(A) For the purposes of Chapter 145. of the Revised Code, this rule, and rule 145-2-17 of the Administrative Code:

(1) "Firefighter" means a person who:

(a) Is employed as a firefighter by a public employer; and

(b) Is hired or appointed, controlled and paid earnable salary and otherwise treated as an employee by the public employer.

(2) "Volunteer firefighter" means a person who:

(a) Is an employee of a private fire company or association;

(b) Performs service as a firefighter for no compensation or for an honorarium;

(c) Is an employee of a nonprofit fire company or association; or

(d) Is not a firefighter pursuant to paragraph (A)(1) of this rule.

(B)

(1) Except as otherwise provided by law, effective May 1, 1991, a firefighter shall be a member of the retirement system subject to all the rights and obligations of Chapter 145. of the Revised Code.

(2) Notwithstanding paragraph (B)(1) of this rule, a firefighter employed before May 1, 1991, shall be a member of the retirement system unless an exemption from membership on a form approved by the public employees retirement board is filed on or before May 31, 1991.

(3) Once filed an approved exemption is valid pursuant to the limitations in section 145.03 of the Revised Code or through June 29, 1991, whichever is later.

(C) Effective May 1, 1991, a volunteer firefighter is not a public employee and shall not be a member of the retirement system.

(D) A firefighter employed before May 1, 1991, who is or becomes a member on May 1, 1991 may purchase the firefighter service as described in rule 145-2-17 of the Administrative Code.