Marlene Mumford, 84, and William Mumford, 90, died at their property on Hoel Fawr, Caerphilly, on 12 December 2025. The inquest in Newport was told that the most likely cause of the fire was a mechanical or connection failure with the gas heater. Assistant coroner Sarah Le Fevre said it was believed William Mumford had attempted to carry the cylinder out of the home to remove it, but that this had caused the flames to spread. She recorded the deaths as an accident, the result of an "unintended act with unforeseen circumstance".
The alarm was raised by a neighbour at the nearby Tyler's Arms who noticed smoke and large flames. He and another man ran to the house and saw a gas canister explode near the front porch, with flames rising above the height of the house. Emergency services could not initially enter the property due to the extent of the damage. Firefighters reported thick, black smoke "pumping out" of the property. The couple were pronounced dead at the scene.