The Honolulu Board of Water Supply is taking the U.S. Navy to court for refusing to cover the local agency’s costs following the 2021 fuel spill at Red Hill, as the agency tries to protect the groundwater that Oʻahu’s nearly 1 million residents rely on from further contamination.

The suit filed in federal court Tuesday puts the agency’s total costs at $1.2 billion to clean up remnants of the spill plus guard the island’s drinking water wells against additional contaminants spreading underground.

The Navy left the Board of Water Supply no choice but to seek those damages in court, Board Chair Nāʻālehu Anthony said in a statement, after “months of futile negotiations.”

The November 2021 spill contaminated the military’s own separate water system, too, which draws from the same underground aquifer complex and is used by more than 90,000 people to drink, bathe and clean. 

Thousands of those military personnel and their family members were sickened in the days that followed the spill, and the local water agency scrambled to isolate the island’s general water supply. That included shutting down the city’s nearby Hālawa Shaft and ʻAiea and Hālawa wells, which represented about 20% of Oʻahu’s water supply.

The incident was hardly a surprise. Multiple leaks had occurred at the 20 massive, underground fuel tanks buried at Red Hill in prior decades and Board of Water Supply Manager and Chief Engineer Ernie Lau had publicly urged the Navy for years to refurbish those tanks and better protect against future spills.

In the wake of the 2021 spill, Lau has repeatedly expressed frustration at the Navy’s heavily redacted reports on water testing and what he’s described as its limited transparency.

“This is not an issue that will be solved quickly or cheaply,” Lau said in a statement Tuesday. “Every action must be taken to protect the purity of Oʻahu’s water, and it is only right that the Navy assume financial responsibility for its actions.”

A Navy spokesperson Wednesday declined to address to the suit, saying it doesn’t comment on ongoing litigation.

Last month, many Red Hill military families expressed disappointment with the limited payouts they were awarded as part of a separate lawsuit against the Navy. At least 76 fuel release incidents have occurred at the Red Hill facility since the late 1940s, that lawsuit stated, potentially leaking more than a million gallons of fuel into the ground.