SACRAMENTO — The state has tightened its oversight of pesticide research after finding that researchers working for a French chemical company exposed 19 volunteers to excessive levels of a pesticide that has made farm workers ill, state Food and Agriculture Department officials said Friday.
The researchers, working under contract for Rhone-Poulenc Ag Co., changed procedures that had been approved by the state Food and Agriculture Department and exposed their human subjects to the pesticides for twice as long as should have been allowed, according to an investigation by the Food and Agriculture Department.
The volunteers were picking grapes in a test field sprayed with the pesticide Zolone.
"Without the change, a great many of the people would have been taken out of the field and the study probably would have been ended," Jim Wells, a special assistant in the department's Pest Management Division, said of the Rhone-Poulenc study. "They didn't want to stop the study, so they just amended the protocol."
Neither the company nor the researchers working under contract could be prosecuted because what they did was not covered in regulations in effect at that time, Wells said.
'No Violations of Law'
"There were no violations of law," he said. "We feel it was not really ethical. But we could not find it was technically illegal. All we could do is cry foul."
Ron Hansen, the California representative for Rhone-Poulenc, declined to comment on the report Friday afternoon. He referred all questions to the company's North Carolina headquarters, which were closed for the day.
The research project was conducted in Visalia in August, 1988, after the company, under pressure from the state, stopped selling Zolone, which had poisoned more than 70 workers in grape fields during 1987. The state said the workers in Fresno and Madera counties suffered from headaches, nausea and vomiting.
Rhone-Poulenc was trying to show in the research that its product was safe enough to be used again in the fields.
Under terms approved by the state, the company sent 30 paid workers to pick grapes in fields sprayed with Zolone and 22 to fields that had not been sprayed. The company originally agreed to pull its volunteers from the study if daily blood tests showed excessive pesticide exposure as detected by depressed levels of the enzyme cholinesterase in the blood.
Excessive Exposure Found
But months after the six-day study was completed, the company's report on the research revealed that 19 of the volunteers had been exposed to excess levels of the pesticide but had not been pulled from the fields.
"The study should have been stopped after three days," Wells said.
Although three other participants became ill, doctors monitoring the study for the company determined that none suffered from depressed levels of cholinesterase and none had been overexposed to the pesticide.
In response to the investigation, the state has decided to establish a special board in cooperation with the University of California to approve any pesticide studies involving humans and will require written approval of any future changes in study procedures that have been approved by the state.
Ralph Lightstone, a lobbyist for the California Rural Legal Assistance Foundation, said Friday that he welcomed the increased scrutiny but argued that the Zolone study never should have been approved by the department.
He said the department agreed to the study even though its own research showed that the danger to humans from exposure to Zolone was undetermined. Lightstone said the department should have cleared the study proposal with doctors in the state Department of Health Services.
"No one had any idea what the risks were of exposing these folks, and (the Department of Food and Agriculture) went ahead and approved the study anyway," he said. "Of course, we would like to see the procedures tightened."