Which agency designates materials as hazardous for transportation?

The U.S. Department of Transportation (DOT) is the agency responsible for designating materials as hazardous for transportation. This designation is crucial because it informs carriers and the public about the potential risks associated with transporting such materials. The DOT develops regulations that govern the classification, packaging, labeling, and placarding of hazardous materials to ensure safe transportation and handling.

The DOT's Hazardous Materials Regulations (HMR) provide guidelines that help prevent accidents and incidents during transport, ensuring the safety of both the environment and public health. These regulations apply to all modes of transportation, including road, rail, air, and waterways, making the DOT a central authority in this area.

Other agencies like the Environmental Protection Agency (EPA) and the Occupational Safety and Health Administration (OSHA) focus primarily on different aspects of environmental protection and workplace safety, respectively, rather than specifically addressing the designation of hazardous materials for transportation. The Federal Aviation Administration (FAA) regulates civil aviation and the safety of air travel but does not handle the broader aspects of hazardous materials regulation. Thus, the DOT specifically focuses on the transportation of hazardous materials, making it the correct choice.