Oxygen (thing)

{medical} Humans need oxygen to survive and take it from the air through the lungs by breathing. Without oxygen the brain can die from anoxia or hypoxia in less than five minutes, with permanent brain damage possible in less than three minutes. An injured person is often given pure oxygen by EMTs and/or paramedics or by a physician in the hospital emergency room. This is to increase the amount of oxygen reaching the brain and other body parts, helping to stave off shock. Medical oxygen is typically found in green canisters with clear plastic tubing attached, and is given to a patient through either a mask or nasal cannulae. The latter is popular in television and movie portrayals of oxygen administration because it allows the actor / patient to speak and act dramatic, but much less effective for the patient.

{fire science} Oxygen is necessary to the basic chemical reaction known as fire. Fire can be put out by depriving it of oxygen, or caused to grow by giving it more oxygen. Oxygen is thus one leg of the fire triangle. Firefighters deprive a fire of oxygen by smothering it with water, sand, foam or some other material. This is one way that water puts out fires; the other is by heat absorption. Oxygen canisters and tents (used medically as above) are a serious fire hazard, which is why smoking is prohibited near them.