SHIJIAZHUANG, June 16 (Xinhua) -- Five people died following an illegal waste dumping accident in north China's Hebei Province, local authorities said Friday.

The accident took place Friday morning when five people passed out while dumping industrial waste water into a river in Wuji County.

Four of them died on the way to the hospital and one died in the hospital.

Toxic gas produced during the dumping process led to their deaths, according to local authorities.

Seven suspects involved in the accident have been put in police custody.

The investigation continues.