2. Cryogenic storage: Because of its extremely cold temperature, liquid nitrogen can be hazardous if improperly used. When handling liquid nitrogen, take precautions to protect your eyes, face, and skin from exposure to the liquid. Wear protective clothing, including a laboratory coat, gloves designed for handling material at cryogenic temperatures, and a face shield. To reduce your exposure to cryogenic temperatures, design inventory systems for storing frozen specimens that allow for easy retrieval and that minimize the time required to look for specimens. Prolonged exposure to cryogenic temperatures can lead to a loss of sensation in the hands that can only be recovered after vv arming. This loss of sensation can lead to a false sense of security regarding damage to tissues by the low temperatures. When the temperature in a liquid nitrogen unit becomes tolerable and working in the unit is no longer uncomfortable, the operator has reached a point where damage from the cryogenic temperatures is likely. When liquid nitrogen is used in confined and inadequately ventilated areas, the nitrogen can quickly displace the room air. Liquid nitrogen freezers should be located in well -ventilated areas, and special precautions should be taken during fill operations. In facilities with several liquid nitrogen freezers, an oxygen monitor should be installed to warn occupants of any deterioration in the air quality due to the nitrogen gas. Plastic screw-capped vials can present a hazard if stored directly in liquid nitrogen. Vials with an inadequateseal between the cap and the vial can fill with liquid nitrogen. Upon retrieval to warmer 150 Kumar, Kashyap, Singh, and Srivastava temperatures the vials may explode violently or may spray liquid, potentially disseminating the contents of the vial. Like wise when opening plastic vials after thawing some dissemination of the contents may occur. Therefore, material in plastic ampoules should be stored in the vapor above the liquid nitrogen.