20 ILCS 3305/16
If such disaster as is described in Section 4 occurs in this State and the services of persons who are competent to practice any profession, trade or occupation are required in this State to cope with the disaster and it appears that the number of persons licensed or registered in this State to practice such profession, trade or occupation may be insufficient for such purpose, then any persons who are licensed elsewhere to practice any such profession, trade or occupation may, if a member of a mobile support team or unit of another state rendering aid in this State pursuant to the order of the Governor of their home state and upon the request of the Governor of this State, or if otherwise requested so to do by the Governor or the Director of this State, during the time the disaster continues, practice such profession, trade or occupation in this State without being licensed or registered in this State.
20 ILCS 3305/16