The investigation into the fatal fire on Gray Avenue in Staunton on July 10 found the cause was improperly discarded smoking materials.
There were no working smoke alarms in the home.
Bruce W. Shott, 62, died in emergency surgery from injuries sustained in the fire.
The determination from the Fire Marshal was released today.
Staunton Fire & Rescue as well as Augusta County Fire-Rescue offers free smoke alarms to residents. Contact your local fire department for more information.