Section 18. Notwithstanding the provisions of any general or special law to the contrary, an abolished county's employees who retired on or before the transfer date, and such abolished county's inactive members, shall be members of the regional retirement system, which shall pay the cost of benefits to such retired county employees and inactive members and their survivors. Said system shall be responsible for the accrued pension liability attributable to the service of such retirees and inactive members.

The employees of an abolished county who become state employees pursuant to the this chapter or any prior or subsequent act abolishing any county, shall become members of the state retirement system, and notwithstanding the provisions of any general or special law to the contrary including, but not limited to, paragraph (c) of subdivision 8 of section 3 of chapter 32, said system shall be responsible for all liability attributable to the service of such employees. Said liabilities attributable to the service of such employees shall be recoverable by the commonwealth pursuant to the terms of section 8.

Notwithstanding the provisions of this section to the contrary, the employees of the Essex Independent Agricultural and Technical Institute shall be members of the Essex Regional Retirement System. Said system shall retain all liability attributable to such employees for creditable service earned as employees of Essex County. The Essex Independent Agricultural and Technical Institute shall be a member unit of said regional system and shall make any payments required pursuant to chapter 32. Should said Essex Independent Agricultural and Technical Institute be abolished, the successor agency, or in the absence of a successor agency, the commonwealth, shall become responsible for any unfunded liability attributable to employees of said institute.

The accumulated deductions and employer contribution, including interest, credited to the accounts of members of an abolished county's retirement system who become members of the state retirement system pursuant to this chapter or any prior or subsequent act abolishing any county shall be transferred from such abolished county's retirement system and credited to such members' accounts in the state retirement system. The sum of the accumulated deductions, employer contributions and interest shall be known as the transfer assets. The transfer assets shall be determined by first assigning system assets to retiree and inactive liability, then assigning any remaining system assets to active employee liability, then determining the funded ratio of active employees to determine an amount of assets to transfer that will maintain the funded ratio of active employees in the regional retirement system after the transfer at a level that is not less than the funded ratio prior to the transfer. In no event shall an amount less than the annuity savings fund of the transferred members be transferred; provided, however, that if the transfer assets are less than the total of the annuity savings fund to be transferred, the secretary of administration and finance shall include the difference, which shall be known as the regional retirement system transfer deficit, as a liability in the calculation required pursuant to section 8.

Any calculations to be determined pursuant to this section and section 8 shall be performed by the actuary that performed, and shall be based on the assumptions used, in the most recent valuation of a county retirement system subject to review and approval by the actuary at the public employee retirement administration commission; provided, however, that all funds subject to transfer shall be transferred within 90 days of approval by the public employee retirement administration commission. All transfers made pursuant to this section shall include interest at the interest rate used in the most recent actuarial valuation of the county retirement system from the date of abolition until the date said funds are transferred.

Cities, towns, districts and other governmental units belonging to an abolished county's retirement system shall remain members of such retirement system.