(CNN) The city of Milwaukee issued a stern warning to residents: Stop vaping immediately.

The advisory came after 16 people were hospitalized with chemical pneumonia, a severe illness that causes lung inflammation, the Milwaukee health department said.

All of them reported vaping or "dabbing" -- inhaling potent marijuana products -- before they were hospitalized, the department said.

The link between vaping and respiratory illness isn't fully understood, officials said, but in the meantime, they're advising residents to stop using vapes, e-cigarettes and liquid THC products. Tetrahydrocannabinol, or THC, is the main psychoactive component of marijuana.

Wisconsin health officials said Thursday they're aware of 32 cases of lung disease, including 11 which are still under investigation.

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