| Case Name |
Leakage of varnish for ink after transfer to a fully occupied tank where an alarm lamp lit |
| Pictograph |
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| Date |
April 28, 1994 |
| Place |
Kawasaki, Kanagawa, Japan |
| Location |
Chemical factory |
| Overview |
At a factory producing varnish for newspaper ink, the control room operator directed transfer of the varnish to a tank where a high level alarm lamp was lit, and the operator confirmed it. The manufacturing operator started transferring without confirming the tank level. Therefore, the varnish overflowed, and some varnish leaked into a canal. |
| Incident |
At a manufacturer of ink for newspapers, the raw material varnish for newspaper ink was refined by centrifugation and transferred to a purified varnish tank. Purified varnish leaked from the clearance of the upper manhole of the tank installed at the building's second floor. In addition, varnish spouted out from a vent pipe tip on the manufacturer's roof. The varnish that had spouted from the vent pipe passed through a rain gutter and rain water piping from the roof, and leaked into a canal. |
| Processing |
Manufacture |
| Individual Process |
Transfer |
| Process Flow |
Fig2.Process flow
|
| Substance |
Varnish |
| Type of Accident |
Leakage, environmental pollution |
| Sequence |
At about 16:00 on April 27th, 1994, an alarm in the control room of tank VT-7 rang, and the alarm light indicating full occupation lit. The volume in the tank was confirmed by opening the manhole of the tank. It was judged that receiving was possible, the alarm buzzer was stopped, and receiving continued.
At about 16:30, acceptance in the tank VT-7 was completed, the volume in the tank was 3850 L. The maximum control volume of the tank was usually 3800 L, and the legal capacity was 4300 L..
At about 09:30 on 28th, a varnish manufacturing operator was directed to transfer other purified varnish to tank VT-7 by the control room. The operator did not confirm the volume of VT-7 at this time. However, meantime, the control room operator who directed the transfer confirmed that the alarm lamp indicated full occupation lit.
At about 10:20, transfer to tank VT-7 was started.
At about 11:15, the manufacturing operator found varnish overflowing from tank VT-7. The transfer was stopped immediately. He reported to the control room.
At about 11:20, it was found that the varnish had leaked from the vent pipe on the roof. |
| Cause |
The control room directed the transfer of varnish to the tank in spite of the alarm lamp indicating fullness of the tank lit. The manufacturing operator transferred the varnish to the tank without confirming the tank level, and varnish overflowed. |
| Response |
The transfer was stopped, and company employees cleaned all over the factory and ladled out residual varnish from a rainwater sewer. To treat the varnish flowed out into the sea, marine services were called out, and a neutralizer was scattered. In addition, an oil fence was set up at the scupper exit of the factory. |
| Countermeasures |
1. The operational control method was changed. The process control room and varnish manufacturing operators have a meeting before work every morning, and confirm not only the work schedule but also the tank level, piping, and equipment by visual observation.
2. A spill incident committee was set up. Employees were re-trained to prevent the occurrence of a similar accident.
3. The facilities were remodeled. A transfer pump is stopped by an interlock when the tank level reaches a high level. |
| Knowledge Comment |
1. A double check should have been carried out before starting transfer, with confirmation of the tank at the site by a manufacturing operator and confirmation in the control room by a control staff. However, the workers did not carry out their duties. A double check would be a mere fantasy if each individual does not carry out his/her responsibilities.
2. The accident might be caused when prevention methods depend on only human attention. The countermeasures should also be considered in instrumentation and mechanical aspects. |
| Background |
As a human factor, it is considered that the operation manual was not observed. The behavior of a control room operator and a manufacturing operator on the day indicates that. Orders were not obeyed, either. It is supposed that some similar permission had been given before, because permission to transfer varnish was given even when the lamp indicated full occupation lit. It can also be thought that there were insufficient education and training on alarm meanings and countermeasures.
As for the facilities aspect, the tank level alarm was the only equipment showing the level of the tank, and there were no other appropriate level management or overflow prevention facilities. |
| Incidental Discussion |
It is a typical and classic accident. Even if the double check is made, it has no meaning when each individual acts without a sense of responsibility. |
| Reason for Adding to DB |
Example of importance of confirming procedure at start-up |
| Scenario |
| Primary Scenario
|
Organizational Problems, Inflexible Management Structure, Insufficient Information Transfer, Poor Value Perception, Poor Safety Awareness, Inadequate Risk Recognition, Carelessness, Insufficient Precaution, Inadequate Handling, Malicious Act, Rule Violation, Safety Rule Violation, Planning and Design, Poor Planning, Poor Design, Secondary Damage, External Damage, Leakage, Secondary Damage, Damage to Environment, Sea Pollution
|
|
| Sources |
Kawasaki City, Fire fighting station, Prevension division, Peace section. N ink Co., Ltd. Varnish leakage incident in the manufacture of dangerous material. Material of the Kawasaki City complex safety countermeasure committee.
|
| Financial Cost |
About ¥10,000. (Material of the Kawasaki City Complex safety countermeasure committee) |
| Consequences |
About 50 liters of varnish leaked 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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