Reference

PCN & UFI glossary

38 terms you will meet in poison centre notification work, defined the way they are used in practice. Each entry has a stable anchor — link to any term directly.

Annex VIII (to CLP): The annex of the CLP Regulation that created the harmonised poison centre notification: what information must be submitted, in what format, by whom, and when. Added by Regulation (EU) 2017/542; the operative text today reflects the 2020/1677 amendment.
Appointed body: The national organisation each member state designates under CLP Article 45 to receive information on hazardous mixtures for emergency health response — the destination of your PCN in that country. Some states appoint their poison centre directly, others a public-health agency.
Article 45 (CLP): The CLP article obliging importers and downstream users to submit information on hazardous mixtures to appointed bodies, and the legal hook Annex VIII hangs on.
BR rules (business rules): The automated validation checks ECHA's submission system runs on every PCN dossier. A failed BR rule blocks the submission; the failure code tells you which field to fix.
Checksum (UFI): The self-verification built into every UFI: the code's characters must satisfy a mod-31 arithmetic rule, so a single mistyped character makes the whole code invalid rather than pointing at the wrong formulation.
CLP Regulation: Regulation (EC) No 1272/2008 on classification, labelling and packaging of substances and mixtures — the EU's implementation of the UN GHS system, and the parent regulation of both Article 45 and Annex VIII.
Company key: A numeric identifier ECHA's UFI Generator issues to companies that cannot or prefer not to use a VAT number as the seed for UFI generation. Plays the same role as the VAT number in the algorithm.
Components of major concern: Ingredients that drive the health hazard of a mixture and must therefore be declared with tighter concentration precision under Annex VIII Part B — narrower permitted ranges than for other components.
Concentration ranges: Annex VIII lets you declare component concentrations in bands rather than exact values. The permitted width of each band depends on the component's hazard: the more hazardous, the narrower the allowed range.
Consumer use: A use type in the PCN: the mixture reaches the general public. Consumer-use notifications carry the fullest information requirements and have been mandatory for new placements since 1 January 2021.
Distributor: An actor who stores and sells a mixture without changing it. Historically outside the PCN duty, but the 2024/2865 CLP revision brings distributors into Article 45 in defined cases, applying from 1 January 2027.
Downstream user: A company that uses or incorporates a substance or mixture in its own industrial or professional activity — including formulators who blend mixtures. One of the two primary PCN duty holders, alongside importers.
Duty holder: The legal entity responsible for submitting the PCN: the importer or downstream user placing the hazardous mixture on a member state's market. Liability for the notification's accuracy stays with the duty holder regardless of who prepares it.
ECHA: The European Chemicals Agency, based in Helsinki. For PCN purposes it operates the central Submission portal, the PCN format, the UFI Generator, and the EuPCS — and relays dossiers to the national appointed bodies.
ECHA Submission portal: ECHA's central web portal for submitting PCN dossiers to one or more member states at once. Free to use; national fees, where they exist, are charged separately by the member state.
Enforcement Forum: ECHA's network of national enforcement authorities. It ran the 2025 pilot project on PCN enforcement (reported February 2026) and coordinates REF-14, the 2026 inspection project covering mixtures in consumer products.
EuPCS: The European Product Categorisation System — a five-level tree of roughly 250 categories describing a mixture's intended use. Every PCN must assign exactly one EuPCS category to the product.
Formulation number: A whole number between 0 and 268,435,455 that a company assigns to one specific composition, and the second input (with the VAT number or company key) to the UFI algorithm. The numbering scheme is yours to choose; the code, once generated, hides it.
Group submission: A single PCN covering several mixtures that share the same classification and composition apart from defined permitted differences (e.g. perfume variants within limits). One dossier, multiple products.
Health hazard: A CLP hazard class describing effects on people — acute toxicity, skin corrosion, sensitisation, and so on. Classification for any health hazard (with narrow exemptions) puts a mixture in PCN scope.
.i6z dossier: The file format of a PCN submission: a zipped IUCLID archive containing the structured mixture data. Built by IUCLID Cloud, IUCLID 6, or software that assembles it directly — then uploaded or submitted system-to-system.
Importer: The company that brings a mixture from outside the EU/EEA onto the EU/EEA market. Importers are primary PCN duty holders; buying from an EU supplier instead makes you a downstream user or distributor.
Industrial use: A use type in the PCN: the mixture is used only at industrial sites. Industrial-use mixtures may qualify for a limited submission with reduced information, provided rapid access to full data is available on request.
IUCLID: The OECD/ECHA software and data format for chemical dossiers. The PCN format is defined as an IUCLID data structure, which is why PCN dossiers are .i6z files regardless of which tool builds them.
Limited submission: The reduced-information PCN allowed for industrial-use-only mixtures: less compositional detail up front, in exchange for guaranteeing 24/7 rapid access to the full composition if a poison centre requests it.
Mixture in mixture (MiM): A mixture used as a component of another mixture. When the supplier won't disclose the MiM's full composition, Annex VIII lets you reference it by the supplier's UFI, or by its identifiers plus the supplier's contact details.
PCN (poison centre notification): The harmonised submission of a hazardous mixture's full composition, toxicology, product category, and packaging information to member state appointed bodies via the Annex VIII format — the core legal duty this glossary orbits.
PCN format: The structured XML data model every notification must follow, versioned by ECHA roughly annually alongside IUCLID releases. Version 8 has been current since April 2026; version 7 (May 2025) preceded it.
Physical hazard: A CLP hazard class describing dangerous physical behaviour — flammability, explosivity, oxidising properties. Classification for a physical hazard triggers PCN scope, with exemptions for gases under pressure and certain explosives.
Poison centre: The medical service clinicians and the public call in poisoning emergencies. Poison centres query the notified-mixture database — by UFI when available — to identify what a patient was exposed to.
Professional use: A use type in the PCN: the mixture is used by professionals outside industrial sites (cleaners, decorators, workshops). Information requirements match consumer use since the 2020/1677 amendment aligned them.
QLT rules (quality rules): ECHA's soft validation checks: unlike BR rules they don't block a submission, but they flag quality issues in the dossier that appointed bodies may follow up on.
REF-14: The Enforcement Forum's coordinated inspection project running through 2026, checking classification, labelling, packaging, PCN notifications and SDSs of hazardous mixtures in consumer products. Reports in 2027. Distinct from the 2025 pilot enforcement project.
S2S (system-to-system): ECHA's machine-to-machine submission channel: software authenticates with ECHA-issued keys and submits PCN dossiers directly, without a human uploading files to the portal. The channel Ufi Number uses.
Standard formula: Pre-agreed compositions listed in Annex VIII (cement, gypsum, ready-mixed concrete) that may be notified against the published standard composition instead of the manufacturer's exact recipe.
Submission number: The identifier ECHA's system assigns to each accepted submission. It is your proof of notification — the number an inspector or customer asks for, and the reference for later updates.
UFI (Unique Formula Identifier): The 16-character code printed on hazardous mixture labels that links the product to its notified composition. Generated from a VAT number (or company key) plus a formulation number using ECHA's published algorithm.
Use type: The PCN's declaration of who uses the mixture: consumer, professional, industrial, or combinations. Determines the information requirements and, for industrial-only mixtures, eligibility for limited submission.

Want the concepts in context rather than alphabetically? Start with the pillar guides: what a UFI is, what a poison centre notification is, and Annex VIII explained.