A friend at church told me about a problem with diesel fuel. I don't know exactly when this happened, but I think it was in the last week or two. Apparently my friend's brother put a fuel container in the back of his pickup truck and went to get some fuel. He did not want to bother getting the container out of the truck so he filled it up with the container sitting ungrounded in the truck bed. Not a smart move. He's lucky he wasn't filling up with gasoline.
Something set off an explosion while the tank was filling up. The fuel container launched into the air and took out a chunk of the awning over the pump at the gas station. Thankfully, the man's brother was not injured. Diesel is apparently less volatile than gasoline, which is a good thing in this situation.
I'd always heard that it was a bad idea to fill a fuel container that wasn't sitting directly on the ground, but this is the first time I've actually heard of a problem from an ungrounded tank.

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