After Nearly a Decade, Officials Are Still Defending Malathion

Malathion, a commonly used garden pesticide, has been the main weapon of state agricultural officials in their battle to eradicate the Mediterranean fruit fly in California.

But after nearly 10 years of aerial spraying, its use remains controversial--at least among residents in neighborhoods where malathion is released.

State and federal health officials maintain that malathion is one of the safest pesticides available. They point to numerous studies, including a recent report that found no increased incidence of birth defects or any lowering of birth weights in three San Francisco Bay Area counties during widespread spraying there in 1981-82.

Although malathion could be harmful if swallowed in large doses, toxicologists say the pesticide poses no health hazard because extremely low amounts are used in aerial spraying. Paul Papanek, chief of the county Department of Health Services toxics epidemiology program, said the aerial dispersal of two to three ounces of malathion per acre “means that you just can’t ingest enough to cause any health problems.”

“If malathion is causing any health problems, we can’t find them,” he said.

During aerial spraying in the Bay Area in 1981, B. T. Collins, Gov. Edmund G. Brown Jr.’s director of the California Conservation Corps, drank a glassful of diluted malathion to demonstrate that it is harmless.

Malathion belongs to a family of pesticides called organophosphates that attack the nervous system. The pesticide is used commercially to kill pests on more than 150 crops, to control malaria mosquitoes and to kill head lice. In homes, it is used to get rid of fleas on dogs and cats, and to kill common plant pests. Its primary manufacturer is American Cyanamid Co.

The state Department of Food and Agriculture studied data compiled by chemical companies to support malathion’s licensing as a pesticide in 1987 and concluded that there was only one major area of concern, a study that indicated Malathion could cause ulcer and gastric inflammation in rats.

But Jay Schrieder, a toxicologist for the state agency, said that the rats were repeatedly exposed to very high doses of malathion and that the chemical would pose no threat to humans.

Some residents, however, have complained of nausea after aerial spraying. More often, they cite damage to their cars’ paint jobs. State officials say sticky corn syrup added to attract the flies and make the chemical adhere to the ground is the real culprit.