Do we really know the environmental impacts of chemical recycling of plastics?

Over the past decade, research into chemical recycling (CR) of plastic waste has gained significant traction. Simultaneously, life cycle assessment (LCA) has become an increasingly crucial tool for evaluating the environmental impacts of materials, products, and processes. This review provides a critical overview of the current research landscape. It highlights the ambiguity surrounding nomenclature, where ‘chemical recycling’ and ‘feedstock recycling’ are often used interchangeably to encompass the several waste plastic conversion processes. This can lead to unclear comparisons between CR and mechanical recycling (MR) processes. This critical analysis of major technical papers on CR revealed the common pitfalls of CR LCAs. Direct comparisons between CR and MR and between chemical processes and conventional incineration are now considered obsolete, given the variety of chemical processes and feedstocks available. CR complements MR by recovering plastic waste that is not amenable to MR, hence the need to specify the wider context. To establish a fairer and more comprehensive assessment of CR methods, and support its policy integration, further research on processing of plastic waste is imperative. This paper provides recommendations on how to expand the data pool and improve the assessment of the real environmental benefits of CR.