Fire Breaks Out on Warner Bros. Lot, No Injuries Reported as Firemen Put Out the Blaze

variety.com:

Warner Bros. left a cloud of smoke billowing over the Burbank lot, but luckily firefighters were able to quickly contain the blaze.

There were no injuries, according to an individual familiar with the incident. The fire was first reported by the Citizen app, which had video of the smoke, as well as a caption that said, “Firefighters report a burning transformer and are working to contain the blaze.” The post also said that, “Firefighters report that a power outage has occurred after an explosive sound.” The fire started right around 1:30 p.m.

PT and giant clouds of black smoke quickly gathered in the air. The blaze caused lots of traffic outside the studios as a result of the fire department working quickly.

It appears to have been caused by a power transformer that busted, according to the source, and there is no evidence that it was the result of arson or foul play.