About 1,100 gallons of toxic fire suppressant was spilled Tuesday at the Navy’s Red Hill fuel facility, an incident that state Department of Health officials described as “egregious.”

The aqueous film-­forming foam is used to suppress fires caused by flammable liquids such as fuel and contain PFAS, so-called “forever chemicals” that are slow to degrade in the environment. PFAS can lead to a higher risk of kidney and testicular cancer, and increased risk of high blood pressure in pregnant women, among other health problems, according to the Agency for Toxic Substances and Disease Registry.

The Navy said the spill occurred at about 1 p.m. and that federal firefighters responded immediately and contained the release, which occurred at Adit 6, a passageway on the mauka end of the Red Hill facility.

DOH, which has regulatory authority over Red Hill, said it wasn’t notified until two hours later, at around 3 p.m., and that when a DOH official arrived at the scene, the spill had not yet been contained.

Asked why DOH wasn’t immediately notified, Rear Adm. Stephen Barnett, commander of Navy Region Hawaii, said in a media call Tuesday night that the immediate focus was on assessing the situation and making sure workers were safe.

“The first thing we wanted to do was to get up there and assess the site and the extent of the release. That was the first thing that we had to actually do when we got up there,” he said. “We also had to make sure that we had our folks safely evacuated.”

Barnett said that the DOH official on-site was “happy with where we were heading and what we were doing.”

“But make no mistake about it, we take these reports of leaks very seriously, and this is a very serious incident and we are going to investigate the incident and we are going to make sure it doesn’t happen again,” he said.

Barnett said that the cause of the leak remains under investigation but that the AFFF appears to have leaked from a pipeline. He said that a now-empty tank connected to the pipeline had contained 1,100 gallons of AFFF.

Barnett said that the leak appears to have begun at around 1 p.m., but he didn’t know when it was contained.

Navy Rear Adm. John Wade, commander of the Joint Task Force-Red Hill, said engineers and contractors from Naval Facilities Engineering Systems Command were doing maintenance on the system Tuesday.

Navy and DOH officials said efforts are underway to recover the AFFF and that no surface water was contaminated.

“This is egregious,” Kathleen Ho, DOH’s deputy director of environmental health, said in the news release. “AFFF contains PFAS forever chemicals — groundwater contamination could be devastating to our aquifer. While details are limited at this time, the Joint Task Force and Navy need to be transparent about how this happened. 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.”

DOH officials said the Navy uses AFFF C6 at Red Hill and that the foam contains per- and polyfluoroalkyl substances (PFAS).

Hawaii Sierra Club Director Wayne Tanaka said the spill at the Navy’s facility raises serious concerns that the chemicals could migrate into the groundwater, in addition to the soil, posing an environmental and health hazard for generations to come.

“The fact that they have chosen to use AFFF containing PFAS just 100 feet above our drinking water aquifer is insane,” said Tanaka.

The release is the latest environmental blunder by the Navy, which was ordered to shut down Red Hill after a fuel release from the facility in 2021 contaminated the aquifer and the Navy’s drinking water system, which serves about 93,000 people, primarily military families around Joint Base Pearl Harbor-Hickam.

The Navy said its initial assessment is that the AFFF spill is unlikely to affect the drinking water or aquifer, based on the size of the release and its distance from an active water well. The Navy said the nearest well is the Red Hill shaft, which is about a mile away and has been shut down since it was contaminated by 2021’s fuel spill.

The Navy said the AFFF spill is not related to the defueling effort, which is part of the permanent shutdown of the facility. In early November the military finished draining about 1 million gallons of fuel from three pipelines that connect the underground tanks to Pearl Harbor. The major defueling of the facility is not expected to begin until early 2024, when the Navy plans to drain 104 million gallons from 14 tanks.

The lengthy timeline is based in large part on extensive repairs that need to be completed on the Red Hill pipeline system. An independent assessment of the facility released in May found that major repairs were needed in order for the tanks to be drained safely and to prevent a catastrophic release that could further pollute the groundwater, cause a major fire or potentially injure or kill workers.