The incident was reported around 8:25 a.m. Tuesday at Blue Knight Energy Partners located at 201 Water Street in Gloucester City.
An official from the New Jersey Department of Environmental Protection told Action News an expansion tank ruptured, spilling a total of 300 gallons of oil.
Half the spilled oil was held in a containment area surrounding the tank, the official said.
The remaining 150 gallons spilled out of the holding area and ran into storm drains that empty into the Delaware River.
The official said Blue Knight has hired Clean Harbors, Inc. to clean up the spill.
The Coast Guard and environmental officials remained on the scene to make sure the cleanup was being done properly.
There were no injuries reported and no reported risk to people or wildlife in the area.