Which division of the U.S. Department of Transportation regulates hazardous materials?

The Pipeline and Hazardous Materials Safety Administration (PHMSA) is the division of the U.S. Department of Transportation that specifically focuses on the regulation of hazardous materials. This agency is responsible for ensuring the safe and efficient transportation of hazardous materials by land, water, and air. PHMSA develops regulations that are intended to prevent accidents and incidents during the transport of these materials, which can pose risks to health, safety, and the environment.

PHMSA's role includes managing the enforcement of regulations that govern the packaging, labeling, and transportation methods for hazardous materials, as well as providing guidance and support to various stakeholders within the transportation sector. This regulatory framework is crucial for maintaining safety standards and protecting the public and the environment from potential hazards associated with the transport of dangerous goods.

Other agencies referenced in the options have different primary responsibilities: the National Highway Traffic Safety Administration (NHTSA) focuses on road safety and vehicle regulations; the Federal Aviation Administration (FAA) oversees civil aviation safety; and the Federal Railroad Administration (FRA) regulates the railroad industry. Each of these agencies plays an important role in transportation safety, but they do not have the specific mandate to regulate hazardous materials like PHMSA does.