The Navy said Friday that a spill of up to 1,500 gallons of toxic fire suppressant containing so-called “forever chemicals” at Red Hill on Dec. 7, 2019, did flow outside of the facility and contaminated the soil, requiring the soil to be excavated.

The Navy, which disclosed the spill this week to the U.S. Environmental Protection Agency, said that at the time of the release, it was not required to report the incident to regulatory agencies or internally within the U.S. Department of Defense.

The fire suppressant, called aqueous film-forming foam, had not yet been defined as a hazardous substance by the EPA, and DOD had not yet implemented reporting requirements, according to a Navy spokesperson.

The state Department of Health, which regulates the facility along with the EPA, did not respond to Honolulu Star-Advertiser questions Friday about the spill, including whether there were any reporting requirements at the time and when it was first notified of the release.

The Navy said the spill occurred near Red Hill’s underground pump house, an area near Makalapa Crater that is makai of Kamehameha Highway near Pearl Harbor. The pumping station, which is at the end of the Red Hill pipelines, is used to move fuel up to the underground tanks and helps dispense fuel to ships and to nearby Hickam Air Field, according to information from the EPA.

The Navy said that an AFFF tank within the facility had a maximum capacity of 1,500 gallons but that it didn’t know exactly how much of the concentrated formula was in the tank at the time of the spill. It conservatively estimated the size of the release to be about 1,500 gallons.

The AFFF spilled within a building and flowed outside to an adjacent area, and a military spill response team promptly responded, the Navy said.

The Navy said the release did not affect a drinking water source.

Regulations governing AFFF spills, which contain chemicals called PFAS, have become much stricter in recent years as concerns have mounted about the health and environmental risks posed by the chemicals. PFAS are a group of man-made chemicals that do not break down easily in the environment or the human body. They’ve been widely used over the years in industrial processes and can be found in such consumer products as stain-resistant carpeting, certain cookware and food packaging.

But AFFF, which is deployed by firefighters to extinguish flammable-liquid fires such as fuel fires, has been found to be the primary pathway for the chemicals to enter the environment, according to the U.S. Department of Energy.

The Navy is now required to report AFFF spills to DOH, which it did when approximately 1,300 gallons of AFFF spilled at Red Hill on Nov. 29, requiring a major cleanup operation overseen by regulators and follow-up testing of the soil.

Following that spill, the EPA required the Navy to provide it with extensive information about past AFFF spills at Red Hill. The Navy turned over that information by Wednesday’s deadline, but most of the report has not been released publicly. The EPA and Navy said the documents are being reviewed to see whether anything needs to be withheld for security reasons.

The documents are expected to provide more detailed information about the 2019 and 2022 AFFF spills, as well as another spill that occurred in September 2020.