(a) With respect to employees of the state who are members of the state employees’ retirement system created by Act No. 240 of the Public Acts of 1943, as amended, the regents of the university of Michigan, the state board of agriculture, public school employees who are members of the retirement system created by chapter 1 of Act No. 136 of the Public Acts of 1945, as amended, the probate judges who are members of the probate judges’ retirement system created by Act No. 165 of the Public Acts of 1954, as amended, and the judges who are members of the judges’ retirement system created by Act No. 198 of the Public Acts of 1951, as amended, the governor is empowered to authorize a referendum upon the request of the respective boards administering the retirement systems for such coverage group. With respect to the employees of any political subdivision, including a school district of the first class whose employees are members of the retirement system created by chapter 2 of Act No. 136 of the Public Acts of 1945, as amended, he shall authorize a referendum only upon joint petition of the governing body of such political subdivision or school district of the first class together with the governing body of the retirement system in which such employees have membership. In lieu of the governing body of the retirement system in which such employees have membership and/or if there is no such retirement system governing body, there may be substituted as joint petitioner with the governing body of such political subdivision a petition signed by not less than 20% of the employees in positions under consideration for old-age and survivors insurance coverage.

     The referendum shall be conducted in accordance with the provisions of section 218 (d) (3) of title II of the social security act, by the retirement system governing body, or, if no such retirement system governing body, then by the governing body of the political subdivision under the supervision of the governor or any agency or individual designated by him on the question of whether service in positions covered by a retirement system established by the state or by a political subdivision thereof should be excluded from or included under an agreement under this act: Provided, That in the case of a retirement system that is part of the charter of the political subdivision, the plan shall be agreed to by action of the governing body of the political subdivision and by referendum of the employees as herein provided, before submission to the electorate.

     The notice of referendum required by section 218(d)(3)(c) of title II of the social security act to be given to employees shall be accompanied by, or shall, not less than 40 days prior to the referendum, be supplemented by a statement in such manner, form and detail as the agency or individual designated to supervise the referendum shall deem necessary and sufficient to inform the employees of the rights which will accrue to them and their dependents and survivors, and the liabilities to which they will be subject if their services are included under an agreement under this act. In case a 90 day period after notice of referendum shall lapse before changes in a retirement system shall have been enacted or approved as above provided, then the date of referendum shall be automatically extended to not less than 40 days after such enactment or adoption.

    (b) Upon receiving evidence satisfactory to him that, with respect to any such referendum, the conditions specified in section 218(d)(3) of title II of the social security act and the conditions specified in this act, as amended, have been met, the governor or an official delegated by him shall so certify to the secretary of health, education, and welfare.