The incident

As a precaution, electrical heaters were switched off and protected from the cleaning water by tarpaulins.

The next area to be cleaned was being inspected by the cleaning supervisor and electrician on watch to ensure precautions were in place (e.g. electrical heaters switched-off and protected from washing water etc).

During this inspection, the cleaning supervisor informed the electrician on watch that the washing of the first area was complete.

Upon completion of the inspection of the next area, the electrician remotely switched on the heater in the first area to assist with drying.

However, whilst washing activity in the first area was complete, the housekeeping was not.

There were still three portable lights on top of the heater and it was still covered by tarpaulin.

The three portable lights, tarpaulin and some adjacent electrical cables all caught fire.


Probable causes

  • When the cleaning supervisor informed the electrician that the washing of the column was finished, the electrician assumed that this included housekeeping;
  • The electrician switched on power to the heater without physically verifying that the protection had been removed.



  • Check. Always physically verify that worksites are returned to a safe condition after completion of work;
  • Never assume that the site is safe without making sure;
  • Never re-energise equipment before making sure that it is safe to do so.


In 2018, IMCA published 29 Safety Flashes covering a total of 136 incidents, sharing lessons learned to improve safety performance in the industry.