It is not an unlawful employment practice for an employer, employment agency or labor organization to observe the terms of a bona fide seniority system or any bona fide employee benefit plan such as a retirement, pension or insurance plan, which is not a subterfuge to evade the purposes of this chapter. However, except as otherwise provided by law, no such employee benefit plan shall excuse the failure to hire any individual and no such seniority system or employee benefit plan shall require the involuntary retirement of any individual 18 years of age or older because of the age of such individual.
ORS 659A.321