In this Environmental Assessment (EA), the National Nuclear Security Administration (NNSA) proposes to design and build a new emergency response facility to support the Y-12 National Security Complex (Y-12) missions. The proposed action would consolidate the Plant Shift Superintendent’s (PSS) Office, the Emergency Command Center (ECC), the Technical Support Center (TSC), and the Fire Department Alarm Room (FDAR) from their present locations to a single facility that meets current DOE orders, is survivable and sustainable for 72 hours, and achieves the U.S. Green Building Council’s Leadership in Energy and Environmental Design (LEED) Gold Certification.