Is there only one minimum standard for storage requirement for all levels of classified materials?

No, there is not a single minimum standard for storage requirements for all levels of classified materials. Different classifications, such as Confidential, Secret, and Top Secret, have varying storage standards and security measures based on the potential impact of unauthorized disclosure. Each level has specific guidelines outlined in regulations like the National Industrial Security Program Operating Manual (NISPOM) and other federal directives to ensure appropriate protection.