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Definition

Chain of custody for sustainability claims

A sustainability chain of custody sets the rules for carrying a defined material characteristic through purchases, processing and sales, including what may be mixed, how quantities are converted and which claim the records support.

What is a chain of custody for sustainability claims?

A chain-of-custody system tracks a defined characteristic, such as certified or recycled content, within programme boundaries. Its rules decide which inputs qualify, how the characteristic moves to outputs and what you may claim.

Why does chain of custody matter to you?

Customers and auditors may test your claim against purchase, processing and sales records. Regulation (EU) 2017/821 requires covered Union importers to document traceability: Article 4(f) lists mineral suppliers, origins, quantities and dates; Article 4(g) lists metal suppliers and smelters or refiners.

How does chain of custody work?

ISEAL's six models cover separate material, controlled mixes, quantity ledgers and certificate transfers. Before assigning a characteristic, record the covered products, where transfers are allowed, the unit, conversion factor, time limit, how outputs receive it and approved claim wording.

Apply the programme's conversion factor before comparing eligible inputs with claimed outputs. Some mass-balance programmes permit a temporary deficit if receipts and claims balance within a defined reconciliation period. Others require enough eligible quantity before each claimed sale.

What mistakes should you avoid?

  • Combining products, sites or periods that the programme treats separately.
  • Carrying input kilograms into an output ledger without the required conversion factor.
  • Assuming every temporary deficit is either allowed or forbidden.
  • Presenting an accounting claim as proof of physical content.

How is chain of custody different from supply-chain traceability?

Supply-chain traceability follows a material, product, supplier, site or claim through documented value-chain events. Chain of custody adds the programme rules that control how a specified characteristic is transferred, transformed and claimed.

What records should you provide for a custody claim?

Provide the programme rules, certificate scope, supplier and batch records, receipts, processing yields, dispatches, conversion calculation, period balances and the exact statement used. Each quantity should carry a date, unit and product group.

Example

Suppose a chemicals distributor in France follows a hypothetical mass-balance programme for acetone carrying a bio-based characteristic at one warehouse. Under that programme, a supplier certificate makes a receipt eligible for the acetone ledger. The rules use one product group, a July-to-September reconciliation period and a hypothetical conversion factor of 0.92 kg claimable output per kg eligible input to account for loss; they permit a temporary deficit within the quarter.

The distributor makes an 8,000 kg claimed sale in July, taking its ledger from 0 kg to -8,000 kg. In September it receives 10,000 kg of eligible input. That creates 10,000 kg x 0.92 = 9,200 kg of claimable output, so the quarter closes at 0 + 9,200 - 8,000 = 1,200 kg and meets the hypothetical rule. If only 8,000 kg had arrived, the converted quantity would be 7,360 kg and the quarter would close at -640 kg, which would fail reconciliation.

Where it comes up

EU Conflict Minerals Regulation mineral chain-of-custody recordsRegulation (EU) 2017/821, Articles 2(e) and 4(f)Official sourceEU Conflict Minerals Regulation metal chain-of-custody recordsRegulation (EU) 2017/821, Article 4(g)Official source

Related terms

Book-and-claim

Book-and-claim is a chain-of-custody model that transfers a verified sustainability characteristic separately from the physical product, then retires the certificate so that characteristic can be claimed only once.

Product carbon footprint (PCF)

A product carbon footprint (PCF) is the greenhouse gas emissions assigned to one product across a stated life-cycle boundary and expressed per declared or functional unit.

Primary vs secondary GHG data

Primary GHG data records a specific site, product, activity, or supplier, while secondary GHG data estimates that activity with external averages, databases, financial factors, or other proxies.

Sustainability contract clause

A sustainability contract clause makes environmental or social duties binding in a commercial agreement by defining the required data, targets, records, reporting dates, cooperation and remedies.

Sources

  • International Organization for Standardization

    ISO 22095:2020 cross-sector chain-of-custody framework, model requirements and the limit on what the system alone proves

    2026-08-20

  • ISEAL Alliance

    Six model headings, system boundaries, product groups, conversion factors, reconciliation periods and programme-dependent temporary deficits

    2026-08-20

  • European Union

    Regulation (EU) 2017/821 Articles 2(e) and 4(f)-(g) chain-of-custody and supply-chain-traceability records for covered Union importers

    2026-08-20

Last verified 2026-08-20

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Chain of custody for sustainability claims Definition | Keslio