Import documentation for propylene oxide (PO; EC 200-879-2; CAS 75-56-9) now requires a clear separation between the Annex XIV authorisation status, the isolated-intermediate exemption under REACH, and the Seveso III establishment classification that follows from stored inventory. The substance is harmonised under Regulation (EC) No 1272/2008 Annex VI with Flam. Liq. 1 H224, Carc. 1B H350, Muta. 1B H340, Acute Tox. 4 H332, Skin Irrit. 2 H315, Eye Irrit. 2 H319 and STOT SE 3 H335. The carcinogenicity and germ cell mutagenicity classifications are the Annex XIV triggers under Articles 57(a) and 57(b) of REACH. Consequently, import of propylene oxide as a substance or in a mixture for non-intermediate uses entered the authorisation regime with a latest application date of 4 September 2024 and a sunset date of 4 March 2026. From 5 March 2026, placing on the market without a granted authorisation is prohibited unless the operation remains within the strict intermediate-use exemption or another legally valid exemption applies.

What Changes After the 4 March 2026 Sunset Date?

After 4 March 2026, a non-exempt EU importer may no longer place propylene oxide on the market for a non-intermediate use unless the European Commission has granted an authorisation for that specific use. The authorisation is use-specific, not substance-specific. Identical propylene oxide volumes may therefore require separate authorisations for polyether polyol manufacture, propylene glycol production, or solvent use. An application under Article 62 of REACH must include a chemical safety report, an analysis of alternatives, and a socio-economic analysis if the risk cannot be demonstrated as adequately controlled. The Committee for Risk Assessment evaluates the risk portion; the Committee for Socio-Economic Analysis evaluates the socio-economic elements. A complete application filed before the latest application date of 4 September 2024 can, under standard REACH authorisation procedure, permit continued supply beyond the sunset date pending the Commission decision. Without that filing, the non-exempt supply window closed on 4 March 2026.

Downstream users are inside the same timeline even when they do not import directly. If a downstream user relies on an authorisation granted to a supplier, the downstream user must notify ECHA within 3 months of first supply in accordance with Article 66(1) of REACH. Where the downstream use is not covered by the upstream authorisation, the downstream user becomes an applicant and must demonstrate its own risk-control or socio-economic justification. A missed latest application date cannot be cured by a customs declaration or by changing the commercial name of the product; the Annex XIV obligation follows the EC number and the use.

If Propylene Oxide Is Imported as a Transported Isolated Intermediate

For monomer-grade propylene oxide imported for immediate conversion into propylene glycol or polyether polyol within a closed reactor system, the authorisation title may not apply. Article 2(8)(b) of REACH removes transported isolated intermediates from the Title VII authorisation requirements when the substance is rigorously contained by technical means throughout its lifecycle and the receiving site applies strict control under Article 18. The word “isolated” is not a minor descriptor: any drumming-out, repackaging, distribution to a third-party formulator, or use in preparation of a downstream mixture breaks the intermediate chain and triggers the Annex XIV authorisation obligation. Importers must maintain batch-level mass balance records showing that the entire received propylene oxide quantity is consumed by reaction, not placed on the market as a substance or a mixture. Where the same vessel commingles exempt intermediate-use material and non-exempt material, the non-exempt portion requires an authorisation number before the sunset date is reached.

Only legal entities established in the EU can submit a REACH authorisation application. Non-EU exporters cannot file directly. The EU importer, downstream user, or an only representative appointed under Article 8 of REACH carries the application duty. In propylene oxide supply chains where a non-EU producer sells to multiple EU customers under one only representative, the authorisation application must identify the uses applied for and the tonnage band. If different importers have different uses, a joint application under Article 62 is possible, but each use is evaluated separately. Submission is made through REACH-IT using IUCLID data, and fees are set under Commission Regulation (EC) No 340/2008 as amended.

Seveso III Named-Substance Thresholds and Transfer Equipment

Annex I Part 2 of Directive 2012/18/EU lists propylene oxide as a named substance with a lower-tier qualifying quantity of 5 t and an upper-tier qualifying quantity of 20 t. The named entry takes precedence over generic flammable-liquid categories. An establishment storing 20 t or more at any one time is upper-tier and must prepare a safety report, implement a major accident prevention policy, develop an internal emergency plan, supply information to the competent authority for external emergency planning, and comply with land-use planning provisions. Establishments between 5 t and 20 t are lower-tier; the main obligations are notification, a major accident prevention policy, and proportionate risk control. Given propylene oxide density of approximately 0.83 g/cm³ at 20 °C, 20 t corresponds to roughly 24,100 L of liquid volume. A single 24,000 L tank container filled to 95% contains approximately 18.9 t, which is below the upper-tier threshold but above lower-tier; two such tanks in the same establishment exceed the upper-tier threshold. This explains why even a modest import receiving bay with two 20-foot tank containers can shift the site into Seveso upper-tier status.

At the receiving terminal, propylene oxide is normally handled as a liquefied flammable liquid with a boiling point near 34 °C. Closed-loop unloading with vapour return, nitrogen blanketing, and pressure-relief devices sized to ISO 4126-1 or EN ISO 4126-1 are standard. Transfer lines should be dedicated, and gasket selection must follow supplier compatibility data for low-boiling epoxides; elastomer swelling in vapour spaces is a recognised maintenance issue. The substance is incompatible with amine-based additives and strong acids, and contamination with such residues can initiate exothermic polymerisation. Inventory in a storage tank is the relevant figure for Seveso classification, not the annual import tonnage. It is possible for an establishment to be Seveso upper-tier even when annual throughput is modest, because the qualifying quantity is based on maximum instantaneous presence.

Transport classification is equally direct: propylene oxide is carried under UN 1280, Class 3, Packing Group I. The low flash point and high vapour pressure require pressure-rated or refrigerated containment, and the import receiving line should be integrated with the site safety instrumented system rather than treated as a simple solvent transfer. For the EU importer, the documentary chain must therefore include the Annex XIV authorisation number or the isolated-intermediate exemption evidence, the Seveso notification status of the receiving establishment, and the tank-container or vessel certificate for the transport equipment. Missing any of these elements creates an enforcement exposure that cannot be resolved by the supplier’s non-EU documentation alone.