EMAC, the Emergency Management Assistance Compact, is the nation’s most efficient, effective and preeminent interstate mutual aid system. EMAC acts as a complement to the national disaster response system, providing timely and cost-effective assistance to disaster-impacted states. EMAC does not replace federal assistance, but can be used alongside federal assistance or when federal assistance is not warranted. Requesting resources is made at the discretion of the affected state. Responding to a request for assistance is at the discretion of non-affected states.