One of my favorite proverbs goes: The optimist says the cup is half full, the pessimist says half empty, but the engineer asks, "How much is in the cup?"
I just read about a recent confirmation that "liquid styrene" may be a carcinogen. Not surprised, but not worried either. What worries me more is that people will add "poly-" to this material and see this news as reinforcement of their fear and loathing of polystyrene, especially foam polystyrene food/beverage packaging.
Styrene is the monomer for polystyrene, of course, and as such is a building block for this plastic, just as vinyl chloride is a building block for PVC, and BPA and phosgene are building blocks for polycarbonate. There should be no monomer left when polystyrene is made, likewise for PVC and PC. But people still confuse building blocks with additives, and think that the plastics have these offensive materials "in them" as ingredients.