Cryogenic Liquefied Gases

Handling cryogenic gases/liquids pose a very serious safety risk.  When referring to cryogenics we are usually talking about gases that are so compressed they become liquids and are extremely cold.  Cryogenic gases/liquids have boiling points below -150 degrees Celsius.  All cryogenic liquids are gases at room temperature and normal pressure. 

The cylinders the gases are stored in are under very high pressure, which poses a large risk.  Due to pressure contained in the cylinders, there is an explosion risk and risk of oxygen displacement/asphyxiation if the gas is suddenly released.  These gases are at such a low temperature they will flash freeze whatever they come in contact with when released.  Cryogenic liquefied gases are handled in extremely insulated and strong containers.  Having such a highly insulated container reduces the risk of evaporation.  Full body protection is recommended when handling these super cooled materials as well as pre-planned medical action and services.  It is important to use only hardware meant for cryogenic materials when dealing with them.  Some equipment may seem suitable at first but does not have the qualifications and can cause an accident.  When an individual is exposed to cryogenic gas the pain is not immediate.  Blood circulation is arrested fairly quickly.  The skin will be severely “burnt” if not completely frozen and infection may result down the line.  Cell deterioration is a large threat because many cells exposed to the extreme temperature will die after thawing.  The reason these gases pose such a high risk of oxygen/air displacement is because of their rate of expansion.  A typical cryogenic liquefied gas will expand from 1 cubic foot to 875 cubic feet when it is released from its container.  Considering an oxygen deficient environment only has to be at or below 19% oxygen to be considered dangerous.  Gas expansion can be a huge risk to human asphyxiation.  If a container is noticed to be leaking, the facility should be evacuated until the threat is no longer existent. 

When these cylinders blow up rapidly (oppose to slowly leaking out) they can cause major damage and danger.  There are scenarios were these containers have gone through cinder block walls and roofs.  This can also trigger a chain reaction. One cylinder can puncture another causing more and more cylinders to explode.  Human lives have been lost this way.  If the compressed gas is flammable it can cause a whole new threat.  If a fire is started the heat surrounding a cylinder can cause the gas/liquid in surrounding cylinders to heat up and expand.  This can cause another chain effect, which has obliterated buildings and facilities in the past.  This is why it is important to take great care in dealing with highly compressed gases.  If tanks are store outside, oxidation of cylinder walls can weaken the tank.  Also, employees must handle them will care being sure not to drop or hit tanks.  If the gas is flammable, a spark resistant wrench should be used when handling the tank.  It is crucial these tanks are equipped with some sort of safety chain when being stored to prevent being tipped over and damaged.