A fuel oil spill over a four-mile stretch of road in Franklin Township Sunday night remains under investigation.

The incident occurred just before 7 p.m. when a vehicle towing a trailer with a home heating fuel tank on the back of it leaked and spilled onto the roadway, according to Sgt. Shawn Hilbert of the Lehighton state police barracks.

Hilbert said police aren’t sure if the tank tipped over in the trailer or not, but the heating oil that was in the trailer leaked out over about a four-mile stretch of road.

The spill is believed to have started along Canal Street, and continued all the way to 3730 Long Run Road. Franklin Township Assistant Fire Chief Kevin Lilly said that he fire department applied about 10 bags of Speedy Dry to the roadway.

“We did what we could,” Lilly said. “We got the immediate problem areas.”

Lilly said the state Department of Transportation was notified of the incident and arrived on scene.

ilbert said the area was shut down in places while the absorbent was being applied to the roadway.

He said they were able to use the absorbent material in places where the fuel spill was the worst, adding it was more of a safety issue than anything.

Hilbert said the matter remains under investigation.

Franklin Township Fire Police also assisted with traffic control.