By KIMBERLEE KRUESI and PATRICK WHITTLE, Associated Press

FALL RIVER, Mass. (AP) — The cause of a fire at a Massachusetts assisted-living facility that left 10 people dead remains undetermined for now as officials investigate whether smoking materials and an issue with a medical oxygen machine may have been factors, officials said Tuesday.

The state’s deadliest blaze in more than four decades has highlighted the lack of regulations governing assisted-living facilities that often care for low-income or disabled residents.

The state fire marshal, Jon Davine, said the presence of medical oxygen contributed to the spread of the July 13 fire at Gabriel House in Fall River. The blaze left some residents of hanging out windows of the three-story building screaming for help.

The fire in the blue-collar city in southern Massachusetts remains under investigation but authorities believe it happened unintentionally, Davine said at a news conference Tuesday.

“Please, there’s truly no safe way to smoke. But smoking is especially dangerous when home oxygen is in use,” he said.

Members of the local firefighter’s union have said a lack of emergency personnel staffing in the city made responding to the blaze more difficult, and made the fire itself deadlier.

Earlier Tuesday, Massachusetts Gov. Maura Healey said the state was releasing $1.2 million for Fall River to hire more emergency response personnel. She also said additional funds will be expedited for the state’s municipal public safety staffing program.

“We are here today to listen to make sure that we understand what this community needs now and moving forward in the wake of this tragedy,” Healey said.

Healey said last week that a state agency that ensures regulatory compliance at assisted-living residences will investigate all 273 such facilities in Massachusetts to make sure they are prepared to protect residents during emergencies. She said Tuesday that work has begun.

The district attorney’s office identified the 10th victim as Halina Lawler, 70, on Monday. The victims of the fire ranged in age from 61 to 86.

A resident of Gabriel House filed a lawsuit Monday alleging the facility was not properly managed, staffed or maintained, that residency rules were not enforced “and emergency response procedures were not put in place.”

Trapped in his room during the fire, Steven Oldrid was in an “already compromised physical condition” when he suffered smoke inhalation and lost consciousness, according to the complaint filed in Bristol County Superior Court. As a result, Oldrid says he has increased mobility restrictions and has racked up medical bills for treatment.

George K. Regan Jr., a spokesperson for the facility owned by Dennis Etzkorn, did not immediately respond to an email seeking comment on the lawsuit. A phone message was also left with Oldrid’s attorney.

Public injury law firm Morgan & Morgan also said last week it was hired to investigate the fire by the family of one of the residents killed at Gabriel House.

Morgan & Morgan Communications Manager Emily Walsh said the law firm had already begun looking into whether the facility was adequately staffed and provided proper training to staff, as well as any potential code violations and possible failures of fire safety equipment.

Etzkorn has said he is cooperating with investigations into the fire. Gabriel House issued a statement Monday emphasizing the importance of finding out “exactly what caused this catastrophe, and if there were factors that made it worse.” The statement said the facility placed a premium on residents’ safety.

“Maintaining compliance with all safety and building codes has always been our priority, and there were quarterly inspections of the fire suppression system – the latest as recently as five days prior to the fire,” said the facility’s spokesperson.

Whittle reported from Portland, Maine. Associated Press writer Leah Willingham in Boston contributed.