Fumigation of Biological Safety Cabinets

Decontamination of biological safety cabinets is required prior to maintenance or testing.

(Refer to section 7.9 of AS 2647-1994, Biological safety cabinets – Installation and use.)

Why fumigation is necessary

Internal plenums (spaces) of biological safety cabinets become contaminated by aerosols of hazardous micro-organisms, which have been handled in the cabinet. These internal plenums need to be accessed during testing and maintenance. Fumigation using formaldehyde is the most common and reliable method available for rendering microbiological contamination harmless and thus minimising the risk of personnel exposure to microbiological hazards.

Exceptions

If the cabinet user can guarantee (in writing) that no hazardous organisms have been used in the cabinet since it was last fumigated, we will test the cabinet without prior fumigation.

How a cabinet is fumigated

The following method is based on recommendations of a UK document known as the Howie Report published by Department of Health and Social Security (1983). The cabinet is sealed, usually with plastic film and formalin solution and potassium permanganate mixed in a chamber within the cabinet. The chemical reaction produces formaldehyde vapour which permeates every space within the cabinet and neutralises microbiological organisms over a 12 hour period. The formaldehyde is neutralised by ammonia prior to the cabinet seal being removed.

Application and removal of the fumigation kit should be performed by a trained technician or by any person trained in the safe handling of chemicals and equipment in a laboratory and equipped with appropriate protective devices.

Total Air Care can provide fumigation kits complete with instructions.