Here in California in the BLM and NF, it is a $300 fine per can (if it has gasoline in it) if it is not CARB approved. The old steel cans are a no no. Most plastic cans do not have the CARB cert as well. I carry Rotopax now. At first, I did not like them simply because I "had to comply". Now I have found the mounts useful for a variety of uses. Long trips or when gas is hard to get, I carry two 3gl cans, on easier day or weekend trips, I carry one 2gl gas and one 2gl distilled water. I also have extended mounts to carry two 2gl on the same mount if needed. Rotopax makes a first aid kit and tool kit in the same profile as the 2gl cans. Very versatile. They have two downsides, 1) gotta do it in Ca. 2) pricey $$