I went to my local ACE hardware store last Sunday to get a new 20lb propane tank for our gas grill. I left myself only ~15 min. to closing. When I got it home and attempted to install it and fire-up the grill, I found it IMPOSSIBLE to open the tank's valve by hand. Thank God for my Biomedical technician training which ALWAYS emphasizes safety. I therefor WILL NOT attempt it with tools. The tank valve is over-torqued and thereby damaged. This situation was conspicuously absent from any safety info I've found, at least in specific terms. I think it should be included. As for this tank, I'm getting my money back, getting the name of their supplier and avoiding same. See links to Propane tank safety sources below.