There is a coordinated, interagency effort to implement environmental protection and monitoring following the August 2023 wildfires. Agencies and organizations at the Federal, State and Local levels are all taking steps to mitigate environmental impacts from dust, ash, debris, and other effects of the wildfires. 

Mitigation and monitoring efforts seek to protect the people, land, shoreline, and water of all areas impacted by the devastating wildfires in Maui County.

The Hawaii Department of Health (DOH) is working closely with the U.S. Environmental Protection Agency (EPA) to collect and analyze air quality monitoring data. The agencies have announced that results from preliminary air sampling and air monitoring conducted in Lahaina and Upcountry Maui are reassuring. The results do not show evidence of poor air quality or any hazardous levels of contaminants in the air at the time the samples were collected.

According to the DOH, typical air monitoring is indicative of the ambient air quality, and high winds or cleanup activities could cause dust and ash to become airborne. DOH and EPA continue to closely monitor air quality as re-entry, cleanup, and debris removal activities take place. 

To mitigate re-entry and cleanup impacts on air quality, the EPA is applying Soiltac, a soil stabilizer, to the ash and debris footprints of burned buildings and vehicles. According to the EPA, the application of this stabilizer minimizes the movement of ash, debris, and contaminants through the air, land, and water, helping to protect the impacted and surrounding environment.  

The U.S. Army Corps of Engineers (USACE) will be coordinating with federal, state and local partners to conduct the government-sponsored debris removal program. During debris removal work, USACE will coordinate environmental testing and use best management practices for removing debris to mitigate impacts to air quality. All debris removal will be required to adhere to these standards. This includes expediting the removal of ash and debris to minimize environmental impacts.

DOH continues to urge Maui residents to wear a high-quality mask, such as an N95 mask, and other personal protective equipment when in impacted areas. Precautions should also continue to be taken in nearby areas should the air quality change due to disturbed ash from an impacted area. 

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Air Quality Testing Information

According to the DOH and EPA, in addition to baseline air sampling conducted, EPA and DOH installed 13 real-time PM2.5 sensors in Lahaina and Upcountry Maui following the wildfires. The monitors scan for a very fine, dust-like material called “Particulate Matter” or PM 2.5, which is indicative of ash and dust.

Contaminants of concern, such as metals like lead or arsenic, stick to the pieces of ash and dust that register as particulate matter. Because of this, air monitoring for PM2.5 can be used as an indicator for contaminant monitoring. If PM2.5 measurements are not above typical baseline levels (remain in the green zone), then ash and dust from the impacted areas, with their associated contaminants, are not in the air in any measurable amount that would be considered harmful.

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Air Quality Resources

• DOH provides a Guide for Maui Wildfires Air Quality Particle Pollution
• Individuals can access air quality monitoring data in real-time using the EPA’s air monitoring website
• Information released by the DOH provides further details on testing methodology. 
• The EPA website provides Maui Wildfire-specific information, including further information on Soiltac. 

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‍Watersheds and Nearshore Waters

The DOH, State of Hawaii Department of Land and Natural Resources (DLNR), U.S. Geological Survey (USGS), County of Maui, the University of Hawaii (UH) and many conservation groups are working collaboratively to monitor impacts and protect watersheds, nearshore waters, and coastal ecosystems.

Many efforts serve to protect both watersheds and nearshore waters. For example, following the fires, the County of Maui’s Department of Public Works (DPW) immediately deployed Best Management Practices (BMPs) within the burned area to protect drainage systems and waterways. Filter socks and straw waddles have been placed around drain inlets and catch basins throughout the town. Turbidity curtains and check dams have also been installed downstream of burned structures where there is potential to direct runoff toward the ocean. DPW continues to develop and innovate BMPs related to the burn area.

The Army Corps of Engineers is also expediting the removal of ash and debris to limit exposure to near shore waters and watersheds.

The Hawaii Department of Transportation is implementing a stormwater capture system in Lahaina. For more information on this please see the information below.

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Department of Transportation - Ka 'Oihana Alakau

JOSH GREEN, M.D. GOVERNOR | KE KIAʻĀINA
ED SNIFFEN DIRECTOR | KA LUNA HOʻOKELE
For Immediate Release: Nov. 21, 2023

Emergency Stormwater Capture System to be installed in Lahaina

Capture system will help prevent disaster debris from flowing into the ocean

LAHAINA, Hawaiʻi – The Hawaiʻi Department of Transportation (HDOT), County of Maui, and the Federal Highway Administration (FHWA) is installing an emergency stormwater capture system in Lahaina to reduce the environmental impact from silt, ash, and other disaster debris potentially entering storm drainage systems.

The $40 million project, which includes design, construction management and continued management of the system through 2024, is funded through the FHWA Emergency Relief program. The area to be covered by the stormwater capture system includes the entire length of Front Street, Honoapiʻilani Highway between its southern connection with Front Street and Wahikuli Wayside Park, and stormwater inlets in Leialiʻi Hawaiian Home Land, Kapunakea, Mala, the Puʻunoa Beach area, Lahaina Town, Lunaville, and Waineʻe. A map showing the project area can be seen here.

Work to prepare the area for installation has begun. People may notice the Best Management Practices (BMPs) in the form of green “socks” or fences to filter sediment and pollutants being installed in the project area. Additional measures may include:

• Debris removal through street sweeping, vacuum trucks and road crews.
• Source control through the application of hydromulch in open grubbed areas that are historically prone to erosion during storm events. Only nontoxic and biodegradable materials that have previously been used on Maui will be used for the hydromulch.
• Inlet protection using sediment fabrics on inlets and catch basins to provide additional filtering of stormwater as it enters drainage structures.
• Capture and treatment by temporarily capturing and diverting stormwater for pollutant removal before discharging it back into the storm drainage system.

For more information on Maui stormwater management visit stormwatermaui.com and the Maui County Stormwater Management Program.

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Nearshore Waters

A number of groups are working together to monitor nearshore water quality and protect critical ecosystems and reefs.

DOH’s clean water branch continues to conduct coastal water surveillance and watershed-based environmental management to protect coastal and inland water resources.  DOH also provides constantly updated water quality monitoring information and advisories.

In September, DLNR, in collaboration with USGS, began collecting data through sampling instruments in the waters just off the coast of West Maui. The sophisticated sampling instruments mimic what a living creature would absorb in order to understand exposure to fire related impacts.  

In October, UH and the Pacific Whale Foundation installed water quality sensors in ocean waters around the Lahaina impact zone. UH has identified a wide range of partners and collaborators on their research and protection efforts, which include DLNR, the West Maui Watershed and Coastal Management program, the DOH, the UH Maui College water quality lab, Hui o Ka Wai Ola, the Pacific Whale Foundation, and members of the Lahaina community.

According to the University of Hawaii “the UH team is working collaboratively with the community and county, state and federal experts to identify the pollutants and assess their abundance and ultimately determine if they will alter the ecosystem and affect its resilience in the future. The team was awarded a rapid response grant from the National Science Foundation (NSF) to study the immediate impacts from the contaminants created by the fire.”

U.S. Environmental Protection Agency is also working to prevent ash tainted with contaminants from blowing or washing into the ocean. The application of soil stabilizer Soiltac not only protects air quality, but also mitigates runoff and water contamination. Additionally, the EPA has done extensive hazardous waste removal to ensure that high-risk hazards and contaminants are removed from the fire impacted areas.

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Nearshore Water Resources

University of Hawaii News : UH researchers investigate nearshorewater quality, reef health after Maui fires
Departmentof Land and Natural Resources (DLNR) News and Information
StateDepartment of Health, Clean Water Branch: Water Quality Advisory Information

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Watershed Protection

The County of Maui’s Department of Public Works has been implementing a range of projects within burned areas to protect drainage systems and waterways. Implementing best management practices around drain inlets and catch basins serves to protect watersheds and offer environmental protection.

The County and Maui Soil & Water Conservation districts have been working with the USDA’s Natural Resources Conservation Service (NRCS) Pacific Islands Area office to secure critically needed federal funding and technical assistance through its Emergency Watershed Protection (EWP) program.

The EWP program is designed to safeguard life and property from imminent hazards caused by natural disasters. The SWCDs of Olinda-Kula, West Maui and Central Maui have collectively applied to partner with NRCS as the EWP Program Sponsor.

Watershed protection and prevention of soil erosion efforts are being deployed to prevent infrastructure damage and flooding that can threaten structures and lands downstream of burned areas. Some possible upcoming EWP projects include appropriate revegetation efforts to stabilize soil and prevent erosion; controls to protect the young plants from feral deer; restoration of water systems; and removal of large quantities of debris from difficult terrain.

In addition to watershed protection efforts, water systems and drinking water sources continue to undergo extensive testing from the Maui County Department of Water Supply, DOH, and EPA. To learn more about drinking water advisories and monitoring efforts, visit https://www.mauirecovers.org/utilities.

Watershed Protection Resources

University of Hawaii at Manoa, Water Resources Research Center: Maui Post-Fire CommunityDrinking-Water Information Hub

Maui Soil & Water Conservation Districts: Website and Information

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Land and Soil Quality

The EPA and all partners involved in debris removal and management are coordinating efforts to protect land and soil quality. During debris removal, the EPA is applying Soiltac, a soil stabilizer, to the ash and debris footprints of burned buildings and vehicles. Application of the stabilizer will prevent ash (and the contaminants within) from spreading to soil and land outside of burned areas.

Ash testing has also been conducted by the DOH to monitor the possible contaminants present within fire impacted areas. Based on data gathered in October 2023, DOH found high levels of arsenic in wildfire ash in Kula, along with elevated levels of lead and cobalt. Samples in Kula were taken from homes built between the 1930s to the 2000s. Given the similar ages of homes, DOH anticipates similar findings in Lahaina.

The U.S. Army Corps of Engineers (USCAE) is also conducting extensive environmental testing before and after debris removal activities. Soil testing will be conducted to ensure the site is safe and clear of potentially leached toxins. Six inches of soil will be scraped from wildfire damaged sites and then soil quality will be tested. If testing shows the presence of any toxins, USCAE will perform further remediation until they can ensure the soil is clean and safe for rebuilding and habitation. Cultural monitors will be on site during all USCAE clean up and remediation efforts.

Extensive debris removal efforts serve to create clean and safe impact zones. To learn more about debris removal efforts, visit resources from the EPA, USCAE and County of Maui.

Land and Soil Quality Resources

DOH: Preliminary ash testing data
FEMA and Maui County: Fire Debris Removal and Environmental Testing Information
U.S. Army Corps of Engineers: Hawaii Wildfire Response Information
U.S. EPA: 2023 Maui Wildfires

Disclaimer: The information on this page provides well-informed, broad overviews of environmental protection efforts. Information may not be an exhaustive list of all protection measures taken by local, state, and federal partners. Information contained in this page is subject to updates and changes.

Soil & Ash

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 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.