The remains of the five victims have been retrieved from the construction site of the sewage disposal plant. There is slim hope of survival for the missing one, sources said.

The mishap occurred at around 10:00 p.m. Wednesday at one of the two sewage tanks of Qiaodong Sewage Disposal Plant in Shijiazhuang, burying ten people working inside the tank. Only four workers have been rescued from the debris.

The rescue operation was "very difficult", and it is hard to determine the exact location of the buried workers because of the complicated situation inside the tank, said the sources.