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# Maui Study Links Persistent Metal Exposure to Impaired Lung Function
- URL: https://www.theamericanquorum.com/maui-study-links-persistent-metal-exposure-to-impaired-lung-function/
- Published: 2026-09-29T08:27:41.000Z
- Updated: 2026-09-29T08:27:41.000Z
- Description: A new study of 1,400 Maui adults found unusually high urinary metal levels months after the 2023 wildfires, with combined exposure associated with impaired lung function. The findings deepen the case for long-term post-disaster health monitoring.
- Author: Kenneth R. Deans Jr.
- Tags: Healthcare, Hawaii

Antimony concentrations in urine from 1,400 Maui adults were roughly 40 times the U.S. biomonitoring comparison level six to 18 months after the August 2023 wildfires, according to a peer-reviewed [study](https://doi.org/10.1073/pnas.2613208123?ref=theamericanquorum.com) published Monday. The researchers also found higher combined exposure to a mixture of metals was associated with abnormal lung function, adding biological evidence to concerns that an urban wildfire can leave health risks long after smoke clears and debris is removed.

The University of Hawaiʻi-led Maui Wildfire Exposure Study measured 24 metals in urine and assessed pulmonary function during the same visit. Antimony showed the largest difference from U.S. reference data; manganese was 3.8 times higher, barium 2.3 times higher and arsenic 2.2 times higher. Arsenic, cadmium, copper and antimony were among the metals most strongly contributing to statistical patterns tied to impaired breathing, according to the paper and an independent account by the [Associated Press](https://apnews.com/article/c7ea730977c8e11aece702a58ab1d898?ref=theamericanquorum.com).

The findings do not prove that wildfire contaminants caused any participant’s lung impairment. There were no comparable urine measurements from before the fires, and Maui residents can encounter metals through local geology, diet, past agricultural and industrial activity, smoking, occupations and other environmental sources. The work is nevertheless consequential because it connects three parts of the exposure chain in the same population: metals inside the body, objective breathing tests and the geography of smoke and ash from one of the deadliest U.S. wildfires in more than a century.

## An urban fire creates a different chemical mixture

Wildland-urban interface fires do more than burn vegetation. Buildings, vehicles, batteries, electronics, plumbing, paint and household materials can release metals and other toxic substances when they burn, while heat, cleanup and wind can remobilize older contaminants in soil and dust. That makes the post-fire environment chemically more complicated than a plume produced mainly by trees and brush.

Maui’s environmental record supports the plausibility of that pathway, although it cannot establish how much of the metals detected in participants came from the fire. Hawaiʻi health officials sampled ash from 100 Lahaina properties in November 2023 and reported elevated arsenic, lead, antimony, cobalt and copper in the [ash](https://health.hawaii.gov/news/newsroom/lahaina-ash-characterization-testing-show-elevated-levels-of-toxic-substances/?ref=theamericanquorum.com). The buildings represented construction eras spanning more than a century, a detail that matters because the materials consumed by the fire varied widely.

Federal cleanup records show the scale of potential sources. The Environmental Protection Agency removed more than 200 tons of hazardous material from over 1,400 properties and collected more than 30 tons of lithium batteries from vehicles and energy-storage systems, according to its [cleanup record](https://www.epa.gov/maui-wildfires/hazardous-materials-removal?ref=theamericanquorum.com). Crews then applied a soil stabilizer to ash and debris footprints to limit windblown dust and runoff. Those actions reduced exposure opportunities, but they did not provide a measure of what individual residents had already inhaled, swallowed or otherwise absorbed.

## What researchers measured inside the body

The new study used urinary biomonitoring, which can detect elements excreted from the body after recent or continuing exposure. The underlying laboratory approach, inductively coupled plasma mass spectrometry, is also used in the federal National Health and Nutrition Examination Survey. Federal [laboratory methods](https://wwwn.cdc.gov/nchs/data/nhanes/public/2017/labmethods/UM-J-MET-508.pdf?ref=theamericanquorum.com) describe it as a trace-level technique for evaluating environmental or non-occupational exposure to metals including antimony, barium, cadmium and manganese.

That national survey supplied the comparison data used to show how unusual several Maui measurements were. But a biomarker is not a dose reconstruction. Urine concentrations vary with hydration, timing, metabolism and the chemical form of an element, and one sample cannot reveal exactly when or where exposure occurred. Arsenic is a particularly important example because seafood can raise total urinary arsenic through organic forms that carry different toxicity from inorganic arsenic; interpretation depends on whether and how researchers account for speciation and diet.

To avoid leaning on one statistical model, the investigators evaluated metal mixtures through three complementary approaches. The consistency of the association across those models strengthens confidence that the pattern is not simply an artifact of a single analytic choice. It still remains an observational association, however. The study measured metal burden and lung function at the same visit rather than randomly assigning exposure or following each participant from a verified pre-fire baseline.

## The lung findings fit an earlier warning

The metal analysis builds on earlier work from the same community cohort. A 2025 [JAMA study](https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2837319?ref=theamericanquorum.com) of 1,174 adults found that 150 of 670 participants with valid measurements, or 22.4%, had below-normal forced expiratory volume in one second. People living within the fire perimeter had lower predicted FEV1 and forced vital capacity than those outside it after adjustment for demographic, socioeconomic and preexisting health factors.

Forced expiratory volume measures how much air a person can force out in the first second of a breath; forced vital capacity measures the total volume exhaled during the maneuver. Lower values can reflect obstructive or restrictive problems, but spirometry by itself does not identify a single disease or cause. In the earlier study, acute exposure was strongly associated with self-reported respiratory symptoms, while residence inside the perimeter was associated with reduced measured lung function. The new analysis adds a potential biological pathway by showing that internal metal mixtures were associated with abnormal pulmonary results.

The geographic pattern also matters. Researchers reported differing effects among participants near Lahaina, Wailuku and Kahului compared with those near Kula, broadly aligning with the distribution of smoke and ash. Geography can still capture more than fire exposure, including housing, employment, traffic, soil, diet and access to care. It is therefore supportive evidence, not a source fingerprint.

## Why reassuring air data do not settle the question

Hawaiʻi’s long-running air program collected more than 1,000 samples during debris removal and found nearly all metal concentrations were extremely low and below health-protective levels. The state’s [monitoring data](https://health.hawaii.gov/environmental-data/air/metals/?ref=theamericanquorum.com) identified two short-lived exceptions in August 2024, when manganese and nickel rose at one site and manganese rose at another, but officials could not determine the source.

Those results are not necessarily in conflict with the biomonitoring study. Outdoor monitors measure airborne concentrations at particular places and times. Urine reflects what entered a person’s body through potentially multiple routes, including inhaled dust, ingestion and occupational or household contact. Exposure could also have occurred before routine monitoring began, indoors, away from a monitor or during brief episodes that daily averages did not capture.

The distinction is central to disaster-health surveillance. An air-monitoring program is designed to detect hazardous ambient conditions and guide immediate protective action; a cohort study asks what has accumulated in people and whether it tracks with health. Neither can substitute for the other. Global health guidance has long identified fine-particle wildfire smoke as a threat to the lungs and cardiovascular system, but the [WHO](https://www.who.int/health-topics/wildfires?ref=theamericanquorum.com) evidence base is much stronger for acute smoke exposure than for years-long effects of metal mixtures from burned communities.

## Limits keep the result from establishing causation

The missing pre-fire baseline is the study’s largest limitation. Without knowing participants’ earlier metal levels and pulmonary function, researchers cannot measure within-person change attributable to the disaster. Participation in a community cohort may also differ from a random sample of Maui residents: people with symptoms, greater exposure or stronger community connections may be more likely to enroll. Residual confounding remains possible even after statistical adjustment.

Metal toxicology also varies by compound, dose, route and duration. The federal [toxicology profile](https://www.atsdr.cdc.gov/toxprofiles/tp23.pdf?ref=theamericanquorum.com) for antimony describes respiratory effects in occupational and animal studies, but evidence from a post-disaster community at lower, mixed exposures is more limited. A urinary concentration above a national comparison does not by itself diagnose poisoning, predict future disease or establish that treatment is needed. Clinical interpretation requires an exposure history, repeat testing where appropriate and assessment of symptoms and organ function.

The strongest conclusion is narrower: this cohort carried an unusual internal mixture of metals months after the fires, and higher mixture levels were associated with impaired pulmonary measurements. The agreement with ash testing, prior lung findings and the spatial pattern makes continued investigation reasonable. It does not identify a single culprit or quantify how much risk remains today.

## A longer timetable for health recovery

For Maui’s health system, the immediate implication is sustained surveillance rather than a new diagnosis for every resident. Repeat biomonitoring and spirometry could show whether metal levels decline, remain elevated or predict changes in lung function over time. Comparing exposed residents with carefully matched populations elsewhere in Hawaiʻi would help separate wildfire effects from island-wide geology, diet and background exposures. Children, cleanup workers, people with asthma and residents who repeatedly encountered dust may warrant particular research attention because their vulnerability or exposure could differ.

The policy lesson extends beyond Maui. Disaster response usually measures deaths, injuries, smoke and short-term air quality, while recovery programs focus on debris removal and rebuilding. The new findings suggest that urban-fire protocols may also need planned, multiyear human biomonitoring, linked clinical follow-up and data systems capable of distinguishing environmental exposure from housing disruption and gaps in care.

Three years after the Lahaina disaster, the evidence now reaches beyond reports of symptoms: researchers have measured a persistent metal burden and found it travels with objective breathing abnormalities. Whether those metals came predominantly from the fire, whether the associations represent lasting damage and which interventions reduce risk remain unanswered. Longitudinal follow-up, not a single cross-sectional snapshot, will determine whether the signal fades with recovery or marks a durable public-health consequence of fires that consume towns as well as forests.