The Navy has submitted a tank upgrade study for the Red Hill Bulk Fuel Storage Facility that examines six options ranging from enhancing current maintenance and inspection to creating a carbon steel tank within a tank.

The new report suggests that the more ambitious proposals would be costly and complex.

The Red Hill fuel farm, a national historic civil engineering landmark, was completed in 1943 and consists of 20 vertically placed underground tanks that are between 238 feet and 250 feet tall and cumulatively hold up to 250 million gallons of fuel for military activity across the Pacific.

In January 2014, the Navy reported a 27,000-gallon leak at Tank 5 that it later said was the result of poorly performed work by a contractor and insufficient oversight by the Navy.

A resulting “administrative order on consent” requires the Navy to research and evaluate structural upgrades to the tanks, which are constructed of concrete with quarter-inch steel plates forming a liner around the midsection and tops of the tanks and half-inch steel plates around the bottom of the tanks.

The tanks are located 100 feet above the groundwater aquifer.

“The Navy study provides in-depth conceptual design information for six upgrade options, but does not recommend one option,” said a release from the U.S. Environmental Protection Agency and state Department of Health.

SINGLE-WALL tank options include:

>> repair and restoration of existing tanks;

>> restoration plus interior coating; and

>> removal of steel liners and installation of new steel liners with interior coating.

Double-wall tank/secondary containment alternatives include:

>> composite tank (double wall) carbon steel tank with interior coating;

>> composite tank (double wall) stainless steel tank; and

>> tank within a tank (carbon steel) and full exterior and interior coating.

The Navy redacted all cost data from the publicly released version of the study, saying that “due to federal contracting regulations” the upgrade costs cannot be revealed. Also blacked out are all references to long-term costs for the tank plans.

“Some information, including cost estimates, is redacted to protect the integrity of the procurement process and to ensure that the government receives the best value in the competitive bidding environment,” Navy Region Hawaii said in an email. “However, the solicitation for each alternative will include a dollar range of the government’s estimated total costs.”

The joint news release said the EPA, Health Department and Navy will use the study, along with community input and other studies, to select a final upgrade option.

A public information workshop will be held in the spring to explain the report and for the three entities to respond to community questions and concerns. After that, the Navy will propose a tank upgrade option and a second public meeting will be held before the Navy plan is approved or rejected, the EPA and Health Department said.

The tank study is available at 808ne.ws/RHstudy.

Rear Adm. Brian Fort, commander of Navy Region Hawaii, said in a recent editorial that since 2006 more than $200 million has been spent to continue modernizing Red Hill.

Tests at monitoring wells and other sources “confirm our drinking water continues to be safe to drink,” Fort said.

For the more ambitious plans, there are “limited firms that specialize in tank fabrication,” the Navy said. “Companies may bid high on the safety/risk factor alone. It will have to be worth their efforts monetarily to accept the risk.”