4-106. CBRN personnel contribute to the overall protection of units located in defensive positions. CBRN personnel perform CBRN vulnerability assessments including a threat assessment and vulnerability analysis, and they recommend vulnerability reduction measures for commanders to consider before and after units move into their defensive positions. These assessments provide a list of preventive measures that can range from the use of obscurants, reconnaissance, mission-oriented protective posture, and other aspects of CBRN defense. (For more information on CBRN vulnerability assessment, see ATP 3-11.36. For more information on CBRN protection, see ATP 3-11.32.)