The explosion was reported as a house fire in the 1000 block of Delta Street just after 5 p.m. Monday. The investigation remained ongoing on Tuesday.

The incident “displaced” the exterior walls of the two-story home and caused significant damage to the structure, Guido Concello of the Redding Fire Department said in a statement released Monday evening.

This also prompted a visit from construction officials to assess the safety of the structure.

When Redding firefighters first arrived on scene, they saw no smoke or fire from outside. When they examined the inside of the building, they found a small, smoldering fire in a bedroom and obvious signs that something had exploded, according to the statement.