On May 11, Navy personnel at Naval Station Air Station Oceana in Virginia Beach, Virginia made an error in routing aviation fuel from a tank barge into an on-shore storage facility, spilling 100,000 gallons – including 25,000 gallons that made its way onto land and water off-base. The Navy announced Friday that it is taking disciplinary action for the personnel involved, including enlisted sailors and senior officers.

The spill was the largest in the base’s history. So far, it has cost the service about $3.8 million in cleanup costs, including $180,000 for the fuel itself and $180,000 for temporary relocation for 177 affected residents. The Navy says that cleanup is now substantially complete, and that environmental monitoring shows that citizens were not exposed to health risks. Some of the base’s neighbors reported minor, temporary symptoms of exposure to distillates; one compared the air quality at the time of the spill to “sticking your head in a fuel drum.”

In mid-May, Rear Adm. Jack Scorby, commander of Navy Region Mid-Atlantic, told media that the cause of the accident came down to a switch left in the wrong position. The improper routing sent fuel from the tank barge into a 2,000 gallon tank – not an 880,000 gallon tank, as intended. The tank quickly overflowed, but the spill was not noticed for about 16 hours.

On Friday, Rear Adm. Scorby told press that the Navy is disciplining nine unnamed servicemembers and one civilian for the accident. He added that the base has changed its operating procedures to prevent future spills, installing overflow-prevention devices and increasing patrols. “We have been working hard to make a terrible situation better,” Scorby said. “We take these responsibilities seriously and we hold people accountable for those who don’t.