Malathion is an organophosphate (OP) insecticide that has been registered for use in the United States since 1956. It is used in agriculture, residential gardens, public recreation areas, and in public health pest control programs. Malathion can be used to kill mosquitoes without posing unreasonable risks to human health or the environment if used in accordance with the rate of application and safety precautions specified on the label. For mosquito control, malathion is applied at a maximum rate of 0.23 pounds (or about 2.5 fluid ounces) of active ingredient per acre, which minimizes exposure and risks to people and the environment. These estimates assume several spraying events over a period of weeks, and also assume that a toddler would ingest some soil and grass in addition to skin and inhalation exposure. However, at high doses, malathion, like other organophosphates, can overstimulate the nervous system causing nausea, dizziness, or confusion. Severe high-dose poisoning with any organophosphate can cause convulsions, respiratory paralysis, and death. Malathion used in mosquito control programs does not pose unreasonable risks to wildlife or the environment. Malathion degrades rapidly in the environment, especially in moist soil, and it displays low toxicity to birds and mammals. Malathion is highly toxic to insects, including beneficial insects such as honeybees. For that reason, EPA has established specific precautions on the label to reduce such risks.

A risk assessment covering all uses of malathion is currently available to the public for review at http://www.epa.gov/oppsrrd1/op/malathion.htm.Visit the EPA Web site (see address below) for the most current information on malathion.