trying to make the connection with his hoses from his truck to the plant. and you can see suddenly something went wrong. what that was, i don't know that we'll ever know for sure. >> the truck and driver become surrounded by an ominous and dangerous cloud of extremely flammable propane. >> it's very explosive, plus, that leak happened at a very remarkable speed. it was literally, i believe, under 20 seconds. >> the driver, fearing something isn't right, tries to shut down the gas. but he's not in time. suddenly, the propane ignites. >> unfortunately, at that point, you know, it enveloped the driver, too. he was in that cloud. the driver of the truck, you can see it explode. that's horrible. >> the explosion rocks nearby buildings and businesses across the street, just a few hundred feet away. >> the whole building shook. the whole building shook. you could definitely tell that something was not right.