Confined Space Entry and Rescue

Confined Space

Refers to a limited space that is relatively isolated from the outside world, has restricted entry and exit points, poor natural ventilation, and is large enough to accommodate a person entering to perform non-routine, non-continuous operations.

Case Study I
On May 21, 2004, during operations to clear a sewage inlet in the collection well of a sewage lifting pump station in a Qingpu industrial park, the operator worked without wearing any personal protective equipment. After the first entrant collapsed, three other operators entered to rescue him and unfortunately collapsed in succession, resulting in 4 fatalities.
Cause of Death: Hydrogen sulfide poisoning.
Accident Causes:
1. No gas testing was conducted prior to entry;
2. No personal protective equipment was worn;
3. Lack of pre-job training and emergency rescue training. 

Case Study II
On May 31, 2006, at the Shanghai Yangyang Soybean Food Company in Baoshan, two workers collapsed inside a sewage treatment equalization tank while replacing the pump screen, resulting in 2 deaths.
Cause of Death: Hydrogen sulfide poisoning. The wastewater and residue generated during production contained sulfur organic compounds, which decomposed by bacteria to produce hydrogen sulfide gas. Post-incident measurements showed a hydrogen sulfide concentration of 110mg/m3 in the equalization tank.