Grand Rapids, MI – Firefighters are investigating an explosion at a trucking business in Grand Rapids.

The explosion blew out windows and knocked the back wall off of its foundation at an office building inside Masselink Brothers Trucking, located at 901 Freeman Avenue SW near Market, around 4:20 a.m. Monday.

The explosion also caused a flash fire that firefighters were able to put out quickly.

The preliminary investigation indicates it was a natural gas explosion.

No one was inside the building when the explosion happened and police did not evacuate the area.

Police have set up a perimeter, but are not evacuating anyone from the surrounding area.

DTE Energy also were on scene investigating.