29 C.F.R. § 1982.102
(a) National Transit Systems Security Act.
(1) A public transportation agency, contractor, or subcontractor of such agency, or officer or employee of such agency, shall not discharge, demote, suspend, reprimand, or in any other way retaliate against, including but not limited to intimidating, threatening, restraining, coercing, blacklisting, or disciplining, an employee if such retaliation is due, in whole or in part, to the employee's lawful, good faith act done, or perceived by the employer to have been done or about to be done—
(i) To provide information, directly cause information to be provided, or otherwise directly assist in any investigation regarding any conduct which the employee reasonably believes constitutes a violation of any Federal law, rule, or regulation relating to public transportation safety or security, or fraud, waste, or abuse of Federal grants or other public funds intended to be used for public transportation safety or security, if the information or assistance is provided to or an investigation stemming from the provided information is conducted by—
(2)
(i) A public transportation agency, contractor, or subcontractor of such agency, or officer or employee of such agency, shall not discharge, demote, suspend, reprimand, or in any other way retaliate against, including but not limited to intimidating, threatening, restraining, coercing, blacklisting, or disciplining, an employee for—
(ii) A refusal is protected under paragraph (a)(2)(i)(B) and (C) of this section if—
(B) A reasonable individual in the circumstances then confronting the employee would conclude that—
(1) The hazardous condition presents an imminent danger of death or serious injury; and
(2) The urgency of the situation does not allow sufficient time to eliminate the danger without such refusal; and
(b) Federal Railroad Safety Act.
(1) A railroad carrier engaged in interstate or foreign commerce, a contractor or a subcontractor of such a railroad carrier, or an officer or employee of such a railroad carrier, may not discharge, demote, suspend, reprimand, or in any other way retaliate against, including but not limited to intimidating, threatening, restraining, coercing, blacklisting, or disciplining, an employee if such retaliation is due, in whole or in part, to the employee's lawful, good faith act done, or perceived by the employer to have been done or about to be done—
(i) To provide information, directly cause information to be provided, or otherwise directly assist in any investigation regarding any conduct which the employee reasonably believes constitutes a violation of any Federal law, rule, or regulation relating to railroad safety or security, or gross fraud, waste, or abuse of Federal grants or other public funds intended to be used for railroad safety or security, if the information or assistance is provided to or an investigation stemming from the provided information is conducted by—
(2)
(i) A railroad carrier engaged in interstate or foreign commerce, or an officer or employee of such a railroad carrier, shall not discharge, demote, suspend, reprimand, or in any other way retaliate against, including but not limited to intimidating, threatening, restraining, coercing, blacklisting, or disciplining, an employee for—
(ii) A refusal is protected under paragraph (b)(2)(i)(B) and (C) of this section if—
(B) A reasonable individual in the circumstances then confronting the employee would conclude that—
(1) The hazardous condition presents an imminent danger of death or serious injury; and
(2) The urgency of the situation does not allow sufficient time to eliminate the danger without such refusal; and
(3) A railroad carrier or person covered under this section may not:
(ii) Discipline, or threaten discipline to, an employee for requesting medical or first aid treatment, or for following orders or a treatment plan of a treating physician, except that—