, it was not subject to a Reregistration Eligibility Decision (RED). In 1997, EPA 

reassessed tolerances of tralomethrin as required by FQPA. (62 Fed. Reg. 62,993, November 26, 

1997). 

 Tralomethrin breaks down in the environment and the human body into another active 

pesticide ingredient, deltamethrin. In humans, tralomethrin is metabolized completely and 

immediately into deltamethrin. As a result, EPA assumes that tralomethrin and deltamethrin have 

equivalent toxicity for human health risk assessment purposes. However, tralomethrin breaks down 

more slowly in the environment than in the human body so equivalent toxicity cannot be assumed 

for organisms other than mammals. Therefore, tralomethrin and deltamethrin residues resulting 

from tralomethrin use will be considered independently in the ecological risk assessment. 

Deltamethrin use is being assessed individually in registration review (case #7414; docket ID 

OPP-2010-0116). During registration review, the Agency will consider the appropriate method for 
5

addressing combined exposures from deltamethrin applied as a pesticide and deltamethrin 

originating from applications of tralomethrin. 

In 2009, in response to a proposed new use on flax, EPA conducted a dietary risk assessment 

that evaluated dietary exposure from the combined usage of deltamethrin and tralomethrin. This risk 

assessment showed that the combined exposures from the existing uses of tralomethrin and 

deltamethrin result in acute dietary risk estimates of concern for infants and children. Accordingly, 

the new deltamethrin use was not granted. EPA is currently refining this dietary risk assessment 

with updated usage and monitoring data, and expects that these refinements will reduce dietary risk 

estimates below levels of concern. 

Anticipated Risk Assessment and Data Needs

The Agency anticipates conducting a comprehensive ecological risk assessment, including an 

endangered species risk assessment, for all uses of tralomethrin. The Agency also anticipates 

conducting dietary, residential, occupational, and aggregate human exposure risk assessments. 

 

Ecological Risk: 

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

species determination for tralomethrin. 

• The ecological risk assessment planned during registration review will allow the Agency to 

examine whether tralomethrin’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. 

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

risk assessment, including an endangered species assessment for tralomethrin:

Tralomethrin

• GDLN 835.1230 or 825.1240 – Leaching and adsorption/desorption1

• GDLN 835.2120 – Hydrolysis 

• GDLN 835.2240 – Photodegradation in Water 

• GDLN 835.2410 – Photodegradation on Soil 

• GDLN 835.4100 – Aerobic Soil Metabolism 

• GDLN 835.4300 – Aerobic Aquatic Metabolism 

 

1

 If the registrant can clarify deficiencies observed in a previously submitted study (MRID 44814506), a leaching 

adsorption/desorption study will not be required. See Registration Review – Preliminary Problem Formulation for 

Ecological Risk and Environmental Fate, Endangered Species, and Drinking water Assessments for Tralomethrin

(March 23, 2010).
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• GDLN 835.4400 – Anaerobic Aquatic Metabolism 

• GDLN 835.6100 (footnote 7) – Environmental Chemistry Methods – soil 

• GDLN 835.6200 (footnote 7) – Environmental Chemistry Methods – water 

• GDLN 835.6200 (footnote 7) – Environmental Chemistry Methods – sediment 

• GDLN 850.1025 – Acute Toxicity Estuarine and Marine Organisms (oyster) (typical enduse product) 

• GDLN 850.1035 – Acute Toxicity Estuarine and Marine Organisms (mysid) (typical enduse product) 

• GDLN 850.1075 – Acute Toxicity Estuarine and Marine Organisms (fish) (typical enduse product) 

• GDLN 850.1400 – Fish Early-Life Stage (estuarine/marine) 

• GDLN 850.1500 – Fish Life-Cycle (estuarine/marine) 

• GDLN 850.2100 –Avian Oral Toxicity (passerine species) 

• GDLNs 850.4100 & 850.4150 – Seedling Emergence & Vegetative Vigor (Tier 1 & Tier 

2)2

• GDLNs 850.4400 & 850.5400 – Aquatic Plant Growth (algal and aquatic vascular plant 

toxicity) (Tier I and Tier II)3

• Special Study – Whole Sediment: Chronic Invertebrates (estuarine/marine) (Leptocheirus 

plumulosus)

• Special Study – Whole Sediment: Chronic Invertebrates (freshwater) (Hyalella azteca

and Chironomus dilutus) 

Deltamethrin

• GDLN 835.4300 – Aerobic Aquatic Metabolism 

• GDLN 835.4400 – Anaerobic Aquatic Metabolism 

• GDLN 835.6100 (footnote 7) – Environmental Chemistry Methods – soil 

• GDLN 835.6200 (footnote 7) – Environmental Chemistry Methods – water 

• GDLN 835.6200 (footnote 7) – Environmental Chemistry Methods – sediment 

• GDLN 850.1350 – Aquatic Invertebrate Life Cycle (estuarine/marine) 

• GDLN 850.1400 – Fish Early-Life Stage (estuarine/marine) 

• GDLN 850.1500 – Fish Life-Cycle (estuarine/marine) 

• GDLN 850.2100 –Avian Oral Toxicity (passerine species) 

• GDLNs 850.4100 & 850.4150 – Seedling Emergence & Vegetative Vigor (Tier 1 & Tier 

2)4

 

2

 A Tier II is only required if a tested terrestrial species exhibits a 25% or greater detrimental effect in the Tier I study. 

When Tier II testing is required, the test species should be the species that showed detrimental effects in the Tier I 

testing. 

3 A Tier II is only required if the tested aquatic species exhibits a 50% or greater detrimental effect in the Tier I study. 

When Tier II testing is required, the test species should be the species that showed detrimental effects in the tier I testing. 4

 A Tier II is only required if a tested terrestrial species exhibits a 25% or greater detrimental effect in the Tier I study. 

When Tier II testing is required, the test species should be the species that showed detrimental effects in the Tier I 

testing. 
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• GDLNs 850.4400 & 850.5400 – Aquatic Plant Growth (algal and aquatic vascular plant 

toxicity) (Tier I and Tier II)5

• Special Study – Whole Sediment: Chronic Invertebrates (freshwater) (Hyalella azteca

and Chironomus dilutus) 

• Special Study – Whole Sediment: Chronic Invertebrates (estuarine/marine) (Leptocheirus 

plumulosus)

• Please refer to Registration Review – Preliminary Problem Formulation for Ecological Risk 

and Environmental Fate, Endangered Species, and Drinking water Assessments for 

Tralomethrin (March 23, 2010), for a more detailed discussion of the anticipated ecological 

risk assessment needs.

Human Health Risk: 

• Tralomethrin is rapidly and completely metabolized in the human body to another pesticide 

active ingredient deltamethrin. Therefore, human health risk assessments for tralomethrin 

and deltamethrin are based on a combined tralomethrin/deltamethrin toxicity database. 

• The most recent risk assessment that evaluated exposure to tralomethrin use was a 2009 

dietary assessment completed for the proposed new use of deltamethrin on flax. This 

assessment evaluated the dietary exposure from the combined usage of tralomethrin and 

deltamethrin. Tralomethrin and deltamethrin were also combined when tolerances were 

reassessed pursuant to FQPA in 1997. 

• Based on the Agency’s review of existing pyrethroid data, EPA has come to the conclusion 

that the DNT is not a particularly sensitive study for comparing the sensitivity of young and 

adult animals to pyrethroids. As an alternative to the generation and submission of a new 

DNT study, the tralomethrin registrants may instead choose to cite the previously submitted 

DNT study for deltamethrin. The Agency is also investigating the need for additional 

experimentation, specific to the mode of action and pharmacokinetic characteristics of 

pyrethroids, to evaluate the potential for increased susceptibility of young organisms. A 

meeting of FIFRA Scientific Advisory Panel (SAP) is planned for July 2010. EPA is 

currently soliciting proposals for study design and protocols. For more information on the 

pyrethroid DNT requirement, see http://www.epa.gov/oppsrrd1/reevaluation/pyrethroidspyrethrins.html . 

• In 2009, EPA retained a 10X FQPA safety factor for deltamethrin based on recent literature 

studies that showed children have a diminished capacity to detoxify deltamethrin relative to 

adults. The Agency may revise its FQPA factor following receipt of required toxicity data 

and following a final determination of the potential for increased susceptibility of infants and 

 

5 A Tier II is only required if the tested aquatic species exhibits a 50% or greater detrimental effect in the Tier I study. 

When Tier II testing is required, the test species should be the species that showed detrimental effects in the tier I testing.
8

children to pyrethroid pesticides based on the results of all available data. 

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

purposes. 

• The Agency anticipates conducting a new dietary risk assessment evaluating combined 

residues from tralomethrin and deltamethrin use in registration review. This assessment will 

incorporate updated drinking water estimates, consumption information, usage information, 

and monitoring data. 

• When EPA reassessed tralomethrin tolerances in 1997, it combined residential exposure of 

tralomethrin and deltamethrin for risk assessment purposes. The basis for this approach was 

that tralomethrin is rapidly metabolized by animals to deltamethrin (as a result of 

debromination), the toxicology profiles of deltamethrin and tralomethrin are virtually 

identical. At the time, the“flea infestation control” scenario was thought to represent 

plausible but worst-case residential exposure from deltamethrin and tralomethrin use. 

However, in registration review, the Agency anticipates conducting a residential risk 

assessment specific to tralomethrin use patterns. 

• The Agency anticipates conducting an aggregate assessment for tralomethrin in registration 

review to incorporate the planned residential exposure assessment and an updated dietary risk 

assessment. 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. 

• The Agency has not previously conducted an occupational handler or an occupational postapplication exposure assessment for tralomethrin. Therefore, the Agency anticipates 

conducting a comprehensive occupational risk assessment in registration review, which 

incorporates updated toxicological endpoints, exposure data, revised policies, and incident 

data as appropriate. 

• Tralomethrin belongs to the pyrethroid class of insecticides. This class also includes 

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

common mechanism of toxicity for naturally-occurring pyrethrins and synthetic pyrethroids 

(Proposed common mechanism grouping for the pyrethrins and pyrethroids, draft, May 19, 

2009 http://www.regulations.gov/search/Regs/home.html#documentDetail?R=09000064809a62df). 

This document was supported by the FIFRA Scientific Advisory Panel (SAP) and is 

available in the docket. See

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 SAP comments. Pesticides with a common mechanism of toxicity are

subject to cumulative risk assessment under the FQPA. Research is on-going by EPA’s 
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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 to pyrethroids. See 

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

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

health risk assessment for tralomethrin: 

o GDLN 870.7800 – Immunotoxicity Study 

o GDLN 870.6300 – Developmental Neurotoxicity (DNT)6

• Please refer to Tralomethrin. Human Health Assessment Scoping Document in Support of 

Registration Review (February 24, 2010), available in the docket, for a detailed discussion of 

the anticipated human health risk assessment and data needs for tralomethrin. 

Other Data Needs: 

• GLDN 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 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. 

 

6

 The registrant may choose to cite to the previously submitted DNT study for deltamethrin. 
10

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. 

Tralomethrin 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 our website: 

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

 

The Agency has created the following estimated timeline for the completion of the tralomethrin 

registration review. 

Registration Review for Tralomethrin– Projected 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 2015 – April - June 

Open Public Comment Period for Preliminary Risk Assessments 2016 – Oct. – Dec. 

Close Public Comment Period 2017 – Jan. - March 

Registration Review Decision 

Open Public Comment Period for Proposed Registration Review 

Decision 

 2017 – April - June 

Close Public Comment Period 2017 – July – Sept. 

Final Registration Review Decision and Begin Post-Decision Follow-up 2018 

Total (years) 8 

1. If the registrants choose to cite the previously submitted DNT study for deltamethrin, as explained above, rather 

than conducting a DNT study with tralomethrin, this time estimate will likely be shortened by approximately 

two years. 

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

estimate.

Guidance for Commenters:

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

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 tralomethrin 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.
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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 tralomethrin 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:

Tralomethrin 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=885. 

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 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 tralomethrin, based on information provided at 

http://iaspub.epa.gov/tmdl_waters10/attains_nation.tmdl_pollutant_detail?p_pollutant_group_id=88

5&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. 

Additional Information:

Stakeholders are also specifically asked to provide information and data that will assist the Agency 

in refining risk assessments, including any species-specific ecological effects determinations. The 

Agency is interested in receiving the following information: 

1. Confirmation on the following label information. 

a. sites of application 

b. formulations 

c. application methods and equipment 

d. maximum application rates 

e. frequency of application, application intervals, and maximum number of applications 

per season and per year 
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f. geographic limitations on use 

2. Use or potential use distribution (e.g. geographical distribution of relevant uses). 

3. Use history. 

4. Median and 90th percentile reported use rates (lb/A, lb 1K sq.ft) from usage data – national, 

state and county. 

5. Application timing (date of first application and application intervals) by use – national, 

state, and county. 

6. Usage/use information for non-agricultural uses. 

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

a. maximum reported use rate (lb/cc) from usage data – county 

b. median and 90th percentile number of applications – county 

c. total pounds per year – county 

d. the year the pesticide was last used in the county/sub-county area 

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

8. Typical application interval (days). 

9. State or local use restrictions. 

10. Ecological incidents specific to tralomethrin (non-target plant damage and avian, fish, 

reptilian, amphibian, mammalian mortalities, and bee or beneficial insect mortalities) not 

already reported to the Agency. 

11. Monitoring data. 

12. Any adverse effects in honey bees or other beneficial insects associated with the use of 

tralomethrin products. 

Next Steps:

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

received in a timely manner and then expects to issue a Final Work Plan in August of 2010 for 

tralomethrin. 
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II. FACT SHEET 

Background Information:

• Tralomethrin registration review case number: 7400 

• Tralomethrin PC Code: 121501; CAS # 66841-25-6 

• Tralomethrin was first registered in the United States in 1985. 

• Technical registrant: Bayer CropScience LP, Bayer Environmental Science, & Valent 

Biosciences Corporation 

• There are 44 FIFRA Section 3 active product registrations, including three manufacturing use 

registrations. 

• Pesticide Re-evaluation Division Contact: Joy Schnackenbeck (schnackenbeck.joy@epa.gov) 

• Registration Division Contact: Richard Gepkin (gebkin.richard@epa.gov). 

Use and Usage Information: (For additional details, please refer to Food/Feed & Non-Food/NonFeed Uses Considered in Registration Review Work Planning – Tralomethrin (121501) (December 

22, 2008) in the tralomethrin docket). 

• Tralomethrin is a pyrethroid insecticide registered for a variety of agricultural and residential 

uses including broccoli, cotton, lettuce, soybeans, sunflowers, household dwellings, 

ornamentals, lawns and turf, pet dwellings, garbage cans, paths, patios, wood protection, 

industrial outdoor areas, paved areas, agricultural farm premises, vehicles, ships, boats, 

caskets, warehouse premises, eating establishments, egg packing plants, food processing 

plants, food stores, greenhouses, hospital/medical institutions, meat processing plants. 

• Tralomethrin is used to control a variety of insects including aphids, worms, ants, gnats, 

moths, beetles, grasshoppers, mites, midges, spiders, ticks, yellow jackets, maggots, thrips, 

caterpillars, flies, fleas, and other pests in domestic, public health, agricultural, and industrial 

situations. 

• Tralomethrin is formulated as a solid bait, emulsifiable concentrate, granular formulation, 

liquid, pressurized gas, pressurized liquid, solid, and wettable powder. 

• Tralomethrin can be applied by aircraft, and a variety of ground sprayers, including hand 

pressure sprayer, low pressure sprayer, power sprayer, hand-held sprayer, and aerosol can.

• The four primary agricultural uses of tralomethrin are cotton, soybeans, lettuce and broccoli. 

A majority of this agricultural use is for lettuce and broccoli (approximately 61% and 37% 

respectively).

Recent Actions:

• There have been no recent actions.
15

Ecological Risk Assessment Status

The following summarizes ecological effects data from registrant-submitted studies and data 

available from open literature. The Agency has not previously conducted a comprehensive 

ecological risk assessment that integrates environmental exposure and ecological effects for all 

tralomethrin uses. Please refer to Registration Review – Preliminary Problem Formulation for 

Ecological Risk and Environmental Fate, Endangered Species, and Drinking water Assessments 

for Tralomethrin (March 23, 2010) located in the docket, for a detailed discussion of what is 

currently known about the environmental fate and ecological effects associated with 

tralomethrin. 

• Tralomethrin transforms to its structurally similar degradate deltamethrin in the environment. 

• Tralomethrin and deltamethrin are classified as very highly toxic on an acute basis to 

estuarine/marine and freshwater fish, aquatic-phase amphibians, and aquatic invertebrates. 

Tralomethrin and deltamethrin are also toxic on a chronic basis to freshwater fish and 

freshwater invertebrates. Tralomethrin is highly toxic to estuarine/marine invertebrates on a 

chronic basis. A chronic estuarine/marine invertebrate study is not available for 

deltamethrin. In addition, chronic estuarine/marine fish studies are not available for either 

tralomethrin or deltamethrin. 

• Tralomethrin and deltamethrin are practically nontoxic on an acute basis to birds, terrestrialphase amphibians and reptiles. Chronic tralomethrin exposure to birds can result in 

reproductive effects (reduced eggshell thickness and reduction of live three-week embryos). 

Similar reproductive effects from deltamethrin exposure have not been observed.

• Tralomethrin and deltamethrin are both highly toxic to terrestrial invertebrates, including 

beneficial insects such as honeybees.

• No data are available to evaluate toxicity of tralomethrin and deltamethrin to terrestrial and 

aquatic plants.

Human Health Risk Assessment Status

The following are key findings of the human health risk assessments conducted to support 

tralomethrin registered uses. Please refer to Tralomethrin. Human Health Assessment Scoping 

Document in Support of Registration Review (February 24, 2010) located in the docket for a detailed 

discussion of the human health risk assessment status. 
16

Hazard Characterization: 

In humans, tralomethrin is metabolized instantaneously to its structurally-similar degradate, 

deltamethrin. Therefore, tralomethrin endpoints for dietary, occupational and residential exposure 

scenarios are identical to those for deltamethrin and are based upon a combined 

tralomethrin/deltamethrin toxicity database. In addition, when EPA reassessed tralomethrin 

tolerances pursuant to FQPA, the Agency combined deltamethrin and tralomethrin exposure for risk 

assessment purposes. 

Tralomethrin has moderate acute toxicity through the oral and inhalation routes of exposure and low 

or mild acute toxicity through the dermal route of exposure. Tralomethrin is moderately irritating to 

the eye, non-irritating to the skin and is not a skin sensitizer. 

The carcinogenic potential of tralomethrin has not been classified. However, deltamethrin is 

classified as “not likely to be carcinogenic to humans” based on carcinogenicity studies in rats and 

mice. 

When EPA reassessed tralomethrin tolerances pursuant to FQPA in 2007 it concluded that an 

additional FQPA safety factor was not needed to protect the safety of infants and children from 

tralomethrin and deltamethrin exposure. At the time, there was no evidence of developmental, 

reproductive, or post-natal sensitivity. However, in 2009, EPA retained a 10X FQPA safety factor 

for deltamethrin for all exposure scenarios and durations for infants and children. This was based 

on an open literature study that showed children have a diminished capacity to detoxify deltamethrin 

relative to adults. (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. 

Dietary Risk: 

A screening level dietary risk assessment was performed for a proposed new use of deltamethrin on 

flax in 2009 and evaluated dietary exposure resulting from all registered uses of deltamethrin and 

tralomethrin. Drinking water exposure estimates were only calculated for deltamethrin use and did 
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not incorporate tralomethrin use. Dietary exposure risk estimates for children 12 years old and 

younger exceeded the Agency’s level of concern (infants 110% aPAD, children 1-2 130% aPAD, 

children 3-5 140% aPAD, children 6-12 110% aPAD). The new flax use was never granted. The 

Agency is currently working on a refined dietary exposure assessment evaluating registered uses of 

tralomethrin and deltamethrin, which incorporates updated usage and monitoring data. 

Residential and Recreational Risk: 

In the 1997 tolerance reassessment, the “flea infestation control” scenario was chosen to represent 

plausible but worst-case residential exposure from deltamethrin and tralomethrin use. Risks did not 

exceed levels of concern. 

Aggregate Risk: 

In the 1997 tolerance reassessment, aggregate exposure to tralomethrin and deltamethrin did not 

exceed levels of concern.

Occupational Risk: 

Occupational handler and post-application exposure assessments have not been previously 

conducted. 

Cumulative assessment: 

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

permethrin, cypermethrin, cyfluthrin, 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 (Proposed 

common mechanism grouping for the pyrethrins and pyrethroids, draft, May 19, 2009; 

http://www.regulations.gov/search/Regs/home.html#documentDetail?R=09000064809a62df ). This 

document was supported by the FIFRA Scientific Advisory Panel (SAP) and EPA will finalize the 

policy document on the pyrethroid common mechanism of toxicity taking into account the SAP 

comments. 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 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 to pyrethroids, http://www.epa.gov/pesticides/cumulative/ .
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Incidents

• In August 2009, a preliminary review of the Ecological Incident Information System (EIIS) 

and the Avian Monitoring Information System (AIMS) Database identified one incident for 

tralomethrin and one incident for deltamethrin. Tralomethrin was classified as a probable 

cause for an incident in 1994 involving phytotoxic effects to bushes near a residential 

application site. The incident associated with deltamethrin was 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 identified 

deltamethrin as the probable cause. 

• On June 30, 2009, an updated review of tralomethrin human incident reports was prepared by 

consulting the OPP Incident Data System (IDS). In the United States, from 2002 to the 

present, 90 incidents were reported for tralomethrin. Symptoms appear to be generic and it is 

uncertain whether they are related to exposure. Additionally, there is no clear pattern of 

toxicity or consistency of exposure scenarios across incidents. 

Tolerances and International Harmonization

• Tolerances are established under 40 CFR 180.422 for residues of tralomethrin that result 

from agricultural uses as well as use in food and feed handling establishments. Tolerances 

are established in terms of parent tralomethrin and its major metabolites, cis-deltamethrin and 

trans-deltamethrin. There are no Canada or Codex maximum residue limits (MRL) for 

tralomethrin. Mexico MRLs are harmonized with U.S. tolerances. 

Data Call-In Status

• There have been no issued data call-ins associated with tralomethrin.

Labels 

• Active Section 3 labels for tralomethrin can be obtained from the Pesticide Product Label 

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