Officials say a fire that claimed a life and displaced more than 100 people in Dartmouth last month was likely caused due to "careless use of smoking materials."

Fire crews responded to the 80-unit apartment building at 81 Primrose Street around 3:35 a.m. on May 19.

A woman’s body was pulled from the building and another person was sent to hospital with serious injuries.

Halifax Regional Fire and Emergency says it has closed its investigation and concluded that the likely cause of the fire was careless use of smoking materials.

“Investigators use the term ‘likely’ in describing the source because in this case the official cause is undetermined,” said city spokesperson Brendan Elliott in a news release.

Investigators say the fire originated near a couch in the living room of a unit on the third floor, but that any evidence that could confirm an official cause was destroyed in the fire.

“What we do is we look at any potential causes, and we rule out potential causes,” said Halifax Regional Fire and EmergencyDeputy Chief Roy Hollett. “In this case, we ruled out electrical, so we brought in an electrical engineer and ruled that out, We rule out other areas that could have caused the fire.”

Initially, fire officials estimated that up to 150 tenants may have been displaced by the fire, but the Red Cross later said a more likely number appeared to be around 115.

The fire department says this building did not have a sprinkler system.  With a building this age, such a system is simply recommended, but not required by regulations.

“In an apartment with no sprinkler system, and a fire starts in that confined space, it can move pretty quick, and this one did,” Hollett said. “It got to the outside, got to the balcony, which was wood, and entered the apartment upstairs and into the roof and that can be within minutes.”

Hollett says it's now up to the building owner to determine what should be done with what's left.

A statement from the rental property company says it did not receive word from investigators on the cause of the fire.

The president of Northview REIT says the company is still assessing the damage and figuring out how to rebuild, but that early indications are that some residents may be able to return within 90 days.

A resident who spoke to CTV News by phone says some displaced tenants are meeting with a lawyer Thursday.

With files from Heid Petracek.