RCW 41.24.050: Emergency medical technicians or first aid vehicle operators—Restriction on retirement system membership.

No person serving as an emergency medical technician or first aid vehicle operator under chapter 18.73 RCW shall be permitted to join the law enforcement officers' and firefighters' retirement system solely on the basis of such service. In no case shall the membership of any fire department coming under the provisions of this chapter be limited to less than fifteen firefighters.