Scientists, state officials and the Army Corps of Engineers are finding the burn zone may not be as toxic as initially feared.
On a sun-drenched January morning, Renee Takesue got down on her hands and knees to dig in Lahaina’s dirt.
The federal research geologist filled containers with soil taken from the mouth of a culvert near the post office. She then crossed Honoapiilani Highway and filled jars with ocean water.
Takesue is looking for harmful contaminants resulting from the Aug. 8 wildfire, things like dioxins, heavy metals, flame retardants and forever chemicals found in firefighting foams and household products.
Her work at 28 sites on land and 10 in the ocean is part of a multi-agency and community effort to understand how the deadly wildfire affected the environment.
It’ll be some time before final conclusions are drawn but early results are encouraging and could hasten Lahaina’s recovery. Just last week state health officials said the ocean around Lahaina is safe for recreation.
Ironically, the preliminary positive news may stem from the fire’s unique alchemy.
Wind-whipped flames that tore through Lahaina on Aug. 8 created an urban fire so hot it not only melted glass, but it appears to have resulted in the complete combustion of many chemicals, rendering them inert.
“The dioxins were not even at levels of concern despite this being a town that burned down,” Takesue said last week.
Molten glass found after the blaze suggests temperatures exceeded 2,700 degrees Fahrenheit. That’s higher than waste incinerators, which usually burn at between 1,800 and 2,200 degrees, according to the U.S. Environmental Protection Agency.
“What happens is that the chemicals either totally volatilize and get transported through the atmosphere or they get destroyed because the temperature is so high,” the U.S. Geological Survey scientist said.
The latest scientific findings mark a big shift from the early days after the fire when many feared that toxins released from burned buildings, cars, boats, gas stations, electrical transformers and fallow agricultural lands may have left behind a dystopian landscape of cancer-causing poisons.
The Lahaina fire killed at least 101 people, destroyed more than 2,200 structures and scorched nearly the same number of acres, many of them former agricultural and grasslands laden with pesticide and herbicide residue.
Many feared runoff would wash into the ocean, contaminating fish and killing the coral reef. The EPA scrambled to spray Soiltac, a soil tackifier, on the toxic ash to keep it in place. Contractors from the Army Corps of Engineers placed absorbent straw tubes around drains to prevent stormwater from entering the sea.
While the data that’s come in offers reason for hope, scientists involved in the monitoring effort say continued sampling and long-term studies are crucial.
Takesue, a California-based researcher, is essentially a scientific detective. Her job is to find out not only what the wildfire left behind as far as environmental contamination, but to distinguish it from pre-fire sources.
The results of her ridge-to-reef sampling get shared with state and other partners, all to understand what may be entering the ocean, where it’s coming from and how it’s potentially affecting sensitive marine ecosystems or human health.
There’s a lot to understand because the fire was both catastrophic and unique.
“It’s not common that entire cities burn down these days,” Takesue said, especially oceanfront ones with many historic buildings constructed before laws prohibited lead in paint and imposed other environmental restrictions.
Takesue said she can’t comment on her specific findings because the Hawaii Department of Health handles public information releases. But generally speaking, what she’s seeing so far is both surprising and encouraging.
The state is cautious about characterizing what it knows so far about the fire’s environmental and public health impacts.
“We agree that the theory of the very hot fire resulting in lower concentrations of chemicals that might typically be found in a fire-related scenario” exists but there’s insufficient data at this point to say conclusively that’s what happened, said Nancy Convard, an environmental engineer and DOH’s wildfires coordinator.
Preliminary data shows very low to non-detectable levels of dioxins and polycyclic aromatic hydrocarbons, or PAHs, indicating no significant human health or ecological concerns, Convard said.
Dioxins and PAHs are persistent carcinogens so the fact that they are appearing in low concentrations, or not at all, is good news for displaced property owners anxious to rebuild their homes.
Kathleen Ho, DOH deputy director of environmental health, said in a news release Thursday that coastal waters around Lahaina are safe for ocean recreation based on results from sampling efforts by university, state and nonprofit researchers.
Residents should still heed brown water advisories as bacterial levels after rainstorms may be high, she said.
Thursday’s announcement about ocean conditions contrasts with earlier DOH advisories.
In December, DOH released data taken a month earlier from 100 properties in Lahaina that revealed elevated levels of arsenic, lead, antimony, cobalt and copper in Lahaina’s ash.
“These data validate that the Lahaina ash contains toxic substances,” Health Director Kenneth Fink said in a news release at the time.
DOH cautioned people to avoid the ocean and urged residents returning to their burned properties to wear personal protective gear and avoid breathing or ingesting ash.
Takesue said it’s not surprising that testing from pure ash samples would come back as they did. The ash was the byproduct of burned materials left behind by the fire.
What’s encouraging is that steps taken to prevent the ash from washing into the ocean, such as Soiltac and the straw tubes around storm drains, appear to have worked as intended. And the fact that high levels of contaminants are not being found in the soils underneath the ash is also a good sign.
As scientific studies and data crunching continue, crews employed by the Corps are actively scraping burned properties in Lahaina of ash and debris, provided owners have signed right-of-entry forms.
Cory Koger, a Corps chemist and subject matter expert, said debris removal crews are also not finding the high levels of toxicity that many expected.
He also subscribes to the theory that many of the Lahaina contaminants simply burned up.
“This fire, with the winds blowing as fast as they were blowing, burned hotter than we have probably seen in any fire,” Koger said.
When it comes to organic compounds like PAHs, released when oil, gasoline, coal and other fossil-fuel substances are burned, the intense heat basically made them chemically inactive.
“Imagine it’s anything organic, like a tree. It basically burns down to carbon. That’s what we’re seeing in the ash,” Koger said. “So, you don’t have that residual compound, whatever it was. It’s now just carbon and carbon dioxide that came off during the burning.”
The lower-than-expected contamination levels are making cleanup efforts go faster than expected.
The Corps crews are excavating ash and debris from the footprint of burned homes and are about a third of the way done. The crews scrape to a depth of 6 inches below the surface and workers collect about 300 sediment samples per property.
The samples are flown to mainland labs where technicians analyze them for a suite of heavy metals, chemicals and other substances. If the levels exceed safety thresholds for residential or commercial properties, the Corps is notified and the crews scrape down another 6 inches.
At a depth of 12 inches, nothing is usually found that’s of concern, Koger said.
“Studies from previous fires show that the impact from the ash is usually 3 to 6 inches,” he said.
So far, less than a quarter of properties have required two rounds of soil removal.
“We have cleared over 550 parcels,” said Koger. “About 20% required additional scraping.”
What Takesue and Koger’s team are finding coincides with other reassuring preliminary data coming in.
Surfrider Foundation’s Maui chapter released preliminary results last week from its water sampling project off Lahaina.
The organization did not find evidence during initial sampling of fire-related contamination that would put human health at risk from ocean recreation, Surfrider said in a blog post.
Concentrations of heavy metals appear to be within the range of typical ocean water levels, and concentrations of PAHs are well below the World Health Organization recreational guidance and drinking water regulations set by both EPA and WHO.
A study being led by University of Hawaii researcher Andrea Kealoha has also released early results that are encouraging although continued vigilance and analysis are needed.
Takesue said low levels of dioxins turned up in some of the Lahaina boat harbor sediment samples collected by the state Division of Boating and Ocean Recreation. But she has determined they originated from legacy agricultural pesticides, not the August wildfire.
In addition to dioxin, DOBOR’s sampling also looked at metals, PAHs, total petroleum hydrocarbons and a list of other organic contaminants. The results showed no significant risk to human health, according to the state health department.
To help the public understand the scientific information becoming available about the fires, DOH has contracted with ERG, an environmental research firm, to build a data portal. The public-facing dashboard will contain available datasets and interpretations of the results.
“There’s desire by the public to know what the science tells us,” Ho said in a recent interview.
There’s not a specific date for when the portal will go live, but Convard said she expects it to happen in the next several weeks.
Civil Beat’s coverage of Maui County is supported in part by a grant from the Nuestro Futuro Foundation.
Civil Beat’s coverage of environmental issues on Maui is supported by grants from the Center for Disaster Philanthropy and the Hawaii Wildfires Recovery Fund, the Knight Foundation and the Doris Duke Foundation.
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