Do not permit the use of sealants. Over time sealants will wear off and become airborne. There is little known about the safety of these particles. Also, do not permit the use of ozone as it is known to cause adverse health effects.

Biocidal products (e.g. bleach) are sometimes used to inhibit the growth of unwanted organisms, such as mould and bacteria. Biocides should only be used if there is visible mould in the duct work. Prior to agreeing to the use a biocide, it is recommended that you have a mould expert from a laboratory identify the substance. In addition, make sure to always review the precautions on the biocide label before deciding whether to use it. If you choose to use disinfectants or biocides, always ventilate the area and exhaust the air to the outdoors. In the future, make sure to resolve the moisture problems that facilitated the growth of the mould so that it does not return.