Authorities say residents here were forced to evacuate their homes in Oklahoma City, Oklahoma, after a train derailed Tuesday evening.

About eight cars left a track owned by Stillwater Central Railroad on a stretch located north of Britton Road between Hiawasse and Sooner roads.

Authorities say some of the cars were tankers. Firefighters could not locate the engine that had been pulling the train.

An Oklahoma City Fire Department hazardous materials crew responded to the scene.

Reports are that molten sulfur was in the tanker that overturned.

Sulfur is a pale yellow nonmetallic element occurring widely in nature. It is used in gunpowder, rubber vulcanization, the manufacture of insecticides and pharmaceuticals, and in the preparation of sulfur compounds such as hydrogen sulfide and sulfuric acid.