Firefigthers responded about 10:45 a.m. Monday to a report of a fire at a four-plex at Quailwood IV Condominiums in the 200 block of Gage Boulevard.
The eastbound lanes of Gage were closed while they fought the fire, which was in the wall of the home, causing traffic backups.
Fire damage was limited to one unit, said Richland fire Battalion Chief James Hempstead. The cause is under investigation.
Firefighters from Richland, Kennewick, Pasco and Hanford fire departments and Benton fire districts 4 and 1 responded.