A recent U.S. EPA letter warned RSES members and the hvacr industry not to use unapproved hvacr antimicrobial products.

A recent letter from the U.S. Environmental Protection Agency warned Refrigeration Service Engineers Society members and the hvacr industry to not use disinfectants, sanitizers, or other antimicrobial products not registered for use in hvacr systems.

EPA said it has several concerns about the use of these and other types of antimicrobial products, typically designed for air duct cleaning. Although the directions for most of these products permit use on hard, nonporous surfaces, such directions may not include their use in hvacr systems.

"The agency (EPA) has not assessed the potential exposure and risks to building occupants or applicators from the use of these products in or any surfaces that are part of the hvacr systems in circumstances where the labels do not specifically authorize use in hvacr system. Also, the agency has not assessed whether such products are efficacious when used in hvacr systems," said Marcia E. Mulkey, director of the EPA's Office of Pesticide Programs.

Mulkey warned that users of the products cannot assume that EPA registration of these products reflects any conclusions about their safety or effectiveness for hvacr systems.

"Even in circumstances where labels do list hvacr systems as a possible use, we are concerned that the agency has not received and reviewed adequate data to fully evaluate risks to building occupants or product efficacy in that use pattern," she said.

An additional source of concern arose because some pesticide products also bear labels that identify the product as hvacr "cleaners." This could further increase the likelihood that users incorrectly made pesticidal use of such products or make incorrect assumptions about the status of EPA review, evaluation, and conclusions about them, EPA said.

EPA said it intends to further evaluate the use of pesticides in hvacr systems to determine the potential exposure and risks as well as the efficacy criteria that are required before pesticide products can be registered to be used in such systems. In the meantime, RSES has encouraged its members to heed the EPA warning.