Maui study finds metal levels linked with lung-function differences

The story in brief

What you need to know

• The researchers measured metals in urine, an indicator of internal exposure, rather than relying only on outdoor air samples. The study reports higher levels of several metals than in US reference data from 2011–12; it did not have pre-fire measurements from the same participants to show how their levels changed.12
• The association with lung function concerned the combined metal mixture: greater mixture burdens were linked with greater odds of abnormal spirometry across the study’s models. The findings do not identify a single metal as the cause of the results.1
• Hawaiʻi’s Department of Health says most of its more than 1,000 post-fire air samples showed metal concentrations that were extremely low and not harmful to health. It recorded two exceptions, involving manganese and nickel at two sites on 25 August 2024.3
• A separate state screening of 557 West Maui residents in 2023–24 found no evidence of widespread elevated blood lead levels. That screening focused on lead in blood, so it did not measure the same metals or exposure indicator as the later urine study.41
• The study’s authors note limits including community-engaged, rather than population-based, recruitment and the use of spot urine samples. They also say urinary arsenic may partly reflect diet. These limitations affect how the results can be interpreted and applied to residents beyond the cohort.1

Conservation context

Why this matters

The findings add evidence about internal metal measurements and lung function after the fires, while leaving the source of the measured burden unresolved. The air monitoring and lead screening provide relevant context, but examine different measures and cannot directly settle the source of metals found in urine.134

The developing story

What happens next

The questions raised by the reporting include whether repeated biomonitoring and lung-function assessments would show changes over time, and how much of the measured burden is linked to fire-related exposure. The study and accompanying coverage do not quantify the contribution of different sources.125

Established evidence

What we know

• The cohort comprised 1,400 adults enrolled six to 18 months after the August 2023 fires.12
• Urinary levels of several metals were reported as higher than US reference data from 2011–12.1
• Higher combined metal-mixture burdens were associated with greater odds of abnormal spirometry; the study was cross-sectional and does not establish cause and effect.1
• State air monitoring found most sampled metal concentrations extremely low and not harmful to health, with two reported site exceptions in August 2024.3

Open questions

What we don't know

• There were no pre-fire biomarker measurements from the study participants to establish how their individual metal levels changed after the fires.1
• The study cannot determine how much of the measured metal burden came from the fires rather than pre-existing contamination, geology, diet or other environmental sources.125
• Because recruitment was community-engaged rather than population-based, the findings may not describe all Maui residents; how representative the cohort is remains uncertain.1
• The available findings do not establish whether exposure levels or the association with lung function persist, change or diminish over time.12

Source coverage

Read the reporting