Construction Safety Association of Ontario
Hazard Summary: A worker at a large, enclosed construction site died of carbon monoxide poisoning after he and six other workers were exposed to high levels of the gas. Ventilation on the site was inadequate, and three machines were giving off carbon monoxide: a portable mixer and a trowel, both powered by gasoline, and a forklift powered by propane. Description and Health Effects Carbon monoxide is often called "the silent killer ,"because it gives no clear warning to its victims. It is an invisible gas with no taste or smell and it will not cause any unusual feeling in the nose, mouth or throat as it is breathed in. The first effects that can actually be noticed are headache and faintness. A worker who does not know about carbon monoxide poisoning may ignore these early symptoms or think a minor illness is coming on. But continuing exposure can cause confusion, loss of consciousness, and even death. Unless workers know about the dangers of carbon monoxide, they may never even think about moving away from air that is poisoning them. Sources and Patterns of Spread All fuel-burning equipment emits some carbon monoxide. This includes car, truck and forklift engines, construction equipment powered by propane or gasoline, and non-electric heaters. Poorly maintained equipment usually emits more carbon monoxide: a poorly tuned gas engine may give off up to 12 times as much carbon monoxide as a well tuned one. Carbon monoxide tends to build up in pockets in the poorly ventilated areas of workplaces. This can happen even in semi-enclosed workplaces,where tarpaulins and plastic sheeting are used for shelter. Recommended Precautions:
Measuring Exposure: Equipment:
Time-Weighted Average Exposure Value (TWAEV):
Short-term Exposure Value (STEV):
Immediately Dangerous To Life and Health (IDLH):
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