AMHERST – Three peo­ple escaped injury Sun­day evening after a fire broke out in the basement of a single-family home at 5 Blueberry Hill.

Fire crews faced ex­treme heat and no vis­ibility in the finished basement of the two-story colonial house.

The house was built in 1972. The basement had undergone multiple reno­vations and the creation of small rooms, making it difficult for firefighters to locate the blaze.

The residents called 911 at 8:47 p.m. and a first alarm fire was toned. Be­cause of the heat and hu­midity, the fire went to a second alarm to bring in additional crews and pro­vide relief for firefight­ers.

"The heat-filled envi­ronment created a lot more work," Amherst Deputy Fire Chief Ste­phen Brady said Monday.

He said the fire is still under investigation and that the department isn’t ready to name a cause. Ar­son isn’t suspected.

Manpower and appa­ratus from Bedford, Mer­rimack, Milford and New Boston responded to the fire, and Hollis and Mont Vernon departments pro­vided station coverage.

One resident was evalu­ated by Amherst Fire Rescue EMS personnel, but she declined further treatment.

The house isn’t habit­able because of smoke and heat damage. Brady said the residents, all adults, have found tempo­rary living quarters.

In a press release, Brady reminded resi­dents that a basement with finished living space requires two means of exit and proper building permits before construc­tion can occur.