WASHINGTON, DC — In mid-March, the director of the Office of Pesticide Programs for the U.S. Environmental Protection Agency (EPA) released an open letter to organizations representing the hvacr community. The letter, signed by director Marcia Mulkey, addressed the EPA’s concern for the use of disinfectants, sanitizers, and other types of antimicrobial products to treat the surfaces of hvacr systems.

In the letter, Mulkey states that the EPA has not yet been able to determine whether such products are effective. She also notes that the agency has yet to assess the potential risks to building occupants associated with the use of disinfectant products on ductwork.

The following are some excerpts from Mulkey’s letter.

“The purpose of this letter is to bring to your attention several concerns that the Agency has regarding the possible use of sanitizer and/or disinfectant products, and possibly other types of antimicrobial products, to treat the surfaces of [hvacr] systems, typically as part of air duct cleaning.…

“We are particularly concerned because the Agency has not assessed the potential exposure and risks to building occupants or applicators from the use of these products in or on any surfaces that are part of hvacr systems in circumstances where the labels do not specifically authorize use in hvacr systems. Also, the Agency has not assessed whether such products are efficacious when used in hvacr systems. Therefore, users cannot assume that EPA registration of these products reflects any conclusions about their safety or effectiveness in this situation. 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.

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

“We believe that all these factors may contribute to possibly unlawful and/or uninformed use of these products, which could have implications for public health and safety and for consumer protection.

“We are writing to you because we believe you would share our concerns about the possibility that these products may be used as pesticides in a manner not authorized by the label and not contemplated by the pesticide registration process. We also believe that you wish to ensure that these products are not being used in a manner which might be harmful to applicators and/or building occupants.

“We recommend that you advise your members not to apply disinfectant, sanitizer, or other antimicrobial products to treat hvacr systems if such product does not include specific directions for hvacr use.”


“The agency has prepared this letter to place the industry on notice regarding manufacturers’ obligations to protect their users and customers,” said Robert Baker, chairman and ceo of BBJ Environmental Solutions, Inc. (Tampa, FL). “It is appropriate to review both the label and advertising literature for any products you carry that make claims to kill or control mold, bacteria, or other living organisms.”

Baker stated that there are “many reasons” for Mulkey’s letter.

The first reason is “to inform the user community that a product labeled for a hard, nonporous surface does not include the hvac system,” he said. “Second, hvac use requires detailed use directions on how, when, and how much to apply.

“Third, a much more detailed exposure and risk analysis is needed for an hvac use, since large numbers of people could be potentially exposed to the chemical. Finally, efficacy data may be required to show that the product can be delivered throughout the system and will work.”

Baker advised that contractors check out the following points before making a product purchase:

  • Is the product being sold or promoted for use in hvacr systems? If so, does the label contain clear directions for use in these systems? If the directions just talk about “hard surfaces,” further investigation is necessary.

  • Do the label’s claims and directions match and make sense? (For example, the directions should describe how to apply the product to an air conditioning system.) Directions requiring the product to be rinsed off following application can be a problem, because some air conditioning system components are difficult to rinse without causing damage.

  • Does the label claim that the product can be used in ducts? That should be a cause for concern, as agency representatives are reviewing all products that might have been cleared in the past with “duct use” language. They do not feel that the product review process in place at that time considered all of the possible risks connected with duct usage.

    As far as their use in hvacr systems goes, “The future of such products is unclear at best,” said Baker. “The EPA is currently working on a PR notice regarding hvac air duct use. This notice may be available in draft form for public comment late summer or fall this year. Just a few of the contractors have gotten the word, and most are still trying to figure out how the policy direction impacts them,” Baker said. “Publications like The News will help to get the word out.”

    For more information from the EPA on hvacr applications, contact Tracy Lantz at 703-308-6415. The number for the EPA’s Antimicrobial Hotline is 703-308-0127.

    Publication date: 04/08/2002