Researchers identify situations that can lead to problems
By SEAN ELLIS
A multiyear study by University of Washington researchers found that despite their best efforts to protect themselves, farmworkers who handle or spray pesticides are still being exposed to the chemicals.
The study is based on interviews with dozens of farmworkers and a detailed monitoring effort.
"That suggests to us that the recommendations, at least the way they are applied, may be insufficient for complete protection," said Matt Keifer, senior research scientist with the National Farm Medicine Center in Wisconsin.
"What this tells us is that despite their best efforts to protect themselves, they're still getting exposed," said Keifer, who led the UW study before going to work for NFMC last year.
The university's Pacific Northwest Agricultural Safety and Health Center, which conducted the study along with several other parties, serves Idaho, Oregon, Washington and Alaska.
Researchers used data from a statewide monitoring program that determined pesticide exposure by measuring an enzyme known as cholinesterase.
Though they don't necessarily equal overexposure, lower cholinesterase levels are associated with exposure to pesticides.
Symptoms of pesticide overexposure include vomiting, diarrhea, nausea, headaches and blurred vision. More severe symptoms include seizures and poor respiration, which can cause death.
From a public health perspective, pesticide poisoning is numerically not even close to being the most important farm safety issue, Keifer said. But from a worker's perspective, "pesticides are one of the scariest things on the farm."
It's better to err on the side of caution and do everything possible to minimize exposure, he said.
The UW study, which is ongoing, found that one of the main ways agricultural workers are exposed to pesticides is while they are cleaning equipment used to spray chemicals or while they are mixing or loading pesticides.
Ag workers do a fairly good job of being suited up with the right protective gear while applying pesticides, but many are exposed while washing equipment or mixing chemicals, said Helen Murphy-Robinson, PNASH's director of outreach and education.
"They're not wearing the right protective headgear and glasses and they're getting exposed then," she said.
Researchers discovered that pesticide residue is tracked into the homes of agricultural workers who don't change their clothes or shoes before leaving work.
"Workers who handle pesticides really should have separate clothes," Murphy-Robinson said. "They should change their clothes at work and wear different shoes when they go home so they're not tracking it into their home."
The use of change lockers by pesticide applicators could go a long way toward resolving that issue, Keifer said.
The study found that full-face respirators offered much more protection than half-faced respirators.
Even if a safety label recommends a half-face respirator, "I myself would wear a full-face respirator," he said. "It was clear that worked better."
Murphy-Robinson said researchers placed a fluorescent tracer spray in pesticide tanks to determine where exposure was occurring and found the improper use of gloves was a major problem.
When a spray nozzle gets clogged, many ag workers take off their gloves and use their bare hands to fix the problem, she said. She recommends wearing nitrile gloves under regular ones to minimize exposure.
Disposable nitrile gloves are made of synthetic latex and are more resistant to tearing.
One main cause of pesticide exposure is leather boots, because leather serves as a reservoir for pesticides. The study found that people who wore chemical-resistant boots had far less evidence of exposure.
Drift was another major issue, and researchers found that problem is due to a lack of communication, with sprayers not letting workers in the next field know there is spraying going on.
How to stop exposure
The results of the University of Washington's pesticide exposure research will be included in a booklet, Practical Solutions for Pesticide Safety, which will be released at the end of September.
It is available on the Pacific Northwest Agricultural Safety and Health Center website: depts.washington.edu/pnash
It will include recommendations and practical solutions offered by 95 farmers, applicators and safety educators.
Kit Galvin, the center's senior industrial hygienist, said the recommendations include prewashing and rinsing together in pairs, using a rain hat under a hood, allowing workers to cool off under mixing station showers, using ammunition boxes to store emergency eyewash and using 5-gallon buckets with gallon markings to prevent risky measurements.
Because wind speeds and temperatures can vary significantly over even a short distance, the booklet will also recommend providing applicators with small thermometers and wind meters that provide precise readings.