EPA Form EPA-4U24, October 1997

NYC 9/11 Public Portal Document

are also registered for use as sanitizers and some growth on a settling plate is on hard surfaces, which could include normal. As noted earlier, only an expert the interior of bare sheet metal ducts. can positively identify a substance as While many such products may be used biological growth and lab analysis may legally inside of unlined ducts if all label be required for final confirmation. Other directions are followed, some of the testing methods are not reliable. directions on the label may be inappropriate for use in ducts. For / Explain why biological growth example, if the directions indicate “rinse cannot be removed by physical with water,” the added moisture could means, such as brushing, and further stimulate mold growth. growth prevented by controlling moisture. All of the products discussed above are registered solely for the purpose of If you decide to permit the use of a sanitizing the smooth surfaces of biocide, the service provider should: unlined (bare) sheet metal ducts. No products are currently registered as bio­ ✓ Show you the biocide label, which cides for use on fiberglass duct board will describe its range of approved or fiberglass lined ducts, so it is uses. important to determine if sections of your system contain these materials / Apply the biocide only to un-insu- before permitting the application of any lated areas of the duct system after biocide. proper cleaning, if necessary to reduce the chances for regrowth of mold following cleaning. No products are currently registered by ✓ Always use the product strictly EPA as biocides for use on fiberglass according to its label instructions. ductboard or fiberglass lined ducts so it is important to determine if sections of your While some low toxicity products may be legally applied while occupants of system contain these materials before the home are present, you may wish to permitting the application of any biocide. consider leaving the premises while the biocide is being applied as an added precaution. Do sealants prevent the release of In the meantime... dust and dirt particles into the air? Before allowing a service provider to KA anufacturers of products marketed use a chemical biocide in your duct IVI to coat and seal duct surfaces work, the service provider should: claim that these sealants prevent dust and dirt particles inside air ducts from ✓ Demonstrate visible evidence of being released into the air. As with microbial growth in your duct work. biocides, a sealant is often applied by Some service providers may attempt to spraying it into the operating duct sys­ convince you that your air ducts are tem. Laboratory tests indicate that contaminated by demonstrating that the materials introduced in this manner microorganisms found in your home tend not to completely coat the duct grow on a settling plate (i.e., petri dish). surface. Application of sealants may This is inappropriate. Some microor­ also affect the acoustical (noise) and ganisms are always present in the air. fire retarding characteristics of fiber-

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