DALIAN — Eight villagers died while cleaning a sewage discharge outlet Friday in Dalian, a port city in Northeast China's Liaoning province, local authorities said.

The accident happened at around 8:30 am in Yanchang village of Longtou community in Lushunkou district, the press office of the district's Party committee said in a statement.

It said the cause of the deaths is under investigation.

Exposure to toxic sewer gas such as methane and hydrogen sulfide can be fatal.