Block MEMS LLC, a developer of quantum cascade laser-based IR detection systems, has been awarded a $3.5 million contract from DARPA as part of the SIGMA+ program. Under this contract, Block MEMS will leverage its eye-safe laser capability to generate chemical detection maps via standoff sensing in a complex 3D urban topography. SIGMA+ builds on DARPA's previous SIGMA program, which began in 2014 as an effort to significantly advance scalable detection capabilities to counter the threat of radiological and nuclear weapons of mass destruction. SIGMA developed thousands of high-capability, low-cost detectors and networked them to demonstrate large-scale, continuously-streaming physical sensor networks. The work of the new program will be done under a collaborative effort led by SRI International and called Localization and Characterization of Chemical Anomalies in Urban Settings (LOCCUS), which will combine SRI's point sensing technology with Block's standoff sensing technology to deliver an adaptive, high-sensitivity, ruggedized detection capability that exceeds current chemical sensing capabilities. The goal of the program is to develop a persistent, real-time, early detection system for threats in the full spectrum of chemical, biological, radiological, nuclear, and explosive weapons of mass destruction at the city-to-region scale.