One person is dead after a devastating explosion levelled a house in Mississauga, Ont., and damaged 24 others.

The cause of the blast, which also left nine people with minor injuries, is still unknown. A fire official said it is too early to speculate on what led to the explosion that occurred about 4:20 p.m. ET on Hickory Drive, near Dixie Road and Rathburn Road East.

Peel Regional Police confirmed one person died in the explosion. Police declined to provide further information about the age or sex of the victim on Tuesday night.

Chief Tim Beckett of Mississauga Fire and Emergency Services said the area is now secure. He said Tuesday night that the evacuation area covered 25 to 30 homes, and a total of 50 to 100 people have been forced to leave their homes.

Beckett said there is also limited access to about 700 addresses in what he called the "outer perimeter" of the evacuated zone. That means people who were in their homes during the explosion can "shelter in place" or make arrangements to leave, and those who were not at home are not allowed to return for now.

Peel Regional Police help elderly residents leave an area near an explosion in Mississauga, Ont. on Tuesday. The explosion killed one person and left nine others with minor injuries. Police say damage to homes in the area is significant. (Pascal Marchand)

"We are continuing to conduct an ongoing operation here with respect to the safety of the area. We have shut the area down. However, there's residual gas we have to look at," he said. "Nobody outside the perimeter prior to the explosion is allowed back into the perimeter for the purposes of securing the area."

Beckett said the limited access to the outer perimeter will be reassessed on Wednesday morning.

He said Toronto's Heavy Urban Search and Rescue team arrived Tuesday night to help officials go through homes still considered unstable. The team is trained to locate, remove and provide medical attention for people who might be trapped in collapsed buildings. It is currently doing an assessment of the site.

Beckett said fire officials have yet to begin their investigation into the cause, with the focus on stabilizing the site.

"We definitely have collapsed homes and unstable homes," Beckett said. "There is definitely extensive damage to the area."

Tim Beckett, chief of Mississauga Fire and Emergency Services, said work is continuing to stabilize the scene, but 'we can't tell you any cause' of the blast. (CBC)

​The air quality in the area has been determined to be okay, he said.

"We anticipate this will be a prolonged exercise. From here on in, it's just going to be a slow process that our crews will continue to work on."

Power outages for dozens of homes

A reception area has been set up at Burnhamthorpe Community Centre, which was scheduled to stay open Tuesday night. Residents are urged to register with the centre if they need any supportive services after the explosion.

"We will be there to welcome you and make sure that you have at least a dry place to stay," Beckett said.

Const. Paolo Carretta of the Peel Regional Police said it's not known when residents currently out of their homes will be allowed to return.

"As soon as we have a time, we'll be sure to let everybody know. In the meantime, we're asking any affected residents to please attend the community centre," he said.

Mississauga Mayor Bonnie Crombie said gas and power have been cut off to 58 homes in the area, and she urged residents to stay with family and friends if possible. She said six homes received moderate to heavy damage.

"It may last more than one night," she said.

Mississauga Mayor Bonnie Crombie said 58 homes have had gas and power cut off in the area near the explosion. (CBC)

Belma Colakovic, who lives in a townhouse complex known as Hickory Village, about 10 houses away from where the explosion occurred, said she was at a nearby Tim Hortons when she felt the blast.

"All of a sudden we feel the ground shake and the windows move and the doors open and close. At first we thought it was a really bad earthquake, and then we looked up outside, and we saw that there was a huge cloud of smoke everywhere," Colakovic said.

On her walk home, the roads were blocked by police.

"There was just wood on the street … scattered all over the place," she said.

House explosion in mississauga <a href="https://twitter.com/680NEWS">@680NEWS</a> <a href="https://t.co/dy2L89P5tS">pic.twitter.com/dy2L89P5tS</a> —@VazPhotography

She said she knows one of families in the houses affected by the explosion and is trying to contact them to find out if they're OK.

"We're just praying for all those families and really hoping that they weren't home."

Toronto Emergency Services said one person was pronounced dead at the scene and nine people were treated at the scene for injuries, mostly cuts and bruises. The injured were all treated on the Toronto Paramedic Bus.

Police are asking people to avoid the area near Dixie Road and Rathburn Road East.

The evacuated area is from Eastgate Parkway to the North, Rathburn Road East to the South, Golden Orchard Drive to the West and Dixie Road to the East.

A photo taken by a Mississauga resident from his apartment building shows some of the damage. (@m_fullerton/Twitter)

Area residents have been sharing photos and video of the explosion scene on social media.

Garrett Brazzier was driving east on Rathburn Road East crossing over Hickory Drive when he stopped at the light at Dixie and Rathburn.

"I heard a loud bang, like a super-loud bang. It sounded like a bomb went off, almost. I looked in my rearview mirror and there was debris flying everywhere. There was a huge dust cloud," he said.