Are certain poisonous gases permitted on passenger-carrying vehicles?

The correct understanding is that certain poisonous gases are strictly forbidden on passenger-carrying vehicles. This regulation is rooted in safety concerns, as poisonous gases can pose significant health risks to passengers and crew in case of leaks or exposure. Passenger safety is paramount, and transporting substances that could endanger individuals is not allowed under hazardous materials regulations.

Other options may suggest limited allowances or conditions under which poisonous gases might be transported, but these conditions do not align with established guidelines for passenger transport. There is no provision that permits their transport under any conditions due to the inherent dangers associated with these materials. This underscores the commitment to ensuring a safe travel environment for all passengers.