In October 2017, a maintenance technician escaped serious injury when an explosion happened while he was performing a valve adjustment on a dump truck.
A 12 volt LED lamp with a magnetic base was used to illuminate the work area. The technician used a brake cleaning solvent to clean up the task area, and the solvent vapours (heavier than air) built up within the confines of the engine and accumulated in the sump. The lamp was accidentally dislodged and fell, causing a spark that ignited the vapours and resulted in an explosion.
The cast iron sump disintegrated as a result of the explosion and the technician received burns to his face.
Direct causes
- Flammable solvent vapours built up in the engine and were ignited by a 12 volt LED lamp connected directly to the truck battery.
Contributory causes
- Inadequately identifying the hazards associated with the use of the particular cleaning product in the site’s risk assessment:
- flammable properties of the vapours released by the brake cleaner solvent were not identified
- the solvent was branded as a brake and parts cleaner and degreaser, and was considered by the site as a general use item
- the application of cleaning solvents with this task had not been identified in the site's safe work instructions or in the original equipment manufacturer’s (OEM’s) maintenance specifications.
- Failure to follow safety instructions provided by the solvent manufacturer on the SDS.
- Failure to ensure adequate ventilation of the work area.
- Failure to use electrical equipment suitable for a flammable environment.