You cannot see, smell, or taste carbon monoxide, which is a poisonous gas. When carbon monoxide (CO) enters the bloodstream, it reduces the amount of oxygen received by the body’s organs and tissues. Unborn babies, children, the elderly, and people with respiratory problems or heart disease are especially sensitive to carbon monoxide. Even at low levels, carbon monoxide causes serious health problems, and the longer the exposure, the more damage that occurs.
Low levels of carbon monoxide can cause flu-like symptoms, headaches, dizziness, and make it difficult to think clearly. Often a family may not realize that their illnesses are related to chronic exposure to carbon monoxide in the home.

At higher levels of exposure, carbon monoxide is related to visual impairment, reduced work capacity, poor learning ability, and difficulty in performing complex tasks. At very high levels, carbon monoxide can also kill. Each year, more than 200 Americans accidentally die from carbon monoxide poisoning in the home, unrelated to fires and engine exhaust (other sources of carbon monoxide poisoning). Seventy-six percent of these deaths are from carbon monoxide released from heating systems. Another eight percent are from gas water heaters. Many victims of carbon monoxide poisoning die in their sleep. An additional 10,200 people visit the emergency room due to accidental carbon monoxide poisoning from consumer products.