The Full form of CO is Carbon Monoxide. It is a colorless, odorless, and tasteless flammable gas that is slightly less dense than air. It is a toxic gas to animals that use hemoglobin as an oxygen carrier (both vertebrate and invertebrate) when encountered in concentrations above about 35 ppm, although it is also produced in low quantities in normal animal metabolism, and is considered to have some normal biological functions.

In the atmosphere, it is short lived and spatially variable, having a role in the formation of ground-level ozone. Carbon Monoxide (CO) gas is produced by burning propane, wood, gasoline, charcoal or other fuel. Improperly ventilated engines and appliances, particularly in an enclosed or tightly sealed space, may allow CO to accumulate to dangerous levels. Carbon Monoxide poisoning is caused due to building of carbon monoxide in a human bloodstream.

When there is too much Carbon Monoxide in the air, the human body replaces the oxygen in the RBCs (red blood cells) with Carbon Monoxide. This can even lead to serious tissue damage, or death. Carbon Monoxide (CO) poisoning can be very dangerous for people who are intoxicated or sleeping. There are some signs and symptoms of Carbon Monoxide poisoning that may include: Weakness, Dizziness, Nausea or vomiting, Dull headache, Shortness of breath, Confusion, Loss of consciousness, blurred vision, etc.