The oil spill occurred in the Delaware River near the Philadelphia International Airport and southern New Jersey, said U.S. Coast Guard officials.
"(Pennsylvania) Gov. Edward Rendell and New Jersey Governor Richard Codey continue to monitor the situation along with federal and state agencies here in the Commonwealth of Pennsylvania and the state of New Jersey," PEMA Director David Sanko said in a statement.
"Personnel from several state agencies including PEMA, the state Department of Environmental Protection and the Fish & Boat Commission have been on-site since early this morning."
Officials are still investigating the cause of the leak, but there is no threat to drinking water, according to Sanko.
"DEP has deployed booms in several creeks along the path of the spill," Sanko said.