I recently purchased a few tanks used, and ended up with Luxfers dated 1982, 1988, and 1993 (got a really good price on them, so...) I know that there was a problem with the alloy used in some of the tanks from the 80's, but I can't find the exact date ranges anywhere. Does anyone know when the problem tanks started and ended production? If one (or two) of the tanks that I have fall in the date range, what would be the responsible course of action - to err on the side of caution and make wind chimes out of them (in which case I still got a good deal on the one or two remaining, so not a big loss) or to continue using them and cross my fingers that I don't end up being responsible for blowing half of my LDS apart if one of them unzips on them during fill?