HONOLULU (AP) — The U.S. government on Friday dropped its appeals of a Hawaii order requiring it to remove fuel from a massive military fuel storage facility that leaked petroleum into the Navy’s water system at Pearl Harbor last year.

Attorneys for the U.S. Department of Defense notified the state and federal courts of its decision. The move comes more than a month after Defense Secretary Lloyd Austin said the military would permanently shut down the tanks and drain all of their fuel.

The Hawaii Department of Health, which issued the order, said the decision regarding the Red Hill Bulk Fuel Storage Facility was a “step forward.”

“While today’s announcement is good news, the work continues,” the department said in a statement. It said it would “continue to act expeditiously and proactively to oversee the safe defueling and decommissioning of Red Hill and restoration of the aquifer.”

David Henkin, an attorney for Earthjustice which is representing the Sierra Club of Hawaii as an interested party in the case said his clients would remain vigilant to make sure the tanks are promptly defueled.

“It’s a wonderful Earth Day gift to the people of Hawaii and in particular to all the residents of Oahu who depend on safe, clean drinking water when they turn on their tap,” Henkin said.

The Navy and the Hawaii Department of Health did not immediately respond to messages seeking comment.

Henkin said even if Austin were to change his mind and try to keep the tanks open, the military will now face “an enforceable, unimpeachable, unchallengeable order from the Department of Health that they need to follow.”

The order from the Hawaii Department of Health requires the military to remove fuel from the tanks 30 days after it’s safe to do so. The military will have to stick to this deadline now that it’s dropping the appeal, Henkin said.

The military, with oversight from the state health department and the U.S. Environmental Protection Agency, is currently developing plans to safely remove the fuel. It’s uncertain how long this will take.

Sen. Brian Schatz, a Democrat from Hawaii, said in a statement that the dropping of the lawsuit “paves the way for us to shut down Red Hill this year.”

The legal challenge made it hard for the state to work cooperatively with the Defense Department, Schatz said. He said he pushed hard for the military to make this decision.

Petroleum leaked from the Red Hill tanks into a Navy drinking water well late last year, sickening 6,000 people mostly living in military housing. Medical teams treated people complaining of nausea, headaches, rashes and other symptoms. The military put about 4,000 families in hotels for several months while it cleaned its water pipes.

The tanks also pose a threat to water consumed by 400,000 on Oahu. That’s because they sit 100 feet (30 meters) above an aquifer that serves the Honolulu Board of Water Supply, the city’s water utility, in addition to the Navy’s water system.

The city utility has suspended use of three of its wells until it can be sure petroleum won’t migrate through the aquifer from the area by the Navy’s well to its own wells.

The water utility and local leaders are also worried another spill could poison the city’s water system.

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