VIRGINIA BEACH, Va. (WVEC) -- The Navy says the cost of cleanup efforts following a jet fuel leak was nearly $4 million.

Back in May, 94,000 gallons of fuel spilled at Naval Air Station Oceana after someone left a switch in the incorrect position, causing an overflow. Much of it spilled into neighborhoods and waterways, and strong fumes from the spill forced about 50 families in the area to re-locate, some for as long as two weeks.

Almost 1,500 animals died, mostly fish.

On Friday, Rear Admiral Jack Scorby said the cost of cleanup so far is $3.8 million. Nine military personnel have been "disciplined," and procedures in the wake of the accident have been overhauled.

Scorby described the personnel's actions as being a "dereliction of duty," and that punishments could range from possible losses in rank to court martial referrals. He declined to name those involved but said they include junior enlisted sailors and senior officers.

Navy's update on NAS Oceana fuel spill, 6/23/17 by 13News Now on Scribd

PHOTOS: Jet fuel spill at NAS Oceana

The Associated Press contributed to this report.