I believe major damage now has a flame thrower, if your tank got slightly punctured and stared leaking fuel it would be very easy for a fire to be caused, the floor is made of wood so it could get very serious. It could even be ignited from sparks from a spinning weapon. You've also got the exhaust gases which could cause issues if there isn't good ventilation but I guess you've already got the co2 from pneumatics so not such a big issue.