we used to drill holes in it here in Canada , without owners permission (70s/80s ) now we cant without owners permission . recently I was called by a lds and told they had a failed cylinder so I went to pick it up ( I use them for teaching vip /fill station courses ) and I almost died when I saw the date . it was LESS THAN 4 YEARS OLD ! the store manager said it failed vis eddy ..so I took the tank and I eddied it , passed then I had 2 hydro facilities eddy it ,(1 facility had 2 different tech's check it ) every one passed the tank with no problem so its still a opinion on the tests you just hope you get someone who's competent .....people forget /complacent with the explosive power they are dealing with