Towards circularity: New database maps hazards and diversity of plastic chemicals to support route to safe, sustainable plastic economy

Plastics and their constituent chemicals are rapidly entering the environment, degrading ecosystems and impacting human health. EU plastics policy recognises this as a significant risk; it seeks to tackle pollution and marine litter and facilitate a circular plastics economy as part of the Plastics Strategy, the Circular Economy Action Plan, and specific policies targeting biobased, biodegradable, compostable, single-use plastics, plastic packaging and waste. Additionally, in 2022, the United Nations Environment Assembly began negotiating a new legally binding instrument to address the full lifecycle of plastics, with the aim of ending plastic mismanagement and pollution via international cooperation. 

In addition to the problems of macro and micro-plastic pollution, plastics contain a complex mix of chemicals that are considered harmful for human health and ecosystems and have been linked to reproductive, neurodevelopmental, immune, and metabolic disorders. For example, as well as their constituent polymers, plastics may contain additives such as phthalates and bisphenols – known endocrine disruptors. These chemicals, along with microplastics, are released into the environment as products are manufactured and used. Processing and treatment of plastic waste also releases chemicals. Re-using plastics is also problematic because older materials degrade, increasing the risk of chemical release. 

While data exists on the contents and risks of plastic chemicals in certain products such as toys and food packaging, a more comprehensive assessment of plastic ingredients and their hazards is needed, say the authors of a new study. This could help policymakers to enact effective regulation and potentially facilitate the design of safer plastics that leach fewer chemicals. 

At present, information on hazardous plastic chemicals is siloed, domain-specific (e.g. in toys), focused on chemicals that are intentionally added, or lacking relevant detail on hazard. However, policy solutions are underway to address this challenge. In November 2025, the Council of the EU formally adopted the ‘one substance, one assessment’ (OSOA) package, aiming to streamline EU assessment of chemicals and their risk and to create a new common data platform as a one-stop shop for chemical information – crucial for better, faster protection of both human health and the environment.

This study takes a broad approach, presenting a global inventory of known plastic chemicals with data on their properties, presence, and regulation, identifying chemicals of concern and assessing whether these are persistent, toxic, or bioaccumulative.

The researchers identify and collate 16,235 chemicals that are either intentionally or unintentionally present in plastics to form their inventory, named PlastChem. Most are discrete compounds with known structures (12,658), spanning inorganic, organic and organometallic chemistries, and a wide range of physicochemical properties. Many (3,667), however, lack defined chemical structures and properties, or offer limited information on their constituent compounds.

The inventory describes additives (5,776), processing aids (3,498), starting substances (1,975) and non-intentionally added substances (e.g. impurities and reaction by-products; 1,788). Additives – coolants, fillers, plasticisers, etc. – are the most diverse class, while many substances fulfil different functions at different stages of the plastic lifecycle, highlighting their structural and functional diversity.

The researchers also identify chemicals of concern – those which are persistent, bioaccumulative, mobile, and toxic. Chemicals of concern are associated with all major polymer types, including fossil- and bio-based plastics. These chemicals represent one-quarter of recognised plastic chemicals (4,219), and most are classified as toxic (overall, to the aquatic environment, to human health, or to specific organs or biological systems). Over 10% of polymers themselves – substances believed to pose no serious risk due to their large molecular weight – are classified as hazardous. 

The researchers group more than 10,000 of the chemicals in PlastChem by structural similarity. This returned 28 similar groups with at least 10 members in each. Over 75% of chemicals of concern belong to just three groups: aromatic amines, aralkyl aldehydes, and alkylphenols.

Almost one-third (30%) of compounds marketed for use in plastic production, detected in plastics, or shown to be released from plastics (into foodstuffs, for instance) contain chemicals of concern. This highlights how many are either intentionally or unintentionally present in plastics throughout the production process, raising their exposure potential. Additionally, most chemicals of concern are unregulated globally, despite these substances being globally traded in the form of chemicals, materials, products, or waste. While some are regulated nationally, implementation and oversight varies significantly, highlighting a substantial gap in governance and, therefore, potential for harm.

Finally, the authors discuss pathways to creating safer plastics. The first step towards safety could involve removing and replacing known chemicals of concern with safer alternatives, while also investing in the design and development of innovative solutions, with incentives for their adoption¹.

The researchers acknowledge that their assessment was limited to chemicals that have already been assessed for toxicity, and to hazards identified in chemical registries, rather than in wider scientific literature. They highlight that complete or conclusive data was not available for many chemicals, and that absence of evidence should not be confused with evidence for absence of harm. 

These data gaps should be remedied by an increase in transparency, suggest the researchers: manufacturers should publicly disclose product data. Greater transparency in chemical information is something that will be addressed by the aforementioned OSOA package. Additionally, production processes could be optimised to avoid introducing hazardous substances unintentionally. The range of plastics produced could also be simplified in terms of number and molecular complexity, given the improbability that scientists and regulators can determine potential hazard in many thousands of chemicals in a timely way. The study recommendations focus on improving the safety of plastics in terms of their production, design, and assessment, envisaging routes to a non-toxic circular plastics economy; as such, it does not make recommendations for the processing and treatment of plastic waste.

Footnotes:

1. There are hurdles with such action – for example, certain functions where hazardous chemicals are especially prevalent and difficult to substitute, such as heat and light stabilisers – but it is in-line with frameworks such as the European Commission’s ‘safe and sustainable by design’, a voluntary approach to guide the innovation process for chemicals and materials.

Reference:

Monclús, L., Arp, H.P.H., Groh, K.J., Faltynkova, A., Løseth, M.E., Muncke, J., Wang, Z., Wolf, R., Zimmerman, L. and Wagner, M. (2025) Mapping the chemical complexity of plastics. Nature 643, 349–355. https://www.nature.com/articles/s41586-025-09184-8