A fire that caused a thick wall of smoke burned a garage near a duplex and severely damaged the building, said a Middletown fire chief.

The fire broke out at about 5:44 p.m. Friday, and when firefighters arrived, they found the garage at 5042 Windsor Road engulfed in “heavy flames and smoke,” said Deputy Chief Paul Lolli.

The garage, a brick structure measuring about 800 square feet, was next to a duplex. Firefighter’s progress was impeded by the cold temperatures, which were about 15 degrees, Lolli said.

“It was so cold, the initial hydrant we caught was frozen, so we had to go further up Dixie Highway,” he said.

It took 21 firefighters about half an hour to extinguish the blaze, which caused about $20,000 of damage. Monroe firefighters provided mutual aid.

The fire is still under investigation, but “we’re looking at a possible a space heater. The occupants of the apartment were going to do some work in there, and they turned it on and left it,” said Lolli.

No charges are expected to be pressed, and there were no injuries.

“Just cold firefighters,” said Lolli.