Naperville business damaged by fire

A fire broke out at a Naperville business Saturday afternoon, causing extensive damage inside, authorities said.

No injuries were reported in the blaze in the unidentified business on the 2000 block of Aurora Avenue, fire officials said.

An employee called 911 about 1:05 p.m. Saturday to report that the fire alarm went off and smoke was coming out of a rear storage room. The first units arrived about five minutes later and saw nothing from three sides of the business. But once inside, the fire was producing heavy smoke.

Firefighters upgraded an alarm to bring more equipment and personnel. Extinguishing the blaze was challenging because of the size of the structure, officials said. It took crews about 46 minutes to put it out.

Damage to the structure itself was moderate, but the contents inside sustained extensive damage from smoke, fire and water, a news release stated.

The cause of the fire remains under investigation.