Use of Disinfectants and Sanitizers in Heating, Ventilation, Air Conditioning, and Refrigeration Systems

Supplemental Guidance – Use of Disinfectants and Sanitizers in Heating, Ventilation, Air Conditioning, and Refrigeration (HVAC&R) Systems

EPA, September 30, 2010

The purpose of this guidance is to supplement the March 14, 2002 letter from Marcia Mulkey, former Office of Pesticide Programs Office Director at the EPA, which identified several Agency concerns regarding the use of sanitizers, disinfectants and other types of antimicrobial products to treat the surfaces of heating, ventilation, air conditioning and refrigeration (HVAC&R) systems, typically as part of air duct maintenance or cleaning. The intent of the supplemental guidance is to ensure that users, applicators and registrants are only using products labeled for use in HVAC&R systems. The Agency is providing this supplemental information because HVAC&R systems represent a unique use site and the Agency concerned about potential risks to applicators and building occupants that may be associated with the use of antimicrobial products in such settings.

The Agency believes that certain types of antimicrobial products not registered for use in HVAC&R systems are being used in a manner not authorized by the label and not assessed by the Agency as part of the pesticide registration or amendment process. Although the directions for use of most registered sanitizer and disinfectant products permit use on hard non-porous surfaces, because of the uniqueness of HVAC&R systems, such directions for use do not include use on or in HVAC&R components or surfaces unless such HVAC&R use is specifically included on the label.

Unique Use Site and Exposure

The Agency believes that application of an antimicrobial product to an HVAC&R system represents a use pattern that is substantially different from other hard surface disinfection or sanitizer uses.

  • First, an HVAC&R system needs to be inspected cleaned and/or duct work needs to be repaired to ensure that the system is in sound mechanical condition prior to treatment with an antimicrobial product. These specific label instructions are not found on a typical antimicrobial product.
  • Second, the methods used to treat HVAC&R systems, as well as the application equipment used, are substantially different from those found on the label of a typical antimicrobial product that may be applied to hard non-porous surfaces.
    • Many antimicrobial products are applied to hard surfaces as either a ready-to-use spray or as a diluted liquid using a sponge, towel or other means to spread the material over the surface.
    • An HVAC&R system application is often made using an Ultra Low Volume (ULV) or mist generating sprayer or through the use of an automated spraying system sometimes carried by robots through air ducts.
    • These methods of application are substantially different from the conventional use of antimicrobials to treat hard non-porous surfaces.
  • Finally, many of the components of HVAC&R systems are typically inaccessible, which could create unique exposure scenarios for applicators, and label directions responsive to such considerations are not found on the label of a typical antimicrobial product.

Risk Assessment and Registration

The Agency needs to conduct a risk assessment before it can decide whether an applicant for registration (or amendment to a registration) can include HVAC&R system use on the product label. In the absence of adequate data to enable appropriate review and evaluation of these products, it is possible that use of these products in HVAC&R systems could lead to significant exposures in indoor environments with potentially unreasonable adverse effects. Agency review and assessment of a HVAC&R system use may identify mitigation measures (e.g., label changes) that may be required if risk concerns are identified. In addition, the Agency’s risk assessment will help ensure that the most sensitive populations, such as infants and children, will not be negatively impacted from pesticides that are used to treat HVAC&R systems.

To support an application for such a registration or amendment to a registration, adequate and appropriate directions for HVAC&R system use should be submitted and include specific proposed directions for use addressing the following:

  • Method of application.
  • Type of application equipment.
  • Application dosage rate.
  • Target organism.
  • Frequency and timing of application to obtain effective results.
  • Worker protection information (such as Personal Protective Equipment).
  • Possible Re-entry restrictions (covering applicators and occupants of the treated facility).

If a public health claim is made, such as a sanitizer or disinfectant claim for duct work, then efficacy data must be submitted to support the proposed claim. In such a case, the Agency may need to review a protocol prior to submission of a registration application. Among other things, the protocol would have to address how the product will be applied to ensure that all the duct work will be treated. In addition, the protocol would need to address how the surface will remain wet for the required product contact time.

The Agency encourages a pre-registration meeting for those interested in registering a product for HVAC&R system uses or for adding this use to a previously registered product label.

Letter Regarding Use of Disinfectant Products in HVAC&R Systems

March 14, 2002

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 heating, ventilation, air conditioning, and refrigeration systems (HVAC&R), typically as part of air duct cleaning. First, although the directions for use of most of these products permit use on hard, non-porous surfaces, such directions may not specifically include the use of the product in HVAC&R systems.

We are particularly concerned about this possibility 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 HVAC&R systems in circumstances where the labels do not specifically authorize use in HVAC&R systems. Also, the Agency has not assessed whether such products are efficacious when used in HVAC&R 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 HVAC&R 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 HVAC&R “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.

In the absence of adequate data and the associated review and evaluation of the registration process, use of these products in HVAC&R systems could lead to significant exposures in indoor environments with potentially unreasonable adverse effects. One indication of the potential scope of the problem is the fact that the National Antimicrobial Information Network has reported to us that it received about 150 calls related to the possible application of antimicrobial pesticide products in HVAC&R systems in a recent 18 month period.

We are writing to you because we believe you would share our concerns about the possibility that these products may be being 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 HVAC&R systems if such product does not include specific directions for HVAC&R use. The Agency believes that it is important that you ensure that members of your association are not applying products to HVAC&R systems which are not registered for that use. We intend to further evaluate this use to determine the potential exposure and risks as well as the efficacy criteria which are required before pesticide products are registered to be used in HVAC&R systems.

We recognize that it is important to address the labeling of these products, and we intend to work with pesticide registrants to assure that these product labels clearly communicate the uses which EPA has (and has not) authorized. We also expect to assure that appropriate evaluations of risk and effectiveness accompany any authorized uses in these systems. However, we felt it was important to inform you of these issues promptly, without waiting for any further revisions of these product labels and the conditions for their registration.

We hope you will find this information of value to you and your company as part of your approach to serving your customers. Feel free to contact Tracy Lantz at (703) 308-6415 if you have any questions.

Marcia E. Mulkey, Director

Office of Pesticide Programs – March 14, 2002

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