Maui Wildfire Debris Linked to Lasting Lung Health Issues, Study Finds
Researchers discovered elevated levels of metals in residents' urine up to a year and a half after the fires, suggesting long-term health consequences beyond immediate exposure.
Metal mixtures found in the smoke, ash, and debris from the deadly 2023 Maui wildfires have been linked to adverse lung health effects in nearby residents long after the fires ceased, according to a new study published in the journal Proceedings of the National Academy of Sciences. The research suggests that major wildfires, exacerbated by a warming planet, can have lasting health impacts that extend beyond the initial event.
The study, conducted by researchers at the University of Hawaii, analyzed the urine of 1,400 adults and found substantially elevated concentrations of metals such as arsenic, cadmium, copper, and antimony. These metals are likely byproducts of burned buildings, vehicles, electronics, and other materials destroyed in the August 2023 wildfires, which devastated the town of Lahaina, killed more than 100 people, and became among the deadliest in U.S. history.
"What we’re dealing with, especially in the aftermath of what we experienced in Lahaina, is a much more complicated mixture of these chemical exposures," said Alika Maunakea, a co-author of the study and a professor at the University of Hawaii, Manoa. The researchers observed antimony levels nearly 40 times higher in Maui participants compared to U.S. biomonitoring data, with manganese 3.8 times higher, barium 2.3 times higher, and arsenic 2.2 times higher.
These elevated metal levels were associated with abnormal lung function, including reduced breathing capacity and difficulty expelling air, as indicated by standard breathing tests. The study noted that these lung effects aligned with the geographic distribution of smoke and ash, with those living closest to Lahaina and the nearby towns of Wailuku and Kahului experiencing different impacts than those nearer to Kula.
"It’s really important to identify potential sources of these exposures and to mitigate and reduce potential risks for re-exposures that might be contributing to these effects," Maunakea added. "What happens to the land and environment can shape what people breathe, take into their bodies, and develop over time. The consequences of that can unfold over many years."
Experts note that wildfires are becoming larger, more intense, faster-moving, and more frequent globally, partly due to climate change. This trend increases the likelihood of such fires and has led to them occurring in regions not typically prone to them.
The study's authors acknowledged a limitation: they cannot definitively attribute the entire impact solely to the wildfires, as chronic or other environmental exposures—including Hawaii’s geology, diet, historical industrial activities, and agricultural practices—could also contribute. Data from before August 2023 for comparison was unavailable.
However, previous research has also highlighted significant long-term human health consequences from wildfires and other environmental crises, including respiratory problems and mental health issues. Dr. Kekoa Taparra, a physician and assistant professor at the University of California, Los Angeles, who was not involved in the study, stated that the research expands the understanding of the fires' health burden over an extended period. "This type of work echoes that climate-related disasters affect human health well beyond the immediate injuries and deaths we see during the event itself," Taparra said. "As these events become more frequent and severe, understanding and measuring their full health impact will be essential to building more resilient communities and health systems."