Boston MicroSystems (BMS) proposes to develop a cell-phone sized instrument for detecting hazardous chemical and explosive threats. The instrument is based on BMS' PicoSensor® chemical and explosives detection platform, which has been developed in part under DHS support and is capable of sensing explosives and toxic chemicals at ppb and even ppt (trillion) levels. The Picoensor® consists of a MEMS flow-through preconcentrator integrated via flip-chip packaging with a MEMS sensor array including gravimetric piezoelectric resonators, chemiresistive sensors and capacitive sensors. Using a new BMS innovation, the opportunity now exists to develop ultra-miniature, low power drive-sense electronics and wireless communications for the PicoSensor® using commercial off-the-shelf RF and cellular components. These electronics will be integrated with a rechargeable battery and a miniaturized version of BMS' vapor-phase sampling system, and together allow the PicoSensor®-based instrument to be miniaturized to dimensions of 2" x 4" x ¾". BMS will develop, assemble and deliver to DHS a prototype of the ultra portable instrument for detecting hazardous chemicals and trace explosives by the end of phase II. The miniature instrument will enable ubiquitous chemical and explosives detection as part of large distributed alert networks that improve situational awareness for mission personnel.