I turned out to a rollover a few years ago, where there was 6 G size oxy cylinders "hissing". The valves had cracked, but not sheared off. I stood them up so any forces were pointing down, and laid safe cylinders around them so they couldn't tip over towards the road, but instead fall over so the tops were facing the road (projecting away from the scene/ us, casualties)
None of the cylinders let go, but did hiss continuously for the 30mins or so I was on-scene.
FWIW, the cause of the incident was a 8x5 caged trailer behind a 4WD work truck, the drawbar of the trailer broke away from the body (doing 80 kph (50mph) and the rest of the trailer rolled and the load came out the top of the cage - the load was all cylinders of industrial gases (oxy, acet, LPG (propane), and maybe an argon or two)