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Lahaina News – Use of soil stabilizer Soiltac approved (TPD2310026)

Use of soil stabilizer Soiltac® approved for burned properties in Lahaina

By Staff | Oct 10, 2023

Application of Soiltac by U.S. Environmental Protection managed field teams will begin as early as next week for properties in re-entry zones and extend to remaining impacted areas. Treated ash and debris will be removed by the U.S. Army Corps of Engineers during Phase 2 operations.


WAILUKU — Mayor Richard Bissen announced he 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 impacted by the Aug. 8 fire devastation in Lahaina.

The U.S. Environmental Protection Agency (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 U.S. Army Corps of Engineers.

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.

The application of a stabilization product like Soiltac can help prevent exposure to ash and soot by preventing 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.

Soiltac was utilized to stabilize soil on Kula properties affected by the fire disaster.

“It’s important to protect our community and our air quality and ocean waters from the harm that ash and debris can bring,” said Mayor Bissen. “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.”

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.

For more information and Frequently Asked Questions (FAQs), visit www.mauirecovers.org/recovery/soiltac.

A letter from the EPA accompanied the county press release. It states:

The ash and debris that remain on properties affected by wildfires on Maui pose a threat to human health and the environment. The ash and debris can contain harmful contaminants like asbestos, lead, and arsenic. If disturbed by wind, rain, or reentry activities, humans can be exposed to harmful chemicals. Harmful chemicals can also enter the local ecosystems, endangering wildlife, coral, and potentially entering the food chain.

EPA has reviewed proprietary data on Soiltac, the soil stabilizer selected for use on Maui, and confirms that it is non-toxic. The agency believes that applying a soil stabilizer is more protective of public health and the environment than leaving ash and debris as-is. Application of a soil stabilizer helps reduce inhalation risks and the spread of ash to water or surrounding properties.

EPA applied Soiltac in late September on burned properties in Kula after we completed the removal of the household hazardous materials. The soil stabilizer was used due to it being nontoxic, transparent when dry, safe for animals (EPA did not want to use a product that could entrap wildlife; it is only sticky for approximately one hour), and technical information was available for a prompt and thorough review. The liquid was applied only to ash and burned debris footprint, not to vegetation.

EPA applied two coats of the soil stabilizer, with about 20 minutes between the two coats.

Using the soil stabilizer in Kula demonstrated that this product can be applied effectively to burned properties, reducing the potential exposure to ash and debris. EPA has determined that using Soiltac is an effective short-term measure to stabilize the ash and debris to protect people and the environment until the Phase 2 removal can be conducted.


Why is a soil stabilizer being used on Maui?

Applying a stabilization product like Soiltac will prevent health effects from exposure to ash and soot from the wildfire and limit the spread of this material in the community further reducing human exposure. Because it binds the ash and soot it will also help 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).

EPA will apply soil stabilizers to the ash and debris footprints of buildings in Lahaina in coordination with Maui County and local officials. EPA will supervise the application of soil

stabilizers, ensuring all health and safety guidelines are followed to adequately protect residents and workers.

Prolonged exposure increases the risk of heart disease, stroke, lung cancer, chronic obstructive pulmonary disease, lower respiratory infections, and death.


Is Soiltac toxic?

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


Is Soiltac biodegradable?

EPA does not consider Soiltac to be biodegradable.

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 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 shell 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.


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 will be applied to all properties in Lahaina.


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 application process. 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.


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 based on feedback from the community, as well as the Maui Wildfire Response Phase 2 removal effort by USACE, as the ash and debris must be visible to Phase 2 personnel.


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.


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 Control oversaw the application of Soiltac in a removal action in Fresno, CA. 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 be effective for four to six months.


When will soil stabilizer be applied and by whom?

EPA managed field teams will begin applying soil stabilizer on once we have received approval for Lahaina.


When will soil stabilizer be removed?

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

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