There is a defective valve in tank ...
Home Depot pulled all the 400gr canisters off the shelves and will not sell them.

http://www.mapcylinderrecall.com/

New bottles manufactured after January 15, 2012 will have a black diamond on top of bottle signifying that it has new style cutoff valve.

These are now on the shelves again the black diamond is so tiny it is hard to see at 1st.Make sure your canister has one.

The 1st I heard of it was late January when I went to buy gas for a beginning class there were no map gas canisters for sale at Home Depot and the only recall in the internet was from the Australian Government. http://www.recalls.gov.au/content/in...itemId/1009686
Please make sure your canisters are not the old ones. Look for the tiny black diamond it is on the top and is about 3-4mm these are the ones they have corrected the problem on.
Just want to make sure everyone knows please be safe.
Sam
I posted in members only and just now saw that I thought I had done it here.