CBAM Verification and Accredited Verifiers: Accreditation, Site Visits and Preparation

Why verification became mandatory

Transitional-period emissions data was not verified. Under the definitive regime the same data forms the tax base of a financial obligation, so independent assurance became mandatory. The logic mirrors the principle that a tax base is independently audited.

The verifier applies a risk-based approach and must form an opinion providing reasonable assurance that total emissions are not materially misstated and that the report can be verified as satisfactory. This is assurance against material error rather than absolute accuracy — but what counts as material is determined by the verifier's risk assessment, and that assessment reflects the quality of the installation's data. Where data infrastructure is weak, risk is assessed as high, sampling expands and the process takes longer.

Verifier accreditation

CBAM verification cannot be performed by any independent body. The verifier must be accredited under CBAM by an EU national accreditation body. Delegated Regulation (EU) 2025/2551, published in November 2025, sets the conditions for granting accreditation, the control and oversight of accredited verifiers, withdrawal of accreditation, and mutual recognition and peer evaluation between accreditation bodies.

Two features ease the position of verifiers established outside the EU. An application to a single EU accreditation body is sufficient; separate accreditation in each member state is not required. And existing verification capability under the EU ETS, ISO 17029 and ISO 14065 is taken into account in the accreditation assessment.

Accreditation bodies that have indicated they accept third-country applications include Accredia (Italy), RvA (the Netherlands), SWEDAC (Sweden) and PCA (Poland). The first CBAM accreditations were expected around September 2026; verifier registration in the CBAM Registry opened on 1 September 2026, and the first verification reports are expected in January 2027.

National accreditation outside the EU

A frequent source of confusion is the assumption that a verifier holding national accreditation in the country of production can perform CBAM verification. Current rules require accreditation from an EU national accreditation body.

The recognition of third-country accreditation is an active policy question. The Commission's revision proposals include the possibility of agreements on mutual recognition of third-country accreditation bodies, and exporting countries — Türkiye's Ministry of Trade among them — have raised recognition of their national accreditation body as a priority. Until such an agreement exists, the practical requirement when selecting a verifier is to confirm which accreditation it holds. Holding ISO 14064 verification accreditation does not imply CBAM competence.

The site visit rule

Verification is not a desk exercise. A physical site visit is mandatory in the first year. Flexibilities apply subsequently — virtual visits or exemptions in defined circumstances — with an expectation of a physical visit at least every two years. For electricity emissions, a single site visit covering five reporting periods is accepted.

Site visit scheduling is the most frequently underestimated item in the calendar. Verification of 2026 data will concentrate in the first half of 2027, and the number of accredited verifiers will be limited. Contracting early is how a visit date gets into the calendar at all.

What the verifier examines

• The monitoring methodology document. Source list, measurement methods, emission factors and their justification, data collection frequency, responsibilities.
• System boundary decisions. Justification for what was included and, equally, what was excluded.
• Attribution decisions. The method and consistency of heat, electricity and waste gas allocation.
• Data traceability. Every declared figure traced back to a source document: invoices, weighing records, laboratory analyses, production reports.
• Precursor data. The nature and provenance of emissions data received from suppliers.
• Internal controls. How data entry errors are caught and reconciled.

Where a carbon price paid in the country of production is to be deducted, the emissions report verifier must also verify that amount — so the verification scope is not limited to emissions. We cover the deduction in carbon price paid in a third country.

A practical preparation sequence

1. Draft and internally approve the monitoring methodology document.
2. Establish the data collection regime and run it for at least one quarter.
3. Reconcile internally: compare the figures to be declared against source records.
4. Select a verifier and confirm the scope of its accreditation.
5. Fix the site visit date and brief the functions involved.
6. Close findings and record the verification report in the CBAM Registry.

Step four is often left late and proves expensive. Obtaining the verifier's view on methodological choices at the start of the period, rather than at the end, removes the risk that a year's data turns out to be unusable. The calculation build is covered in calculating CBAM embedded emissions.

Frequently asked questions

Is verification repeated every year?

Yes, each reporting period requires its own verification. Site visit frequency is where the flexibility sits.

Can our existing ISO 14064 verifier do this?

Only if it holds CBAM accreditation from an EU accreditation body. Existing ISO capability supports an accreditation application but does not substitute for it.

Is verification needed if default values are used?

No. Default values are not subject to verification, which removes the verification cost at the price of the mark-up.

What happens if the verification opinion is adverse?

Actual values cannot be used, and the goods revert to default values with the mark-up applied.

Sources

• European Commission — CBAM verification
• European Accreditation — the EU CBAM and the role of accreditation

We work on preparing the monitoring methodology, establishing data traceability and readying installations for verification, under our CBAM accounting and reporting service. You can contact us with your questions.