Results from testing ash samples in Lahaina show concerning high levels of toxic chemicals.
The state Department of Health on Sunday released laboratory results showing ash from homes in Lahaina contain elevated levels of toxics including arsenic, lead, antimony, cobalt and copper.
Samples were collected Nov. 7-8 from 100 properties in Lahaina, which were constructed anywhere from the 1900s to the 2000s.
Health officials continue to warn that the wildfire ash and dust on Maui are toxic and should be avoided.
“These data validate that the Lahaina ash contains toxic substances,” said state Health Director Dr. Kenneth Fink in a news release. “While the concentrations of these substances are lower than the Kula ash results, they are still elevated and it continues to be extremely important to take precautions. The risk remains greatest from ash ingestion. Inhaling disturbed ash and dust is also a potential route of exposure.”
Health officials continue to urge people to minimize their exposure by avoiding disruption of ash, and for those visiting affected areas to wear a well-fitting N95 mask and proper personal protective equipment.
DOH has been closely monitoring air quality in Lahaina and sampling air quality in Kula as the U.S. Army Corps of Engineers conducts the second phase of debris removal. Real-time results are available online at fire.airnow.gov.
The data from Tetra Tech Inc., officials said, validates that arsenic, which adheres to wildfire dust and ash, is the primary contaminant of concern.
“This finding reinforces the need to diligently follow to reduce potential exposure,” said DOH in a news release.
Arsenic is a heavy metal found in volcanic soils due to its use as an herbicide in the early 1900s, but it is also found in wood treated for termites and building materials made of Canec, or sugar cane.
DOH found levels of arsenic taken from Lahaina ash samples at a mean of 280 milligrams per kilogram after averaging results from three lab reports, 12 times more than the acceptable level of 23.
In comparison, the mean level of arsenic from Kula ash samples was reported at above 3,100 milligrams per kilogram.
But levels of lead from Lahaina samples were also concerning, at 410, double the acceptable level of 200. And levels of copper were more than double acceptable levels as well.
More than 50 real-time air monitors have been installed in Lahaina and Upcountry Maui, according to DOH, to measure PM (particulate matter) 2.5, which is matter that is 0.0025 millimeters or smaller — or about 30 times smaller than the width of a human hair.
Air monitoring of these particles can be used as an indicator for contaminants because metals like lead or arsenic stick to the pieces of ash and dust that register as PM 2.5.
During a week in November, data from air sampling in Kula, Maui, showed good air quality overall.
Health officials warn, however, that air monitoring and sampling only offer information on the ambient air quality at the time samples are collected, and that cleanup activities can cause ash and dust to become airborne.