BRIDGEPORT — As fire officials continued to investigate whether a fire at Barnum Apartments was caused by fireworks, around 40 people displaced by the blaze were moved Sunday to local hotels.

After the fire broke out Saturday night, those Barnum tenants had first been moved to Cesar A. Batalla School on Howard Avenue, which was set up as an emergency shelter directed by the Red Cross and the city’s emergency operations center.

Officials said nobody was injured in the fire. According to Scott Appleby, the director of the city’s emergency communications department, said once the fire marshal’s report is released, fire personnel will investigate the fire in conjunction with police.

Firefighters were sent to building 8 around 8:30 p.m. Saturday for a reported structure fire. There crews found “heavy smoke” and fire on the roof of the building, according to dispatch reports.

By 9 p.m. crews on scene were reporting “heavy fire” from the roof of the building. The bulk of the fire was put out around 20 minutes later, but firefighters remained on scene to mop up hot spots.

The department said around 20 fire units responded to the two-alarm fire. The Bridgeport Fire Department said in a brief statement Saturday night that fireworks were the “possible cause.”

Aerial fireworks, which are illegal for non-licensed users in Connecticut, have become a mainstay in Bridgeport and around the country in recent weeks. Residents have complained of their telltale bangs and flashes happening through the night and into the early morning.

Bridgeport police responded to 264 fireworks calls between May 1 and June 24 compared with 112 such complaints between May 1 and July 31 last year, according to data provided by Scott Appleby.

In Norwalk, police received 132 fireworks complaints between June 1 and June 24, Lt. Jared Zwickler said. That’s 116 more complaints compared with the same period last year.

Bridgeport City Council member Marcus Brown recently said he and city officials were setting up a hotline for residents to call when they saw illegal fireworks activity. And police in Fairfield issued a stern warning last week on Facebook about the illegal use of fireworks after a marsh blaze was ignited last weekend that injured three firefighters and stopped Metro-North trains in the area. Neighbors reported hearing fireworks minutes before the blaze was spotted behind a woman’s property, firefighters said.

Julie L. Heckman, executive director of the American Pyrotechnics Association, said the fireworks industry has seen record sales, with some retailers reporting 200 percent increases from the same time last year.

She said high hopes for sales around the Fourth of July, which fell on a Saturday, were originally tampered by the coronavirus pandemic. Those fears were apparently unfounded.

“Sales are off the hook right now. We’re seeing this anomaly in use,” Heckman said. “What’s concerning to us is this usage in cities where consumer fireworks are not legal to use.”

Past reporting by Tara O’Neil, Erin Kayata and Lisa Backus was included in this report.