Tennessee Code Title 8. Public Officers and Employees § 8-35-219

(a) Notwithstanding §§ 8-35-103 and 8-35-217 to the contrary, any current or future employer which participates in the retirement system pursuant to this part shall have the option to exclude its part-time employees from membership in the retirement system by passage of a resolution of its chief governing body; provided, that any employee of such employer participating in the retirement system by virtue of part-time service shall continue to be eligible for membership in the retirement system.

(b) The chief legislative body of any employer participating in the retirement system pursuant to this part may elect at a later date to extend retirement coverage to its part-time employees by passage of a resolution authorizing such coverage and accepting the liability therefor; provided, that any such resolution shall be irrevocable and the employer shall not later be permitted to exclude part-time employees under this section.