RoHS limited 10 substances. But the question that takes businesses the most time is not “how much is the limit” but rather “calculated on what”. RoHS answer is: calculated above homogeneous material — not on the whole product.
This article goes through each substance: the limit, how to convert, where the limit is most likely to be exceeded, and common misconceptions that cause test results to be misinterpreted.
1. Table of 10 restricted substances
| # | Quality | CAS | Maximum limit | Common place |
|---|---|---|---|---|
| 1 | Lead (Pb) | 7439-92-1 | 0.1 % | Welds, brass alloys, easily machined steel, stable PVC, glass, ceramic of components |
| 2 | Mercury (Hg) | 7439-97-6 | 0.1 % | Tilt switches, relays, fluorescent lights (now rarely seen) |
| 3 | Cadmium (Cd) | 7440-43-9 | 0.01 % | Electroplating layer, contacts, brass alloy, old battery |
| 4 | Hexavalent chromium — Cr(VI) | 18540-29-9 (ion) | 0.1 % | Chromium passivation layer on galvanized steel parts, paint, and ink |
| 5 | Polybrominated biphenyls (PBB) | Substance group | 0.1 % | Brominated flame retardants in plastics (mostly eliminated) |
| 6 | Polybrominated diphenyl ethers (PBDE) | 1163-19-5 (decaBDE) | 0.1 % | Brominated flame retardants; Focusing on recycled plastic ABS/HIPS |
| 7 | DEHP — bis(2-ethylhexyl) phthalate | 117-81-7 | 0.1 % | PVC cable, soft plastic cover, glue, printing ink |
| 8 | BBP — benzyl butyl phthalate | 85-68-7 | 0.1 % | Soft PVC plastic, glue, ink |
| 9 | DBP — dibutyl phthalate | 84-74-2 | 0.1 % | Glue, printing ink, plasticizer in PVC |
| 10 | DIBP — diisobutyl phthalate | 84-69-5 | 0.1 % | DBP’s “brother” plasticizer, often included in the same material |
One exception to remember: cadmium has a limit 0.01 % — exactly 10 times tighter than the other substances. This is the reason why cadmium is the substance that causes the most “dead” shipments in the plating and alloy industry.
2. The limit is calculated on “homogeneous materials”, not on products
This is the easiest point to misunderstand. RoHS no requires “the average of the whole product is less than 0.1%”. It requires: all materials are homogeneous Product components must all be below the limit.
Direct consequence: can a product weighing 2 kg meet RoHS despite containing a 5 g screw that exceeds the limit? No. Just one homogenous material exceeds the limit, the product has failed — no matter how small the volume of material.
| How to calculate | Results | True or false according to RoHS |
|---|---|---|
| Average across all products | Can output 0.02 % → “pass” | Wrong — RoHS does not use this method |
| On each material uniformly | Plating layer has 0.08% Cd → “failed” | Yes — this is how RoHS regulates it |
Therefore, the disassembly step (disassemble to a homogeneous material) determines the correctness of the entire result. If the disassembly is wrong — for example, taking the entire connection port assembly together — then even if the test room does it very accurately, the results will still be legally meaningless.
3. Convert between %, ppm and mg/kg
The three ways to write below are same value:
| Threshold | Write in % | Write in ppm / mg/kg |
|---|---|---|
| The remaining nine substances | 0.1 % | 1,000 ppm = 1,000 mg/kg |
| Cadmium | 0.01 % | 100 ppm = 100 mg/kg |
In practice, test reports are often presented in mg/kg, while contracts and declarations of conformity are often stated in %. When comparing, refer to the same units — this is a very common administrative error when reading quick reports.
4. Four phthalates: four “new” substances but have been available since 2015
PBB and PBDE are the six parent substances since 2003. Four phthalates (DEHP, BBP, DBP, DIBP) are added by Directive (EU) 2015/863, with application roadmap by product group:
| Product group | Time to start applying |
|---|---|
| Common electrical and electronic equipment | July 22, 2019 (some groups), July 22, 2021 (mostly) |
| Medical equipment, monitoring and control equipment | July 22, 2021 |
| In vitro diagnostic medical equipment | July 22, 2024 |
Of these four substances, DIBP has one practical characteristic: it is common Comes with DBP in the same PVC material. So if the DBP is reported to be close to the limit, check the DIBP of the same material — this is a common trap when screening just one substance.
5. What happens if the limit is exceeded?
| Situation | Consequences |
|---|---|
| A homogeneous material exceeds the limit, with no exemption | The product is not placed on the EU market — does not have a valid CE marking |
| Exceeded the limit but There are exemptions Correct item and on time | Allowed — but must be documented in technical records and declaration of conformity |
| Discovered after sale | Must handle: recall, notify supervisory agency — costs are often much greater than the cost of redesigning from scratch |
Important points: Exceeding the limit is not automatically a violation. A violation is “exceeding the limit and not subject to exemption”. So the first question when seeing a red result is not “how to replace the material” but “is this material included in any exemptions?”
6. Actual hot spots for each substance group
- Lead: welds (also used in high temperature welds), brass alloys in valves/connecting pipes, free-machining steel, PVC for stabilization. Most cases still rely on exemptions — and exemptions are what are renewing in 2026–2027.
- Cadmium: electroplating, electrical contacts, low-temperature solder alloys, doped brass. It is very difficult to handle because the 0.01% limit is close to the background level of many materials.
- Cr(VI): chromium passivation layer on galvanized steel parts. XRF equipment that reports “Cr” only indicates total chromium, Cannot distinguish Cr(III) and Cr(VI) — the above-limit results from XRF are not enough to make a conclusion.
- PBB and PBDE: focus on recycled plastic. ABS/HIPS plastic materials recycled from old equipment are where the most organic bromine residues are.
- Four phthalates: PVC cable, soft plastic cover, glue, printing ink. In many cases, phthalates are cross-contaminated from belts, packaging, or from the conveyor belts and gloves used in production.
7. Five common misconceptions
- “On average, all products below the limit are satisfactory.” Incorrect — RoHS calculated based on homogeneous materials.
- “Small amounts of materials don’t count.” Wrong — one 3g screw exceeding the limit is enough to fail the product.
- “XRF pass is definitely pass.” Not really — XRF is a screening method; Inconclusive results require chemical testing, and XRF does not distinguish between chemotherapy types.
- “Exceeding the limit is a violation.” Not necessarily — if the exemption is on time and in the right section, it is valid.
- “RoHS only applies to goods exported to the EU.” No longer true — China already has a mandatory standard GB 26572-2025 with a list of substances almost identical to the EU, effective from August 1, 2027.
8. Frequently asked questions
What is meant by the pressure limit for “homogeneous material”?
The smallest level that can be separated mechanically — for example, plating, paint, individual welds, each type of plastic in a multi-material part. If further separation is not possible without damaging the material, it is a homogeneous material.
Cadmium 0.01% is how many ppm?
100 ppm, equivalent to 100 mg/kg. The remaining nine substances are at the limit of 1,000 ppm (0.1 %).
In the same part there are many materials, how to take samples?
Disassemble each homogeneous material and test it separately. Do not grind together. Details of the dissection procedure will be found in our separate article on sample dissection according to IEC 62321-2.
If XRF reports a result below the limit, do we need to test further?
Usually not, if the XRF is well calibrated and the results are clearly below the limit (not close to the limit). If results are close to the limit or if the sample background is suspected to be complex, it should be confirmed by chemical methods.
Can a product that meets all 10 substances be labeled “RoHS compliant”?
Recorded in an honest and authoritative manner, but note: “RoHS compliant” is a manufacturer’s declaration, not a certification issued by an organization. Misrepresentation — for example, saying “certified” when only a test report is available — could be considered misleading.
9. Conclusion
RoHS limits 10 substances with a limit of 0.1% — only cadmium 0.01% — and Apply to each material uniformly. Three things need to be understood: right limit, right unit, right way of dissection. If one of the three is wrong, the test results — no matter how accurate the test lab is — will not protect the business from market surveillance agencies.
References
- Directive 2011/65/EU (RoHS 2), Annex II — list of restricted substances
- Directive (EU) 2015/863 amends Annex II, adding four phthalates
- IEC 62321 — set of methods for the determination of substances in electrical and electronic products
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Disclaimer
This article is an interpretive content compiled by us; not legal advice. CAS numbers and limits are given for reference and should be compared with the text of Annex II of Directive 2011/65/EU (consolidated version).
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