Carbon monoxide, also known as CO, is called the "Invisible Killer" because it's a colorless, odorless, poisonous gas. More than 150 people in the Unites States die every year from accidental non-fire related CO poisoning associated with consumer products, including generators. Other products include faulty, improperly-used or incorrectly-vented fuel-burning appliances such as furnaces, stoves, water heaters and fireplaces.
If you suspect CO poisoning, get outside to fresh air immediately, and then call 911.
Because CO is odorless, colorless, and otherwise undetectable to the human senses, people may not know that they are being exposed. The initial symptoms of low to moderate CO poisoning are similar to the flu (but without the fever). They include:
High level CO poisoning results in progressively more severe symptoms, including:
Symptom severity is related to both the CO level and the duration of exposure. For slowly developing residential CO problems, occupants and/or physicians can mistake mild to moderate CO poisoning symptoms for the flu, which sometimes results in tragic deaths. For rapidly developing, high level CO exposures (e.g., associated with use of generators in residential spaces), victims can rapidly become mentally confused, and can lose muscle control without having first experienced milder symptoms; they will likely die if not rescued.