VIDEO: Transformer explodes near firefighters in Florida

ST. PETERSBURG, Fla. (WPVI) -- New video shows just how quickly a smoky scene turned dangerous for first responders in St. Petersburg, Florida.

Hannah Rebholz and Vanessa Herring called the fire department after noticing a menacing-looking plume billowing from a manhole.

It's a good thing they did because soon after firefighters cordoned off the sidewalk, the underground transformer exploded.

Even though the blast sent flames shooting into the air, nobody was hurt.

Officials are still trying to determine what caused the explosion.