Cal. Gov. Code § 31479.3
"Public service" also means service in the merchant marine of the United States during the period of December 7, 1941, through August 15, 1945, whether or not the employee received compensation from the United States Government and with respect to which he or she is not entitled to receive credit in any retirement system supported wholly or in part by public funds after he or she became a member of this system. This section shall apply to both members and retired members of a county retirement association subject to this chapter. Both members and retired members may purchase public service credit pursuant to Sections 31641.1 and 31641.2. For a retired member the additional pension amount accruing because of any public service credit purchased shall be computed as though the service had been credited on the effective date of retirement and increased by any cost-of-living increases which may have been granted since the effective date of retirement and shall begin as of the first of the month following either the date of receipt of the retired member's election to purchase the credit pursuant to Section 31641.1 or the date of receipt of the full cost of the purchase computed pursuant to Section 31641.2 whichever is later.
This section shall not be operative in any county until the board of supervisors shall, by resolution adopted by a majority vote, make this section applicable in the county.
Ca. Gov. Code § 31479.3