An autopsy found Chicago firefighter Jermaine Pelt died of carbon monoxide poisoning while battling a blaze on the Far South Side, the Cook County medical examiner’s office said.

Pelt, 49, died early Tuesday while working to put out an extra-alarm fire in the 12000 block of South Wallace Avenue.

The autopsy released Wednesday determined he died of carbon monoxide toxicity from inhalation of smoke and soot, the medical examiner’s office said.

Pelt joined the Chicago Fire Department in 2005 and was based on the South Side his whole career, Chicago Fire Commissioner Annette Nance-Holt said.

Pelts' father, John Pelt, said his son had a proud moment in November when he walked his 28-year-old daughter down the aisle.

The newlywed had delayed her honeymoon and was about to leave town for Jamaica when tragedy struck, he said.

“I would call him a hero. He’s my hero,” John Pelt said. “Right now I’m not feeling that great.”

Just a day after Pelt’s, death a Chicago Fire Department lieutenant died battling an extra-alarm blaze in a high-rise building in the Gold Coast neighborhood.

Lt. Jan Tchoryk collapsed in an 11th-floor stairwell while making his way to a fire on the 27th floor of an apartment building in the 1200 block of North Lake Shore Drive, according to fire officials.  His cause of death has not yet been determined.

Mayor Lori Lightfoot on Wednesday called the back-to-back tragedies “unprecedented.”