UN 2257

POTASSIUM

UN 2257 — ADR 2025 Table A: class 4.3, classification code W2, packing group I, labels 4.3, special provisions —, limited quantity 0, excepted quantity E0, packing instructions P403 IBC04, transport category 1, tunnel restriction code (B/E), hazard identification number X423.

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

Table A — ADR 2025 (ECE/TRANS/352), UN 2257
(1) UN No.2257
(2) Name and descriptionPOTASSIUM
(3a) Class4.3
(3b) Classification codeW2
(4) Packing groupI
(5) Labels4.3
(6) Special provisions—
(7a) Limited quantities0
(7b) Excepted quantitiesE0
(8) Packaging: packing instructionsP403 IBC04
(9a) Packaging: special packing provisions—
(9b) Packaging: mixed packing provisionsMP2
(10) Portable tanks and bulk containers: instructionsT9
(11) Portable tanks and bulk containers: special provisionsTP7 TP33
(12) ADR tank: tank codeL10BN(+)
(13) ADR tank: special provisionsTU1 TE5 TT3 TM2
(14) Vehicle for tank carriageAT
(15) Transport category (Tunnel restriction code)1 (B/E)
(16) Special provisions for carriage: packagesV1
(17) Special provisions for carriage: bulk—
(18) Special provisions for carriage: loading, unloading and handlingCV23
(19) Special provisions for carriage: operationS20
(20) Hazard identification No.X423

ADR 2027 (accepted) — no change for UN 2257

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 →

In plain words

Tunnels
Tunnel code (B/E): in tanks, Prohibited in B, C, D, E; in other carriage, Prohibited in E. Tanks: A only. Packages: A, B, C, D. (ADR 8.6.4; from the ADR table itself)
Small-load exemption
Transport category 1: at most 20 per transport unit under 1.1.3.6, counted ×50 toward the 1,000-point limit (ADR 1.1.3.6.3; from the ADR table itself)
Labels
Labels: model 4.3 (Substances which emit flammable gases in contact with water) (ADR 5.2.2.2.2, label model No. 4.3; paraphrase, not yet reviewed)
Packing
Packing instruction P403: Hermetically sealed solids packagings: combination (inners glass 2 kg, plastics 15 kg, metal 20 kg), single drums/jerricans, composites, pressure receptacles. Packing instruction IBC04: Solids under IBC04 may go only in metal IBCs (11A, 11B, 11N, 21A, 21B, 21N, 31A, 31B, 31N). Mixed packing provision MP2: No mixed packing: the goods must be alone in their package. (ADR 4.1.4.1, P403, 4.1.4.2, IBC04, 4.1.10.4, MP2; paraphrase, not yet reviewed)
Tanks
Portable tank instruction T9: Portable tank, Class 1 and 3–9: test 4 bar; shell 6 mm; relief Normal; bottom openings Not allowed. Portable tank provision TP7: Air must be removed from the vapour space, by nitrogen or another method. Portable tank provision TP33: The assigned tank instruction covers granular/powdered solids and solids loaded hot but carried as a solid mass. Tank code L10BN(+): ADR tank code for Classes 1 and 3–9: liquid tank, 10 bar, openings B, valves/devices N, suffix (+). — L: tank for liquid-state substances (liquids, or solids handed over molten); 10: minimum calculation pressure of 10 bar (see 6.8.2.1.14); B: filling or discharge openings at the bottom, each with 3 closures; N: has no 6.8.2.2.6 breather device and is not hermetically closed; (+): alternative use of the tank for other substances is allowed only where the certificate of type approval says so (3.2.1 column (12); 4.3.4.1.3) Tank provision TU1: Tank may only be handed over once the substance has fully solidified under an inert gas blanket; empty uncleaned tanks are filled with inert gas. Tank provision TE5: Where shells have thermal insulation, it must be made of materials that are not readily flammable. Tank provision TT3: Periodic inspections at most every eight years with an instrument thickness check; leakproofness test and check at most every four years. Tank provision TM2: Tanks must additionally be marked "Do not open during carriage" and "Gives off flammable gases on contact with water". Vehicle for tank carriage: AT — Tank vehicle for dangerous goods that is not EX/III, FL or a MEMU: tanks over 1 m³ / 3 m³, or battery-vehicle over 1 m³. (ADR 4.2.5.2.6, portable tank instruction T9, 4.2.5.3, TP7, 4.2.5.3, TP33, 4.3.4.1.1, tank code L10BN(+), 4.3.5, TU1, 6.8.4 (b), TE5, 6.8.4 (d), TT3, 6.8.4 (e), TM2, 9.1.1.2, AT vehicle; paraphrase, not yet reviewed)
Carriage
Carriage provision V1: Packages must go on a closed or sheeted vehicle or in a closed or sheeted container; open vehicles and containers are not allowed. Loading provision CV23: Take special measures when handling packages so they never come into contact with water. Operation provision S20: Chapter 8.4 supervision applies above 10 000 kg in packages, or above 3 000 litres in tanks. (ADR 7.2.4, V1, 7.5.11, CV23, 8.5, S20; paraphrase, not yet reviewed)

Assembled from FreightUtils' meanings of the Table A codes, not the official text. A statement marked “not yet reviewed” has not yet been checked against ADR by a person.

Class 4.3 — Flammable SolidsPacking Group I
UN 2257Class 4.3 — Flammable SolidsPG I
Packing Group
I
High danger
Classification Code
W2
Tunnel Code
(B/E) meaning →
Code governing tunnel passage
Transport Category
1
For the 1,000-point rule (0 = highest restriction)
Hazard ID No.
X423
Kemler code
Limited Quantity
0
Max per inner package for LQ relief
Excepted Quantity
E0
EQ code for excepted quantity relief
Thresholds — why, not just the verdict
Transport Category
Category 1
×50 points per kg/L — up to 20 kg/L of this substance alone stays under the 1,000-point threshold
Per-substance max
20 kg/L
Per-substance maximum for 1.1.3.6 relief (1.1.3.6.3)
Limited Quantity
Not permitted
No limited-quantity relief for this entry (Chapter 3.4)
Excepted Quantity
E0
No excepted-quantity relief for this entry (Chapter 3.5)
Tunnel Code
Governs which tunnel categories the load may pass
Hazard Labels Required
Label 4.3

These labels must be displayed on packages and vehicle placards in accordance with ADR 2025.

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Other Flammable Solids near UN 2257 (Class 4.3)

UN 2010
MAGNESIUM HYDRIDE
UN 2011
MAGNESIUM PHOSPHIDE
UN 2012
POTASSIUM PHOSPHIDE
UN 2013
STRONTIUM PHOSPHIDE
UN 2463
ALUMINIUM HYDRIDE
All Class 4.3 UN numbers →
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📅Data: UNECE ADR 2025 (ECE/TRANS/352), via EU Directive 2008/68/EC. Last verified October 2026

ADR reference data only. Classification is the consignor's legal responsibility. Consult a DGSA for compliance decisions.

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