Some types of faux leather are very bad. PVC leather is environmentally damaging for a number of reasons. The dioxins it contains are toxic to humans and environmentally damaging if burned. Flexible PVC contained phthalates, which are carcinogenic and believed to disrupt the endocrine system
Polyurethane (PU) leather is not as bad, but the manufacturing process uses toxic chemicals such as dimethylformamide. This compound has been linked to birth defects.