[CosmicCreature]

Most Plastics Have A melting point rate above 200 F .In order to release toxic fumes it would have to reach minimum melting temp.
Even still good ventilation is nice idea if you have a wide variety sourced from allover or older products.
Ive had few older mcfrlanes figures that had a strange paint odor when I opened them after being sealed for a decade or more . None of them smell that way after airing out regularly. But I do still have few that feel sticky ,like oil bleeding out the paint .

link has graphs with info on varying properties for common plastics
https://plasticranger.com/7-types-of-plastics/