All textile products are subject to some finishing steps, in order to functionalize their ultimate function into a destined final product. These steps include adding colour with dyes (either reactive and integrated inside the fibres or coated on their outside), and/or adding other properties, including to help with fast drying (by making fibres hydrophobic) or with UV protection (by adding silver nanoparticles, for example). These chemicals are added directly to “virgin fibres”, whether natural or synthetic. This functionalization step is mainly completed by the textile industry making the final product, as opposed to involve the fibre-making industry at the source of the fibres. For natural fibres, which are known to biodegrade readily in the environment, the question arises on whether such additives can alter, to the point of preventing, the biodegradation process itself. This would turn natural biodegradable fibres into somewhat synthetic materials (from the circularity standpoint), which clearly would be a problematic situation. In this study, we assessed the biodisintegration of nonwoven natural material with various additives under experimental marine conditions, with biodisintegration referring here to the initial steps of biodegradation, thus the breaking apart of material, but not necessarily down to the level of molecular carbon. As of today, while the experiment is still on-going, our results show that the biodisintegration of natural material can be up to 10x slower with certain additives. In the presentation, we will detail the final outcome of the experiment, and the details about the additives and their difference on how they behave in seawater. It can already be concluded however that additives have a significant effect on the biodisintegration process, and thus on the ability of natural fibres to readily (and maybe fully) biodegrade in the environment.