The Navy says it will install more monitoring wells around its massive Red Hill fuel storage facility to make sure that leaked fuel that has contaminated the groundwater isn’t migrating toward county drinking water supplies, an environmental threat that state and county officials say is a growing concern for them.

Mike Williamson, commanding officer of Naval Facilities Engineering Command Hawaii, outlined the commitment during a joint legislative committee hearing at the State Capitol on Friday, where Navy, state and county officials spent two hours briefing lawmakers about a recent 27,000 gallon fuel spill at the facility.

Williamson said that the Navy also plans to update its groundwater protection plan, look into cleaning up the fuel from this most recent spill, research better leak prevention and detection technology and establish a task force comprised of Navy, state and county officials to address concerns at the Red Hill facility.

“We are fully committed to protecting the environment and our vital fresh water resources,” Williamson told lawmakers. “We drink the water, too. I believe we have taken prudent measures to ensure that the water remains safe to drink.”

However, the head of Honolulu’s Board of Water Supply, which is responsible for maintaining the safety of the county’s drinking water supply, seemed less than reassured by the Navy’s commitments.

Ernest Lau, manager of the water supply board, told lawmakers that the Red Hill Underground Fuel Storage Facility, which contains 18 active underground tanks, each big enough to envelop the Aloha Tower, today poses a risk to Oahu’s drinking water supply and that the Navy needs to retrofit its aging tanks.

“The cost to the community and to the Board of Water Supply is going to far outweigh the cost of retrofitting these tanks,” Lau told lawmakers.

The Navy has been exempt from costly leak detection and prevention technology that gas stations have had to comply with for three decades. This could change, however, as the U.S. Environmental Protection Agency moves to close the exemption as early as the end of the year.

It remains to be seen what improvements the Navy will have to make to its World War II era facility. But the January leak at the facility — and subsequent media reports that the facility has leaked extensively over the years and contaminated groundwater — will likely add to the political pressure for the military to invest in costly new technologies.

Navy officials said Friday that they were looking into improved technologies, but expressed reservations about costs and the significant reduction in fuel capacity if they have to double-line their tanks.

Navy reports and correspondence filed with the health department show that there have been dozens of leaks at the facility over the years. While records are spotty, the Navy estimates that about 1.2 million gallons of fuel has leaked over the years. By the early 2000s, it was clear that 19 out of the 20 tanks have had leaks. Two of the tanks have subsequently been deactivated.

A series of monitoring wells drilled by the Navy in recent years indicate that the groundwater below and around the facility has been contaminated with hydrocarbons as high as 25 times what the state considers safe.

The contamination is believed to pose the greatest risk to a nearby Navy well that supplies drinking water to about 65,000 people at Joint Base Pearl Harbor-Hickam.

However, recent analysis indicates that the contamination may be heading toward county drinking water supplies, according to Gary Gill, deputy director for environmental health at the Hawaii Department of Health, who also testified at the hearing.

He said that while the prevailing thought has been that the contamination would migrate mauka to makai, toward the Navy well, there are indications that it could also be moving in other directions.

However, Lau told Civil Beat that the analysis of the threat to the county’s aquifer isn’t so recent. Rather, the Navy disclosed the risk in a 2010 report filed with the state health department, in which it recommended that two wells be drilled to monitor any contamination heading toward county wells.

Lau said that the wells were never drilled.

Lau and other top officials at the Board of Water Supply have criticized the Navy and state health department in recent weeks for not informing them about the history of spills and groundwater contamination, saying they would have increased water monitoring years ago if they had known.

Lau recently sent letters to the Navy and Linda Rosen, the new director of the state health department, urging them to communicate better with the water supply board and take more proactive steps to prevent drinking water contamination.

“A small release of several thousand gallons (of fuel) could produce a groundwater plume that impacts the Navy’s Red Hill Shaft water supply,” Lau wrote in a letter to Navy Rear Admiral Richard Williams. “The reports also warn of the mounting age of the facility increasing the chance that both the metal tank liners and the concrete foundation walls may fail altogether, making future releases more of a concern.”

The county’s Hawala Shaft and Moanalua drinking water wells supply Oahu with about 13 million to 14 million gallons of water a day, or 25 percent of Honolulu’s drinking water supply, said Lau.

Navy reports indicate that if the drinking water is contaminated, cleaning the water supply could take decades and be cost-prohibitive.

“We are very concerned. The drinking water aquifer is a precious, precious resource that we cannot afford to get contaminated by this facility,” Lau told Civil Beat after the hearing.

“I believe that there is a potential risk to the aquifer today from this facility. And I hope to continue the discussion and encourage the Navy to make a commitment to protect the resources by taking appropriate actions in retrofitting their facility if they want to continue to use it.”