DALIAN, May 19 (Xinhua) -- 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 a.m. 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.