Navy officials worked to reassure members of a task force and the public Thursday that they are taking every precaution to ensure that 18 massive underground fuel tanks at Red Hill near Pearl Harbor won’t contaminate Oahu’s drinking water supply. In doing so, they stressed that the only leak at the facility since 1988, when underground fuel storage tank regulations were implemented, was in 2014, when 27,000 gallons of fuel was released from one of its tanks.

“The fuel released, now almost five years ago, was the one and only release to the public since … 1988. The one and only release,” said Rear Adm. Brian Fort, commander, Navy Region Hawaii and Naval Surface Group Middle Pacific, during a public meeting at the state Capitol. “That was due to a contractor’s error and poor oversight. We acknowledged that after it happened. Not due to an old, rusty leaking tank. That’s an example of fact versus opinion.”

Fort stressed, as did other Navy officials throughout the meeting, that he was delivering “nothing but facts. Veritas. Not conjecture. Not hyperbole,” in what appeared to be a dig at recent criticism of its progress in upgrading its fuel tanks.

Officials with the Board of Water Supply and environmental watchdogs have been skeptical of the Navy’s contention that there haven’t been other leaks at the facility since 1988, when military officials were first required to report leaks to regulators and clean them up.

Navy reports indicate that there were likely dozens of historical leaks at the facility, which was built in the early 1940s, and a 2010 audit by the Naval Audit Service referenced site investigations that “have shown evidence of fuel releases which have resulted in contamination of the rock bed, soil, and groundwater surrounding the (Red Hill) tanks.” The audit, in part, raised concerns about the Navy’s ability to detect “slow, chronic fuel releases.”

Honolulu Board of Water Supply Manager and Chief Engineer Ernie Lau augmented concerns about the existence of more recent fuel leaks when toward the end of the meeting, he passed out copies of documents signed by the Navy in 2002 that reported leaks at its Red Hill tanks to regulators with the state Department of Health.

One “confirmed release notification form,” signed in April 2002, indicates that there was a leak at Tank 6 of JP-5 fuel that affected the groundwater and possibly the surface water. The “tank has been drained and taken out of service,” according to the document signed by John Salvo, who was a lieutenant commander in the Navy at the time.

Another “confirmed release” form, signed by Salvo in July 2002, indicates a site investigation had discovered additional leaks at the facility.

“We are submitting a single Confirmed Release Notification form for the entire Red Hill Tank Complex, even though previous notifications were made for suspected releases at tanks 6 and 16,” a Navy official wrote in a letter to the state Health Department that accompanied the July 2002 release form. “This is because any response or remedial actions from now on will likely be directed at the complex as a whole instead of at individual tanks.”

Asked to explain the documents, Mark Manfredi, the Navy’s regional program director for Red Hill, told the Honolulu Star-Advertiser the Navy had initially believed that there had been a leak at tank 6, drained it and took it offline. After an extensive inspection of the tank, he said, no holes were found. After repairs were made to the tank, such as fixing rust spots, he said that the tank was brought back into service about five years later. He said that since then additional testing has shown no leaks at the tank, which would indicate that the tank had also not leaked in the past.

He didn’t immediately have information about a leak at tank 16, as referenced in the release documents. But he said he believed all the tanks currently in service have passed leak detection tests. The tanks can each hold 12.5 million gallons of fuel. The tank testing, which began in 2008, involves filling a tank and letting it sit idle for about five to six days to see whether there is a loss of mass in the tank. He said the testing can detect leaks of more than half a gallon of fuel per hour.

Manfredi acknowledged that there were historical leaks at the tanks that dated before 1988, when reporting requirements were passed. “But we don’t know precisely what was released, from what tanks, when and in what quantities,” he said.

Keith Kawaoka, the state Health Department’s deputy director for environmental health, said he would need to review the documents provided by Lau to better assess whether there had been leaks at Red Hill in or around 2002. “We’ve had reports, anecdotally, a lot of them, of (Red Hill) tanks leaking in the past and hundreds of thousands of gallons leaking, but nothing verifiable,” he said.