For your ease, here are some of the common questions about Soiltac®:

Why is soil stabilizer being used on Maui?

Applying a stabilization product like Soiltac® prevents health effects from exposure to ash and soot from the wildfire and limits the spread of this material in the community further reducing human exposure. Because it binds the ash and soot it also helps to prevent runoff of hazardous materials to the ocean or nearby streams that lead to the ocean.

In the short term, exposure to ash and soot can lead to respiratory irritation (sneezing, coughing, shortness of breath, hay fever, and asthma attacks for people with asthma), eye irritation (leading to conjunctivitis and enhanced susceptibility to eye infections), and skin irritation (dermatitis). Prolonged exposure increases the risk of heart disease, stroke, lung cancer, chronic obstructive pulmonary disease, lower respiratory infections, and death.

Will soil stabilizer harm wildlife?

No. EPA considered ecological impacts of soil stabilizers when preparing its recommendations. Based on observations from applications of the soil, we do not expect any risk to wildlife. During the applications of Soiltac® in Kula, the stabilizer was sticky like painter’s tape for about 20 minutes. The Soiltac® was no longer sticky after about an hour after application.

Will soil stabilizer negatively affect the environment?

Any potential environmental concerns from the use of a non-toxic soil stabilizer will be vastly outweighed by the benefits of preventing dust and ash from dispersing in the environment.

Can residents opt out of soil stabilizer application?

In order to protect the health of residents in and around Lahaina as well as the fragile ocean ecosystem, soil stabilizer was applied to all properties in Lahaina.

Did EPA consider other soil stabilizer options?

Yes. EPA evaluated a number of options and found Soiltac® to be the best available product for this response. 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.

Has Soiltac® been used elsewhere?

Soiltac® 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 and Control oversaw the application of Soiltac® in a removal action in Fresno, CA (DTSC 2006). It has also been used by the County of San Mateo, California in the construction of a pump track for bicyclists at Quarry Park, which is half a mile from Half Moon Bay. Soiltac® has been used at multiple Olympics in the last twenty years as well as in neighborhood parks. It has also been used by branches in the United States Department of Defense, both internationally and domestically. For any additional information regarding the above uses please visit: https://soilworks.com/reference-library.

How long will the soil stabilizer be effective?

Without disturbing it, soil stabilizer is effective for four to six months.

Is Soiltac® a microplastic? Will it increase the microplastics entering the environment?

The liquid form of Soiltac® proposed for use in Lahaina does not contain microplastics. While the liquid form does meet the federal definition of a plastic [an organic or synthetic polymer liquid that is solid in its final form and is shaped by flow, 40 CFR § 463.2 (f)], once applied the material will form a crust that will prevent ash and dust from migrating into the environment, including microplastics present in the ash as a result of burned plastic materials in the homes. In the event that the Soiltac® is disturbed, either through foot traffic or other physical disturbance, EPA does not anticipate that the crust can break into particles small enough to be considered a microplastics issue. This is also a temporary solution that will be removed from the properties during the Phase 2 ash and debris removal.

Is Soiltac® biodegradable?

EPA does not consider Soiltac® to be biodegradable.
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Soil stabilizer is not intended to be a permanent solution for ash and dust control. It will be removed from properties during the United States Army Corps of Engineers (USACE) phase two debris removal operations.

Is Soiltac® Toxic?

No. EPA has reviewed proprietary data on Soiltac®, and confirms that it is non-toxic.

What does ash and debris look like after it is treated with soil stabilizer?

EPA recommended Soiltac® because it is a transparent and non-toxic stabilizer/tackifier that is commonly used on sites for dust and erosion control. The transparency of the product is important in the context of the Maui Wildfire Response Phase 2 removal effort by USACE, as the ash and debris must be visible to Phase 2 personnel.

When will soil stabilizer be removed?

Treated ash and debris will be removed by USACE during phase 2 operations.