Testing by the Honolulu Board of Water Supply earlier this summer indicated that a plume of contaminants often associated with petroleum fuel recently passed through a pair of drinking wells in Aiea near the Navy’s underground Red Hill fuel storage facility.

The wells are among those the BWS shut down and sealed off as a precaution after jet fuel from Red Hill contaminated the Navy’s Oahu water system, which serves 93,000 people, in November 2021. The facility sits just 100 feet above a critical aquifer most of Oahu relies on for drinking water.

After the November spill, residents on the Navy water­line reported a wide range of ailments. After months of resisting calls to remove the fuel and shut down the facility, the Pentagon relented. The tanks were finally mostly drained of fuel in March, and a Navy task force is working to permanently close the facility.

The recent positive tests for polycyclic aromatic hydrocarbons, or PAHs, came from tests the BWS conducted in May and June. According to a letter sent July 8 to the EPA by BWS Manager Ernie Lau, the board believes “the contamination may be related to the November 2021 petroleum release into Red Hill Shaft and/or past fuel releases from the Red Hill Bulk Fuel Storage Facility.”

The wells are about 2 miles west of Red Hill. The PAH concentrations reported were relatively low, but some exceeded the state Department of Health’s action levels.

“The results also indicated that contaminants can move in the aquifer with the groundwater flow under static pumping conditions and can appear without warning in unpredictable amounts,” Lau wrote. “This unpredictability makes the sizing and design of any contaminant removal treatment system technically challenging and potentially cost prohibitive.”

In the letter Lau asked the EPA to require the Navy to expedite a report on the extent of impact to the aquifer.

In a release of docu­­‑ ments to the Honolulu Star-Advertiser, the BWS said, “The detection of PAHs at the BWS Aiea Wells affirms the need to understand the impact of past fuel releases on the groundwater aquifer underlying the Red Hill facility. It also reaffirms the urgent need to complete studies to characterize the nature and extent of the fuel contamination in the aquifer, develop a numerical groundwater flow model and understand the fate and transport of the contaminants in the aquifer.”

In A letter dated Aug. 9, the EPA responded to the BWS, telling Lau, “We understand the BWS believes these detections may be related to the November 2021 fuel spill from the Red Hill Facility. To better understand and further investigate these detections, we are interested in receiving additional background and data from BWS about these detections.”

The response letter said EPA and DOH wanted, among other things, information on the methodology used. They also asked the BWS whether it considered the possibility that PAHs came from different sources than Red Hill, including the closer old Aiea Sugar Mill, runoff from roads and parking or construction by the BWS itself.

Navy Closure Task Force-Red Hill for its part said in a statement that based on the information provided by BWS, the Navy “does not concur with their conclusions.” The Navy statement said that the service conducts extensive biweekly sampling of a network of more than 40 groundwater monitoring wells around Red Hill where “test results do not support similar conclusions.”

Ever since a major fuel spill at Red Hill in 2014, the BWS and many community members and officials warned that Red Hill posed a potentially significant threat to Oahu’s water supply. The Navy for years insisted the facility was safe and vital to national security.

But after the November 2021 spill, military officials admitted the World War II-era facility had been poorly maintained and required extensive repairs to even safely remove the fuel. In the immediate aftermath the BWS shut down several of its nearby wells indefinitely. At the time Oahu was already reeling from drought, and the shutoff resulted in higher costs for water. The BWS argued that it it was not confident in the safety of those wells due to their proximity to Red Hill.

In his letter, Lau said that the recent results appear to justify that decision. Lau wrote that “it also reaffirms BWS’ repeated request to fully and expeditiously characterize and understand the impact of past releases on the groundwater aquifer underlying the Red Hill facility. The BWS will not allow our customers and water system to be exposed to fuel contamination appearing in our water without warning in amounts that could be highly variable and unpredictable.”