The military has found 15 tiny holes in the tank, which is roughly the size of a 20-story building, according to a Navy press release issued Saturday. Three of these holes were reported earlier in the month.
The holes were identified after the Navy performed vacuum box testing in areas where a prior visible inspection found 45 areas inside the tank that looked suspect. Vacuum testing determines if air can flow through a tank wall, indicating that fuel would also be able to escape.
The holes were located in welding repairs performed during recent tank maintenance.
“We’ve identified a cause of the fuel release from Tank 5 by visual inspection of the interior of the tank and follow-up non-destructive testing of anomalies identified during visual inspection,” Capt. Mike Williamson, chief engineer for Navy Region Hawaii, said in the press release. “We will consult with our experts and determine if the combination of these defects could account for a loss of up to 27,000 gallons of fuel.”
The Navy plans to begin testing the tank’s pipes next week.
Lab tests indicate that drinking water sources in the vicinity of the Red Hill facility remain safe to drink, according to the press release.
The leak at Tank 5, one of 20 underground tanks at Red Hill, has prompted heightened concern among regulators that decades of past leaks, leading to groundwater contamination around the facility, could pollute wells in the area that supply one-fourth of Oahu’s drinking water.