Officials warn wildland firefighters about the risks of using a supplement for smoke exposure

Fire and medical officials have issued warnings about a supplement offered to Western wildland firefighters who have been exposed to toxic chemicals while battling some of the country’s biggest blazes.

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.

“Because glutathione is not an FDA-approved drug, consumers should be cautious about product safety and claims that glutathione can treat or prevent diseases,” said a safety advisory issued last week by the International Association of Firefighters, a labor union representing some 360,000 first responders.

Warning followed supplement’s use during Spokane wildfires

Glutathione was offered to firefighters during recent blazes that destroyed hundreds of buildings in and around Spokane, Washington. During morning briefings, medical unit leaders on scene from California urged crews to check out a tent where a nonprofit run by licensed naturopathic doctors offered the supplement.

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.

Though there is no evidence to back its use, some firefighters have said the supplement helped them feel better after breathing toxic smoke and they have urged California pharmacy officials not to restrict access.

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.

In response to the safety advisory, Jen Riegle, a naturopathic doctor and co-founder of The Integrative Health Action Network, said the organization recognizes the need for peer-reviewed research on whether glutathione can reduce chemical burdens in firefighters and is “actively exploring partnerships to that end.”

How inhaling wildfire smoke harms the body

More studies are showing the wide-ranging negative health impacts of inhaling wildfire smoke, which is especially toxic when blazes tear through urban areas and burn up household appliances, batteries and chemicals. Tens of thousands of people die annually in the U.S. from long-term impacts of wildfire smoke.

Firefighters work in extreme conditions that make it impractical to use a respirator with an oxygen tank. That means they are exposed to a “slew of chemicals” that have short and long-term impacts on their health, DeCrane said.

Pasadena Fire Captain Matt Caffey, also a paramedic for 28 years, helped fight last year’s Eaton fire in Southern California and said the smoke exposure from burning neighborhoods brings on coughing, vomiting and brain fog.

“You can’t remember things. You’re just so behind the eight ball. You can’t catch up. You’re not recovering,” he said.

Caffey is among the firefighters who say glutathione helps, and he urged Integrative Health Action Network providers to come to Spokane. The California Board of Pharmacy in 2025 reversed course on regulations that would have made the supplement more difficult to acquire after pushback from some firefighters.

Experts say health claims are not backed by evidence

Experts warn anecdotal claims of relief are not proof.

Such claims are “interesting and provocative and deserve further study,” said Dr. Cora Sack, a pulmonary specialist with expertise in environmental and occupational lung disease at the University of Washington School of Medicine. But “we lack clinical evidence of its efficacy.”

Glutathione is an antioxidant made primarily in the liver that neutralizes other unstable molecules that attack the body and cause cellular damage. Wildfire smoke creates oxidative stress in the body, and there is an “interesting biological plausibility” to think antioxidants could impact that, Sack said. But she does not endorse glutathione’s use without clear evidence.

Taking glutathione through a nebulizer may constrict the airways of people who have asthma or chronic lung conditions. Glutathione is processed in sterile compounding pharmacies, and there have been cases of people getting poisoned due to contamination at these facilities, Sack said.

Injecting a contaminated product “could cause significant medical events including fevers, hypotension, inflammatory reactions, anaphylactic shock and death,” according to the recent pharmacy recalls.

Luke Montrose, a professor at Colorado State University whose research focuses in part on the impact of wildfire smoke on disease risk, said glutathione has anti-inflammatory properties.

“But because it hasn’t been studied, I’m hesitant,” he said.

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Andrew Zinin

Master’s in physics with research experience. Long-time science news enthusiast. Plays key role in Science X’s editorial success.

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