Azo Dye Testing and Restricted Colourants
Azo dyes that can release carcinogenic amines are banned in most markets, and testing is expected on any dyed or printed product.
This guide explains the underlying principle, the numbers that matter and the checks that keep results consistent.
Chemical background
Certain azo colourants can break down into aromatic amines classified as carcinogenic under EU and other regulations.
It rarely appears on a packaging claim, yet it shapes how the garment feels in the first hour of wear.
Test principle
The sample is chemically reduced, and released amines are extracted and analysed by chromatography.
Keep the specification on one page with a diagram for measurement points, so it cannot be interpreted in two ways.
- Agree tolerances in writing before the first sample is made
- Define the measurement condition and the direction measured
- Review the limit each season against real performance data
Coverage of the test
The test covers the specific regulated amine list, not all dyes, so test reports should name the method used.
Log adjustments and their reasons, which turns each production run into useful data for the next one.
Risk areas in production
Bright direct dyes on cellulose, cheap pigment pastes and uncontrolled dye purchasing carry the highest risk.
Include the same test in the pre-production approval checklist to avoid testing after the goods are shipped.
- Record settings and raw material lots for every approved production run
- Check in-process rather than relying on final inspection
- Escalate deviations the same day they appear
Supplier control
Dye suppliers should provide compliance statements against the current restricted substances list for each colour.
Document what is included in the price, including testing, packing and documentation, to keep comparisons fair.
Summary
Buyers who verify rather than assume obtain better fabric at the same price, and fewer surprises after the goods arrive.
