The Hawaiʻi Department of Health (DOH) announced that preliminary, unvalidated data from ash sampling it received late Friday night shows very high levels of arsenic in wildfire ash collected in Kula.

The testing also indicated elevated levels of lead and cobalt.

Parameter	Unit	Lab Report #1	Lab Report #2	Lab Report #3	Mean Lab Reports	Soil Environmental Action Level
Arsenic	mg/kg	3,240	3,260	3,080	3,193	23
Cobalt	mg/kg	86	81	89	85	4.7
Lead	mg/kg	640	769	655	688	200

The ash samples were collected on September 21 from eight burned homes in Kula, which had been constructed from the 1930s to the 2000s. Because homes in the impacted area of Lāhainā were constructed during the same time period, DOH expects that the ash in Lāhainā will have a similar contaminant profile. With EPA phase 1 hazard removal nearing completion, DOH will conduct testing of Lāhainā ash.

Based on the new preliminary data, the primary contaminant of concern is arsenic, a heavy metal that adheres to wildfire dust and ash.  This finding reinforces the need to diligently follow recommendations to reduce potential exposure.

Click here to view the preliminary, unvalidated ash sampling data.

DOH is taking the following actions in Lāhainā and Kula based on this preliminary data to protect public health:

• In Lāhainā, DOH requested that the County of Maui and U.S. Environmental Protection Agency (EPA) prioritize the application of Soiltac, a dust control agent and soil stabilizer, on impacted zones closest to inhabited areas. As arsenic is a metal that adheres to ash, preventing ash and dust from becoming airborne will greatly decrease the risk of exposure to arsenic and other contaminants. The EPA completed Soiltac application in Kula and areas near Lāhainā schools.
• DOH recommends that the County of Maui install higher dust screens around the impacted areas and use water misters in Lāhainā to protect those residing next to the impact area to further control dust and ash from becoming airborne until Soiltac can be applied.
• DOH strongly recommends that the County of Maui cease the use of sifters in areas next to inhabited areas during Lāhainā re-entry visits, as the sifters cause ash to become airborne.
• DOH will conduct ash characterization testing in Lāhainā in coordination with EPA. DOH plans to collect hundreds of ash samples from impacted areas in Lāhainā to create a representative sample but can only do so after household hazardous materials are cleared from properties.
• DOH will also conduct additional air sampling in Lāhainā and Kula for heavy metals, including arsenic.  If ash or dust are not in the air at the time of sampling, it is unlikely that contaminants would be found in any measurable amount that would be considered harmful.
• DOH continues to install additional PM2.5 continuous air monitors. PM 2.5 is particulate matter that is 0.0025 millimeters and smaller in size (about 30 times smaller than a human hair) that can be a component of ash, dust, smoke, and air pollution.

All Lāhainā and Kula residents can monitor real-time air quality at fire.airnow.gov or by downloading the AirNow mobile app. Additional apps such as Local Haze, IQAir, and Paku use the same data sources and allow for real-time alerts.

DOH continues to analyze the results to assess any potential risks from other contaminants such as polycyclic aromatic hydrocarbons (PAHs), Dioxins, and others.