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 10 4 reduction in viability was achieved for each group offive 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 10 4 . 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.

Validation Study for the Use of Chlorine Dioxide Gas as a Decontaminant for Biological Safety Cabinets

“…Several studies have monitored the efficacy of formaldehyde (Abraham et al, 1997;Fink et al, 1988;Munro et al, 1999;Taylor et al, 1969). These generally involved the use of bacterial endospore biological indicators (BIs).…”

Primary Containment (Chapter 3)

“…Gaseous decontamination is usually done by heating paraformaldehyde flakes in a sealed cabinet to release formaldehyde gas. This must be done carefully to prevent formaldehyde leakage into the laboratory and to achieve the intended kill of infectious agents (Fink, 1988;Abraham, 1997).…”

Impact of NSF/ANSI 49 and Risk Assessment on Exposure Frequency to Formaldehyde during Decontamination of Biological Safety Cabinets at U.S. Naval Medical Research Unit No. 3, Cairo, Egypt

“…This must be completed carefully to prevent formaldehyde leakage into the laboratory and to achieve the intended killing of infectious agents (Abraham et al, 1997;Fink et al, 1988). Due to the excessive residue of the neutralized formaldehyde gas, extensive cleaning must be done after decontamination and before use (Lin et al, 1999).…”