Unattended Use of Bunsen Burner in a Biological Safety Cabinet

Recently, a researcher left a lit Bunsen burner inside a BSC, closed the sash and walked away. The type of biological safety cabinet she was using recirculates about 70% of the air with 30% of the air goes out the exhaust. When the sash is closed there is no bypass to allow fresh air into the cabinet. Thus, no exhaust was leaving the cabinet. Heat within the BSC built up quickly. The situation was discovered only after the flame had burned for a few minutes. The BSC was hot to the touch on the outside. 

  • Experiments with potential danger should never be left unattended, especially when an open flame is involved.  
  • A standard Bunsen burner is only appropriate for open-bench usage. Inside a BSC, an electric furnace such as a Bacti-cinerator, or a device such as the Touch-O-Matic Bunsen Burner should be used. This type of burner is built in a way that a platform is connected to the burner itself. A flame is only produced when the user's hand rests on the platform. When the user's hand moves away, only a pilot light burns. Touch-O-Matic Bunsen Burner also serves the purpose when a continuous flame is needed, the platform only needs to be pressed and slightly twisted. Consequently, the risk of leaving a full flame on by accident is reduced. 
  • Open flames should not be necessary in the near microbe-free environment of a biological safety cabinet. On an open bench, flaming the neck of a culture vessel will create an upward air current which prevents microorganisms from falling into the tube or flask. In a BSC, however, an open flame creates turbulence which disrupts the pattern of HEPA-filtered air supplied to the work surface. Disposable sterile loops (example) should be considered so no flame sterilization is necessary.