CBAM ultimately rests on regulatory values. Those values depend on relationships between goods, suppliers, producers, installations, reporting periods, emissions information and the documents that support them. WEETRA examines whether those relationships can be established from the evidentiary corpus under review.
The references below separate what the law requires from how WEETRA structures evidentiary review and from controls that WEETRA adds for robustness.
Version references, Evidence Manifests and SHA-256 integrity references are WEETRA controls. The Regulation does not prescribe those specific tools.
Official sourceRegulation (EU) 2023/956 · Art. 7(5)-(6) · Annex V · Art. 19(2)
Records supporting embedded-emissions calculations must be sufficiently detailed for verification and later review, and retained until the end of the fourth year after the relevant declaration year.
WEETRA tests whether the reviewed corpus preserves the source, fact and period relationships needed to reconstruct the evidentiary state later.
Version references, Evidence Manifests and SHA-256 integrity references are WEETRA controls. The Regulation does not prescribe those specific tools.
Official sourceRegulation (EU) 2023/956 · Art. 8 · Annex VI · Implementing Regulation (EU) 2025/2546 · Arts. 5-6 and Annex
Where actual emissions are used, the CBAM framework requires verification by an accredited verifier. Implementing Regulation 2025/2546 specifies materiality levels and minimum verification-report information.
WEETRA reviews and structures the documentary basis before regulated verification. The accredited verifier then performs its own procedures and reaches an independent conclusion.
WEETRA Review Levels define different depths of examination. They are not regulatory verification categories.
Official sourceImplementing Regulation (EU) 2025/2547 · Arts. 13-15
For complex goods, precursor reporting periods and source installations can affect the embedded-emissions calculation. Evidence may be required to establish the actual precursor period or installation subset.
WEETRA examines whether precursor values can be traced to the relevant producer, installation, period and evidentiary basis.
Official sourceRegulation (EU) 2023/956 · Art. 9(1)-(3)
A reduction based on carbon price paid requires records demonstrating the carbon price, relevant rebates or compensation, independent certification and evidence of actual payment, with retention through the fourth year.
WEETRA examines whether the file supports the carbon-price treatment being claimed and records documentary limitations where the evidentiary chain remains incomplete.
Primary legal texts prevail. Commission guidance is explanatory and is identified separately from binding law.
The evidentiary problem
The evidentiary problemHow the chain developsOne value, many dependenciesWhat WEETRA examinesWhat can breakFour documentary questions that often determine CBAM readinessFrom finding to remediationRelationship to verificationWhat the organisation receivesCBAM reporting produces figures. Embedded emissions attached to goods, quantities attached to declarations, carbon-price amounts attached to claimed treatment. Each figure is easy to place in a spreadsheet. What is harder is showing, months later, why that particular figure applies to those particular goods.
A number can be present in a file while the documentary relationship required to rely upon it remains unresolved. The value is not wrong in an arithmetic sense. It simply cannot be connected, from the material available, to the installation, the period or the source that would make it usable in a regulatory position.
This is the problem WEETRA works on. Within a defined evidentiary corpus and an agreed mandate, the review examines whether the relationships behind a declared value can be established, and records precisely where they cannot.
A CBAM position is not assembled in one moment. It accumulates across parties, systems and time, and each transition is a place where a documentary relationship can be established or lost.
Goods move during an import period. The importer or authorised CBAM declarant retains the regulatory declaration and the positions submitted under it. The information needed to characterise those goods, however, originates elsewhere. In the non-EU production chain, at the producing installation, in monitoring and emissions records maintained by parties the declarant does not control.
Where independent verification is required for the emissions information relied upon, an accredited verifier performs that regulated function. It is a separate, independent role, and it is not a check applied to every physical shipment.
The annual position then requires all of this to be correctly associated. The right emissions basis attached to the right installation, for the right period, for the right goods. Competent and customs authorities exercise the statutory powers assigned to them.
WEETRA sits alongside this chain, not inside it. The institute examines the documentary and evidentiary relationships supporting the positions being relied upon, within the agreed mandate. It does not participate in customs release and does not carry the declarant's responsibilities.
Reference sequence. The applicable path depends on the goods, the chain and the mandate.
An embedded-emissions figure is the end of a chain, not the whole of it. Between the imported goods and the regulatory position sit a series of relationships, each of which has to hold.
The existence of the final value does not itself establish everything upstream of it. A position may become difficult to sustain not because the number looks wrong, but because one necessary link cannot be demonstrated from the corpus reviewed.
Each step is a relationship that has to be evidenced, not assumed.
Depending on the mandate, the applicable Review Level and what the corpus actually contains, the examination may address relationships involving
Not every position applies to every file, and not every position is exercised in every engagement. Applicability follows the mandate, the regulatory scope and the evidence actually available.
The following are illustrative evidentiary questions, drawn from the kinds of situation a documentary review encounters. They are questions to be resolved, not automatic findings of failure.
Emissions data identify a producing installation, but the reviewed commercial and production evidence does not establish that the relevant imported goods came from it.
Commercial, production and emissions information refer to periods that cannot be cleanly reconciled with the period being claimed.
A precursor emissions value is relied upon, but the producer, installation, period or evidentiary basis behind that precursor is incomplete.
Customs, commercial and emissions records express quantities that do not reconcile with one another.
Two documents in the same file support materially different values for the same regulatory fact.
A verification report is present, but the reviewed corpus does not clearly establish its connection to the installation, period or emissions information relied upon.
A later correction exists, but the file cannot show which version supported a given past calculation or conclusion.
Evidence shows a nominal carbon-price amount, but the documentary basis does not necessarily establish every element required for the treatment claimed.
For the carbon-price evidence question, see Article 9 of the EU CBAM Regulation →
A payment receipt can establish that money moved. The review still has to connect the applicable carbon-pricing mechanism, liable entity, installation, covered emissions, relevant period, rebates or compensation, net amount and the CBAM claim relying on that payment.
An emissions value may identify an installation without proving that the imported goods were produced there. Commercial, production and shipment evidence has to carry that relationship.
For complex goods, a precursor value may depend on another producer, installation or reporting period. The file needs to show which precursor data were actually used and what supports them.
Customs quantities, invoices, production records and emissions workbooks can all be individually plausible while referring to different masses, units or periods. Cross-source reconciliation shows whether they describe the same underlying flow.
Concrete cases make the evidentiary problem easier to see. These examples do not replace the full review; they show why a figure or document can exist while the relationship needed to rely on it is still unresolved.
Stating that a document is missing is not a review. It is the beginning of one.
Where the mandate provides for it, the review seeks to identify not only what is unresolved but what depends on it and what would settle it. Which claim rests on the unresolved point, which evidence was actually examined, why that evidence does not currently carry the claim, and which party is likely to hold the clarifying information.
That turns a generic supplier questionnaire into a targeted request. It also makes the outcome checkable. When new or corrected evidence arrives, it is reviewed against the same claim, and the file records whether the point became established, remained source-limited, or continued to block the position under the applicable review approach.
Remediation is not a guarantee. Some points resolve, some remain bounded by the sources available, and the reviewed state records which is which.
Remediation applies where the mandate includes it.
Organised in advance, a reviewed file changes the character of that external exchange. Evidence is ordered, installation and period relationships are set out, open findings are identified rather than discovered late, remediation history is documented, versions are controlled, and the basis relied upon can be reconstructed.
Where accredited verification is required, the WEETRA review record can accompany the underlying file while the accredited verifier performs its own procedures and issues its own report.
According to the Review Level and the mandate, outputs may include
The purpose is not only to state a conclusion. It is to preserve enough of the reviewed basis for that conclusion to be reconstructed later, by someone who was not present when it was reached.
The review record is designed to remain useful beyond the engagement. It can support internal decision-making and subsequent professional review by advisers, customs teams or other reviewers. Where accredited verification is required, the underlying file and WEETRA review record can be made available while the verifier performs its own independent procedures.
WEETRA can discuss the scope, the appropriate Review Level and the evidentiary questions specific to a CBAM file.
