CHICAGO (CBS) — A Chicago firefighter and seven people staying at a South Side motel were injured Saturday morning when an extra-alarm blaze gutted the two-story building.

The fire started at about 3:30 a.m. on the first floor of the Lake Motel, 9101 S. Stony Island Av., according to Fire Media Affairs spokesman Will Knight.

A 3-11 alarm was called for the fire less than an hour later.

The flames spread through a ventilation system at the motel and up to the second floor, Knight said.

One firefighter was hurt battling the blaze and seven occupants of the motel were hospitalized.

Four people were taken to Advocate Trinity Hospital and three others were taken to Jackson Park Hospital, Knight said. All seven were in good condition.

The firefighter was taken to Advocate Christ Medical Center in Oak Lawn and was listed in “stable” condition, according to Knight.

Another 25 people staying at the hotel — 18 adults and 7 children — were taken to CTA warming buses during the fire.

The fire was out at about 8:45 a.m. The building was “a total loss,” according to Knight.

The cause of the fire was under investigation as of Saturday morning. It was not immediately known if smoke detectors were working at the motel.

The American Red Cross was also on the scene, working to assess the situation and the immediate needs of those affected, according to an email from spokesman Josh Morton.

Red Cross members were also assisting firefighters this morning by providing them with beverages to keep them hydrated as they battle the blaze, according to Morton.

(The Sun-Times Media Wire contributed to this report.)