Eight persons were killed and two fell ill from toxic gas on Friday while cleaning a sewage discharge outlet in Dalian, a port city in China's Liaoning province, authorities said.

Villagers and workers fell unconscious while entering a sewage pool at a kelp processing plant to clean the blocked outlet in Yanchang New Village in Lushunkou district, Xinhua news agency cited the district's Party committee as saying in a statement.

Other villagers trying to save them also inhaled the gas and fell into the pool, it said.