29 U.S. Code § 2007 - Restrictions on use of exemptions
Except as provided in paragraph (2), the exemption under subsection (d) of section 2006 of this title shall not apply if an employee is discharged, disciplined, denied employment or promotion, or otherwise discriminated against in any manner on the basis of the analysis of a polygraph test chart or the refusal to take a polygraph test, without additional supporting evidence. The evidence required by such subsection may serve as additional supporting evidence.
In the case of an exemption described in subsection (e) or (f) of such section, the exemption shall not apply if the results of an analysis of a polygraph test chart are used, or the refusal to take a polygraph test is used, as the sole basis upon which an adverse employment action described in paragraph (1) is taken against an employee or prospective employee.
During the actual testing phase, the examiner does not ask such examinee any question relevant during the test that was not presented in writing for review to such examinee before the test.