When Professor Andrew Whelton first heard about the wildfires on Maui, he immediately knew the island would face a major challenge to ensure the safety of drinking water.

“The community was experiencing something that other people have experienced elsewhere and I was concerned for their safety,” said Whelton.

A professor of environmental and ecological engineering at Indiana’s Purdue University, Whelton is one of America’s leading experts on the impact of wildfires on water systems. He flew to Maui last week and began collaborating with researchers Chris Shuler and Aurora Kagawa-Viviani from the University of Hawai’i at Manoa. They’re taking samples, working to help people understand water safety and conducting surveys to understand their experiences.

UH-Manoa will analyze the chemical testing results, which will take at least two weeks.

With a focus on environmental chemistry and engineering, disasters and water quality, infrastructure and public health, Whelton previously provided guidance to authorities on Oahu dealing with the Red Hill fuel leak, which contaminated drinking water. He was also called on to help with the 2017 Tubbs Fire and 2018 Camp Fire in California, and the 2021 Marshall Fire in Colorado.

Before his research, studies had primarily focused on how wildfires’ high temperatures degrade plastic, causing chemicals to be released into the air. Whelton and his students found evidence suggesting that heat-degraded plastic pipes can also leach hazardous chemicals into drinking water. These chemicals are known as volatile organic compounds, and they are often toxic and not easily detected by color or odor. Since the Tubbs Fire, labs have identified more than 50 volatile organic compounds that can be found in drinking water after wildfires. These include benzene, toluene, naphalene, methylene chloride, ethylbenzene and xylene.

Recent testing results released by the state Department of Health detected benzene in one Lahaina sample and the presence of toluene and xylenes in one Kula sample.

“They are not always present in the same systems,” Whelton said. “Sometimes some are present and others are not. That’s why you have to throw the book at the water system to figure out what exactly is present. Then you narrow down your list of what you test for, so you can test faster and test more frequently.”

For Kula, Whelton cautions that water filters may not do the trick.

“I wouldn’t necessarily try to filter the water, thinking that it would make it safe, because we know from work that we conducted after the Camp Fire that filters are not designed to remove really extreme contamination, which can be found,” he said.

Following the Camp Fire in the town of Paradise, benzene levels in the drinking water reached 2,217 parts per billion, far exceeding the U.S. Environmental Protection Agency’s standards of 5 ppb for chronic exposure. Two years after the Camp Fire, households were still receiving drinking water advisories. At 153,336 acres, the Camp Fire was far larger than Maui’s fires, which burned more than 2,000 acres in Lahaina but the Lahaina fire has already been more deadly.

The Kula sample contained far lower levels of toluene and xylenes at less than 0.5 ppb. Still, Whelton’s research of wildfire contamination has found that water needs to be tested over and over again before it’s deemed safe. He said he would be “very cautious about using the water for anything except for toilet flushing activities.”

“Sometimes when you have wildfires, like the Camp Fire, and it burns through an entire town, you have widespread destruction. That is more similar to Lahaina,” Whelton said. “Kula experienced different types of damage. In some cases, it was sporadic. Then there’s the Olinda fire. We went to where the Olinda fire was believed to be started today, and we tested buildings around that area, and that too seems to be a very complex water system.”

“The reason why I bring this up is because this fire disaster response, when it comes to water, seems to be more complex than others that we have responded to,” Whelton added. “It’s an amalgam of all the different types of damage that a water system can have.”

He advised that residents talk to an agronomist or somebody skilled in agriculture and irrigation when it comes to the safety of watering gardens and irrigating farms.

“We’ve seen elsewhere that irrigation lines have been damaged by fires in the past, and people sometimes have chosen not to use them, or simply replace them out of concern that they didn’t want to contaminate their own gardens or crops,” Whelton said.

Lahaina faces a massive challenge in terms of cleanup. Whelton has said in previous interviews with other news outlets that the soil, air and water at the harbor are all contaminated, requiring major debris removal. Following Colorado’s Marshall Fire, which destroyed more than 1,000 homes, 300,000 tons of debris was removed.

“The Camp Fire disaster required Paradise to collect thousands of water samples and it cost over $800,000 just in sampling costs alone, not repairing it, just knowing where the contamination was,” Whelton said. “Then you have to flush it if it’s a low-level contamination. It will take weeks to months, or you could remove and replace and dig up the pipes. Paradise had to replace 16,000 service lines because the majority of them were contaminated.”

Following a Kula community meeting on Thursday, Whelton added that there is not enough data to make any decision about the safety of water in upper Kula.

“I would say to be cautious in how they use the water,” he said Friday in advice to Kula residents. “We still don’t really understand the degree of contamination in the water systems because there haven’t been enough samples yet.”