A nearby wooden bungalow was refurbished and the insulation improved with Celotex a few years ago. I wonder if the occupants know that was the stuff on the outside of Grenfell tower that burns at high temperatures and gives off toxic fumes.
I have considered putting some Celotex in my attic and then covering it with thin plywood so that I could walk on it but I have rather gone off the idea, though if the house catches fire badly, I am unlikely to want to go in the attic.