Occasionally this comes up and at least 3 people are always, "well I've never seen this how often does this happen?"
Answer? I don't know but I'd guess "it only takes once." A friend of mine recently gave me a typical cheap china import that had rusted through the tank. It had NOT exploded, but had rusted through and leaked and he caught it and realized what was going on
It's not just the compressor you need to be concern about, but also the old tools, hose and attachments. Any compress air bottles or tanks can and should be hydro tested yearly or as designated, as fire extinguishers, dive tanks and other types of holding tanks. I have had hoses (oil soak or pulled from fittings) and seals in tools blow and it is not a pleasure. We have been lucky and I and others are thankful for you bringing this mishap to our attention. Never would of thought a small air tank would blow as yours did.