| Case Name |
Large explosion caused due to a spill of liquefied propane from an over filled cylinder at a LP gas filling station |
| Pictograph |
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| Date |
May 17, 1986 |
| Place |
Yokkaichi, Mie, Japan |
| Location |
LPG filling station |
| Overview |
On May 17th, 1986. There was overfilling of a LP gas cylinder in a LP gas filling station. To decrease the filled weight, a worker pushed the cylinder down sideways and opened the valve to release liquefied propane into atmosphere. As the discharged gas ignited, he evacuated in a hurry without closing the valve. The gas ignited and heated the cylinders filled with LP gas, resulting in a large explosion. It became catastrophic. The handling errors, such as over-filling by carelessness and poor treating of over-filled gas, etc were the direct causes. The basic cause was a management system that allowed the absence of a person in charge of safety on the day and miss-handling in the past. |
| Incident |
A large explosion occurred at a LPG filling station. In the filling process, a cylinder was over-filled beyond the regulated limit weight of 20 kg. To decrease the filled weight, a worker pushed the cylinder down sideways and opened the valve to release liquefied propane onto the concrete floor. The released gas suddenly ignited, the worker panicked and evacuated. As the valve could not be closed, the spouting gas kept burning. By heating other filled cylinders, the fire became very large with sequential ruptures and ignitions of cylinders. Two workers received severe burns, more than 100 cylinders were destroyed, and nine buildings and 23 automobiles were destroyed by fire. One fireman was injured. |
| Processing |
Manufacture |
| Individual Process |
Filling and Subdivision |
| Substance |
LPG (Liquefied petroleum gas) |
| Type of Accident |
Explosion, fire |
| Sequence |
On May 17th, 1986: Three workers were in the cylinder filling room. One worker started the filling work at No.1 filling machine after setting a 20kg cylinder. Then he also set a 50kg cylinder at No.2 filling machine. When he saw the No.1 machine just near the No.2 machine, he found that a 20kg cylinder was miss-set in the No.1 filling machine.
He detached the cylinder and checked it, finding it was over-filled. To decrease the filled weight, the worker pushed the cylinder down sideways and opened the valve to release the liquefied propane onto the concrete floor. The released gas ignited within a few seconds.
About 13:30. A fire occurred.
About 13:32. 119 calls were made.
About 13:35. Cylinders were ruptured.
About 13:37. Fire engines arrived.
About 13:42. The force of fire increased, and it spread.
About 13:45. There were numerous explosions and debris from ruptured containers was scattered.
About 14:00. The force of fire weakened.
About 15:10. The fire was extinguished except for combustion flames of the gas from the gas vent piping of the tank. |
| Cause |
1. Over-filling caused due to carelessness.
2. A handling error on treating over-filled cylinder.
Ignition cause was considered to be static electricity. |
| Countermeasures |
1. Improvement in safety management. (Thorough management and enforcement of security inspection, etc.)
2. The prevention of the over filling. (Improvement of the filling machine and awakening attention)
3. Improvement in the way of treating over filled gas. (A recovery system).
4. Taking countermeasures to prevent an accident from expanding. (Shutdown facilities, a gas detector, water sprinkling facilities). |
| Knowledge Comment |
An elementary error in the handling of high-pressure gas and combustible gas was the direct cause of the accident, and appropriate education and guidance for employees are important. Also, we should learn that accident damage was aggravated by the poor safety management system. |
| Background |
The manager is responsible for a lack of safety education of the workers who handle LPG.
There was a problem in the security system as the staff in charge of safety was absent on the day of the accident.
In addition, there seems to have been a lack of safety consciousness, such as miss-operation (release of gas) had been performed more than 10 times.
Although it is not taken up in the report, simultaneous parallel work might be also a problem. There are many examples of failures during simultaneous parallel work. |
| Incidental Discussion |
The volume of combustion gas is about 10000 times larger than that of leaked hydrocarbon liquid. It has to be sufficiently understood that a slight leakage generates a very large amount of combustion gas. |
| Reason for Adding to DB |
Example of explosion due to an handling error of a high-pressure cylinder with combustible gas |
| Scenario |
| Primary Scenario
|
Organizational Problems, Inflexible Management Structure, Insufficient Education/Training, Carelessness, Insufficient Understanding, Insufficient Recognition of Risk, Planning and Design, Poor Planning, Poor Design, Malicious Act, Rule Violation, Safety Rule Violation, Secondary Damage, External Damage, Fire, Bodily Harm, Injury, 2 person injured, Loss to Organization, Economic Loss, LPG Filling Statuion Heavily Damaged, Damage to Society, Social Systems Failure, 9 adjacent buildings burnt
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| Sources |
High Pressure Gas Safety Inst. of Japan. Outline of Yokkaichi LP gas filling station explosion, and related problems. 1986.
Filling station explosion when gas release was from overfilled cylinder. May 1986 Mie Prefecture, Major accidents in the twentieth century showing on photographs. Safety Engineering No.114, pp.18-19(2001)
Japan Soc. for Safety Engineering. Liquid release of LP gas is very dangerous. Basics of accident prevention. pp.1-2(1991).
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| Number of Injuries |
3 |
| Physical Damage |
A LPG filling station including an office and a warehouse was destroyed by fire. Twenty-five cylinders of 500 kg LPG, 441cylinders of 50 kg LPG and other containers were destroyed by fire. A tank lorry and trucks, etc. at the gas station inside the site were damaged by fire. |
| Consequences |
About 2km of the traffic on the national road No.1 stopped until the next morning. |
| 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)
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