The Environmental Protection Agency is responsible for approving pesticides that are sold. An EPA pesticide fact sheet dated November 1987 on sumithrin contains no information on the acute or chronic toxic effects when it is swallowed, absorbed through the skin or sprayed in the eye. Nor is there any information on whether sumithrin causes birth defects, genetic damage, is poisonous to birds or how it behaves in soil or water. However, numerous independent studies of synthetic pyrethroids do not give these chemicals a clean bill of health. Synthetic pyrethroids, a class of more than 1000 broad-spectrum insecticides, are the most commonly used chemicals for indoor pest control.
Studies have also shown various synthetic pyrethroids can harm immune and reproductive systems.
Dr. Philip Landrigan, chairman of the Department of Community and Preventative Medicine at the Mt. Sinai Medical School in New York City, says the average U.S. medical student gets only about six hours of training in environmental medicine in four years of medical school, and almost none of that focuses on pesticide toxicity. In order to work, the insecticide must hit the mosquito directly, says Dr. David Pimentel, an insect ecologist at Cornell University. But since spray trucks are only fogging the street side of buildings, he doubts that more than one-tenth of 1 percent of the poison is actually hitting its target. None of the dozens of stories reviewed for this piece mentioned there are much safer and more effective alternatives for dealing with adult mosquitoes. Prevention works best and is the least toxic way to control mosquitoes.