Ill. Admin. Code tit. 80, § 500.220
a) Programs: The Director may establish trainee or apprenticeship programs for new and/or incumbent employees in accordance with the Position Classification Plan or at the request of a department. No trainee position under this Section shall be established in any class other than a trainee class. A trainee or apprenticeship program shall prescribe the purpose, duration, and method of selection and shall include curriculum information and employee benefits in a form and manner required by the Director. A trainee or apprenticeship program may be established for one or more of the following purposes and shall be for a duration not to exceed the limits stated in the class specifications therefor.
c) Limitations on Trainee Appointments: