Sustainability claims are everywhere. From recycled plastics and responsibly sourced fibres to renewable fuels and low-carbon materials, a growing number of companies are committing that their products feature specific environmental or social attributes.
Yet verifying such claims is not always straightforward within complex global supply chains. Materials go through multiple processing stages, are blended, transformed, and traded across borders. Without robust systems to track and verify what happens along the way, the credibility of sustainability claims can quickly be called into question.
This is precisely where Chain of Custody (CoC) systems play a vital role.
The Framework Behind Sustainability Claims
Chain of custody provides the mechanisms that enable organizations to trace, account for, and communicate the attributes of materials as they flow through the supply chain. However, the application of such systems often varies across industries and sometimes lacks a common benchmark.
To address this challenge, ISO has released two international standards — ISO 22095-2 and ISO 22095-3 — to strengthen the global framework for chain of custody systems. They introduce internationally harmonized requirements for two widely adopted chain of custody models: the mass balance approach and the book-and-claim approach. Designed for cross-industry application, the new standards serve as a general reference to support certification bodies and policymakers, while facilitating cross-border trade.
Developed by ISO Technical Committee ISO/TC 308 (Chain of Custody), the new standards build on ISO 22095:2020, which establishes generic terminology and models for cross-industry use. While the original standard laid the conceptual foundation, the new editions go further by providing practical operational requirements for the two most prevalent chain of custody models.
Scope of the New Standards
ISO 22095-2 focuses on the mass balance model, widely used in chemicals, plastics, agriculture, textiles and other sectors. Under the mass balance system, materials with specific attributes — such as recycled or renewable content — may be mixed with conventional materials during processing.
Physical separation is not the priority; instead, accurate accounting of quantities entering and leaving the system is essential. The standard sets out detailed requirements for the operation of such models, including system boundaries, allocation rules, conversion factors and communication principles.
ISO 22095-3 addresses the other mainstream model: the book-and-claim approach. In this model, sustainability attributes are transferred through administrative instruments rather than physical material flows. Known as Transferable Instruments with Entitlement to Claim (TIECs), these instruments allow organizations to support sustainable production even when full physical traceability is not feasible.
The new standard establishes a globally aligned methodology for the creation, transfer and retirement of such instruments, helping avoid double-counting and improving transparency. It also provides a credible foundation for mechanisms such as Environmental Attribute Certificates (EACs) used in energy and environmental markets.
Jack Steijn, Chair of ISO/TC 308, stated:“The release of these two new standards further completes the chain of custody toolkit, delivering two important new instruments to the user community. They reduce the risk of misinterpretation and double-counting, strengthen the integrity of sustainability claims, and set core principles that will guide future standardization work across industries.”
