Authorities were trying to determine when the spill at the bus depot on the Black Horse Pike in Washington Township began.
It was discovered early Thursday and was contained shortly after 3 p.m., NJ Transit spokesman John Durso Jr. said.
By about 6 p.m., 3,000 gallons of the spilled fuel had been recovered from the garage site, Durso said.
The DEP, U.S. Coast Guard, and state Division of Fish and Wildlife were working with Camden County officials to determine the extent of environmental damage, said Ralph Green, director of the Division of Environmental and Consumer Health Services, part of the county Health and Human Services Department.
Hajna said authorities had reports that some geese and ducks were affected by the fuel, but he did not have details.
Gloucester Township Mayor David Mayer said that the area's drinking water does not come from the lakes but that Grenloch Lake is used for fishing.
"Our concern is the safety and public health of our residents," Mayer said.
Grenloch and Blackwood Lakes drain into Big Timber Creek, which divides Gloucester and Camden Counties and which runs into the Delaware River.
Washington Township Fire Chief John Hoffman said booms were placed in Big Timber Creek between Bellmawr and Deptford Township.
Hajna said Big Timber Creek did not appear to be affected, but officials were monitoring it.
He said most of the diesel fuel flowed into a storm drain at the NJ Transit site and into a stream leading to Grenloch Lake.
"The response has been quick. Our guys feel that it's under control," Hajna said.
He said vacuums were being used to suck the diesel fuel out of Grenloch Lake. Absorbent pads also were placed in the waterways, he said.
NJ Transit hired Clean Venture Inc., an environmental-cleanup contractor based in Elizabeth, N.J., to contain the leak and clean up the waterways, Durso said. The company was at the scene about 11 a.m. to begin its assessment, Durso said.
