Which entity regulates the usage of LPG in transport units in Texas?

In Texas, the Railroad Commission of Texas is primarily responsible for regulating the usage of liquefied petroleum gas (LPG) in transport units. This commission has jurisdiction over the safety standards and regulations related to the transportation, storage, and use of LPG, ensuring that practices comply with both state laws and federal regulations. The Railroad Commission's oversight includes enforcing safety measures and operational practices that safeguard public health and the environment concerning LPG use.

The other entities listed have different roles: The Environmental Protection Agency focuses on environmental protection laws, the Federal Aviation Administration governs aviation and air transport, and the Department of Transportation oversees transportation infrastructure and policy but does not specifically regulate LPG use in transport units at the state level in Texas. Thus, the Railroad Commission of Texas is the correct choice for those regulations.