Nitrous oxide
Nitrous oxide is a significant occupational hazard for surgeons, dentists and nurses. Because nitrous oxide is minimally metabolised in humans (with a rate of 0.004%), it retains its potency when exhaled into the room by the patient, and can pose an intoxicating and prolonged exposure hazard to the clinic staff if the room is poorly ventilated. Where nitrous oxide is administered, a continuous-flow fresh-air ventilation system or scavenger system is used to prevent a waste-gas buildup.