The Effectiveness of Gaseous Formaldehyde Decontamination Assessed by Biological Monitoring

Abstract

The results of seven years experience of the effectiveness of routine gaseous formaldehyde decontamination of rooms, filter canisters and biological safety cabinets at ambient temperature are reported. The effectiveness of each decontamination was monitored biologically by the inactivation of Bacillus stearothermophilus spores at five locations in rooms and biological safety cabinets and at two locations in filter canisters. A greater than 104 reduction in viability was achieved for each group of five spore tests in 92% of room decontaminations and each group of five spore tests in 81% of biological safety cabinet decontaminations, and a greater than 104.7 reduction for both spore tests in 83% of filter canister decontaminations. This long-term study of 2,308 routine formaldehyde decontaminations of varying spaces in practical situations demonstrates the reliability of the procedure. The results confirm that previously-described methods can be applied with confidence for routine decontaminations of laboratory facilities and equipment.