Materials that do not burn in normal atmospheres will ignite more readily, burn at higher flame temperatures and burn more rapidly in oxygen-enriched atmospheres. Leaks or improper handling may result in exposure of unintended materials to oxygen. Leaks or spills of liquid oxygen could result in rapid oxygen enrichment as it is denser than gaseous oxygen. Clothing, materials and skin may be rendered ignitable and flammable on exposure to oxygen.
Liquid oxygen is extremely cold and frostbite may occur from contact with liquid oxygen. Oxygen toxicity may result from breathing high concentration of oxygen. Long hours of breathing 60 percent oxygen could result in low-pressure oxygen poisoning. Exposure to increased pressure during driving or hyperbaric chamber operations may increase the symptoms. Symptoms could escalate from burning sensation to coughing or pain and may result in permanent lung damage or pneumonia. Exposure to 1.6 atmospheres of oxygen may result in high-pressure oxygen poisoning or central nervous system toxicity exacerbating to violent convulsions or unconsciousness.
Flying debris can result from oxygen stored under pressure. Vessels used to store liquid or gaseous oxygen could become flammable from increase in oxygen concentration. For example, if the temperature of oxygen increases to 155 degrees K, it cannot be kept as a liquid. Liquid oxygen continually boils to gas even in well insulated cryogenic containers. The risk of overpressure can be minimized by well designed pressure relief for such closed containers. The mechanical and thermal properties of materials associated with gaseous or liquid oxygen must be well designed to avoid component failure.
Gases and liquids soluble or miscible in oxygen may give rise to health hazards. Nitrogen can displace oxygen causing asphyxiation, for example, and mixing of flammable gases can result in flammable atmospheres. Low temperatures of oxygen can cause condensation or solidification of impurities, giving rise to unsafe levels of contaminants.