Oxo-biodegradable means that the plastic (generally a conventional fossil-fuel-based polymer) has an additive that speeds up the degradation process (a pro-oxidant), causing the plastic to break down into smaller particles, especially when exposed to heat or light.
There is no explicit time frame associated with this term and no assurance that the smaller particles will completely biodegrade in a timely manner. In the meantime, these micro or nano-sized plastics become even more bioavailable to wildlife. Oxo-biodegradable products cannot be composted, and they negatively impact the recycling stream by reducing the structural integrity of the final product. Therefore, products labeled as oxo-biodegradable do not provide an effective level of plastic pollution prevention.