What is an OXO biodegradable material? OXO- biodegradable plastics use a process called oxidation to break down plastic more quickly than conventional plastics. OXO plastics are manufactured with an additive that accelerates the oxidation process. When the plastic undergoes oxidation, it breaks down into small pieces under heat, light or mechanical stress. Microorganisms can then consume these fragments and break them down into natural substances such as water, carbon dioxide and biomass