incombustible (usu. waste)

Exploration Stage: Burned-out Estate
From: Mr. Black
Description: I am going to have a headache. Mr. Magill. We still don't know why the iron exploded, but it may be that sparks flew to the carpet and started the fire. We need to pursue this possibility. Find the remains of the burning carpet. See how quickly it ignites.
Completed: This is getting more and more interesting. As far as I can see the carpet is not burning, rather than the way it burns, it must have been treated with fire retardant to make it more fire resistant than the others in the mansion. It seems that the people who live here really know a lot about fire.