Thanks hankaye and notanlines.
I have removed the tank from the garage to outside.
I am wondering about where it was leaking from. The last fill was done at a campground where they used the screw on the side of the valve to determine when it was filled, loosened it and when they saw propane escaping they stopped the pump and tightened the screw. That seemed to be where the gas was leaking yesterday so I tightened it a little more and it stopped hissing at me, but I did smell propane again later, I think they may have messed up the threads or something.