HAMILTON, Ontario (AP) _ An explosion leveled a two-story apartment building today, injuring seven people and burying at least two. Police did not expect to find survivors in the rubble.

The blast, apparently caused by a natural gas leak, caused four apartments to cave in on a delicatessen.

Lt. David Cossette, a fire department spokesman, said two people were thought to be trapped under the debris.

''There's no chance they'd be alive right now,'' he said.

Mike Mojsilovich, owner of dry cleaners next door, said he had just stepped out of his store when the explosion occurred. The force of the blast knocked him back into the building.

''Bricks were flying all over,'' he said. ''I slipped and I ran.''

''I saw a man with his skin falling all over. He came into my store and asked me to pour cold water all over him. I hosed him down.''

Mojsilovich said he and other merchants in the area smelled gas about a half-hour before the explosion. Police said the blast was apparently caused by natural gas.