US DOT Hazardous Materials Regulations (49 CFR Parts 171 to 180) 172.800-804: Security plans: required for listed shipments, with risk assessment, personnel security, unauthorised access and en route security components, written, reviewed annually, with training and records (172.800 to 172.804)

Each person who offers for transportation or transports any of the 172.800(b) materials (for example large bulk quantities of hazardous materials above 3,000 kg or 3,000 L, Division 1.1 to 1.3 explosives over set quantities, materials poisonous by inhalation, select agents, highway route controlled quantities of Class 7, more than 1 kg of certain Division 1.4 or 1.5 explosives, uranium hexafluoride, and others) must develop and adhere to a written security plan based on an assessment of transportation security risks. The plan must include personnel security measures (confirming information from job applicants with access to the materials, within the limits of applicable law), measures to address unauthorised access to the materials or the conveyances being prepared for transport, and en route security measures, and must identify the senior management official responsible and the duties of each position. The plan must be in writing, retained while in effect, available to DOT, reviewed at least annually and revised when circumstances change, with affected employees trained in-depth and copies of the plan shared only as needed. Rail carriers of security-sensitive materials have additional 172.820 obligations.