An EMP-protective composite structure may include at least one enclosure having walls, a ceiling, at least one ingress/egress portal and a base, each including at least one blast-resistant structural panel and at least one layer of an EMP barrier having CCR that provides magnetic conduction, field absorption, and field reflection fully-enclosing the structural panel. A blast- resistant structural panel may include a frame constructed of a spaced-apart frame members of a ferrous material, frame reinforcing members extending between the frame members, a cementitious layer in which the frame is embedded, and an EMP absorbing mesh embedded in the cementitious layer. The composite structure may further include an encapsulation barrier and a HEMP protective door formed in the enclosure to absorb and deflect HEMP.