Biohazard potential: recovery of infectious virus from the liquid nitrogen of a virus repository

Flame-sealed glass ampules containing vesicular stomatitis (VSV) were submerged in a liquid nitrogen (LN2) refrigerator for storage. Onseveral occasions cracked or shattered ampules were discovered upon removal from the refrigerator. Subsequently, VSV was recovered from the LN2 of the virus repository indicating a source of potential danger to those employing glass ampules submerged in LN2 for preservation of pathogenic organisms.