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Driving Change

Why ASI Chain of Custody

Learn how ASI's Chain of Custody approach is driving the uptake of responsible practices in aluminium supply chains

A Chain of Custody is a system that can be used to support traceability of materials and associated claims through a supply chain.

There are a range of different Chain of Custody (CoC) models that underpin these systems. They can be grouped into four main types: identity preservation, segregation (also known as bulk commodity), mass balance (whether at batch, site or group level) and book and claim (also known as certificate trading).


For aluminium, ASI’s Chain of Custody Standard takes a mass balance approach.

This allows mixing, under material accounting controls, and puts the focus on connecting the supply chain practices of the entities in the chain, not on atoms in the material.

The ASI Chain of Custody Overview brochure provides a brief description of the ASI Chain of Custody Standard, the mass balance system, claims and Responsible Sourcing logo, FAQ and more.


A requirement of ASI’s Chain of Custody Standard is to have the Performance Standard Certification as a foundation – through each step of the supply chain.

This because the existence of a chain of custody system alone does not specify the characteristics or the conditions under which materials or products are produced.

In this way, CoC becomes the link from company practices to their products. Under ASI’s comprehensive certification program, this link starts with bauxite or recycled aluminium, and can be continued right through each step of the supply chain to end users. In this way, responsible production is linked to responsible sourcing.


ASI members are responding to a growing expectation that the entire aluminium value chain becomes certified.

The most common drivers for uptake of ASI Chain of Custody Certification are to implement responsible sourcing and to meet customer or supplier demands.

We collect annual data on inputs and outputs of ASI bauxite, alumina and aluminium under our Chain of Custody program, and publish this each year in a global mass flow model. This visualises the uptake and flow of ASI CoC material over time.


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