More than 300,000 farm workers may be victims of pesticide poisoning each year because federal and state laws are too weak and too poorly enforced to protect them, a Washington-based research center reported yesterday.

The World Resources Institute said its analysis found that 40 years of trying to control the dangers of pesticides has produced a "regulatory muddle" that has increased health risks to field hands and farmers instead of reducing them.

Even in California, which has the toughest pesticide-control laws on the books, "reported poisoning incidents have risen an average of 14 percent a year since 1973, and field hands currently suffer the highest rates of occupational illness in the state," the institute said.

According to the report, part of the problem stems from the replacement of older pesticides, such as DDT, banned because of its persistence, with newer products that break down more easily in the soil but are more toxic.

Despite the new products' greater toxicity, little data has been gathered on poisoning rates or human exposure, and the Environmental Protection Agency (EPA) is "flying blind" on setting safety standards for farm workers, the report said.

"It is a sad irony that we've corrected one environmental problem and have tended to exacerbate another -- the question of farm worker safety," said Richard Wiles, who wrote "Field Duty: U.S. Farm Workers and Pesticide Safety" with Robert Wasserstrom.

The report also criticized the EPA's emphasis on protective clothing for farm workers, rather than more stringent safety measures. According to the authors, sophisticated infrared studies show that even "impermeable" rubber gloves do not prevent pesticides from getting on the skin.

The report recommends stronger provisions to protect farmers and field hands, including longer waiting periods before farm workers can reenter sprayed fields and more vigorous enforcement of pesticide-control laws.

According to the study, enforcement patterns have shifted significantly under the Reagan administration, with civil and criminal prosecutions dropping by more than half.

The report also urged that the EPA be required to do more research into pesticide exposure and health effects, "so they'll know how . . . many people get cancer and where and under what conditions," Wasserstrom said.

But the authors said more fundamental changes may be necessary to correct what they called the "endemic overuse" of pesticides in U.S. agriculture. American farmers use about 2.3 billion pounds of pesticides each year -- one-third of the world market -- and critics have long contended that thousands of tons are used against pests and diseases that are not a threat.

"Perhaps 50 percent of pesticides applied are superfluous," Wasserstrom said. "It's the insurance mentality: If five applications are good, 10 applications are better."