Fuel leaks at the Navy’s Red Hill storage facility pose a grave hazard to Oahu’s environment and water supply. And revelations about the dimensions of this disaster keep coming, further complicating an already complex mandate to defuel the massive tanks.

This week, U.S. Reps. Kai Kahele and Ed Case, and Ernie Lau, chief engineer of the Honolulu Board of Water Supply, appeared at a town hall in Moanalua to deliver the latest bad news: Based on a Navy contractor’s report, it’s projected to take at least two years and cost more than $100 million to repair threatening weaknesses throughout the fueling pipeline system, just to get to the point that defueling of the tanks can begin. That’s stunning — about the cost of repairs, but even more so, in the lengthy period of time estimated.

Meanwhile, Oahu citizens live with a “ticking time bomb,” as a state Department of Health hearings officer put it, sitting above the aquifer, a primary source of the island’s drinking water.

Strict oversight of this defueling project is needed to ensure that it goes forward safely, but with all possible speed. It’s crucial that Hawaii’s governor and Department of Health participate fully, and press the Navy for information on how its defueling plan could be made more efficient.

The issue is magnified by a public crisis of confidence in the Navy — created by the Navy’s ongoing failure to adequately inspect and repair its 80-year-old system before this disaster developed, false reassurances of safety, and repeated efforts to stonewall Hawaii authorities who called for action.

Only in March did the Navy abandon its pushback against a state emergency order that it drain the underground tanks and address safety flaws at the facility, when Defense Secretary Lloyd Austin ordered that Red Hill be defueled and permanently closed.

Having reached a point at which it’s difficult to take Navy assurances at face value, there are concerns about the contractor’s report: The Navy did not consult with Hawaii’s DOH before unilaterally commissioning the evaluation of the tank system’s integrity, raising questions about whether the report serves Navy interests in delaying action.

Each day the Red Hill facility sits loaded with jet fuel, the aquifer supplying essential water to Oahu remains at risk.

“We are dealing with a nightmare here,” said Lau, between the prospect of a leak developing in the tanks while repairs occur, and the risk of a pipeline rupture while defueling.

The hazards aren’t conjecture.

Last November, 14,000 gallons of fuel and water leaked from a drain line at Red Hill. It contaminated the water system serving military families and civilians in housing there, schools and businesses, sickened thousands and resulted in a months-long water shutoff for about 93,000 people.

It’s now known that there have been as many as 76 fuel spills at the aging Navy facility since the early 1940s, pouring close to 200,000 gallons of petroleum into the ground. David Norfleet, an engineering expert consulted by the Honolulu Board of Water Supply, has testified that more leaks or spills are inevitable without remedial action.

A lawsuit in federal court filed by community group Wai Ola Alliance is a welcome development, in that it may provide additional court oversight of the Navy. In addition to its call to shut down the tanks promptly, the group is suing for fines against the Navy for past environmental violations.

The DOH has ordered the Navy to provide a defueling plan and schedule by next Thursday, followed by a plan by Nov. 1 for permanent closure. These plans must also be made public, so that the Navy can be monitored.

As Hawaii prepares to elect a new governor, it’s of primary importance that there be no loss of urgency. A new governor and new administration must be prepared to ensure a smooth transition that does not allow for any let-up in pressure for a prompt Red Hill facility cleanup and closure.