Angle Grinder Disc Burst
A worker is cutting 20 mm rebar with a 230 mm angle grinder on the ground floor of a building. To reach a recess, he has removed the guard. The disc fitted is a 230 mm abrasive disc marked 6,600 rpm; the grinder nameplate says 8,500 rpm. He wears safety glasses, cotton gloves and a dust mask, but no face shield or hearing protection. The extension lead has a nick in the outer sheath exposing inner wires, and the plug is connected to a socket with no RCD. Sparks are landing near two 20-litre solvent drums 3 m away. A second worker is holding the rebar with a gloved hand. The disc shatters; a fragment cuts the worker's forearm and he is bleeding heavily. The second worker runs to get help.
1. What immediate first aid and scene control should be carried out?
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Stop the grinder, isolate the power at the plug, and put on gloves if available. Apply firm direct pressure to the forearm with a sterile dressing or clean cloth; elevate the arm; keep the worker lying down and warm. Call the site first aider and emergency services if bleeding is heavy or spurting. Do not remove an embedded fragment. Keep bystanders back and do not move the damaged lead or drums. Once the casualty is cared for, barricade the area, preserve the grinder, disc and lead for investigation, and report the accident.
2. What should the worker and supervisor have checked before the cut, and what controls were missing?
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Before use: check the guard is fitted and adjusted; the disc is rated at or above the grinder speed - a 6,600 rpm disc on an 8,500 rpm grinder is a burst risk; the disc is correct for metal; the lead and plug are undamaged; the socket is RCD-protected and tested; the work is secured; the area is clear of flammable solvent drums; and the operator is trained. PPE should include a face shield over safety glasses, hearing protection, and close-fitting gloves; loose cotton gloves can catch. Use a hot work permit and a fire watch if sparks are produced near combustibles. The second worker should hold the rebar with a clamp, not by hand.
3. Which failures belong to the worker and which to management, and how should they be corrected?
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Worker-level failures: removed the guard, used the wrong disc, worked with a damaged lead and no face shield. Management failures: no RCD, no inspection and maintenance of leads, no supervision, solvent drums stored in the work area, no hot work permit, no training on disc speed. Correct by replacing damaged leads, testing RCDs, providing guarded grinders and correct discs, training and supervising, relocating flammables, enforcing PPE, and addressing unsafe acts. The aim is to fix the system, not just blame the worker.