Impact statement

In advance of Intergovernmental Negotiating Committee (INC-5.2), we highlight the urgency and importance of fully incorporating plastics-associated chemicals of concern in the final treaty text. Their widespread hazards to human (Symeonides et al., Reference Symeonides, Aromataris, Mulders, Dizon, Stern, Barker, Whitehorn, Pollock, Marin and Dunlop2024) and environmental health (e.g., Giroux et al., Reference Giroux, Siddiqui and Brander2024) are well established: they pose a threat to several United Nations Sustainable Development Goals (Brander et al., Reference Brander, Senathirajah, Fernandez, Weis, Kumar, Jahnke and Hartmann2024) and have already exceeded planetary boundaries (Persson et al., Reference Persson, Carney Almroth, Collins, Cornell, De Wit, Diamond and Hauschild2022).

Hazards, health and environmental concerns

Considering the large number (over 4,200) of hazardous chemicals in plastics, many toxicity mechanisms or targeted functions are at play (Wagner et al., Reference Wagner, Monclús, Arp, Groh, Muncke, Wang, Wolf and Zimmermann2024; Wiesinger et al., Reference Wiesinger, Parkinson, Geueke, Boucher, Cabane, Zimmermann and Muncke2025). Almost 1,500 plastic chemicals are carcinogenic, mutagenic, or toxic to reproduction. Some plastic chemicals are endocrine-disrupting chemicals, while others (over 1,700 chemicals) may adversely affect specific organs or systems after repeated exposures. In addition, over 2,700 chemicals of concern are known to be toxic to aquatic organisms, and over 450 chemicals are persistent, bioaccumulative and/or mobile. This highlights that many plastic chemicals are not only a concern for human health but they can also present serious and lasting negative consequences for ecosystems.

The financial consequences of ecosystem disruption by plastic chemicals are not easily assessed, while costs to society associated with adverse human health outcomes of plastic chemical use (Trasande et al., Reference Trasande, Krithivasan, Park, Obsekov and Belliveau2024) and other economic costs of plastic pollution (Beaumont et al., Reference Beaumont, Aanesen, Austen, Börger, Clark, Cole and Wyles2019) can be estimated. Plastic chemicals are linked to cancers, infertility, neurodevelopmental disorders, and cardiovascular and metabolic diseases like obesity and type 2 diabetes (Symeonides et al., Reference Symeonides, Aromataris, Mulders, Dizon, Stern, Barker, Whitehorn, Pollock, Marin and Dunlop2024). Recent converging estimates of both direct (medical) or indirect (productivity loss) costs for some plastic chemicals (bisphenol A [BPA], selected per- and polyfluoroalkyl substances, phthalates and polybrominated diphenyl ethers, among other chemicals) ranged from 250 to 675 billion USD yearly for the United States (Landrigan et al., Reference Landrigan, Raps, Cropper, Bald, Brunner, Canonizado and Dunlop2023; Trasande et al., Reference Trasande, Krithivasan, Park, Obsekov and Belliveau2024). These examples demonstrate that regulating chemicals of concern in the treaty would deliver substantial health and economic benefits. For instance, a regulation of BPA in all plastics could prevent up to 61,800–66,400 children annually (82–88% of cases) from developing childhood obesity in the United States and European Union and save associated health costs of 3.6–3.9 billion USD. In contrast, a phase-out of BPA in the specific products currently considered in the treaty text, such as toys, would only prevent 11–27% of childhood obesity cases (Scientists’ Coalition for an Effective Plastics Treaty, 2025).

The example of BPA highlights the issue of regrettable substitution: BPA was replaced by structurally similar chemicals, for example, Bisphenol S, with equal or even more severe effects on health than BPA (Wu et al., Reference Wu, He, Sun, Zhang, Yang, Liu, Zhou and Jiang2025). Therefore, it is crucial that chemical management that is protective of health and the environment avoids regrettable substitutions. The most effective way of ensuring this is by regulating chemicals as groups. For example, instating phase-outs on all bisphenols and exemptions for specific members of chemical groups only if reliable data can show the absence of hazard properties for a specific compound. Such exempted compounds are used in controlled environments and are not present in end-applications and/or are essential, and alternatives are not yet available.

Apart from their direct effects on human health, plastic chemicals can also have indirect effects on health as evidenced by effects on animal health (e.g., through contamination of the food chain) and ecosystem health (through reduced or impaired ecosystem services). Apart from (or in addition to) their direct effects on human health, plastic chemicals can also have indirect effects on health through their effects on animal health (e.g., through contamination of the food chain) and ecosystem health (through reduced or impaired ecosystem services). The chemical N-(1,3-dimethylbutyl)-N’-phenyl-p-phenylenediamine (6PPD) is commonly used in tire rubber as an antidegradant. 6PPD exemplifies the need to consider health through the prism of “One Health,” which recognizes that the health of humans, animals, plants and the environment are interconnected and interdependent. After substantial analytical work, Tian et al. (2021) identified 6PPD, or more specifically its quinone derivative, as the plastic chemical responsible for the mass death of coho salmon and toxicity to other salmonid species (Greer et al., Reference Greer, Dalsky, Lane and Hansen2023; Mayer et al., Reference Mayer, Moran, Miller, Brander, Harper, Garcia-Jaramillo and Carrasco-Navarro2024). The Washington State Department of Ecology has identified several populations affected by 6PPD, including Indigenous Peoples, and populations with higher fish consumption, such as subsistence fishers from low-income communities or communities of color, and people working in or living near tire manufacturing facilities or exposed to artificial turf. The Department of Toxic Substances Control (DTSC) from California has estimated that the loss of coho salmon has significantly impacted their Native American Tribal Nations. Beyond cultural loss, DTSC has paralleled the decline of the salmon fishery and the increase in disorders or disease in the Karuk Tribe in the Klamath Basin, inducing a yearly health cost of about 1.9 million USD (Bass, Reference Bass2024; Morales, Reference Morales2024).

It has been shown that early life stages (embryos in utero and children), as well as people of reproductive age, are particularly sensitive to several plastic chemicals. This highlights the need to protect these subpopulations, as developmental exposures can lead to diseases and disorders later in life. In addition, frontline and fence line communities (including waste workers and Indigenous Peoples) constitute other vulnerable populations, who are particularly chronically exposed to hazardous plastic chemicals. In addition, the use and presence of hazardous chemicals in plastic products poses a significant challenge to achieving a toxic-free and sustainable circular economy. Such chemicals undermine circular strategies, such as safer and more sustainable reuse, repair, repurpose, remanufacture and recycling. For instance, legacy substances that were widely used in plastic products, such as hexabromocyclododecane, hinder safer and more sustainable reuse of plastic products in their entirety (Wagner and Schlummer, Reference Wagner and Schlummer2020).

Furthermore, chemicals raise a variety of safety concerns for mechanical recycling, which is the most commonly applied recycling technology. Mechanical recycling can delay the phase-out of legacy substances and increase risk to human exposure when they are reintroduced into new products, such as food packaging and artificial turf (Mayer et al., Reference Mayer, Moran, Miller, Brander, Harper, Garcia-Jaramillo and Carrasco-Navarro2024; Wiesinger et al., Reference Wiesinger, Bleuler, Christen, Favreau, Hellweg, Langer, Pasquettaz, Schönborn and Wang2024). Brominated flame retardants in electrical and electronic products can be recycled and introduced into consumer goods like toys and kitchen utensils (Hahladakis et al., Reference Hahladakis, Velis, Weber, Iacovidou and Purnell2018). Harmful plastic chemical emissions released during processing pose occupational health risks, especially in informal or poorly regulated settings (Cook et al., Reference Cook, Derks and Velis2023). Moreover, mechanical recycling can result in the formation of complex and often poorly characterized chemical mixtures. These mixtures in recycled plastics may reintroduce hazardous chemicals into consumer products, including food packaging and children’s toys, raising safety concerns (Carmona et al., Reference Carmona, Rojo-Nieto, Rummel, Krauss, Syberg, Ramos, Brosche, Backhaus and Carney Almroth2023). Testing recyclates for a wide range of substances to ensure their safety is technically challenging, particularly for NIAS, and due to extensive time and analytical requirements, this can also be financially burdensome. In summary, hazardous plastic chemicals pose a broad range of safety and sustainability challenges and hinder a transition to plastics circularity, and if they are not regulated at the design phase, toxic leakage and emissions become increasingly challenging and costly to mitigate as supply chains become increasingly complex (Houssini et al., Reference Houssini, Li and Tan2025).

Way forward

Considering the above, we strongly recommend that the plastics treaty addresses chemicals of concern if it is to deliver on the goal of the UNEA resolution 5/14 to “protect human health and the environment.” Addressing chemicals of concern is also a prerequisite to achieve the treaty objective to make plastics safer, more sustainable and more circular. There are three major pathways to improve the chemical safety of plastics.

First, the use of known chemicals of concern in plastics will be best regulated based on their hazards (Wagner et al., Reference Wagner, Monclús, Arp, Groh, Muncke, Wang, Wolf and Zimmermann2024). Phase-outs of known chemicals of concern globally have been implemented in the past, and continuing this process will have substantial benefits for public and environmental health and result in significant cost savings (Cropper et al., 2025). It will also provide regulatory clarity and a level playing field for plastic manufacturers (Scientists’ Coalition for an Effective Plastics Treaty, 2024). Importantly, these benefits and the success of the instrument will be significantly greater if phase-outs are global and comprehensive rather than national and limited in scope.

Second, the widespread lack of transparency, traceability and trackability on plastic chemicals hinders not only the implementation of effective policies, such as trade restrictions, but also a just transition toward safer and more sustainable plastics. Hence, the treaty should consider plastic chemicals data as public interest information and require plastic producers to publicly disclose the chemical composition of plastics. This is an area that has not seen much progress so far and would support the universal human right to access to information, enabling consumers to make informed decisions and supply-side actors to proactively improve the safety and sustainability of their products, meaning that sustainable chemistry would be used in the design of products and processes, with the aim to minimize waste and the generation of hazardous substances.

Third, redesigning plastic materials and products to improve their safety and to facilitate chemical simplification will be key to avoid shifting to similarly harmful chemicals, enabling a transition to a truly safer and more sustainable plastics economy. An efficient mechanism to list new chemicals for global regulation can address this issue, but alone, it will be insufficient to end the “whack-a-mole” of new plastic chemicals (in which one hazardous chemical is merely replaced with another). Accordingly, incentivizing a safe-and-sustainable-by-design approach to new plastic materials and products that contain fewer and safer chemicals will require comprehensively assessing those chemicals, with premarket testing and postmarket regular monitoring and reporting requirements.