Degradable / Oxo-degradeable Oxo-degradable plastics are conventional plastics made from petrochemicals. The difference is that oxo-degradable plastics have small concentrations of additives (usually metal salts) that cause them to degrade at an accelerated rate. These plastics will usually be labeled as ‘degradable’, ‘oxo-biodegradable’ and sometimes even ‘biodegradable’ or ‘oxo-biodegradable’.