The substance that caused the sheen on the Potomac River and contaminated a waterfowl sanctuary was transformer mineral oil that spilled in January, Dominion Virginia Power said Friday evening.
All oil samples collected from the contaminated sanctuary came from a Dominion transformer station in Crystal City, the U.S. Coast Guard said. So far, 21 wild geese and ducks have died at Roaches Run Waterfowl Sanctuary as a result of the spill, and 32 have been rescued and decontaminated.
The spill, which stretched eight miles along the Potomac River from just about National Airport down to the Wilson Bridge, was spotted in the water Feb. 3 and believed to be caused by snow runoff after the blizard, the Coast Guard said, but when it continued Feb. 5, unified command was set up.
A 13,000-gallon spill at the Dominion transformer station took place the week before.
The EPA will decide whether to take action against Dominion. The utility company could have to pay for the entire cleanup and fines.