No person shall be employed as a firefighter for the city without having first applied for and having been accepted as a member of the firefighter's pension fund of the city. The city council hereby provides that it is a condition of employment with the fire department that all members of the fire department shall actively participate and become members of the firefighter's pension fund (municipalities 500,000 and under as provided in 40 ILCS 5/4-101 through 5/4-144). The failure of any member of the fire department to participate in said pension fund shall be grounds for cause for removal from his position as a member of the fire department. (Ord. 5438, 3-28-1990)