Maxion Technologies, Inc. (Maxion) proposes to develop and field test a Carbon Monoxide (CO)-sensor prototype for post fire cleanup and CO detection. The sensor will have the dynamic range required to detect and monitor CO from approximately 1 to 500 ppmv with a resolution to 1 ppmv. Maxion will grow, fabricate and test a Quantum Cascade Laser (QCL) at a unique single-mode wavelength ideal for CO detection. Maxion will team with Physical Sciences Inc. (PSI) to integrate the QCL into PSI's Wavelength Modulation Spectroscopy (WMS) platform. The WMS sensor board, previously developed for near-IR lasers, will be redesigned to accommodate QCL lasers. The QCL will be specially designed and fabricated for minimum power consumption. In Phase 1 the QCL was incorporated into the WMS platform and tested on a breadboard level. The breadboard sensor demonstrated the necessary dynamic range and easily surpassed the required minimum sensitivity. A Phase II prototype design was made based on the Phase I results for which dynamic range, sensitivity, SWaP, and operation with a high degree of reliability, minimal maintenance, and self-calibration under varying humidity and ambient pressures are primary design features. The sensor prototype will be tested in a relevant environment with controlled burns at a NASA test facility. Upon successful completion of all field tests, the TRL will be 6 at the end of Phase II.