MINNEAPOLIS (WCCO) – Excelsior Fire officials and the State Fire Marshal’s office concluded Tuesday that a house explosion and fire that destroyed a Tonka Bay home was likely caused by a heating lamp being used for newborn puppies and was not a house explosion.

The fire happened at about 3:55 p.m. Monday on the 100 block of Lakeview Avenue.

No one was in the house, which is home to Scott and Michelle Schmitt and their six children, when the fire happened, authorities said.

But when the Schmitts arrived at the scene, they said their five black Labrador retrievers were in the house when it caught fire. Only one dog, a puppy, survived.

The Schmitts said their black lab gave birth to puppies on Friday.

Authorities said the fire was caused by a heating lamp that was attached to a whelping box in the garage to contain those puppies. Fire officials said the heat lamp likely caused the materials that were in the box, including a whelping mat and other materials to keep the puppies warm, to ignite. The fire then spread from the garage to additional parts of the home.

Neighbors said Monday they heard several explosions at the home during the fire. Officials said those were caused by propane cylinders in the garage and other combustible materials that contributed to the fire spreading.