Carbon monoxide (CO) is a poisonous, colorless, odorless and tasteless gas. Although it has no detectable odor, CO is often mixed with other gases that do have an odor. You can inhale carbon monoxide right along with gases that you can smell and not even know that CO is present.
Employees may be exposed to harmful levels of CO in boiler rooms, breweries, warehouses, petroleum refineries, pulp and paper production, and steel production; around docks, blast furnaces, etc., or in one of the following occupations: welder, garage mechanic, organic chemical synthesizer, metal oxide reducer, diesel engine operator, forklift operator to name a few.
If an employee suspects CO poisoning, promptly taking action can save lives: move victim to fresh air in an open area, call 911, administer 100% oxygen using a tight-fitting mask if the victim is breathing, if the victim is not breathing, begin CPR. Caution should be used as the rescuer could be exposed to fatal levels of CO during the rescue attempt.
Initial symptoms of CO poisoning are tightness across the chest, headache, fatigue, dizziness, drowsiness, or nausea. During high or prolonged exposure, the above symptoms will worsen and include vomiting and loss of consciousness and muscle weakness.
Employees should also be encouraged to have a CO monitor with an alarm on each level of their home to protect themselves and their families. These units can be purchased inexpensively at most big box and hardware stores. CO monitors make great safety prizes for events in the workplace.
See https://search.usa.gov/search?affiliate=usdoloshapublicwebsite&query=carbon+monoxide for more information.