What is ZDHC? ZDHC (Zero Discharge of Hazardous Chemicals) is a global initiative that helps the textile, footwear, and related industries control—and eventually eliminate—hazardous chemicals in their supply chains.
Execution via key tools: ZDHC MRSL V3.1 (List of banned/restricted substances in production) ZDHC Gateway – Chemical Module (declaration and verification of chemical conformity levels), and ZDHC Wastewater Guidelines (Wet plant wastewater control). Source updated: roadmaptozero.com.
3 things you need to remember
- MRSL ≠ RSL: MRSL blocks toxins during the production process (workers & environment); RSL controls residue limits in finished products.
- Gateway + Level 0–3: Chemicals are subject to MRSL (Material Safety Data Sheet) verification, ranging from self-declaration to in-depth assessment — brands typically specify minimum levels for each chemical group.
- Input + associated wastewater: Wet plants require clean inventory (InCheck/ChemCheck) and ETP operation that adheres to Wastewater Guidelines, not just "outlet testing".
When international buyers or brands ask, “Is the factory compliant with ZDHC?”, they typically want to see the chemical input management system and wastewater records—not just a marketing statement. This article explains. What is ZDHC?This includes frequently used modules, Level tables, and the differences between MRSL and RSL, so that you (purchasing, QA, ETP) can speak the same language as the buyer. The content is for guidance only; it does not replace auditors, brand guidelines, or internal SOPs.
What is ZDHC in the textile supply chain?
ZDHC write in full Zero Discharge of Hazardous Chemicals — A roadmap toward zero hazardous chemical emissions in the fashion supply chain and related industries (wet dyeing, leather goods, some wet-process processes). ZDHC is not just "a single certificate affixed to the factory" like ISO; it is Toolkit + tutorial Operated by the ZDHC Foundation and the brand/supplier community, and adopted by brands through supplier codes.
Three areas you'll frequently encounter:
- Input chemicals: Production Restricted List (MRSL), inventory, and reconciliation on Gateway.
- Chemical supplier: The appropriate level depends on the product/formulation, lab records, and formulation management.
- Wastewater (wet plant output): Wastewater Guidelines — these are parallel to Vietnamese National Technical Regulations/environmental permits and are not interchangeable.
If you want to implement a checklist at the factory (inventory, ChemCheck, WW vs QCVN), you can read more about the operating instructions on the official website. ZDHC deployment in textile dyeing factoriesThis article focuses on answering the question "what is it / what tool is it / how is it different from RSL".
Three commonly used ZDHC tools
1) ZDHC MRSL (Manufacturing Restricted Substances List) — list of banned or restricted substances during the production processThe currently popular deployment version is: MRSL V3.1When the brand or InCheck requests "follow the new MRSL," you and the NCC should agree on version 3.1 (and accompanying guidance), no longer considering version 2.0 as the latest. Always download the official list/PDF before each audit — the Foundation may update the version number.
2) ZDHC Gateway – Chemical Module — A platform for listing and finding chemicals/suppliers at the appropriate MRSL level. This is where buyers often request "searchable/level-based" products before finalizing a batch.
3) ZDHC Wastewater Guidelines — Wet plant wastewater control framework (parameters, frequency, sampling method according to guidance). In Vietnam, plants must still comply with applicable permits and Vietnamese National Technical Regulations; ZDHC WW is a brand/chain class, not a substitute for domestic legal framework.
In addition, there are operational concepts: CIL (chemical inventory list) InCheck (Compare plant inventory with MRSL/Gateway) ChemCheck (This relates to chemical products, not "certification of the entire textile factory").
Gateway Level Chart
Level reflects the degree of completeness of the application/verification. chemical products Compared to MRSL — this does not mean "the entire textile factory has reached Level N". Brands may require different minimum levels for dyes, aux, ETP chemicals, etc.
| Level | Summary of meaning | Factory & Procurement Perspective |
|---|---|---|
| Level 0 | Self-declaration on Gateway | Initial stage; no in-depth third-party verification yet. |
| Level 1 | Profile + lab testing/verification according to guidance | Suitable when beginning to demonstrate that MRSL has evidence. |
| Level 2 | Product stewardship system based on MRSL | Deeper Formula & Process Control - Level 1 |
| Level 3 | Comprehensive assessment, often involving on-site audits using Conformance Guidance. | Many major brands prioritize this level; some third-party certifications may be mapped equivalents — always ask for the buyer code. |
Guidelines. The terminology for Level/Conformance may be updated by ZDHC — refer to official documentation and brand requirements prior to audit.
What is the difference between MRSL and RSL?
Two lists are often confused in buyer email lists. Remember this one thing: MRSL monitors chemicals during production; RSL monitors residue on finished products.
| Criteria | ZDHC MRSL | RSL (Restricted Substances List) |
|---|---|---|
| Subject | Chemicals used in manufacturing (input) | Remaining above finished product (final article) |
| Target | Protecting workers, the community, and the environment at the factory. | Consumer safety & legal compliance / label brand |
| Typical tools | MRSL V3.1Gateway, InCheck/ChemCheck | RSL brand, REACH/CPSIA, OEKO-TEX® Standard 100… |
| Who is the main operator? | Wet mills, chemical supplier, wet-process mills | Brand, retailer, lab test finished product |
| Consequences of failing | Inventory shows "red", InCheck fails, buyer blocks purchase/transaction. | Airline exports, recalls, RSL lab complaints |
The factory might pass RSL on finished products but still fail ZDHC testing if the inventory still contains banned substances on MRSL V3.1. Conversely, cleaning the input reduces both environmental and residual risks — but RSL testing still needs to be done separately according to brand requirements.
Why are textiles and footwear pushing ZDHC?
Wet industries (dyeing, printing, washing, tanning, etc.) use many chemicals and generate COD, color, metal, and salt loads. Global brands are under pressure from NGOs, ESG, and transparent supply chains, so they shift these requirements down to the mill through supplier guidelines: clean inventory, minimum levels, and wastewater reporting according to Wastewater Guidelines.
In Vietnamese factories, ZDHC typically appears when:
- You sew/manufacture for brands or exporters with ZDHC/MRSL codes.
- Audit social/chemical or customer audit ask CIL, SDS, InCheck.
- Expanding EU/US/JP orders — buyers should include “chemical compliance” in the purchase order conditions.
Practical benefits: reduced risk of order cancellations due to "black market" chemicals, standardized purchasing, and forcing ETPs to operate more reliably — not just "having a license".
The role of factories and chemical suppliers
Mill: Build and update CIL; request batch SDS/COA; prioritize codes already on the Gateway that match the required brand level; perform InCheck; operate ETP and take WW samples according to the brand schedule and Vietnamese legal requirements; do not mix "unknown source chemicals" into the wet line.
Chemical supplier (NCC): Supply the correct grade; COA/MSDS by batch; support for registration/ChemCheck or MRSL document packing. when requested by orderChemCheck and Level are attached. Kosmos's products — This should not be interpreted as "NCC declaring the entire catalog to be Level 3".
Brand / buyer: Confirm the MRSL version (actually: V3.1), minimum level, WW frequency, and required tool code. You should request a written guideline instead of just listening to the salesperson.
Loc Thien Chemicals No Claim blanket “ZDHC Level N / Supplier to Zero” for the entire product range. We support COA, MSDS/SDS by batch and pack according to ZDHC/MRSL/ChemCheck guidelines. as per order when requested by the client/brand..
Process chemicals and ETP are often associated with each other.
ZDHC places strong emphasis on the dye/aux/finishing group, but the wet line and ETP still require stable chemical processes and clear batch records. These are the groups most frequently encountered in textile dyeing operations:
- Alkaline mercer / scour / pH neutralizer: xem caustic soda NaOH — Concentration and COA are important when changing grades between batches.
- Acid process / pH adjustment: hydrochloric acid (HCl) — pH deviation affects both the line and the ETP.
- Deoxidation/Oxidation: hydrogen peroxide H₂O₂ — Residual oxidation can affect subsequent flocculation.
- ETP flocculation/sedimentation: FeCl2 (iron(II) chloride), PAC ~31% — Re-test jar when changing the source or percentage according to COA.
Quick overview of industry categories: textile dyeing chemicalsThe selection of process/ETP no change Cleaning inventory dye/aux according to MRSL V3.1 — these two tasks must go hand in hand.
B2B profile when brands inquire with ZDHC
When an RFQ or audit asks for “ZDHC support”, the practical package usually includes:
- COA by batch (concentration, primary parameters).
- Current version of MSDS/SDS, correct trade name/grade.
- Packing/shipment, internal code matches factory CIL.
- MRSL/Gateway/ChemCheck instruction manual pack if the brand specifies the Level or tool — Write it on the application form, do not infer it from the catalog.
Please include: chemical name, concentration/grade, volume, delivery location, and a snippet of your brand requirements (MRSL V3.1, minimum level, whether a searchable gateway is needed). B2B pricing is based on your needs — no fixed prices are listed in the post.
Need textile chemicals / ETP with COA–MSDS and supporting documentation according to brand requirements?
Loc Thien Chemicals partners with B2B: see hoachatlocthien.com category textile dyeing chemicals Soft SKU: FeCl2, CAP, NaOH, HCl, H₂O₂.
Technical/Purchasing Hotline: (+84) 979 891 929.
Top Q&A
What does ZDHC stand for?
Zero Discharge of Hazardous Chemicals — A global roadmap toward controlling and eliminating hazardous chemicals in the textile, footwear, and related industries supply chains. Enforcement through MRSL, Gateway, and Wastewater Guidelines, not just a single "label."
Which version of MRSL is most commonly used?
The current widespread implementation is: ZDHC MRSL V3.1No longer consider V2.0 as the "latest version". Before each InCheck/Audit, download the official list and guidance; the brand can confirm the correct version in the supplier code.
What is the difference between MRSL and RSL?
MRSL limit substances in manufacturing (Protecting workers and the factory environment). RSL limit residue finished product (Consumer/label law). Passing one party does not automatically pass the other.
What do Levels 0–3 on the ZDHC Gateway mean?
Level describes the level of documentation/verification. chemical products Compared to MRSL: from self-declaration (0) to in-depth assessment/audit (3). This is not a certification of "the entire textile factory achieving Level 3". Brand specifies the minimum Level according to the group.
Is ChemCheck a factory certification?
Is not. ChemCheck affixes MRSL-referenced formulations/chemical products. The plant still needs CIL, InCheck, proper operation, and batch records. Don't confuse "supplier with a ChemCheck code" with "all chemicals on the line are clean."
Do the Wastewater Guidelines replace the Vietnamese National Technical Regulation (QCVN)?
No change. ZDHC Wastewater Guidelines is a brand/chain grade. The Vietnamese plant still complies with applicable environmental permits and Vietnamese National Technical Regulations. In practice, you operate to meet these requirements. both When the buyer requests ZDHC WW.
Where did the factory begin implementing ZDHC?
Suggested order: (1) Get supplier guideline brand — finalize MRSL V3.1 and Level; (2) build a complete CIL; (3) type/replace risk code; (4) request COA/SDS + Level/Gateway as per order; (5) InCheck; (6) scan ETP/WW. For detailed checklist, see the implementation article on hoachatlocthien.com.
How does NCC chemical support ZDHC?
Practical: correct grade, batch COA/MSDS, support for MRSL/ChemCheck packs. when the brand requires it to be made to order.The general statement "achieved ZDHC" without specifying the Level, MRSL version, or product code should not be accepted. Contact Loc Thien: (+84) 979 891 929 · hoachatlocthien.com.
This content serves as a reference guide for procurement, QA, and wet plant operations. It does not replace auditor, brand guidelines, Conformance Guidance official documents, or Vietnamese environmental legislation. Always refer to ZDHC Foundation/roadmaptozero documents and request buyer input before auditing.
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