Their efforts were hampered by the bitter cold.
Frozen fire hydrants were prevalent, and at least a half dozen neighboring fire departments responded to each blaze with engines or water trucks.
The first fire started shortly after 10 a.m. in the attached garage of a home in the 15400 block of South Birch Road, Markham Fire Chief Ronald Moaton said.
A 27-year-old Hazel Crest firefighter was badly burned when he fell through the roof of the garage, Hazel Crest assistant fire chief John Grady said.
The firefighter was pulled to safety and taken to St. James Hospital in Olympia Fields, Grady said.
He was later airlifted to Loyola University Medical Center in Maywood, Grady said.
His condition was unknown Sunday night.
"All of our thoughts and prayers are with him and his family," Grady said. "He's a tough guy, and I'm sure within a few days he's going to be back on the engine."
Grady said the injuries suffered by the firefighter, who has worked for Hazel Crest for five and a half years, were the worst in the history of the fire department.
"We've had guys burned before, but never to this extent," he said.
A Country Club Hills firefighter also was injured in the fire when he was struck in the head with a hose, Country Club Hills fire Lt. Steve Pyzc said.
He was taken to South Suburban Hospital in Markham. Stiches were needed to close the gash in his head, Pyzc said.
No one was home at the time of the fire, which was contained to the garage. The cause of the blaze is under investigation, Moaton said.
Smoke and water damage rendered the house uninhabitable, Moaton said.
The American Red Cross is helping the family.
Just after 5 p.m., a fire broke out in the attic of a one-story home in the 16200 block of Dixie Highway. No one was in the house at the time, and fire officials were unsure if anyone lived there.
The fire burned for an hour and a half, in part because firefighters could not get any water from the frozen hydrants.
Hoses were hooked up to hydrants several blocks away and to water trucks brought to the scene by other fire departments, including Oak Forest and Flossmoor.
The fire went to a second-alarm. The cause was not known.