The supplement glutathione, given through an IV or an inhaler-like machine called a nebulizer, has not been proven to be safe or effective and could expose firefighters to illness if there is contamination while it's produced, experts say.

At least two pharmacies recalled the supplement in August due to bacterial contamination found during testing at their labs, with one saying it had received reports of people suffering from fever, chills, severe headache and other symptoms.

A group of naturopaths called The Integrative Health Action Network had previously provided the supplement to firefighters during the January 2025 wildfires that tore through Los Angeles County. The group’s work with firefighters began following a 2017 blaze that destroyed thousands of homes in California’s wine country.

The supplement's promotion in Spokane prompted physicians and some members to contact the IAFF with concerns about health claims despite no research proving those claims or showing the supplement's safety, said Sean DeCrane, IAFF assistant to the general president for health and safety. Some doctors have warned of adverse effects.

The IAFF also received reports saying some firefighters felt worse or became sick after getting treated. Medical treatments being marketed to firefighters should be evaluated and tested to make sure there are no unintended consequences, DeCrane said.