Dozens of firefighters responded around 10:30 p.m. Tuesday to the three-alarm fire in the 200 block of East Imperial Highway. At one point, the roof collapsed. No firefighters were injured. The cause of the fire remains under investigation.
"We haven't been able to get inside to investigate yet because of the instability of the structure," said Division Chief Julie Kunze of the Fullerton Fire Department.
The businesses in the 25-year-old building include a dental office, a graphics company and a clothing distributor.