The owner of a Vancouver restaurant ripped apart by a massive explosion said she could not think of any reason why someone would set fire to her establishment.

Taco Del Mar owner Manjeet Nandha says she was shaken up after learning about the fire and explosion early Wednesday morning. CBC

Manjeet Nandha told CBC News Wednesday she never encountered any trouble while operating Taco Del Mar at 680 West Broadway for the past three years. She added that she never had any problems with staff.

"I was shaken up," she said. "I got a call this morning about four or six [o'clock]. My husband picked up the phone and all he [understood] is there [was] a fire in the Starbucks and the Taco Del Mar," she said.

Vancouver police spokesman Const. Tim Fanning confirmed that the Wednesday morning fire was set deliberately. It resulted in an explosion that destroyed the restaurant and a coffee shop, and damaged several other businesses.

A Starbucks coffee shop and the Taco Del Mar restaurant were destroyed by Wednesday morning's blast, but nobody was injured. CBC

"The fire was set inside Taco del Mar … at about 2:30 a.m.," he said.

"The explosion was an air/fuel explosion. I can't tell you what type of accelerant was used. There's a lot of forensic work to be done.

"An arson investigation is very, very scientific so they [investigators] have to go through all the evidence, use science labs," Fanning said.

Vancouver firefighters and police arson and forensic investigators combed the area around West Broadway and Heather Street all day Wednesday. Crews were kept busy bulldozing debris and shattered glass littering the streets and sidewalks. Shattered glass covered nearly half of the 600 block of West Broadway following the explosion. CBC

"When something such as gasoline ignites in the air, it makes a huge explosion," Fanning said. "[For] any large fire, if there's a lot of accelerant there, it can cause a large explosion."

Witnesses said the explosion created a fireball that engulfed the taco shop and neighbouring Starbucks.

"We panicked," said Suleyman Kucuk, an eyewitness. "Is it a bomb, or it's an earthquake or what's going on?"

Witness Lesley Jackman said: "The flames were almost completely across the road. They were probably 15-feet high and all you could see was the fire."

A CBC viewer submitted this photo after the explosion Wednesday morning on West Broadway. Submitted by Lesley McKnight

Two other witnesses told CBC News that immediately after the explosion, they saw a man dressed in dark clothing running from the area. It is not known whether the man was fleeing the explosion or was involved in the incident.

"We will be following up all leads. We'll be looking at any video that may show people coming and going around that area last night, any time before or after 2:30 a.m.," Fanning said.

Windows shattered in neighbourhood

Windows were shattered at several businesses in the area, including the London Drugs store across the street.

The explosion also blew in a sixth-floor window at the Holiday Inn half a block away, in the room where a member of the Canadian military was staying. The hotel manager said the woman was not injured by the glass, but was shocked by the explosion.

At least five businesses were damaged by the explosion and police said it was a miracle no one was hurt.

West Broadway was closed between Ash and Willow streets for much of the morning, but traffic had returned to normal on the busy crosstown route by noon.