Plastics vary widely, including polyethylene terephthalate (PET), high-density polyethylene (HDPE), and polystyrene (PS). PET bottle degradation can take 450 years; HDPE bottles, 100 years; and PS foam, over 50 years. Biodegradable plastics, like polylactic acid (PLA), can degrade within 6 months to 2 years under industrial composting.