Restricted-substance compliance is the least visible part of a product and the fastest to become a problem — a customs hold, a marketplace delisting, a recall. The chemistry is a laboratory's job, not a buyer's. But knowing what is regulated, and how to write a requirement a supplier must answer with documents rather than reassurance, is squarely the buyer's job. This is that part.
The short answer
- Certain azo dyes that can release regulated aromatic amines are restricted in the EU (REACH) and many other markets; related limits cover formaldehyde, extractable heavy metals and nickel release.
- A restricted-substance requirement must name the standard, the limits and the article tested — not just ask 'is it compliant?'
- OEKO-TEX Standard 100 covers many of these substances but is held per article by the mill or dye house, and does not automatically cover trims or a batch it was not issued for.
- For a binding requirement, specify third-party testing on the actual production fabric, with laboratory, method and sample recorded.
What is actually regulated
The best-known restriction covers a group of azo dyes that can break down to release specific aromatic amines classified as harmful. These are restricted under EU REACH for textiles in prolonged skin contact, and comparable rules exist across many markets. Activewear, worn against skin under sweat and friction, sits squarely in the intended scope.
Around that sit several related limits that matter for sportswear: formaldehyde, used in some finishes; extractable heavy metals, which can arrive through dyes and pigments; and nickel release from metal trims such as zip pulls and rivets. Each is a separate test with a separate limit.
The point of listing them is not to turn a buyer into a chemist. It is that 'compliant' is meaningless without saying compliant with what. A requirement that names the substances and the market makes a supplier's answer checkable; a vague one invites a vague reply.
Why a certificate is a starting point, not proof
OEKO-TEX Standard 100 tests against a restricted-substance list that includes regulated azo dyes, formaldehyde and heavy metals, which is why it does useful work here. But the same limits from earlier guides apply. It is held per article, by the mill, dye house or factory — not by a trading partner. It covers the tested article, which may not be your trims. And it expires.
So a Standard 100 certificate is genuine evidence for the fabric it names, held by the company it names, within its validity. It is not a blanket statement that everything in your garment is clear. The zip, the drawcord, the printed logo and any finish added after certification are separate questions.
Read the certificate for holder, product class and validity, then ask the question it does not answer: which components of my garment are outside this certificate, and how are those covered?
How to write a requirement that cannot be dodged
Name four things. The standard or regulation you require compliance with, tied to your market — REACH for the EU, plus any market-specific rules. The specific substances or the referenced restricted-substance list. The components in scope — main fabric, and explicitly the trims and prints. And the evidence you will accept: a certificate for named articles, a test report for the rest, or both.
Then state who tests and on what. For a binding requirement, specify third-party laboratory testing on the actual production fabric and relevant components, with the laboratory name, the test method and a clear sample description on the report. A report that does not describe the sample is not evidence about your goods.
Put the evidence requirement in the purchase terms and tie it to release or payment. A test requested after goods ship is a favour that can be declined; one written into terms is a condition of the order.
The gaps that catch brands out
Trims are the recurring blind spot. A perfectly compliant fabric can carry a zip that fails nickel release, or a rivet that does. On a garment, the regulator does not exempt the metal because the jersey passed.
Prints and finishes are the second. A plastisol print, a bonded logo or a post-dye finish is a separate material added to the garment, and it can carry its own restricted substances. If it was applied after the fabric was certified, the certificate predates it.
The third is the reorder. Compliance evidence covers the batch tested. A reorder from a new dye lot, or after a mill changes a supplier, is a new question — which is why ongoing programs need a written trigger for re-testing rather than a one-time file that ages quietly.
Where we sit in this
None of this is a claim we can make on your behalf. We do not certify chemistry, and no responsible supply-chain partner does. What we do is require Standard 100 fabric from the mills in our programs, verify the certificates rather than filing them unread, and send fabric for third-party testing against the standard a buyer names when a market or customer requires it.
When a buyer's requirement is stricter than a current supplier can document, the supplier does not get a pass because the relationship is comfortable. The work moves to one that can meet it, and the incumbent is told what to obtain to stay on the list.
The deliverable to the buyer is a defensible position: named certificates, test reports in your name, and a documented route to ask for more. Whether a product is ultimately clear is a laboratory's finding — the buyer's job is to hold the evidence, and ours is to make the evidence obtainable.
Quick answers
Are azo dyes banned outright?
No. Only certain azo dyes that can release specific regulated aromatic amines are restricted, and mainly for textiles in prolonged skin contact. Many azo dyes are unaffected. This is why a requirement should reference the regulated amines or a restricted-substance list rather than 'no azo dyes', which is both inaccurate and unanswerable.
Does OEKO-TEX Standard 100 cover restricted substances for the EU market?
It tests against a list that includes many EU-regulated substances, including restricted azo dyes and formaldehyde, per certified article. It is strong evidence for the fabric it names but does not automatically cover trims, prints or finishes added later, and it is not a substitute for a specific test where a market sets a numeric limit you must document.