The purpose of this United States US Federal Emergency Management Agency FEMA guidebook, the National Incident Management System Emergency Operations Center How-To Quick Reference Guide August 2021, is to be an all-hazards how-to guide to provide state, local, tribal and territorial (SLTT) jurisdictions with information and guidance related to setting up, operating, maintaining and deactivating an EOC that successfully meets the jurisdiction's needs. This guidance applies an all-hazards approach in its concepts, processes and principles. FEMA recognizes that certain hazards may have specific implications, precautions and instructions that take effect under certain conditions and threat environments.