BOISE — The Idaho State Department of Agriculture was unable to clearly identify what toxic substance sickened a group of Treasure Valley farmworkers in Parma in May, according to the 248-page report released Friday. However, investigators discovered that a crop duster sprayed a fungicide in a nearby field while the affected farmworkers worked.

The department could not find a lab that could test for the pesticide that might have caused the illnesses, an official told the Idaho Statesman.

The department launched an investigation after reports that several farmworkers were treated for possible exposure to an unknown chemical — causing flu-like symptoms, severe stomach aches and vomiting — at West Valley Medical Center in Caldwell.

State agriculture investigators say a crop-duster pilot employed by Caldwell-based Valley Air sprayed a fungicide called Badge SC on an Obendorf Farms onion field while the affected farmworkers were in an adjacent hops field, owned by Obendorf Hops.

The farmworkers, employed by labor contractor Corral Agriculture, had been working in the Obendorf Hops field just across the road for about five hours when the Valley Air pilot began to spray the onion field.

“At this time, Mr. (Phil) Obendorf was unaware that Obendorf Hops, a separate entity owned by Greg Obendorf, had workers scheduled to be in a hops field neighboring one of the onion fields,” said the summary report.

One of the workers in the field at the time was taken by their spouse to West Valley Medical Center a few hours after the spray. The patient appeared to be suffering from exposure to a different type of pesticide, organophosphate insecticide, and responded to treatment generally used for that pesticide. Corral Agriculture then contacted the other 12 farmworkers who had been in the field and checked them into West Valley for treatment.

Investigators said the Obendorf hops farmworkers were likely exposed to the Badge SC fungicide, but they could not definitively conclude that it was what sickened the farmworkers because of the mismatched symptoms.

An Idaho Department of Health and Welfare review completed June 28 found that copper-containing compounds like fungicide Badge SC are considered to have low toxicity.

“General symptoms of exposure from an aerial spray scenario would be expected to include irritation of the eyes, skin, or lungs,” wrote Morgan Willming, a toxicologist and health assessor for Health and Welfare.

The Department of Agriculture issued a regulatory letter to Valley Air pilot José Perez for his “careless application” of the fungicide.

“Even though he made some accommodations to minimize the potential for spraying the workers, Mr. Perez decided to make his application in a manner that increased the probability for exposing a large group of people to the pesticide, when it was avoidable,” the department’s report states.

Perez has 14 days to respond to the agriculture department’s letter requesting further information about how he will “prevent this violation from reoccurring.” If he does not respond, he will receive a notice of violation and face possible fines or other civil penalties.

“During the ISDA’s investigation, you stated you knew the workers were in the neighboring field at the time you evaluated the wind conditions,” wrote Kevin Kostka, pesticide compliance program manager at the ag department. “Yet, you began spraying immediately afterward. You did not provide the workers any chance to leave or move to an area farther away prior to beginning your application.”

State agricultural investigators also discovered that Obendorf Hops did not provide its workers decontamination supplies such as soap, water or hand towels. Under the Worker Protection Standard, those supplies should have been available as a precaution for workers in the hops field because a fungicide was sprayed in that field the day before.

“The ISDA will follow up with Obendorf Hops to ensure they are meeting the WPS requirements for their own applications,” the report concluded.

Previous Idaho farmworker illness incidents

The state agriculture department regulates the registration, sale, distribution, use, storage and disposal of pesticides. The agency is also charged with implementing the EPA’s Agricultural Worker Protection Standard program, which aims to prevent pesticide-related injury or illness.

The last case of a large group of Idaho farmworkers becoming ill was a 2005 pesticide exposure, according to department records. In that case, 29 farmworkers were sickened by a mixture of three pesticides — Lannate, Mustang Max and Dithane DF — that was applied to a Caldwell field about 4.5 hours before the workers began weeding, according to a 2005 Statesman article.

State agriculture investigators determined there had been a breakdown in communication that resulted in the chemical exposure, and they imposed a total of $40,000 in fines to those involved, including the farmer, labor contractor and the pilot who applied the pesticides. The farmworkers in that case told investigators that they had not received training about pesticides, as required by state law.

A Statesman review of pesticide complaints during the five years prior to the 2005 incident showed that pesticides drifting on to nearby fields was the main reason why farmworkers were exposed to the chemicals.

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