Worcester firefighters rescued two people from a third-floor apartment early Tuesday.
They were taken to UMass Memorial Medical Center while another person was also transported with injuries.
"It is a big complex and all the water is coming off Mill Street, the main street, down the road here. So, we did really run into a water situation with the volume of fire," Worcester Fire Chief Martin Dyer told WCVB.
Officials said dozens of residents have been displaced from the fire dsicovered about 2:30 a.m.
"I feel from the people who got it the worst. I think my building can be fixed. Theirs looks like a total waste," resident Chris Johnson said.
The cause remains under investigation.