What is a RoHS homogeneous material?

Directive 2011/65/EU defines a homogeneous material as one material of uniform composition throughout, or a material made from a combination of materials that cannot be disjointed or separated into different materials by mechanical actions.

The Directive's examples of mechanical actions include unscrewing, cutting, crushing, grinding, and abrasive processes. If those actions can separate the item into different materials, each separated material needs its own RoHS assessment.

The current consolidated Annex II lists ten restricted substances and their maximum concentration values tolerated by weight in homogeneous materials. Cadmium has a lower threshold than the other listed substances.

For most listed RoHS substances, the Annex II limit is 0.1% by weight in the homogeneous material. Cadmium is limited to 0.01% by weight in the homogeneous material.

Start with the bill of materials, but do not stop at component names. RoHS evidence should map to the actual materials that can be separated or that remain inseparable after reasonable mechanical actions.

For a cable, that can mean separate evidence for copper or alloy conductors, plating, insulation, filler, shield, jacket, labels, and any coatings. For a printed circuit assembly, it can mean separate records for solder, component terminations, board laminate, component bodies, conformal coating, adhesives, and hardware.

The useful record is not a generic RoHS certificate. It is a material-level trail that shows how the product was split, which Annex II threshold was applied, what declaration or test evidence supports the conclusion, and which exemptions or carve-outs were considered where relevant.

EN IEC 63000:2018 is the harmonised technical-documentation standard referenced for assessing materials, components, and electrical and electronic equipment under Directive 2011/65/EU. Use it as the organizing frame for supplier declarations, test reports, risk assessment, and conformity records.

The most common mistake is treating a supplier's broad product declaration as proof for every material in the part. That declaration may be useful, but it should still map to the homogeneous materials and Annex II thresholds that RoHS actually uses.

Another mistake is testing a mixed sample and treating the result as decisive when one high-risk separable material could be diluted by lower-risk material mass. If the legal question is material-level, the evidence should stay material-level.