During winter, carbon monoxide (CO) poisoning is more prevalent than at any other time of the year. CO is found in many businesses, and workers can be exposed to it by industrial and chemical processes that lack proper ventilation.

Symptoms of exposure include headache, fatigue, lightheadedness, shortness of breath, nausea and dizziness. High concentrations cause unconsciousness, coma and death. Concentration, length of exposure and rate of breathing determine amount of poisoning. Fifty parts per million (ppm) is the permissible OSHA 8-hour time-weighted average; the NIOSH recommended exposure level is 35 ppm.

The chief cause of exposure is exhaust from combustion engines. Propane-powered forklifts, and cars and trucks idling in unvented areas are likely causes. Proper ventilation and exhaust systems must be provided in such locations.

Unvented heating appliances and even outdoor exposure from improperly exhausted equipment have caused CO poisoning. All portable heaters should be operated according to manufacturer’s specifications, with appropriate ventilation provided.

Gasoline-fueled electrical generators, diesel-powered equipment and similar machines have sickened workers. Generators should be placed outside away from windows or air intakes.