Fire crews are investigating the second fire in little more than a month at Valley Creek Apartments.
The complex is off Fairforest Road in Spartanburg County.
Westview Fairforest and other fire departments arrived on scene shortly after 8 a.m. Tuesday.
Flames could be seen tearing through the roof of a unit.
Firefighters say the blaze started on the third floor and no one was inside when it started.
No one was reportedly hurt.
The Red Cross says it is helping four families whose homes were damaged, including six adults and six kids.
Fire crews were called back to the scene due to reports of smoke around 3:30 p.m.
Crews were on scene putting water on the building. The fire chief said the fire didn’t necessarily rekindle and smoke is likely for the next couple of days.
They will be monitoring it.
The chief says they don’t have a cause or point of origin yet.
There was a fire at the same apartment complex on May 16. Authorities say several families were left without homes following that fire.