The Biohazard Detection System deployed by the USPS is a decentralized locally networked automated collection and identification system and is used to detect the biological agent causing anthrax that could be present in first-class mail. The system is installed in mail processing facilities nationwide. The system is integrated with mail processing and letters are automatically fed into the system where it detects the presence of anthrax. The detecting process runs continuously and alerts system operators if a presumptive positive case of anthrax is detected.