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National Alert

Illegal Use of Methyl Parathion Insecticide

The Agency for Toxic Substances and Disease Registry (ATSDR) and the federal Environmental Protection Agency (EPA) are jointly issuing an alert to the general public warning of an emerging national pattern of illegal use of methyl parathion, an agricultural insecticide approved only for outdoor use. When used in homes to kill roaches and other indoor insects, the insecticide can cause serious health problems in people and their pets.

Consumers should be aware that some unlicensed pest control operators are illegally spraying methyl parathion. Such illegal use has been found in the following locations:

In 1994, serious contamination of homes and businesses with methyl parathion was discovered in Lorain County, Ohio. Through the Superfund program, EPA decontaminated 232 homes to habitable conditions at a response cost of more than $20 million.
In April 1995, a similar incident was discovered in Detroit, Michigan. Four residences including a neighborhood homeless mission, required decontamination and restoration at a cost of approximately $1 million.
In November 1996 in Jackson County, Mississippi, ATSDR and EPA discovered that more than 1100 homes were contaminated over a 2-year period. This incident may end up costing more than $50 million.

In each incident, methyl parathion was found at levels that could have harmed human health; therefore, residents were relocated until their homes could be decontaminated. Residents reported flu-like symptoms, diarrhea, headache, nausea, and dizziness.

What is methyl parathion?

Methyl parathion, also known as "cotton poison," is a man-made pesticide that should only be used in open fields to control insects. It is commonly used on cotton, soybeans, and vegetables. Related to nerve gas, this chemical is a brownish liquid that turns milky white when mixed with water. Methyl parathion smells like rotten eggs and can leave a yellow stain on areas where it has been sprayed.

Are there other names for methyl parathion?

Methyl parathion has been marketed under the following product names: Nitrox; Penncap-M; Dithon 63; Ketokil 52; Seis-Tres 6-3; Metaspray 5E; and Paraspray 6-3.

How can methyl parathion affect my health?

If you are exposed to methyl parathion or other toxic pesticides, you may have headache, nausea, dizziness, anxiety, chest tightness, blurred vision, and restlessness. Symptoms that might mean an exposed person's condition is getting worse include muscle twitching, weakness, tremor, lack of coordination, excess sweating, abdominal cramps, vomiting, and diarrhea.

Severe exposure can lead to convulsions, unconsciousness, cardiac arrest, and death. People who are exposed to significant amounts over time may have a persistent lack of appetite, weakness, and malaise. Swallowing, inhaling, and having skin contact with methyl parathion are all ways in which people can be exposed. Children, the elderly, and people with certain health problems are especially at risk.

Does methyl parathion affect the health of animals?

Cats and dogs may be easily exposed to methyl parathion when they come in contact with contaminated surfaces such as floors. Because of their small body weights, exposed pets may quickly show signs of methyl parathion poisoning. Illness in pets after a pest control application can be a first warning that an illegal pesticide has been used. Exposed animals have the same health effects as people.

Helpful Tips

If you hire someone to treat your home for a pest problem, be sure to use the services of a pest control expert. Make sure that any person you hire is licensed and certified to apply pesticides. Ask to see the certification. Also ask for the brand name of the pesticide and the name of the product's active ingredient. This information is important if you or your family react to the product.

If you buy over-the-counter pesticide products to apply yourself, be sure the product is in unopened, original pesticide containers that are labeled and contain an EPA registration number.

If you feel you have been exposed to methyl parathion or feel sick after a pesticide has been used in your home, consult your doctor or local poison control center.

Important Telephone Numbers

Agency for Toxic Substances and Disease Registry (ATSDR) Emergency Response Hotline (24 hours): (404) 498-0120
ATSDR General Information: 1-888-422-8737
Pesticide Information Telecommunications Network (PITN): 1-800-858-7378
National Animal Poison Control Center: 1-800-548-2423
National Response Center: 1-800-424-8802

For further information, contact:

ATSDR Emergency Response Section
404-498-0249

Related Information

ATSDR ToxFAQs: Methyl Parathion

ATSDR Methyl Parathion Expert Panel Report

EPA Press Release

CNN - Homeowners worried after pesticide misuse - Nov. 18, 1996

CNN - Clean-up to begin for residents sickened by toxic pesticide - Nov. 20, 1996

Updated by R. Searfoss October 31, 2003
For more information, contact ATSDR at:
1-888-422-8737 or e-mail: atsdric@cdc.gov (public inquiries)