How to evaluate a plastic credit project: a buyer's due diligence checklist

Why due diligence is non-negotiable

The plastic credit market does not have a single governing standard body, a mandatory public registry, or a centralised price benchmark. These structural characteristics place an unusually high burden of due diligence on buyers — a burden that many are not currently meeting. A study by Changing Markets Foundation in 2024 found that 41 percent of surveyed corporate plastic neutrality programmes could not provide verifiable evidence linking their stated plastic offset volumes to specific, audited projects. In a market that is increasingly subject to regulatory scrutiny under the EU Green Claims Directive and national greenwashing enforcement, inadequate due diligence is not a technical shortcoming — it is a legal and reputational liability.

This checklist covers the seven questions that any procurement team must be able to answer before committing capital to a plastic credit purchase. It identifies the specific documents to request at each stage, and the red flags that should pause or halt a purchase decision.

Step 1: Which standard governs the credit?

The governing standard determines the verification rigour, additionality requirements, and registry transparency that underpin the credit. The hierarchy of institutional rigour, from highest to lowest, runs: Verra PWRS (full public registry, accredited VVB, multi-stage review), Gold Standard (SDG-focused, public registry, independent VVB), Prevented Ocean Plastic by Bureau Veritas (ISO-aligned, third-party certified, ocean-bound specific), rePurpose Global (intermediary-managed, third-party audited, no direct registry access), CleanHub (proprietary, digital monitoring, lighter verification model), and uncertified proprietary standards (no independent audit, no public registry).

Documents to request: The project's registration certificate on the governing standard's registry. The name of the accredited methodology applied (e.g. VMR0006 for Verra mechanical recycling credits, VM0046 for chemical recycling).

Red flag: A seller who cannot name the governing standard and the accredited methodology, or who describes the project as 'verified' without identifying the verifying body, is disclosing an unverified credit.

Step 2: Is additionality demonstrated?

Additionality is the requirement that the plastic collection or recycling activity would not have occurred without credit revenue. A non-additional credit funds activities that would have happened anyway, providing no environmental benefit beyond what baseline conditions already deliver.

Additionality is assessed through a project-level counterfactual analysis: what would have happened to the plastic waste in the project area if the project did not exist? For ocean-bound projects in countries with mismanaged waste rates above 70 percent, additionality is generally credible — the counterfactual is open dumping, burning, or waterway leakage. For projects in middle-income countries with existing formal collection infrastructure, additionality requires more detailed justification and is more frequently contested at VVB audit.

Documents to request: The additionality section of the Project Description (PD) submitted to the governing standard body. For Verra PWRS, this is a publicly available document on the Verra project database.

Red flag: A project that cannot articulate what would happen to plastic waste in its catchment area without the project, or that relies on vague 'waste management gaps' language without country-level evidence, has not demonstrated additionality adequately.

Step 3: What monitoring infrastructure is in place?

The quality of monitoring data determines the ceiling on credit quality. Weight records from collection operations are the primary evidentiary chain from which all downstream calculations flow. Projects relying solely on aggregated monthly weight estimates without point-of-collection records carry materially higher verification risk.

Best-practice monitoring systems include: certified digital scales at each collection hub, GPS-tracked collection vehicles with route logging, mobile application-based weight ticketing from individual waste pickers, and an integrated weight management system (WMS) that aggregates collection data in near real-time. A World Resources Institute analysis of 47 active projects found that informal-sector monitoring gaps generate weight estimation errors of 15 to 25 percent — meaning credited volumes may not correspond to plastic actually diverted.

Documents to request: A description of the monitoring system architecture, including the equipment used, calibration records for weighing equipment, and whether monitoring data is digitally generated or manually recorded.

Red flag: Monitoring that relies entirely on paper records, manual aggregation, or self-reported monthly totals without independent cross-referencing is a significant data integrity risk.

Step 4: Who is the VVB and when did they last audit?

The Validation/Verification Body (VVB) is the independent third-party auditor whose opinion transforms self-reported data into a market-credible credit. For Verra PWRS, VVBs must be independently accredited by Verra from a list that includes TÜV Rheinland, Bureau Veritas, SCS Global Services, and Rainforest Alliance — each with established audit track records and structural independence from project developers.

Documents to request: The verification statement — the VVB's formal attestation of the verified plastic volume, the integrity of the monitoring process, and any findings raised during audit. Request the VVB's contact name and ask whether you can make a reference call to confirm the engagement. Legitimate VVBs will support this request.

Red flags: A credit with no named VVB. A VVB that is a subsidiary or affiliate of the project developer. A verification conducted exclusively through document review with no site visit — site visits are standard for credible verification and their absence is a significant weakness.

Step 5: Is there a public registry record?

Legitimate credits issued under institutional standards are recorded in a public or independently auditable registry with unique serialised entries. The Verra registry (registry.verra.org) is fully public; any market participant can search by project, vintage, and credit serial number to verify issuance and retirement status. Gold Standard's Impact Registry provides equivalent functionality. Plastic Bank's proprietary registry is blockchain-backed and independently auditable on request.

Documents to request: The credit serial numbers for the specific credits you are purchasing. Cross-reference these against the public registry before executing the purchase to confirm they exist, have not been previously retired, and match the project description provided.

Red flag: Credits that exist only in a PDF certificate or email attachment, with no traceable registry entry. This is the most common form of plastic credit fraud and the easiest to prevent through basic due diligence.

Step 6: Are co-benefits verified?

If a credit provider is making social co-benefit claims — waste picker income uplift, gender impact, health improvements — these must be supported by independently verified data, not project developer narrative. The IRIS+ framework, published by the Global Impact Investing Network, provides standardised metrics for income, employment, and environmental impact that enable comparison across projects.

Documents to request: IRIS+ metric reporting for the relevant crediting period. A copy of the most recent social audit report — ideally from an SA8000-accredited auditor. Gender-disaggregated income data from periodic household surveys, conducted by an independent third party rather than the project developer.

Red flag: Co-benefit claims supported only by project developer testimonials, case studies, or non-IRIS+ metrics without an independent audit trail.

Step 7: What is the forward supply security?

For multi-year plastic neutrality commitments, ensure the project has a credible supply pipeline. Key questions: Is the project operating within a renewable crediting period (Verra credits periods are up to 10 years)? Has the project demonstrated stable or growing collection volumes across multiple verified crediting periods? Is the project dependent on a single collection community or geography, creating concentration risk?

Documents to request: Historical verified credit volumes across all completed crediting periods. A letter of intent or offtake agreement specifying the price, volume, and term of forward credit supply.

Red flag: A project selling only its first-ever crediting period, with no verified track record, at a price that implies high quality — without a credible explanation for the combination.