Can you transport 1 tank of propane for a forklift without a hazmat permit?

As far as licencing goes, you can transport up to 1000 lbs. of certain hazmat classes without requiring a hazmat endorsement, so the one propane tank is legal - look at how many RVers have them on the back of their RVs. If you're operating as a third party carrier, it does get a little more complicated, however. If that tank is attached to the forklift as you transport it, it's considered part of the vehicle. However, if the tank is placed separately from a unit it's being transported with, then it requires the carrier to have hazmat insurance (whether or not the load requires a hazmat endorsement).