Nearly nine out of 10 cases where vaping led to people developing a severe lung disease in Wisconsin involved the use of THC products, such as waxes or oils, Wisconsin’s Department of Health Services said Thursday.

Health officials said that 89 percent of the 27 people they interviewed who became sick reported using e-cigarettes or other vaping devices to inhale THC, the psychoactive compound in marijuana.

“Vaping cartridges containing THC may include chemicals or additives that are unknown, unregulated, and unsafe,” Department of Health Services Secretary-designee Andrea Palm said in a statement. “We strongly urge people not to vape.”

Health officials said despite the finding they’re still investigating all possible causes for why people became ill with “severe chemical pneumonitis, or chemical pneumonia.” Officials say it’s an inflammation of the lungs due to inhaling irritants. Health officials say they’re also working with the FDA to determine the contents of vaping products the people used.

No deaths have been reported in Wisconsin but Illinois reported the first death in the country related to vaping last week.

Wisconsin health officials called the investigation “complex and ongoing” and said investigators “are working to gather information about the products used, collect products for testing, and investigate new cases.”

There have been nearly 200 illnesses related to vaping in at least 22 states, according to the Centers for Disease Control and Prevention.

Wisconsin health officials said they’re still interviewing new patients as part of the investigation. The department said there are currently 32 cases, with 11 patients who need further investigation to determine the cause of their illness. The 32 cases include confirmed and probable cases, the health department said.

The patients who became ill all reported vaping in the weeks and months prior. Symptoms from the disease include shortness of breath, fatigue, chest pain, coughing, and weight loss.

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