Azo colourants are a large family of synthetic dyes. Most are not a concern, but some can break down, under certain conditions, into aromatic amines that are classified as carcinogenic. The EU restricts them in REACH Annex XVII, entry 43. The summary below reflects ECHA’s published material; check the current legal text with a qualified adviser for your market.

What the entry says

Entry 43 prohibits azo colourants that can release one or more of the aromatic amines listed in Appendix 8 of Annex XVII, in detectable concentrations, meaning above 30 mg/kg, in the articles or in the dyed parts of the articles. It applies to textile and leather articles that may come into direct and prolonged contact with human skin or the oral cavity, and clothing is within that group. ECHA publishes the list of aromatic amines in Appendix 8.

What it means for knitwear

Tees, underwear, hoodies and leggings are clothing that touches skin, so the restriction is relevant. The test looks at whether the finished dyed fabric or garment can release the listed amines under a defined reductive procedure. Prints and coloured trims or threads are also dyed parts to consider.

How compliance is shown

The usual route is a lab report for the dyed fabric or garment using the EU’s harmonised methods, which are EN ISO 14362-1 and -3 for textiles. Ask the fabric mill for a current report that covers each colour or colour group you sell and that names the method and the limit. Ask dye houses for information on the dye classes they use, and require them to tell you if a dye changes.

Certificates and labels

A separate scheme such as OEKO-TEX STANDARD 100 includes limits for amines from azo colourants among its criteria, but a certificate covers only the products, scope and dates it names. Verify it on the issuer’s check tool and do not treat it as a general approval.

What to answer the buyer

Reply with the supplier reports and the list of styles they cover, and keep them updated when fabric or dye sources change. Do not sign a broad declaration you cannot support: say which styles, colours and reports it covers, and state the date. If a colour is not yet covered by a report, order the test before the first shipment, since a test report is much cheaper than a rejected consignment or a delisted style.