What regulatory body mandates the weight limit marking for vehicles carrying LP gas?

The Department of Transportation (DOT) is the regulatory body responsible for establishing and enforcing safety regulations for the transportation of hazardous materials, including liquefied petroleum (LP) gas. One of the critical safety measures is the requirement for weight limit markings on vehicles that transport these materials. These markings help ensure that vehicles are not overloaded, which can compromise safety during transport. Overloading can lead to accidents, spills, and other hazardous situations, making the weight limit marking essential for public safety and compliance with federal regulations.

In contrast, the Environmental Protection Agency (EPA) focuses on environmental protection and does not directly regulate the transport weight limits for vehicles carrying hazardous materials. The Occupational Safety and Health Administration (OSHA) is concerned with workplace safety and health but does not regulate transportation of LP gas. The National Fire Protection Association (NFPA) establishes codes and standards for fire safety but also does not dictate weight limit markings on transport vehicles. Therefore, DOT is the correct choice as it oversees safety regulations related to transportation logistics involving LP gas.