In my HAZMAT classes, I always ask the question: A container of diesel fuel is at its flash point, and a gasoline container is at its flash point – an ignition source is present within the container – which container ignites first? Nearly 100% of the students will say the gasoline container and nearly 100% are WRONG! The reason: Diesel fuel has an LEL of around 0.5%, and Gasoline has an LEL of around 1.5%, meaning that the LEL will be achieved in the diesel container MUCH FASTER. The ONLY thing diesel fuel has that makes it safer is a HIGH flash point; however, when we expose diesel fuel to cutting torches and grinders, we can spread the heat via conduction to the diesel fuel, raising the temp of the solution. Thus we create a flammable atmosphere in short order! In fact, since most workers have some level of respect for gasoline and very little for diesel fuel, we see more diesel fuel tank explosions than we do gasoline. Case in point…
Two workers at an environmental engineering company were injured after a diesel fuel tank explosion. The worker was injured when the diesel tank he was working on exploded, throwing him to the ground. Two workers, 29 and 31, were working on the tank when it exploded. The worker that was cutting the diesel tank with a saw suffered burns to the right side of his body. The other worker was treated at the scene for minor injuries. The injured worker suffered first- and second-degree burns to his arms and torso from the fire and explosion at the underground fuel tanks on the site. The explosion sent flames 30 feet into the air, witnesses said. The worker was thrown 5 feet. OSHA is investigating.