Elevated mercury and lead levels in the blood cells of firefighters who fought blazes across swathes of Los Angeles in January reveal the unique health risks of fighting fires in populated areas where buildings, cars, and electronics outnumber trees.
For days after they had fought the fearsome Pacific Palisades and Eaton fires, some firefighters had extremely high lead and mercury levels in their blood, reports the New York Times.
According to the L.A. Fire Health Study, the urban firefighters had blood lead levels “five times higher” than baseline levels in those who battle forest fires where the primary fuel is trees. The urban firefighters had levels of mercury triple those found in their wildland firefighting peers.
Launched this spring, the study of the health impacts of smoke and other pollutants from the California wildfires will span 10 years.
That the lead and mercury—both known neurotoxins—were found in the firefighters’ blood cells, not just their plasma, “alarmed” research lead Kari Nadeau, chair of the environmental health department at the Harvard T.H. Chan School of Public Health.
The toxins were able to breach cell walls, which means they could have “come into contact with cellular DNA, potentially causing short- and long-term health consequences,” Nadeau told the Times.
The firefighters are being treated at the Cedars-Sinai Medical Center and researchers will be following them over time to track any longer-term health outcomes.
The research team is also working to track the health of local residents and measure “how well, or poorly, interventions like masks and household air filters protected them,” the Times writes.
The data set shared by Nadeau is preliminary and small, but wildfire smoke expert Minghao Qiu, an assistant professor at the School of Marine and Atmospheric Science at Stony Brook University in Long Island, New York, who was not involved in the study, said the research breaks new ground in measuring toxins within the bodies of firefighters— rather than just in the surrounding air.
Further research will be needed to determine how the lead and the mercury ended up in the firefighters’ blood—whether through inhalation or some other path like absorption through the skin, he added.
“The recent findings highlight the many unrecognized, cascading health effects from climate-intensified wildfire,” said Jennifer Runkle, an environmental epidemiologist at the North Carolina Institute for Climate Studies, who also was not involved in the study.
“There is a hidden human cost that we have yet to measure effectively—one that lingers beneath the surface and has long-term health consequences for both firefighters and exposed communities.”
