A contaminant detection system for mail is provided. A mail piece enters the system according to the present invention and a probe is inserted into the mail piece. An extraction device, such as, for example, a vacuum system, extracts a sample of air, including any dust and other particles, from inside the mail piece. The extracted sample is provided to a sampling system that monitors for the presence of a possible contaminant. If any type of contaminant is found in the sampled air, dust and other particles, a signal can be provided to alert an operator of contaminant detection and the mail piece can be diverted and held for further investigation. If no contaminants are detected, the mail piece is accepted and delivered to a normal processing path.