It happened before 4:00 p.m. at mile marker 46 between the Lehigh Valley and Quakertown exits in Lower Milford Township.
Sources tell Action News a camper being pulled by another vehicle caught fire.
An image sent to Action News by a motorist passing by the accident showed a fiery scene involving an SUV and flames coming from what appeared to be the camper lying on its side.
No one was injured in the accident.
All southbound lanes were blocked as firefighters extinguished the flames and crews began to clear the wreckage.
Images from Chopper 6 HD showed a line of cars backed up for miles on the southbound side.
Motorists were seen getting out of their vehicles and sitting along the side of road as they waited for the accident scene to be cleared.