Name: UN 2421 — NITROGEN TRIOXIDE
Creator: FreightUtils
License: https://creativecommons.org/licenses/by/4.0/

Carriage prohibited by ADR (road)

ADR 2025 Table A lists UN 2421 (NITROGEN TRIOXIDE) as “CARRIAGE PROHIBITED” — it may not be carried by road under ADR. No packing group, transport category, or 1.1.3.6 small-load exemption applies: the entry is banned from carriage, not exempt from it.

UN 2421Class 2 — GasesCarriage prohibited

Packing Group: None; Carriage prohibited — see the verdict above
Classification Code: 2TOC
Tunnel Code: None meaning →; Carriage prohibited — see the verdict above
Transport Category: —; None — the entry may not be carried by road under ADR
Hazard ID No.: —; Kemler code
Limited Quantity: —; Carriage prohibited — see the verdict above
Excepted Quantity: —; Carriage prohibited — see the verdict above

ADR 2027 (accepted)

ADR 2027 was accepted: depositary notification C.N.395.2026 (9 October 2026) records no objection to the amendments proposed by C.N.252.2026. It applies from 1 January 2027, and ADR 2025 may still be applied until 30 June 2027 (1.6.1.1). (C.N.395.2026)

The ADR 2027 amendments (ECE/TRANS/WP.15/274, ECE/TRANS/WP.15/274/Add.1, ECE/TRANS/WP.15/274/Corr.1) make no change to this entry's Table A columns. Other parts of ADR 2027 may still affect its carriage.

ADR 2025 remains the edition FreightUtils serves and the one that applies until ADR 2027 takes effect on 1 January 2027; after that, ADR 2025 may still be applied until 30 June 2027 (1.6.1.1).

All ADR 2027 Table A changes →