Bloomington firefighters battle a business blaze Thursday at 1115 E. Lafayette St. Twenty minutes after search efforts were concluded and the building evacuated, the business’ roof collapsed. (Photos by Matt Swaney)

An extra-alarm fire Thursday caused significant damage to a one-story Bloomington business.

The Bloomington Fire Department is investigating the cause of the blaze at 1115 E. Lafayette St.

At 8:21 p.m. Thursday, the Bloomington Dispatch Center received a fire-alarm activation from the location. Firefighters arrived on the scene at 8:26 p.m. to find smoke emanating from the building. Crews immediately entered the building to conduct a search and investigate the source of the smoke.

After 20 minutes of searching and investigating amid increasing heat and smoke, firefighters located the fire within the attic space of the building’s bowstring truss roof system. Recognizing the dangers of this type of construction, which has historically led to sudden catastrophic failures and firefighter fatalities, including the Waldbaum’s Supermarket in 1978, Hackensack Ford in 1988, and a Chicago commercial building in 2010, command ordered an immediate evacuation.

Within 20 minutes of evacuation, a significant portion of the roof collapsed without warning, demonstrating the critical importance of the decision to withdraw personnel, Bloomington fire personnel said.

Forty firefighters battled the blaze, deploying two master streams and four large hand lines, flowing 2,000 gallons of water per minute. The fire was declared extinguished at 12:47 a.m. today.

A Bloomington firefighter walks amid the smoke at the Lafayette Street fire.

“The training and decisive actions of our firefighters were instrumental in preventing injuries during this challenging incident,” stated Bloomington fire Deputy Chief of Training Carl Reeb. “The inherent dangers of bowstring truss construction are well-documented, and our crews responded with professionalism and expertise.”

Off-duty firefighters were recalled to staff reserve units, ensuring continued coverage for the city. During that time, personnel responded to 10 additional 911 calls.

The Bloomington Fire Department received assistance from the Bloomington Police Department, City of Bloomington Development Services, Normal Fire Department, Nicor and Ameren.

No firefighters or civilians were injured.

Bloomington fire officials reminded business owners to install and maintain a fire-alarm system.