Students examine M8 Chemical Agent Detector Paper for the presence of liquid chemical agents during a Chemical, Biological, Radiological and Nuclear Defense (CBRN) Survival Skills Training course on Joint Base Andrews, Md., Feb. 14, 2013. M8 paper turns green, red or yellow depending on the agent detected. (U.S. Air Force photo/Airman 1st Class Nesha Humes)(Released)