The deadly blaze was either started by a malfunctioning oxygen concentrator or smoking materials in a resident's room, authorities said.

Officials announced Tuesday a preliminary investigation shows an oxygen tank malfunction or smoking may have caused the deadly Fall River assisted living facility fire that claimed the lives of 10 last week.

Smoking or an oxygen machine issue may have sparked the deadly fire at Gabriel House Assisted Living Facility in Fall River, Massachusetts, a state fire marshal said.

The Massachusetts State Fire Marshal revealed the possible causes of the fire that killed 10 people at an assisted living facility in Fall River.

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,

Police released body-worn camera video showing rescues from the night an assisted living facility in Fall River, Massachusetts caught fire, killing at least nine people.

More than 75 percent of Gabriel House residents are enrolled in Medicaid, state officials have said, and it charges significantly less than a typical assisted living facility does for private-paying patients.