Carbon Monoxide (CO)

Carbon Monoxide (CO) is a poisonous, colorless, odorless, and tasteless gas. CO is a common industrial hazard resulting from the incomplete burning of natural gas and any other material containing carbon—such as gasoline, kerosene, oil, propane, coal, or wood. Forges, blast furnaces, and coke ovens produce CO, but one of the most common sources of exposure in the workplace is the internal combustion engine, often in appliances or vehicles.  The OSHA Permissible Exposure Limit (PEL) for CO is 50 parts per million (ppm) as an 8-hour time-weighted average (TWA).

When not properly ventilated, emitted CO can build up. Carbon monoxide is harmful when breathed because it displaces oxygen in the blood and deprives the heart, brain, and other vital organs of oxygen. Employees exposed to low levels of CO may feel sick with headache and nausea, and will feel better when exposed to fresh air outside. However, their symptoms will recur shortly after returning to their workplaces if CO is not eliminated. Large amounts of CO can overcome workers in minutes without warning, causing them to lose consciousness and suffocate.

Workers who may particularly be at risk of a CO hazard are those who work in boiler rooms, breweries, warehouses, and petroleum refineries; in pulp, paper, and steel production; around docks, blast furnaces, or coke ovens; or in one of the following occupations:

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