Two residents were displaced, and three firefighters were injured while battling an hours-long fire at a downtown DeKalb duplex Saturday, authorities announced Monday.

Authorities said the accidental fire appeared to have erupted when someone attempted to use a torch to thaw frozen pipes in the basement.

It took 4.5 hours to get the fire under control in freezing weather conditions, authorities said.

The two-story, two-unit home in the 700 block of East Lincoln Highway, adjacent to a BP gas station off Seventh Street, appeared heavily damaged Monday morning.

Temperatures were about the same Monday morning as they were midday Saturday when the DeKalb Fire Department was called to the blaze: A biting, frigid cold, with subzero windchills.

Temperatures are expected to remain in single digits on Monday, but warm up beginning Tuesday, according to the National Weather Service.

The DeKalb Fire Department offered tips to residents to stay safe this winter and hopefully avoid future fires.

“With the continued forecasted cold weather, the DeKalb Fire Department would like to remind everyone to be fire smart and prevent winter fires,” authorities said in a news release. “Common causes of winter fires are related to heating appliances, space heaters, fireplaces, and thawing frozen pipes.”

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Sycamore firefighters walk toward a two-story duplex to help the emergency response on Saturday, Jan. 24, 2026, at Seventh Street and East Lincoln Highway in downtown DeKalb. (Kelsey Rettke)

More than a dozen emergency agencies came out during the seven-hour response, according to the fire department. DeKalb firefighters responded to the call at about 12:42 p.m. from the station right behind the duplex.

The fire started in the basement and quickly spread to the rest of the building, into the walls, and up through the attic.

Plumes of dark smoke billowed into the air for hours on Saturday.

And though residents were safely evacuated, firefighters swiftly learned they also couldn’t remain inside the building, Fire Chief Luke Howieson said Saturday. Ladders were set up to try to gain access through upstairs windows so water could be hosed inside.

Emergency personnel from Cortland, Genoa-Kingston, Shabbona, Somonauk, Maple Park, Sycamore, Malta, Richelle, Elburn, Waterman, Sugar Grove, ComEd, Nicor, and DeKalb police, along with other city departments, assisted in the response.

The duplex is uninhabitable due to damage, authorities said.

This is a developing story thatdepartments will be updated.