Norwalk Fire is investigating after a tractor-trailer car carrier went up in flames on Interstate 95 Saturday afternoon.
The fire caused the highway to shutdown northbound.
When firefighters arrived on scene, they found a tractor-trailer car carrier with the cab involved on fire along with three vehicles on the carrier fully engulfed in flames.
An additional engine and two tankers from the Darien and Noroton Heights fire departments were called to the scene.
Firefighters said six five gallon cans of foam were used to distinguish the fire.
No injuries were reported, firefighters said.
The highway reopened at about 4 p.m.