After review of the system growth of a foreign substance has been found covering the inside and outside of the system. Return chase filled with water staining from top of return to the bottom, excess moisture can cause mold/mildew. Unit internally had large amounts of growth covering all components, blower wheel which distributes air was covered in this growth which would have distributed spore particles throughout the ductwork and home causing growth and unhealthy air in other parts of the HVAC system and home. Unit and ductwork should be replaced to make sure no remnants of this growth are left to regrow. These could be mold spores which can have very serious implications for someone’s health if not resolved, proper testing of growth will be important so we can isolate what it is and remove it promptly.