The University of Hawaii analyzed urine from about 1,400 residents near the August 2023 Maui wildfires and found elevated levels of metals — including antimony, manganese, barium and arsenic — up to 18 months later. These higher metal burdens were associated with abnormal lung function and tracked with local smoke and ash exposure. Researchers say metals likely came from burned buildings, vehicles and electronics, and they urge longer-term air-quality monitoring and cleanup of residual contamination. The study is limited by the lack of pre-fire baseline data, making it hard to fully separate wildfire impacts from other local exposures.
Maui Wildfires Left Toxic Metal Mixes — Study Links Elevated Metals To Lasting Lung Damage
FILE - A man views the aftermath of a wildfire in Lahaina, Hawaii, Aug. 19, 2023. (AP Photo/Jae C. Hong, File)(AP Photo/Jae C. Hong)
A new study finds that metal mixtures present in smoke, ash and debris from the August 2023 Maui wildfires were associated with lasting respiratory harm among nearby residents. The research, published in the Proceedings of the National Academy of Sciences, suggests contaminants from burned buildings, vehicles and electronics persisted in people’s bodies and were tied to abnormal lung function up to 18 months after the fires.
Study Design and Methods
University of Hawaii researchers analyzed urine samples from roughly 1,400 adults who lived near the affected areas of Maui. They compared measured metal concentrations with U.S. biomonitoring reference data and assessed lung function using standard breathing tests. The team also examined geographic patterns of smoke and ash to link exposures with health outcomes.
FILE - Charred vehicles remain near burned homes in the aftermath of a wildfire in Lahaina, Hawaii, Aug. 22, 2023. (AP Photo/Jae C. Hong, File)(AP Photo/Jae C. Hong)
Key Findings
The researchers found substantially elevated concentrations of several metals associated with respiratory harm. Compared with U.S. reference levels, study participants showed:
- Antimony: nearly 40 times higher
- Manganese: 3.8 times higher
- Barium: 2.3 times higher
- Arsenic: 2.2 times higher
- Elevated levels of cadmium, copper and other metals were also observed.
Higher body burdens of these metals were linked to abnormal lung function — including reduced breathing capacity and impaired airflow on standard spirometry tests. The pattern of lung impairment tracked with local smoke and ash distribution: residents nearest Lahaina and in areas such as Wailuku and Kahului experienced different impacts than those nearer to Kula.
FILE - The remains of homes are visible in the aftermath of a wildfire in Lahaina, Hawaii, Aug. 22, 2023. (AP Photo/Jae C. Hong, file)(AP Photo/Jae C. Hong)
"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 and professor at the University of Hawaii, Manoa.
Sources, Limitations and Implications
Investigators say the metals likely originated from burning of man-made materials — building materials, vehicles, electronics and other infrastructure — rather than vegetation alone. That creates a distinct exposure profile that can pose different and longer-lasting health risks.
The study notes an important limitation: without pre-fire baseline biomonitoring data, researchers cannot completely separate exposures caused directly by the wildfires from chronic or historic local sources such as geology, diet, past agricultural or industrial activity. Despite this, the findings align with mounting evidence that major climate-driven disasters can create persistent environmental contamination and prolonged health burdens.
FILE - A person pushes a cart along the Honoapi'ilani Highway past homes destroyed by a recent wildfire in Lahaina, Hawaii, Aug. 21, 2023. (AP Photo/Jae C. Hong, File)(AP Photo/Jae C. Hong)
"This is bigger than wildfires. These climate-related disasters can change the environment in ways that continue after the immediate emergency is over," said Ruben Juarez, a co-author and professor of health economics at the university.
Authors and outside experts recommend extended post-fire air-quality monitoring, targeted cleanup of contaminated soot and debris, and recovery planning that addresses long-term environmental and health impacts. The study underscores the need to include legacy contaminants in disaster response and community health planning.
Reporting note: The research was published in the Proceedings of the National Academy of Sciences. Alexa St. John of The Associated Press reported on the study. The AP's climate and environmental coverage receives foundation support; AP is solely responsible for content.
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