Authorities said the blaze began inside Parts Depot and spread to Elite Auto, a junkyard right next door, at about 10:15 p.m. Saturday.
Firefighters said the junkyards had a small amount of combustible metals.
It took nearly 100 firefighters more than an hour to put out the fire.
Firefighters planned to stay on the scene overnight watching for hot spots.
The cause of the blaze was under investigation.