During training this past week using thunder launchers I stored my equipment in the truck bed as I normally do to move to a new location. I removed the gas cylinders from the launchers and stored them in the upright position. I placed the equipment in the enclosed bed of my truck. Whne I got to the next spot to train and I opened the bed of the truck I could smell the map gas. In just a few minutes I had lost half of a 4lb bottle of gas into the back of the truck. I am sure it was enough gas to kill a dog. Luckily I had let my dog ride in the cab with me. I am ordering Brass caps to seal the bottles. But on a hot day the bottles can still vent gas into the bed of the truck so my goal is to find some way to transport outside of the vehicle.