6PPD in tyres
why it’s used
and EU regulatory actions
Key Takeaways
6PPD (CAS: 793-24-8) helps protect tyre rubber from ageing and cracking caused by ozone and oxidation, supporting the durability and integrity of the tyre.
EU authorities are gathering evidence as part of ongoing regulatory work, including a potential REACH restriction process covering a group of substances that includes 6PPD.
Tyres Europe is contributing technical input and supports an evidence-based approach before any regulatory decision is made.
The tyre industry has sponsored research to further scientific understanding of 6PPD’s
presence in the environment and is working on finding potential alternatives.
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6PPD overview
Safety is at the core of everything tyre manufacturers do.
6PPD is used in tyres and other rubber products to help prevent cracking caused by ozone and UV exposure, extending product life and supporting the integrity and safety performance of the tyre.
6PPD is covered by chemical regulations worldwide, including the EU Regulation on Registration, Evaluation, Authorization and Restriction of Chemicals (REACH).
Without 6PPD, a tyre’s integrity would be severely and quickly compromised, jeopardising driver and passenger safety. While there is currently no alternative ready to be implemented short-term, alternatives are being developed, tested, and systematically assessed.
EU regulatory actions on 6PPD: what is the EU REACH restriction process?
In the EU, potential human health and environmental risks are assessed under the REACH Regulation through regulatory structured processes (restrictions or authorisations) that include risk and socio-economic assessment and stakeholder consultation(s).
REACH restrictions can limit or ban the manufacture, placing on the market or use of a substance on its own, in mixtures, or in articles.
In 2025, the Austrian and Dutch competent authorities formally confirmed their intention to prepare a REACH restriction dossier covering 6PPD and chemically related substances.
As part of this preparatory phase of the restriction dossier, ECHA launched a call for evidence in December 2025, which ran until March 6, to gather information on:
- the function of PPDs in tyres,
- (eco)toxicological data,
- environmental fate and exposure,
- potential alternatives,
- and socio-economic impacts.
This step is designed to inform the preparation of an Annex XV restriction dossier, not to pre-judge its outcome.
Once the restriction dossier is submitted, the subsequent REACH process would include a risk assessment of 6PPD and socio-economic analysis of the impacts of a 6PPD restriction. The process would typically take 2 to 3 years to complete.
Any future regulatory measure would therefore depend on the outcome of this evidence-based process and on the availability of safe, effective and scalable alternatives that do not compromise road safety.
What is the EU REACH restriction process?
In the European Union (EU), potential human health and environment risks are assessed under REACH, through a structured process that includes scientific assessment and stakeholder consultation(s). Restriction dossiers are evaluated by the European Chemical Agency’s (ECHA) scientific committees RAC and SEAC and then the European Commission proposing a restriction which can be supported by EU Member States in the REACH Committee.
Restrictions can limit or ban the manufacture, placing on the market or use of a substance (on its own, in mixtures, or in articles).
Key actors and steps
- An EU Member State, or ECHA (on request of the Commission), can propose a restriction.
- The proposal is subject to public consultation (stakeholders can submit evidence and comments).
- ECHA’s committees for risk assessment (RAC) and socio-economic analysis (SEAC) deliver opinions, considering consultation input.
- The European Commission, together with Member States, takes the final decision and amend Annex XVII of REACH.
What happens next
After the Call for Evidence closes, the dossier submitters typically prepare the restriction dossier (Annex XV). If a dossier is submitted and accepted as conforming, the process usually includes a public consultation of six months and committee opinion development, before the Commission moves toward a restriction proposal.
EU REACH restriction process for PPDs (including 6PPD)
Indicative timeline. Exact dates may shift depending on dossier submission and the development of an opinion by the ECHA Scientific Committees.
Where are we now: Tyres Europe’s contribution to the 6PPD Call for Evidence
Tyres Europe has submitted feedback to the Call for Evidence (CfE) launched by Austria and the Netherlands in view of their intention to submit an Annex XV restriction dossier. The dossier concerns a group of phenyl-p-phenylenediamines (PPDs) and para-substituted phenylenediamines (PDs) used as antioxidants/antiozonants in rubber tyres. 6PPD is one of the substances to be covered in the restriction dossier.
This contribution reflects the European tyre industry’s continued engagement in the regulatory process and its commitment to evidence-based decision-making.
Tyres Europe will continue contributing data and technical expertise as the work progresses, including on:
- the function of these substances in tyres,
- the technical complexity of substitution in safety-critical applications,
- and the conditions needed for any alternatives to be safe, effective and scalable.
To date, there is no universally validated alternative to 6PPD that is already proven to, for example, prevent premature tyre aging while meeting stringent safety requirements across tyre applications at industrial scale.
At the same time, tyre manufacturers are actively investing in research on potential alternatives, including through a consortium of more than 30 global tyre manufacturers led by the U.S. Tire Manufacturers Association (USTMA). When considering alternatives, it is important to avoid regrettable substitutions; that is, switching one substance for another and potentially shifting the risks to another type of hazard.
Under the umbrella of the World Business Council for Sustainable Development’s Tire Industry Project (TIP), the tyre industry has also sponsored research to further scientific understanding of the transformation processes of 6PPD in different compartments, such as soil and water. For broader work on tyre and road wear particles, see here.
The European tyre industry remains committed to complying with the REACH Regulation and all relevant EU chemical legislation, while continuing to collaborate constructively with authorities as the regulatory process progresses.
Frequently Asked Questions
Is 6PPD used in all types of tyres (PLT, TBR, bicycle)?
Because of its antiozonant and antioxidant properties, 6PPD is used in most types of tyres (~97%).
Are there alternatives to 6PPD?
Currently, there is no fully validated, universally applicable alternative to 6PPD that is already REACH-registered, approved, available at scale, and demonstrated to deliver equivalent tyre safety, durability, and performance across all tyre types and uses.
6PPD plays a critical role in tyre safety by protecting rubber against ozone and oxidative degradation. Tyres are highly complex systems in which multiple materials must work together to meet stringent safety and performance requirements. As a result, replacing a single substance cannot be done on a one-to-one basis without extensive reformulation, testing and validation, to ensure that tyre safety and service life are not compromised.
That said, significant progress is underway. Several potential alternatives to 6PPD are under active development by chemical suppliers, and scientific understanding has advanced. However, these candidates are at different stages of development and still face challenges related to:
- toxicological and environmental assessments,
- regulatory approval including development and validation of REACH registration dossiers for
substances produced/placed on the market above 1000 tonnes per year in Europe - long-term performance and durability of different type of tyres including many applications,
- and industrial-scale production capacity.
In the U.S., a consortium of more than 30 global tyre manufacturers led by the U.S. Tire Manufacturers Association (USTMA) is conducting a comprehensive alternatives analysis under the state of California’s rigorous and transparent Safer Consumer Products Regulations (SCPR) to identify an alternative to 6PPD in tyres.
Any potential alternative to 6PPD identified through the SCPR process must provide at least equivalent tyre safety and performance to 6PPD, while improving environmental metrics.
Further reference to alternative analysis process in the US – Q&A.
Why is finding an alternative to 6PPD complex?
Tyres are manufactured using a precise combination of rubber compounds and advanced materials to meet critical performance requirements, including safety, durability, fuel efficiency, and environmental sustainability. Substitution of ingredients requires close attention to the tyre performance and hence, involves adequate testing. This is especially true for antioxidants and antiozonants, whose potential substitution is a long and complex process. Therefore, comprehensive evaluation of alternatives is needed.
The integrity, safety, performance and sustainability of our products remain our uncompromising priority.
Any alternative identified must continue to ensure compliance with the EU chemical regulations, including REACH and other consumer, vehicle and tyre manufacturer requirements.
Before any actual alternative can be implemented, extensive testing will be required to ensure tyre safety and performance, including for retreaded tyres.
As mandated by REACH, all chemical substances, including 6PPD, must be safe for human health and the environment. The European tyre industry is committed to complying with chemical legislation at all stages of tyre manufacturing.
What are the challenges of substituting 6PPD in tyres?
The European Commission has identified five primary challenges with the current REACH substitution regulatory framework and/or its implementation that is hindering the replacement of hazardous substances with safer, more sustainable and feasible alternatives.
1. Substitution requires time and resources and challenges vary between uses and users of hazardous substances.
2 & 3. Both value chain characteristics and uniform transition periods can hinder substitution.
4. Risks of regrettable substitution arise.
5. Obligations for involvement in the substitution process amongst all actors are lacking.
Tyres Europe agrees with the five primary challenges as identified by the Commission. However, we emphasise that certainty regarding upcoming and future chemical regulations is a crucial element that needs to be taken into account to ensure a predictable business environment.
Further challenges to replacing hazardous substances with less hazardous alternatives include compatibility issues and reduced performance.
Alternative chemicals may not be compatible with existing equipment and processes, necessitating significant investments in new technologies or modifications to current systems within production facilities, which takes time to implement.
The performance of the alternatives must match or exceed that of the original chemical in specific applications. An alternative chemical might not have equivalent properties in a mixture or compound, or between different mixtures, resulting in lower-quality properties and performance of
the final article. An alternative chemical needs to be assessed on the basis of its suitability for a specific application, rather than solely on a hazard-based approach.Moreover, one needs to consider that substitution planning involves the global supply chain, which needs to adhere to new developments, and regional solutions are not suitable for the industry.
How do manufacturers evaluate the chemicals that they use to make their tyres before a product is released?
The tyre industry’s #1 focus is making safe tyres, along with attention to the choice of substances regarding their impact on health and the environment; every ingredient used in a tyre serves a unique purpose in the tyre’s design and performance.
For any substance manufactured or placed on the EU market above 1000 tonnes per year, a fully completed REACH dossier should be registered to demonstrate that a substance can be safely manufactured and used in the EU. This dossier includes toxicological and ecotoxicological information, as well as hazard assessment, among other things.
6PPD is not an exception, and a dedicated registration dossier, duly filled in by chemical producers, considers and assesses all uses, including the environmental effects that the use of the substance may pose.
What can be done about 6PPD/6PPDQ in the environment while tyre manufacturers develop alternative(s) to 6PPD?
Examples of mitigation measures include street sweeping in urban areas, choosing pavement surfaces (such as rubber-modified asphalt and permeable pavement) that reduce tyre abrasion and mitigate stormwater impacts, installing bioretention technologies to treat stormwater and maintaining proper tyre inflation to reduce tyre abrasion. For broader work on tyre and road wear particles, see here.