The Hawaii Department of Health says a trace amount of toluene has for the first time been detected in water samples collected at the Upper Kula Treatment Plant on Maui.

The water from this plant is not covered by the county’s current “do not drink” advisory resulting from the Maui wildfires, which remains in place as water samples from the area undergo a third round of testing.

DOH says the Upper Kula water system, or Public Water System HI0000215, serves part of Maui’s Upcountry area.

Lab reports confirmed the detections of toluene on Aug. 14 and 16, according to DOH, which was notified of the results by the Maui Department of Water Supply on Aug. 28.

DOH then has 14 days to notify the public of the results.

Officials said the detected level for toluene at the Upper Kula Treatment Plant was well below the method reporting limit — or the smallest concentration detected in a sample that can be considered reliable — of 0.5 parts per billion.

It was also well below the federal and state maximum contaminant level of 1,000 parts per billion, officials said.

Federal and state standards are set to avoid health risks based on a lifetime of consuming water containing that level of contaminant.

Toluene is predominantly used as an industrial feedstock and a solvent, according to officials. It is also the main component of paint thinner, permanent markers, contact cement and certain types of glue — and it may be discharged from petroleum factories.

“This strongly suggests its presence was an artifact of the wildfire impacting the surface water source for the Upper Kula Treatment Plant,” said DOH in a news release. “Further monitoring is planned by MDWS at the Upper Kula Treatment Plant. To date, the Upper Kula water system is, and continues to be, in compliance with federal and state toluene standards for drinking water.”