![]() Flesh will stick to extremely cold materials. Never touch non-insulated vessels containing cryogenic liquids.A tightly sealed container will build up pressure as the liquid boils and may explode after a short time. Only store liquid nitrogen in containers with loose fitting lids (Never seal liquid nitrogen in a container).Materials such as carbon steel, plastic and rubber become brittle at these temperatures. Impact resistant containers that can withstand the extremely low temperatures should be used. Do not transport liquid nitrogen in wide-mouthed glass Dewars or Dewars not protected with safety tape.Use tongs to withdraw objects immersed in a cryogenic liquid - Boiling and splashing always occur when charging or filling a warm container with cryogenic liquid or when inserting objects into these liquids. Handle the liquid slowly to minimize boiling and splashing.Liquid nitrogen should be handled in well-ventilated areas.Use a pressure relief vessel or a venting lid to protect against pressure build-up. Users must make sure that cryogenic liquids are never contained in a closed system. ![]() Without adequate venting or pressure-relief devices on the containers, enormous pressures can build upon cryogen evaporation. Condensed oxygen in a cold trap may combine with organic material in the trap to create an explosive mixture. Equipment containing cryogenic fluids must be kept clear of combustible materials in order to minimize the fire hazard potential. Since the boiling point of nitrogen is lower than oxygen’s, liquid oxygen evaporates slower than nitrogen and may build up to levels which can increase the flammability of materials such as clothing near the system. When transferring liquid nitrogen, oxygen in the air surrounding a cryogen containment system can dissolve and create an oxygen-enriched environment as the system returns to ambient temperatures. To prevent asphyxiation hazards, handlers have to make sure that the room is well ventilated when using cryogens indoors. Death may result if oxygen deficiency is extreme. Hence, if sufficient liquid nitrogen is vaporized so as to reduce the oxygen percentage to below 19.5%, there is a risk of oxygen deficiency which may cause unconsciousness. Liquid nitrogen expands 695 times in volume when it vaporizes and has no warning properties such as odor or color. The vapor of liquid nitrogen can rapidly freeze skin tissue and eye fluid, resulting in cold burns, frostbite, and permanent eye damage even by brief exposure. The principal investigator (PI) or the lab manager is responsible for developing and implementing standard operating procedures (SOPs) for the purchase, storage, and safe handling of this chemical that are specific to the PI’s research.Ĭontact information and areas of expertise can be found on the Contact Us page. This generic chemical safety guidance describes basic prudent safety practice for handling this chemical in research labs. It is liquefied under high pressure condition and can expand to a very large volume of gas. As “cryogenic” means related to very low temperature, it is an extremely cold material. Liquid nitrogen is one of the cryogenic liquids commonly used in research labs. ![]()
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