DURHAM, N.C. (WNCN) — Dozens of people have been displaced after a Saturday night blaze at a Durham apartment complex.

The Durham Fire Department said they were dispatched to a smoke investigation in the 2000 block of Holly Hill Drive around 9:04 p.m. Saturday.

After an investigation by those in the first truck that arrived, smoke was found in one of the apartment units and the call was upgraded to a structure fire. More trucks and firefighters — a total of 33 personnel — were called in to help.

The source of the fire was eventually found in the wall between apartments, but it was also discovered that the blaze had traveled to the attic space.

According to the fire department, it took about 20 minutes total to locate and extinguish the flames. The building’s sprinkler system did activate, but due to the location of the fire it was mostly ineffective.

Four of the building’s 24 apartment units sustained fire damage and eight others were damaged by smoke or water, the fire department said.

Power had to be disconnected to the whole building, leading to the displacement of approximately 36 residents. The American Red Cross was called in to help property management determine housing needs for those affected.

In addition to the Red Cross, Durham County EMS and Duke Energy also assisted the Durham Fire Department.

The cause of the fire is still under investigation.