Docket Number EPA-HQ-OPP-2010-0028 www.regulations.gov



## Oxamyl Summary Document Registration Review: Initial Docket September 2010

### TABLE OF CONTENTS

I. Preliminary Work Plan (PWP) 4

II. Fact Sheet 12

III. Summary of Data Gaps 20

________________________ ______________________ ____________________

Please Note

This Preliminary Work Plan and Fact Sheet su mmarize the Environmental Protection Agency's current position based on the following documents:

1. Registration Review: Preliminary Problem Formulation for Environmental Fate, Ecological Risk, Endangered Species, and Dr inking Water Exposur e Assessments for Oxamyl

. Dated July 28, 2010.

2. Oxamyl: Registration Review Scoping Document for Human Health Assessments . Dated August 18, 2010.

3. Appendix A: Label, Use, and Usage Table . Dated June 5, 2009.

4. Updated Review of Oxamyl Incident Reports . Dated November 24, 2009.

These and other supporting documents for the oxam yl registration review case may be found in the docket EPA-HQ-OPP-2010-0028 at http://www.regulations.gov.

Notices, documents, and public co mments associated with the N -Methyl Carbamate Cumulative

Risk Assessment are located in the docket EPA-HQ-OPP-2007-0935.

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### I. Preliminary Work Plan – Oxamyl

Introduction :

The Food Quality Protection Act (FQPA) of 1996 mandated a registration review program. All pesticides distributed or sold in the United Stat es (U.S.) generally must be registered by the Environmental Protection Agency (EPA or the Ag ency), based on scientific data showing that they will not cause unreasonable ri sks 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 unreasonabl e 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 prog ram, the Agency periodically r eevaluates pesticides to make sure that as change occurs, products in the mark etplace can be used safely. Information on this program is provided at: http://www.epa.gov/oppsrrd1/registration_review/.

The Agency is implementing the registration revi ew program pursuant to Section 3(g) of the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), a nd will review each registered pesticide every 15 years to determine whether it continues to meet th e 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 belie ves 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 de velop and commit to a final work plan and schedule for the registration review of oxamyl.

Oxamyl is a restricted use N -methyl carbamate insecticide, acaricide, miticide, nematicide, and plant growth regulator regi stered for use on a variety of fruits, vegetables, and field crops. There are currently no residential uses for oxamyl. It is a member of the N -methyl carbamate (NMC)

class of chemicals that share a common mechanism of toxicity and inhibit acetylcholinesterase.

The Interim Reregistration Eligibility Decision (IRED) for Oxamyl was completed in October 2000, and the Reregistration Eligibility Decision (RED) for Oxamyl was finalized in September 2007 upon completion of the Revised N-Methyl Carbamate Cumulative Risk Assessment.

In 2007 and 2008 EPA received several new a nd expanded use requests from DuPont, the technical registrant of oxamyl. Risk assessments were conduct ed in 2009 and 2010 to evaluate these amendment requests and to incorporate updated toxicological data into assessments for the currently labeled uses of oxamyl. The new risk assessments iden tified risks of concern for some existing uses of oxamyl. EPA is currently working with the registrant to mitigate these concerns. All of the new and expanded use amendment requ ests were withdrawn by DuPont in December

2009.

Anticipated Risk Assessment and Data Needs :

The Agency anticipates the need to require da ta and conduct an ecological risk assessment for oxamyl, including an endangered species assessme nt. For human health, revised dietary and

4occupational risk assessments may be needed dur ing registration review to incorporate updated toxicological endpoints, exposure estimates, and data may need to be required through a registration review data call-in. Below is a summary of the issues relevant to the registration review of oxamyl.

Ecological Risk:

• The most recent comprehensive ( i.e. , all use patterns) ecological risk assessment was completed in November 1999 and amended in March 2000 in support of the 2000 Oxamyl IRED.

• In 2007 and 2009, crop-specific eco logical risk assessments were conducted for oxamyl to evaluate FIFRA Section 3 proposed new uses on sugar beets and on dry bulb onions, shallots, and garlic, which were later withdrawn.

• The Agency completed an endangered species assessment evaluating the potential effects of oxamyl on one species consistent with a court order and settlement: Center for BiologicalDiversity v. Johnson, et al. , No. 02-1580 (N.D. Cal., October 20, 2006) [addressing the California red- legged frog (CRLF)]. On February 20, 2009, the Agency

transmitted the assessment to the U.S. Fish and Wildlife Service (USFWS) and initiated

formal consultation under Sect ion 7 of the Endangered Specie s Act. The Agency will consider any reasonable and prude nt measures or risk assessm ent considerations that may be included in the future responses to the Agency’s requests for consultation on the

CRLF.

Although the Agency has completed a speci es-specific determination for the CRLF relative to oxamyl use, a risk assessment that supports a complete endangered species

determination has not been conducted. The ecological risk assessment planned during registration review will allow the Agency to determine whether oxamyl’s use has “no effect” or “may affect” federally listed threat ened or endangered sp ecies (listed species) or their designated critical ha bitats. When an assessment c oncludes that a pesticide’s use “may affect” a listed species or its designate d critical habitat, the Agency will consult with the U.S. Fish and Wildlife Service and/or National Marine Fisheries Service (the Services), as appropriate.

• An updated ecological risk assessment of all registered uses of oxamyl will be conducted during registration review. The new assessment will incorporate the most up-to-date modeling methodologies, updated toxicological endpoints, and data submitted under the anticipated registration review data call-in.

• Data gaps exist in the environmental fate and toxicity databases for oxamyl. EPA anticipates requiring the following guideline studies in order to conduct a complete ecological risk assessment, including an endangered species assessment, for the registration review of oxamyl.

835.4400 – Anaerobic aquatic metabolism

5850.1025 – Acute toxicity es tuarine and marine or ganisms (oyster shell deposition) 850.1035 – Acute toxicity estuarine and marine organisms (mysid) 850.1350 – Aquatic invertebrate life cycle, saltwater (mysid) 850.1400 – Fish early life stage, freshwater 850.2100 – Avian oral toxicity (passerine species) 850.3040 – Field testing for pollinators 850.4100 – Terrestrial plant toxicity , seedling emergence, Tier II 850.4150 – Terrestrial plant toxic ity, vegetative vigor, Tier II 850.4400 – Aquatic plant growth, va scular plants, Tier II

• The Agency seeks additional information, particularly use and usage information, in order to conduct a refined, complete ecological risk assessment, including an endangered species assessment for oxamyl. See the “G uidance for Commenters” section below.

• Please refer to the July 28, 2010 document Registration Review: Preliminary Problem Formulation for Environmental Fate, Ecological Risk, Endangered Species, and Drinking Water Exposure Assessments for Oxamyl in the registration review docket (EPA-HQ-OPP-2010-0028) for a detailed discussion of the risk assessment and anticipated data needs.

Human Health Risk:

• A refined acute dietary (food a nd drinking water) risk assessment for all registered uses of oxamyl was conducted in July 2010 to inco rporate updated toxico logical data into assessments for the currently labeled uses of oxamyl. In addition, the Agency further refined the acute aggregate dietary assessment by incorpor ating the time and amounts consumed for each eating occasion from the Un ited States Department of Agriculture’s (USDA’s) Continuing Surveys of Food Intakes by Individuals food diaries to estimate exposures and risks on each eating occasi on throughout the day and factoring in the cholinesterase (ChE) inhibition hal f-life related to oxamyl exposure.

• The drinking water assessment may be updated as a result of mitigation implemented to address risks of concern identified in the most recent oxamyl dietary assessment. Additionally, the Agency may update the drinking water assessment during registration review if new environmental fate data are submitted, labeled use patterns are altered, residues of concern in drinking water are redefined, or the Agency’s drinking water assessment methodology is refined.

• The oxamyl dietary risk assessment may be updated as a result of mitigation implemented to address risks of concern identified in the July 2010 oxamyl aggregate (food and drinking water) acute dietary ri sk assessment. Additionally, an updated oxamyl acute dietary risk assessment may be required during registration review if there are changes to residues in food or drinking water, percent crop treated information, points of departure, or un certainty factors.

6• EPA does not anticipate conducting an oxa myl chronic dietary assessment during registration review. Acute exposure from oxa myl is the only duration of concern because of the rapid recovery of ChE activity.

• A revised occupational and residential e xposure (ORE) assessment for oxamyl was completed in July 2010 to incorporate updated toxicological data.

• The ORE risk assessment may be updated as a result of mitigation implemented to

address risks of concern identified in th e most recent assessment. Additionally, the Agency may update the assessments of oxamy l occupational handler and post-application activities during registration review if toxicological e ndpoints change, revisions to current policies and procedures for conducti ng these assessments are accepted, or new poisoning incident data are received.

• As there are no currently register ed uses of oxamyl at resident ial sites, residential handler and post-application assessments will not be conducted during registration review.

• The current label restriction against feeding cotton gin by-product to livestock should be deleted from oxamyl labels as recommended per the September 2000 human health assessment. To date, this label restriction has not been removed, but the labeling revision will be incorporated into future product label amendments.

• The toxicity database for oxamyl is nearly co mplete. However, EPA anticipates the need to require Guideline 870.7800, Immunotoxicity study, in orde r to conduct a complete

human health risk assessment for the registration review of oxamyl.

• Oxamyl shares a common mode of action with other NMCs and was included in the

Revised N -methyl Carbamate Cumulative Risk Assessment completed in 2007. Over time as new use requests, new data, or other information are submitted to the Agency for

individual chemicals within the cumulative group, single chemical risk assessments are updated. In the case of oxamyl, recent reque sts for new uses required updated risk

assessments that indicated risks of concern fo r a number of existing uses. The Agency is working to address risk concerns for the i ndividual chemical first. Subsequently, the Agency will incorporate any changes to the use patterns for oxamyl, as appropriate, into the cumulative assessment in order to reach a determination for the cumulative group as a

whole.

• Please refer to the August 18, 2010 document Oxamyl: Registration Review Scoping Document for Human Health Assessments in the registration review docket (EPA-HQOPP-2010-0028) for a detailed discussion of th e risk assessment and anticipated data

needs.

Endocrine Disruptor Screening Program :

As required under FFDCA section 408(p), EP A has developed the Endocrine Disruptor Screening Program (EDSP) to determine whether certain substances (inc luding pesticide active

7and other ingredients) may have an effect in humans or wildlife si milar 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 ap proach 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 estroge n, androgen, and or thyroid (E, A, or T) hormonal systems. Chemicals that go th rough Tier 1 screening and are found to have the potential to interact with E, A, or T hormonal systems will proceed to the next stag e of the EDSP where EPA will determine which, if any, of th e Tier 2 tests are necessary base d on the available data. Tier 2 testing is designed to identify a ny adverse endocrine related eff ects caused by the substance, and establish a quantitative relationship betw een 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 pesticid e active ingredients and 9 inert ingredients.

This list of chemicals was selected based on th e potential for human exposure through pathways such as food and water, residen tial activity, and certain post-applic ation agricultural scenarios.

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

Oxamyl is among the group of 58 pe sticide active ingredie nts on the initial list to be screened

under the EDSP. For information on the status of the orders issued under the EDSP for each chemical, please visit our website at http://www.epa.gov/endo/ a nd click on the “Status of EDSP Orders/DCIs” in the Highlights Box. Additiona l information on the EDSP, including the policies and procedures, the list of 67 chemicals, the test guidelines and the Tier 1 screening battery, can

also be found at this website.

8Timeline :

EPA has created the following estimated time line for the completion of oxamyl registration

review.

Registration Review for Oxamyl – Projected Regist ration Review Timeline

Activities Estimated Date Opening the Docket Open Docket and Public Co mment Period 2010 – September

Close Public Comment 2010 – November Case Development

Final Work Plan 2011 – February

Issue DCI 2011 – Oct – Dec

Data Submission 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

Decision 2015 – Oct – Dec.

Close Public Comment Period 2016 – Jan. – March Registration Review Decision and Begin Post-Decision Follow-up 2016 Total (years) 1 6

Guidance for Commenters :

The public is invited to comme nt on EPA’s preliminary regist ration review work plan and rationale. The Agency will carefully consid er all comments as well as any additional information or data provided in a timely manner pr ior to issuing a final wo rk plan for the oxamyl

case.

Trade Irritants:

Through the registration review process, the Ag ency intends to solicit information on trade irritants and, to the extent feas ible, take steps toward facilitating irritant resolution. Growers and other stakeholders are asked to comment on any tr ade 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:

Oxamyl is not identified as a cause of impairme nt for any water bodies listed as impaired under section 303(d) of the Clean Water Ac t, based on information provided at http://iaspub.epa.gov/tmdl_waters10/attains_ nation_cy.cause_detail_303d?p_cause_group_id=88 5. In addition, no Total Maximum Daily Loads (TMDL) have been developed for oxamyl, based on information provided at http://iaspub.epa.gov/ tmdl_waters10/attains_nation.tmdl_pollutant_

1 An assessment of the potential cumulative risk from the NMC class of insecticides ma y impact this time estimate.

9detail?p_pollutant_group_id=885&p_pollutant_gr oup_name=PESTICIDES. More information on impaired water bodies and TMDLs can be f ound 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 Im paired Water Body and Other Water Quality Data in OPP’s Registration Review Risk A ssessment 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 environmenta l justice, the fair tr eatment and meaningful involvement of all people, regardless of race, color, national origi n, or income, in the deve lopment, implementation, and enforcement of environmental laws, regulati ons, 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 thei r location, cultural practices, or other factors, may have atypical, unusually high exposure to oxamyl compared to the gene ral population. Please comment if you are aware of any sub-populatio ns that may have atypical, unusually high exposure compared to the general population.

Other Information:

Stakeholders are also specifically asked to prov ide information and data that will assist the Agency in refining the risk assessments, including any species-specific ecological determinations. The Agency is interested in obtaining the following information:

1. Additional information regarding the potential mode of action of this chemical as it relates to plants. The specific mode of acti on of oxamyl as it relates to growth regulation of plants ( i.e. the apple blossom thinning use) is unknown.

2. 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, applicati on intervals, and maximum number of applications per season

f. geographic limitations on use

3. use or potential use distribution ( e.g. , acreage and geographical di stribution of relevant crops)

4. use history

5. median and 90 th percentile reported use rates (lbs ai/1000 sq ft) from usage data – national, state, and county

6. application timing (date of first application and application interval s) by crop – national, state, and county

7. sub-county crop location data

8. usage/use information for non-agricultural uses

9. directly acquired county-level usage da ta (not derived from state level data)

a. maximum reported use rate (lbs a i/acre) from usage data – county

10b. percent crop treated – county

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

d. total pounds per year – county

e. the year the pesticide was last us ed in the county/sub-county area

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

10. typical application interval (days)

11. state or local use restrictions

12. ecological incidents (non-target plant damage and avian, fish, reptilian, amphibian and mammalian mortalities) not alr eady reported to the Agency

13. monitoring data

Next Steps :

After the 60-day public comment period closes , the Agency will review and respond to any comments received in a timely manner and then i ssue a Final Work Plan for the registration review of oxamyl.

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### II. FACT SHEET

Background Information :

• Oxamyl registration revi ew case number: 0253.

• Oxamyl PC code: 103801.

• Oxamyl CAS No.: 23135-22-0.

• Oxamyl was first registered for use in the United States in 1974.

• The Oxamyl IRED was completed in October 2000, and the RED was finalized in September 2007 upon completion of the Revised N -Methyl Carbamate Cumulative Risk

Assessment.

• The technical registrant for oxamyl is E. I. du Pont de Nemours and Company, Inc.

• There are currently two end- use products and one technical product registered for oxamyl. There are also 10 active state-sp ecific Special Local Need registrations.

• Product labels were amended in 2006 to in corporate labeling requirements from the Oxamyl RED.

• Tolerances for oxamyl are esta blished in 40 CFR Part 180.303.

• Pesticide Re-evaluation Di vision, Chemical Review Manager: Monica Wait, wait.monica@epa.gov

• Registration Division contact: Thomas Harris, harris.thomas@epa.gov

Use & Usage Information : (For additional details on label rates and use sites, refer to Appendix A: Label, Use, and Usage Table in the oxamyl docket EPA-HQ-OPP-2010-0028.)

• Oxamyl is a restricted use pesticide for retail sale to and use only by certified applicators or persons under direct superv ision of a certified applicator.

• Oxamyl is registered for use on 30 agricultu ral crops including terrestrial food, feed, and non-food crops. These uses are organized into 23 use groups on the labels.

• Both oxamyl end-use products are so luble liquid formulations. Vydate ® C-LV contains directions for use only on cotton, peanuts, potatoes, and tobacco. Vydate ® L contains directions for all registered uses.

• Oxamyl can be applied by aircraft, ground spray equipment (broadcast, in-furrow, and band treatment), chemigation (gravity, drip, lo w pressure, and sprinkle r), and a variety of soil incorporation and injection equipment.

• Depending on the specific use and application method, single maximum application rates of oxamyl range from 1 to 4 pounds of active ingredient per acre. Numerous geographic limitations are labeled by use gr oup or, in other cases, by spec ific directions within use

groups.

• EPA conducted a Screening Level Usage Analysis (SLUA) for oxamyl using data from the USDA’s National Agricultural Statistics Service (2001-2007), California Department of Pesticide Regulation Pesticide Use Repor ting database (2000-2005), private pesticide

12market research (2001-2007), and, in cases wh ere data were not available from other sources, the National Pesticid e Use Database of the CropLife Foundation (2002). The

SLUA indicated that there is an estimated 700,000 pounds of oxamyl used per year. The majority of oxamyl usage per year was on pot atoes (43% of total pounds oxamyl applied) and cotton (29%); other major uses include d mint (8.6%), dry bulb onions (5.8%), and celery (2.9%), followed by lesser uses on nineteen other reported crops.

Recent Actions :

• In May 2007, DuPont submitted a petition (PP6F7136) to EPA to establish a tolerance for the use of oxamyl on sugar beets, and in September 2007, they submitted a petition (PP7F7242) to establish a tolerance on wh eat. Also, in 2008 EPA received a proposed label amendment to expand several existing uses of oxamyl. Assessments of these proposed amendments are summarized in the “Ecological Risk Assessment Status” and

“Human Health Risk Assessment Status” se ctions of this Fact Sheet. The risk assessments are also posted in their entiret y in the Oxamyl Regi stration Review docket (EPA-HQ-OPP-2010-0028). All requests for new and expanded uses of oxamyl were withdrawn by DuPont in December 2009. EP A is currently working with DuPont to mitigate risk concerns identified with existing uses.

Ecological Risk Assessment Status :

Please refer to the Registration Review: Preliminary Problem Formulation for Environmental Fate, Ecological Risk, Endangered Species, and Drinking Water Exposure Assessments for Oxamyl , July 28, 2010 for a detailed discussion of the key findings of the most recent ecological risk assessments. A summary follows:

Summary of Risks:

• The most recent comprehensive ( i.e. , all use patterns) ecological risk assessment was completed in November 1999 and amended in March 2000 in support of the 2000 Oxamyl IRED. This assessment identified acute and chronic risks to terrestrial animals

and acute risk to freshwater invertebrates. Risks were also identified to federally-listed threatened / endangered species of terrestri al animals, amphibians, and freshwater and estuarine / marine invertebrates. However, mitigation measures specified in the Oxamyl RED, including voluntary cancellations/use term inations, reductions in rate and number of applications, soil in corporation, and a “restricted use” classification, were expected to reduce and adequately mitigate the potential ri sks. These mitigation measures have been incorporated into current oxamyl product labels.

• In 2007 and 2009, crop-specific eco logical risk assessments were conducted for oxamyl to evaluate several FIFRA Section 3 proposed new uses. The assessments identified potential risks of concern for adverse effect s from acute and chronic exposures to nonlisted and listed terrestrial animals ( i.e. , mammals, birds, reptiles, terrestrial-phase amphibians, and terrestrial invertebrates), potential risk of adverse effects from acute exposure for non-listed estuarine / marine i nvertebrates and for listed freshwater and

estuarine / marine invertebrates. Potential fo r risk of adverse effects was identified from

13chronic exposures to non-listed and listed estuarine / marine invertebrates. Lastly, the assessment identified potential for risk of a dverse effects to list ed nonvascular aquatic plants and listed terrestrial dicots. All of the requests for new and expanded uses were subsequently withdrawn by the oxamyl registrant.

• In 2009, the Agency completed an endangered species risk assessm ent of the potential effects of oxamyl on the threatened California red-legged frog ( Rana aurora draytonii ; CRLF) arising from current uses of oxamyl on us es that are registered in California. This endangered species risk assessment was part of the Center for Biological Diversity (CBD)

vs. EPA et al. (Case No. 02-1580-JSW (JL)) settlement entered in the Federal District

Court for the Northern District of Ca lifornia on October 20, 2006. The assessment

resulted in a determination that the use of pesticide products containing oxamyl is likely to adversely affect the CRLF. This determ ination is based on the potential for oxamyl to both directly and indirectly a ffect the species and result in modification to designated

critical habitat.

Human Health Risk Assessment Status :

Please refer to Oxamyl: Registration Review Scoping Document for Human Health Assessments

, August 18, 2010 for a detailed discussion of the ke y findings of the most recent human health risk assessment. A summary follows:

• Past oxamyl risk assessments rely in part on data from studies in which adult human subjects were intentionally exposed to a pesticide to determine their dermal and inhalation exposure. Many such studies, invo lving exposure to many different pesticides, comprise generic pesticide exposure database s such as the Pestic ide Handlers Exposure Database (PHED) and the Agricultural Reen try Task Force (ARTF) Database. EPA has reviewed all the studies supporting these multi- pesticide generic exposure databases, and has found no clear and convincing evidence that the conduct of any of them was either fundamentally unethical or significantly deficient relativ e to the ethical standards prevailing at the time the research was conducte d. All applicable re quirements of EPA’s

Rule for the Protection of Hu man Subjects of Research ( 40 CFR Part 26) have been satisfied, and there is no regulatory barri er to continued reli ance on these studies.

Hazard Characterization :

• Oxamyl is a member of the N -methyl carbamate class of chemicals sharing a common mode of action [inhibition of the acetyl chol inesterase enzyme (AChE)] with other NMC pesticides. NMCs bind loosely with AChE, thus allowing reactivation of the enzyme.

The acute inhibition of AChE in the brain and in red blood cells, therefore, is the exposure duration of concern for oxamyl.

• An updated benchmark dose (BMD) analysis, performed in November 2009 for the new Section 3 registration requests, utilized all of the appropr iate ChE data for the oxamyl hazard assessment. All of the requests for new and expanded uses were subsequently withdrawn by the oxamyl registrant.

14• A comparative cholinesterase assay (CCA ) was conducted for oxamyl to assess the relative sensitivity between adult and juvenile animals. The FQPA factor is based on a data-derived approach, as is consistent with other NMCs.

• Oxamyl is classified as “not likel y” to be carcinogenic to humans.

Dietary (Food and Drinking Water) :

• Refined drinking water exposure assessments were completed for oxamyl in 2009 and 2010 to evaluate FIFRA Section 3 proposed ne w uses on sugar beets and dry bulb onions, shallots, and garlic along with the existi ng uses of oxamyl. These drinking water assessments modeled all of the proposed and current oxamyl use groups. The assessments used maximum regional applica tion rates identified on product labels, regional percent cropped area factors, data submitted after the 2000 IRED, and current aquatic exposure models. Usage data that reflected upper-end rates and mean applications per year were also used to ch aracterize exposure resul ting from lower than maximum application rates for some use sites. All of the requests for new and expanded uses were subsequently withdr awn by the oxamyl registrant.

Refined surface water concentration estimates were up to 256 μg/L (acute), 9.1 μg/L (chronic), and 3.6 μg/L (cancer) for the maximu m use patterns (peppers and eggplant) in the most vulnerable growing region for each crop. Screening-level surface water modeling techniques were applied to ginger, pineapple, and yams because oxamyl is only applied to those crops grown in Hawaii or Pu erto Rico. EPA does not have appropriate refined modeling scenarios and data to re present Hawaii and Puerto Rico. Use on pineapple resulted in the highest screeni ng-level surface water e xposure estimate of 593 μg/L (acute).

Screening-level ground water exposure estima tes were up to 1.3 μg/L for the maximum use pattern (ginger root, only labeled for use in Hawaii), whereas, the maximum concentration detected in pr ospective ground water studies was 3.9 μg/L (detected below a site cropped to cotton at application).

• An updated dietary risk assessment was comp leted on existing oxamyl uses in July 2010 to incorporate revised water residue estimat es from the most recent drinking water risk assessment. This refined dietary assessment aggregated food and drinking water in one analysis, updated residue data, and incorporated percent crop treated data. As with other NMCs, an “eating occasion” analysis was conducted to account for cholinesterase inhibition and rapid reactivation of the en zyme (inhibition half-life of 150 minutes).

• The results of the acute dietary analysis fo r food alone was below EPA’s level of concern [less than 100% of the acute Populat ion Adjusted Dose (aPAD)] at the 99.9 th percentile of the exposure distribution for the general U.S. population and all population subgroups. The eating occasion analysis results for th e two population subgroups with the highest risk, children 1-2 years old and all infants, calculated food al one to be only 16% and 13% of the aPAD, respectively.

15When residues in drinking water resulting fr om various crops treated at maximum and/or reported application rates were added to the estimated residues in food, the exposures

exceeded 100% of the aPAD for most scenar ios. Exposures remained below 100% aPAD for carrot, celery, and eggplant at reported use rates and peanut, pear, sweet potato, and tobacco at maximum rates for both population subgroups, children 1-2 years old and all

infants.

• Due to the rapid recovery of ChE activity after exposure to oxamyl, a chronic dietary assessment was not conducted during the most recent risk assessment.

Residential (Non-occupational):

• As there are no currently registered uses at residential sites, residential handler and postapplication assessments were not include d in the most recent risk assessment.

Aggregate:

• An aggregate risk assessment typically ev aluates the combined risk from dietary exposure (food plus drinking water) and a ny residential uses. However, there are currently no residential uses for oxamyl; ther efore, the oxamyl aggregate risk assessment includes only dietary exposure. As noted above, a revised acute aggregate dietary exposure assessment, conducted to support Sect ion 3 registration requests, resulted in

risks concerns for several existing uses of oxamyl.

Occupational:

• The most recent occupational and residential exposure (ORE) assessment was completed in July 2010. The new ORE assessment included existing uses of oxamyl and incorporated new dermal and inhalation endpoints based on an updated BMD analysis.

• The 2010 ORE assessment indicated that both dermal and inhalation pathways were significant sources of exposure for occupational handlers. EPA has determined that there is potential for occupational ha ndlers to be exposed to oxamyl during mixing, loading, or application activities / scenarios. The short- and intermediate-term dermal risks did not exceed the Agency’s level of concern at some level of risk mitigation (personal protective equipment requirements, closed loading system s, etc.) for all handler scenarios, except:

 Mixing/loading liquid concentr ates to support aerial a pplications to cotton in

California and Arizona at 1.0 lb ai/A.

 Mixing/loading liquid concentr ates to support chemigati on applications at 2.0 lb ai/A;

 Applying sprays by aircraft to cotton in California and Arizona at 1.0 lb ai/A.

The short- and intermediate-term inhalation risks did not exceed the Agency’s level of concern at the baseline level (no respir ator) for all handler scenarios, except mixing/loading to support aerial applications to cotton in California and Arizona at the 1.0 lb ai/day application rate.

16The short- and intermediate-term combined dermal plus inhalati on risks did not exceed the Agency’s level of concern at some level of risk mitigation for all handler scenarios,
except:

 Mixing/loading liquid concentr ates to support aerial a pplications to cotton in

California and Arizona at 1.0 lb ai/A.

 Mixing/loading liquid concentr ates to support chemigati on applications at 2.0 lb ai/A;

 Applying sprays by aircraft to cotton in California and Arizona at 1.0 lb ai/A.

• The 2010 ORE assessment also determined that there is the potential for post-application exposures to individuals ente ring treated areas following oxamyl applications. As a result of the August 2000 ORE assessment, a re stricted-entry interv al (REI) of 48 hours was assessed for all crops except citrus, whic h has a 4-day REI. However, the 2010 ORE

assessment indicated that in order for risks to be below the Agency’s level of concern, REIs for many field crops would need to be longer than 2 days, depending on the crop and the post-application task (estimated REIs range from 12 hours to 13 days). The 2010

assessment also indicated that REIs for most tree crops would need to be longer than 2 days, depending on the crop and the post-applic ation task (estimated REIs range from 1 day to 27 days), in order to not exceed the Agency’s level of concern.

Based on these results, occupational post-ap plication exposure scenarios for many existing uses indicate risks of concern to the Agency and must be mitigated. See the

“Recent Actions” section for further information.

Cumulative:

• FQPA requires the Agency to consider the cumulative risks of chemicals sharing a common mechanism of toxicity. Oxamyl is a member of the N -methyl carbamate common mechanism group. The most recent cumulative risk assessment for the NMCs was issued on September 26, 2007.

• The NMC cumulative risk assessment conclude d that risks from food, drinking water, and residential exposure to N -methyl carbamate pesticides did not exceed the Agency’s level of concern, and that there was a reasonab le certainty that no harm would result from exposure to the NMC pesticides covered by the assessment.

Incidents :

• A search of the Environmental Incident Information System (EIIS) database for ecological incidents identified three incident s involving exposures to oxamyl. The first

incident involved the death of hundreds of fish and over 100 birds in Alamance County, North Carolina, in May of 1991. The certainty that the deaths of the animals were associated with exposure to oxamyl was cons idered “probable” but the legality of use

was indicated as “intentional misuse.” The second incident, with a certainty index of“possible” and legality of use indicated as “undetermined,” involved the death of a redcockaded woodpecker in Sussex County, Virg inia, in February of 2003. The third

17incident involved the deaths of 13 laughing gul ls and 1 cattle egret in the British Virgin Islands in 2004. The cause of mortality was defined as “toxicosis caused by both methomyl and oxamyl.” The certainty that the deaths of the birds we re associated with exposure to either pesticide was considered “possible,” and the legality of use was

“undetermined.”

• One source of uncertainty associated with the EIIS database is the nature of reporting of incidents. Many more incidents may have o ccurred due to oxamyl exposures but may not have been reported due to various factors. Therefore, the lack of an incident report does not necessarily indicate a lack of an incident.

• A summary report listing huma n incidents for oxamyl has been provided in the docket

item entitled Updated Review of Oxamyl Incident Reports

, November 24, 2009. The Office of Pesticide Programs Incident Data System (IDS) was consulted for reports of oxamyl poisoning incidents occurring in the Un ited States from 2002 to the present. The IDS includes reports of incidents from re gistrant reporting, fro m other government agencies, and from individual consumers. Of the five incidents reported, symptoms appear generic and not confirmed to be related to exposure, a nd there is no clear evidence of a trend or exposure pattern. Therefore, at this time, the Agency can not discern any suggestion of a trend or pattern regarding the health effects due to the alleged exposure to the pesticide oxamyl.

• The NIOSH SESNOR database was queried for acute occupational pesticide-related illnesses and identified five cases where exposure to oxamyl was determined to be definite, probable, or possible. The health effects most often reported include dermal (20%), cardiovascular (20%), respiratory (40 %), ocular (40%), gastrointestinal (60%), and neurological (60%). Symptoms are not mutually ex clusive, and a patient may have multiple symptoms. All cases were ranked lo w severity, and there were no fatalities.

Tolerances and International Harmonization :

• The residue of concern in plant commodities for risk assessment purposes based on cholinesterase inhibition is oxamyl al one. The tolerance expression for plant commodities is based on oxamyl and its metabolite oxime, because the analytical method

used for the field trials th at established the toleran ce converts oxamyl to oxime by employing a hydrolysis step. The toleranc es established in 40 CFR § 180.303 for residues of the insecticide oxamyl include it s metabolites and degradates in or on the commodities listed. Compliance with the tolerance levels is to be determined by measuring only the sum of oxamyl (methyl N,N -dimethyl- N -[(methylcarbamoyl)-oxy]- 1-thiooxamimidate) and its oxime meta bolite (methyl N,N-dimethyl-N-hydroxy-1- thiooxamimidate), calculated as the stoichiome tric equivalent of oxamyl, in or on the commodity. No tolerances have been establis hed or are currently required in the United States for any animal commodities. Adequate analytical methods exist for data collection

and tolerance enforcement.

• The Codex Alimentarius Commission and Me xico have established maximum residue limits (MRLs) for oxamyl, but they are not ha rmonized with all U.S. tolerances. Canada

18has not currently established any MRLs for oxamyl. Any oxamyl tolerances reassessed during registration review will be considered for possible harmonization with

international MRLs.

• A crop field trial study for co tton gin byproducts was recently reviewed by the Agency. The Agency’s review of the study indicated that a tolerance of 120 ppm should be established for residues of oxamyl on cotton gin byproducts.

Data Call-In Status :

• A generic data call-in (GDCI-103801-17865) was i ssued in November 2000 as a result of the data requirements listed in the 2000 Oxam yl IRED. All of the data requirements have

been fulfilled from this data call-in with the exception of Guideline 830.7050: UV/Visible Absorption. The Agency has re ceived a study intended to fulfill this guideline, which is currently in review.

Labels :

• A list of registration numbers for the oxamyl case is provided below, and the labels can

be obtained from the Pesticide Produ ct Label System (PPLS) website: http://oaspub.epa.gov/pestlabl/ppls.home.

Registration

# Registration Name Company Name % Active Ingredient

352-372 Vydate L Insecticide / Nematicide E.I. DuPont de Nemours and Co., Inc. 24

352-400 DuPont Oxamyl Technical 42 Insecticide /

Nematicide E.I. DuPont de Nemours and Co., Inc. 42

352-532 Vydate C-LV Insecticide / Nematicide E.I. DuPont de Nemours and Co., Inc. 42

CA060028 DuPont Vydate C-LV Insecticide / Nematicide E.I. DuPont de Nemours and Co., Inc. 42

CO010005 DuPont Vydate L Insecticide / Nematicide E.I. DuPont de Nemours and Co., Inc. 24

MD080003 DuPont Vydate C-LV Insecticide / Nematicide E.I. DuPont de Nemours and Co., Inc. 42

NV070002 DuPont Vydate L Insecticide / Nematicide E.I. DuPont de Nemours and Co., Inc. 24

NY080001 DuPont Vydate C-LV Insecticide / Nematicide E.I. DuPont de Nemours and Co., Inc. 42

NY990002 DuPont Vydate L Insecticide / Nematicide E.I. DuPont de Nemours and Co., Inc. 24

PA070002 DuPont Vydate C-LV Insecticide / Nematicide E.I. DuPont de Nemours and Co., Inc. 42

UT990004 DuPont Vydate L Insecticide / Nematicide E.I. DuPont de Nemours and Co., Inc. 24

WA000018 DuPont Vydate L Insecticide / Nematicide E.I. DuPont de Nemours and Co., Inc. 24

WI070005 DuPont Vydate L Insecticide / Nematicide E.I. DuPont de Nemours and Co., Inc. 24

1920 III. Summary of Data Gaps – Oxamyl

The table below summarizes all anticipated data needs for oxamyl in Section I, of this document (Preliminary Work Plan), the Registration Review: Prelim inary Problem Formulation for Environmental Fate, Ecological Risk, E ndangered Species, and Dr inking Water Exposure Assessments for Oxamyl , dated July 28, 2010, and the Oxamyl: Registration Review Scoping Document for Human Health Assessments , dated August 18, 2010.

Guideline

Number Anticipated Data Need Test

Material Estimated

Timeframe

835.4400 Anaerobic aquatic metabolism TGAI 24

850.1025 Acute toxicity estuarine and marine organisms 1 TGAI 12

850.1035 Acute toxicity estuarine and marine organisms 2 TGAI 12

850.1350 Aquatic invertebrate life cycle, saltwater TGAI 12

850.1400 Fish early life stage, freshwater TGAI 12

850.2100 Avian oral toxicity 3 TGAI 12

850.3040 Field testing for pollinators TGAI 24

850.4100 Tier II terrestrial plant toxicity, seedling emergence 4 TGAI 12

850.4150 Tier II terrestrial plant toxicity, vegetative vigor 4 TGAI 12

850.4400 Aquatic plant growth, vascular plants, Tier II 4 5 TGAI 12

870.7800 Immunotoxicity Study TGAI 12

1 Acute toxicity data should be submitted where mysid are exposed to TGAI oxamyl.

2 Acute toxicity data should be submitted where oysters are exposed to TGAI oxamyl.

3 A passerine study protocol must be submitted for revi ew by the Agency prior to initiation of this study.

4 Registrants 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.

5 A supplemental study is available to charac terize the effects of oxamyl on vascular aquatic plants (specifically duckweed) (MRID 45546103). This toxicity study was cons idered scientifically sound, but was cla ssified “supplemental” due to a lack of constant exposure of test organisms to the test material. Therefore, there is uncerta inty associated with the results of this study in that the endpoint obtained from this st udy may underestimate th e effects of oxamyl on aquatic vascular plants.