While often confused with biodegradable plastics, oxo-degradables are a category by themselves. They are neither a bioplastic nor a biodegradable plastic, but a conventional plastic mixed with an additive in order to imitate biodegradation. Oxo-degradable plastics quickly fragment into smaller and smaller pieces, called microplastics, but don’t break down at the molecular or polymer level like biodegradable and compostable plastics. The resulting microplastics are left in the environment indefinitely until they eventually fully break down.