AUBURN — Fire ripped through the back of a four-unit apartment building at 18 Hazel St. early Wednesday morning, displacing a dozen people and sending one firefighter to the hospital, authorities said.

The building, valued at between $200,000 and $250,000, was a total loss but was insured, Deputy Fire Chief Matthew Fifield said.

One of the tenants suffered minor injuries that didn’t require medical treatment, he said.

A Lewiston firefighter on scene was taken to a local hospital with heat exhaustion, Fifield said.

All 12 of the building’s occupants were out by the time firefighters arrived on scene, helped out by other tenants, he said.

The fire was reported shortly before 5 a.m.

“There were some pretty dramatic few minutes there before our arrival when a couple of the tenants on the second floor struggled to make it out of the building and ended up having to go onto a porch and were assisted by one of the other tenants with a ladder and were able to get to safety,” Fifield said.

A couple of pets on the third floor were taken safely outside by the tenants.

Firefighters were met with heavy fire on the first and second floors at the back of the building, according to Fifield, and it took crews several hours to get the blaze under control.

The American Red Cross is involved in assisting in finding housing for one of the tenants, he said.

The Maine Office of the State Fire Marshal investigated and is expected to release findings Thursday.

Fifield said the fire appears to have started on the first floor inside the building. The cause was undetermined as of Wednesday, but didn’t appear to be suspicious, he said.

This was the fourth Auburn structure fire involving occupants in the past five days.