A heavy fire broke out at a one-story commercial building in Joliet on Saturday morning.

The Joliet Fire Department was en route to the 700 block of West Jefferson Street in Joliet in response to an automatic fire alarm activation when dispatch received additional calls of a building on fire, according to a news release from the department.

When firefighters arrived at the building at 3:49 a.m., they found a one-story commercial building “with heavy fire showing from the front windows,” according to the release.

The fire was under control at 4:13 a.m., according to the release.

Search and rescue crews determined no one was inside the building at the time of the fire, according to the release.

No civilians or firefighters were injured, according to the release.

Firefighters from Joliet Fire Stations 5, 1, and 6 were on scene, which included two ladder trucks, according to the release.

The fire is under investigation, according to the release.