SALT LAKE CITY (ABC4) – Firefighters successfully contained a three-alarm structure that fire broke out in Salt Lake City Thursday evening.

The fire was located at the Towers on Main Apartments near 1800 S. Main St.

When firefighters first arrived on scene, they had issues getting to the fire, as it was located four stories into the building and towards the center of the complex.

Courtesy: SLC Fire

Eventually, however, they were able to contain the fire to just one apartment unit, according to Captain Tony Stowe with the Salt Lake City Fire Department.

This photo shows heavy, black smoke billowing from a window of the building at the time of the fire.

According to Stowe, three firefighters received medical treatment, two of which are being treated at the scene for heat exhaustion and one is being treated for a fall-related injury. One resident is being treated for smoke inhalation. Portions of the large complex were evacuated as crews worked to extinguish the flames.

The cause of the fire is under investigation.

As this fire burned in Salt Lake City, authorities are continuing to investigate a separate apartment fire in Murray that left dozens without a home Thursday morning.

Murray Fire tells ABC4 there is a person of interest in this investigation.

Previously, two people had been identified as suspects. Since then, Murray Fire has cleared one of those individuals.