fire department is aware of the boilover danger but believes they have it under control. >> we will stop operation in ten minutes. >> firefighters can prevent a boilover from happening by making sure the water sprayed on the tank drains out the bottom. this time, they miscalculate. >> what do you think caused that explosion? >> just water inside the tank boiled over. crude boil-over. >> despite the chaos, david's instincts kick in. he keeps taping as he runs away from the intense heat and flames. >> for a split second i thought this is it. how i had the presence of mind to point the camera backwards and run, to this day, i can't explain it but i thought this is it, i better at least catch it on tape. >> more than 30 people are burned by the blast, including david, who radios for help. >> smitty, this thing blew up. we're going to have burn victims. >> i had blisters the size of oranges on my arm and it was pretty painful and needed to be treated. i was out of work for like three months until i recovered.