Most companies working with nanoclay understand the first layer of compliance: the substance has to be on the relevant chemical inventory. Bentonite is. Montmorillonite is. That box is usually ticked before anyone thinks hard about it.
The second layer is the one that catches people. A growing set of nano-specific obligations sits on top of ordinary chemical law, and they are triggered not by what the substance is but by what form it is in. The uncomfortable part is that “nano enough to trigger reporting” has no single definition. It has at least four, and they don’t agree.
Why there is no single definition
Start with the fact that produces most of the confusion.
The European Commission’s Recommendation on the definition of nanomaterial (2011/696/EU, updated in June 2022) sets the widely cited benchmark: a material qualifies if 50% or more of the particles in the number-based size distribution have at least one external dimension between 1 and 100 nm. Aggregates and agglomerates count.
Now hold that next to the EU Cosmetics Regulation. Article 2(1)(k) of Regulation (EC) No 1223/2009 defines a nanomaterial as an insoluble or biopersistent and intentionally manufactured material with one or more external dimensions, or an internal structure, on the 1–100 nm scale. Notice what is missing: there is no 50% threshold. The cosmetics definition is narrower in some respects (it requires intentional manufacture and biopersistence) and broader in others (no numerical cutoff at all).
The same product can therefore be a nanomaterial for one EU regime and not for another. This is not a drafting accident that will be tidied up shortly; these definitions have coexisted for over a decade.
For nanoclay specifically, the number-based criterion is treacherous. An individual montmorillonite platelet is roughly 1 nm thick — comfortably nano in one dimension. But commercial nanoclay powder is not individual platelets; it is stacks and agglomerates, and how you count them determines the answer. Two labs measuring the same drum by different methods can land on different sides of the 50% line. This is exactly why particle size distribution data, and the method used to obtain it, has become a commercially significant document rather than a technical footnote.
European Union: the deepest architecture
REACH nanoforms. Since Commission Regulation (EU) 2018/1881 took effect on 1 January 2020, companies manufacturing or importing a substance in nanoform at 1 tonne or more per year must provide nanoform-specific information in the registration dossier — characterization, and where relevant, nano-specific fate and toxicology. The nanoform is not covered by the bulk registration; it needs its own data.
Cosmetics. Two obligations, both under Regulation 1223/2009. The Responsible Person must notify the Commission through the CPNP six months before placing a nanomaterial-containing product on the market (Article 16(3)), with substance identity, full physicochemical characterization, estimated annual quantity, toxicological profile, and foreseeable exposure. Separately, Article 19(1)(g) requires the ingredient list to name the substance followed by “(nano)” in brackets. The lowercase form matters; enforcement authorities have flagged variants.
Note the trap: authorization of a substance in an annex does not automatically cover its nano form unless the annex says so.
National nano registers. Because the EU never adopted a bloc-wide nano register, individual member states built their own, and they bind you independently of REACH.
- France (R-Nano). Under Decree No. 2012-232, manufacturers, importers, and distributors of at least 100 grams per year of a substance in nanoparticulate state must file an annual declaration with ANSES. Note the threshold: one hundred grams. This is four orders of magnitude below the REACH tonnage trigger, and it catches R&D-scale and pilot-scale activity that REACH never touches. Declarations are due annually, and suppliers must pass their declaration number down the chain to French customers.
- Belgium. The Royal Decree of 27 May 2014 requires registration for substances in nanoparticulate form placed on the Belgian market from 1 January 2016, and for mixtures containing them from 1 January 2017, at the same 100 g/year threshold. Data must be updated between 1 January and 31 March each year.
- Denmark, Sweden, Norway. Denmark operates a standalone nano register for mixtures and articles. Sweden and Norway fold nanomaterial reporting into existing product registers, generally at higher thresholds.
The practical consequence: a company can be fully REACH-compliant and still be in breach in France or Belgium, because 100 grams of pilot material crossed a border.
United States: the “unique and novel” filter
EPA’s rule under TSCA section 8(a) (40 CFR 704.20, effective 14 August 2017) works on a logic that is genuinely different from Europe’s, and understanding the difference will save you unnecessary filings.
A reportable chemical substance must meet three conditions cumulatively: it is a solid at 25 °C and standard pressure; it is manufactured or processed in a form where particles — including aggregates and agglomerates — fall in the 1–100 nm range in at least one dimension; and it is manufactured or processed in that form specifically because it exhibits unique and novel properties that arise from the size.
That third condition is the whole ballgame. EPA defines unique and novel properties as size-dependent properties that differ from other forms of the same substance and are a reason the substance is made in that form. Size alone does not trigger reporting. A substance that happens to contain nanoscale particles incidentally is not caught; a substance engineered to be nanoscale because nanoscale performs differently is.
For nanoclay this is a real question rather than a formality. If you are selling exfoliated nanoclay into a nanocomposite application precisely because the platelet aspect ratio delivers barrier and mechanical properties the bulk mineral cannot, the “unique and novel” criterion looks satisfied. If you are selling bentonite as a bulk rheology modifier and the nanoscale fraction is incidental to why anyone buys it, the argument is much weaker.
Additional carve-outs that matter:
- Forms containing less than 1% by weight of particles in the 1–100 nm range are outside the rule.
- Small manufacturers and processors — defined for this rule as total annual sales, combined with any parent company, below $11 million — are exempt.
- The R&D exemption at 40 CFR 704.5 applies: small quantities solely for research and development are not caught.
- Substances not on the TSCA Inventory at the time reporting would be required are outside this rule — but that means a section 5 new chemical notification instead, which is a heavier obligation, not a lighter one.
Beyond the one-time reporting for substances already in commerce, anyone intending to manufacture or process a new discrete form of a reportable substance must notify EPA 135 days before commencing. If the intent forms with less than 135 days’ notice, the filing is due within 30 days of forming that intent.
Also worth knowing: TSCA does not reach substances manufactured for use as pesticides, food, food additives, drugs, cosmetics, or devices. Those sit under FDA or FIFRA frameworks instead. The jurisdictional line, not the material, decides which rulebook applies.
Asia-Pacific
China. The Ministry of Ecology and Environment’s chemical management framework requires new substance notification for substances not on the existing inventory. Conventional clays are generally listed. Novel surface-modified nanoclays with new modifiers can require separate notification.
Japan, South Korea, Australia. Japan’s CSCL, Korea’s K-REACH, and Australia’s AICS all require inventory listing before commercial manufacture or import. The base minerals are generally listed. The compliance risk sits with organoclays bearing modifiers that are themselves new substances — the surfactant, not the clay, is what triggers the filing.
The operational takeaways
Get particle size distribution data with the method stated. Number-based distribution, not just a D50. This single document determines whether you are inside or outside several definitions, and “the supplier said it’s not nano” is not a defensible position under regulatory scrutiny.
Map your volumes against the lowest threshold, not the highest. REACH’s 1-tonne trigger is comfortable; R-Nano’s 100-gram trigger is not. If you ship any quantity into France or Belgium, the low threshold is the one that governs.
For the US, document your reasoning on “unique and novel.” If you conclude the rule does not apply because the nanoscale character is incidental to the product’s purpose, write down why, and keep it. That reasoning is the compliance artifact.
Ask suppliers for their registration and declaration numbers. French suppliers must pass R-Nano declaration numbers downstream. Reputable suppliers maintain regulatory files and will provide REACH registration numbers, TSCA status, and food-contact authorizations on request. Inability to produce them tells you something.
Watch this space. Nano-specific regulation has been the fastest-moving corner of chemical law for a decade, and there is no sign of it settling. Anything in this article should be verified against current sources before you rely on it.
This article is general information, not legal advice. Regulatory obligations depend on your specific substance, form, volume, use, and jurisdiction, and the rules change. Confirm current requirements with qualified regulatory counsel before placing product on any market.