A Air Conditioning and Heating Company found white powder found on the floor of the homeowner house after AC system installation. They received a complaint from one of the homeowners about unidentified powdery material found on the floor of the newly finished house. The homeowner accused our client that the contamination was caused by the new AC unit. Laboratory testing showed the presence of fibrous glass, minerals, and crystal-like material. Advanced analytical techniques identified the crystal-like material as Aluminium Oxide, and majority of minerals as particulates related to the construction type materials. Based on our findings client was able to prove that contamination was not related to the AC unit but was caused by the aluminum oxide based sandpaper used by the contractor.