All plastics (polymers) degrade at sufficiently high temperatures, producing fumes with various hazards. Those materials presenting hazards at lower temperatures are discussed here.
A document which covers general and specific hazards and risks in darkroom work, guidance on how these can be managed and such safeguarding issues as might apply.
GL101 - An introduction to GHS/CLP chemical hazard labelling
Describes the hazard labelling to be introduced by 2015 for all chemicals, as a consequence of the Global Harmonised System for such labelling. Explains what the new labels will look like, and what information they will include.