CHICAGO (STMW) — A blaze at a vacant South Side warehouse that left firefighter Daniel Capuano dead in December was set off by a construction worker and deemed accidental, the Chicago Fire Department announced Wednesday.

Daniel Capuano, a 15-year veteran of the department, was killed while battling a blaze at a vacant warehouse at 9213 S. Baltimore Av. on Dec. 14.

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The fire was caused by a construction worker using an arc welder that touched off insulation, according to Fire Media Affairs. The blaze was determined to be accidental.

Capuano, who was assigned to Tower Ladder 34, fell through an elevator shaft in the three-story warehouse after firefighters responded to the blaze just before 3 a.m., officials said at the time. He was searching through heavy smoke on the second floor when he fell down the shaft and into the basement.

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The city’s Department of Buildings said after the blaze that “unauthorized work” was being performed at the warehouse. Work being conducted without a permit included complete removal of the elevator and other structural alterations, spokeswoman Mimi Simon said.

On Dec. 15, building inspectors dropped multiple code violations on the owner of the building and city attorneys moved to have the building torn down. And a few days later, the Capuano’s wife, Julie Capuano, filed a wrongful death lawsuit against Anilroshi LLC, which owned the building.

Capuano was also survived by three children.

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