Okla. Stat. tit. 25, § 1303

It is a discriminatory practice for an employment agency to fail or refuse to refer for employment, or otherwise to discriminate against, an individual because of race, color, religion, sex, national origin, age, genetic information or disability, unless the agency can demonstrate that accommodation for the disability would impose an undue hardship on the operation of the business of such agency, or to classify or refer for employment an individual on the basis of race, color, religion, sex, national origin, age, genetic information or disability, unless the agency can demonstrate that accommodation for the disability would impose an undue hardship on the operation of the business of such agency.