Mixtures of metals found in leftover smoke, ash and debris Maui’s deadly wildfires in 2023 were harmful to the lung health of people living nearby long after the fires had subsided, a new study suggests.
The work shows that major forest fires, which are worsen with global warmingcould have lasting effects beyond immediate exposure.
Air quality after a wildfire needs to be monitored over the longer term, the research suggests, and recovery efforts need to take into account what might remain in contaminated soot, residue and dirt long after the burning stops.
Wildfires, sparked by wind spreading brush fire caused by downed power lines, burned on the Hawaiian island of Maui in August 2023, destroyed the town of Lahaina and killed more than 100 people. They were among the deadliest in the history of the United States.
New research published Monday in the journal Proceedings of the National Academy of Sciences found higher metal levels, associated with respiratory disorders, in nearby residents up to a year and a half after the fires.
Researchers at the University of Hawaii studied the urine of 1,400 adults and found significantly elevated concentrations of metals such as arsenic, cadmium, copper and antimony.
Burning buildings, cars and electronics can release harmful chemicals
Charred vehicles remain near burned homes following a wildfire in Lahaina, Hawaii, August 22, 2023. (AP Photo/Jae C. Hong, File)
These metals could be the result of buildings, vehicles, electronic devices and other materials burned in wildfires, researchers say. They may have a different human impact than simple burned vegetation that is typically studied after fires of this magnitude.
“What we’re dealing with, particularly as a result of what we experienced in Lahaina, is a much more complex mix of these chemical exposures,” said Alika Maunakea, study co-author and professor of anatomy, biochemistry and physiology at the University of Hawaii at Manoa.
Researchers found antimony levels nearly 40 times higher in Maui participants than U.S. biomonitoring data. They found manganese 3.8 times higher, barium 2.3 times higher, and arsenic 2.2 times higher.
According to the study, having more metals in the body was more likely to lead to abnormal lung function, such as reduced breathing capacity and difficulty moving air in and out of one’s lungs, during standard breathing tests.
These pulmonary effects corresponded to the geographic distribution of smoke and ash; those closest to Lahaina, as well as Wailuku and Kahului, experienced a different impact than those near Kula.
“It’s really important to identify the potential sources of these exposures and to mitigate and reduce the potential risks of re-exposures that could contribute to these effects,” Maunakea said. “What happens to the land and environment can shape what people breathe, take into their bodies and develop over time. The consequences can ripple over many years.”
Global warming could make forest fires worse
The remains of homes are seen following a wildfire in Lahaina, Hawaii, August 22, 2023. (AP Photo/Jae C. Hong, file)
Forest fires are get bigger, more intense, faster and more frequent in some parts of the globe, experts say, in part because of warming and drier weather associated with climate change. Human-caused climate change has increased the probability many major fires around the world in recent years and caused fires in the regions who don’t usually see them as often.
The researchers noted a limitation of the study in that it cannot assess exactly how much of the impact comes directly from wildfires versus chronic or other exposures — such as geology, diet, Hawaii’s historic agricultural and industrial activity, and environmental sources — given that comparable data does not exist until August 2023.
However, previous studies have also shown significant long-term human impacts linked to wildfires and other environmental crises. Impacts include lung problems and mental health problems such as depression.
“This is more serious than wildfires. These climate-related disasters can change the environment in ways that will continue after the immediate emergency has passed,” said Ruben Juarez, co-author of the study and professor of health economics at the university. “Floods, hurricanes, fires and other disasters can certainly disrupt the soil, debris, buildings and legacy contaminants that we have in Hawaii, creating these exposure pathways. … Disaster response should not stop when the visible danger is gone.”
A person pushes a cart along Honoapi’ilani Highway past homes destroyed by a recent wildfire in Lahaina, Hawaii, August 21, 2023. (AP Photo/Jae C. Hong, File)
Dr. Kekoa Taparra, a physician and assistant professor who studies chronic diseases at the University of California, Los Angeles, said the research expands our understanding of the health burden of fires, especially over a prolonged period of time.
“This type of work echoes the fact that climate-related disasters affect human health far beyond the immediate injuries and deaths we see during the event itself,” said Taparra, who was not involved in the study released Monday but has studied the health impacts of disasters. “Historic wildfires in Lahaina and even Los Angeles have highlighted how these disasters can have longer-term consequences due to displacement, disruption of health care and social networks, environmental exposures and potentially increased mortality.
“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. »
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Alexa St. John is a climate reporter for the Associated Press. Follow her on X: @alexa_stjohn. Contact her at (email protected).
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