| Case Name |
Explosion caused due to aged deterioration of equipment at an initiative explosive factory |
| Pictograph |
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| Date |
June 12, 2002 |
| Place |
Nobeoka, Miyazaki, Japan |
| Location |
Explosive factory |
| Overview |
An explosion occurred in a granulation drier at a factory manufacturing initiative explosives for electric detonators. Either of the following two causes was considered to be a cause for the accident. The explosive, which entered through a crack at the drier, ignited due to friction, to cause detonation. Or, the explosive ignited and burned in the granulation process due to increasing friction sensitivity from rust contamination, to cause detonation. It occurred due to insufficient daily checks of age deterioration of facilities or due to contamination of foreign materials. It seems to raise a problem of facilities management and operational control. It is important to carry out hazard management. |
| Incident |
Diazodinitrophenol, which is an initiative explosive of an electric detonator, exploded in a drying and granulating process. |
| Processing |
Manufacture |
| Individual Process |
Drying and desiccation |
| Process Flow |
Fig2.Unit process flow
|
| Substance |
Diazodinitrophenol, Fig3 |
| Type of Accident |
Explosion |
| Sequence |
Diazodinitrophenol exploded during usual operation. |
| Cause |
Although causes had not been clearly specified, the company in which the accident occurred presented the following two possibilities.
1. Diazodinitrophenol entered into a crack in a splitter plate fixed to the drier of a granulating machine with an adhesive agent. As a result, diazodinitrophenol ignited due to an impact and friction, burned, and detonated.
2. Iron rust contaminated in diazodinitrophenol in the granulating machine, and friction sensitivity increased. Therefore, diazodinitrophenol ignited in the granulating process, burned, and detonated. |
| Countermeasures |
The following were done for preventive measures.
1. In terms of facilities.
(1) Remodeling of the splitter plate in the lower part of the granulating machine. The machine was changed to an integral construction from an attached type so that it would be difficult for powder to get inside, and would be easy to inspect and clean.
(2) The parts of the machine where iron rust might be generated and enter were changed to integral construction with rubber to prevent rust formation and contamination.
(3) A prevention board against foreign materials and contamination was installed, so that foreign materials could not come into contact with explosives.
2. In terms of management.
(1) Daily checks and turnaround checks were improved.
(2) The importance of avoiding invasion of chemicals and foreign materials that might cause ignition and an explosion was reeducated. |
| Knowledge Comment |
1. Ideally, a method of daily checks should be considered and reexamined before an accident occurs.
2. Iron rust was a cause. Air and water exist universally and they are the causes of various problems. In a system where there are concerns about the generation of iron rust, the same care as air and water should be given to iron dust. |
| Background |
This was the first accident experienced at the plant. Therefore, it seems that the company took insufficient care for age degradation. It is reported that iron dust had been a cause of accidents through promoting decomposition in the various processes. Safety management for sensitive materials, such as initiative explosives, seems to have been insufficient as well as countermeasures against age degradation. |
| Reason for Adding to DB |
Example of explosion of an initiative explosive |
| Scenario |
| Primary Scenario
|
Poor Value Perception, Poor Safety Awareness, Overlooking of Secular Degradation, Organizational Problems, Poor Management, Slackness of Management, Carelessness, Insufficient Precaution, Carelessness of Operator, Usage, Maintenance/Repair, Insufficient Inspection, Regular Operation, Erroneous Operation, Overlooking in Daily Operation, Bad Event, Chemical Phenomenon, Heat Generation/Ignition, Secondary Damage, External Damage, Explosion, Loss to Organization, Economic Loss, Resration Fee , etc.
|
|
| Sources |
Ministry of Economy, Trade and Industry. On-the-spot inspection results to prevent recurrence of countermeasures for explosion at AK Co. detonator factory. Press announcement material. (2002)
Kyushu Department of Economy and Industry. On the report of cause and countermeasures, results of on-the-spot inspection and report for improvement performance, etc. Kyushu Department of Economy and Industry announcement material. (2002)
|
| Physical Damage |
A drier was damaged. A wooden door blew off. Several windows were damaged. The ceiling of a room collapsed. |
| Financial Cost |
About ¥ 10 million (by July 13th, newspaper) |
| Multimedia Files |
Fig3.Chemical formula
|
| Field |
Chemicals and Plants
|
| Author |
KOBAYASHI, Mitsuo (Office K)
TAMURA, Masamitsu (Center for Risk Management and Safety Sciences, Yokohama National University)
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