A two-story duplex caught fire Thursday night near Sumner, prompting the occupants to evacuate the house.

East Pierce Fire and Rescue responded to the blaze on the 8400 block of 143rd Avenue Court East just after 10 p.m. The agency was joined by firefighters from Central Pierce Fire and Rescue and Orting Valley Fire and Rescue.

A stack of cardboard boxes and packing material had been placed closely to a baseboard heater in the kitchen, apparently causing them to ignite and start the fire, according to investigators.

When firefighters arrived, smoke and flames were visible from the house.

The lower unit’s residents had managed to escape the house without injury, but at the cost of all their material belongings. The upstairs unit was unoccupied.

Estimated damage to real and personal property was $70,000.