Title 49 of the US Code of Federal Regulations (49 CFR) contains all US regulations dealing with Transportation in the United States. The Title is organized into nine volumes, and the regulations it contains are authored by various components of the Departments of Transportation and Homeland Security. Most notably, 49 CFR contains the US Hazardous Material Regulations (HMR) in Parts 100-177.
Title 49 Transportation
Subtitle A—Office of the Secretary of Transportation