Sec. 2. As used in this chapter, "employer" means:
(1) a municipality that established a 1925 or 1953 fund or that participates in the 1977 fund under section 3 or 18 of this chapter;
(2) a unit that established a 1937 fund or that participates in the 1977 fund under section 3 or 18 of this chapter;
(3) a consolidated city that consolidated the fire departments of units that:
(A) established a 1937 fund; or
(B) participated in the 1977 fund;
before the units' consolidation into the fire department of a consolidated city established by IC 36-3-1-6.1;
(4) a consolidated city that establishes a consolidated law enforcement department under IC 36-3-1-5.1;
(5) an airport authority that participates in the 1977 fund under section 3 of this chapter; or
(6) a school corporation or charter school that participates in the 1977 fund under section 3 of this chapter.