(a) Any municipality except a housing authority, which is governed by subsection (b) of this section or a regional workforce development board established under § 31-3k, which is governed by § 7-427a, may, by resolution passed by its legislative body and subject to such referendum as may be hereinafter provided, accept this part as to any department or departments of such municipality as may be designated therein, including elective officers if so specified, free public libraries which receive part or all of their income from municipal appropriation, and the redevelopment agency of such municipality whether or not such municipality is a member of the system, as defined in § 7-452, but such acceptance shall not repeal, amend or replace, or affect the continuance of, any pension system established in such municipality by or under the authority of any special act and all such special acts shall remain in full force and effect until repealed or amended by the General Assembly or as provided by chapter 99. The acceptance of this part as to any department or departments of a municipality shall not affect the right of such municipality to accept it in the future as to any other department or departments. In any municipality other than a district department of health, housing authority, flood commission or authority, regional council of governments or supervision district board of education, such resolution shall not take effect until it has been approved by a majority of the electors of the municipality voting thereon at the next regular election or meeting or at a special election or meeting called for the purpose. The effective date of participation shall be at least ninety days subsequent to the receipt by the Retirement Commission of the certified copy of such resolution. The Retirement Commission shall furnish to any municipality contemplating acceptance of this part, at the expense of such municipality, an estimate of the probable cost to such municipality of such acceptance as to any department or departments thereof.

(b) Unless the board of commissioners of a housing authority votes against such participation, employees of housing authorities who are eligible under § 7-425 and who are not members of the Municipal Employees’ Retirement Fund B shall become members thereof on July 1, 1972, and membership in any other retirement fund, except the federal old age and survivors insurance, shall terminate on said date. Housing authorities whose employees are enrolled on or before May 21, 1971, in any other retirement system shall arrange for termination of such system on July 1, 1972, which arrangements shall include provision that the rights of members who retired prior to July 1, 1972, under such system shall not be affected and provision that any refunds of employee contributions made to such other retirement system shall be transferred to the Municipal Employees’ Retirement Fund B and the appropriate amount credited to the account of each transferring employee’s benefit.