By Marian Burros

The first detailed scientific analysis of organic fruits and vegetables shows that they contain a third as many pesticide residues as conventionally grown foods.

The findings, published in the Food Additives and Contaminants Journal, confirmed what consumers of organic food have taken for granted but did not settle the argument over whether organic food is safer than conventional food treated with chemical pesticides.

The debate gained prominence in February 2000 when John Stossel, a correspondent on the ABC News program "20/20," reported that testing had proved that the levels of pesticide residues in conventional produce were similar to those in organic produce, making organic claims a fraud. Though Mr. Stossel retracted his statement--such testing had never been conducted--his report alarmed proponents of organic agriculture and those like Consumers Union who do not oppose the use of synthetic pesticides but want stricter standards.

The findings are based on pesticide residue data collected on a wide variety of foods by the United States Department of Agriculture from 1994 to 1999, tests conducted on food sold in California by the state's Department of Pesticide Regulation from 1989 through 1998, and tests by Consumers Union in 1997. The combined data covered more than 94,000 food samples from more than 20 crops; 1,291 of those samples were organically grown, about 1.3 percent.

The Agriculture Department data showed that 73 percent of the conventionally grown foods had residue from at least one pesticide and were six times as likely as organic to contain multiple pesticide residues; only 23 percent of the organic samples of the same groups had any residues.

The California data found residues in 31 percent of the conventional food and 6.5 percent in the organic. Consumer Union tests found residues on 79 percent of the conventional samples and 27 percent on the organic.

The study also looked at why organic foods contained any pesticide residues. When residues of persistent insecticides, like DDT, were excluded, the percentage of organic samples with residues dropped to 13 percent from 23.

The findings were minimized by opponents of organic agriculture, like the American Council on Science and Health, which gets 40 percent of its financing from industry.

"So what?" said the council's Dr. Gilbert Ross. "The health risks associated with pesticide residues on food are not at all established. I think the amount of pesticide residues to which we are exposed on our foods pose no significant health risks to human beings."

The Environmental Protection Agency disagrees and has been working to reduce pesticide levels since 1996.

Dr. Groth said the amount of residues in conventional food was well below the level that is clearly unsafe but above the level scientists say is probably safe.

"There is a large gray area in between," Dr. Groth said, "and we need a wide safety margin which is not wide enough with conventional produce. This is especially true when we talk about infants and children because they are still developing."

Ken Cook, president of the Environmental Working Group, a nonprofit research and advocacy group financed by foundations, said, "The report shows what we suspected all along: if you want to reduce your exposure to pesticides, eating organic is a very good way."

New York Times May 8, 2002