Maui County approves using soil stabilizer Soiltac in Lahaina burn area

Maui County has approved the use of the soil stabilizer Soiltac to protect residents’ health and the environment from risks posed by ash and debris that remain on properties burned during the Aug. 8 fire in Lahaina.

The application of Soiltac, a “revolutionary polymer product” of the company Soilworks, can help prevent runoff of hazardous materials to the ocean or nearby streams. It is also used to help reduce inhalation risks and the spread of ash to water on surrounding properties, the county said in a Oct. 9 press release.

Soiltac was utilized to stabilize soil on Kula properties that burned Aug. 8.

“It’s important to protect our community and our air quality and ocean waters from the harm that ash and debris can bring,” Mayor Richard Bissen said in a press release. “With EPA’s review of the product and its recommendation, along with understanding that if we do nothing we will be placing our people and environment at risk, we will proceed with the application of a soil stabilization product.”

According to Soilworks, the key advantage of Soiltac originates with its long, molecular structure that links and cross-links together, allowing stronger bonds to be obtained. After Soiltac is applied and the water disperses from the soil or aggregate, a durable and water-resistant matrix of flexible solid-mass is created. Once cured, Soiltac becomes completely transparent, leaving the natural landscape to appear untouched.

A review of the Soiltac product by the Environmental Protection Agency confirmed the product is non-toxic. Once the liquid product is applied, a crust will form to prevent ash and dust from migrating into the environment. Microplastics from burned plastic materials that are in the ash will also be prevented from migrating, the press release said.

EPA will apply the soil stabilizer to the ash and debris footprints of buildings in Lahaina in coordination with County emergency management officials. The product is not considered to be biodegradable and will be removed as part of the debris removal process conducted by the US Army Corps of Engineers.

But Soilworks said on its website it is biodegradable.

Application of Soiltac will begin as early as next week for properties in re-entry zones and extend to remaining impacted areas. Due to a risk of potential runoff into ocean waters, areas in close proximity to shorelines will be prioritized.

However, in the Frequently Asked Questions supplied by the county about whether residents can opt out of soil stabilizer use on the their properties, it said: “In order to protect the health of residents in and around Lahaina as well as the fragile ocean ecosystem, soil stabilizer will be applied to all properties in Lahaina.”

It also said the EPA considered other soil stabilizer options and considered Solitac to be the best available product.

“Considerations included impacts on flora and fauna (EPA did not want to use a product that would entrap wildlife), the color of the product (it must be clear), toxicity and the availability of technical information for prompt and thorough review.”

According to the Frequently Asked Questions, the EPA said based on observations from applications of the soil, it does not expect any risk to wildlife during the application process.

It said during the applications of Soiltac in Kula, the stabilizer was sticky like painter’s tape for about 20 minutes. The product no longer was sticky after about an hour after application.

According to the Frequently Asked Questions, Soiltac also is commonly used on sites for dust and erosion control.

“It has been used at multiple EPA cleanup sites, including Alameda Point IR Site 2, directly adjacent to the San Francisco Bay, and Iron King-Humboldt Smelter in Yavapai County, Arizona. The California Environmental Protection Agency Department of Toxic Substances Control oversaw the application of Soiltac in a removal action in Fresno, CA.”

It has also been used by the County of San Mateo, Calif., in the construction of a pump track for bicyclists at Quarry Park, a half mile from Half Moon Bay. Soiltac has been used at multiple Olympics in the last 20 years, and in neighborhood parks.

For more information and Frequently Asked Questions, go to: www.mauirecovers.org/recovery/soiltac.