The Hazardous Materials Regulations (HMR), managed by the Pipeline and Hazardous Materials Safety Administration (PHMSA), govern the transportation of hazardous materials in interstate, intrastate, and international commerce. The main goal of the HMR is to protect the public and professionals involved in the handling and transport of hazardous materials. To reduce risks, PHMSA establishes specific requirements for hazardous material shipments. The HMR are categorized into four general areas:

• Hazardous materials identification and classification;
• Hazard communication, such as the shipping papers, markings, labels, and placards used to communicate hazards of the materials to emergency responders, as well as to those who handle hazardous materials routinely;
• Packaging requirements; and
• Operational rules.

A basic understanding of the HMR is required for compliance with the regulations.