Methomyl
Methomyl is an n-methyl carbamate insecticide used to control foliage and soil-borne insect pests on a variety of food and feed crops, including field vegetables and orchard crops. The only non-agriculture use of methomyl is a fly bait product.
There are no residential uses of methomyl. All methomyl products, except the bait formulations, are classified as Restricted Use Pesticides (RUPs). RUPs can only be used by or under the direct supervision of specially trained and certified applicators. Learn more about RUPs.
Using Methomyl Products Safely
Methomyl is categorized as highly to moderately toxic when a person is exposed to the pesticide via mouth, eyes or inhalation. Additionally, methomyl is a cholinesterase inhibitor in humans via the oral, dermal and inhalation routes of exposure. This means that, if a human is exposed to methomyl via mouth, skin or inhalation, methomyl can overstimulate the nervous system resulting in nausea, dizziness, confusion and at very high exposures (e.g., accidents or major spills), respiratory paralysis and death. To minimize health impacts, EPA classified methomyl products used in agricultural settings as RUPs.
Furthermore, all registered methomyl products can be safely used by following label directions. Safety precautions found on the product label include:
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wearing protective clothing and chemical resistant gloves at all times;
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distancing yourself from the chemical when mixing it;
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using personal protective equipment like a respirator during application; and
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observing restricted-entry intervals.
Actions Taken to Mitigate Methomyl's Risk
EPA has taken several actions over the years to reduce carbamate use, which includes methomyl, to further protect human health, especially the health of children who may be more sensitive to pesticides. From 1995 to 2013, exposures from food to carbamates fell by approximately 70 percent.
During the periodic evaluation of methomyl, EPA found drinking water risks from certain methomyl uses. In January 2015, manufacturers agreed to several actions to reduce these risks, including:
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voluntarily cancelling the use of methomyl on barley, oat and rye;
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limiting methomyl’s use on wheat to Idaho, Oregon and Washington;
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reducing the number of methomyl applications for corn, celery, and head and leaf lettuce; and
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reducing the number of methomyl applications and the seasonal maximum methomyl application rate for peppers.
Also in January 2015, EPA and manufacturers reached an agreement to stop making and selling some fly bait products and to add label language that clarifies the approved uses. This action was intended to reduce the illegal use of methomyl fly bait products to kill wildlife, an issue that has been reported to EPA by several states in the past.
Methomyl's Registration Review Process
Methomyl is currently undergoing registration review, a program that re-evaluates all pesticides on a 15-year cycle.
In 2019, EPA released methomyl’s draft risk assessments. EPA found human health risks of concern to bystanders at the field edge and ecological risks of concern to non-listed mammals, birds, reptiles, amphibians, fish and terrestrial and aquatic invertebrates.
In 2020, EPA released a Proposed Interim Decision (PID) for methomyl that proposed mitigation measures to ensure that use of methomyl products will not result in unreasonable adverse effects on the environment, consistent with EPA’s obligations under the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA).
In 2021, the Agency released the Biological Evaluation (BE) for methomyl. The BE contains EPA’s effects determinations and analysis of the potential exposure of methomyl to listed species and their designated critical habitats. Since EPA made a number of “likely to adversely affect” determinations, EPA initiated consultation with the U.S. Fish and Wildlife Service and the National Marine Fisheries Service (the Services) after the completion of the final BE in March 2021. During consultation, the Services may determine that additional measures are needed to avoid jeopardy to listed species and adverse modification of critical habitats from the use of methomyl. The Services may also identify measures to reduce the potential for take. Read EPA’s announcement about this action.
In 2022, EPA proposed revisions to the 2020 PID for methomyl. The revised methomyl PID is a pilot case for identifying and proposing early mitigation for three vulnerable endangered species through the registration review process while formal endangered species consultation with the Services is ongoing. This effort initiates one of four strategies EPA identified in its comprehensive 2022 Endangered Species Act (ESA) workplan that aims to improve protection for listed species and meet the Agency’s ESA obligations.
All documents related to the registration review can be located in docket number EPA-HQ-OPP-2010-0751 located at www.regulations.gov.
Additional Information
- Chemical Search
- Docket for methomyl: EPA-HQ-OPP-2010-0751