How Textile Suppliers Prove Chain of Custody: A Technical Deep Dive into Transaction Certificate Workflows for GRS, GOTS, and BCI Certified Fabrics

Textile suppliers prove chain of custody certification by generating and exchanging Transaction Certificates (TCs) at every point a certified material changes hands, from raw fiber through processing, weaving, and final sale. These TCs, issued by accredited certification bodies under standards like GRS, GOTS, and BCI, serve as the documentary proof that a certified claim, such as "100% recycled polyester" or "organically grown cotton," is accurate and unbroken throughout the supply chain. Without a valid TC workflow, no certified label claim is legally or commercially defensible.

TL;DR

• Transaction Certificates (TCs) are the core mechanism proving chain of custody in certified textile supply chains.

• GRS, GOTS, and BCI each have distinct TC workflows, scope certificate requirements, and eligible chain-of-custody models.

• A single missing or expired TC anywhere in the chain invalidates the certified claim for the entire product.

• Digital traceability platforms are replacing paper-based TC systems, reducing fraud risk and compliance gaps.

• Brands sourcing certified materials must audit their suppliers' TC documentation, not just their scope certificates.

What Exactly Is Chain of Custody in a Textile Supply Chain?

Chain of custody is the documented, verified sequence of ownership and handling of a certified material from its origin to its final product form. According to Textile Exchange, chain of custody ensures that claims about fiber content, such as "organically grown" or "recycled," are accurate at every stage of production. It is not a single certificate but a connected series of records that must remain intact across every actor in the supply chain.

In practical terms, this means a bolt of GRS-certified recycled polyester lining must carry verifiable documentation from the recycled bottle collector, through the chip extruder, yarn spinner, weaver, dyer, and finally to the garment manufacturer. A gap at any one of these nodes breaks the chain entirely.

"Fashion brands must demonstrate that their chain of custody not only exists but is also accurate, authentic and responsible." - Logility

According to Tracex, mapping the full textile value chain from fiber to fashion is now a prerequisite for credible ESG compliance and sustainable sourcing, not just a branding exercise.

How Do Transaction Certificates Actually Work for GRS, GOTS, and BCI?

A Transaction Certificate (TC) is a document issued by an accredited certification body that confirms a specific shipment of certified goods has been sold and transferred in compliance with the relevant standard. Each standard has its own TC rules, eligible models, and scope certificate prerequisites.

Standard	TC Issuing Body	CoC Models Allowed	Key TC Trigger	Label Claim Enabled
GRS (Global Recycled Standard)	Approved CB (e.g., Control Union)	Identity Preserved, Segregated, Mass Balance	Each sale of certified material	"Recycled Content X%"
GOTS (Global Organic Textile Standard)	Approved CB (e.g., Control Union)	Identity Preserved, Segregated only	Each sale of certified material	"Organic" or "Made with Organic"
BCI (Better Cotton Initiative)	BCI Secretariat / licensed ginners	Mass Balance (volume-based credits)	Seasonal volume claims	"Sourced as Better Cotton"

The GRS Certification Process and TC Workflow

The GRS certification process begins with a facility obtaining a Scope Certificate (SC) from an accredited certification body, confirming it is eligible to process and sell GRS-certified recycled materials. Recycled polyester certification under GRS, for example, requires the supplier to verify the pre- or post-consumer waste origin of the input material before any TC can be generated.

Once an SC is active, a TC is triggered for every individual sale transaction involving certified goods. The TC must reference the buyer's SC, the seller's SC, the volume sold, and the recycled content percentage. Critically, the buyer cannot issue a TC to their own downstream customer unless they hold a valid SC themselves.

The GOTS Transaction Certificate Workflow

GOTS certification requirements are stricter than GRS in one important respect: GOTS does not permit mass balance as a chain-of-custody model. Every kilogram of GOTS-certified cotton or organic fiber must be physically separated from non-certified material throughout processing. This makes the GOTS transaction certificate workflow more operationally demanding but also more credible as a claim.

A GOTS TC must include the product category, fiber composition, processing stage, and the certification grade (either "Organic" for 95%+ certified content, or "Made with Organic" for 70-94%). The GOTS TC is generated through the GOTS Online Database, providing a publicly verifiable audit trail.

BCI's Volume-Credit Model

BCI operates differently. Rather than tracking physical bales of Better Cotton, it uses a mass balance credit system where volume purchased by a brand is matched against Better Cotton grown by farmers in the same season. This means no physical TC accompanies a BCI shipment in the same way as GRS or GOTS. Instead, brands receive a Claim Unit (CU) allocation through the BCI platform. This is a pragmatic model for scaling sustainable cotton adoption, but it means BCI cannot support a "this specific fabric contains Better Cotton" claim at the fiber level.

What Are the Most Common Chain of Custody Failures in Practice?

Understanding where CoC workflows break down is more instructive than knowing how they work when everything goes right. According to an OECD study on sustainability certifications in the garment sector, certificates of origin and chain of custody documentation are frequently cited as gaps in due diligence, even among brands with formal supplier compliance programs.

The most common failure points include:

• Expired Scope Certificates: A supplier's SC lapses but TCs continue to be issued, invalidating all downstream claims.

• Missing intermediate TCs: A brand holds TCs from fiber to yarn and from fabric to garment, but the yarn-to-fabric TC is absent. The chain is broken.

• Incorrect CoC model application: A supplier uses mass balance for GOTS-certified material, which is not permitted under GOTS rules.

• Volume discrepancies: The TC states 5,000 meters sold, but the purchase order shows 7,000 meters. Auditors flag the gap immediately.

• Subcontractor non-disclosure: A certified weaver subcontracts dyeing to an uncertified mill without disclosure, breaking the CoC at that stage.

As Vogue reported in early 2025, building on Textile Exchange's TrackIt system for electronically tracking certified material custody is increasingly seen as the solution to these manual documentation failures.

How Should Brands Audit Supplier TC Documentation?

Holding a supplier's Scope Certificate is not sufficient due diligence. Brands must request and verify the full TC chain for each certified product they purchase. A practical audit workflow looks like this:

1. Verify the Scope Certificate of every supplier in the chain via the relevant certification body's public database (e.g., Textile Exchange's TrackIt, GOTS Online Database).

2. Request TCs for each transaction from fiber origin to your direct supplier, ensuring no stage is skipped.

3. Cross-reference volumes across TCs to confirm no inflation or discrepancy exists between sold and purchased quantities.

4. Confirm CoC model consistency across all TCs (e.g., all GRS TCs in the chain should use the same model: Identity Preserved, Segregated, or Mass Balance).

5. Check TC issuance dates against shipment dates to confirm the SC was valid at the time of each transaction.

Suppliers like Sungil Tex, which hold active GRS and GOTS Scope Certificates through Control Union (GRS/GOTS License CU 1022128) and BCI membership (Member ID 1009257), simplify this process by maintaining complete, audit-ready TC documentation for every certified product in their range. For brands supplying to markets with mandatory supply chain disclosure requirements, this level of documentation readiness is increasingly a baseline expectation, not a differentiator.

What Is the Difference Between a Scope Certificate and a Transaction Certificate?

These two documents are frequently confused but serve entirely different functions:

Document	What It Proves	Issued By	Validity Period	Public?
Scope Certificate (SC)	A facility is certified and eligible to process/sell certified materials	Certification Body	Typically 1 year	Yes (public databases)
Transaction Certificate (TC)	A specific shipment was sold in compliance with the standard	Certification Body	Per transaction	Varies by standard

An SC without TCs proves a company is capable of selling certified goods. TCs without a valid SC are meaningless. Both are required to make a defensible certified claim.

Frequently Asked Questions

Q: Can a brand use a supplier's Scope Certificate as proof of chain of custody?

No. A Scope Certificate only confirms a supplier is eligible to process and sell certified materials. Transaction Certificates are required to prove that a specific shipment was actually transferred in compliance with the standard. Both documents are necessary.

Q: What is the difference between GRS and GOTS for recycled polyester certification?

GRS (Global Recycled Standard) governs recycled content claims for materials like recycled polyester, recycled nylon, and other post-consumer or pre-consumer waste inputs. GOTS governs organic natural fibers like cotton and wool. Recycled polyester certification falls exclusively under GRS, not GOTS.

Q: How many TCs are typically needed for a GRS-certified lining fabric?

At minimum, four to five TCs are needed: recycled input material to chip extruder, chip to yarn spinner, yarn to weaver, fabric to dyer/finisher, and finished fabric to the brand or garment maker. Each transaction in the chain requires its own TC.

Q: Does BCI certification require Transaction Certificates?

BCI uses a volume-credit (mass balance) model rather than physical TC tracking. Brands receive Claim Units through the BCI platform rather than product-specific TCs. This means BCI cannot support a physical fiber-level traceability claim the way GRS or GOTS can.

Q: What happens if a TC is missing for one stage in the supply chain?

The certified claim is broken for the entire product. A complete, unbroken TC chain is required. A single missing TC, even at an intermediate processing stage,