Hazard Alert
Worker's Compensation Board
POSTER # 97-12

Vessel compartments and tanks

Test before welding or cutting

A welder was killed following a violent explosion on an aluminium fish boat. At the time of the accident the welder was welding a seam on the stern flotation compartment that was located next to the vessel's gas tank. The vessel was in a boat builder's shop for renovation and repairs. One of the repairs was to the gas tank that had been leaking. The tank had been removed, and repaired, and was being replaced when the accident happened. Tests, following the accident, found explosive levels of gas vapours in the forward compartments of this vessel. Gasoline from the gas tank had leaked into the compartment below the gas tank and then travelled into all the other compartments. Prior to the welding, there had been no testing done for volatile or flammable substances in any of the boat's compartments.

Safe work practices:

  • Employers, ensure the adequate instruction of workers in the safe performance of their duties.
  • Institute a system of inspection and tests (using proper testing equipment) before any work is undertaken when workers are employed in an area where there is the possibility of the presence of volatile or flammable substances, gases or vapours.
  • Ventilate, purge, clean and re-test before welding any area or space where a harmful atmosphere may exist.
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This poster is part of an archival collection of WCB health and safety posters, dating from 1969 until the present time. At the time this poster was originally produced, it reflected the current WCB requirements. In all cases, today's WCB regulation and requirements must be applied to the situation shown in each poster.