The document summarizes a full-scale regional exercise held in 2009 to test the Chempack system for responding to a mass casualty chemical incident. The exercise involved multiple hospitals, emergency response agencies, and public health organizations across Region D. Key capabilities that were tested included emergency management planning, communications, safety/security, staff responsibilities, and patient management. Participating organizations provided positive feedback on communication channels and identified opportunities to improve transport protocols and additional training. The regional poison control center also participated and gained experience handling a high volume of exposure calls over a short period during the simulated incident.