JASON, QUITE THE SCENE. JASON: I’M TOLD AROUND 600 EMPLOYEES GOT OUT OF THE BUILDING SAFELY AND SOME OF THEM WERE SENT HOME EARLY BECAUSE OF THE BLAZE. I’M TOLD THE FIRE STARTED IN THE MIDDLE OF THIS BUILDING HERE. >> YOU ARE SEEING THE FIRE CREWS SHOWING UP. >> SKY 5 WAS RIGHT ABOVE IT. WE GOT A CALL FROM THE HELICOPTER SHORTLY BEFORE THE FIRE ALARMS WENT OFF AT OUR FIRE DEPARTMENTS. JASON: OUR OWN HELICOPTER PILOT, CHASE RUTLEDGE, WAS THE FIRST ONE TO SEE IT FROM THE AIR. SKY 5 WAS OVER THE SCENE AS SMOKE BILLOWED FROM AN M.D. BUILDING PRODUCTS FACILITY. >> WE HAD AN ENORMOUS AMOUNT OF SMOKE COMING FROM THE ROOF AREA OF THE STRUCTURE. JASON: BUT THE FIRE DEPARTMENT THINKS THAT MIGHT BE WHERE IT ALL STARTED. >> THE MAIN BODY OF THE FIRE, WE BELIEVE, WAS ON THE ROOF. JASON: NO OFFICIAL CAUSE YET AS THE INVESTIGATION CONTINUES TONIGHT, BUT FIREFIGHTERS HAVE A THEORY. >> THE ROOF AREA WAS STARTING TO CAVE IN AROUND SOME AIR CONDITIONING UNITS, SO WE’RE NOT SURE IF IT INVOLVED THOSE UNITS OR NOT AT THIS TIME, BUT OUR INVESTIGATORS WILL BE LOOKING AT THE CAUSE. JASON: HUNDREDS OF EMPLOYEES GOT OUT SAFELY, LARGELY THANKS TO EQUIPMENT IN THE BUILDING THAT WORKED THE RIGHT WAY. >> THEIR SPRINKLER SYSTEMS KICKED ON, THE ALARM SYSTEM KICKED ON AND ALERTED THE EMPLOYEES, AND THEY ALL EVACUATED SAFELY AND WE LOVE TO SEE THAT. JASON: AND OKLAHOMA CITY FIRE SAYS THE TOTAL AREA THAT W