If heating, ventilation, and air conditioning mechanical systems are insufficiently maintained, their metallic surfaces can provide the organic matter mold needs to grow.

However, mold in the ductwork can be treated. If the technician identifies mold in the ductwork system during the air duct cleaning process, he/she will show the client and recommend the use of sanitizer, a chemical solution approved by the EPA for mold remediation within the ductwork. The mold will  be agitated and removed manually. The technician will then use a fogger, an electric device that coats the ductwork with the sanitizer to remediate the remaining mold.

Sanitizing ones duct system stems microbial growth such as mold and bacteria and is  is often used when people have allergies or are moving into a previously occupied home.