Designers of cryogenic liquid hydrogen storage and supply systems should be familiar with all the hazards of gaseous hydrogen as well as those of liquid hydrogen. Additional safety considerations for the use of cryogenic liquid are listed below.
- Due to its extremely low boiling point, liquid hydrogen can cause serious frostbite and hypothermia.
- Ice formation on vents and valves could cause them to malfunction.
- Condensed air could result in oxygen enrichment and explosive conditions near a liquid hydrogen storage system.
- Accidental air leakage into a liquid hydrogen storage vessel (e.g., from inadequate purging) will result in the introduction of moisture. The water will form ice, which may plug lines or cause instruments to malfunction.
- Continuous evaporation generates gaseous hydrogen and an increase in pressure inside a liquid hydrogen storage vessel if not properly released.
- If a liquid hydrogen leak or spill occurs, a hydrogen cloud could flow horizontally for some distance or even downward, depending on the terrain and weather conditions.