California Public Resources Code Section 4142

(a) The department may, with the approval of the Department of General Services, enter into a cooperative agreement upon the terms and under the conditions as it deems wise, for the purpose of preventing and suppressing forest fires or other fires in any lands within any county, city, or district which makes an appropriation for that purpose. (b) When the state assumes personnel from a county, city, or district, an actuarially determined benefit factor shall be included as a cost in the cooperative agreement, including renewals of the agreement, for any county, city, or district which elects to allow the completed years an employee worked at that county, city, or district, or a lesser number of completed years specified by the local agency, to be credited towards the vesting period for state postretirement health benefits. The department shall certify the completed years of county, city, or district service to be credited to an employee to the Board of Administration Public Employees` Retirement System at the time of separation for retirement. The actuarially determined benefit factor shall be accepted as sufficient by the Department of Forestry and Fire Protection, upon review by the Department of Finance, to fully compensate the state for the postretirement health benefit costs of those employees. The postretirement health benefit costs charged under this subdivision may be paid in periodic installments at the discretion of the department. If the costs are paid in installments, the payment of the postretirement health benefit costs for years credited for nonstate service shall be a continuing obligation of any county, city, or district which made that election, regardless of whether or not the cooperative agreement continues or is renewed, and regardless of whether or not the employees continue in state service.