A Chicago firefighter was taken to a hospital Saturday morning after an extra-alarm fire at a commercial building where a mayday alert was sounded until all firefighters were accounted for and out of the building, fire officials said.

Around 7 a.m., the Chicago Fire Department was called to a vacant structure located at 5539 S. Damen Avenue.

The fire escalated and a 2-11 alarm was called at the scene because more equipment was needed to extinguish the blaze and one crew member needed immediate assistance, and was possibly briefly unaccounted, fire officials said.

One firefighter was injured but his condition had stabilized, fire officials said.

The fire has been put out and officials were investigating the cause of the blaze.