What Does OEKO-TEX Certification Mean for Curtains? (Standard 100 Decoded, 2026)

OEKO-TEX Standard 100 is the chemical-safety baseline for textiles, not an organic label. That single sentence resolves most of the confusion on curtain product pages, where “OEKO-TEX certified” is sometimes presented as if it covered the fiber’s origin, the factory’s labor practices, or the dye’s plant base. It does none of those things. It tests what is on the finished fabric, in regulated parts per million, against a published substance list updated each January.

This guide walks what Standard 100 actually tests, the four product classes, how to verify a certificate number on the official tool, and how OEKO-TEX compares to GOTS and Made in Green. For the wider context on natural fiber and sustainable picks, our sustainable and natural fiber curtains hub maps every certified spoke in the Two Pages catalog.

What OEKO-TEX Standard 100 Actually Tests

What is OEKO-TEX Standard 100?

OEKO-TEX Standard 100 is an independent certification system for raw, semi-finished, and finished textiles, run by the OEKO-TEX Standard 100 official scope. Every component of a certified article (the fabric, the thread, the buttons, the linings) must pass laboratory testing before the finished product earns the label.

The system was founded in 1992 in Zurich and Vienna and is operated by a network of 17 independent textile institutes across Europe and Japan. Each institute issues certificates under the same global protocol, which is updated annually in January as new substances are added to the regulated list.

What substances does OEKO-TEX Standard 100 test?

The protocol covers more than 1 000 regulated substances per kilogram of textile, organized into chemical families. The list is broader than what most national regulations require, which is why some markets accept the certificate as a passing equivalent for textile safety.

Colorfastness and skin-friendly pH are also tested. A Class I textile must hold its dye against perspiration, water, and rubbing, and must sit within a pH range of 4.0 to 7.5 to avoid skin irritation. Failing any family bumps the article down a class or denies certification entirely.

What are the 4 OEKO-TEX product classes?

The class drives the test severity. A Class I curtain is harder to certify than a Class IV curtain because the limits are tighter, the colorfastness scope is broader, and the formaldehyde cap drops by almost 20x between the two ends of the scale.

Product class	Scope	Formaldehyde cap	Typical curtain match
Class I	Babies and toddlers under 3 years, skin-contact	16 ppm	Nursery panels, swaddles, crib accessories (rare on curtain lines)
Class II	Direct skin contact, adult	75 ppm	Lined curtains, bedroom panels touched by occupants regularly
Class III	No or limited skin contact	300 ppm	Jackets, outerwear, structured panels rarely touched
Class IV	Decoration materials	300 ppm	Most unlined living room curtains, upholstery, table linen

Most curtain catalogs sit at Class II or Class IV depending on whether the buyer treats the panel as a skin-contact item (bedroom, child’s room) or a decoration item (formal living room). A vendor that does not state the class is hiding the test severity.

Is OEKO-TEX Standard 100 the same as organic?

No. Standard 100 tests the finished fabric for harmful residue. Organic is a fiber-origin claim that requires the cotton, linen, or wool to be grown without synthetic pesticides and processed under specific rules. A 100% polyester curtain can carry OEKO-TEX Standard 100, but it cannot carry GOTS or any organic certification because polyester is petroleum-derived.

The practical consequence: a Liz Linen panel from Two Pages, which is a 10% linen / 90% polyester blend, holds OEKO-TEX Standard 100 at the fabric level. That tells you the chemistry is safe. It does not tell you the fabric is sustainable in the broader fiber-origin sense. For that, you stack additional certifications on top.

OEKO-TEX vs Other Certifications

OEKO-TEX vs GOTS: which one for curtains?

The choice splits by fiber. For cotton curtains, GOTS is the priority because it certifies organic cultivation, low-impact processing, and fair labor. For linen curtains, OEKO-TEX Standard 100 paired with European Flax is the working stack because organic linen cultivation is rare and the European Flax scheme already covers field-of-origin traceability.

Think of OEKO-TEX as the chemistry floor and GOTS as the agriculture and labor scope. Neither replaces the other. A panel that carries both is the most complete credential package available in 2026.

Made in Green by OEKO-TEX: how is it different?

Standard 100 covers only the chemistry of the finished textile. Made in Green by OEKO-TEX standard adds two layers on top: the production facility must be STeP (Sustainable Textile Production) certified, and the consumer can scan a QR code on the hangtag to trace the full supply chain from fiber to finished product.

Made in Green is the more demanding tier. It signals chemical safety and social and environmental factory standards. Most curtain lines (Two Pages included) carry Standard 100 only, not Made in Green. The label appears more often on activewear and bedding than on window treatments.

European Flax + OEKO-TEX: when both apply

For linen curtains, the ideal stack is European Flax certification on the fiber plus OEKO-TEX Standard 100 on the finished fabric. The first guarantees the flax grew in Western Europe with mechanical retting, GMO-free, and traceable to the field. The second guarantees the final dyeing and finishing did not reintroduce regulated substances above safe limits.

How to Verify a Certification Number

Where is the OEKO-TEX number on the product?

The certificate ID appears on the product page (under “specifications” or “certifications”), on the hangtag attached to the panel, and on the supplier’s official data sheet. The format follows a fixed pattern: a 2-letter country code, a 4 or 5 digit number, and a 1-digit institute code. Example: AT-12345-1 (Austria institute, number 12345).

If the seller mentions OEKO-TEX without publishing the ID, the claim is unverifiable. Ask for the number directly. A legitimate certified seller can provide it within one business day from the product manager.

How to use the OEKO-TEX label check tool

Enter the certificate ID into the OEKO-TEX label check tool. The free tool returns the certificate holder name, the product class, the expiry date, and the scope of items covered. The scope line matters: a certificate can cover only the yarn, only the unfinished fabric, or the full finished product. Match the scope to what you are buying.

What greenwashing red flags to watch for

Five flags appear repeatedly on curtain product pages and should trigger a follow-up question before purchase.

OEKO-TEX for Nurseries and Sensitive Skin

Why Product Class I matters for baby rooms

Picture the 6 am sunbeam on a crib at 18 inches from a curtain panel. That is the contact distance OEKO-TEX models in Class I limits, and it is why the formaldehyde cap drops to 16 ppm versus 75 ppm for adult skin-contact textiles and 300 ppm for decoration. The infant respiratory and dermal systems are more sensitive to off-gassing and skin transfer than adult systems.

Allergy-sensitive adults and pet households

Atopic dermatitis, contact eczema, and household pet sensitivities all benefit from Class I or Class II panels because the residual surfactants, formaldehyde from wrinkle-resistant finishes, and disperse dye traces are kept lower than the unmarked baseline. A Class IV decoration panel may pass national safety regulations but will sit closer to the upper limit on every test family.

For households where allergies drive the purchase, the combined audit is: Class I or II Standard 100 certificate, unlined or linen-lined construction, and a request for low-VOC dye batch at checkout. Polyester linings reintroduce volatile compounds that the panel itself does not contain, which is why the lining choice matters as much as the fabric class.

Two Pages SKUs That Carry OEKO-TEX

Two Pages currently has three collections that touch OEKO-TEX at different scopes. Here is what each one actually covers, with no embellishment of the scope.

Liz Linen Drape Pleated (Standard 100 fabric-level)

Liz Linen is the cleanest OEKO-TEX entry in the Two Pages catalog. The certification applies at the finished fabric level, which is the broadest practical scope: the dyeing, finishing, and slub-texturing all sit inside the certified protocol. The composition is 10% linen, 90% polyester, weight is 350 gsm heavyweight, and the panel is anti-wrinkle and colorfast for daily skin-contact use.

Pricing starts at $59.99/panel, lead time is 7 to 10 business days for in-stock colorways, and nine muted colorways are available (Snow White, Ivory White, Sand Beige, Light Khaki, Burlywood Birch, Grey Beige, Tapioca, Taupe Grey). For a buyer who prioritizes the certification over the fiber purity, Liz is the most explicit choice.

Doris 100% European Flax (OEKO-TEX yarn baseline)

Doris is the certification stack pick for buyers who want pure linen with traceability. The flax is 100% European Flax grown in France and Belgium, certified Masters of Linen (field-to-loom in Europe), and the yarn carries OEKO-TEX at the spinning stage. The fabric-level OEKO-TEX scope is narrower than Liz because the post-spinning dyeing happens outside the OEKO-TEX certified line.

Weight is 117 gsm light-filtering, pricing starts at $109/panel, lead time is 10 to 12 business days, and six natural colorways are available. The full Doris European Flax honest review walks the drape behavior, the dye batch consistency, and owner feedback after the first wash cycle.

Patti Premium 100% Belgian Flax (yarn-level)

Patti is the entry tier for real-linen credentials in the Two Pages lineup. The fiber is 100% Belgian Flax Linen with OEKO-TEX certification at the yarn level (same scope as Doris). Weight is 140 gsm medium, pricing starts at $79.99/panel, and nine muted colorways are available.

The “Premium” wording is a brand label, not an independent quality tier. The linen is legitimate Belgian Flax, but the certification stack does not include Masters of Linen (which would require European spinning and weaving in addition to European cultivation). For buyers whose budget caps the Doris pick, Patti is the working compromise.

The honest read across the three: if the goal is the most explicit OEKO-TEX coverage, Liz Linen wins on scope (fabric-level beats yarn-level). If the goal is the most credentialed natural fiber, Doris wins on the European Flax and Masters of Linen pair stacked on top of OEKO-TEX yarn. Both routes are legitimate, and the choice depends on whether the priority sits closer to chemistry guarantees or fiber-origin guarantees. For the wider decision tree, the sustainable curtains hub maps every certified spoke in one place.

FAQ

What does OEKO-TEX Standard 100 actually mean on a curtain?

OEKO-TEX Standard 100 is a chemical-safety certification that tests the finished textile for over 1 000 regulated substances per kilogram of fabric. On a curtain label, it confirms the panel does not contain harmful levels of formaldehyde, heavy metals, banned aromatic amines, AZO dyes, phthalates, or pesticide residue beyond the limits set for its product class. It does not certify the fiber is organic, the factory uses fair labor, or the dye is plant-based. A Liz Linen panel from Two Pages carries Standard 100 at the fabric level.

Is OEKO-TEX certified the same as organic?

No. OEKO-TEX Standard 100 tests for harmful chemical residue in the finished textile regardless of fiber origin. GOTS certifies that the fiber itself is grown organically and processed without harmful chemicals under fair labor conditions. A polyester curtain can be OEKO-TEX Standard 100 certified, but it cannot be GOTS certified. For organic credentials, look for GOTS on cotton or European Flax on linen, then add OEKO-TEX Standard 100 as the chemistry floor on top.

What are the 4 OEKO-TEX product classes?

Class I covers items for babies and small children under 3 years with a formaldehyde cap of 16 ppm. Class II covers textiles with direct skin contact at 75 ppm. Class III covers textiles with no or limited skin contact at 300 ppm. Class IV covers decoration materials including most unlined curtains. The class determines test severity, so a Class I curtain is harder to certify than a Class IV curtain.

How do I verify an OEKO-TEX certification number?

Find the certificate ID on the product page, hangtag, or supplier’s data sheet. The format is typically a 2-letter country code, a 4 to 5 digit number, and a 1-digit institute code (for example, AT-12345-1). Enter the number into the OEKO-TEX label check tool at oeko-tex.com. The tool returns the certificate holder, product class, expiry date, and scope. If any of those are missing or expired, the claim does not hold.

Are Two Pages curtains OEKO-TEX certified?

Three collections touch OEKO-TEX at different scopes. Liz Linen Drape Pleated carries OEKO-TEX Standard 100 at the fabric level, the most explicit certification in the catalog. Doris 100% European Flax and Patti Premium 100% Belgian Flax carry OEKO-TEX at the yarn level. No Two Pages SKU currently carries Made in Green or Class I. For nursery use, the recommended stack is Liz Linen plus a low-VOC dye request at checkout.

OEKO-TEX vs Made in Green: what is the difference?

OEKO-TEX Standard 100 certifies only the chemistry of the finished textile. Made in Green by OEKO-TEX adds two layers: the production facility must be STeP certified, and the consumer can scan a QR code on the hangtag to see the full supply chain trace from fiber to finished product. Made in Green signals both chemical safety AND social and environmental factory standards. Standard 100 alone says nothing about the factory.

How long is an OEKO-TEX certificate valid?

OEKO-TEX certificates are valid for 12 months from the date of issue and must be renewed annually. Renewal requires re-testing the product against the current year’s substance list, updated each January. A claim made today against a 2024 certificate is no longer valid in 2026. When you check a number on the label-check tool, look at the expiry date first. If the certificate expired more than 90 days ago, treat the claim as unverified.

What greenwashing red flags should I watch for on curtain labels?

Five common red flags. First, “OEKO-TEX tested” without a certificate number is meaningless. Second, “eco-friendly” or “non-toxic” with no certification at all. Third, a real number that returns an expired certificate when checked. Fourth, a Class IV decoration certificate cited for a curtain marketed as nursery-safe (Class I is required for skin-contact baby items). Fifth, a yarn-level certification presented as if it covered the finished fabric, when downstream dyeing in another facility can reintroduce regulated substances.