OXO-biodegradation is biodegradation as defined by the European Committee for Standardization (CEN) in CEN/TR 1535–2006, as 'degradation resulting from oxidative and cell-mediated phenomena, either simultaneously or successively'. This degradation is sometimes termed 'OXO-degradable', but this latter term describes only the first or oxidative phase of degradation and should not be used for material which degrades by the process of OXO-biodegradation as defined by CEN. The correct term is 'OXO-biodegradable'.Sufficiently quick biodegradation is in particular not demonstrated for landfills and the marine environment. A wide range of scientists, international and governmental institutions, testing laboratories, trade associations of plastics manufacturers, recyclers and other experts have therefore come to the conclusion that oxo-degradable plastics are not a solution for the environment and that oxo-degradable plastic is not suited for long-term use, recycling or composting. There is a considerable risk that fragmented plastics will not fully biodegrade and a subsequent risk of an accelerated and accumulating amount of microplastics in the environment, especially the marine environment. The issue of microplastics is long acknowledged as a global problem in need of urgent action, not just in terms of clean-up of littering, but also of plastic pollution prevention.It is no longer tenable to conclude that there is 'no firm evidence either way' whether oxo-biodegradable is effective. I consider that recent research provides clear and compelling evidence that oxo-biodegradable plastic is indeed effective in facilitating very significantly speedier degradation than is the case when that technology is not used.... cannot imagine that such significantly speedier final degradation occurs later than 'within a reasonable time', however that the expression might be defined.... 'fanciful and unreasonable'. OXO-biodegradation is biodegradation as defined by the European Committee for Standardization (CEN) in CEN/TR 1535–2006, as 'degradation resulting from oxidative and cell-mediated phenomena, either simultaneously or successively'. This degradation is sometimes termed 'OXO-degradable', but this latter term describes only the first or oxidative phase of degradation and should not be used for material which degrades by the process of OXO-biodegradation as defined by CEN. The correct term is 'OXO-biodegradable'. There are two different types of biodegradable plastic: It is important to distinguish between 'oxo-degradable' plastics, which fragment but do not biodegrade except over a very long time, and 'oxo-biodegradable' plastics, which degrade and then biodegrade. The European Committee for Standardisation (CEN, for Comité Européen de Normalisation) has established the following definitions, in TR 15351: