Environmental Monitoring

Maui Wildfire Data: Beach Sand

Beach sand is a type of sediment composed of various materials, including decomposed rocks and organic materials. Ash from the Maui wildfires may have made its way into the sediment in ditches and streambeds and in sand along the shore. Some of the ash may have settled out of the air, though this is unlikely given the strong winds at the time of the fires. DOH and partners are sampling the beach sand out of an abundance of caution and in response to public concern regarding the safety of beach recreation.

DOH and partners test beach sand to evaluate if fire-related substances are present in the sand and to assess possible actions that may need to be taken to protect public health and safety. DOH monitoring has shown that fire-related substances are present at levels consistent with background levels and are not present in tested beach sand at levels that would be harmful to people.

Beach Sand Sampling

In accordance with community concerns regarding the safety of beach recreation after the wildfires, particularly for younger children, DOH selected beaches for sampling nearest the burn area. On May 15, 2024, DOH collected sand samples from three public beaches near Lahaina (Figure 1), including:

• Hanakao’o Park
• Puunoa (Baby) Beach
• Kahekili Beach

DOH selected two of the beaches, Hanakao’o Park and Puunoa (Baby) Beach, for sampling based on their heavy historic and recent recreational use. DOH chose Kahekili Beach as a reference site for data comparability. Because Kahekili Beach sand is not expected to show impacts from the wildfires, DOH can compare the unaffected sand from Kahekili to sand from the other two beaches to understand fire-related effects.

DOH collected beach sand samples on May 15, 2024, in accordance with DOH’s Technical Guidance Manual (TGM), which provides in-depth guidance on collecting samples that best represent people’s possible exposure. DOH collected the beach sand samples within a 150-yard area above the high tide mark at each site. The samples were collected at depths between 0 and 3 inches. Due to the recent occurrence of the fires, fire-related ash is expected to be on the surface of the sand, within the top 3 inches of beach sand. People digging and playing in the beach sand are highly unlikely to encounter ash at deeper depths.

Beach sand samples were collected by DOH in accordance with DOH protocols.
DOH EAL: Hawaii DOH Environmental Action Level for screening. An entry of “—” means the analyte does not have an EAL. 
The table shows valid sampling results from the sites, including duplicate and triplicate samples collected for quality assurance purposes.
ND: Non-detect
*Values were J flagged in the laboratory report, indicating that the result should be considered as an estimated rather than quantitative value.
¹Screening values represent soil EALs for unrestricted land use obtained from DOH’s TGM EAL Surfer (Tier 1 EALs) search function (found here: Environmental Hazard Evaluation and Environmental Action Levels – HEER Office (hawaii.gov)) from Spring 2024. Where applicable, the EAL Surfer reports natural background levels if higher than the toxicity-based action levels and may account for the bioavailability of the substance.