Several units in an Arlington Heights apartment complex remain uninhabitable after a fire broke out Thursday in a first-floor unit, but no residents or firefighters were reported injured, according to a fire department news release.

According to the release, Arlington Heights firefighters and police offers responded around 4 p.m. to a report of fire inside the multiunit apartment complex in the 300 block of East Seegers Road.

Initially, the emergency responders did not know if anyone was injured or trapped inside the two-story apartment building. Upon arriving on the scene, though, the fire appeared to have started in a first-floor unit of the building, the release states.

“The first police/fire units on scene reported billowing smoke and flames showing, as well as possible extension of the fire to the second floor of the building (above where the fire started),” officials stated in the release.

There was also heavy smoke and fire that initially kept the first responders from entering the apartment unit where the fire was. Fire personnel then conducted an “expedited search and evacuation of the entire building,” according to the release.

The release explains that all residents, including a 51-year-old woman who lived alone in the apartment where the blaze is believed to have started, were able to get out of the apartment building without any reported injuries.

The release states that, “given the substantive size of the fire,” other nearby fire departments were called in to assist, including from Mount Prospect, Elk Grove, Rolling Meadows, Palatine and Schaumburg.

According to the release, an investigation into the cause and source of the fire is underway. Most residents have been able to return to their apartments, but three units remain uninhabitable as of Friday.