A tanker carrying approximately 7,000 gallons of diesel fuel backed into a dumpster at the Mirant Potomac River Generating Station on N. Royal St. early Tuesday morning, spilling some of its contents into storm drains connected to the Potomac River.

Alexandria, Arlington and DC officials, worked with the EPA and Mirant to curb the damage on the ground and eventually contained the spill, which occurred around 6:00 am.

The exact environmental impact was still to be determined early Wednesday, but officials said there were reports from fireboats and helicopters of a visible sheen in the river.

We do know that there has been some product release into the river, said Fire Chief Adam Thiel. We just dont know how much and we dont know the extent of the potential spill.

The Mirant plant is familiar with Alexandria pollution issues. Some citizens and city officials believe the plant emits harmful pollution that will cause long-term health effects in the area. The plant currently awaits a decision from Virginias Department of Environmental Quality and the Air Pollution Control Board on a permit that, if passed, would merge the plants smokestacks, a process which Mirant spokesmen say will reduce harmful emissions.