How to Verify Plastic-Free Claims With Lab Data

Written by: Scott Steveson, Specialist

Key Takeaways for Brands Using Lab Data

Laboratory reports cannot prove the complete absence of plastic. Detection limits, polymer panels, and lot variability create hard technical boundaries on what any dataset can substantiate.
Four evaluation lenses, covering evidence quality, claim scope, testing methodology, and practical relevance, determine whether laboratory data can support a defensible market claim.
A seven-step verification process, anchored to the California State Water Board microplastics framework, converts raw lab results into scope-locked, publicly checkable outcomes.
Independent third-party review closes the credibility gap between self-reported data and claims that withstand retailer scrutiny, regulatory attention, and litigation risk.
The Wellness Quality Institute offers Plastic-Free Pathway Verification that turns existing laboratory datasets into verified, registry-listed claims. Explore the Plastic-Free Pathway Verification program.

The Measurement Limits That Shape Every Claim

Detection can establish presence, not absence. A lab can find a plastic particle by isolating it and confirming chemically that it is a polymer. Proving that no plastic is present would require ruling out everything a method cannot see, including every particle below the detection floor, every polymer outside the tested panel, and every production lot that was not sampled. Those are fundamentally different tasks, and only the first is currently achievable.

Fragments of plastic suspended in blue water below the surface. — Plastic doesn’t disappear — it fragments. These secondary microplastics are the breakdown products of everyday objects, and independent research now detects them across the water supply. Detection, though, establishes presence, not absence.

The California State Water Board defines microplastics in drinking water as solid polymeric material with particles having at least three dimensions greater than 1 nanometer and less than 5,000 micrometers. That definition is broader than any validated analytical method can reliably reach. The two published California standard operating procedures illustrate the gap precisely. SWB-MP1-rev1, which uses infrared spectroscopy, applies to particles greater than 50 micrometers (µm). SWB-MP2-rev1, which uses Raman spectroscopy, applies to particles greater than 20 µm. The regulation contemplates particles down to 1 nanometer. The best validated methods start at 20 or 50 micrometers, which are thousands of times larger. The 1–20 µm fraction is not validated under either method, and everything below 1 µm, the nanoplastic range, is currently beyond reliable commercial measurement.

Colorful plastic fragments in water inside a laboratory petri dish. — Microplastics are particles smaller than five millimeters. Current methods can count and identify them at the upper end of that range, but reliable measurement falls away as particles get smaller — a limit that shapes every honest claim.

Three constraints bind every claim that flows from laboratory data:

Particle-size limits. No method detects every particle size. Raman spectroscopy, as used in SWB-MP2-rev1, applies above 20 µm. Infrared spectroscopy, as used in SWB-MP1-rev1, applies above 50 µm. A result of “none detected” means none were found above that instrument’s floor, not that none are present below it.
Polymer diversity. No single test screens every polymer type. A panel covering polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), polystyrene (PS), PVC, nylon (PA), polycarbonate (PC), and polymethyl methacrylate (PMMA) is comprehensive by current standards and still not exhaustive.
Lot-to-lot variability. A clean result on one production lot does not guarantee the next. Contamination routes, including packaging degradation, ambient air deposition, and filling equipment, vary across production runs.

A 2018 peer-reviewed study by Kosuth, Mason, and Wattenberg in PLOS ONE found anthropogenic particles in 81% of 159 tap water samples across five continents. A separate 2018 study led by Sherri Mason at the State University of New York at Fredonia, published in Frontiers in Chemistry, found microplastic contamination in 93% of 259 bottled water samples across eleven brands, with polypropylene, the material used in bottle caps, as the most common polymer identified. The World Health Organization’s 2019 assessment, Microplastics in Drinking-Water, found low concern on the limited evidence available while stressing that the evidence base is incomplete and more research is urgently needed. These findings are consistent with a single conclusion: plastics are effectively present in the environment, and no claim of total absence is one the science can currently carry.

Four Lenses for Evaluating Laboratory Evidence

Given these technical constraints on what laboratory data can prove, any defensible claim must be evaluated through multiple lenses that acknowledge these boundaries. Before any dataset can support a market claim, it should be evaluated across four dimensions. These are not regulatory requirements. They are a practical framework for understanding what a given report actually proves.

Evidence quality covers whether the laboratory ran appropriate contamination controls. These include blank samples processed alongside test samples to detect background contamination, spike recoveries that add a known quantity of material to confirm the method is detecting what it should, replicates that run the same sample multiple times to confirm consistency, and chain-of-custody documentation that records who handled the sample and when, from collection through analysis. A result without these controls is a number without a confidence level.

Scientists in white coats working with samples and microscopes in a laboratory. — Only a small number of laboratories can genuinely test for microplastics, and capability varies by instrument and method. WQI reviews a company’s existing third-party laboratory data against a defined standard — it does not run the tests itself.

Claim scope addresses what the data actually covers. A result from one SKU, one production lot, and one sampling date does not extend to a product line or a company. Defining claim scope precisely, including which product, which matrix, and which production period, separates a defensible statement from one that collapses under scrutiny.

Testing methodology determines whether the analytical method was appropriate for the product matrix. Raman spectroscopy, FTIR spectroscopy, and pyrolysis-GC/MS each have different detection floors, different strengths across matrices, and different failure modes. ISO 24187:2023 establishes general principles for microplastics analysis in the environment. ISO 16094-2:2025 addresses vibrational spectroscopy for microplastics in waters with low suspended solids. Method suitability for the specific product matrix must be demonstrated, not assumed.

Practical relevance asks whether the tested particle-size range and polymer panel are meaningful given the product and its likely contamination routes. A method that starts at 50 µm and covers four polymers produces a narrower finding than one starting at 20 µm covering eight polymers, and a claim built on the narrower dataset must acknowledge those boundaries explicitly rather than implying broader coverage.

A 7-Step Process to Verify Plastic-Related Claims

Define exact product scope and bill of materials. Identify the specific SKU or product and every material component, including packaging, closures, and liners, along with the production or sampling period the data will cover. Walking the package component by component and confirming that each element is within scope prevents the common error of applying a claim to a product when only part of it was tested. A claim limited to the product contents cannot extend to the packaging, and the reverse is also true.
Review laboratory qualification. The laboratory’s accreditation determines whether its results are reviewable. For example, California ELAP (Environmental Laboratory Accreditation Program) accreditation for the applicable microplastics method is one preferred qualification. ISO/IEC 17025:2017 accreditation is accepted where the microplastics method and the product matrix are explicitly within the accredited scope. Accreditation by name alone is insufficient. The specific method and matrix must be in scope.
Assess method suitability against validated ranges. Confirm that the analytical method is appropriate for the product matrix and that the tested particle-size range is clearly stated. Raman spectroscopy under SWB-MP2-rev1 applies above 20 µm. Infrared spectroscopy under SWB-MP1-rev1 applies above 50 µm. A method applied outside its validated range produces results that cannot be relied upon. Visual microscopy alone, which counts particles by eye, cannot chemically identify polymers and is not sufficient for substantiation without confirmatory spectroscopy.
Check data quality indicators. Review the dataset for procedural blanks, which are samples processed without the product to detect background contamination, and for reporting limits, which are the lowest concentrations the method can reliably quantify. Confirm spike recoveries, replicates, and chain-of-custody documentation. A result without adequate blank controls cannot be distinguished from laboratory contamination. Particle counts must be reported by size fraction, not as a single aggregate figure.
Confirm polymer panel coverage. Identify which polymers were screened. A minimum panel covering PE, PP, PET, PS, PVC, PA, PC, and PMMA represents current best practice. The dataset should also report unidentified particles with no spectral match, not just confirmed polymers, and include a category for other confirmed polymers outside the primary panel. A panel that screens only two or three polymers produces a narrower finding than the claim may imply.
Verify production or sampling period alignment. Confirm that the samples tested correspond to the production period the claim will cover. A result from a prior production run does not substantiate a claim about current product. Lot-to-lot variability means that a clean result on one batch is not a guarantee about the next.
Obtain independent third-party review. An independent reviewer with no commercial interest in the outcome assesses the full dataset, including laboratory qualification, method, matrix, particle-size range, polymer panel, reporting limits, blanks, spike recoveries, replicates, chain of custody, data recency, and product scope, against defined published criteria. This step converts a laboratory report into a reviewed finding with approved claim language attached. Without it, even rigorous data is perceived as self-reported marketing.

Decision Outcomes: Standard Met Versus Standard Not Met

An independent review produces one of two outcomes, and each has a specific meaning. Understanding these meanings helps brands use results correctly.

Standard Met requires two conditions together. The dataset must satisfy all applicable technical and data-quality requirements, and no reportable target polymer particles can be detected within the tested particle-size range at or above the approved reporting limits. A non-detect result alone is not sufficient. The reporting limits themselves must meet defined requirements, or the non-detect result is bounded by an inadequate floor and carries no substantive meaning. A Standard Met outcome does not establish the absence of plastic below the method floor, outside the tested particle-size range, outside the reviewed polymer panel, below the reporting limit, outside the registered product scope, or outside the registered production period.

Standard Not Met is issued where one or more requirements are unsatisfied. This may reflect:

Reportable target polymer particles detected within the tested range
Reporting limits that do not meet defined requirements
Incomplete data, inadequate blanks, or insufficient contamination controls
An analytical method inappropriate for the product matrix
Missing chain-of-custody documentation
Laboratory qualification deficiencies
Incomplete polymer analysis or incomplete product scope

A Standard Not Met outcome frequently reflects the testing rather than the product. It is a private outcome, with no public claim, no logo rights, and no registry listing, and the company may resubmit with corrected or additional information. Participating in a review creates no public downside risk.

Why Independent Review Matters for Your Brand

The gap between a laboratory report and a defensible market claim is not a paperwork gap. It is a credibility gap. When a brand publishes its own test results, the market reads it as marketing, regardless of how rigorous the underlying testing was. Self-reported data looks like grading your own homework, and buyers, retailers, and procurement teams discount it accordingly.

Independent review addresses this structurally. A third party with no commercial interest in the outcome, no role in the testing, and published review criteria assesses the dataset and issues findings. That separation is the source of credibility that self-reporting cannot produce.

The greenwashing risk is real and growing. Plastics litigation has expanded beyond traditional false advertising to include consumer protection, fraud, and environmental discharge theories. Claims such as “plastic-free” or “microplastic-free” are focal points when plaintiffs allege that statements cannot be substantiated. The FTC’s Green Guides, while not carrying the force of law, caution against broad, unqualified environmental benefit claims and remain the main federal reference point for environmental marketing. California’s DTSC added microplastics to its Candidate Chemicals List effective October 1, 2026, which signals continued regulatory attention to the category.

The Wellness Quality Institute’s Plastic-Free Pathway Verification converts existing lab data into scope-locked, publicly checkable outcomes. Every Standard Met product receives a public registry entry recording the verified party, product scope, matrix, production or sampling period, tested particle-size range, lower method limit, polymer panel, reporting limits, testing laboratory and its accreditation, verification and expiration dates, registry ID, approved result statement, and current status. Every public claim links to that registry ID, which makes the claim checkable rather than merely assertable. The verification period is 24 months from the sampling date of the most recent accepted dataset, and continued claim use after that date requires re-verification with current data.

A single assessment fee covers review, verification decision, and registry listing, with no separate mark-license or registry fee. Independent laboratory testing is arranged and billed separately by a qualified independent laboratory. Payment of the assessment fee does not guarantee a verification decision.

WQI Plastic-Free Pathway Verification does not certify that a product contains zero plastic, microplastics, or nanoplastics. It shows that the company is on a verified pathway toward plastic-free standards. Verification applies only to the reviewed products, submitted datasets, tested ranges, polymer panels, production or sampling periods, and supporting controls. WQI verification is not a California approval, government certification, or health or safety certification.

See how WQI’s verification process works.

Frequently Asked Questions

What does a laboratory result of “none detected” actually mean?

“None detected” means the method found no particles within its tested parameters, but those parameters have specific boundaries. The key point many brands miss is that reporting limits themselves must meet defined requirements, or a non-detect result is bounded by an inadequate floor and carries no substantive meaning.

Who performs the testing that WQI reviews?

A qualified independent laboratory, not the Wellness Quality Institute, performs the testing. The Wellness Quality Institute does not run laboratory tests. The preferred laboratory qualification is, for example, California ELAP accreditation for the applicable microplastics method. ISO/IEC 17025-accredited laboratories are accepted where the microplastics method and the product matrix are explicitly within the accredited scope. Other qualified independent laboratories may be conditionally accepted through a documented method-equivalence review. WQI’s separation from the testing it reviews is what makes its review independent, and that independence is the source of the credibility a self-reported result cannot have.

Does verification apply to an entire product line?

Verification applies only to the specific reviewed product, model or SKU, product matrix, production or sampling period, tested particle-size range, polymer panel, and analytical method. No company-wide or product-line claim may be extended from a single dataset. A brand with multiple SKUs seeking to make claims across a line would need each product reviewed against its own dataset. This scope lock is not a limitation. It is what makes the claim defensible, because a claim narrow enough to be true is one that holds up when a retailer, journalist, or litigant examines it.

How long does a verification decision remain valid?

The verification period is 24 months from the sampling date of the most recent accepted dataset. Continued claim use after expiration requires re-verification using current data. Expired registry entries remain publicly visible and are marked “Expired,” so the record is honest over time rather than quietly disappearing. This reflects the reality of lot-to-lot variability. A result reflects the production it was drawn from, and a credential that is never revisited cannot mean anything at the moment a customer actually checks it.

Conclusion: Turning Existing Data Into Defensible Claims

Many U.S. brands already hold genuinely useful laboratory data. They have commissioned independent testing, spent real money on it, and acted on the results. They often lack a trusted, independently reviewed way to use it, specifically a way to convert a report that says “none detected above 50 µm for these six polymers on this lot” into a claim that survives retailer diligence, regulatory scrutiny, and litigation risk.

The seven-step process described here, which includes defining product scope, reviewing laboratory qualification, assessing method suitability, checking data quality, confirming polymer panel coverage, verifying production period alignment, and obtaining independent third-party review, provides a framework for evaluating what existing data actually supports. The California State Water Board’s drinking-water microplastics framework, with its validated method ranges and defined particle-size fractions, offers a stringent and credible public reference for anchoring that evaluation.

Independent review does not change what the data says. It establishes what the data means, confirms that the method was appropriate, and produces a scope-locked outcome with approved claim language that a brand can stand behind. That difference separates a claim a company merely asserts from a claim a company can substantiate.

Turn real lab data into a claim you can support with WQI’s Plastic-Free Pathway Verification.