29 CFR §801.20

1. (a)Section 8(a) (1) of the Act provides that the limited exemption in section 7(d) of the Act and § 801.12 of this part for ongoing investigations shall not apply if an employer discharges, disciplines, denies employment or promotion or otherwise discriminates in any manner against a current employee based upon the analysis of a polygraph test chart or the refusal to take a polygraph test, without additional supporting evidence.
2. (b)“Additional supporting evidence”, for purposes of section 8(a) of the Act, includes, but is not limited to, the following:
   1. (1)
      1. (i)Evidence indicating that the employee had access to the missing or damaged property that is the subject of an ongoing investigation; and
      2. (ii)Evidence leading to the employer's reasonable suspicion that the employee was involved in the incident or activity under investigation; or
   2. (2)Admissions or statements made by an employee before, during or following a polygraph examination.
3. (c)Analysis of a polygraph test chart or refusal to take a polygraph test may not serve as a basis for adverse employment action, even with additional supporting evidence, unless the employer observes all the requirements of sections 7(d) and 8(b) of the Act, as described in §§ 801.12, 801.22, 801.23, 801.24, and 801.25 of this part.