The contaminated waste includes a unique Hawaii building material made of sugarcane fiber and termite poison.
Authorities don’t know how contaminated Lahaina is, but past wildfires show destroyed urban areas are strewn with hazardous waste that can complicate the remediation process.
“The amount of debris generated from major disaster events, on the low end, maybe five to 10 times annual waste-generation in a given community,” said Nazli Yesiller, director of the Global Waste Research Institute at California Polytechnic State University.
When a wildfire burns, safe everyday household items — cleaners, electronics, appliances, batteries, and vehicles — release heavy metals, chemicals and noxious substances into the air.
Once settled, those contaminants taint the debris, ash and soil left behind in a wildfire’s wake.
Immediate exposure to these toxic substances can cause anything from skin irritation to troubled breathing and vomiting. Over time they can lead to cancer or death.
In addition to predictable substances, Lahaina’s debris contains a unique Hawaii building material that harbors its own risk.
Canec — pronounced cane-ick — was a fiberboard made from sugarcane fibers and treated with arsenic as a termite repellent. Structures dating between the 1930s and 1960s used the building material in load bearing walls and ceilings, according to David Cerame, a project manager and restoration specialist with Architects Hawaii Ltd.
Officials are also concerned about asbestos and lead paint in Lahaina.
According to a survey of property histories, 9% of the affected area in Lahaina was built when canec was in use, and nearly half the buildings predate the 1978 federal ban on lead paint.
Standard soil tests will not capture the full scale of contamination, according to Andrew Whelton, a professor of engineering at Purdue University. He has consulted on targeted testing in wildfires like the 2021 Marshall Fire in Colorado.
“You have to explicitly identify what you’re looking for in the soil,” Whelton said. “People just need to be very careful about interacting with their environment because it can pose an immediate health risk.”
In the case of canec — with its high concentrations of arsenic — immediate exposure to its particles may be relatively harmless, but repeated inhalation and ingestion could be harmful to longterm health.
Returning residents and clean-up crews also have to be cautious around concentrated byproducts like polycyclic aromatic hydrocarbons — or PAHs. These petroleum-derived chemicals are normally emitted in open air environments by cars and burning plastic.
When access was restored to Lahaina, DOH recommended returning residents wear N95 masks which can filter out dangerous particulate matter that may be in the air.
Grace Simmons, program manager for the Department of Health’s Hazard Evaluation and Emergency Response, said the department is developing more advisories for appropriate personal protective equipment.
The first phase of Lahaina’s cleanup is underway to remove hazardous household waste — visible items including propane tanks, partially intact asbestos, ammunition, pesticides and batteries.
EPA Incident Commander Steve Calanog estimated this will last eight to 12 weeks once the search for remains and cultural artifacts is finished.
EPA crews equipped with radiation, carbon dioxide, mercury and other detection equipment will survey each property for work conditions and contaminants. A second team then removes the flagged waste, posts a clearance sign and an online map will be updated with that location.
After clearing a property, crews administer a soil tackifier to glue contaminated ash and soil to the ground.
“The islands, in particular Maui, have these strong leeward winds and and we recognize that there are potential receptors, humans, the ocean and marine environment, that we want to mitigate further continued impacts,” said Calanog.
The collected debris will be packed into barrels and yard boxes, then temporarily stored at Ukumehame Shooting Range, just south of Lahaina.
Large debris will then be loaded into shipping containers on a vessel bound for three likely landfills on the mainland.
Calanog said the final destinations have yet to be determined.
The question of how contaminated soil and ash collected in the second phase will be disposed of remains open.
Yesiller, of the Global Waste Research Institute, said contaminated soils are often landfilled because the cost of bioremediation to break down the pollutants is too high. However, local landfills are typically not designed for a sudden high-volume influx of hazardous waste, she said.
Maui County operates four county-owned landfills, six closed landfills, and landfills over 250,000 tons of waste each year, according to the Solid Waste Division’s website.
County officials could not be reached to clarify Maui’s landfill capacity and future plans for soil remediation.
Past wildfires like the 2018 Camp Fire lend insight into how long the land remediation process can take.
That fire razed more than 18,000 structures in Paradise, California, and remediation cost more than $1 billion and lasted over a year. A similar cost and timeline for Lahaina remediation has been quoted by U.S. Sen. Brian Schatz.
California also created a standard for post-wildfire recovery that is now being applied in Maui after California Gov. Gavin Newsom deployed 101 state and local government personnel, including three experts on wildfire debris and hazardous waste removal.
The process includes crews testing and excavating concrete foundations down to the first 3-6 inches of soil.
Civil Beat reporter Jake Indursky contributed to this story.
Civil Beat’s coverage of Maui County is supported in part by a grant from the Nuestro Futuro Foundation.