wrote in message news:a170aee7-bbc6-492f-aebc-

"When burned without enough oxygen or at lower temperatures (as in
a campfire or a household fireplace), polystyrene can produce
polycyclic aromatic compounds, carbon black, and carbon monoxide, as
well as styrene monomers." (wikipedia) Those are some nasty things
to breath.

Well duh, everything burning is bad to breath. My point it that it is no
more a danger than any other product in the typical house. Carpet, drapes,
upholstery can be much worse. The insulating value far outweighs any other
consideration.