State lawmakers advanced a resolution this week urging environmental regulators to require the Navy to do more to safeguard its massive, underground fuel tanks near Pearl Harbor or relocate them entirely.

The 18 active tanks sit 100 feet above a major aquifer that supplies drinking water to Oahu. If that aquifer is polluted by a major failure at one of the Red Hill tanks or by a migrating plume of leaked oil, it could be cost-prohibitive if not impossible to clean up, state officials have said.

Regulators with the state Department of Health and U.S. Environmental Protection Agency have been working with the Navy to enforce a legal agreement to improve the tanks’ safety since January 2014, when 27,000 gallons of oil spilled from one of the tanks.

As part of the requirements for improving tank safety, the Navy has to assess six options, including building new tanks, constructing a tank within a tank and double-lining the tanks. The Navy informed regulators last year that it would recommend an option that its own report described as “minimal changes to the status quo.”

That option, which must be approved by regulators, would involve coating the lower domes of the tanks to prevent corrosion and coating tank nozzles. The Navy would also fund an upgrade to its leak detection system and consider applying an experimental epoxy coating to one of the tanks.

Senate Concurrent Resolution 35, introduced by Sen. Mike Gabbard (D, Kapolei- Makakilo), calls on the EPA and state Health Department to reject that option. The resolution, which requires further House and Senate approvals, also recommends relocating the tanks if secondary containment isn’t feasible.

The resolution doesn’t carry the force of law, but, if passed, adds to the political pressure on the Navy and regulators. The Honolulu City Council recently approved a similar resolution.

The Navy opposed the resolution and testified that selecting a tank upgrade option needs to be carried out in accordance with the legal agreement and evaluation requirements.

“It’s a very complex decision-making matrix,” said Marc Delao, a captain at Naval Facilities Engineering Command Hawaii. “And the aquifer, protecting the aquifer, making sure that we don’t have leaks, that is extremely important, and so we are taking that very seriously.”

Lawmakers on Wednesday appeared visibly frustrated at the slow pace of work during the joint Senate hearing before the Agriculture and Environment Committee and Public Safety, Intergovernmental and Military Affairs Committee.

“I don’t know what kind of rocket science we have to wait for to realize that double walling at minimum is a course of action that the Navy should take,” said Sen. Glenn Wakai (D, Kalihi-Salt Lake-Aliamanu).

Ernie Lau, manager and chief engineer of the Honolulu Board of Water Supply, urged senators to pass the resolution. He stressed that the Red Hill tanks carried substantial risk to the island’s drinking water, explaining that the amount of fuel stored in the underground tanks is enough to cover the football field at Aloha Stadium and rise to the height of 500 feet.

“What do we leave for our next generation?” said Lau, who has argued for double- lining the tanks or moving them.

DOH Director Bruce Anderson said he believed the Navy was doing a good job ensuring that the tanks are being inspected and repaired. But in the long term, he said, the tanks need to be relocated.

In the end, said Sen. Laura Thielen (D, Hawaii Kai- Waimanalo-Kailua), the final decision on the Red Hill tanks doesn’t appear to be in the hands of local officials. If the Navy, EPA and DOH can’t agree on a tank upgrade option or whether to move the tanks, that decision will fall to a top EPA official, she said.

Thielen said the state, against her recommendation, had given up its veto authority over such decisions to the federal government when it signed the legal agreement.