There are no reports of injuries to people.
Fire Chief John Farrington says about 12 dogs were rescued from the Cape Cod Animal Hospital but a few animals are missing. He doesn't know how many were in the building in Barnstable, about 5 miles north of the Kennedy family's Hyannis Port home.
Neighbor Ken Lacasse tells the Cape Cod Times vet Scott Munson broke the kennel door with a cinder block.
Firefighters say Monday night's explosion came 20 minutes after area residents reported their lights had dimmed. Investigators are trying to determine if natural gas caused the blast.
Representatives of the National Grid utility rushed to the scene. So did people trying to find their pets.