Tests of 1,400 adults linked higher metal exposure to impaired lung function, without proving causation. Participants receive their results and meet with health professionals.
Researchers found elevated concentrations of several toxic metals in Maui adults’ urine six to 18 months after the island’s 2023 wildfires. Higher exposure was associated with impaired lung function, but the findings do not establish that the metals caused those problems or how much exposure came from the fires. Grist reported the findings in an article reproduced by Yale Environment 360 on October 23.
The August 2023 fires killed more than 100 people and destroyed thousands of homes across Maui, including in the town of Lahaina. Earlier research from the University of Hawaiʻi at Mānoa’s Maui Wildfire Exposure Study, published in 2025, found reduced lung function in more than one in five residents.
The new research measured 24 metals in urine samples from 1,400 adults across Maui. Researchers compared the concentrations with those measured in a nationwide health survey conducted before the fires.
| Metal | Concentration relative to comparison level |
|---|---|
| Arsenic | 2.2 times |
| Barium | 2.3 times |
| Manganese | 3.8 times |
The NIH–NASA competition seeks better measurements in laboratory drug-safety models, with submissions scheduled to open on 15 December 2026.
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| Antimony |
| Nearly 40 times |
Antimony is used in flame-retardant materials and has previously been linked to lung irritation, stomach pain and other symptoms. The comparison shows differences in measured concentrations, not how much the fires increased residents’ exposure: researchers lack comparable measurements from Maui before the disaster.
The research considers exposure beyond wildfire smoke. Burning homes, cars and infrastructure can leave contaminants that people encounter for months or years. Researchers also need to distinguish what a fire released from contamination already present in the environment.
Participants receive their individual results, discuss them and meet with health professionals, according to Grist’s account. That gives residents a way to discuss the findings while researchers investigate their origins.
Study codirector Alika Maunakea told Grist that identifying the sources of contamination is the project’s next step. The project has received a $3.6 million grant from the National Institute of Environmental Health Sciences, and the work will examine whether—and to what degree—past agricultural and industrial activity contributed.
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