WLS-TV reports, Matthews fell ill while assisting during a fire at a mobile home park in Harvey.
"We were doing exterior work. It was a defensive fire. Our crews, the fire was spreading to a rubbish fire and that's where he was going to tend to. He wasn't even out there that long," said Steve McCain, Dolton fire chief.
Dolton fire officials said Matthews initially appeared to have shortness of breath and began leaning on a fence for support. He collapsed shortly after and was pronounced dead at Ingalls Hospital.
In July 2016, Matthews participated in a village of Dolton video promoting an upcoming health fair. It was a topic he was passionate about. Ten years ago last week, he had received a life-saving heart transplant, according to his Facebook page. He met his wife at the same hospital he was operated on.
Matthews, who coached Little League baseball, was 36.
"He was a jovial guy. He loved his job he was a family man of four little ones. Loved his wife. He loved his job. It's going to be tough," McCain said.
Even before getting called out to Saturday's fire, Matthews was on duty, helping to administer exams to 250 applicants to the Dolton Fire Department.
Dolton firefighter dies while fighting house fire in Harvey
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