Hazards of Liquid Oxygen

Liquid oxygen is very pale blue and somewhat less viscous than water. Since the boiling point of liquid oxygen is -297° at standard atmospheric conditions, it is constantly evaporating into gaseous oxygen which is colorless and odorless.

Pure oxygen, either in a liquid or gaseous state, does not burn or explode. However, liquid oxygen, when mixed with organic liquids, creates a very sensitive high explosive. Gaseous oxygen will support combustion in a violent manner.

Liquid oxygen is extremely dangerous when spilled in a confined area; the gaseous oxygen produced may remain in relatively high concentration while flowing considerable distances. If an oxygen-fed fire occurs, the only positive way of stopping it is by shutting off the oxygen supply. If this is impossible, large quantities of water may cool the flame enough to extinguish it.

Liquid oxygen mixed with grease, oils, petroleum-derivative fuels, or alcohol, forms a highly impact-sensitive gel which is about equivalent to nitroglycerin in explosive energy. This gel, when formed, has the appearance of a dirty white slush and may be detonated by a spark or flame as well as a mechanical shock. It is, therefore, imperative that a gel, if accidentally formed, should not be disturbed and the area should be evacuated until the liquid oxygen evaporates.

The only physiological hazard to be considered in handling liquid oxygen is the effect of the extreme cold, which destroys living tissue and produces an injury similar to a burn. In addition, freezing can restrict blood circulation and cause gangrene, especially in the extremities. Sufficient liquid oxygen splashed into the eyes will cause blindness.

Gaseous oxygen is not toxic, and inhalation has an exhilarating effect.