Docket Number: EPA-HQ-OPP-2010-0278 

http://www.regulations.gov 

 

Methiocarb Summary Document 

Registration Review: Initial Docket 

June 2010 

 

TABLE OF CONTENTS 

 Page # 

I. Preliminary Work Plan (PWP) 4 

II. Fact Sheet 10 

 

______________________________________________ 

Please Note 

This Preliminary Work Plan and Fact Sheet summarize the Environmental Protection 

Agency’s current position based on the following documents: 

1. Registration Review Preliminary Problem Formulation for Environmental Fate, 

 Ecological Risk, Endangered Species, and Drinking Water Exposure Assessments for 

 Methiocarb (April 6, 2010). 

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

 Review (March 17, 2010). 

3. Methiocarb: Review of Human Incidents (February 25, 2010). 

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

 Review of Methiocarb. Current as of June 2, 2009 (Report run date July 16, 2009). 

Additional supporting documents for methiocarb may be found in the docket EPA-HQOPP-2010-0278 which may be found on the Internet at www.regulations.gov. 

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I. Preliminary Work Plan 

Introduction:

The Food Quality Protection Act of 1996 mandated a pesticide registration review 

program. All pesticides distributed or sold in the United States generally must be 

registered by EPA, based on scientific data showing that they will not cause unreasonable 

risks to human health or the environment when used as directed on product labeling. The 

registration review program is intended to make sure that, as the ability to assess risk 

evolves and as policies and practices change, all registered pesticides continue to meet 

the statutory standard of no unreasonable adverse effects to human health or the 

environment. Changes in science, public policy, and pesticide use practices will occur 

over time. Through the registration review program, the Agency periodically reevaluates 

pesticides to make sure that as change occurs, products in the marketplace can be used 

safely. Information on this program is provided at 

http://www.epa.gov/oppsrrd1/registration_review/. 

The Agency is implementing the registration review program pursuant to Section 3(g) of 

the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), and will review each 

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

standard for registration. The Agency will consider benefits information and data as 

required by FIFRA. The public phase of registration review begins when the initial 

docket is opened for each case. The docket is the Agency’s opportunity to state what it 

knows about the pesticide and what additional risk analyses and data or other information 

it believes are needed to make a registration review decision. After reviewing and 

responding to comments and data received in the docket during this initial comment 

period, the Agency will develop and commit to a final work plan and schedule for the 

registration review of methiocarb. 

Methiocarb is an N-methyl carbamate insecticide, acaricide, molluscicide and avian 

repellent registered for use to control snails, slugs, mites and insects on ornamentals, 

lawns, and non-bearing deciduous and nut trees. There are no food or feed uses for 

methiocarb. The wettable powder formulations of methiocarb are restricted use 

pesticides available only to professional applicators and are applied by broadcast, foliar 

spray, and soil incorporation to ornamental plants and non-bearing deciduous and nut 

trees. One formulation of methiocarb is a general use pesticide sold as solid bait 

products, which can be used by homeowners and which are sprinkled over ornamental 

plant and non-bearing tree foliage, or applied to soil around plants grown in greenhouses, 

nurseries, or residential gardens. Potential metabolites of concern are methiocarb 

sulfoxide (MSO), methiocarb phenol (MP), and methiocarb sulfoxide phenol (MSOP).

Methiocarb is a member of the N-methyl carbamate (NMC) class of chemicals that share 

a common mechanism of toxicity and inhibit acetylcholinesterase by carbamylation of 

the serine hydroxyl group located in the active site of the enzyme. The “Revised NMethyl Carbamate Cumulative Risk Assessment” was completed in September 2007 

(available in the docket EPA-HQ-OPP-2007-0935). 

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Anticipated Risk Assessment and Data Needs:

The Agency anticipates conducting comprehensive human health and ecological risk 

assessments, including an endangered species assessment, for all uses of methiocarb and 

its metabolites of concern. Below is a summary of the issues relevant to the registration 

review process for methiocarb. 

Ecological Risk: 

• The most recent comprehensive ecological risk assessment for registered uses of 

methiocarb was conducted in 1994 in support of the Methiocarb RED. Acute 

levels of concern (LOC) were exceeded for birds, reptiles, mammals, and 

invertebrates, and chronic risk LOC were exceeded for birds, fish, and aquaticphase amphibians. 

• The degradation of methiocarb in soils is not well-defined, and more data are 

anticipated to be needed on aerobic soil metabolism. 

• Data are needed for aerobic and anaerobic aquatic metabolism because use on 

‘field grown ornamentals’ is not precluded by current methiocarb labels, and 

therefore must be assumed. 

• A fish accumulation data requirement (Guideline 165-4) was previously waived 

because methiocarb and its degradates were assumed to kill fish before toxic 

residues could bioaccumulate. Based on new guideline requirements, this study is 

anticipated to be required as part of the registration review process. 

• Toxicity data for methioicarb degradates (methiocarb sulfoxide (MSO), 

methiocarb phenol (MP), methiocarb sulfoxide phenol (MSOP), methiocarb 

sulfone (MSO2), and methiocarb sulfone phenol (MSO2P) are lacking. The 

residues of concern for exposure and risk assessment will be reconsidered prior to 

analysis. In the absence of confirmatory data indicating low toxicity concerns for 

the major degradates of methiocarb, they will be assumed of equal toxicity as the 

parent. 

• The Agency has not conducted a risk assessment that supports a complete 

endangered species determination for methiocarb. The ecological risk assessment 

planned during registration review will allow the Agency to determine whether 

methiocarb’s use has “no effect” or “may affect” federally listed threatened or 

endangered species (listed species) or their designated critical habitat. When an 

assessment concludes that a pesticide’s use “may affect” a listed species or its 

designated critical habitat, the Agency will consult with the U.S. Fish and 

Wildlife Service and/or National Marine Fisheries Service (the Services), as 

appropriate.

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

environmental fate and ecological risk assessment for parent methiocarb and its 

degradates, including a complete endangered species assessment. 

Environmental Effects Studies: 

o Guideline 850.1730 - Fish Bioconcentration Study

o Guideline 850.2300 - Avian Reproduction Test (Bobwhite Quail)

o Guideline 850.3030 - Honeybee Toxicity of Residues on Foliage

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o Guideline 850.1075, 850.1025 and 850.1035, 850.1045, or 850.1055 - 

Estuarine/Marine Fish & Invertebrate Acute Toxicity Tests

o Guideline 850.1300 & 850.1350 - Freshwater & Estuarine/Marine 

Invertebrate Life Cycle Toxicity Test

o Guideline 850.1400 - Freshwater & Estuarine/Marine Fish Early Life 

Stage Toxicity Test

o Guideline 850.4100 & 850.4150 - Terrestrial Plant Toxicity Tests (Tier I)

o Guideline 850.4400 - Aquatic Vascular Plant Growth (Tier I)

o Guideline 850.5400 - Aquatic Non-vasular Plant Growth (Tier I)

Environmental Fate Studies: 

These studies are anticipated to be needed to provide information on how, or by 

what mechanism, the pesticide degrades, the rate at which it degrades, where it 

goes, and what transformation products are formed once the compound is applied 

in the environment. 

o Guideline 835.4100 - Aerobic soil metabolism study

o Guideline 835.4300 - Aerobic aquatic metabolism study

o Guideline 835.4400 - Anaerobic aquatic metabolism study

o Guideline 835.1230 & 1240 - Leaching and adsorption/desorption

 (for methiocarb, methiocarb phenol, methiocarb sulfoxide, methiocarb 

 sulfoxide phenol).

o Guideline 835.6100 (Footnote 7) - Environmental chemistry analytical 

method in soil and independent laboratory validation

o Guideline 835.6200 (Footnote 7) - Environmental chemistry analytical 

method in water and independent laboratory validation

• Please refer to the Registration Review Preliminary Problem Formulation for the 

Environmental Fate, Ecological Risk, Endangered Species, and Drinking Water 

Exposure Assessments for Methiocarb in the methiocarb registration review 

docket (EPA-HQ-OPP-2010-0278).

 Human Health Risk: 

• The most recent dietary and drinking water risk assessments for methiocarb were 

conducted for the February 1994 Reregistration Eligibility Decision (RED) for 

methiocarb. 

• The toxicology database for methiocarb is not considered complete for the 

purposes of registration review because of data gaps for a comparative ChE study 

in adults and offspring and an immunotoxicity study. 

• A 2-generation reproduction study has been submitted and will be reviewed 

during registration review. 

• Both acute and subchronic neurotoxicity studies were previously identified as data 

gaps in the RED. However, information about N-methyl carbamate neurotoxicity 

is now known from the EPA National Health and Environmental Effects Research 

Laboratory (NHEERL) studies and from the carbamate cumulative assessment. 

Consequently, the Agency anticipates requiring an acute comparative 

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cholinesterase study for methiocarb, but does not anticipate requiring acute and 

subchronic neurotoxicity studies, or a developmental neurotoxicity study.

• A drinking water exposure assessment for groundwater and surface water has not 

been conducted and will be included during registration review. 

• Since there are no food or feed uses for methiocarb, dietary exposure from food is 

not expected. However, a decision on residues of concern in drinking water has 

not yet been made, and an updated drinking water assessment, as well as 

aggregate risk assessment (due to potential residential exposure), may be 

conducted to support the registration review of methiocarb.

• Both residential handler and residential postapplication exposure are possible and 

neither has been quantitatively assessed. Residential handler exposure could occur 

from application of bait formulation to lawns and (non-food) gardens. Residential 

postapplication exposure could occur from: 1) contact with commercially grown 

nursery plants previously treated with methiocarb; 2) dermal and incidental oral 

exposure to children from contact with treated garden plants; and 3) dermal and 

incidental oral exposure to children through contact with or ingestion of pellets or 

granules of the bait treatment. Both residential handler and postapplication 

exposures will be assessed during registration review. 

• The Agency anticipates conducting a revised occupational handler exposure 

assessment and a postapplication assessment for methiocarb for all handler 

exposures, except the egg treatment use pattern, to reflect updates in Agency 

occupational/residential exposure assessment methodologies.

• The Agency anticipates requiring the following studies in order to conduct a 

complete human health assessment: 

o Special Study - Comparative Cholinesterase Assay 

o Guideline 870.7800 - Immunotoxicity 

• Prior to a final registration review decision for methiocarb, the Agency will 

determine if there is any new information, such as new hazard or exposure data or 

information on changes to the use pattern, which could affect the 2007 Revised 

NMC Cumulative Risk Assessment. If so, the Agency will revisit the cumulative 

risk assessment. 

• Please refer to the Methiocarb. Human Health Assessment Scoping Document in 

Support of Registration Review in the methiocarb registration review docket 

(EPA-OPPTS-OPP-2010-0278) for a detailed discussion of previous human 

health assessments. 

Other Anticipated Data Needs: 

• OPPTS GLN 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.

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Endocrine Disruptor Screening Program (EDSP): 

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

Screening Program (EDSP) to determine whether certain substances (including pesticide 

active and other ingredients) may have an effect in humans or wildlife similar to an effect 

produced by a “naturally occurring estrogen, or other such endocrine effects as the 

Administrator may designate.” The EDSP employs a two-tiered approach to making the 

statutorily required determinations. Tier 1 consists of a battery of 11 screening assays to 

identify the potential of a chemical substance to interact with the estrogen, androgen, or 

thyroid (E, A, or T) hormonal systems. Chemicals that go through Tier 1 screening and 

are found to have the potential to interact with E, A, or T hormonal systems will proceed 

to the next stage of the EDSP where EPA will determine which, if any, of the Tier 2 tests 

are necessary based on the available data. Tier 2 testing is designed to identify any 

adverse endocrine related effects caused by the substance, and establish a quantitative 

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

Between October 2009 and February 2010, EPA issued test orders/data call-ins for the 

first group of 67 chemicals, which contains 58 pesticide active ingredients and 9 inert 

ingredients. This list of chemicals was selected based on the potential for human 

exposure through pathways such as food and water, residential activity, and certain postapplication agricultural scenarios. This list should not be construed as a list of known or 

likely endocrine disruptors. 

Methiocarb was one of several pesticides removed from the initial list of pesticides to be 

screened because changes in their use and application methods eliminated the potential 

for exposure in one or more pathways. Specifically, the remaining agricultural uses for 

methiocarb are granular applications in nurseries and greenhouses, and current 

registrations no longer include use on food crops. Although methiocarb is only present in 

two exposure pathways (water and residential), under FFDCA sec. 408(p) the Agency 

must screen all pesticide chemicals. Accordingly, EPA anticipates issuing future EDSP 

orders/data call-ins for all Registration Review cases, including those for which EPA has 

already opened a Registration Review docket for a pesticide active ingredient. 

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

67 chemicals, the test guidelines and the Tier 1 screening battery, please visit our 

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

Timeline: 

EPA has created the following estimated timeline for the completion of the methiocarb 

registration review. 

Registration Review for Methiocarb – Projected Registration Review Timeline

Activities Estimated Date 

Opening the docket 

Open Docket and Public Comment Period 2010 – June 

Close Public Comment 2010 – August 

Case Development 

8
 

Final Work Plan 2010 – November 

Issue DCI 2011 – Jul.-Sept. 

Data Submission 2013 – Jul.-Sept. 

Open Public Comment Period for Preliminary Risk Assessments 2015 – Jan.-Mar. 

Close Public Comment Period 2015 – Apr.-Jun. 

Registration Review Decision 

Open Public Comment Period for Proposed Registration Review 

Decision 

 2015 – Jul.-Sept. 

Close Public Comment Period 2015 – Oct.-Dec. 

Final Registration Review Decision and Begin Post-Decision 

Follow-up 

 2016 

Total (years) 6 

Guidance for Commenters:

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

and rationale. The Agency will carefully consider all comments as well as any additional 

information or data provided in a timely manner prior to issuing a final work plan for 

methiocarb. 

Trade Irritants: 

Through the registration review process, the Agency intends to solicit information on 

trade irritants and, to the extent feasible, take steps toward facilitating irritant resolution. 

Growers and other stakeholders are asked to comment on any trade irritant issues 

resulting from lack of Maximum Residue Limits (MRLs) or disparities between U.S. 

tolerances and MRLs in key export markets, providing as much specificity as possible 

regarding the nature of the concern. 

Since there are no food or feed uses for methiocarb, there should be no issues regarding 

trade irritants. 

Water Quality: 

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

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

http://iaspub.epa.gov/tmdl_waters10/attains_nation_cy.cause_detail_303d?p_cause_grou

p_id=885. In addition, no Total Maximum Daily Loads (TMDL) have been developed 

for methiocarb, based on information provided at 

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

oup_id=885&p_pollutant_group_name=PESTICIDES. More information on impaired 

water bodies and TMDLs can be found at http://www.epa.gov/owow/tmdl/. The Agency 

invites submission of water quality data for this pesticide. To the extent possible, data 

should conform to the quality standards in Appendix A of the OPP Standard Operating 

Procedure: Inclusion of Impaired Water Body and Other Water Quality Data in OPP’s 

Registration Review Risk Assessment and Management Process (see: 

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

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

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Environmental Justice: 

EPA seeks to achieve environmental justice, the fair treatment and meaningful 

involvement of all people, regardless of race, color, national origin, or income, in the 

development, implementation, and enforcement of environmental laws, regulations and 

policies. To help address potential environmental justice issues, the Agency seeks 

information on any groups or segments of the population who, as a result of their 

location, cultural practices, or other factors, may have atypical, unusually high exposure 

to methiocarb, compared to the general population. Please comment if you are aware of 

any sub-populations that may have atypical, unusually high exposure compared to the 

general population.

Additional Information: 

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

the Agency in refining the risk assessments, including any species-specific ecological 

effects determinations. 

The Agency is interested in receiving the following information: 

1. Confirmation on the following label information 

a. sites of application 

b. formulations 

c. application methods and equipment 

d. maximum application rates 

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

 applications per season 

f. geographic limitations on use 

2. Use or potential use distribution (e.g., acreage and geographical distribution of 

relevant crops) 

3. Use history 

4. Median and 90th percentile reported use rates (lbs ai/acre) from usage data – 

national, state, and county 

5. Application timing (date of first application and application intervals) by crop – 

national, state, and county 

6. Sub-county crop location data 

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

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

 b. percent crop treated – county 

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

 d. total pounds per year – county 

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

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

8. Typical application interval (days) 

9. State or local use restrictions 

10. Ecological incidents (non-target plant damage and avian, fish, reptilian, 

amphibian and mammalian mortalities) not already reported to the Agency 

11. Surface and/or ground water and air monitoring data 

10
 

Next Steps: 

After the 60-day public comment period closes, the Agency will review any comments 

received in a timely manner and then issue a Final Work Plan for this pesticide. 

11
 

II. FACT SHEET 

Background Information:

• Methiocarb [4-methylthio-3,5-xylylmethylcarbamate] registration review case 

number: 0577 

• Methiocarb PC Code: 100501; CAS #: 2032-65-7 

• Technical registrant: Gowan. 

• Currently, there are 1 technical and 1 manufacturing use pesticide (MUP) 

products and 5 end-use products. End use products are restricted use pesticides 

(RUPs) except for one granular homeowner product. 

• First registered in 1972. 

• Reregistration Eligibility Decision (RED) published February 1994. 

• Pesticide Re-evaluation Division Chemical Review Manager (CRM): Jude 

Andreasen: andreasen.jude@epa.gov

• Registration Division Product Contacts: Venus Eagle: eagle.venus@epa.gov

Use & Usage Information:

For additional details on label rates and allowed uses, please refer to Appendix A in the 

methiocarb registration review docket (EPA-OPPTS-OPP-2010-0278). 

• Methiocarb is an N-methyl carbamate insecticide, acaricide, molluscicide and 

avian repellent registered for use to control snails, slugs, mites and insects on 

ornamentals, lawns, and non-bearing deciduous and nut trees. There are no food 

or feed uses. 

• Methiocarb is sold as wettable powder formulations as restricted use products 

available only to professional applicators and applied by broadcast, foliar spray, 

and soil incorporation to ornamental plants and non-bearing deciduous and nut 

trees. Methiocarb is also sold as granular bait products, one of which is a general 

use product for homeowners. Granular products are sprinkled over ornamental 

plant and non-bearing tree foliage, or applied to soil around plants grown in 

greenhouses, nurseries, or residential gardens. 

• Methiocarb is registered as a bird repellent for use by the U.S. Department of 

Agriculture. Common eggs are injected with methiocarb to condition egg 

predator bird species, such as crows, not to prey upon Federally listed threatened 

or endangered species, or eggs of other species designated to be in need of special 

protection. 

• National usage figures are not available for methiocarb. Usage in California 

during the period from 2005 to 2007 was 2,460, 1,788, and 1,766 pounds of the 

active ingredient respectively. 

Recent Actions:

• Methiocarb was included in the cumulative risk assessment completed for the Nmethyl carbamate group of pesticides in September 2007. 

• A previously acceptable absorption/desorption study was reclassified as 

unacceptable, and several other absorption/desorption or leaching studies were 

12
 

determined to be not scientifically valid. These data are currently noted as data 

gaps (see “Anticipated Risk Assessment and Data Needs” above).

Ecological Risk Assessment Status:

The following are key findings of the most recent methiocarb ecological risk assessment, 

conducted in support of the 1994 RED. Please refer to the Registration Review: 

Preliminary Problem Formulation for Environmental Fate, Ecological Risk, Endangered 

Species, and Drinking Water Exposure Assessments for Methiocarb for a detailed 

discussion of the ecological risk assessment. 

• A national level risk assessment for methiocarb was completed in support of the 

1994 Methiocarb RED. 

• The primary environmental concerns identified in the previous risk assessment 

were acute risks to birds, mammals, and honeybees. Data on risk to terrestrial 

plants are not available and are anticipated to be required.

• Acute LOCs were exceeded for aquatic invertebrates, and chronic LOCs were 

exceeded for fish (as well as aquatic-phase amphibians for which fish serve as 

surrogates) for all outdoor use sites and formulations. There are no toxicity data 

available for estuarine/marine fish, estuarine/marine invertebrates, or aquatic 

plants. Chronic data on methiocarb are only available for freshwater fish. LC50 

values for the most sensitive fish and invertebrate species tested are less than 1 

mg/L. Data on risk to vascular and non-vascular plants are not currently 

available for methiocarb and are anticipated to be required. 

Human Health Risk Assessment Status:

The following are key findings of the most recent methiocarb human health risk 

assessment, conducted in support of the 1994 RED. Please refer to the Human Health 

Assessment Scoping Document in Support of Registration Review for methiocarb for a 

detailed discussion of the human health risk assessment. 

Hazard Characterization: 

• As with other N-methyl carbamates, the principal toxic effects induced by 

methiocarb are related to its cholinesterase-inhibiting activity. 

• However, the 1994 RED reported that the dermal endpoint (embryonic 

resorptions and incomplete ossification) was selected from the rabbit dermal 

developmental toxicity study. However, there was no assessment of 

cholinesterase inhibition, which is considered the most sensitive endpoint for the 

N-methyl carbamates. 

• Methiocarb studies were negative for mutagenicity. No increase in tumors was 

reported in the rat chronic/carcinogenicity study, and a mouse carcinogenicity 

study is not anticipated as being needed because there are no food uses for 

methiocarb. 

Dietary (Food and Water):

• Since methiocarb is a non-food/non-feed use pesticide, exposure to methiocarb 

from consuming treated foods is not expected. 

13
 

• A determination of the potential residues of concern in drinking water was not 

incorporated into previous risk assessments of methiocarb, but the Agency 

anticipates conducting an assessment for registration review that will include 

available surface water and groundwater monitoring data. 

 

Residential: 

• Residential handler exposure from granular application to lawns and gardens, and 

post application exposure from purchased nursery plants previously treated with 

methiocarb were not previously assessed, but the Agency anticipates conducting 

an assessment for registration review. 

 

Occupational: 

• The RED specified risk mitigation measures for occupational handlers, including 

additional personal protective equipment (PPE) of coveralls and gloves to 

mitigate handler dermal risks. The RED also specified respirators for all handlers 

during ventilation activities, and dust masks for mixer/loaders using wettable 

powders. 

• There is potential worker exposure from postapplication exposure associated with 

non-bearing nut and deciduous trees and ornamental plants. Postapplication 

exposure was not assessed but a quantitative assessment will be conducted during 

registration review, which may include data from the already submitted (MRID # 

44522702) dislodgeable foliar residue study. 

• No occupational exposure assessment is required for the egg treatment use, and 

postapplication exposure is not expected from this use. 

Reliance on Human Studies: 

• Past methiocarb 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, involving exposure to many 

different pesticides, comprise generic pesticide exposure databases such as the 

Outdoor Residential Exposure Task Force (ORETF) Database and the Pesticide 

Handlers Exposure Database (PHED). 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 relative to the ethical standards 

prevailing at the time the research was conducted. All applicable requirements of 

EPA’s Rule for the Protection of Human Subjects of Research (40 CFR Part 26) 

have been satisfied, and there is no regulatory barrier to continued reliance on 

these studies. 

• EPA is aware of a previously submitted study involving intentional exposure of 

human subjects to methiocarb (MRID 44724302). In the course of registration 

review EPA will consider this study, as well as any other research involving 

intentional exposure of human subjects to methiocarb brought to its attention. If 

EPA decides to rely on any of these studies, EPA will ensure that all applicable 

regulatory requirements are met, including but not limited to the requirements for 

14
 

EPA ethics review and Human Studies Review Board review of certain research 

involving intentional exposure of human subjects. 

 

Aggregate: 

• As there are no food uses for methiocarb, the only potential for dietary exposure 

is through drinking water. The Agency will need to determine the residues of 

concern and evaluate the potential aggregate risks from water and residential uses 

to support the registration review of methiocarb. 

Cumulative Risk Characterization (CRA): 

• Methiocarb was assessed as part of the N-methyl carbamate cumulative risk 

assessment (CRA), completed in September 2007. No cumulative risks of 

concern for methiocarb were identified in that assessment, and no additional 

mitigation was specified. 

Incident Reports:

Ecological Incidents: 

• Preliminary reviews of the Ecological Incident Information System (EIIS) in 

December 2009 showed no reported wildlife or plant incidents involving 

methiocarb. However, the Agency received a report (not yet entered into the 

EIIS) from the National Wildlife Health Center for an incident involving the death 

of 30 bats (Myotis lucifugus) in July 2009 in Valley County, ID, which tested 

positive for carbofuran and methiocarb. The Avian Incident Monitoring System 

(AIMS) contained one incident involving both methiocarb and carbofuran in an 

intentional misuse resulting in the death of three bald eagles, six chickens, four 

red-tailed hawks, and one great horned owl. 

Human Incidents: 

• The Methiocarb Incident Report dated February 25, 2010 is based on two cases 

reported to the NIOSH/SENSOR from 1998 to 2006. No incidents were reported 

to the Incident Data System from 2002 to the present. Although the two incidents 

reported to NIOSH/SENSOR involved a leak/spill, they were in different settings 

(one of which resulted in a low severity outcome) and are not considered a pattern 

or trend. The Agency will continue to monitor the incident information and if a 

concern is triggered additional analyses will be included in the risk assessment. 

Tolerances:

• There are no food or feed uses for methiocarb, and there are consequently no U.S. 

tolerances. 

Data Call-In (DCI) Status:

• DCI’s were issued for methiocarb in 1994 and 1995 requiring a number of human 

health and environmental effects studies. Some studies have been submitted and 

15
 

reviewed, classified as either acceptable, supplemental, or invalid. Other studies 

are no longer required due to changes in the use pattern. A fish accumulation 

study was waived because methiocarb and its degradates in aquatic systems were 

assumed to kill fish before residues could accumulate to levels of concern in fish 

tissue. Based on new guideline requirements, this study (fish bioconcentration) is 

anticipated to be required as part of the Registration Review process. Invalid or 

supplemental studies are being required for Registration Review, or being held in 

reserve if nonguideline data are available for a variety of species.

Labels: 

There are 7 current Section 3 labels and no Special Local Need (SLN) labels. Labels can 

be obtained from the Pesticide Product Label System (PPLS) website: 

http://oaspub.epa.gov/pestlabl/ppls.home. 

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