Fire crews say it was lucky no-one was hurt when an explosion blew the doors off a pizza restaurant on Lygon Street in Carlton.

The shop's owner was fumigating pests with an aerosol can when the can caught on a pilot light and exploded about 10:00am (AEDT).

The explosion has ruined the kitchen and blown the doors off their hinges, showering the street with glass.

Nobody was hurt but fire crews estimate the damage will cost about $100,000.

Dario D'Agostino was walking past the shop at the time.

"It was just like a big bomb exploding. The door came off, so I was in front of the door, like two metres, very close," he said.

Metropolitan Fire Brigade Commander Darren McQuade says it is lucky the usually busy street was quiet.

"It is quite remarkable that no-one's been injured in an explosion of this kind. He was very lucky to get out uninjured," he said.

Commander McQuade says people should read the instructions before using aerosol cans.

"It's obviously unusual to get an explosion of this kind, however the aerosol cans that we're speaking about have been causing a few problems around the country, so our fire investigation unit will come and have a look as well," he said.

"It is a warning to follow the instructions on the can and make sure that all ignition sources are turned off prior to using these fumigation devices."