40 ILCS 5/15-152
Disability benefits shall be discontinued when the earliest of the following occurs: (1) when disability ceases, (2) upon refusal of the participant to submit to a reasonable physical examination by a physician approved by the board, (3) upon refusal of the participant to accept any position, assigned in good faith by an employer, the duties of which could reasonably be performed by the participant and the earnings of which would be at least equal to the disability benefit payable under this Article, (4) upon September 1, following the participant's 70th birthday, if the disability benefit commenced prior to attainment of age 65, (5) the end of the month following the fifth anniversary of the date disability benefits commenced, if such benefits began after the attainment of age 65, (6) when the total disability benefits paid equal 50% of the participant's total earnings for the entire period of employment for which service has been granted prior to the date disability benefits began to accrue, or (7) upon failure of the participant to provide an earnings verification necessary to determine continuance of benefits. If the disability was caused by an on-the-job accident, and the participant is granted workers' compensation or occupational disease payments from the employer or the State of Illinois, the limitation in clause (6) shall not be applicable.
Service and earnings credits under the State Employees' Retirement System of Illinois and the Teachers' Retirement System of the State of Illinois shall be considered in determining the employee's eligibility for, and the duration of disability benefits.
If, by law, a function of a governmental unit, as defined by Section 20-107 is transferred in whole or in part to an employer and an employee transfers employment from the governmental unit to such employer within 6 months after the transfer of this function, the pension credits in the governmental unit's retirement system which have been validated under Section 20-109, shall be treated the same as pension credits in this Section in determining an employee's eligibility for, and the duration of disability benefits.
40 ILCS 5/15-152