Nonapplication and exemption

§ 21102. Nonapplication and exemption (a) General.—This chapter does not apply to a situation involving any of the following: (1) a casualty. (2) an unavoidable accident. (3) an act of God. (4) a delay resulting from a cause unknown and unforeseeable to a railroad carrier or its officer or agent in charge of the employee when the employee left a terminal. (b) Exemption.—The Secretary of Transportation may exempt a railroad carrier having not more than 15 employees covered by this chapter from the limitations imposed by this chapter. The Secretary may allow the exemption after a full hearing, for good cause shown, and on deciding that the exemption is in the public interest and will not affect safety adversely. The exemption shall be for a specific period of time and is subject to review at least annually. The exemption may not authorize a carrier to require or allow its employees to be on duty more than a total of 16 hours in a 24-hour period.