| Case Name |
Explosion of silicone products dissolved in an organic solvent during subdivision work |
| Pictograph |
|
| Date |
November 11, 1997 |
| Place |
Ichihara, Chiba, Japan |
| Location |
Chemical factory |
| Overview |
An explosion occurred at a silicone resin plant during subdividing of products dissolved in an organic solvent. Under conditions of insufficient ventilation of generated combustible gases, the insulating filter cloth was charged with static electricity, and a spark was discharged. |
| Incident |
At a manufacturing plant for silicone resin, an explosion and a fire occurred during subdivision operations for silicone resin dissolved in an organic solvent. Subdivision was being done into a pail can through a cloth filter, while products (silicone 26%, n- heptane 60%, toluene 14%) in a 200 L drum can was being tilted by a drum tipping machine. At this time, it ignited around the cloth filter, which was made of polyester, the fire spread to the drum can through an air hole, and an explosion occurred in the vapor phase in the drum can. The fire spread due to a leak of a remaining liquid in the drum can. One worker died, and another worker received a serious injury. |
| Processing |
Manufacture |
| Individual Process |
Filling and subdivision |
| Process Flow |
Fig2.Unit process flow
|
| Substance |
Heptane, Fig3 |
| Toluene, Fig4 |
| Silicone oil |
| Type of Accident |
Explosion, fire, leakage |
| Sequence |
About 13:25 on November 11th, 1997. Suddenly, an explosion and a fire occurred during subdivision work into a pail can.
13:28. Fire extinguishing activities by the neighborhood workshop started.
13:30. An emergency call to public fire fighters was made.
13:40. The private fire brigade started to spray water. Public fire engines arrived.
13:41. An ambulance arrived.
15:18. The fire was confirmed to have been extinguished. |
| Cause |
Local ventilation was being carried out around the workplace. However, ventilation was not sufficient, and a combustible gas-air mixture was generated around the pail can. When the accident happened, a dry air warning had been announced. Workers wore antistatic fatigues. It is considered that static electricity charged at the bottom of the filter cloth discharged to adjacent earthed objects (a pail can, etc.), igniting the peripheral combustible gas-air mixture. |
| Response |
Fire extinguishing activities were carried out using a fireplug. |
| Countermeasures |
Countermeasures against generation of a combustible gas-air mixture and static electric sparks are to be carried out with certainty. |
| Knowledge Comment |
Where solvent vapor is present, a combustible gas-air mixture is likely to be generated. There is an explosion hazard. Sufficient attention is needed even in subdivision operations. With ventilation lowering the fuel gas concentration, countermeasures against ignition sources such as static electric sparks are also indispensable. |
| Background |
It seems to have been a basic factor of the accident that the subdivision operations were carried out under a condition where ventilation of combustible gases and control of static electric sparks were insufficient. |
| Incidental Discussion |
It seems from the report that the plant and operations were likely to cause an accident. How did the manager and the supervisor grasp the actual situation, and try to improve them? There were other examples of accidents caused by electrostatic charge in using an insulating filter cloth. |
| Reason for Adding to DB |
Example of explosion caused due to mal ventilation for subdivision work of an organic solvent solution |
| Scenario |
| Primary Scenario
|
Poor Value Perception, Poor Safety Awareness, Inadequate Risk Recognition, Carelessness, Insufficient Understanding, Insufficient Recognition of Risk, Insufficient Analysis or Research, Insufficient Practice, Lack of Imagination, Planning and Design, Poor Planning, Poor Design, Secondary Damage, External Damage, Explosion/Fire, Bodily Harm, Death, Bodily Harm, Injury, Loss to Organization, Economic Loss, Manetary Damage 100 million yen
|
|
| Sources |
Japan Industrial Safety and Health Assoc. Safety and health information center. Case of labor accident. No.100203. Explosion of silicone product during subdivision work. The Japan Industrial Safety and Health Assoc. home page.
Fire and Disaster Management Agency. Fire during subdivision operation into a pail can. Accident cases of the dangerous material. 1997. pp.58-59.
Material of the Japan Industrial Safety and Health Assoc..
|
| Number of Deaths |
1 |
| Number of Injuries |
1 |
| Physical Damage |
A cable duct and a floor were destroyed by fire in the third factory. |
| Financial Cost |
¥ 100 million (Fire and Disaster Management Agency) |
| Multimedia Files |
Fig3.Chemical formula
|
|
Fig4.Chemical formula
|
| Field |
Chemicals and Plants
|
| Author |
DOBASHI, Ritsu (School of Engineering, The University of Tokyo)
TAMURA, Masamitsu (Center for Risk Management and Safety Sciences, Yokohama National University)
|
|
