Wash. Rev. Code § 49.44.090
It shall be an unfair practice:
Nothing contained in this section or in RCW 49.60.180 as to age shall be construed to prevent the termination of the employment of any person who is physically unable to perform his or her duties or to affect the retirement policy or system of any employer where such policy or system is not merely a subterfuge to evade the purposes of this section; nor shall anything in this section or in RCW 49.60.180 be deemed to preclude the varying of insurance coverages according to an employee's age; nor shall this section be construed as applying to any state, county, or city law enforcement agencies, or as superseding any law fixing or authorizing the establishment of reasonable minimum or maximum age limits with respect to candidates for certain positions in public employment which are of such a nature as to require extraordinary physical effort, or which for other reasons warrant consideration of age factors.
RCW 49.44.090
Severability-1993 c 510: See note following RCW 49.60.010.
Element of age not to affect apprenticeship agreements: RCW 49.04.910.
Unfair practices, discrimination because of age: RCW 49.60.180 through 49.60.205.