5 ILCS 235/20
Any function performed by an emergency responder that is (i) acting within the scope of his or her license, certificate, or permit and within the scope of what an equivalent license, certificate, or permit recognized by this State would authorize and (ii) pursuant to a mutual aid agreement authorized by this Act shall be deemed to have been for public and governmental purposes, and all liabilities and immunities from liability applicable to this State's political subdivisions and their officers and employees shall extend to the emergency responders from another state while providing mutual aid during a mutual aid emergency or while engaged in training exercises pursuant to a written mutual aid agreement authorized by this Act. This Section shall not provide greater immunities to emergency responders from outside of this State than those immunities provided to emergency responders with the equivalent license, certificate, or permit in this State. This Section shall only apply to causes of action accruing on or after the effective date of this Act.
5 ILCS 235/20