Division 2, Good Manufacturing Practices (GMP), of the Food and Drug Regulations does not specifically require manufacturing facilities for non-sterile drugs to maintain HEPA filtered air. The Regulations do require the use of equipment for adequate control over air pressure, microorganisms, dust, humidity and temperature, when appropriate. In addition, this section calls for use of air filtration systems, including pre filters and particulate matter air filters on air supplies to production areas, as appropriate. These provisions speak to measures to prevent cross contamination, and the key phrase is “when appropriate”. Despite the lack of an explicit GMP requirement, some firms may elect to use HEPA filtered air systems as part of their dust control procedures. For example, firms may perform dust containment assessments and decide that such filters are warranted to prevent cross contamination of highly potent drugs that, even in small quantities, could pose a significant health hazard when carried over into other products.