WARNING! Do not use cryogenic vials for storage in the liquid phase of liquid nitrogen unless correctly sealed in Nunc CryoFlex tubing. Such use may cause entrapment of liquefied nitrogen inside the vial and lead to pressure build-up resulting in possible explosion or biohazard release. Use appropriate safety procedures as outlined in the NALGENE Cryopreservation Manual when handling and disposing of vials. Request Lit. No. 10096 or download a copy from www.nalgenelabware.com.