Approximately 14,000 gallons of fuel and water spilled from a drain line at the Navy’s Red Hill Underground Fuel Facility over the weekend, according to the Navy. The rate of release had slowed considerably as of Sunday evening and there were no signs that any of the fuel had seeped into the environment, according to a Navy press release.

The cause of the release, which occurred in a drain line that is part of the facility’s fire suppression system, is under investigation.

Shortly after 5 p.m. on Saturday, Navy personnel believed the release was a water leak, according to the Navy. But overnight, fuel was detected within the mixture and increased into Sunday morning. The Navy says that the fuel was contained in the lower tunnel and has been transferred to an above ground storage tank.

“There are no signs or indication of any releases to the environment, and the drinking water remains safe to drink,” according to the Navy press release.

The spill occurred about one-quarter of a mile downhill of about 20 underground fuel tanks, each capable of holding 12.5 million gallons of fuel. The tanks sit just 100 feet above an aquifer that serves as a major source of drinking water for Oahu.

The Navy says it notified the state Department of Health, which regulates the facility, on Saturday night.

The spill is the latest in a series of leaks at Red Hill that have alarmed Hawaii’s congressional delegation, state lawmakers and environmentalists in recent years.

In 2014, the Navy reported that 27,000 gallons of jet fuel had leaked from one of its Red Hill fuel tanks. Subsequent reporting by the media found that, based on the Navy’s own documents, there had been dozens of leaks at the aging World War II-era facility in past decades.

The U.S. Environmental Protection Agency and DOH significantly increased oversight of the facility following the 2014 spill, and environmental groups have stepped up pressure on the Navy to relocate the facility to protect the state’s drinking water.

Earlier this year, the Navy reported that 1,618 gallons of jet fuel leaked from the Red Hill facility in May.

Navy officials also disclosed that from March 2020 to May 2021, 7,100 gallons of fuel was recovered from the water and soil of Pear Harbor, which likely included a mixture of new and older sources. The Navy says that the 7,100 gallon release was not related to its Red Hill facility, but DOH documents have suggested otherwise.

The Navy has been criticized for obfuscating for the problems it has been having at Red Hill. Earlier this month, Hawaii’s congressional delegation called on the U.S. Department of Defense’s Inspector General to launch an independent investigation into whether the Navy “covered up evidence or intentionally delayed” notifying state regulators about the leak of fuel into Pearl Harbor.

Earlier this month, it was also revealed in government documents that a Navy whistleblower had told environmental regulators that the Navy has withheld information about holes and corrosion in its Red Hill tanks that have been identified during inspections in past decades, as well as the location of a pipeline, as it seeks a state permit to continue operating the fueling facility near Pearl Harbor.

Based on the claims of the unnamed naval officer, the DOH’s Health’s Environmental Health Administration requested that the DOH director expand a contested case hearing over the Navy’s permit application to look into the claims.