Case Ditails

Scenario
Case Name Explosion due to a runaway reaction from operation by misunderstanding of the reaction progress during preparation of organic peroxide
Pictograph
Date January 22, 1992
Place Harima, Hyogo, Japan
Location Chemical factory
Overview During manufacturing organic peroxide (1,3- bis- t- butylperoxideisopropyl benzene), a operator was convinced that the performed process was alkali-washing, but it was actually a second order reaction. He thought that the temperature was low for washing, and ran warm water at 70 °C into the jacket. As a result, a reaction temperature rose and an abnormal decomposition reaction was caused. Therefore, cracked gas filled the jacket, exploded, and burned on contacting ignition sources such as electrical device. The cause of the accident is inadequate communication at a shift change.
Incident Cracked gas was generated during manufacturing organic peroxide (1, 3- bis- t- butyl peroxyisopropylbenzene). Afterwards it exploded and burned.
Processing Manufacture
Individual Process Reaction
Process Flow Fig2.Unit process flow
Chemical Reaction Oxidation
Substance 1,3- bis(t- butylperoxyisopropyl)benzene, Fig3
Type of Accident Explosion, fire
Sequence 1. On January 21st, 1992. The afternoon shift finished the first order reaction and it progressed to the second order reaction.
2. Operation was handed over to the night shift during the second order reaction.
3. An operator of the night shift judged that the reaction temperature was low, and ran warm water at 70 °C into the reactor jacket.
4. 01:35 on January 22nd. The cracked gas spouted out from the manhole of the reactor and exploded on contact with ignition sources.
Cause The cause of the accident was a human error. Although it was a second order reaction, the operator was convinced it was alkali washing. Therefore, he thought that the temperature was low, and ran warm water of 70 °C into the jacket. As a result, the reaction temperature rose, and an abnormal decomposition reaction was generated. Therefore, cracked gas filled the jacket and exploded on contact with ignition sources such as electrical devices and burned.
Response Fire fighting by a private fire prevention organization.
Countermeasures Strengthened detection and monitoring instruments such as a combustible gas concentration detector.
Proper communication at a shift change.
Strengthened education to make employees understand properties of hazardous materials.
Knowledge Comment If communication is bad when shift workers are changing, there can be serious consequences.
Preparing and maintaining a system for reliable communication are tasks of the management.
Background 1. The system of a shift change of operators is thought to be defective. Although the accident occurred because of an error by an operator of the latter shift, the real cause was in the defective shift change. Not only oral briefings but also handing over of a notebook should be done, and the details should be recorded. Moreover, a system that enables operators to confirm every doubt on operation is required.
2. There seems to be no system to confirm the operation state. Many processes in a chemical plant progress in a vessel, and only temperature, pressure and so on can be observed from outside. In a batch reaction system, some operations are done in the same vessel. It is important to understand the present state of the vessel. It is thought that this accident would not have happened if there had been a signboard stating "second order reaction" at a position that was easily seen on the reactor.
3. It is felt that education is required. Some processes are carried out in the same reactor. This is hazardous and there is a possibility that off-specification products will be produced if the operation condition is different from what is appropriate to the process. It is important to make workers understand the present situation using a signboard, and to give the reason for the working conditions. It is also important to have communication and consultations among shift members.
In this case, the worker might have consulted before acting if he was not alone. "Report, Communication, and Consultation" is the basis of education.
"Report, Communication, and Consultation" are keywords to make work progress smoothly, efficiently, and safely.
Thinking about the three items above should be reflected in the overall management system and discipline.
Incidental Discussion The well-known signboard system of Toyota Motor Corporation is one example that can be introduced into the chemical industry, because the contents of work that is out of sight can be confirmed.
Reason for Adding to DB Example of explosion and fire caused due to misunderstanding of the process by an operator
Scenario
Primary Scenario Organizational Problems, Poor Management, Slackness of Management, Carelessness, Insufficient Precaution, Wrong Taking-over, Misjudgment, Misperception, Mis-Convincement, Regular Operation, Erroneous Operation, Reverse Operation, Bad Event, Chemical Phenomenon, Abnormal Reaction, Secondary Damage, External Damage, Explosion, Bodily Harm, Injury, 3 person injured, Loss to Organization, Economic Loss, Manetary Damage 44 million yen
Sources Fire and Disaster Management Agency, Explosion of benzene reaction chambers 1.3- bis- t- butylperoxideisopropyl, Accident cases of dangerous materials, 1992, pp.110-113.
A fire caused by explosion at a hazardous materials manufacturer in Hyogo Prefecture. Kakogawa, Modern fire-fighting, No.361, p.35(1992).
Masahide Wakakura, Yoshiaki Iiduka, Accident prevention techniques for runaway reaction, Research on disasters, 25, pp.301-311(1994).
National dangerous material safety association. Fire caused following explosion by the generation of decomposition reaction in organic peroxide manufacturing plant reactor, One hundred cases of accidents at hazardous facilities, No.2, pp.40-41(1994).
Number of Injuries 3
Physical Damage 80 square meters of an ethylene derivatives factory burned down. 24 facilities were destroyed in the factory. Windows of 92 private houses in the vicinity were damaged.
Financial Cost ¥ 44 million. (Fire and Disaster Management Agency).
Multimedia Files Fig3.Chemical formula
Field Chemicals and Plants
Author OGAWA, Terushige (Graduate School of Environment and Information Sciences, Yokohama National University)
TAMURA, Masamitsu (Center for Risk Management and Safety Sciences, Yokohama National University)
Scenario