Two 18-wheel trucks collided on I-10 early Tuesday, touching off an explosion and chemical fire that forced the evacuation of about 600 people, state police said.

Five people riding in the two trucks were injured, none seriously. They were taken to a hospital, where four were admitted.The collision occurred in the eastbound lane of the I-10 bridge over the Mermentau River on the Jefferson Davis-Acadia Parish line about 6 a.m. The highway was closed as the wreckage involving 6,600 gallons of naptha and toluene was allowed to burn itself out.