EDMONTON -- Fire investigators have determined the cause of a blaze that destroyed a north Edmonton home and resulted in damage to four neighbouring houses Tuesday morning.

Emergency crews received more than 20 calls just before 7:30 a.m. Tuesday for the house fire near 137 Avenue and 37 Street.

According to Edmonton Fire Rescue Services' communications advisor, Brittany Lewchuk, investigators have determined the fire was caused by "improperly discarded smoker's material."

EFRS investigators believe the fire originated in the now-destroyed home's attached garage.

Ethyl Fiddler and her friend Teresa lived in that home.

She said they were getting ready for work when the fire started.

"I smelt smoke, and just as I was getting upstairs and she was standing by the garage door and she had it open and just a big thing of smoke come flying in, it was so fast," said Fiddler.

"I know Teresa is so devastated."

Fiddler says this fire is serving as a tragic reminder for smokers to be very vigilant when disposing of cigarettes.

"Please don't smoke in your garages, and if you do, have something really long like a big, big ashtray."

Damages are estimated at $1.2 million, with $1 million worth of damage to the five homes, and $200,000 to the contents.

No injuries have been reported.

A total of seven fire crews – roughly 30 firefighters – responded to the north-end fire.

The blaze was deemed under control by 9:13 a.m. and fully extinguished by 3:13 p.m. Tuesday.

EFRS are reminding the public to exercise caution when smoking, in order to prevent incidents like Tuesday's.