| Case Name |
Leakage of fuel oil caused due to damage to a flexible hose at a fuel oil tank piping |
| Pictograph |
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| Date |
March 14, 1989 |
| Place |
Kawasaki, Kanagawa, Japan |
| Location |
Chemical factory |
| Overview |
There was an emergency call to Kawasaki fire fighters. When the fire crew arrived, they found the followings. A flexible hose connected to the valve of a fuel oil tank and fuel oil piping to the boiler of the factory was damaged, and fuel oil had leaked, partly flowed out into the sea. The cause was considered to be as follows: The length of the flexible hose used was too long and the mounting was not correct Therefore, there was a large tensile stress and the flexible hose broke. The cause of the leak into the sea was considered to be a crack at the side ditch in the tank yard. Leaked oil flowed underground and then flowed out into the sea. |
| Incident |
A flexible hose of fuel oil feed piping for a boiler in the tank yard was damaged, and fuel oil leaked. The leaked fuel oil flowed out into a canal. |
| Processing |
Consumption and usage |
| Substance |
Fuel oil |
| Type of Accident |
Leakage, environmental pollution |
| Sequence |
At 21:00 on March 12th, 1989, a steam boiler started up, and feeding of fuel oil started from a fuel oil tank.
On March 13th, the fuel oil tank was switched over.
At 09:00 on March 14th, it was found during patrolling that fuel oil had leaked from the vicinity of a flexible hose of fuel oil piping.
Furthermore, a public fireman found that the fuel oil had escaped into the canal from the drain gate as a result of field investigation. |
| Cause |
1. A connecting method of the flexible hose was not correct. A 1690 mm flexible hose had been installed at 1385 mm of face-to-face dimension of the mounting flange. It had been installed at an angle. Therefore, stresses concentrated at the metal fitting weld, a blade was damaged, shearing stress was generated at bellows, and a crack was generated.
2. It is estimated that the leaked oil oozed out from the crack at a groove in the tank yard, and passed underground through a rain sewer into the canal. |
| Response |
Feeding of fuel oil was stopped. An oil fence was set up in the canal, and the spilled oil was treated with adsorption mats and oil dispersants. |
| Countermeasures |
1. Mounting methods of a flexible hose should be reviewed and the results should be applied to piping around other tanks.
2. The necessary countermeasures should be taken for preventing the outflow of fuel oil from the dike into the canal. |
| Knowledge Comment |
1. There is a Japanese proverb: "The greater serves for the smaller." However, in this case "The greater does not serve for the smaller." Selection of parts that were too big disturbed the balance and led to the failure.
2. One failure does not always lead to an accident. An accident can be prevented if corrective work is carried out appropriately. In this case, even if the piping was completed with incorrect design and construction, the accident could have been avoided by corrective measures if someone had been sufficiently attentive and had correct knowledge about the facilities and operation management. |
| Background |
Two errors seemed to be the causes of the accident: 1) design error in selecting a flexible hose; the length of the hose was not appropriate for face-to-face flange dimensions. 2) An installation error.
There was a fundamental management problem which resulted in no detection of the improper flexible hose at the engineering stage, which led to continuous use of the flexible hose without any perception of hazards.
The error might have been caused due to such a simple task as selecting and mounting a flexible hose when it was left to the individual judgment of a designer or an operator.
The oil leak into the canal was caused due to cracks in a ditch used for piping and remained after the piping was removed. The floor in the dike was paved with concrete. It is considered that the cracks were overlooked or not repaired. This might be caused due to either insufficient skills of the operation staff or an organizational problem. |
| Incidental Discussion |
In the "background" column, it is indicated that the crack in the ditch was overlooked due to organizational problems or insufficient operator's skills. In fact, it would have been very difficult to find a crack in the ditch of the tank yard at a glance. In the good weather a crack cannot be discovered from a leak. For finding the crack, it is necessary to check the water depth carefully in the ditch many times in the rainy weather, when water accumulates..
There is also no legal requirement to concrete the area in the dike of the dangerous material tank. In this case, oil leaked from the crack and flowed underground through a buried structure. However, a buried structure is not usually constructed in the dike. |
| Reason for Adding to DB |
Example of accident caused due to lack of improvement as a result of overlooking mistakes |
| Scenario |
| Primary Scenario
|
Organizational Problems, Inflexible Management Structure, Insufficient Education/Training, Ignorance, Insufficient Knowledge, Insufficient Study and Experience, Poor Value Perception, Poor Safety Awareness, Inadequate Risk Recognition, Planning and Design, Poor Planning, Poor Design, Failure, Fracture/Damage, Crack, Secondary Damage, External Damage, Leakage, Secondary Damage, Damage to Environment, Sea Pollution
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| Sources |
Kawasaki City. Fire fighting station. Prevention division. Peace section. Outline of fuel oil spill incident at dangerous material outdoor tank area, N Co. K factory. Material of the Kawasaki City Complex safety countermeasure committee.
|
| Physical Damage |
A flexible hose was damaged. |
| Financial Cost |
¥180,000 (Material of the Kawasaki City complex safety countermeasure committee) |
| Consequences |
Fuel oil escaped into a canal. |
| 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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