may 7th, 2009. a dashboard camera on a fire truck records firefighters investigating a gas leak at a strip mall in forestville, maryland. suddenly -- >> the gas finds an ammunition point and explodes. the whole roof kind of lifts off. >> you see glass flying out, debris, bricks. >> sound the mayday call. sound the mayday call. we have an explosion in the building. sound the mayday call. >> that's a term we never want to hear. that means that one of our own is lost, trapped, disoriented or, even worse, down. >> when the smoke clears, several firefighters are injured. but, luckily, the entire crew survivors the blast. >> as a firefighter, when i see a video like this, it reminds me that we have to always expect the unexpected. >> an accidental fireworks show rages out of control. november 3rd, 2004.