The seven-alarm blaze that tore through a Fenway apartment building, leaving more than 100 residents homeless and causing an estimated $10 million in damages, was electrical in origin, according to fire officials.

The fire is believed to have started on the second floor of the five-story building at 104 Hemenway St., said firefighter Marc Sanders, a spokesman for the Boston Fire Department.

The department’s Fire Investigation Unit has determined the fire to be unintentional and the result of an unspecified electrical circuit, he said.

The blaze left 11 people injured Saturday, including four firefighters.

On Sunday morning, firefighters were examining the structural integrity of the building to make sure it was safe enough for city inspectors to enter, Sanders said.


The building’s second, third, and fourth floors had collapsed, along with its roof, and the damage could be seen through its shattered windows. Daylight was visible through one of the building’s fourth-floor windows.

“It appears there was some serious structural damage done to the building,” Sanders said.

The building is owned by Bobson Residential LLC and has an assessed value of $4.2 million, according to city records.

Students living in the building attend local schools, including Northeastern University and the Berklee College of Music, and were moved to temporary housing Saturday night, officials said.

Two neighboring buildings — 98 Hemenway St., owned by Berklee, and 108 Hemenway, also owned by Bobson — were also evacuated during the fire.

Sanders said the two buildings are separated from 104 Hemenway St. by firewalls, though the fire was able to spread into the top floor of 108 Hemenway St.

Despite the heavy damage, there were no serious injuries, said Sanders, who attributed that to the work of firefighters and the timing of the fire, which was reported at 3:17 p.m. Saturday.

The extent of the injuries likely would have been much worse if the fire had broken out when residents were sleeping.


“I think we’re in a better place than we would have been had this occurred a bit earlier in the morning hours,” Sanders said.

Outside the apartment building Sunday morning, Boston firefighters, along with crews from Eversource and Boston Inspectional Services, clustered in groups on the street and entered the front door.

In the afternoon, residents of 98 Hemenway St. and 108 Hemenway St. could be seen entering the buildings in small groups, and leaving a few minutes later clutching some of their belongings.

Officials at local colleges said they would step up to offer help to their students in the fire’s aftermath.

In a statement, Berklee’s president, Roger H. Brown, said Sunday that no Berklee students were injured in the blaze.

“Our Student Affairs on call team, Public Safety, and Facilities teams spent all day yesterday reaching out to students, fielding hundreds of phone calls, and working to relocate displaced students into empty dorm and hotel rooms, and the homes of local students and families who took in Berklee students last night,” Brown said.

Northeastern’s president, Joseph E. Aoun, said in a statement sent to students Sunday that dozens of students were affected by the fire, a number of whom were relocated to on-campus housing. He urged students who were affected by the fire to contact university officials.

“Northeastern is more than an academic community; we are also a family,” Aoun said.


Emerson College in a statement Saturday said two of its students were displaced because of the fire and are being housed in a residence hall.

The college has offered assistance to Northeastern and Berklee in relocating their students, Emerson said.

On Sunday morning, Northeastern student Michelle Jeffery, 21, and her parents were among the onlookers gathered across the street from the burned-out apartment building.

Jeffery was driven from her apartment on the fifth floor of 108 Hemenway St. by Saturday’s fire. She said she realized there was a problem when she smelled smoke while she was studying in her room.

“When I looked out my window, I couldn’t see anything, so I just grabbed my roommates, dialed 911, and ran outside,” Jeffery said.

But Jeffery said she was ready for the emergency: Her mother, Tracy Jeffery, served for 28 years as a firefighter in New Jersey.

“I knew what to expect” Jeffery said. “I think that helped me a lot, just to stay calm and help other people.”

After she escaped Saturday, she called her parents, and they drove up from New Jersey and arrived in Boston around 8:30 p.m. Saturday. Jeffery stayed the night with her parents in a hotel room, she said.

Tracy Jeffery wiped tears from her eyes as she surveyed the damage done to her daughter’s apartment building.

“It’s just different, when it’s personal, when it’s family,” Tracy Jeffery said. “I’ve been in fires for years, and I knew she was OK, but still, it was sad.”


John Hilliard can be reached at john.hilliard@globe.com. Alejandro Serrano can be reached at alejandro.serrano@globe.com.