CBAM enters its charging phase in 2026, with free allowances phasing out on a set schedule to zero by 2034. The first six industries — steel, aluminium, cement, fertiliser, power and hydrogen — square their carbon books first because that cost flows straight into EU border duty.

Petrochemicals are not in the first wave, but the product carbon footprint pre-positioning clause is already written into the reporting framework. The practical reading: even if no payment is due now, batch-level emission data must be ready and verifiable, so when petchems are called, the ledger is not built from scratch.

The method hashes each batch's carbon figure with SHA-256 at the batch level, recomputable from the browser. Regulators and buyers get a verifiable hash rather than a PDF conclusion, so any single altered number is caught at once.

Cross-chain receipt recognition binds that certificate to the title, so the carbon ledger follows the cargo. Under a structure where an offshore SPV signs and the refinery clears its own quota, the carbon cost flows straight into the landed cost breakdown instead of being chased afterwards. Among the seven resale crude grades, Iraq's Basrah Light clears origin screening while Iranian origin is auto-rejected — the red line sits on the origin, not the buyer.