March 10, 2005

Monitoring program evaluated for curbing exposure to pesticide


Dale Dougherty, safety manager for a major Yakima Valley fruit company, described how the state's year-old program to monitor farm workers for exposure to pesticides helped identify an unsafe practice by one of his orchard workers.

The worker was removing a key piece of protective equipment his respirator while spraying orchards last year. He was driving a tractor with an enclosed cab, but it wasn't approved to keep out pesticides. Even though the worker had received extensive safety training, he didn't realize it was not safe to take off the respirator inside the cab while he sprayed pesticide.

Dougherty, speaking Wednesday before a large audience of growers, state regulators and orchard supervisors at the first-ever Agriculture Safety Day in Yakima, said blood tests performed as part of the monitoring program showed the worker had been exposed to a significant amount of pesticide, though he displayed no symptoms or ill health effects.

In response, the company temporarily removed the worker from pesticide spraying duties so he wouldn't be overexposed. Dougherty said they examined his application practices and found the removed respirator. The behavior that led to the exposure was altered, and the problem is gone.

And that's exactly how the program is supposed to function, said Michael Wood, the administrator of the monitoring program, which is run by the Washington Department of Labor and Industries.

Much of the daylong safety seminar that drew more than 300 people to the Yakima Convention Center was given over to discussion of the controversial year-old monitoring program.

L&I monitors farm workers' systems for an enzyme called cholinesterase, which plays an important role in the nervous system. The workers frequently handle two categories of pesticides widely used in orchards: organophosphates, including Guthion, and carbamates, such as Sevin.

The program starts with a baseline blood test at the beginning of the year, before workers handle pesticides. Workers must have an initial consultation with a medical provider, but they're not required to participate in the program. Those who do participate get follow-up blood tests periodically throughout the year, whenever they have handled pesticides for a minimum number of hours in a month. Last year the threshold was 50 hours in a 30-day period; this year it's been reduced to 30 hours.

If the follow-up tests find the workers' cholinesterase levels have fallen by 30 percent or more from the baseline, they are removed from handling the pesticides to avoid over-exposure.

During 2004, which L&I's Stefan Dobratz called "very much a learning experience," 119 of 580 workers who received follow-up tests had cholinesterase depression of 20 percent or greater, which the program deems "significant." Of this group, 22 workers showed depressions of 30 percent or above and had to be removed from work.

Ill health effects associated with overexposure, which don't typically occur until cholin-esterase levels have declined at least 50 percent, include blurred vision, nausea, shortness of breath and, rarely, more serious symptoms. Last year, one worker's cholin-esterase was down 80 percent, but still displayed no outward symptoms.

"I'm not aware of any deaths related to occupational illness, due to use of pesticide in Washington," said John Furman, L&I's technical expert on the monitoring program.

Agriculture industry representatives also point out that the reported cases of pesticide-related illness in Washington have been extremely low during the past four years.

Wood, the program's administrator, said pesticide illness and other maladies incurred on the job is often misdiagnosed.

"L&I is convinced that occupational illnesses are dramatically underreported," he said.

The state consulted with farmers whose workers had significantly depressed cholinesterase to seek causes of pesticide exposure.

Dobratz said in the majority of cases, farmers had safety programs and equipment in place. But workers don't always follow them to a T, and equipment such as respirators may not fit correctly, or may not be cleaned properly after each use.

Unclean equipment is a common way workers are exposed to pesticides. A worker who touches his respirator and then wipes his brow could spread pesticide to his skin.

"We need to think about how we're transferring material from one location to another," said Carol Ramsay, a pesticide safety expert with Washington State University.