Metal mixtures present in the smoke, ash, and debris from the devastating 2023 Maui wildfires have been linked to adverse lung health effects in nearby residents, according to a new study. The research suggests that the long-term consequences of such wildfires, which are exacerbated by climate change, require ongoing monitoring of air quality and consideration of residual contaminants.
The study, published in the journal Proceedings of the National Academy of Sciences, analyzed urine samples from 1,400 adults and revealed substantially elevated concentrations of metals such as arsenic, cadmium, copper, and antimony. These metals may have originated from burned buildings, vehicles, electronics, and other materials destroyed in the fires.
Researchers from the University of Hawaii found that antimony levels were nearly 40 times higher in participants from Maui compared to U.S. biomonitoring data, with manganese 3.8 times higher, barium 2.3 times higher, and arsenic 2.2 times higher. The study linked higher metal concentrations in the body to abnormal lung function, including reduced breathing capacity and difficulty moving air in and out of the lungs, as indicated by standard respiratory tests.
The geographic distribution of these lung effects corresponded with the spread of smoke and ash, with individuals living closer to Lahaina, Wailuku, and Kahului experiencing different impacts than those living near Kula.
"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 professor at the University of Hawaii, Manoa. "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."
The 2023 Maui wildfires, ignited by high winds spreading a brushfire reportedly spurred by downed power lines, decimated the town of Lahaina and resulted in over 100 fatalities, making them among the deadliest in U.S. history.
Experts note that wildfires are becoming larger, more intense, and more frequent in many parts of the world due to warming and drier weather conditions associated with climate change. This trend has led to fires in regions not typically prone to them.
While the study acknowledges a limitation in that it cannot definitively isolate the impact of the wildfires from other potential exposures such as Hawaii's geology, diet, historical land use, and industrial activity, previous research has also documented significant long-term human health impacts from wildfires and other environmental crises. These impacts can include respiratory issues and mental health challenges.
"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," said Dr. Kekoa Taparra, a physician and professor at the University of California, Los Angeles, who was not involved in the study. "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."