The U.S. Department of Transportation (DOT) is responsible for developing and issuing the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-185). These regulations govern the transportation of hazardous materials (hazmat) in interstate, intrastate, and foreign commerce. DOT carries out this responsibility through the Pipeline and Hazardous Materials Safety Administration (PHMSA). The primary goal of the HMR is to ensure the safety of the public and those who prepare, offer, and transport hazmat.
The Code of Federal Regulations (CFR) are rules published in the Federal Register by Executive departments and agencies of the Federal Government and have the force of the law. The 49 CFR, Parts 100-185, contains the current HMR under Chapter I - Pipeline and Hazardous Materials Safety Administration, U.S. Department of Transportation.