LANZHOU, Feb. 6 (Xinhua) -- At least six people were injured Tuesday in an explosion at a China National Petroleum Corporation (CNPC) chemical plant in Lanzhou, capital of northwest China's Gansu Province.

The blast occurred at about 3:15 p.m. when equipment exploded in a workshop of a synthetic rubber plant and fire broke out, according to local work safety authorities.

Firemen and rescuers rushed to the site, but the fire was still raging at press time.

The injured have been hospitalized and their condition is stable, the firemen said.

Police are investigating the cause of the accident.