Liquid oxygen can cause explosions when spilled on asphalt or other surfaces, such as bitumastic paving, that are combustible. Occupational safety and health administration (OSHA) regulations require that noncombustible surfacing be provided for "at least 3 feet from points at ground level upon which any leakage of liquid oxygen might fall during operation of the system and filling of a storage container."
Liquid oxygen exists at minus 190 degrees Celsius, a temperature colder than Antarctica. It also is concentrated 860 times. This means it can expand to 860 times its cold volume. These two features of liquid oxygen make it dangerous. For example, in contact with human tissue, it causes severe burns. The extreme low temperature makes materials in contact with it so brittle that they shatter. Fires and explosions can result in air from evaporation of liquid oxygen. For example, cars running over spilled liquid oxygen have been known to explode.
Toxicity problems arise when you breathe in too much oxygen at pressures much higher than atmospheric pressure. Oxygen toxicity occurs often with scuba divers and those on high concentrations of additional oxygen, for example, premature babies. The liquid oxygen on releasing the pressure expands and evaporates prior to use. Symptoms of toxicity include breathing problems, visual recognition problems and even disorientation.
Oxygen is stored in portable cylinders and fixed tanks. OSHA has issued regulations for oxygen storage to minimize the dangers in storage. These storage regulations anticipate the dangers of liquid oxygen and include preventive procedures. For example, OSHA regulations 1910.104 covers storage of bulk oxygen systems, their recommended location, accessibility, leakage problems, elevation and ventilation. Other issues treated are congested areas and noncombustible foundations and supports.