UN 2421 — ADR 2025 Table A: class 2, classification code 2TOC, packing group — (CARRIAGE PROHIBITED), labels —, special provisions —, limited quantity —, excepted quantity —, packing instructions —, transport category —, tunnel restriction code —, hazard identification number —.

UNECE ADR 2025, ECE/TRANS/352 · checked 2026-10-28

Table A — ADR 2025 (ECE/TRANS/352), UN 2421
(1) UN No.	2421
(2) Name and description	NITROGEN TRIOXIDE
(3a) Class	2
(3b) Classification code	2TOC
(4) Packing group	CARRIAGE PROHIBITED
(5) Labels	—
(6) Special provisions	—
(7a) Limited quantities	—
(7b) Excepted quantities	—
(8) Packaging: packing instructions	—
(9a) Packaging: special packing provisions	—
(9b) Packaging: mixed packing provisions	—
(10) Portable tanks and bulk containers: instructions	—
(11) Portable tanks and bulk containers: special provisions	—
(12) ADR tank: tank code	—
(13) ADR tank: special provisions	—
(14) Vehicle for tank carriage	—
(15) Transport category (Tunnel restriction code)	—
(16) Special provisions for carriage: packages	—
(17) Special provisions for carriage: bulk	—
(18) Special provisions for carriage: loading, unloading and handling	—
(19) Special provisions for carriage: operation	—
(20) Hazard identification No.	—

ADR 2027 (accepted) — no change for UN 2421

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)

ADR 2027: no Table A change for this entry (checked against ECE/TRANS/WP.15/274, Add.1 and Corr.1). 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 →Check a list of UN numbers →

Class 2 — GasesCarriage prohibited

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