The Navy’s Red Hill fuel facility near Pearl Harbor maintains a continuous supply of nearly 200 million gallons of petroleum for ships and jets in colossal underground tanks perched just 100 feet above Oahu’s drinking water aquifer.

Its presence here — now approaching eight decades — serves as an ever-looming threat that a potential catastrophic leak could forever taint our high-quality groundwater.

That threat is now compounded by corrosion tied to the facility’s age. Saluted as something of an engineering marvel, Red Hill’s buried tanks — each large enough to swallow a 20-story building — were briskly constructed during the World War II era. Ongoing leak-related worries spiked in 2014, when 27,000 gallons of fuel were released from one tank.

In that case, the seepage was caused by contractor error and poor Navy oversight — not crumbling structure. Regardless of cause, though, the leak rightly touched off community call for a long-term plan to significantly reduce the risk of future releases and underground contamination that could devastate the quality of water pumped for municipal taps.

Now, five years later, the Navy is nearing completion of structural studies and evaluation of upgrade options, required by an Administrative Order of Consent with site regulators. Since much of the analysis was conducted in military quiet, it comes as a welcome relief that the state Attorney General’s Office recently called for more transparency.

Last week, in response to that call, the Navy turned over raw data pertaining to tank corrosion testing to its Red Hill site regulators, the U.S. Environmental Protection Agency and the state Heath Department. The DOH is now conducting its own assessment of the data — also an encouraging sign as the agency had a history of going easy on oversight of Red Hill. Too easy.

Decades ago, to address public safety and environmental concerns, state legislation was enacted directing the DOH to put in place rules requiring upgrade or replacement of underground tanks connected to public services or private business. Until just last year, it effectively exempted Red Hill — the Navy’s largest such fuel depot in the Northern Hemisphere.

No more. Now, in tandem with the federal EPA, the state DOH should redouble its scrutiny of data and the Navy’s expected proposal. It appears probable that the pitch will be to seek Pentagon support for the cheapest and least-protective site improvement option under consideration.

For its part, the Navy exudes confidence that its 18 operational tanks will be “tight,” leak-free well into the future while serving as a strategic asset in the U.S. Indo-Pacific Command.

It points out that the Department of Defense is already investing hundreds of millions of dollars to modernize Red Hill. Further, a recent laboratory analysis of tank steel plate samples, called coupons, shows that thickness exceeds twice the industry minimum standard for above-ground tanks.

Still, it should be deeply concerning to Oahu residents that Honolulu’s Board of Water Supply (BWS) does not share the military’s sense of confidence.

The BWS, which manages municipal water resources and distribution, lacks confidence that “existing maintenance practices” at Red Hill can detect potential leak areas and repair them before they occur. For safety’s sake, then, it opposes the Navy’s expected proposal to continue use of the aging “single-wall” tanks.

Honolulu’s City Council weighed in for the first time on the matter last week, passing a resolution urging the site’s regulators to reject proposed single-wall upgrades. Instead, the Council — along with the BWS — supports installing a double-wall, or secondary containment option for each tank; or relocation away from the fresh-water aquifer.

Those options come with a much higher price tag. But, then again, the bottom line for Oahu is that the aquifer is the only one of its kind here. It is priceless, as it cannot be relocated or replaced.