GILBERT, Ariz., -- Gilbert fire department has determined it is safe for neighbors who were evacuated Saturday night following a three-alarm fire to return to their homes Sunday morning.

More than 100 firefighters responded to the three-alarm fire at an apartment complex that was under construction near Gilbert and Juniper roads Saturday night.

Fire officials said about twenty or so occupants were evacuated because carbon monoxide levels were dangerously high.

The cause of the fire is currently under investigation.