EU REACH Compliance Checklist for Propylene Oxide Imports: SVHC, Annex XVII & Y-Codes

Propylene oxide (PO; CAS 75-56-9; EC 200-879-2; CLP Index 603-055-00-4) is subject to a layered regulatory sequence at EU import because the harmonised classification combines flammable liquid, acute oral/dermal/inhalation toxicity, skin irritation, serious eye irritation, specific target organ toxicity from single exposure, carcinogenicity and germ cell mutagenicity. The substance is a phase-in EINECS compound, not a no-longer polymer, and the imported monomer is a monoconstituent grade. An import consignment exceeding 1 tonne/year falls within REACH Article 6(1) unless a registration is already held by the importer or an only representative has been appointed under Article 8. The same tonnage trigger creates a CLP Article 40 notification duty to the Classification and Labelling Inventory unless the same classification has been submitted through a REACH registration dossier. Because propylene oxide monomer is a well-defined monoconstituent, the customs identity record must follow the CUS route rather than a Y-code route; PO-derived alkoxylation streams with undefined or variable composition may carry an ECICS Y-code. The TARIC code CN 2910 20 00 applies to methyloxirane in the monomer grade.

What Does the Candidate List Entry Impose on Bulk PO Importers?

The ECHA Candidate List includes propylene oxide as a substance meeting the Article 57(a) criteria for carcinogenicity and germ cell mutagenicity. The listing does not prohibit bulk import. It activates Article 33 communication for articles containing PO above 0.1% w/w and the Waste Framework Directive SCIP notification duty for such articles. For bulk importers, the primary operational impact is extended safety data sheet management under REACH Article 31(3), because a mixture containing an SVHC at or above 0.1% w/w requires SDS provision on request even if the mixture is not classified as hazardous. The 0.1% w/w threshold is a concentration limit for articles and mixtures, not a customs release threshold. A bulk PO import at high purity therefore does not require an Article 33 communication at the import gate, but downstream formulators using PO to produce articles or mixtures with residual monomer above 0.1% w/w must track the communication duty.

An importer relying on an only representative registration must confirm that the registered tonnage band covers the imported volume and that the registered substance identity matches the imported grade. Registration dossiers for propylene oxide include use descriptors for closed-system consumption in polyether polyol plants, propylene glycol manufacture and controlled polymerisation. The safety data sheet must carry the registration number in Section 1.1, and the exposure scenario must be consistent with the site process category and environmental release category. A mismatch between the registered exposure scenario and the actual industrial use is a REACH Title V non-conformity. Importers using the substance as a monomer in a polymerisation unit must retain a use map linking the purchase order to the registration number and the operational conditions of the reactor, including temperature setpoints, relief pressure and residual oxide monitoring. Propylene oxide is not included in REACH Annex XIV; therefore no authorisation application or Annex XIV sunset date applies to current imports. If the substance is subsequently prioritised for Annex XIV, importers would need to separate uses exempted from authorisation from those requiring an application and update their REACH-IT submissions accordingly.

Annex XVII Entry 28 and 29 Boundaries for Consumer Supply

Annex XVII to REACH applies restrictions that are distinct from authorisation. Entries 28 and 29 restrict substances classified as carcinogen category 1A/1B or germ cell mutagen category 1A/1B in substances or mixtures supplied to the general public. The CLP generic concentration limit for category 1B carcinogenicity and mutagenicity is 0.1% w/w; propylene oxide has no Annex VI-specific concentration limit overriding that value. The practical consequence is that a PO-containing preparation with monomer at or above 0.1% w/w cannot be placed on the market for general consumer use. Industrial and professional use is outside the Entry 28 and 29 restriction, but the supplier must control that the product is not sold through retail channels. The classification H350 and H340 triggers hazard communication, but the restriction does not ban professional use. Annex XVII Entry 3 may additionally apply to PO as a flammable and toxic liquid when used in decorative objects, games or similar consumer articles; a bulk industrial import of the monomer does not fall under that entry unless the consignment itself is a consumer product or a preparation for such use.

Warehouse operators and distributors must not repackage PO-based preparations into retail-sized containers if the PO content is at or above 0.1% w/w. The restriction does not bind closed-loop tank container transfer into a reactor feed system. In toll manufacturing arrangements, the contract must specify whether the EU legal entity receiving the imported PO is the importer or a downstream user; that status changes the registration duty. A bulk PO monomer import supplied to an industrial polyether polyol plant is outside Entries 28 and 29, but a consumer preparation containing residual PO at or above the threshold would be non-compliant. A downstream use declaration mapping the first non-EU customer and the final application sector must be obtained and retained for compliance auditing.

Separate from the safety data sheet layer, the customs chemical identity record must be checked against the European Customs Inventory of Chemical Substances. ECICS assigns CUS numbers to well-defined substances and Y-codes to substances of unknown or variable composition, complex reaction products or biological materials (UVCB) and to certain group entries that cannot be represented by CAS or EC identification. Propylene oxide monomer is a defined substance with CAS 75-56-9 and EC 200-879-2 and must be declared under the CUS entry corresponding to methyloxirane; a Y-code must not be used for the monoconstituent import. However, PO is frequently moved as an intermediate in mixed C3 oxide streams, recovered epoxide fractions or alkoxylation feedstocks with variable composition. In such cases the consignment may be lawfully identified by a Y-code if the material is not a single well-defined substance. The importer must record in the technical dossier whether the product is monoconstituent, multi-constituent or UVCB, because that determination changes the REACH substance identity profile and the customs declaration. A Y-code entered on the Single Administrative Document without supporting UVCB composition data is a non-conformity. Where a PO monomer consignment contains a low-level stabiliser, the main component remains identified by CAS 75-56-9 and CN 2910 20 00; the stabiliser does not convert the defined substance into a Y-coded UVCB.

The consequence of using an incorrect Y-code is not limited to customs penalties. REACH registration obligations are substance-specific. If a defined PO monomer is declared as a UVCB Y-code, the ECHA registration number for the monoconstituent may not correspond to the declared customs identity, creating a compliance gap under Article 6(1). Reverse cases are equally problematic: a UVCB stream declared as CAS 75-56-9 assumes that the substance is a defined monoconstituent, but the REACH registration dossier for the UVCB may show a different composition and hazard set. The importer must maintain an identity mapping table linking the purchase specification, bill of lading, analytical certificate, ECICS code, TARIC code and registration number. For articles, the 0.1% w/w threshold is calculated on the article mass as defined in ECHA guidance. When PO is used as a comonomer in a block copolymer, the residual unreacted monomer concentration in the final article is the relevant value for Article 33, not the reactor feed concentration. Analytical verification of residual monomer by gas chromatography with flame ionisation detection and a reporting limit below 0.1% w/w is required to confirm article-level compliance.

When a PO Alkoxylation Stream Is Declared Under an ECICS Y-Code

The Y-code is an ECICS identifier for a UVCB or group entry. It is not a substitute for a REACH registration number. An importer must not select a Y-code solely to avoid disclosing impurities or to simplify the customs declaration. If a PO-containing alkoxylation stream is declared under a Y-code, the accompanying safety data sheet must describe the UVCB hazards, not only the monomer hazards. Where the stream contains propylene oxide at or above 0.1% w/w, the CLP classification and SDS obligations are driven by the monomer as a hazardous constituent, and the Article 33/SCIP communication duty can attach to articles produced from that stream. The customs declaration must align with the registration status of the UVCB. If the UVCB is not registered under REACH and import exceeds 1 tonne/year, the importer must submit a registration or rely on an only representative registration that explicitly covers the UVCB identity. For alkoxylation plants, the reactor-grade feed may be a multi-constituent material rather than a monoconstituent monomer; the ECICS Y-code and the REACH substance identity profile must be reconciled before release for free circulation.

The ECICS Y-code check is particularly relevant for PO streams recovered from propylene oxide/styrene monomer coproduct or chlorohydrin process tail fractions. These materials may be UVCB because the constituent profile varies with distillation cut, reflux ratio and feed grade. Under such conditions, the analytical dossier should include gas chromatography data for the main C3 components, water content, aldehydes and residual chlorinated by-products. If the gas chromatography data indicate a dominant PO concentration but the matrix is variable, the customs declaration may still require a Y-code if ECICS has no CUS entry matching the exact UVCB composition. The importer must document why the product is not identified by CAS 75-56-9 as a monoconstituent. A declaration of a defined monomer using a Y-code is rejected by customs on the ground that the ECICS identity is not compatible with the TARIC measure.

Documentary Evidence and Border Control Sequence

A border inspection for propylene oxide monomer typically verifies the TARIC measure page, the ECICS CUS code, the SDS, the REACH registration number and the transport classification. The transport code UN 1280, Class 3, Packing Group I applies to the flammable liquid. The import declaration must include the exact chemical name methyloxirane, the CN code 2910 20 00, and the relevant ECICS code. If the consignment is a UVCB stream, the Y-code must be supported by composition data and a registration number for the UVCB. The importer must have the CLP label elements available for inspection: signal word Danger, hazard statements H224, H350, H340, H301, H311, H331, H315, H319, H335. Because the REACH restriction and SVHC duties are threshold-based, the border authority may not perform a quantitative verification of the 0.1% w/w threshold at the gate; the obligation remains with the importer to maintain records demonstrating the actual monomer concentration and the end-use category. The Y-code verification then becomes a customs and REACH identity consistency check rather than an independent safety assessment.