An oil tank exploded Tuesday, leaving seven workers injured in south china’s Guangdong Province, police said.

The incident occurred at about 1 p.m. at the Sinopec Group branch in Huangpu District in GuangZhou, capital of Guangdong, leaving seven injured at the scene, three of them with serious injuries, police said.

All the injured have been hospitalized.

The explosion triggered a fire which was put out in ten minutes, according to official sources.

An investigation into the cause of the explosion is underway, police said.