SHIJIAZHUANG - Six people were suffocated to death when slag water leaked in an industrial plant and mixed with rainwater in North China's Hebei province on Tuesday morning, local authorities announced.

The accident occurred at 7:12 am at the Xiaojue Branch Plant of Shijiazhuang Sanhuan-Smelting Co., Ltd. in Xiaojue township, Pingshan county, triggering high temperatures and stifling two people to death at the scene, the county government said.

Another four people were rushed to hospital, where they died at around 10:30 am.

Seven workers were at the scene when the leakage occurred, and one escaped unscathed, said publicity officials with the Shijiazhuang municipal committee of the Communist Party of China.

By Tuesday afternoon, the legal representative of the plant had been detained, officials said.

Investigators have been dispatched to the scene to look into the accident.