RoHS and REACH, in plain English
One solder joint can make a compliant-looking product non-compliant, and a product-level average will never show it.
Published · 7 min read · By YCP Team
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Why "homogeneous material" is the whole point
The definition. A homogeneous material is one that cannot be mechanically separated into different materials — by unscrewing, cutting, crushing, grinding or abrading. A cable is not a homogeneous material; the copper, the insulation and the sheath each are. A plated contact is not; the base metal and each plating layer are.
So the limit bites at a level most people do not test at. 0.1% by weight in homogeneous material for the restricted substances, and 0.01% for cadmium. A product weighing hundreds of grams can be non-compliant because a plating layer weighing a fraction of a gram is over the limit in itself.
Which is why an averaged, product-level report is not evidence. It is arithmetic performed on the wrong denominator, and it is one of the commonest documents a Chinese supplier will send when asked for "the RoHS report".
What a useful report looks like: a breakdown by part or material, showing which materials were tested, what was found in each, and against which limit. Ask which parts were sampled and how they were selected, because a report covering the housing and the screws while omitting the solder, the plating and the wire insulation has tested the easy parts.
And exemptions exist. Certain applications of restricted substances are permitted for defined uses and periods. If a supplier is relying on one, it should be named and its scope checked against your product — an exemption for a different application is not an exemption for yours.
REACH is a different question
RoHS restricts specific substances in electrical and electronic equipment. REACH regulates chemicals far more broadly across the European Union, and most of it concerns substances and mixtures rather than finished articles.
The part that reaches an importer of finished goods is the candidate list of substances of very high concern. Where such a substance is present in an article above 0.1% by weight of the article, duties to communicate information down the supply chain are triggered — and separately, information about articles containing candidate-list substances above that threshold is expected to be provided to the EU database maintained for that purpose.
The list grows. Substances are added periodically, so a REACH declaration is a snapshot: it should name the version of the candidate list it was made against and the date it was made. This page publishes no count of substances on the list, because a count in a guide is wrong within months and a stale number is worse than none.
What to ask for. A statement per article that names the candidate list version and date, and — where a substance above the threshold is present — what it is, in which part, and what information is being passed on.
And note the different denominators, because this is where people get confused: RoHS is measured against the homogeneous material, REACH candidate-list communication against the weight of the article. Two thresholds that look similar and are not comparable.
What suppliers actually send, and what to do with it
A one-page "RoHS certificate" with a logo. Usually a declaration rather than test data, often covering "the product" rather than its materials, and sometimes carrying a laboratory name that did no testing on your model. It is a starting point for a conversation, not an answer.
A test report for a different model. Extremely common. Check the model on the report against the goods on your purchase order, and check the applicant against the company invoicing you.
A supplier declaration with no date and no reference. Ask for the version of the requirements and the candidate list it was made against, and the date. An undated compliance statement cannot be relied on later, which is exactly when it will be needed.
What to require instead, in the specification: RoHS compliance stated at material level with supporting test data covering the parts that actually carry risk — solders, platings, wire insulation, flexible plastics — and a REACH statement naming the candidate list version and date, both to be refreshed when the design or the supply chain changes.
And require notification of material changes. The commonest way a compliant product becomes non-compliant is a component substitution nobody told you about — the same clause that protects your battery documentation protects this.
Who carries the obligation, and where it is enforced
The obligation follows the party placing the product on the market. Selling under your own name generally makes you the manufacturer for these purposes, so the technical documentation supporting the RoHS position is yours to hold and to produce.
Enforcement is by market surveillance, and it is real. Authorities test products taken from the market, and the test is done at material level — which is exactly the level an averaged supplier report does not address.
Marketplaces ask too, increasingly and with short deadlines. A declaration you cannot produce within a few days is, commercially, a declaration you do not have.
The practical minimum: know which materials in your product carry risk, hold test data for those, hold a dated REACH statement, and have a clause that makes a component change a notification rather than a surprise. That is a short list, it is achievable at quotation, and it is far cheaper than the alternative.
Questions people actually ask
What are the RoHS limits?
0.1% by weight in homogeneous material for the restricted substances, and 0.01% for cadmium. The critical part is "in homogeneous material": the limit applies to each material that cannot be mechanically separated into different materials — a solder joint, a plating layer, one wire's insulation — not to the product as a whole.
Why is a product-level RoHS report not enough?
Because it is arithmetic on the wrong denominator. A device could average comfortably under the limit and still be non-compliant because one small material within it is over. Ask for a breakdown by part or material showing which materials were tested, what was found in each and against which limit.
What is a homogeneous material?
One that cannot be mechanically separated into different materials — by unscrewing, cutting, crushing, grinding or abrading. A cable is not homogeneous; the copper, the insulation and the sheath each are. A plated contact is not; the base metal and each plating layer are.
Is REACH the same as RoHS?
No. RoHS restricts named substances in electrical and electronic equipment at material level. REACH is a much broader EU chemicals regime, and the part reaching an importer of finished goods is the candidate list of substances of very high concern, with communication duties above 0.1% by weight of the article. Note the different denominators — material for RoHS, article for REACH.
Why should a REACH declaration have a date?
Because the candidate list is added to over time, so a declaration is a snapshot. It should name the version of the list it was made against and the date it was made — an undated compliance statement cannot be relied on later, which is exactly when it will be needed.
What should I put in the specification?
RoHS compliance stated at material level with test data covering the parts that carry real risk — solders, platings, wire insulation, flexible plastics — a REACH statement naming the candidate list version and date, and a clause requiring notification of any component or material change. That last clause is what stops a quiet substitution turning a compliant product into a non-compliant one.