Alta, UT – An apartment building is a total loss after it exploded Saturday then caught fire, causing an estimated $1 million in damage but no injuries, according to officials.

The explosion occurred in the attic of the building where Keith Garner, public information officer with Unified Fire Authority, confirmed a gas line leaked natural gas into the area.

The exact cause of the leak and explosion is under investigation.

The blast occurred around 4 p.m. in a four-unit complex of condos/apartments located at 9740 E. Bypass Road, specifically in the bottom right unit.

The homeowner of that unit smelled gas and exited about five minutes before the explosion, unharmed, Garner said. No one else was inside the other units at the time of the blast.

Crews were still fighting active flames in the attic and checking for hot spots late Saturday evening. An overnight crew was assigned to keep watch on the building.

All residents of the complex are displaced, and residents of nearby buildings may also be displaced for the night because of a power outage affecting surrounding buildings.

The family that lived in the unit where the explosion happened consists of two adults and one 12-year-old.

According to Utah Department of Transportation, the fire affected roadways but was cleared a few hours later.