A tanker trailer carrying thousands of pounds of a hazardous chemical burst into flames along an interstate highway, forcing the evacuation Saturday of several hundred people, officials said.

No one was injured and Interstate 12 was closed. Officials said they weren't sure when residents within a one-mile radius of the fire could return to their homes.Two hospitals in the area were put on standby for possible evacuations, but patients were not moved.

The truck carried 43,000 pounds of a granular form of sodium hydrosulfite, which is used as a commercial cleaner. It burst into flames on Interstate 12 about 25 miles north of New Orleans about midnight, said State Police Sgt. John Adams.

The cause of the fire was not immediately determined.