Two people were rushed to the hospital after an apartment complex fire in Northglenn. The fire broke out before dawn on Thursday morning at the Huntington Square Apartments. 

Firefighters told CBS News Colorado that three units were impacted at the complex located near E. 105th Place and Washington Street. Crews with North Metro Fire Rescue rushed to the complex at 4:31 a.m.

When crews arrived, they saw heavy smoke coming from the building and heard explosions. They requested additional resources due to the fire conditions. 

According to North Metro Fire, crews were able to quickly contain the fire to the initial unit and two others. 

Residents described a chaotic scene after hearing what they said sounded like an explosion.

"I went to the bathroom, and I heard this explosion or whatever. I thought somebody may have hit our building with a car. I opened my door, and I heard a screen and drapes for the window on the front of our door. Blew completely out the window," said resident Jennifer Deaguero. 

What caused the fire is being investigated. The Red Cross and ATF will be assisting with the investigation, according to North Metro Fire. 

The conditions of those taken to the hospital had not been released as of Thursday morning.