This United States Army field manual, Army Techniques Publication ATP 3-11.74 Chemical, Biological, Radiological, and Nuclear Platoons April 2021, provides fundamental tactics, techniques, and procedures (TTP) for planning, preparing, and executing platoon operations within chemical, biological, radiological, and nuclear (CBRN) platoon formations. It incorporates current doctrine for large-scale combat operations and provides the doctrinal tools to execute platoon missions. ATP 3-11.74 provides CBRN platoon leaders and platoon sergeants with a doctrinal reference to assist them in successfully accomplishing any assigned mission. Although focused on the platoon level, this ATP also applies to CBRN detachments and CBRNE response teams (CRT). These units are smaller than a CBRN platoon but the level of their operations are similar to the CBRN platoon. The officers and noncommissioned officers in charge of these elements should refer to the equivalent platoon leader and platoon sergeant responsibilities in this manual. This publication is designed for use at the tactical level. It applies to active and reserve components and supports command staffs and platoon leadership performing assigned missions and tasks. ATP 3-11.74 applies to the Active Army, Army National Guard/Army National Guard of the United States, and the Army Reserve unless otherwise stated.