Introduction

This is the Environmental Protection Agency’s (EPA or the Agency) Final Work Plan 

(FWP) for the registration review of tralomethrin. This FWP includes the expected registration 

review timeline. This work plan also addresses public comments concerning the Preliminary 

Work Plan in the Summary Document, which was posted in the tralomethrin registration review 

docket (Docket Number EPA-HQ-2010-0116), and any other comments concerning the initial 

docket postings. The tralomethrin Summary Document provided information on what EPA 

knows about the pesticide and what additional risk analysis data or information the Agency 

believes are needed to make a registration review decision. 

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. Changes in 

science, public policy, and pesticide use practices occur over time. 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 that statutory standard. The public 

phase of registration review begins when the initial docket is opened for each case. Information 

on this program is provided at http://www.epa.gov/oppsrrd1/registration_review/. 

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). 

This document finalizes the work plan for the tralomethrin registration review process. 

Actions since Publication of PWP

In August 2010 the Agency received a voluntary cancellation request from the technical 

registrant, Bayer Crop Sciences, to cancel all registered tralomethrin product registrations. A 

Federal Register Notice (FRN) will be published announcing EPA’s receipt of Bayer’s request to 

voluntarily cancel all tralomethrin product registrations. This notice will initiate a 30-day 

comment period. EPA intends to grant this request at the close of the comment period for this 

announcement unless the Agency receives substantive comments within the comment period that 

would merit its further review of the requests, or unless the registrant withdraws their request 

within this period. This action will cancel the sole technical product registration for 

tralomethrin. Therefore, the Agency anticipates that no further risk assessments or additional 

data will be needed in support of this registration review if these pending product cancellations 

become final and effective. If the cancellations become final and effective the Agency will issue 

a proposed final decision for tralomethrin. However, if the pending cancelations are withdrawn 

or otherwise not implemented, the risk assessment and data needs outlined in this Final Work 

Plan will be required in support of this registration review. 

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Comments Received on Preliminary Work Plan

On March 31, 2010 EPA opened a 60-day public comment period for the registration 

review of tralomethrin. The comment period ended on June 1, 2010. The Preliminary Work 

Plan document can be located in the tralomethrin registration review docket (EPA-HQ-OPP2010-0117) at www.regulations.gov. 

 In the PWP, EPA solicited comments on three specific topics: environmental justice, 

water body impairment and trade irritants. No comments or information were received during 

the public comment period concerning these issues. EPA also received no comments during the 

60-day public comment period on the initial docket for tralomethrin. 

Risk Assessment and Data Needs

Should the pending registration terminations become final and effective, the human 

health and ecological risk assessments and data needs as described in this FWP will no longer be 

needed. However, if the pending terminations of all tralomethrin product registrations are 

withdrawn or otherwise not implemented, a comprehensive ecological risk assessment, including 

an endangered species risk assessment, is anticipated as being needed for all uses of tralomethrin. 

Dietary, residential, occupational, and aggregate human exposure risk assessments are also 

anticipated as being needed 

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 addressing combined exposures from deltamethrin applied as a pesticide 

and deltamethrin originating from applications of tralomethrin. However, should the pending 

registration terminations become final and effective, a combined exposure assessment from 

deltamethrin (applied as a pesticide) and deltamethrin originating from application of 

tralometherin is not anticipated as being needed because all tralomethrin uses will be cancelled. 

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 

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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 requiring the following data in order to conduct a complete 

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

Tralomethrin: 

o GDLN 835.1230 or 825.1240 – Leaching and adsorption/desorption1

o GDLN 835.2120 – Hydrolysis 

o GDLN 835.2240 – Photodegradation in Water 

o GDLN 835.2410 – Photodegradation on Soil 

o GDLN 835.4100 – Aerobic Soil Metabolism 

o GDLN 835.4300 – Aerobic Aquatic Metabolism 

o GDLN 835.4400 – Anaerobic Aquatic Metabolism 

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

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

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

o GDLN 850.1025 – Acute Toxicity Estuarine and Marine Organisms (oyster) 

(typical end-use product) 

o GDLN 850.1035 – Acute Toxicity Estuarine and Marine Organisms (mysid) 

(typical end-use product) 

o GDLN 850.1075 – Acute Toxicity Estuarine and Marine Organisms (fish) (typical 

end-use product) 

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

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

o GDLN 850.2100 –Avian Oral Toxicity (passerine species) 

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

& Tier 2)2

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

plant toxicity) (Tier I and Tier II)3

o GDLN 850.1790 – Whole Sediment: Chronic Invertebrates (estuarine/marine) 

(Leptocheirus plumulosus) 

o GDLN 850.1790 – Whole Sediment: Chronic Invertebrates (freshwater) (Hyalella 

azteca and Chironomus dilutus) 

 

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). 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. 

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 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. 

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Deltamethrin: 

o GDLN 835.4300 – Aerobic Aquatic Metabolism 

o GDLN 835.4400 – Anaerobic Aquatic Metabolism 

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

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

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

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

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

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

o GDLN 850.2100 –Avian Oral Toxicity (passerine species) 

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

& Tier 2)4

 

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

plant toxicity) (Tier I and Tier II)

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o GDLN 850.1790 – Whole Sediment: Chronic Invertebrates (freshwater) (Hyalella 

azteca and Chironomus dilutus) 

o GDLN 850.1790 – Whole Sediment: Chronic Invertebrates (estuarine/marine) 

(Leptocheirus plumulosus) 

• The following data would be used to inform removal percentages by waste water 

treatment, which is an input to the Exposure and Fate Assessment Screening Tool’s (EFAST) down-the-drain module. The Office of Pesticide Programs will continue to 

confer with the Office of Water with the goal of refining our down-the-drain assessment 

for registration review. These studies should be conducted on deltamethrin. 

o Publicly Owned Treatment Works (POTW) Effluent Monitoring 

o Publicly Owned Treatment Works (POTW) Treatability Study 

• For a more detailed discussion of the anticipated ecological risk assessment needs refer to 

the Registration Review – Preliminary Problem Formulation for Ecological Risk and 

Environmental Fate, Endangered Species, and Drinking water Assessments for 

Tralomethrin (March 23, 2010), which is located in the docket. 

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 

 

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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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. EPA has recently determined that, as an 

alternative to the generation and submission of a new DNT study, pyrethroid registrants 

may instead choose to cite the six previously submitted DNT studies for pyrethroid 

pesticides. 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. Additional 

information can be found on EPA’s website: 

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

• The Agency has not previously conducted residential handler or post-application 

exposure assessments for tralomethrin. Therefore, the Agency anticipates conducting 

residential handler and post-application exposure risk assessments during registration 

review for tralomethrin. These assessments will take into account, as appropriate, any 

changes in toxicological endpoints, new exposure data, revisions to the current policies 

and procedures for conducting exposure assessments, and any new poising incident data 

on tralomethrin. 

• 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 

post-application exposure assessment for tralomethrin. Therefore, the Agency anticipates 

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conducting a comprehensive occupational risk assessment in registration review for 

tralomethrin. These assessments will take into account, as appropriate, any changes in 

toxicological endpoints, new exposure data, revisions to the current policies and 

procedures for conducting exposure assessments, and any new poising incident data on 

tralomethrin. 

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

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

lambdacyhalothrin, among others. 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. 

• 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) 

• 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 

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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 drinking water, residential activity, and certain postapplication 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 EPA’s website: 

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

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 Docket 

Open Docket and Public Comment Period 2010 – March 

Close Public Comment 2010 – May 

Case Development 

Final Work Plan 2010 – September 

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 

*This time estimate will shorten should the pending registration terminations become final and effective. 

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Next Steps

If the pending termination of all tralomethrin product registrations is withdrawn or 

otherwise not implemented, the Agency anticipates requiring several ecological effects and 

human health studies through a Data Call-In (DCI) Notice, expected to be issued in 2011. This 

new information will be used to conduct the risk assessments outlined in this FWP for all 

tralomethrin uses. 

However, if the pending registration terminations become final and effective and a 

cancellation order is issued, the Agency anticipates that it will not be necessary to conduct new 

risk assessments for tralomethrin and, therefore would anticipate issuing a proposed final 

decision pursuant to 40 CFR Part 155.53(c)(2) and 40 CFR Part 155.58. 

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