ABC News spoke with LA Fire HEALTH Study researchers Dr. Kari Nadeau and Dr. Susan Cheng last night on ABC News PRIME about their research into the health impacts of exposure to toxins in wildfire smoke in firefighters.

Dr. Kari Nadeau, chair of the Department of Environmental Health at Harvard T.H. Chan School of Public Health, published a new study today in Nature Medicine which examined the level of toxins in firefighters’ blood following wildfires in Northern California. The study found that exposure to smoke may alter the immune system on a cellular level, and is the first to examine the specific cellular changes associated with fire smoke exposure, documenting how smoke can damage the body through the immune system.

“We’ve known that smoke exposure causes poor respiratory, cardiac, neurological, and pregnancy outcomes, but we haven’t understood how,” said corresponding author Kari Nadeau, John Rock Professor of Climate and Population Studies and chair of the Department of Environmental Health. “Our study fills in this knowledge gap, so that clinicians and public health leaders are better equipped to respond to the growing threat of difficult to contain, toxic wildfires.”

The same methods used to examine the firefighters in that study are now being used to monitor the health of first responders and citizens in LA following the January 2025 fires in Eaton and Palisades.

Dr. Susan Cheng, Erika J. Glazer Chair in Cardiovascular Health and Population Science and Director of Public Health Research at Cedars-Sinai Hospital, is currently researching those health impacts. She told ABC News, that she and her colleagues are already seeing patients in their emergency rooms and clinics who have experienced impacts to their health due to wildfires.

Watch the ABC News story here: