Cryogenics

Cryogenics are materials whose substances must be cooled at an extremely lower temperature to change from a gas state to a liquid state. Some examples of some common cryogenics include liquid nitrogen, helium, hydrogen, argon, methane, and more. They have an extremely low temperature and a relatively high expansion rate when it changes from liquid to gas. Due to these conditions, it makes it extremely difficult and challenging to work with and is comprised of health and safety concerns for those working with cryogenics. Anyone working with this type of material must be fully aware of the hazards that come with it and what precautions to take to remain safe.

Hazards to cryogenics include ultra cold temperatures, flammability, asphyxiation, and high-pressure gas that can result in over-pressurizing of containers.

(http://www.heattreating.com/value-added-services/cryogenics/)

Example of a possible dangerous workplace with cryogenics. 

One significant occupational exposure hazard is burns and frostbites from handling cryogenics. This type of damage is able to occur within a few seconds of contact with any tissue. Spilling cryogenics could result in hypothermia of those who are exposed. Using the appropriate PPE when working with this type of material is extremely important to protect workers from the danger cryogenics can produce. Another hazard risk is its flammability. Cryogenics are associated with fire and explosion hazards and some of these gases include hydrogen, methane, and acetylene. Oxygen has the ability to accelerate these gases and make them even more hazardous when working with cryogenics. There should be no use of ignition source while working with cryogenics and electrical equipment should also be considered. Any combustibles or flammables should stay away from any source of oxygen. Liquefied inert gases and extremely cold surfaces should also be managed in a way that doesn't create the probability of having oxygen condensing from the atmosphere. Any high pressured gas should be eliminated when dealing with cryogenics. This is because cryogenics are usually stored near there boiling points, interacting with the high pressured gas could result in an explosion. Also, when the liquid form evaporates, it creates a build up of high pressure that could be potentially dangerous.  The evaporation rate will depend on numerous variables including the fluid, storage container design, and environmental conditions but most importantly, the container must include the capacity that it is capable of producing when the liquid turns into a gas form. Ensuring pressure relief devices are used properly and maintained/checked regularly to ensure that there is no leaks or damages. These should be test to see the possible back pressure from the cryogenics as well. Due to the large expansion that takes place when the cryogenic liquid transforms into a gas, the displacing of breathable air is able to form. Long periods of breathing pure oxygen can have harmful effects on the body. Because of this natural ventilation should be used and transporting or using containers with cryogenic material in enclosed spaces should be avoided. 

(http://www.ehs.ucsf.edu/cryogenic-liquids)

Effects of cryogenics on a worker's hand. 

Because of the dangers associated with working with cryogenics, minimizing staff exposure potentials are extremely important as well as the implementation of administrative controls, Personal Protective Equipment (PPE), work methods, and engineering controls.