White hotel sits next to burned trees and buildings next to a beach
Maui County has taken preventative measures to keep potentially toxic stormwater runoff from entering waters off the coast of Lāhainā following the Aug. 8 wildfire that devastated the historic town. Photo courtesy Hawaiʻi DLNR

Maui County has taken preventative measures to keep potentially toxic stormwater runoff from entering waters off the coast of Lāhainā following the Aug. 8 wildfire that devastated the historic town. Photo courtesy Hawaiʻi DLNR

Maui residents have been manifesting rain, but this actually may be harmful to the waters surrounding Lāhainā. On Aug. 8, a wildfire damaged or destroyed most of the town, including more than 2,200 structures — 86% of which were residential. In the midst of hurricane season, there is concern over potentially toxic sediment runoff, which naturally occurs after heavy rains.

“You really have this toxic soup,” said John Starmer, chief scientist at the Maui Nui Marine Resource Council and regular MauiTimes contributor. “You’ve got heavy metals, you’ve got the residuals of burned plastic, you’ve got all the chemicals that anybody had in their household plus industrial chemicals — all that sort of stuff was burned in an uncontrolled environment.”

The biggest issue here is the unknown: Not only is it difficult to determine what toxins may be in the runoff, there’s also very little research on short- and long-term effects since this is not a common occurrence, according to Starmer.

As post-tropical storm Fernanda approached Hawaiʻi late Sunday night, the National Weather Service announced that it anticipated rainfall in the windward and mauka areas of Maui through Tuesday morning.

In an effort to reduce runoff, the U.S. Coast Guard installed absorbent booms at eight storm drain outfalls that connect the impacted areas of Lāhainā to the ocean. Emergency response crews also deployed inlet protection devices at all street-level storm drain catch basins, according to a Maui County news release.

The Aug. 20 press release was transparent about the fact that these preventative measures may not be enough. This sentiment was echoed by Starmer, who said these devices can effectively hold back larger chunks of debris, but potentially harmful chemicals will likely still seep through.

Potential negative effects may include a “poisoning effect” on marine life from exposure to the likes of copper or other heavy metals, decreased oxygen levels as well as bacterial and algae blooms, according to Starmer.

“The way to sum it all up is that you are throwing a whole bunch of toxins into the environment. Each of them may have a very different effect on a single organism, but it’s sort of like you’re hitting them from multiple different directions, which is not going to be good for the overall well-being of anything in the water,” he said.

Starmer also pointed to human health risks, as these toxins “tend to accumulate in the food chain.”

Once these materials get into the ocean, Starmer emphasized that they are incredibly difficult to regulate. “All of the environmental organizations I’ve spoken to … [are asking], ‘How do we keep it on the land?’ ” he said. “It’s not great on the land, but it’s much better … than letting it get into the water because you’ve lost control at that point.”

Starmer also noted that the Environmental Protection Agency has made efforts to spray a “binder across contaminated areas to hold everything together” and keep potential toxins on the land until it can be disposed of properly.

If toxins do make it into the ocean, they also run the risk of being spread across a large area due to the strong currents in Lāhainā. This dangerous water quality could affect shorelines from Kāʻanapali all the way to Olowalu Landing, and Maui County has advised beachgoers to stay out of brown water in those areas.

Starmer and other environmental stewards are now pushing for funding to get water tested now in order to have a baseline for further research.

Additionally, landscapes that have been impacted by the Aug. 8 wildfires are at an increased risk for flooding due to the decrease in surrounding vegetation. The possibility of flash flooding, mudslides and unstable roadways will increase, even in areas that are not typically considered high-risk, according to a Maui County press release.

As of publication, the National Weather Service’s forecast for Lāhainā includes scattered showers, mainly before 9 p.m., with a 30% chance of precipitation Aug. 21, as well as isolated showers and a 20% chance of precipitation through Monday, Aug. 28.

Hawaiʻi’s hurricane season runs through Nov. 30, according to the National Oceanic and Atmospheric Administration (NOAA), which has predicted more cyclone activity than usual due to it being an El Niño year.