Mich. Comp. Laws § 3.974

Sec. 4. An emergency responder from a unit of government from outside of this state who holds a license, certificate, or other permit recognized or issued by another state shall be considered to be licensed, certified, and permitted to render mutual aid within this state pursuant to a mutual aid agreement authorized by this act, if the emergency responder is acting within the scope of his or her license, certificate, or permit and within what an equivalent license, certificate, or permit from or recognized by this state would authorize.