Petrol Spill and a Car on a Trolley Jack
At 10:30 on a Saturday, a two-bay workshop has a four-wheeler petrol tank removed for a fuel-pump replacement. About two litres of petrol have spilled across the concrete floor and are spreading toward a floor drain. An apprentice is using an angle grinder three metres away on a seized exhaust bolt. The car is held up only by a hydraulic trolley jack, with no axle stands; the near-side front wheel is off. A compressor hose lying in the spill is leaking air and a fine oil mist. Two customers are standing inside the bay. The workshop has a dry-powder extinguisher, a CO2 extinguisher, a water hose and a bag of sawdust. The supervisor must decide the immediate sequence of actions and what must be done before anyone restarts work.
1. List the unsafe conditions in the order you would control them, and justify why your first action takes priority.
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The first action is to stop the angle grinder and any other ignition source, because petrol vapour can ignite at a distance and the grinder is the most immediate ignition risk. Next, move the customers out of the bay and ventilate the area. Then isolate the compressor and remove the air/oil mist hazard, because a fine oil mist plus fuel vapour increases the fire risk. Contain the spill with sawdust or an inert absorbent, keeping it away from the floor drain. Only after the fire and slip hazards are controlled should the car be raised on axle stands and the wheels chocked. The trolley jack alone is not a safe support; a hydraulic jack can bleed down. The order is based on severity and immediacy: ignition, then exposure, then environmental spread, then mechanical support.
2. Which extinguisher and spill-control material should be used, and why is the water hose unsuitable for this petrol spill?
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For a petrol fire, use the dry-powder or CO2 extinguisher; dry powder is suitable for flammable liquids, and CO2 is useful on small electrical or liquid fires where a clean agent is needed. For the spill itself, use sawdust or a proprietary absorbent and place it around the spill edge, not in the drain. Water from the hose is unsuitable because petrol floats on water and can spread the burning fuel over a wider area; flowing water can also carry petrol into the floor drain, creating a vapour explosion risk. The water hose should not be used as a substitute for a foam or dry-chemical extinguisher on a fuel fire.
3. What jacking, wheel-chocking and PPE controls must be in place before work resumes?
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The car must be raised at the manufacturer's jacking points and supported on axle stands rated for the load, with the trolley jack left as a secondary support only. The rear wheels must be chocked on both sides, and the handbrake applied. Before anyone goes under the car, lower it slightly onto the stands and check stability. PPE should include nitrile gloves, eye protection and footwear that does not create static sparks; avoid synthetic clothing that can build static near fuel. No mobile phones or naked flames in the bay. Keep the dry-powder extinguisher within reach, and do not restart work until the spill is removed and the area is ventilated.