Posted By Ian Waldram Lots of hazards, but some depend on what kind of gas - flammable, toxic, oxygen or just inert? General rule is that cylinders should be in a well-ventilated space, so any leaks can disperse. Typically they are stored in the open, if there are security concerns a locked cage is an option. In all cases, if there's an external fire, the cylinder loses strength as it heats up and, unless it's cooled, will eventually fail suddenly due to internal pressure - very hazardous as, in addition to smaller bits flying, the expanding gas can set the cylinder off like a small rocket. Thus cylinders in an internal room don't make the Fire Brigade happy, even worse if there's no sign on the door to warn of the hazard. If the contents are toxic (e.g. Chlorine) or flammable (e.g. Acetylene, Propane), the fire hazard is worse! Also if these leak inside the room, there's a severe risk to anyone entering. Even a 'safe' gas like CO2 or Nitrogen will displace air if it leaks, so the person may be asphyxiated - not so common in a room, but a well-known hazard in confined spaces with no ventilation at all (so gas bottles are never taken in, and supply hoses are removed at work-breaks, in case of leaks). Oxygen might seem safer, but in fact more O2 in the atmosphere makes things easier to ignite, and fires burn fiercely - even the hairs on your skin can 'flash' instead of just singeing. Even an 'empty' cylinder has all these hazards to a lesser degree, so should also be stored outside. HSE webpage should provide basic advice on how to store gas cylinders safely, including use of a fire-resisting, well-ventilated room if that's really needed. Also British Compressed Gases Association (BGCA) provide lots of detailed safety advice, covering both storage and use. Hope this gives you a start on the risk assessment - but don't wait too long completing the paperwork before checking with the stadium operator whether they understand what they are doing - your posting reads as if they may not, if so alerting them is fully justified!

Posted By steve e ashton Matt - you have not given us enough information to comment. We need to know: what were the gases? what size cylinders? How many cylinders? what for? were they in use or in store, or empty? where does unlocked door lead from? How often is the door used? What (if any) detectors and/or control systems / alarms were in place? What if any ventilation arrangements? Any signs or notices on door? etc etc etc An unlocked door leading from a secure bar servery area into the cellar where four small CO2 cylinders are chained, stored and used is probably ok. The same door leading from a public area into a room with four large hydrogen / propane / acetylene cylinders that have not been used in living memory - is almost certainly not. As part of your MSc studies, you will learn to identify (and record if significant) the various relevant risk factors and make the assessment or 'risk rating' yourself. In the meantime - either provide more detail, or ask your tutor for advice! Good luck with your studies. Steve