FORT SHAFTER, Hawaii — The 20 massive tanks that make up the Red Hill Underground Fuel Storage Facility on the outskirts of Honolulu are an engineering marvel.

Embedded deep in a volcanic mountain in the early years of World War II, the tanks can hold a quarter-billion gallons of fuel to feed the ships, submarines and aircraft at nearby Joint Base Pearl Harbor-Hickam.

The future of the facility, a National Historic Civil Engineering Landmark since 1995, is at a crossroads. The Navy proposes a multimillion-dollar improvement plan to extend its life for at least another 25 years, but the tanks, entombed in volcanic rock, defy any feasible method of retrofitting. Conservationists and some civic leaders say the massive amount of fuel it stores poses a threat to Honolulu’s water supply and that the facility must be made failsafe or be entirely abandoned.

“The Red Hill fuel facility is a critical national security asset,” Rear Adm. Robert Chadwick, commander of Navy Region Hawaii, said during a public hearing earlier this month.

“It provides the daily fuel requirements here in Hawaii for our Navy, Air Force and Hawaii National Guard, and it also provides strategic reserves for our joint forces throughout the Indo-Pacific theater. This is at a time when our potential adversaries around the world continue to be more and more aggressive.”

The tanks, however, were built over a vast aquifer that supplies drinking water to greater Honolulu, and the risk the tanks pose became clear in 2014 when about 27,000 gallons of jet fuel spilled from one. There have been numerous other smaller leaks during the past couple decades, and petroleum-based chemicals have been detected in groundwater monitoring wells.

In 2015, the Navy, U.S. Environmental Protection Agency and Hawaii public health officials signed an enforcement agreement directing the cleanup of the leak.

The so-called administrative order of consent also required the Navy, along with the Defense Logistics Agency, to research and evaluate upgrades to the existing tanks to minimize the threat of future leaks.

In September, the Navy and DLA proposed several possible upgrades, including the removal and replacement of the existing inner steel liner, creation of a double wall for each tank or insertion of entirely new tanks within the existing ones.

The Navy’s preferred upgrade, based on what it calls the “best available practicable technology,” would consist of coating the inside of the tanks and eliminating the number of nozzles on the system, which are particularly vulnerable to leaks. It would also step up testing and monitoring on the layers of rock, concrete and steel that separate tanks from the aquifer.

The document touted the $162 million the Defense Department has spent improving Red Hill since 2015, with another $256 million slated for improvements over the next five years.

Some residents and Hawaii officials are underwhelmed by the Navy’s plan.

“Basically, the Navy has chosen the least protective, least costly and least ambitious option,” Jodi Malinoski, a policy advocate with Sierra Club, said during a public hearing Oct. 17 at the Hawaii Capitol.

“We’re calling for the Department of Health and EPA to reject this report and to essentially direct the Navy to relocate their tanks to locations that are not above our aquifer,” she said.

At the same hearing, the aquifer was described as “irreplaceable” by Ernie Lau, chief engineer with the Honolulu Board of Water Supply.

“We want to support the Navy mission, but we think it can be done in other ways and other alternatives,” he said.

‘Remarkable’ engineering feat The Red Hill Underground Fuel Storage Facility was conceived in a shroud of secrecy at the cusp of World War II, according to documents supporting its nomination as a landmark.

As military confrontation with Japan loomed in the late 1930s, the U.S. Navy recognized that the above-ground fuel tanks scattered around Pearl Harbor would be vulnerable to attack.

Initial plans called for burying four 300,000-barrel storage tanks, each about 1,100 feet long and 20 feet wide. They would be set horizontally deep into the earth, far out of reach by enemy aircraft.

The site chosen to bury the tanks, Red Hill, was a long ridge of volcanic rock stretching from Oahu’s Koolau mountain range and almost reaching Pearl Harbor. The buried tanks would sit high enough in the mountain that fuel would flow by gravity to the naval base.

By the time project designing began, the Navy had expanded the number of tanks needed to 20, and engineers began preparing for the massive amount of rock that would need to be blasted and scooped out of the mountain.

Consulting engineer James Growden is credited with the design for placing the 20 tanks vertically into the mountain instead – an idea he first sketched out on a cocktail napkin at a Waikiki hotel, according to the lore.

Excavating horizontal tunnels of loosened rock is time-consuming and requires many workers and heavy machinery, all crammed into a tight space.

Growden’s design instead called for boring a hole from the top of the mountain down through the imaginary centerline of a tank. A horizontal shaft would be bored at the base of the mountain and connected to the vertical shaft.

Excavation would then begin at the top, and every shovelful of dirt and rock would be tossed down the bore to a conveyor belt far below that whisked the material to a nearby aggregate plant. The design required fewer workers and significantly cut costs and construction time.

Nearly 3,000 men worked around-the-clock for almost three years before completing the project in September 1942, which the landmark nomination described as “one of the most remarkable engineering feats of

World War II.” Seventeen workers died getting it built.

The 20 tanks — each 100 feet wide and roughly 250 feet high — stand in two rows of 10. Their tops are 100 to 175 feet below ground.

‘It just won’t work’ Critics of the Red Hill fuel tanks have for years urged the Navy to retrofit them to ensure they will be leak proof. But the tank system’s greatest strength — its impregnability to outside force — also makes adding a buffer layer near impossible.

Steven Linder, a program manager for the EPA’s underground storage tank program, said at a public hearing earlier this month that both the EPA and Navy had brought in industry experts, including one who formerly managed Chevron’s fuel storage, to review technologies for retrofitting.

“Unfortunately, the Red Hill tanks are quite unusual — much taller and larger than what you usually see,” he said. “So, a lot of technologies that were designed for shorter, above-ground tanks that have much lower pressure on them can’t be used at Red Hill. It just won’t work.

“These tanks are mined into the mountain, into solid rock, over a huge area. There’s no technologies that allow us to basically get in there and around these tanks to make the area around the tanks impermeable.”

The administrative order of consent requires all the tanks be upgraded to the “best available technology” by the year 2037 or no longer hold any fuel by that time, Linder said.

The EPA is now considering the Navy’s proposal to extend that deadline to 2045, he said.

Critics say there is too much risk to wait that long.

The Honolulu City Council is set to vote Nov. 6 on a resolution calling for either an upgrade using a secondary containment tank or, if that is not feasible, relocating fuel storage to somewhere away from the aquifer.

The Honolulu Board of Water Supply has voiced strong support for the resolution.

“Everything fails no matter how much upgrading you do, no matter how much inspection you do,” Melanie Lau, a member of the state’s Fuel Tank Advisory Committee, said at the Capitol hearing.

“I can understand how the Navy would want to hold onto something that they have; it’s wonderful, great,” she said. “However, we only have one aquifer. We live on an island. We don’t have a choice.”

olson.wyatt@stripes.com Twitter: @WyattWOlson

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