Operator induced biological contaminations in cell culture is a multifaceted problem involving the unex-pected introduction of other animal cells (see chapter by Masters), microbial (see chapter by Drexler and Uphoff), and viral contaminants. There are few reports on operator induced viral contaminations. The potential exists, however, as reports have appeared documenting the considerable stability of Rhinoviruses, Respiratory Syncytial virus, Rotaviruses, and others, in aerosols on worker's hand and safety hood surface (for more details, see Hay, 1991) .