Hot Work Beside an Open Thinner Drum
At 16:30 in a small body shop, a technician is asked to MIG-weld a replacement patch into the left rear quarter panel of a van that must be collected by 07:00. The welding bay extraction unit has failed and the only respiratory protection within reach is a disposable P2 dust mask. A 20-litre drum of thinner has been left open about 3 metres from the work area, the floor is still wet with degreaser, and the CO2 extinguisher is in the front office. There is no fire blanket or welding screen. A second technician is sanding a door 4 metres away, and the supervisor says the job cannot wait for the extractor to be repaired. The workshop has no hot-work permit system and no gas detector on site. The technician has a fixed-shade welding helmet, leather gloves and overalls, but the overalls have an oil patch on the left thigh.
1. Identify the immediate hazards and state whether the technician should start welding. Justify the decision.
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The technician should not start. The open thinner drum is the most serious hazard: solvent vapour is heavier than air, can travel along the floor and can be ignited by welding sparks or hot slag several metres away. The wet degreaser adds another flammable vapour source, and the oil patch on the overalls can catch fire. The P2 dust mask does not protect against organic vapour or welding fume, and the failed extraction means fume will accumulate in the breathing zone. The CO2 extinguisher is not immediately available, there is no fire blanket or screen, and the second technician is exposed to arc radiation and sparks. The supervisor's deadline does not remove the employer's duty to provide a safe system of work. The correct judgement is to stop, isolate the area, remove or close the ignition sources and request a properly controlled hot-work setup before any arc is struck.
2. Apply the hierarchy of control and list the actions required before hot work can proceed.
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First eliminate or postpone the hot work if the patch can be fitted by another approved method; if welding is essential, move the job to a designated hot-work bay or outdoors away from flammables. Close and remove the thinner drum to a flammable store, clean the degreaser from the floor, and clear combustible material within at least 10 metres. Repair or substitute the extraction unit, or use a portable fume extractor at the arc; general ventilation alone is not enough. Issue a hot-work permit, test the atmosphere with a calibrated gas detector where flammable vapour may be present, and appoint a fire watch with a suitable extinguisher and fire blanket. Provide a welding screen to protect the second technician. Replace the P2 mask with appropriate respiratory protection for welding fume, and change the oil-contaminated overalls. Check that the welding set is earthed and cables are undamaged. Only after these controls are in place should welding be considered.
3. What should be recorded and communicated to the supervisor and workshop owner?
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The technician should record the refusal or postponement in the job card and in the workshop safety log, noting the date, time, location, the failed extraction, the open thinner drum, the inadequate mask, the missing fire equipment and the supervisor's instruction. The record should state the controls required before work resumes and who is responsible for them. The supervisor and owner should be told verbally and in writing that the job cannot safely proceed as set up, and that the delivery date must be renegotiated. This is not a personal complaint but a formal hazard report. If the owner insists on proceeding, the technician should escalate through the safety representative or regulator rather than rely on informal warnings. Photographs of the area help, but they must not replace the written record. The aim is to protect the technician, the second technician and the customer's vehicle from a foreseeable fire or fume incident.