05 September 2007

Carbon Dioxide Asphyxiation

Safety Incident Topic: Carbon Dioxide Asphyxiation Due To Exposure To Carbon Dioxide
Location of Incident: 33kV Switchgear Room, Malaysia
Date of Incident: 17 April, 2007

Brief Account of Incident
A contractor personnel was unconscious due to asphyxiation when a CO2 fire protection system activated inside an electrical switchgear room. The incident occurred during functional testing of a fixed CO2 fire protection system, which had earlier been relocated and isolated, when another CO2 system inside the same area activated. The victim was evacuated from the room by the plant’s emergency response team and regained consciousness after given first-aid treatment.

1. One contractor personnel was asphyxiated due to CO2 exposure
2. The entire fixed CO2 fire protection system for the 33kV switchgear room was out of service due to loss of CO2 from the cylinders bank.

Active Failures
Unauthorized testing of the CO2 fire protection system by an incompetent personnel.

Lesson Learned
1- All work including functional testing of electrical/instrument system should be approved by authorized personnel of the OPUs. The work should be supervised and performed by competent personnel.
2- The effect of a stop-work-order should be made understood to all personnel and necessary actions e.g. cancellation/withdrawal of PTW, evacuation of personnel from the work area etc. should be taken as soon as possible.
3- Relevant parties such as Operation, Maintenance Project Team and HSE etc. should be involved in the review of method statements, Job Safety Analysis and other work procedures to ensure all hazards are identified and control measures e.g. isolation requirements are taken.
4- Method statement for each task should be documented in detail e.g. the steps to be taken, the specific switch(es) to be isolated etc. The method statement should be discussed with all relevant parties involved including the contractor and subcontractors prior to the job.
5- Access into rooms which are protected by fixed fire protection systems e.g. CO2, FM200 etc should be controlled especially during testing of the system.6- Updated drawings to be made available in the plant.

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