There is a considerable knowledge gap regarding the long-term fate of plastics in the environment. Acknowledging this gap, in the context of life cycle assessment methods, is critical to account for the long-term fate of plastics in the decision-making process. Ignoring the long-term potential for environmental and health damage from plastic particles makes it difficult to defend a quantitative environmental assessment comparing fossil-based conventional plastics with other alternative materials. This Review highlights that the addition of a plastic particulate footprint as a midpoint impact indicator in life cycle assessments should be considered to quantify these overlooked long-term impacts