HONOLULU - A Navy analysis may underestimate the contamination potential of leaks from giant fuel tanks near Pearl Harbor, environmental regulators said.

The U.S. Environmental Protection Agency and the Hawaii Department of Health sent a letter to the Navy last month outlining their concerns about the Navy's work.

The Navy has 20 underground fuel storage tanks dating to World War II in the hills above Pearl Harbor. The tanks sit on an aquifer that supplies a quarter of the water consumed in urban Honolulu.

More than 27,000 gallons leaked from one of the tanks in 2014.

The Navy and regulatory agencies are working on a 20-year-plan to reduce the risk of leaks and fuel contamination from the tanks. The plan includes evaluating new tank designs and potentially storing the fuel someplace other than Red Hill.

The letter, posted on the EPA's website, said the Navy and its consultants appear to be prematurely drawing conclusions about a model predicting groundwater flow and the movement of contaminants. It said the Navy's approach may not lead to a "conservative evaluation."

They included another letter from a consultant saying the Navy's evaluation "seems to be skewed" toward concluding that millions of gallons of jet fuel could be released without damaging the groundwater.

The consultant said the Navy doesn't seem to be taking the risks posed by fuel leaks into account to the same degree.

Rear Adm. Brian Fort, commander of Navy Region Hawaii, said the Navy is committed to working with regulators to continue a thorough study of the underground water at Red Hill.

"We have not and will not rush to judgment or conclusions, and we will continue to keep the drinking water safe, no matter what," Fort said in an emailed statement. He said there's much more work to do in studying, analyzing and implementing the right initiatives.

The regulators' letter to the Navy said models for groundwater flow and contaminants should be "reliable tools" that support key decisions as the parties decide how to protect against further leaks. The letter said models that are "scientifically rigorous and able to withstand legitimate scrutiny" will help the parties make decisions.

Marti Townsend, director of the Sierra Club of Hawaii, said the letter indicates "the Navy is no closer to knowing what is really going on" four years after the last leak.

"The Navy cannot locate the leaked fuel or accurately assess the risk to our groundwater. Instead they are pre-cooking the models to produce their preferred outcome," Townsend said in an email.

She called on lawmakers to require the Navy to install double-walled tanks at Red Hill within five years. She said the fuel should be moved if the Navy can't fix them to meet current safety standards.

The House environment committee is scheduled to consider a bill on regulations for the Red Hill tanks at a hearing Tuesday morning.

___

This story has been corrected to show the first name of the director of the Sierra Club of Hawaii is Marti not Martin.

News from © The Associated Press, 2018