2.5.4.5.3. CBRN Survivability Considerations. The sponsor shall clearly state whether the proposed solution will be required to operate in CBRN (including EMP) environments and ensure required CBRN operations are addressed in any follow-on AoA(s). The sponsor determines if the resulting system is "mission critical" or not. If "mission critical" and the system is vital to an essential defense mission that is required survive and/or operate in CBRN environments, the sponsor will designate the system "CBRN Mission Critical" per Reference DoDI 3150.09, Reference [77]. Additionally, the sponsor must include rationale justifying when a "Mission Critical" system is not designated "CBRN Mission-Critical." CBRN Mission Critical systems must consider all relevant CBRN environments (as indicated in the threat section).