OEKO-TEX Standard 100: Classes I-IV Explained 2026

The OEKO-TEX Standard 100 is one of the world's most recognised certification systems for textiles tested for harmful substances. Introduced in 1992 by the German Hohenstein Institute and the International OEKO-TEX Association, the standard sets a global benchmark for textile safety across the entire production chain — from yarn and fabric to finished garments and accessories.

Today, over 35,000 companies in more than 100 countries hold OEKO-TEX Standard 100 certifications. The standard is operated by OEKO-TEX Service GmbH, headquartered in Zurich, Switzerland. It tests for over 1,000 harmful substances and is updated at least once a year to reflect new scientific findings and regulatory changes.

The Four Product Classes of OEKO-TEX Standard 100

The OEKO-TEX Standard 100 does not apply a single set of requirements to all products. Instead, it classifies products into four classes based on their intended use and the degree of skin contact. The more intensive the skin contact and the more sensitive the skin, the stricter the human-ecological requirements and limit values.

A key principle is that products meeting the requirements of a higher (stricter) class automatically satisfy the requirements of all lower classes. For example, fabric certified to Class I can legally be used for Class II, III, or IV products.

Class	Category	Examples	Strictness
Class I	Baby and toddler products (up to 36 months)	Underwear, bodysuits, rompers, baby bedding, terry products, soft toys	Strictest — highest requirements and lowest limit values
Class II	Direct skin contact products	Underwear, bed linen, T-shirts, shirts, blouses, socks, towels, mattresses	High — strict limits for skin-contact materials
Class III	Non-direct skin contact products	Jackets, coats, outdoor wear, suits, linings	Moderate — lower risk of skin contact
Class IV	Decoration and furnishing materials	Curtains, tablecloths, upholstery fabrics, wall coverings, carpets	Standard — minimal skin contact expected

Testing Scope: Over 1,000 Harmful Substances

The OEKO-TEX Standard 100 tests for a comprehensive range of harmful substances, including:

• Banned azo dyes — that can release carcinogenic amines
• Formaldehyde — restricted to strict limits
• Heavy metals — including lead, cadmium, nickel, mercury, chromium, and arsenic
• Chlorinated phenols — such as pentachlorophenol (PCP)
• Phthalates — softeners restricted due to endocrine-disrupting properties
• PFAS/PFCs — per- and polyfluorinated chemicals; intentional use banned since 2024
• Organotin compounds — TBT, DBT, and related substances
• Pesticides — residual pesticides on natural fibres
• Polycyclic aromatic hydrocarbons (PAHs)
• Colour fastness — resistance to rubbing, perspiration, and saliva
• pH value — skin-neutral range
• Volatile Organic Compounds (VOCs) — added to Appendix 4 testing scope effective 2025

The standard's criteria are reviewed and updated at least annually. The standard aligns with key global regulations including REACH Annexes XVII and XIV, the ECHA SVHC Candidate List, the US Consumer Product Safety Improvement Act (CPSIA), and China's GB 18401.

Appendix 4 vs Appendix 6: Two Testing Pathways

The OEKO-TEX Standard 100 offers two testing pathways with different levels of rigour:

Aspect	Appendix 4 (Product Safety)	Appendix 6 (Enhanced Performance)
Focus	Standard product safety — harmful substance residues in the final product	Enhanced — "detox" oriented, stricter limits and more substances
Number of substances	Standard catalogue of regulated substances	Extended catalogue with additional substances and tighter limits
Limit values	Standard limits aligned with regulations	Stricter limits, designed for environmentally conscious production
Application	Standard certification pathway for most products	Optional — for companies pursuing "detox" leadership

2025 and 2026 Regulatory Updates

Based on the official OEKO-TEX communication documents, the following significant changes have been implemented or will take effect:

Change	Effective Date	Impact
"Organic" and "GMO-free" labels for cotton removed	1 April 2025	Cotton products can no longer use "organic" or "GMO-free" claims under Standard 100. Use OEKO-TEX Organic Cotton instead.
VOC (Volatile Organic Compounds) added to Appendix 4	1 January 2025	VOC testing now standard in Appendix 4 scope
Microplastics in glitter monitored	1 April 2025	Glitter containing microplastics added to monitoring scope
Pre-consumer PET bottles no longer accepted as recycled source	1 April 2025	Pre-consumer PET not recognised as recycled material for Standard 100
Upstream certificate policy change	1 June 2026	Renewal: only direct supplier certificates accepted (transition until June 2027)
Wet process certification requirement	1 June 2026	Renewal: all wet processes (dyeing, washing, printing, finishing) must be certified (transition until June 2027)
RSL removed from standard file	2026	Restricted Substances List now provided as separate Excel file

Certification Process

The OEKO-TEX Standard 100 certification process follows these steps:

1. Application — Submit an application form and material sample to an authorised OEKO-TEX institute (such as Hohenstein, TESTEX, or other member institutes).
2. Sample verification — The application and sample are verified for completeness.
3. Testing — The laboratory defines testing criteria, develops an individual measurement plan, and tests the sample for all applicable harmful substances based on the product class.
4. On-site visit — An OEKO-TEX auditor inspects the production facility to evaluate quality assurance measures.
5. Report — A detailed test report is delivered.
6. Certificate — The certificate is issued, valid for one year. Renewal requires annual testing and on-site visits.

The certification covers all components of a finished product — not just the outer fabric but also sewing threads, linings, prints, labels, zippers, buttons, rivets, and other non-textile accessories. All parts must meet the applicable criteria for the product class.

FAQ: OEKO-TEX Standard 100 Common Questions

Conclusion

The OEKO-TEX Standard 100's four-class system provides a clear, scientifically based framework for textile safety. By matching testing stringency to the product's intended use and degree of skin contact, the standard offers practical protection where it is needed most — while avoiding unnecessary over-testing for low-risk applications.

With its annual updates, alignment with global regulations, and testing scope of over 1,000 substances, the OEKO-TEX Standard 100 remains the original and most widely trusted benchmark for harmful-substance-free textiles worldwide.