A Washington state jury decided Monday that Monsanto should pay $857 million to former students and parent volunteers who said they were exposed at a school to dangerous chemicals made by the company and then fell ill, according to court records.

The Seattle Superior Court jury said Monsanto must pay $73 million in compensatory damages and $784 million in punitive damages to five students who had attended the Sky Valley Educational Center in Monroe, Washington, northeast of Seattle, and two parents who had volunteered there.

The former students and their parents said they had become ill from chemicals known as polychlorinated biphenyls, or PCBs, that had leaked from the school’s light fixtures, according to Henry Jones, an attorney for the plaintiffs. The chemicals in the accessories were manufactured by Monsanto, which Bayer bought in 2018.

The verdict, which will be reviewed by a judge, would add to billions of dollars in similar amounts awarded by juries that have troubled Bayer in the years since its acquisition of Monsanto.

Jones said in an email Monday after the verdict: “No one who has heard this evidence would ever trade places with any of these people for all the money the jury awarded.”

Monsanto said in a statement Monday that it planned to appeal to overturn the verdict and challenge the “constitutionally excessive damages awarded.”

“The objective evidence in this case, including blood, air and other tests, demonstrates that the plaintiffs were not exposed to dangerous levels of PCBs, and that PCBs could not have caused their alleged injuries,” the company said.

The plaintiffs include former students and parent volunteers who were at Sky Valley Education Center starting in 2005, according to court documents. They claim they suffered neurological, neurophysiological, endocrine and autoimmune problems after being exposed to chemicals at school, according to court documents.

The Monroe School District, which includes Sky Valley Education Center in Washington state, did not immediately respond to requests for comment Monday afternoon.

PCBs were once regularly found in commercial products and industrial equipment, such as lighting, until they were banned in the United States in 1979 amid concerns that they harmed people and the environment, according to the Environmental protection agency.

Products that include PCBs are no longer commercially produced in the United States, but the chemicals may still be present in products manufactured before their ban, according to the EPA.

Conclusive evidence has found that PCBs can cause cancer in animals, as well as harm their immune, reproductive, nervous and endocrine systems, according to the EPA. The chemicals have been classified as “probably carcinogenic” to humans, according to the agency.

Since Bayer bought Monsanto, the company has faced costly legal battles over concerns about chemicals produced by Monsanto, such as the herbicide Roundup.

Bayer agreed to pay $10 billion in 2020 to settle claims that Roundup caused cancer, one of the largest settlements of its kind. The company has said it has set aside an additional $6 billion for ongoing lawsuits and others that could be filed later.