LOW LEVELS OF PFAS DETECTED IN FORT SHAFTER WATER SYSTEM ON OʻAHU

HONOLULU - Low levels of PFAS (perfluoroalkyl and polyfluoroalkyl substances) have been detected for the first time in water samples collected at Fort Shafter Wells Chlorinator. It is part of the Fort Shafter water system (Public Water System HI0000341), owned by the U.S. Army Garrison (USAG) Hawai'i. Fort Shafter Wells Chlorinator serves the Fort Shafter area of the island of O'ahu.

Two PFAS were detected: perfluorohexane sulfonic acid (PFHxS) and perfluorohexanoic acid (PFHxA). The water system formally notified the Hawaiʻi Department of Health (DOH) of the initial detection of PFAS via email on Sept. 23, 2026.

The detections of perfluorohexane sulfonic acid (PFHxS) and perfluorohexanoic acid (PFHxA) were sporadic, with PFHxS concentrations ranging from non-detected to 2.28 nanogram per liter (ng/L) which is below the U.S. Environmental Protection Agency (EPA) maximum contaminant level (MCL) for PFHxS of 10 ng/L, MCLs are the highest levels of contaminants that are allowed in drinking water by the EPA. PFHxA concentrations ranging from non-detected to 2.03 ng/L. PFHxA does not have a federally regulated MCL. The current DOH Environmental Action Level (EAL) for PFHxA in groundwater is 1900 ng/L. Both detections are unlikely to pose a public health risk.

According to the EPA, PFAS, which have been used since the 1940s, are fluorinated organic chemicals that have been used extensively in consumer products such as carpets, clothing, fabrics for furniture, paper packaging for food and other materials (e.g., cookware) designed to be waterproof, stain-resistant, or nonstick. They are also a component of firefighting foam and have many industrial uses.

For more information on PFAS, please see https://www.epa.gov/pfas or https://health.hawaii.gov/pfas. Users may also contact USAG Hawai'i, Directorate of Public Works, Environmental Division via phone at 808-787-1966 for water system inquiries.

This news release is issued in accordance with Hawaii Revised Statutes (HRS) § 340E-24(b), which requires notification of previously detected contaminants in underground sources of drinking water or any public water supply.

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