Scientists Warn of Toxic Particle Pollution in Maui Wildfire Smoke

Scientists and health officials in Maui County, Hawaii on Monday urged residents to stay away from the island's western coast if possible to avoid exposure to potential toxins that may have been released following the wildfire that killed at least 96 people and destroyed the historic town of Lahaina.

Officials have not determined exactly what toxins were released as last Tuesday's fire tore through the island and exposed an estimated 86% of Maui's 2,719 structures to the flames, but officials have taken note that a wide array of buildings and objects were burned by the fast-moving wildfire.

"When you burn people's belongings, vehicles, and boats, we don't necessarily have a good understanding of what those chemicals are," Andrew Whelton, director of Purdue University's Center for Plumbing Safety, told the Associated Press on Monday. "When much of that infrastructure burns, it's transformed into other materials that are never meant for human contact."

Hawaii state toxicologist Diana Felton is helping to assess the damage and told Hawaii Public Radio (HPR) on Saturday that the U.S. Environmental Protection Agency and other federal officials will work to remove propane tanks and other clear hazards from Lahaina and the surrounding area.

"It's going to be a long time" before the devastated town is safe for people without protective gear, she said.

On social media, Whelton said that based on previous fires and the toxins that have been released, authorities will need "at least three months, possibly longer," to remove wildfire debris and that soil testing will be needed afterward.

In addition to propane tanks—one of which created a cloud that looked like a "gigantic mushroom" when it exploded in the fire, as a resident told the AP—officials have raised alarm about lead paint and asbestos in the historic buildings that went up in flames, as well as arsenic, which was used in the last century as an herbicide on some sugar and pineapple plantations and may have been released when an estimated 2,170 acres burned last week.

At The Conversation, Whelton wrote Saturday that chemicals including benzene and polycyclic aromatic hydrocarbons are frequently detected in ash following large wildfires. Exposure to high levels of those toxins can cause nausea, vomiting, dizziness, rashes, and respiratory problems.

Whelton told the AP that anyone entering the area is advised to wear protective gear that covers their arms and legs as well as a well-fitting face mask such as an N95.

"If you go back into some zones even where maybe all the fires have been put out, you can then be really exposed," he said. "If there's dust and debris kicked up, you can get it in your eyes, on your hands, or you can inhale it."

The county issued an "unsafe water" alert for parts of Lahaina and the Kula district, warning that tap water could have contaminants even after being boiled. Residents who are not among the 46,000 people who fled the island should rely only on bottled water for cooking and drinking.

"Strange things can happen to the water," Felton told HPR. "I'm optimistic that the water system will be able to be restored, but until we have a better sense of how much, if any, contamination is present, we won't have a timeframe on that."

The safe drinking water branch of the Hawaii Department of Health told HPR that it's planning to conduct testing on drinking water across western Maui.

The Maui fire is just the latest to raise alarm about the after-effects of wildfires, which scientists say are becoming more common and harder to get under control due to environmental factors like dry vegetation and long droughts, driven by the climate crisis.

Earlier this year much of the eastern U.S. was placed under air quality alerts as smoke from wildfires in Canada drifted to the region, raising the risk of exposure to particulate matter pollution, which is linked to heart and lung disease.

One 2017 wildfire in Northern California, which destroyed about 1,200 structures, generated 300,000 tons of debris that included toxic levels of arsenic, cadmium, copper, lead, and mercury.

"In Maui, debris may have to be taken off the island for disposal," Whelton wrote.

Maui County Mayor Richard Bissen told residents in a press conference Saturday that at this point "it is not safe" to return to the parts of the island affected by the blaze.

"We're not doing anybody any favors by letting them back in there quickly, just so they can get sick," he said.