A multi-vehicle crash and truck fire paralyzed heavy pre-holiday traffic on Interstate 95 northbound through Fairfield and Westport Thursday afternoon, with the jam extending south nearly to the New York border.

The 3:30 p.m. crash near Exit 21 in Fairfield briefly shut down the entire highway, and for more than a half-hour, the highway's center and left lanes were closed as Fairfield firefighters battled the smoky fire.

The first engine company arriving on scene found a tri-axle dump truck in the middle lane of the highway, with its engine compartment and cab consumed in flames.

Northbound traffic quickly backed up to Exit 17 in Westport, but as the afternoon volume grew -- heavier than usual because of the impending July 4 holiday -- an hour later the backlog extended south to Exit 2 in Greenwich, according to the state Department of Transportation.

Firefighters reported there appeared to be no serious injuries. The accident is being investigated by State Police.