| Cryotubes used to contain samples stored under liquid nitrogen may explode without warning. Tube explosions are thought to be caused by liquid nitrogen entering the tube through minute cracks and then expanding rapidly as the tube thaws. UC Berkeley and Lawrence Berkeley Laboratory have reported several serious accidents due to tube failure. Researchers have had plastic embedded in their eyes, faces and hands. A/S Nune cryotubes manufactured between June 1979 and June 1981 have been recalled. Tubes from other manufacturers fail periodically. | 
