The U.S. Department of Transportation, Title 49 CFR, governs and is the regulatory authority for the transportation of all hazardous materials in commerce, on public highways and waterways and in the airspace of the United States. This includes the regulatory guidance of transportation of such materials by private aircraft, air taxi/charter, and airline passengers and all cargo operations under FAR Parts 91, 121, and 135.The transportation of any defined hazardous material by private general aviation aircraft, while not totally prohibited (note that many materials are, in fact, prohibited), does carry certain risks and should not be considered, unless absolutely necessary.