CORRECTION: A previous version of this story attributed details about the woman killed in the explosion to a spokesperson for air ambulance service Ornge. Ornge does not have any details of the woman’s age or identity.

Investigators still don’t know what caused an explosion in Kitchener, Ont., that left a woman dead and a man with serious injuries on Wednesday.

Kitchener fire chief Jon Rehill said firefighters were called to the home on Sprucedale Crescent at 8:10 a.m. in response to a reported explosion.

Emergency crews arrived at the scene to find a woman dead and a man seriously hurt. An air ambulance was brought in to take the man to a trauma centre in Hamilton.

Jamie Compton says he was driving through the neighbourhood when he saw smoke. As he got closer to the inferno, he heard screams for help.

Compton says he helped get the injured man to the street but couldn’t do anything to assist the woman.

“We (saw) her lying there and we didn’t know what to do,” he told CTV Kitchener.

Ellen Hergott, who lives nearby, said she heard a “huge explosion” and glass shattering. She went outside thinking a tree had fallen, and soon realized she could see black smoke from her front yard.

Hergott told CTV News Channel that she walked over to the explosion site and talked to the injured man as he waited for an ambulance to arrive.

“He was alert. He was breathing. He opened up his eyes. He did not respond to me,” she said.

According to Hergott, the man was bleeding from the back of his head and had obvious burns on his head, hands and feet.

Police said late Wednesday morning that they had not been able to identify the man or the woman.

Neighbour Sam Bailie said that an older couple with two children lived in the home, and that their older son had moved out several weeks ago. “I feel sorry for them,” he said.

Rehill said that 16 houses “will need to be evacuated for up to three days” and that “there are two significantly damaged homes that people will not be able to get back into for a long period of time.”

As of Wednesday afternoon, firefighters were still dousing hotspots and the Office of the Fire Marshal was on scene to begin an investigation.

“There is no preliminary word on the cause,” Rehill said.

Waterloo Regional Police deputy chief Kevin Chalk said Wednesday afternoon that police were conducting a death investigation and that an autopsy would take place in the next two days.

“Although we have received some information, it hasn’t transitioned as yet to a criminal investigation and we don’t know if in fact that will occur,” Chalk said.

He said it is unclear whether the deceased woman and injured man were outside when the explosion happened or were “blown outside.”

Heavy rain was moving through the area around the time of the explosion, and several neighbours reported hearing thunder and seeing lightning.

Neighbours told CTV Kitchener that they heard the explosion and ran outside to find drywall and other debris raining down.

“I heard a very loud rumbling – it was like intense thunder. Within about a second or two, there was a very loud explosion,” said Rick Berenz. “I actually had thought that an airplane had crashed in my backyard.”

Much of the debris landed on the street. Some of it also appeared to have landed on parked vehicles, causing damage.

People living as far as six blocks from the explosion site reported feeling their homes shake.

City councillor Bil Ioannidis said he and his family heard the explosion from their home.

“We heard this big bang and we were like ‘Wow, what was that?’” he told CTV News Channel, adding that the scent of smoke continued to permeate the neighbourhood more than an hour later.

Kitchener Mayor Berry Vrbanovic thanked first responders for their efforts and said members of the public can contact victim services if they need assistance.

“An event of this magnitude is significant and traumatic for those directly impacted, as well as the community and the neighbourhood as a whole,” the mayor said.

With reports from CTV Kitchener's Max Wark and Christina Succi

Investigation is ongoing into house explosion on Sprucedale Crescent in Kitchener that occurred this morning. Members from the Ontario Office of the Fire Marshal @OntarioWarnings, @ROWParamedics, @WRPSToday, @KWHydro, @CityKitchener @KitchFire are on scene. pic.twitter.com/8Yfr4i9Mc9 — Waterloo Reg. Police (@WRPSToday) August 22, 2018

Debris all over the road in front of the house on Sprucedale Cres. that exploded and caught fire this morning. pic.twitter.com/UJFmuFsSNg — Krista Simpson (@KristaSimpson) August 22, 2018