Months after Idaho workers were sickened by pesticides, still more questions than answers

Although the investigation is complete, more questions than answers remain regarding the incident in which farmworkers were sickened by a possible pesticide exposure in a Parma hops field over Memorial Day weekend.

State agriculture investigators said a fungicide called Badge SC sprayed by a crop-duster pilot across the road might have been responsible, but they were unable to definitively prove that the fungicide was the toxic substance that sent the farmworkers to the hospital.

Despite the conflicting evidence and remaining questions, Kevin Kostka, the state’s pesticide compliance manager, sent a regulatory letter to the pilot saying workers were likely exposed to the pesticide he sprayed on an onion field.

“However, based on the proximity of your application to the workers, the experiences detailed by the workers during the interviews, and (Southwest District Health’s) review of the workers’ medical records, the (Idaho State Department of Agriculture) is concerned that some of the workers in the hops field may been exposed to your application of Badge SC,” Kostka wrote in the July 12 regulatory letter sent to José Pérez, the pilot. “Based on the evidence gathered as part of this investigation, the ISDA cannot prove that workers were in fact exposed; however, the potential for drift and human exposure is present.”

Were the farmworkers exposed to a pesticide? Is it allowed in Idaho?

State agriculture investigators say a 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.

Badge SC is used on a variety of crops, including onions. According to the pesticide application label, it’s harmful to humans if swallowed or absorbed through skin and can cause moderate eye irritation. The pesticide is also described as toxic to fish and aquatic insects, with the potential for runoff for several months or more after use.

Workers should be allowed back into the field during the 48 hours after Badge SC is applied only if they are wearing protective gear like chemical-resistant gloves, headgear and footwear, protective eyewear, long shirts and long pants.

The label also states the fungicide should not be used at wind speeds greater than 15 mph, during unstable atmospheric conditions or into areas of temperature inversions. Based on information investigators gathered from Pérez and the nearest weather station, the wind was blowing less than 5 mph when Pérez sprayed the onion field.

However, both Pérez and the farmworkers told state investigators that Pérez flew over the workers, “fast and low to the ground.” Although Pérez stated he turned off his spray when he passed the workers, many told investigators they felt the spray hit them. A few farmworkers who were working closer to the onion field said they felt the spray hit them on the head and upper body “during at least one pass.”

“Many of the workers interviewed commented that they could smell and/or taste the product you were applying,” Kostka wrote in the regulatory letter to Pérez. “Some of the workers said they felt the spray as you entered or existed the application site.”

The fungicide is approved for use in Idaho, but Idaho has no further regulations for Badge SC use other than what is described on the label and included in the EPA’s Worker Protection Standard. The EPA updated the standard in 2015 to prohibit applicators like a crop-duster pilot from spraying within 100 feet of any people.

“That is really hard to police unless you’re there watching it,” Kostka told the Idaho Statesman. “When that regulation came out, the intent was understandable, but it’s a difficult thing to regulate.”

Why couldn’t the state prove the pesticide sprayed by the crop duster made the farmworkers sick?

State agriculture officials identified several “complicating factors” that made it difficult to prove the pesticide from the crop duster is what made the farmworkers sick. First, it started to rain while investigators were still conducting worker interviews, possibly diluting the presence of any other chemicals that may have been found in soil samples. It also made it hard for investigators to identify spray patterns or the blue tint of the suspect pesticide.

“The pesticide at issue here has a blue tint, and that is very visible in the application site,” said Brian Oakey, deputy director at the agriculture department. “If there was any chemical that drifted off site into the hops field, we would have been able to visually observe that, but for the rain.”

Some of the victims also had symptoms that didn’t match with the pesticide sprayed by the crop duster. The first victims taken to the hospital had flu-like symptoms, severe vomiting and stomachaches — symptoms usually associated with an organophosphate pesticide, used on insects.

Cynthia Curl, an assistant professor in Boise State’s department of community and environment health, said there are many types of organophosphates that range in toxicity. Curl did not review the Parma case and spoke in general terms.

“The symptoms of (organophosphate) pesticide poisoning are pretty standard,” Curl said, saying vomiting or stomachaches sounded like common symptoms, too. “They are things like you have tremors, you sweat, cry, urinate. All of the things you would have happen if your nerves never stop firing. Ultimately leading, at worst case, to coma and death. It’s the exact same mechanism by which they are effective pesticides. It’s how they work on insects.”

Investigators could find no record of an organophosphate that would produce those severe symptoms being applied anywhere near the farmworkers at that time.

Badge SC, the fungicide sprayed by the crop duster and that farmworkers told investigators they felt hit them while working in the field, usually causes mild irritation of the eyes, skin and lungs. However, investigators couldn’t get conclusive results that proved the fungicide hit the farmworkers because they didn’t have a lab that could test for Badge SC specifically.

Why couldn’t the Idaho State Department of Agriculture find a lab to test the pesticide?

State agriculture investigators tried to send the clothing and soil samples they collected, including a hat and clothes worn by some of the farmworkers, to eight different labs for testing. None of the labs — four in Idaho, one in Bozeman, Montana, one in Portland, Oregon, one in Yakima, Washington, and another in Brookings, South Dakota — were able to definitively test for Badge SC, which contains copper hydroxide and copper oxychloride.

Oakey told the Idaho Statesman it’s difficult for labs to test definitively for copper-based compounds like Badge SC because many pesticides are copper-based. The state doesn’t have a way to single out Badge SC for testing because of this, and because Badge SC is generally a low-toxicity pesticide.

The Idaho State Department of Agriculture has no plans to further regulate Badge SC beyond the federal regulations, nor to identify a lab or develop a methodology that could exclusively test for the fungicide in the future.

Curl, who studies the effect of pesticides on human health, said the wide range of pesticides approved for use in the United States can make it difficult to set up testing methodology even for the pesticides with higher toxicity to humans.

“It is not uncommon to not have good lab methods for pesticides,” Curl told the Statesman.

What is a regulatory letter? Why didn’t the pilot receive any fines?

The Idaho State Department of Agriculture issued a regulatory letter to the crop-duster pilot, Pérez, at the conclusion of the investigation. A regulatory letter is one of the ways the Idaho State Department of Agriculture enforces and regulates pesticides in Idaho.

Although state investigators couldn’t prove Pérez was ultimately responsible for the farmworkers getting sick, they did conclude he violated Idaho Code 22-3420(8) by applying pesticides in a “faulty, careless or negligent manner.”

There are no associated fines with a regulatory letter. The letter is the second of several options the agriculture department has to respond to pesticide exposures like this one. When investigating pesticide violations, state investigators can choose to issue a letter of warning, a regulatory letter, a notice of violation or assess a civil penalty up to $3,000. They can also refer the case over for criminal proceedings, if necessary.

Unlike with a warning letter, a violator like the crop-duster pilot must respond to a regulatory letter with detailed plans of how he or she will prevent a similar incident or violation from happening again. Investigators consider several factors when deciding penalties. State officials told the Idaho Statesman the inability to find a lab, the mismatched symptoms and that the pilot only violated Idaho Code, not the requirements on the pesticide label, factored into their decision.

Investigators also take into account if the pilot had any previous violations, and Pérez did not. If Pérez doesn’t provide a sufficient answer to state investigators within two weeks, the agriculture department may choose to issue a notice of violation, which could mean the suspension of Pérez’s license to apply pesticides, a civil penalty, or both.

Why was the crop-duster pilot the only one who received any scrutiny? What about the farmers?

Federal and Idaho requirements place the burden of responsibility on the pesticide applicator, in this case the pilot. The pilot applying the pesticide was aware that workers were in the field immediately adjacent to the field he was spraying, Oakey told the Idaho Statesman in an interview, even though he tried to prevent the pesticide from drifting onto the workers.

“Every pesticide applicator has a duty to be careful and to be cognizant and aware of their surroundings and apply it in a manner that is safe, especially when workers are in the area,” Oakey said. “And so that was the regulatory issue that we had with this particular case.”

Although the pilot was not determined to be “negligent,” Oakey said he could have delayed spraying the field until calling the farmers or the labor contractor.

Farmers or operators are only responsible for notifying their own workers that a pesticide will be sprayed in the field they are working in, state officials said. Some pesticides also require field postings, but Badge SC doesn’t have that requirement.

Obendorf Farms, owned by Brock and Phillip Obendorf, and Obendorf Hops, owned by Greg Obendorf are separate companies. While Obendorf Farms owners were not cited for the possible pesticide drift because they notified their workers in the onion field, investigators did find that Obendorf Hops violated a piece of the Worker Protection Standard. During interviews with farmworkers about the pesticide incident, state investigators learned Obendorf Hops had not provided decontamination supplies like soap, water or hand towels.

Those materials should have been provided, state investigators said, because a different pesticide had been sprayed in the hops 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.

Now what?

The investigation is closed, but the agriculture department is following up with the farmers and the crop duster to make sure they are in compliance going forward.

If the pilot doesn’t provide a sufficient response to state agriculture investigators, they may decide to impose a notice of violation or initiate further penalties.

No one has filed lawsuits or initiated further disciplinary action at this time.

The Idaho Statesman is still investigating this incident, as well as general safety issues for farmworkers across Idaho. If you have any information about this incident or would like to talk to a reporter about these issues, email You can also securely send information or tips to our investigative team or email


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Reporter Nicole Foy is helping the Idaho Statesman expand coverage of agriculture, farming and food across Idaho. Agriculture and food production has long been an important part of Idaho’s economy, with dairies, international agribusinesses and food processors among the state’s top employers. Many Idahoans have close ties to agriculture, even as houses continue to replace farmland, especially in Boise and throughout the Treasure Valley.

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