Firefighters allowed tenants to return to their Montreal building to collect their most important belongings Wednesday morning, a day after the building was suddenly evacuated.

Around 30 tenants lined up outside of the converted industrial building in the city's Mile End neighbourhood . They were being allowed in a few at a time and were being given 10 minutes to collect items.

Tenants wait to be let inside their building to collect their belongings on Wednesday morning. The building was evacuated suddenly the night before due to safety violations. (CBC)

The tenants were evacuated from the building on de Gaspé Avenue by firefighters Tuesday night after fire department inspectors found the building lacked working fire detectors, proper exits and proper storage spaces. The hallways were also obstructed, they said.

Officials could not say when or even if the tenants will be allowed back inside to live in building, which is made up of 40 lofts.

Many tenants were staying in hotel rooms provided by the Red Cross, or with friends and family.

Several expressed concern about what will happen with their apartment and their rent.

"I hope I can get the rent back 'cause it's 900 bucks and it's a lot of money," said Mona Vachon, who had just moved into the building last week.

Another tenant who works in construction said he worked a 14 hour day Tuesday in the heat, only to come home and find the doors of the building chained shut.

The building also houses a number of small businesses owners and artists.

On Wednesday morning, guitar maker Jeremy Clark used his 10 minutes to collect his instruments.

"My workshop is on the third floor," said Clark. "I share the workspace with two other guitar makers.

"We spent the last two years using that space to make a living."

Firefighters are investigating whether the building had been zoned for residential use.