Seriph - as some guys already mentioned, oil is extreamly flamable...However, if you try to light, for example, oil that is spiled out on the ground on fire you will have to work on that for quite a while. Not easy..The problem comes when oil is under hight pressure and "pushed" out through a cracked "tube"...Then the oil will be sprayed out in very fine drops and perfectly mixed with air...Now you have oxygen and a flamable fluid and all you need now is.....a source of heat...that could be ,as mentioned before, hot breaks or a fire......After two years with the Airport Fire depart. I know what I'm talking about.