Unloading acid, wearing protective equipment, distress and injury

1. After the accident

In the summer of 2000, three loading and unloading workers unloaded dangerous chemical sulfuric acid at a railway freight yard in Anhui Province. According to the normal procedure, they first connected the upper discharge pipe of the tank truck with the flange of the transfer pipe and pressurize the tank. When the pressure reached the required level, sulfuric acid still did not flow out, and then the deflated decompression was used to open the large cover of the notch for inspection and found that the discharge pipe in the tank was blocked. So three people dismantled the flange and used a steel pipe to insert it into the discharge pipe to clear it. When the discharge pipe was opened, a white foamy liquid was sprayed in the pipe, which was more than 3 meters long and splashed on the body and face of the three people standing on the tank. Because 3 people did not wear protective masks, when the eyes of 3 people were dark, eye pain was unbearable, sent to the hospital after washing with water, check for alkali damage. After more than six months of treatment, the visual acuity of all three people was below 0.2, and the lacrimal glands were damaged.

2. Causes of accidents

After investigation, the sulphuric acid tank was previously used to contain liquid caustic soda and was cleaned prior to sulphuric acid. According to the analysis, the discharge pipe on the tank has not been cleaned in place, and the attached liquid caustic soda plugs in the lower part of the discharge pipe. When it is dredged, the alkali, reaction brine and acid are sprayed successively due to the effect of sulfuric acid pressure.

On the one hand, this accident was caused by the tank cleaning being not in place. On the other hand, the reason was that the acid unloader did not wear a protective mask as required. In this dangerous situation, there is no protection.

3. Accident handling and prevention

After the accident, the freight yard organized related departments to conduct investigations and analysis, to implement the treatment of the wounded, to clarify the responsibilities, to educate the employees, and to carry out safety propaganda activities.