Description of the Occurrence

　　It was in a pickles plant. A worker entered the pickling tank to replace the pickled radish. Perhaps the worker breathed in some hazardous gases (a pickling tank may be filled with hazardous gases for the sulfur in the pickling water may produce dimethyl sulfide through biochemical metabolism and decomposition in the process of fermentation and sulfur dioxide, free ammonia and sulfureted hydrogen may be generated in the fermentation of pickled radish), and he fell in a faint in the pickling tank and disturbed the solution balance of hazardous gases in the pickling water. Other 4 workers who are working nearby entered the tank in succession perhaps to save the persons trapped, and they also fell in a faint in the tank and breathed in the pickling liquid. So a serious occupational disaster of poisoning shock and asphyxia occurred and resulted in 4 persons of death and one person of coma.

Cause Analysis

1. Direct cause: when the victims entered the pickling tank, they touched the dimethyl sulfide produced from the sulfur in the pickling liquid in through biochemical decomposition as well as the carbon dioxide and other suspected hazardous substances generated in the fermentation of pickled radish, thus resulting in poisoning asphyxia and shock.
2. Indirect Causes:
   1. Unsafe action: the concentrations of oxygen and hazardous substances in the pickling tank were not confirmed.
   2. Unsafe conditions
      • The pickling tank was filled with hazardous gases for the sulfur in the pickling water may produce dimethyl sulfide through biochemical metabolism and decomposition in the process of fermentation and sulfur dioxide, free ammonia and sulfureted hydrogen may be generated in the fermentation of pickled radish.
      • Proper measures were not taken to ventilate the pickling tank.
      • The workers did not wear proper breath protective equipment.
   3. Basic Causes
      • Rules on Safety and Health for Working in Confined Space were not formulated to guide the workers.
      • Necessary safety and health training was not provided for the workers who work in confined spaces.
      • Physical examination and health examination were not conducted for the workers in accordance with relevant provisions to understand heir physical conditions and dispatch work appropriately.
      • Insufficient safety consciousness

Countermeasures for disaster prevention

1. When making a worker conduct dangerous work in an anoxic environment, the employer shall prepare necessary measuring instrument to measure the concentration of oxygen in the air, and take measures to confirm the concentrations of oxygen and hazardous gases like sulfureted hydrogen in the air.
2. When making a worker conduct dangerous work in an anoxic environment, the employer shall perform ventilation appropriately to keep the concentration of oxygen in the air in the work place not less than 18%.
3. When making a worker work in an oxgen-deficieny dangerous place or an adjacent place, the employer shall mark the safety attentions on the entry of the work place obviously to make them aware of such matters, and prohibit other irrelevant workers from entering the oxgen-deficieny work place arbitrarily, and shall paste the notice of prohibition at the place easy to be seen by the workers.
4. When making an employee work in an oxgen-deficieny environment, the employer shall prepare respirator and other breath protection equipment, ladder, safety belt or lifesaving cord for the workers or rescuers to use on occurrence of emergency.

Disaster Sketch Map