What double counting means for plastic credits
A plastic credit represents one unit of plastic waste that was collected, recycled or diverted from the environment. Double counting happens when that same unit is sold, claimed or retired more than once. If it happens, the buyer pays for an outcome that was already paid for or claimed by someone else, and the credit no longer represents a real change in waste flows.
Double counting is the central integrity question for the market. Buyers ask it when they compare credit types, and reporters ask it when they decide how to disclose a plastic claim. This explainer sets out where the risk comes from and what protects against it.
Where the risk comes from
Double counting can enter the market through three routes:
- The same tonnage is sold twice. A project developer sells credits for a collection volume in a bilateral contract and also lists the same volume on a registry, or sells it to two buyers.
- The same waste is claimed in two schemes. A producer uses plastic collected in a region to meet an extended producer responsibility (EPR) obligation and then offsets the same tonnage with a voluntary credit.
- A retired credit is claimed again. A credit is retired for one buyer and later resold or cited by another company as if it still existed.
The first route is the most common in unregistered markets. The second is the hardest to see from the buyer's side, because the EPR system and the voluntary market keep separate records.
How registries reduce the risk
Registry-based standards address the first and third routes directly. Verra's program FAQ says that each plastic credit carries a serial number, that the serial indicates the material type collected where that is known, and that it includes a geographic market identifier. Because each serial is unique on the registry, a credit can be traced from issuance to retirement.
Retirement is the step that removes the credit from circulation. Verra's FAQ says companies can retire plastic credits verified to the rules of its Plastic Standard to show their contribution to reducing plastic waste. A retired credit cannot be sold or transferred again, which is why the retirement record matters more than the original issuance for a buyer.
Verra's quality assurance principles state that key safeguards are put in place to prevent double counting of collected and recycled plastic waste. These safeguards operate within the registry. They do not automatically cover what happens outside it.
Where registries cannot help on their own
A registry only sees what is recorded on it. Three gaps remain:
- Off-registry sales. A developer may sell volume that was never issued as a credit, or sell a forward contract on tonnage that is later issued to someone else.
- Parallel schemes. Plastic collected to meet an EPR target may also be offered as a voluntary credit, unless the developer and the producer agree how the volume is allocated.
- Claims on the buyer's side. A company that retires a credit must still describe it accurately in its reporting. Retiring a credit does not allow a company to claim recycled content it did not actually use.
For this reason, the strongest protection is a combination of registry evidence and a written statement from the seller.
What a buyer should check before purchase
Before buying, work through a short checklist:
- Serial numbers. Look up each serial number on the registry and confirm it matches the quantity, material type and location in the quote.
- Retirement record. Confirm the credits are retired in your company's name, and that the retirement is final and not pending.
- No other claims. Ask the seller to confirm in writing that the tonnage has not been sold, retired or used for EPR compliance elsewhere.
- Vintage and period. Check that the collection period matches the reporting period you intend to cover, so the same tonnage is not used across two years.
- Disclosure wording. Describe the purchase as a credit retired against a stated plastic waste outcome, not as a reduction in your own plastic use.
Frequently asked questions
Is double counting the same as fraud?
Not always. Some double counting is an accident, for example when two sellers list the same project without knowing. Intentional double selling is fraud. In both cases the buyer carries the reputational risk, so the checks above are worth doing regardless of intent.
Does a registry serial number guarantee that a credit is unique?
It shows that the credit is recorded once on that registry. It does not show that the tonnage was not used in another scheme, so the seller's written statement still matters.
What should I do if a retired credit appears in another company's report?
Check the registry retirement record first. If the record shows your company as the beneficiary, ask the other company for its evidence. If the record does not match, raise it with the registry and with the seller, and keep a written record of the exchange.
About the author
Plastic Units editorial team
Editorial team
The Plastic Units editorial team writes and maintains the Knowledge Bank and news on the plastic credits market, recycling economics and plastic policy.