If you heard a loud boom in the Tulsa area just before 6 p.m. Friday night, you're not alone.

Fire crews tell us an explosion happened inside a vacant building near Admiral and Utica.

"Our crews arrived to find a building with heavy flames involved and significant structural damage," TFD said.

A second explosion happened inside the vacant building after crews arrived at the scene.  Crews were able to pull back, without anybody getting hurt.

We're told 15 trucks and 50 firefighters were at the scene.  Crews were able to get the fire contained quickly.

There have been no reports of any injuries.

TFD says a cause for the explosions is still under investigation.