Toronto police have found a body at the scene of a weekend blaze that sent massive fireballs into the night sky, and startled thousands of nearby residents.

The remains have not been identified, but officials have been searching for a missing employee at the propane facility where the fire erupted.

Parminder Saini, who works for Sunrise Propane Industrial Gases, has been missing since early Sunday.

Meanwhile, about 100 homes that were in the path of the explosions remain uninhabitable because of asbestos, Toronto police said Monday afternoon.

The homes, stretched through eight blocks in the Keele Street and Wilson Avenue area, will not be open to residents until the Ministry of the Environment deems the air quality safe.

Deputy Police Chief Tony Warr told reporters Monday afternoon that he did not know when the area would reopen.

"I don't expect it to be a dreadfully long time but I can't say when that will be completed," he said at a press conference that included emergency officials and Toronto Mayor David Miller.

More than 12,000 people living in North York, Ont. were forced from their homes when several propane tanks housed at the Sunrise Propane Industrial Gases facility on Murray Road exploded just before 4 a.m. Sunday.

The impact of the blast melted parked cars, blew out doors and windows and shook the foundation with tremors that could be heard kilometres away.

Almost all evacuated residents were allowed back home at around 1 a.m. Monday, nearly 24 hours after they were evacuated. Police allowed several more residents to return home later in the day on Monday, but noted some residences will be without gas or electricity.

Residents not allowed to return home sought shelter with family or friends but were given the option to stay at a make-shift shelter at York University.

Miller said six people were sent to hospital with wounds Sunday, 18 people admitted themselves to an emergency clinic and that Emergency Medical Services responded to 40 people on the site.

One firefighter died at the scene but officials are investigating whether or not the 25-year veteran passed away from natural causes.

Police are asking anyone who sees something that resembles asbestos or anything connected to the explosion to contact authorities rather than handle it themselves.

Miller said at Monday's press conference that "additional asbestos has been found this afternoon."

"The problem with asbestos is that when it's disturbed and becomes airborne, it becomes dangerous to people," he said.

While dozens of homes suffered severe damage as a result of the explosion, none of them was flattened by the blast.

Miller told CTV Newsnet early Monday evening that an intial investigation into the disaster will take "days, if not weeks."

A report on the explosion and its aftermath won't be ready for several months, Miller said.

CTV Toronto confirmed Monday evening that Toronto police are also investigating the incident.

Surveying the impact

Monday morning, business owners returned to their shops to survey the damage. There were reports several stores were looted during the evacuation but Toronto police have not arrested any suspects.

A Value Village store in the area had all the front windows blown out.

Further down the neighbourhood, Joe Mauko, a local photographer, returned to his studio to find all the windows of his store and the neighbouring shops were shattered to pieces.

"I've got a walk-through window right now," he said, adding he's thankful that none of his equipment was damaged.

"I was more concerned about my equipment and theft," he said.

Mauko said he wasn't too surprised at the extent of the damage to his studio. He went to look for his mom shortly after the blast Sunday and said he could feel the heat and force of the explosion from Dufferin Street and Wilson Avenue.

"It was unreal. Unreal," he said.