Once we remove all the dirt and debris from your system we can apply a solution which is a combination bacteriostat, fungistat, and deodorizer. This product is registered with the EPA to be used in ductwork. The product is fogged through your entire duct system with a special fogging device. The solution is safe for family and pets and can be applied while the home is occupied. If you or someone in your home is sensitive we suggest you check with your physician.