29 CFR 801.8 - Employment relationship.
(b) EPPA restrictions apply to State Employment Services, private employment placement agencies, job recruiting firms, and vocational trade schools with respect to persons who may be referred to potential employers. Such entities are not liable for EPPA violations, however, where the referrals are made to employers for whom no reason exists to know that the latter will perform polygraph testing of job applicants or otherwise violate the provisions of EPPA.
(c) EPPA prohibitions against discrimination apply to former employees of an employer. For example, an employee may quit rather than take a lie detector test. The employer cannot discriminate or threaten to discriminate in any manner against that person (such as by providing bad references in the future) because of that person's refusal to be tested, or because that person files a complaint, institutes a proceeding, testifies in a proceeding, or exercises any right under EPPA.