Fire crews were called to the 1100 block of Pearl Street Thursday to investigate a report of smoke in a building.
According to Boulder Fire-Rescue spokeswoman Jamie Barker, at 4:39 p.m., Boulder Fire-Rescue crews were dispatched to a building at 1101 Pearl St., which houses two separate businesses - Billabong and the Boulder Bookstore.
Barker said the call originated from Billabong but that some people at the bookstore noticed the smoke as well.
"Upon arrival, crews worked to continue to evacuate folks and find the source of smoke," said Barker.
After an investigation of the building, crews determined that the cause was the furnace in the basement, which was being serviced, according to Barker.
At 5:28 p.m., Boulder-Fire Rescue announced that the scene was clear, according to a post on X.