49 CFR §1584.3

In addition to the terms in §§ 1500.3, 1500.5, and 1503.202 of subchapter A and § 1570.3 of subchapter D of this chapter, the following term applies to this part. Security-sensitive employee means an employee whose responsibilities for the owner/operator include one or more of the security-sensitive job functions identified in Appendix B to this part where the security-sensitive function is performed in the United States or in direct support of the common carriage of persons or property between a place in the United States and any place outside of the United States.