CALLAWAY COUNTY -- A house explosion that killed a Callaway County mother and her infant son was caused by a propane gas buildup.

Investigators said the buildup was underneath the home after the capping on an old pipe corroded. Investigators said the gas was finally ignited by the stove in the kitchen.

The visitation for 20 year old Amber Smith and her 4 month old son Simon scheduled for today from 5-7 at Maupin Funeral Home in Fulton. The funeral services are scheduled for tomorrow.

Smith's husband was not home at the time of the blast, but a trust fund has been set up in his name at the First Assembly of God in Fulton.