Which federal agency is responsible for regulating hazardous materials transportation?

The Pipeline and Hazardous Materials Safety Administration (PHMSA) is the federal agency specifically tasked with regulating the transportation of hazardous materials. PHMSA operates under the Department of Transportation (DOT) and is responsible for ensuring the safe and secure transport of hazardous materials by various modes, including road, rail, air, and water.

This agency develops regulations and standards to protect the public and the environment from the risks associated with hazardous material transport. PHMSA also conducts research, provides guidance on compliance, and runs outreach programs to educate the industry and the public about safe practices for transporting dangerous goods.

The other agencies mentioned have different responsibilities; the Environmental Protection Agency (EPA) focuses on environmental protection, OSHA deals with workplace safety and health standards, and while the Department of Transportation oversees various aspects of transportation—including PHMSA's work—it is the PHMSA that specifically handles hazardous materials regulations. Thus, the correct answer reflects the specialized role of PHMSA in this context.