The military task force draining the fuel from the Navy’s underground Red Hill fuel facility announced Friday that it had wrapped up the last of its major milestones for the year, completing “gravity defueling” operations.

It will begin the last phase of the defueling in January.

Since October, Joint Task Force Red Hill has drained approximately 104,642,160 gallons from the massive underground fuel farm, which sits just 100 feet above a critical aquifer most of Honolulu relies on for drinking water. On Friday it said it “unpacked” the last fuel from the pipelines that connect the fuel tanks to facilities in Joint Pearl Harbor-Hickam.

The facility was built inside a mountain to allow the tanks to use gravity to feed the pipelines connecting Red Hill to Joint Base Pearl Harbor-­Hickam, saving the energy that might otherwise be required to pump fuel through the pipes. According to a news release, “JTF- RH now shifts focus to prepare for the safe removal of the majority of residual fuel, fuel in the pipelines that can’t be drained by gravity, approximately 60,000 gallons. This will begin mid-January, pending regulatory approval.”

The remaining fuel is expected to be mostly removed by the end of January, putting the defueling six months ahead of the deadline the task force had initially set for itself. When JTF-RH was first stood up in September 2022 under Vice Adm. John Wade, he said he hoped to complete the task by summer 2024 — though he said he would look for any available way to expedite the process.

The World War II-era facility and the pipelines had fallen into a state of deep disrepair and required extensive fixes and upgrades to ensure that the fuel inside the tanks could be safely removed without further risks to the aquifer.

Local officials and community leaders had long warned that the facility posed a threat to Oahu’s water supply, but Navy officials for years insisted the facility was well maintained, safe and critical to national security.

In November 2021 fuel from the facility tainted the Navy’s Oahu water system, which serves 93,000 people including service members, military families and local civilians. After initially resisting a state emergency order to drain the tanks, the Pentagon announced in March 2022 that it would permanently shutdown the facility.

After nearly a year of repairs, JTF-RH began defueling in October, and chartered commercial tankers have ferried fuel to West Oahu facilities run by Island Energy Services at Campbell Industrial Park, to a fuel storage point in San Diego, a fuel storage point in the Philippines at Subic Bay and another fuel storage point in Singapore. After years of insisting that Red Hill was critical to national security, Pentagon officials now say this new “distributed” model provides more flexibility and more “resilient” supply lines.

The defueling has been largely incident-free. During a public Fuel Tank Advisory Committee meeting in November, Wade said that in two incidents in October, about three gallons leaked along the pipeline but was quickly cleaned up “on the spot.”

Honolulu Board of Water Supply Manager and Chief Engineer Ernie Lau, who has been a vocal critic of the Navy’s handling of Red Hill, said he’s “actually quite pleased” with the way JTF-RH has handled its mission.

“The key has been that they have been really focused on doing this as quickly as possible and doing it safely,” said Lau. “So I do appreciate the effort.”

While the defueling is ahead of schedule, the cleanup and ultimate shutdown of the Red Hill facility — which will be overseen by a new Navy task force — is expected to take much longer. In November a state working group called on the federal government to pay for the cleanup of contamination around Red Hill in a report that estimated that as many as 2 million gallons may have leaked from the facility over 80 years.

“I would hope that the next group that takes it over will also have the same attention and focus to do it safely and quickly,” said Lau. “But the job won’t be done till the last drop of fuel or sludge is out of that facility.”