4-100. Contaminated areas could present a serious hazard to movement near any CBRN incident. One of the key tasks that Army forces may anticipate is establishing and maintaining security around a contaminated area, sometimes known as a hot zone. In an urban area, this task could require a significant amount of resources. This situation requires close coordination with the incident command and unified area command to ensure its proper placement, security, and maintenance. Commanders keep in mind that the contaminated area may shift suddenly due to weather or other factors. Army forces directed to move into a contaminated area plan and rehearse before executing the mission. Ideally, the unit will be equipped for CBRN incidents. Otherwise, if a unit is responding to an emergency, Soldiers should follow the unit standard operating procedure for movement techniques in a contaminated environment.