Good point. The odds are astronomical until you look at how few people man the fill-stations of this country. There are only about 2000 commercial fill stations in the US. I would guess that less than 10% do over 80% of the fills a year. In the last four or five years some have exploded and who knows how many have been discovered leaking or cracked. Annual inspections catch most of these defective tanks before they actually explode, but in so doing, they make the tanks look safer (statistically) than they really are. The odds get much worse when you consider that only about 400 fill stations fill approximately 80% of the scuba tanks in this country. Now consider how many other people may be in the vicinity when the tanks are filled.Hey B2B,
If it was my tank. I would get it eddy current tested and vis'd. If it passes, I would fill it and dive it. 13 tanks out of millions? I think you'd have better odds of getting bit by a shark and getting hit by lighting in the same day. But that's me. I have a pretty high comfort level. If you have the vis and eddy current testing done every year, you'll be fine. If the tanks were "that dangerous" they would have all been recalled and we wouldn't be having this discussion.
However, keeping a questionable piece of gear that has the potential to release a force of 1,300,000 foot pounds may not be the most intelligent move a person could make. Maybe this is why very few active and knowledgable shops will fill the faulty alloy.
