injuries and poisoning
Gas Toxicity During Diving
Nitrogen Narcosis During Diving
Nitrogen narcosis (rapture of the deep) is caused by high partial pressures of nitrogen. Symptoms resemble those of alcohol intoxication. People show very poor judgment and become disoriented and often euphoric. They may fail to surface on time or even swim deeper, thinking they are going to the surface. This effect becomes noticeable at 100 feet (about 30 meters) in some divers breathing compressed air and is usually incapacitating at 300 feet (about 90 meters). To minimize these effects, divers who must dive to great depths typically breathe a special mixture of gases rather than regular air. Low concentrations of oxygen are used, diluted with helium rather than nitrogen, because helium does not cause narcosis. However, diving with helium at depths greater than 500 to 600 feet can precipitate the High-Pressure Neurologic (Nervous System) Syndrome . This resolves during ascent, which must occur at an appropriately slow rate to avoid 