Firefighters and emergency personal work at the scene after a home explosion happened in Mississauga, Ont., on Tuesday, June 28, 2016.Nathan Denette/The Canadian Press
The investigation into the cause of a massive residential explosion in Mississauga is looking at the possibility that gas was involved and checking for clues from handwritten notes found at the scene.
Peel Regional Police Chief Jennifer Evans told reporters Wednesday that letters that suggested a cause were discovered in the blast area and had been turned over to investigators.
She did not provide more details. "It's too early to speculate," Ms. Evans said.
The notes alluded to financial problems, according to people who shared them on social media.
"Dear God, as of next week everything will fall apart for us," said one note that was shown to a Toronto Star reporter.
It also said: "We owe mortgage, company, house taxes, water bill, gas bill, hydro bill" and "our outside looks like crap, unkept lawn, overgrown plants, bricks on wall cracking."
Police and fire officials cautioned that the investigation was still at a preliminary stage.
Search teams are looking for signs of "what might have introduced whatever gas into the home that caused this explosion," said Jeff Minten, supervisor of investigations for the Ontario Fire Marshal's office.
"We're looking to see what kind of fuels there were. Gases are predominantly going to be our focus, but we may find evidence of something else," he added.
The explosion at a house on Hickory Drive killed one woman, whose identity has not yet been released, injured nine others and forced about 100 residents out of their houses.
Sniffer dogs searched the area and have not spotted other victims, Mississauga Fire Chief Tim Beckett said.
Mississauga Mayor Bonnie Crombie said it was fortunate the explosion occurred around 4:20 p.m., when fewer people were home.
"The devastation is pretty significant. However, it is relatively contained to the immediate vicinity," Mr. Minten noted.
While cautioning against premature conclusions, he said the level of devastation suggested there were just enough flammable gas in the air.
"We're not going to read too much into that. When you get into the mixture of gas that causes an explosion, there are explosive limits. And it might mean that we were at the bottom end of the explosive limits."
Mr. Minten said investigators will look for items of significance, moving inward from the perimeter of the disaster area.
Once they get to the blast site, they will need heavy equipment to allow them to sift through the debris, he said.
The investigation, which started Wednesday morning, will take a long time, Mr. Beckett said.
Teams of building and fire inspectors will assess the damages in the area. Returning homeowners are asked to report structural problems to the city's 311 phone line.
The city said it had reduced the evacuation perimeter to Rathburn Road East on the south, Dixie Road on the east, and the L-shaped Hickory Drive on the west and north.