Liquid petrol isn't particularly explosive and quite hard to ignite (the reason why car engines require a fuel/air mixture at high pressure before the spark can ignite it), but petrol does vapour at room temperature and the vapour is extremely explosive. The best way to store petrol is in a sealed container, filling it as full as possible before sealing it. In this way very little vapour is given off by the petrol (so long as the container is well sealed) and thus it is not likely to explode in the event of something piercing the container (though once the container is pierced - no smoking *8-). (That's the easy option). A more involved option (though not necessarily better) is to prevent the fuel mixing with oxygen. A way to achieve this is to vacuum seal the container - the lack of oxygen in the container will prevent any kind of flammable reaction, even if vapour is present. Of course you could always just buy crude oil and carry that. Then all you need to do is distill it when you need it..... P.S Please note that plastic containers for petrol are not for long term storage. I'd recommend getting a metal can if you are going to have it for any length of time.