All of the following are true of portable tanks EXCEPT:

The glossary at the end of this section gives the meaning of the word "bulk." Cargo tanks are bulk packaging permanently attached to a vehicle. Cargo tanks remain on the vehicle when you load and unload them. Portable tanks are bulk containers not permanently attached to a vehicle.
The product is loaded or unloaded while the portable tanks are off the vehicle. Portable tanks are then put on a vehicle for transportation. There are many types of cargo tanks in use. The most common cargo tanks are MC406 for liquids and MC331 for gases.