Safety stakeholder representatives and first responders conduct a safety walk-through at the Red Hill Bulk Fuel Storage Facility in Halawa, Hawaii, Oct. 12, 2022. (Matthew Mackintosh/U.S. Army)

FORT SHAFTER, Hawaii — Federal firefighters responded Tuesday afternoon to a leak of hundreds of gallons of fire suppressant foam at the Red Hill Bulk Fuel Storage Facility on the outskirts of Honolulu.

The leak was quickly contained, and emergency personnel were expected to work through the night to clean up the affected area, Rear Adm. John Wade, commander of Joint Task Force-Red Hill, told reporters during a conference call Tuesday evening.

The task force is charged with the removal of roughly 100 million gallons of fuel from the World War II-era underground storage facility.

Defense Secretary Lloyd Austin in March ordered the site permanently closed after a jet fuel leak contaminated the Navy's drinking water supply used by thousands of people living on and nearby Joint Base Pearl Harbor-Hickam.

About 1,100 gallons of Aqueous Film Forming Foam, or AFFF, was released from a tank near the top of the facility, Wade said. The cause of the leak is under investigation, he added.

AFFF is considered a hazardous material because it contains PFAS, or perfluoroalkyl and polyfluoroalkyl, a class of chemicals widely used in manufacturing processes since the 1950s.

The Environmental Protection Agency refers to the PFAS components as “forever chemicals” because they persist in the environment. PFAS exposure may lead to a variety of health effects, including an increased risk of cancer, according to the EPA.

Kathleen Ho, deputy director of environmental health for the Hawaii Department of Health, described the leak as "egregious" in a Tuesday news release.

"AFFF contains PFAS forever chemicals — groundwater contamination could be devastating to our aquifer," she said.

"While details are limited at this time, the Joint Task Force and Navy need to be transparent about how this happened," Ho said. "Regulators will hold the Department of Defense accountable and will press the operator to take any and all appropriate corrective action throughout the defueling and decommissioning process.”

The nearest Navy well is a mile from the site of the fire suppressant leak, and that well has been shut down since becoming contaminated in November 2021, Wade said.

The leak was discovered by workers conducting routine maintenance in the facility, Wade said. The leak and its discovery had nothing to do with the ongoing work of emptying the tanks, he said.

Workers have been placing absorbent mats on the affected area, as well as digging up and removing dirt and concrete to prevent the AFFF from spreading, Rear Adm. Stephen Barnett, commander of Navy Region Hawaii, told reporters during the conference call.

"There's a lot of people up there doing a lot of hard work right now," he said.

The Navy expects to have the fuel removed by summer 2024 and the facility shuttered by 2027.