The Southwest Regional Office, based in Houston, Texas, is comprised of personnel from the Office of Hazardous Materials Safety and the Office of Pipeline Safety. The offices are charged with overseeing the safe and secure movement of daily shipments of hazardous materials by all modes of transportation, as well as ensuring the safe, reliable, and environmentally sound operation so of the nation's pipeline infrastructure.

The area of responsibility for this region is listed above; however, the jurisdiction of PHMSA staff is nationwide and not limited to their regional area of responsibility.