Problem

The UCIAQ Committee discourages the use of chemical sanitizers or biocides to treat building supply and return duct work. Although many antimicrobial products are EPA approved for use on hard, non-porous surfaces, these products were not specifically designed for use in HVAC systems and have not been evaluated for potential occupant health exposure issues. Any use of chemical sanitizers or biocides in duct work should be carefully reviewed by a health and safety professional prior to treatment. Problems involving visible fungal growth inside duct work must be addressed by first determining the source of moisture and correcting this problem. Following correction of the moisture problem, the system can be cleaned using mechanical techniques and detergents. Porous HVAC system materials such as insulation or fabric filters contaminated with visible fungal growth should be discarded and replaced.