An explosion ripped through a chemical plant in southwest China's Guizhou Province Thursday, killing at least five people and injuring four others, local authorities said.

The accident took place at about 9 a.m. at the plant in Xingyi, in the Bouyei-Miao Autonomous Prefecture of Qianxinan, said Chen Gang, director of the prefecture government's emergency response office.

"The explosion occurred when workers were repairing chemical material pipelines," he said.

The injured people had been rushed to hospital. "We are investigating the cause of the accident," he added.