The duplex fire was reported at about 2:50 a.m. at 2288 Freya Drive. It was brought under control at about 6:15 a.m.
The fire is believed to have started in an attic space of one of the units, Rangel said. Flames spread and both units were damaged.
No one was injured, but three tenants were displaced and their unit was badly damaged, Rangel said. Damage to the neighboring unit was minimal.
The cause has yet to be determined.
Firefighters this morning also responded to a two-alarm fire at Sanmina-SCI Corp. at 2050 Bering Drive.
Crews responded to that blaze at 4:45 a.m. and found part of the roof on fire, Rangel said. The fire was confined to the roof and was controlled by 6:10 a.m.
A night crew was inside the building at the time of the fire, but no one was injured, Rangel said.