Carbon monoxide (CO) is a product of incomplete or poor combustion. It's a direct and cumulative poison. Many people encounter CO regularly and never know it because it's invisible and odorless. Unless the building has a CO alarm, victims of CO poisoning often have no warning that they are in danger until it's too late. CO replaces oxygen in the blood until it completely overcomes the body. Death from CO can occur suddenly. Symptoms can include headache, nausea, chronic fatigue, flu-like symptoms, fever, confusion and dizziness.

Tip: Company officers must recognize the hidden dangers of carbon monoxide exposure and ensure that crews operate safely on those incidents, which include the performance of overhaul operations after a fire. All personnel operating in the hazardous area must wear full personal protective equipment including SCBA. The compartment or area must be evaluated continuously using atmospheric monitoring equipment, reporting all readings to command. Proper ventilation should be completed as soon as possible, using either natural or mechanical ventilation.