Undated (AP) _ About 1,500 Culver City, Calif., residents were ordered to evacuate after a tanker truck ruptured on the San Diego Freeway Tuesday, and about two dozen New Hampshire families fled their homes when a truck leaked a toxic chemical on a highway.

The tanker truck overturned, ruptured and caught fire at about 4:18 a.m., closing the freeway and forcing evacuation of neighborhoods about 10 miles west of downtown Los Angeles when a chemical cloud drifted several blocks.

Rush-hour traffic was backed up for miles.

The area was reopened at 8:30 a.m. when officials determined the chemical in the tanker was a relatively harmless liquid sulfur, said fire battalion chief Bob Dewberry.

Several people complained of breathing difficulties, however, Dewberry said. Fire spokesman Jim Wells said about 1,500 people were affected by the evacuation order.

The sulfur compound had been loaded at the Chevron Ortho Division yards in El Segundo for shipment to Cawelo, Calif., firefighters said.

In Pelham, N.H., some residents reported feeling ill and at least eight sought treatment at area hospitals, said state police Capt. Don Anderson. Fire officials said two firefighters were also treated for breathing difficulties and released.

About two dozen families were evacuated as a precaution because officials did not know what kind of chemical had leaked from the truck, which drove on toward Alabama.

The company that owned the truck said the substance was paint residue and cleaned up the spill Tuesday afternoon.

Officials said the driver finally was contacted by telephone in Pennsylvania, where he said the truck no longer appeared to be leaking.