L & O Air Duct Cleaning Company is the known company that does not make use of any chemicals that make their habitat inside the duct system. We do not squirt any chemicals and effort to kill mold or any other biological expansion. Proper remediation practice we adopt is to do away with the contamination from the system. Depending on the category of duct work, a precautionary product with anti-microbial could be used as an alternative to put off future biological growth.