Textile Chemical Testing: OEKO-TEX, GOTS, and ZDHC Compliance

Textile chemical safety is a critical concern for brands, retailers, and consumers. Harmful substances in clothing can cause skin irritation, allergic reactions, and long-term health effects. OEKO-TEX, GOTS, and ZDHC are three major frameworks addressing chemical compliance in textiles. This guide explains testing requirements and certification processes.

Figure 1: Textile chemical testing laboratory with sample preparation

Figure 2: Chromatography analysis for harmful substance detection

OEKO-TEX Standard 100

OEKO-TEX Standard 100 tests for harmful substances in textile products:
• Product Classes: Class I (baby), Class II (skin contact), Class III (no skin contact), Class IV (decoration)
• Tested Substances: Illegal substances, regulated substances, harmful but not regulated, precautionary parameters
• Key Limits: Formaldehyde (max 16-75 ppm), pH value (4.0-7.5/9.0), heavy metals, pesticides, chlorinated phenols
• Certification: Valid 12 months, requires annual renewal testing
• Labeling: License number and testing institute on hangtag

GOTS (Global Organic Textile Standard)

GOTS is the leading standard for organic textiles:
• Fiber Content: Minimum 70% organic fibers (GOTS label grade) or 95% (organic label grade)
• Chemical Inputs: Strict positive list for dyes, auxiliaries, and finishes
• Prohibited Substances: Aromatic solvents, chlorinated bleaches, heavy metals, formaldehyde, GMOs
• Wastewater Treatment: Required for wet processing units
• Social Criteria: Compliance with ILO conventions
• Processing Stages: Covers entire supply chain from fiber to finished product

ZDHC (Zero Discharge of Hazardous Chemicals)

ZDHC focuses on eliminating hazardous chemicals from textile supply chains:
• MRSL (Manufacturing Restricted Substances List): Chemical formulations restricted in manufacturing
• Conformance Levels: Level 1 (self-declaration), Level 2 (third-party review), Level 3 (EMR chemical inventory)
• ClearStream: Wastewater and sludge testing program
• InCheck: Chemical inventory verification
• Performance InCheck: ZDHC MRSL conformance scoring

Common Textile Chemical Tests

Extractable Heavy Metals: Lead, cadmium, mercury, chromium (VI), arsenic, antimony
Formaldehyde Content: Colorimetric or chromatographic methods
Pesticide Residues: GC-MS analysis for organochlorine, organophosphorus compounds
Chlorinated Organic Carriers: GC-MS detection
Phthalates: GC-MS or LC-MS analysis
Azo Dyes (Banned Amines):** LC-MS/MS after reductive cleavage
Alkylphenol Ethoxylates (APEOs):** LC-MS/MS analysis
Perfluorinated Compounds (PFCs):** LC-MS/MS or GC-MS