Four manual laborers have died after being asphyxiated in a culvert in northwest China on Thursday.
Seven workers were repairing pipelines in the culvert of the Xichawan Reservoir in Haidong City, Qinghai Province on Thursday afternoon, when there was a sudden loss of oxygen in the narrow passage. One worker managed to get out and alerted police, according to the local publicity department.
The remaining six were all pulled out by 5:10 p.m., but four died in hospital. The other two are in stable conditions.
The culvert was built in the 1960s and is very leaky, authorities said.