Mich. Comp. Laws § 46.12e
Subject to the protecting local government retirement and benefits act, if an employee of a county department of a county that has adopted a retirement system providing for the payment of benefits in the event of a nonduty disability or nonduty death is transferred to the employ of this state because of a function of the department is transferred to this state, the transferred employee who does not withdraw his or her accumulated contributions from the county's retirement system, and who while employed by this state sustains nonduty total disability or nonduty death, must have the credited period of service while employed by this state added to the credited period of service with the county before the transfer for the purpose of determining eligibility for nonduty disability retirement pension or benefits or, for nonduty death benefits payable to the dependents of deceased employees under the plan adopted by the county. Subject to the protecting local government retirement and benefits act, all pension or retirement benefits of a transferred employee described in this section or his or her dependents must be based on the service credit and compensation earned while employed by the county. Subject to the protecting local government and retirement benefits act, the board of commissioners by ordinance may provide that all pension or retirement benefits of transferred employees or their dependents must be based on the highest 5 years of service credit and compensation earned while employed by either the county or this state.
MCL 46.12e