Pennsylvania Department of Environmental Protection emergency responders joined the US Coast Guard and other members of an incident management team to assess the release of about 3800 litres of oil into the Delaware River.

The spill was about 1.5km south of the Commodore Barry Bridge.

Monroe Energy promptly reported the spill, which occurred when a pipe ruptured as crews were offloading crude oil.

The company took the necessary actions to limit the damage from the spill.

Coast Guard Sector Delaware Bay personnel received notification of the spill at about 1pm after the National Response Centre sounded the alarm.

A boom was deployed to contain the oil while responders used skimmers and vacuums to remove the oil from the water.

A pollution USCG pollution response team is on scene to monitor the situation.

DEP secretary Chris Abruzzo said the quick response to the incident and the cold weather had helped.

"While any spill into our waterways is unacceptable, reporting protocols were followed and we were able to respond quickly and effectively," he said.

"The frigid weather and quick containment response have helped to minimise the impacts of the incident.

"DEP staff are on the scene and will continue to monitor and assist with the clean-up until it has been completed and we will review the cause of this incident to determine whether additional action is warranted."