La. Public Officers and Employees § 42:1011
In order to extend on the broadest possible basis to employees of the state and its political subdivisions and to the dependents and survivors of said employees the basic protection accorded to other employees by the federal old age, survivors, disability insurance, and health insurance coverage embodied in the Social Security Act, as amended, an agreement or modification for coverage pursuant to Section 218(d)(3) executed after June 26, 1961, may be made retroactive to a date as early as the first day of the fifth calendar year before the year in which the agreement or modification is executed. An agreement or modification for coverage pursuant to Section 218(d)(6) and Section 218(d)(7) may be made retroactive to a date as early as January 1, 2003.
La. Public Officers and Employees § 42:1011