1 Docket Number EPA

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- 0751 www.regulations.gov



## Methomyl Final Work Plan Registration Review

March 20113 METHOMYL FINAL WORK PLAN

Introduction

This is the Environmental Protection Agency’s (EPA’s) Final Work Plan for the registration review of methomyl . This work plan includes the expected registration review timeline. The work plan also addresses public comments received concerning the Preliminary

Work Plan in the Summary Document , which was posted in the metho myl registration review docket ( EPA

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- 0751 ), and any other comments concerning the initial docket postings. The Summary Document provided information on what EPA knows about the pesticide and what additional risk analyses and data or information the Agency believes are needed to make a registration review decision.

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. Changes in science, public policy, and pesticide use practices will occur over time. The registration review program is intended to make sure that, a s the ability to assess risk evolves and as policies and practices change, all registered pesticides continue to meet the statutory standard. The public phase of registration review begins when the initial docket is opened for each case. Information on t his program is provided at: http://www.epa.gov/oppsrrd1/registration_review/

.

Methomyl is an N

- methyl carbamate insecticide currently registered for use on a wide variety of sites includin g fiel d, vegetable, and orchard crops, and on turf (sod farms only)

. Methomyl is generally a restricted use pesticide [ based on percent active ingredient (a.i.)] and there are currently no homeowner uses. However, certain low percentage a.i. formulations are not designated as restricted use and can be used around livestock quarters, commercial premises

and refuse containers

. M ethomyl was first registered in t he United States in 1968

. A Reregistration Eligibility Decision (RED) was completed in 199 8. Methomyl is the primary metabolite of thiodicarb, which is also an insecticide. The thiodicarb registration review docket (EPA

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- 0432) opened on December 16, 2009.

Methomyl and thiodicarb a re member s of the N

- methyl carbamat e (NMC) class of chemicals that share a common mechanism of toxicity and inhibit acetylcholinesterase (AChE) by carbamylation of the serine hydroxyl group located in the active site of the enzyme. The

“Revised N

- Methyl Carbamate Cumulative Risk Assessment ” was completed in September 2007

and is a vailable in the docket at EPA

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- 0935

.4 Comments Received on Preliminary Work Plan :

Multiple comments were received during the 60

- day public comment period on the planned ecological assessment and human health scoping document discussed in the Preliminary Work

Plan

. However, these comments do not alter the Agency’s work plan outlined in the Preliminary Work Plan. The representative comments and Agency’s responses are summarized

in this document. In the Preliminary Work Plan , EPA also solicited comments on three specific topics: environmental justice, water body impairment, and trade irritants. No comments or

information were rec eived during the comment period . For further discussion on these

comment s please see the Summary of Comments and Agency Response Section.

Anticipated Risk Assessment and Data Needs

The Agency intends to require data needed to conduct a comprehensive ecological risk

assessment

, including an end angered species risk assessment

, and a revise d human health risk

assessment for all uses of methomyl

. Below is a summary of the issues relevant to the registration review of methomyl and the data the Agency anticipates requiring

.

Ecological Risk:

**•** The most recent comprehensive risk assessment for methomyl was conducted in 1998 in support of the Reregistration Eligibility Decision (RED) document

.

**•** The Agency has conducted several assessments on some endangered species, but has not
conducted an ecological risk assessment that supports a complete endangered species

determination for methomyl

. The ecological risk assessment planned during registration

review will allow the Agency to determine whether methomyl ’s use has “no effect” or “may affect” federally listed threatened or endangere d 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, th e Agency will consult with the

U.S. Fish and Wildlife Service ( FWS ) a nd/or National Marine Fisheries Service (NMFS) (the Services), as appropriate.

**•** On January 19, 2011, the Center for Biological Diversity and the Pesticide Action

Network North America filed a lawsuit in the United States District Court for the

Northern Dis trict of California, against the Environmental Protection Agency (EPA) for allegedly failing to undergo consultation with the United States Fish and Wildlife Service and the National Marine Fisheries Service regarding the effects of over 350 pesticides,

in cluding methomyl , on over 200 endangered and threatened species throughout the United States (Center for Biological Diversity, et al. v. EPA, et al., No. C 11

- 00293 (N.D.Cal.).5 **•** The Agency anticipates needing the following data in order to conduct a comple te ecological risk assessment , including a complete endangered species assessment

, for methomyl :

**•** GDLN 835.2240

– Aqueous photolysis

**•** GDLN 835.4100

– Ae robic soil m e tabolism

**•** GDLN 835.4300

– Aerobic a quatic m etabolism

**•** GDLN 835.4400

– Anaerobic a quatic m eta bolism

**•** GDLN 850.2100

– Avian o ral t oxicity (passerine species )

**•** GDLN 850.2300

– Avian r eproduct ion s tudy (mallard duck)

**•** GDLN 850.4100

– Terrestrial p lant toxicity: Tier I I Seedling Emergence

**•** GDLN 850.4150

– Terr estrial p lant toxicity: Tier I I Vegetative V i gor

**•** GDLN 850.4400

– Aquatic p lant g rowth: v ascular p lants

**•** GDLN 850.5400

– Aquatic p lant g rowth: nonvascular plants

Please refer to the “ Registration Review: Preliminary Problem Formulation for Environmental Fate, Ecological Risk, Endangered Species, and Drinking Water Exposure Assessments for Methomyl, ” dated July 16, 2010 , for a more detailed discussion of the anticipated ecological risk

assessment and data needs.

Human Health Risk:

**•** The most recent comprehensive human health risk assessment for methomy l was completed in support of the 1998 RED

. A dietary assessment was completed for

m ethomyl as part of the NMC Cumulative Risk Assessment.

**•** Since the last human health exposure and risk assessment in support of the 1998 RED the crop use sites and applic ation scenarios have remained the same with the exception of the cancellation of methomyl use on strawberries and grape s
, and the restriction on handheld

devices

.

**•** A revised dietary risk assessment

, may be need ed to include updated percent crop treated

es timates, updated monitoring data, changes in toxicological endpoints, and revised estimated drinking water concentrations

.

**•** The methomyl tolerance expression in 40 CFR 180.253 will be reviewed during registration review to ensure that it appropriately cove rs the metabolites and degradates of methomyl 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.6 **•** A residential handler exposure as sessment may be needed during registration review

. Even though there are currently no homeowner uses for methomyl , there is a potential for exposure to baits in public areas. In addition, a residential post

- application assessment may be needed to support the use of methomyl on sod farms

.

**•** R evised occupational handler and postapplication assessment may be need ed based on the most current toxicity profile and Agency policies.

**•** Due to the rapid onset and recovery of A ChE effects from methomyl

, a n acute aggr egate risk assessment is the only appropriate aggregate assessment that may be needed to support registration review. This acute assessment would incorporate any new point of departures or uncertainty factors identified for methomyl

.

**•** The Agency anticipat es requiring the following data in order to conduct a complete human health risk assessment for methomyl :

o GDLN 870.7800

– Immunotoxicity Study

o Non

- guideline

– Acute Inhalation Study This acute inhalation study would provide AChE data showing the time t o peak AChE inhibition as well as the dose

response of AChE inhibition at the peak inhibition. A study protocol should be provided to the Agency for review before the onset of such study

.

**•** Prior to a final registration review decision for methomyl , the Ag ency will determine if there is any new information, such as new hazard or exposure data or information on changes to the use pattern, that would affect the cumulative risk assessment. Should the Agency determine that new information on methomyl is availa ble that could potentially impact the cumulative risk assessment and result in a risk of concern, the Agency will

revisit the cumulative risk assessment.

**•** Please refer to the “ Methomyl: Registration Review Scoping Document for Human Health

Assessments ,” d ated July 1 3

, 2010 , available in the docket, for a detailed discussion of the anticipated human health risk assessment and data needs for methomyl

.7 Endocrine Disruptor Screening Program

As required by FIFRA and FFDCA, EPA reviews numerous studies to as sess potential adverse outcomes from exposure to chemicals. Collectively, these studies include acute, subchronic and chronic toxicity, including assessments of carcinogenicity, neurotoxicity, developmental, reproductive, and general or systemic toxicity. These studies include endpoints which may be susceptible to endocrine influence, including effects on endocrine target organ histopathology, organ weights, estrus cyclicity, sexual maturation, fertility, pregnancy rates, reproductive loss,

and sex ratios in offspring. For ecological hazard assessments, EPA evaluates acute tests and chronic studies that assess growth, developmental and reproductive effects in different taxonomic groups. As part of its reregistration decision , EPA reviewed these data and selected the most sensitive endpoints for relevant risk assessment scenarios from the existing hazard database. However, as required by FFDCA section 408(p), methomyl is subject to the endocrine screening part of the Endocrine Disruptor Screening Program (EDSP).

EPA has developed the EDSP to determine whether certain substances (including pesticide active and other ingredients) may have an effect in humans or wildlife similar to an effect produced by a “naturally occurring estrogen, or other such endocri ne 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 wit h 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 deter mine which, if any, of the Tier 2 tests are necessary based on the available data. Tier 2 testing is designed to identify any adverse endocrine

- related effects caused by the substance, and

establish a dose

- response relationship between the dose and the E, A, or T effect.

Under FFDCA section 408(p), the Agency must screen all pesticide chemicals. Between October 2009 and February 2010, EPA issued test orders/data call

- ins for the first group of 67 chemicals, which contains 58 pesticide active ingred ients a nd 9 inert ingredients. M ethomyl was included on that list and has been issued an order to conduct the Tier 1 testing. Once all required Tier 1 and Tier 2 data have been received and reviewed, the endpoints and safety factors used for risk

assessment pur poses will be examined and a new risk assessment performed if necessary. For further information on the status of the EDSP, the policies and procedures, the list of 67 chemicals, future lists, the test guidelines and the Tier 1 screening battery, please v isit our

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

.8 Timeline

The Agency has created the following estimated timeline for the completion of the methomyl registration review.

Registration Review for Methomyl

– Projected Registration Review Timeline

Activities Estimated Date Opening the D ocket Open Docket and Public Comment Period 2010

– September

Close Public Comment 2010

– November Case Development

Final Work Plan 2011

– March

Issue DCI 2011

– Oct

– Dec

Data Sub mission 2013

– Oct

– Dec Open Public Comment Period for Draft Risk Assessments 2015

– April

– June

Close Public Comment Period 2015

– July

– Sept Registration Review Decision Open Public Comment Period for Proposed Registration Review

D ecision 2015

– Oct

– Dec

Close Public C omment P eriod 201 6

– Jan

- March Registration Review D ecision and Begin P ost

- D ecision F ollow

- up 2016 Total ( years ) 1 6

1. An assessment of the potential cumulative risk from the NMC cl ass of insecticides may impact this time estimate

.9 Summary of Comments and Agency Responses:

The methomyl registration review docket was open for a 60

- day comment period beginning on September 22 , 2010. Multiple comments were received from the public and the registrants, however, these com ments do not alter the Agency’s work plan outlined in the Preliminary Work

Plan . Below are the Agency’s responses to representative comme nts concerning data requirement . For more detailed/complete responses, please see Agency memos “ Methomyl: Response t o Public Comments on Registration Review Preliminary Work P lan ,” dated

01/25 /2011, Agency memo “ Response to Public Comments on the Registration Review Problem Formulation for Ecological Risk, Environmental Fate, Endangered Species, and Drinking Water

Asses sments for Methomyl ,” dated 12/17/2010

, and Agency memo “ BEAD Response to the California Grape and Tree Fruit League (CGTFL ) Regarding the Agency’s Action to Discontinue Methomyl Use on Table Grapes ”, all are available in the docket.

Comments from the Phy sicians Committee for Responsible Medicine (PCRM)

PCRM Comment 1: “The Summary Document indicates that the Agency may request testing for avian acute oral toxicity. We strongly support the use of the newly revised OECD Test Guideline 223 for the

acute av ian oral toxicity test...”

EPA Response: To date the OECD has adopted the TG 223 guideline and has issued a valid ation report. At this

time EPA is actively evaluating the results of the OECD validation report to determine if the TG 223 effects endpoints a nd dose/response information adequately address the purposes of the avian acute oral data requirement as described in 40 CFR Part 158. Until the Agency’s

evaluation of that vali dation report is completed, EPA will not classify avian toxicity studies perfo rmed using the TG 223 protocol and the studies cannot be used to fulfill current data requirements.

PCRM Comment 2: “In response to past comments on the avian acute oral toxicity test... ‘EPA is not likely to accept studies conducted under the OECD guide line unless additional study validation is conducted for passerine species (from EFED Response to Comments on Preliminary Work Plan for Sodium Acifluorfen )’... If the Agency is interested in collecting all data in consideration of the use of the

223 then it should not state that it will not accept information gathered according to this protocol.”

EPA Response:

EPA will consider all data submitted regarding the potential toxicity of pesticides. In reading through the previous Agency response, we understand how the sentence ‘EPA is not likely to accept studies conducted under the OECD guideline...” could be misunderstood. To clarify10 what was meant, the Agency will not be able to classify studies conducted using TG223 and passerines as ‘acceptable’ (and, thus, fulfilling guideline requirements) until it is verified that the OECD TG 223 using passerines adequately addresses the purposes of the passerine acute oral data requirement as described in 40 CFR Part 158.

Comments from the American Bird Conservancy (ABC)

ABC Comment 1: ABC requests that EPA require an avian oral toxicity test using a passerine species and an avian reproduction study with the mallard duck.

EPA Response: EPA will be requiring both of these studies as noted in the methomyl Summary Docume nt and

the Problem Formulation.

ABC Comment 2: ABC requests an avian reproductive and developmental study using a passerine species. ABC recognizes that EPA does not have an official Standard Operation Procedure (SOP) to recommend to registrants for pass erine reproductive studies, however, we urge EPA to look beyond the lack of SOP and investigate the potential toxicity of this compound.

EPA Response: No data are available to EPA that show methomyl is more toxic to passerine species than it is to

bobwhi te quail ( Colinus virginianus ) or mallard ducks ( Anas platyrhynchos ) on a chronic exposure basis as it relates to reproductive endpoints. Therefore, at this time, it is believed that the data from the reproductive studies in the bobwhite quail and mallard duck studies will be adequate for assessing potential risks of methomyl to birds from chronic exposure.

ABC Comment 3: EPA should evaluate the risk from puddles of standing water within 24 hours of irrigation. If the puddle model indicates a risk to b irds, this method of application should be withdrawn, or specific monitoring requirements should be implemented.

EPA Response: EPA is actively working on tools that will address assessing risks to non

- target animals (including birds) from exposure through drinking water, including puddles. If these tools are available, this potential exposure pathway will be considered quantitatively in the methomyl ecological risk assessment conducted for Registration Review.

ABC Comment 4 : Methomyl is known to be tox ic to birds and in one incident was used to de liberately poison 18 pigeons. ABC request EPA to consider requiring all methomyl end

- use products to be labeled as restricted use, to prevent further abuse. Because the registration review process is so prolo nged,11 ABC requests that the EPA consider interim label changes such as, lower application rates, application right before dark, and requiring the plowing in (incorporation) of the methomyl 5G Granule formulation immediately after application.

EPA Response : Once the required ecological data are generated and new ecological risk assessments have been completed, EPA will recommend that appropriate mitigation be added to labels if the risk

assessments indicate risks of concern

.

Comment s from the California G rape and Tree Fruit Leagu e (CGTFL)

CGTFL Comment 1 : 2006 Alternatives Assessment did not adequately identify appropriate pests and control for CA table g rapes. 2006 AA references had very little input from the California table grape industry.

EPA Re sponse: The May 17, 2006 Alternatives Assessment for Methomyl on Grapes was for all grapes (raisin, table, and wine) nationwide, and therefore, did not focus on any one type of grape or state. Information was obtained from the publicly available crop pro files and pest management strategic plans available on the Integrated Pest Management Centers website ( http://www.ipmcenters.org ). The Crop Profile for Grapes (Table) in California was produced by University resear chers, IPM advisors, growers, and a member of the California Table Grape Commission under the name "California Grape Advisory Team."

A subsequent analysis was conducted in 2008 that focused on California table grapes which did include industry input. I n the 2008 EPA review, the additional pests of concern and their control practices specific to California table grapes were considered. In addition, pest information specific to California table grapes was submitted in support of an emergency exemption re quest
in 2008.

Comments from DuPont Crop Protection (D CP )

DCP Comment 1 : For the following studies DuPont believes existing data meets these data needs.

GDLN 835.2240

– Aqueous Photolysis

GDLN 835.4100

– Aerobic Soil Metabolism

GDLN 835.4300

– Aerob ic Aquatic Metabolism

GDLN 835.4400

– Anaerobic Aquatic Metabolism

EPA Response:

The problem formulation for methomyl, which may be found in the docket at www.regulations.gov ( EPA

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- 0751 ), provides detail s on the environmental fate12 data deficiencies and information needed to conduct an exposure assessment for Registration Review. We look forward to receiving data that address these needs.

DCP Comment 2 : GDLN 850.2300

– Avian reproduction study (mallard d uck)

. DuPont has conducted an avian reproduction study with the mallard (MRID 41898601) that satisfies this data requirement. This study was categorized as core and determined to fulfill the guideline requirement in the methomyl RED document.

E PA Respons e: "The study cited (MRID 41898601) cannot be used to fulfill guideline requirements because there were effects noted at all treatment concentrations, a NOAEC was not determined. In addition, the NOAEC from the mallard reproduction study is <50 mg a.i./kg

- diet based on decreases in adult male body weight, which indicates that the mallard duck may be more sensitive to methomyl than the bobwhite quail on a chronic exposure basis. Therefore, the Agency recommends a reproduction study (GDLN 850.2300) with the mallard duck is needed to fulfill this data gap."

DCP Comment 3 : On July 15, 2010, DuPont submitted comments on the NMFS Biological Opinion and EPA’s proposed measures. A response from the Agency is pending.

E PA Response: The Agency has reviewed the co mments DuPont submitted relative to the Endangered Species Protection Bulletins resulting from ESA consultation with the National Marine Fisheries Service. A letter is currently being prepared to explain how the Agency handl ed all of the comments it

received on those bulletins.

DCP Comment 4 : Regarding Table 3.2 in the Problem Formulation, “(t)he Lannate® SP formulation should have Chemigation listed under Methods of Application.”

E PA Response:

EPA appreciates the information provided by DuPont. E PA will r eview the Lannate® LV label

a nd will make changes to the method of application as appropriate when conducting the ecological risk assessment for methomyl during the Registration Review process.

Next Steps:

The Agency plans to issue a DCI for methomyl in 2011 for the data gaps listed under Summary of Data Gaps below. The information received in response to this DCI will be used to conduct the planned human health, ecological risk, and endangered species assessment for methomyl

.13 Summary of Data Gaps

– M ethomyl

The table below summarizes all outstanding data needs for methomyl

Guideline

Number Data Requirement Test

Material Estimated

Timeframe

(Months)

835.224 0 Aqueous photolysis TGAI 24

835.4100 Aerobic Soil Metabolism* TGAI 24

835.4300 Aerobic Aqu atic Metabolism TGAI 24

835.4400 Anaerobic Aquatic Metabolism TGAI 24

850.2100 Avian Oral Toxicity (passerine species) TGAI 12

850.2300 Avian Reproduction Study (Mallard duck) TGAI 12

850.4100 Terrestrial Plant toxicity: Tier I Seedling Emergence ** TG AI 12

850.4150 Terrestrial Plant toxicity: Tier I Vegetative Vigor ** TGAI 12

850.4400 Aquatic Plant Growth: Tier II Vascular Plants ** TGAI 12

850.5400 Aquatic Plant Growth: Tier II Algae ** TGAI 12

Non

- GDLN Acute Inhalation Study TGAI 12

870.7800 Immu notoxicity Study TGAI 12

* Foreign Soil Taxonomic Classification. Soil taxonomic classifications for foreign soils studied in MRID 45473401 are necessary in order to compare the studied soils to domestic soils representative of methomyl use sites.

**Reg istrants may opt to conduct a Tier I study, with the understanding that any adverse effects (even if <25%) will necessitate a Tier II study. A Tier II study will enable the Agency to conduct an endangered species assessment for nontarget plants.