The preliminary finding of high levels of diesel at a monitoring well at Tripler Army Medical Center is prompting new alarms from state and city officials.

State Deputy Health Director Gary Gill told members of the City Council Public Works and Sustainability Committee Wednesday that he was informed by the Navy last week about the new petroleum contaminant. The preliminary findings showed 790 and 660 micrograms per liter, which are above the Health Department’s "environmental action level" of 100 micrograms per liter.

The news comes on the heels of the Jan. 13 discovery that an underground storage tank at nearby Red Hill leaked up to 27,000 gallons of jet fuel. Health Department and Honolulu Board of Water Supply officials have said that to date, there have been no indication the fuel has contaminated the groundwater aquifer. The cause of the leak has not yet been determined.

If the Navy’s subsequent testing at Tripler confirms the preliminary findings, there would still not be any immediate evidence that the fuel traveled from the 20-tank Red Hill facility, Gill said.

Another likely source of the diesel is from Tripler itself, Gill said, noting that a landfill and gasoline stations were once on the grounds.

"Either one is not good news," Gill said, saying that the Tripler monitoring well is about half of the 1.3-mile distance between the fuel tank facility and the Board of Water Supply’s Moanalua wells.

If confirmed, "that’s of grave concern for two reasons," he said. "Either the Red Hill plume is going south … or there’s a whole different source of contamination that’s polluting that groundwater, which might be even worse."

Ernest Lau, Board of Water Supply manager, said the new finding only heightens his agency’s call for the Navy to ensure the island’s water resources are protected.

Lau told committee members that the Board of Water Supply’s five wells in the vicinity of the storage tanks continue to show no signs of contamination. Lau said the roughly 3,500-foot distance from the Tripler well to the city’s Moanalua wells is worrisome.

"This is the Moanalua aquifer from which we draw drinking water with very little treatment except chlorination," Lau said. Installing treatment features at the wells could cost an estimated $50 million and take five to seven years, he said.

Wells in the area supply water from Halawa to Hawaii Kai, about one-quarter of the Board of Water Supply system, Lau said.

Lau wants the Navy to install more monitoring wells, increase testing and sampling to define the extent of the fuel contamination of groundwater in the area, and, if necessary, remediate any contamination that may exist.

Navy officials did not attend Wednesday’s Council committee meeting and were not available for comment after business hours.

The committee, after its discussion with Gill and Lau, advanced Resolution 14-110, which calls on the Health Department to press the Navy to work expeditiously to mitigate any potential adverse effects from leaks or spills originating from the fuel storage facility. Built during World War II, the facility provides fuel for ships and aircraft at Joint Base Pearl Harbor-Hickam about 2.5 miles away.

The Navy has reported that there have been dozens of fuel releases in the past totaling 1.2 million gallons, which the state received no information on before 2010 and little information on since, Gill said.

"I look at the Red Hill facility as one, big, long 70-year spill," Gill said. "And when we find petroleum products in the subsurface rock and in the groundwater, we have to assume that this was a historic spill that may be decades old."

Gill said the Navy has been cooperative, including sharing evidence that groundwater in the area of the tanks flows northwest in the direction of the Board of Water Supply’s Halawa Shaft about 5,000 feet northwest. The Navy has also found trace elements of naphthalene in its own drinking water supply, although at levels too low to be a health concern.

His agency is working on a draft of a consent agreement outlining what actions it must undertake, Gill said. "We have every indication that they will be making the resources available that are necessary to do this remediation work," he said.

Councilman Breene Harimoto, who co-introduced the resolution, said he’s frustrated that there’s been little action five months after the danger to Oahu’s groundwater was first exposed. "We’re still waiting for paperwork to occur."

Gill said "there’s a lot in play beyond just their response to just this one spill," including the long-term future of the tank facility. "If they’re going to use those tanks, they need to bring them up to speed. That’s billions of dollars. There’s lots of work to be done on these 70-year-old tanks."