3D-printed PLA disintegrated more than 90 percent after 12 weeks of industrial composting, while injection-moulded PLA of the same material reached only about 54 percent. A blanket biodegradable claim on a PLA product says nothing reliable about whether that specific item will actually break down.
An open-access 2026 RSC Sustainability study from Dublin City University tested identical PLA feedstock formed two ways, by 3D printing and by injection moulding, then ran both through industrial composting conditions for 12 weeks. The difference in how the part was made, not what it was made of, decided whether it broke down.
