County Tests Children for Reaction to Malathion : Pesticide: Substance is applied to skin of volunteers to determine whether it can provoke allergic responses. Opponents say long-term dangers are too poorly understood to conduct study.

The county Department of Health Services has begun an experiment this month that involves applying malathion to the skin of children volunteers to determine whether the pesticide can provoke an allergic response in human beings.

Only a small amount of malathion is being used on the children and health officials say the worst they expect to see is minor skin reddening and possibly some swelling.

Health officials say the experiment is one of only about a dozen human studies that have been directly drawn from the California malathion spraying experience and thus is a critical link in understanding the effects of the aerial campaign on the public.

But anti-malathion activists, still angry and afraid over the spraying battle against the Mediterranean fruit fly, are calling the experiment an irresponsible foray into the world of weird science.

Patty Prickett, coordinator of the anti-malathion group Residents Against Spraying Pesticides, said she believes the long-term dangers of malathion are too poorly understood to expose children, whatever the dose.

“I can’t believe they’re exposing kids all over again to malathion,” Prickett said. “My kid will not be a guinea pig, he’s been a guinea pig long enough.”

The experiment involves a standard allergy test in which patches of malathion, fly bait and a mixture of the two are placed on the skin of a subject. Researchers also are using a so-called “scratch” test in which a subject’s skin is pricked with diluted concentrations of malathion.

No child is being exposed to more than 11 milligrams of malathion--about the same as what was sprayed on six square feet during the state’s aerial campaign against the Medfly.

“The amount is minuscule,” said Kim Woloshin, the county health official coordinating the study. “There is a head lotion for lice that has more malathion in it.”

The department already has conducted tests on a group of about 30 adult volunteers, who were drawn from a list of people who complained of rashes, hives, swelling and other allergic symptoms because of malathion spraying. No subject showed any reaction beyond skin reddening and some swelling.

“I really don’t think we’re putting children at risk,” Woloshin said. “The hardest part is having the kids sit there for 20 minutes.”

The child study has been approved by a scientific panel from UCLA charged with reviewing human experiments at the university. All the children’s parents have given permission to join the study.

Woloshin said the experiment is an important component in resolving one of the most persistent questions in the malathion debate: whether the pesticide was to blame for the numerous complaints of rashes and other allergy-related problems.

“If there are people who are allergic to the spraying, this is important information to know,” Woloshin said.

Kathleen Rodgers, an assistant professor at the USC School of Medicine who has spent nearly a decade studying the effect of malathion on the immune system, said that, as with other chemicals, there are unknowns concerning malathion’s effect on humans. More than 1,000 scientific studies about malathion have been conducted, but there remains a degree of controversy over the pesticide’s long-term effects, such as whether it causes cancer or birth defects.

“There is no scientific basis to say there are going to be problems, but there’s no basis to say there aren’t going to be problems either,” she said.

Anti-malathion activists, about a dozen of whom gathered in West Los Angeles Friday to protest the “scratch-and-patch” tests, say the experiment puts the children at unnecessary risk in the light of these uncertainties.

Dr. Kenneth P. Stoller, a Burbank pediatrician, said: “I don’t think we can say whether malathion is as harmless as what the state has adamantly maintained. The point is that a known toxic chemical is being used on children who cannot give their own informed consent.”

Woloshin, of the Department of Health Services, said the children’s parents were contacted because they had filed reports of health problems for their children during malathion spraying. The details of the experiment were explained to the parents, who were required to sign a consent form.

Woloshin said the experiment should be completed by early next year.

The county released last week the results of urine analysis tests conducted on 67 people who reported health problems related to malathion spraying.

The study found no traces of malathion in any sample, but did detect substances in 12 samples that are formed when malathion is metabolized in the body.

Woloshin said the levels of these malathion metabolites were 10 to 100 times lower than previously estimated, indicating that far less malathion enters the body than had been expected. The samples came from people who were outside during aerial spraying or later touched something covered with malathion.

A fourth human study proposed by the department involved “spritzing” adult subjects with malathion in a sealed chamber to determine the pesticide’s effect on asthmatics.

The experiment is on hold while the department searches for the $120,000 needed to conduct the study.