Crews are investigating the cause of a fire that occurred at an apartment building in Pawtucket early Tuesday morning. According to officials, the blaze began in an unoccupied unit around 1:30 a.m. and residents in the 12-unit structure on Trenton Street had to be evacuated. Fortunately, there were no reported injuries. Crews are still attempting to restore the fire alarms. Stay informed by downloading the 12 News App for breaking news alerts on your mobile device or tablet.