BROCKTON — A five-alarm fire engulfed a triple-decker home on Spring Street in Brockton on Monday morning, resulting in injuries to nearly a dozen people, including residents and firefighters, authorities said.

The blaze started around 8:20 a.m. at 303 Spring St., reportedly originating near an electric fireplace in a first-floor living room, according to Jake Wark, spokesperson for the state fire marshal’s office. Upon arrival, firefighters found residents attempting to escape the flames by hanging out of windows, and some had jumped from upper floors to avoid the fire. Fire Chief Brian Nardelli described how two individuals who jumped sustained minor musculoskeletal injuries, while others suffered smoke inhalation but no serious burn injuries were reported.

In total, seven occupants, including two children, and four firefighters were taken to hospitals for treatment. All were reported to be in stable condition. One firefighter issued a mayday call during efforts to locate a resident on the second floor but was able to exit the building unassisted after reaching a window. A rapid intervention team had entered the structure to provide assistance as the situation unfolded.

Firefighters from Brockton were supported by crews from Avon, Stoughton, Whitman, and Holbrook, with more than 70 personnel involved in the operation. The fire was brought under control in roughly an hour.

While the front corner of the building suffered significant damage, city building inspector Frank Gazerro indicated that only about one-third of the structure was affected and that it would not need to be demolished. Gazerro noted that a demolition would only be considered if two-thirds of the building were destroyed.

The fire caused displacement for at least two families. The Red Cross is providing assistance, offering funds for hotel stays and food, and working to contact an additional family to extend support. Relatives of the residents arrived at the scene and the hospital throughout the day to check on their loved ones, some still wearing visitor stickers. Firefighters recovered a few personal items from the damaged home, including a functioning cellphone found among the debris.

Maria Lopes, a resident who was not home when the fire broke out, expressed relief that no one was seriously harmed, saying, “We are alive, so it’s not that bad. I am glad everyone is pretty much OK.”

The street remained blocked by emergency vehicles and fire apparatus through mid-morning as crews continued cleanup and investigation efforts. The charred exterior and lingering smoke marked the scene of the incident, which remains under review by fire officials to confirm the accidental nature of the fire.