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Methyl Parathion Risk Management Decision


Current as of: August 2, 1999
(amended August 10, 1999)

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EPA has accepted voluntary cancellation of many of the most significant food crop uses of methyl parathion, one of the most toxic and most widely used organophosphate pesticides. Methyl parathion has been found to pose unacceptable dietary risks to children. Removing these crop uses considerably reduces risks to children through food, as well as risks to workers and the environment.


Methyl parathion is one of the most toxic organophosphate pesticides. The organophosphate can over stimulate the nervous system causing nausea, dizziness, confusion, and at high exposures, respiratory paralysis and death. EPA's risk assessment showed that methyl parathion could not meet the FQPA safety standard as the pesticide is currently registered. The acute dietary risk to children age one to six exceeded the reference dose (or amount that can be consumed safely over a 70-year lifetime) by 880%. To mitigate the high dietary risk to children, EPA accepted voluntary cancellation of those crops that contribute most to the children's' diet. These canceled uses represent 90% of the dietary risk to children. Removing these crop uses brings the estimated dietary risk down to 78% of the reference dose, making the risk from food acceptable for children and all others in the U.S. population.

Uses Canceled and Maintained

Is it Safe to Eat Fruits and Vegetables?

Yes, the food supply is safe. This action just makes it safer. Parents should continue to feed their children a balanced and nutritious diet rich in fruits and vegetables. EPA's action is focused on reducing risks for the next growing season. It is designed to ensure that the food supply has the extra margin of safety required by the tough new Food Quality Protection Act.

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Additional Protection for Workers

Methyl parathion is hazardous to workers - people who handle or apply the pesticide as part of their occupation, and people who work in fields to harvest treated crops. Protective clothing and equipment are not sufficient to reduce the risks to workers to acceptable levels. By canceling all fruits and many vegetables, workers will be better protected because many of these crops are hand-harvested. By canceling all non-agricultural uses of methyl parathion, risks to certain other workers will also be eliminated.

To increase worker protection for the 2000 growing season, the registrant has increased reentry intervals from two days to four-to-five days. To increase the safety of uses that will continue, for the 2001 growing season, the registrant has agreed to require enclosed cabs and cockpits as well as closed mixing and loading systems. They will also generate exposure studies to resolve outstanding post-application issues.

Ecological Protection

Methyl parathion also poses a high risk to birds and aquatic invertebrates. It is very highly toxic to honey bees. Canceling the orchard uses is expected to significantly reduce risks to honey bees and birds. EPA will consider additional measures for further ecological risk mitigation.

Can Farmers Sell Treated Crops?

Yes. To ensure transition for growers and avoid any disruption to commerce, FQPA includes a "safe harbor" provision that allows legally treated commodities to remain in domestic and international trade.

Timing for Canceled Uses

Existing stocks of methyl parathion products with canceled crop uses may be applied until December 31, 1999. The use cancellations will become effective early next year. Technical registrants of methyl parathion will amend their labels to allow reformulation only to those uses being maintained. Registrants may repackage or re-label their products to reflect only the maintained uses. Application of methyl parathion for the canceled uses will be prohibited for the 2000 growing season.

For Additional Information

Contact EPA's Office of Pesticide Programs at (703) 305-5017, or see our web site, www.epa.gov/pesticides/

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