Which governmental agency regulates the transportation of hazardous materials?

The U.S. Department of Transportation (DOT) is the governmental agency responsible for regulating the transportation of hazardous materials. This includes establishing regulations that ensure the safe and efficient transport of materials that could pose a risk to health, safety, or the environment. The DOT sets guidelines for labeling, packaging, and transporting hazardous materials across all modes of transportation, including aviation, rail, and road.

The other agencies listed do have roles related to safety and environmental protection but do not specifically focus on the transportation of hazardous materials. The Department of Environmental Protection mainly oversees environmental conservation and pollution control, while the Federal Aviation Administration regulates civil aviation, not ground transportation. The National Highway Traffic Safety Administration is concerned with road safety but does not directly manage hazardous materials transport. Hence, the U.S. Department of Transportation is the correct choice for this question, as its primary function includes the oversight and management of hazardous material transportation regulations.