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ADR — transport of hazardous goods

Classification, labeling, documentation and 2025 rules

2026-06-14·14 min reading

ADR regulates road transport of dangerous goods in Europe. Here is the basic structure: classes, UN numbers, hazard labels, documentation, equipment, tunnel restriction categories A–E — and what is new with ADR 2025 and the new Danish regulation BEK 915/2025.

Introduction

ADR (L'Accord européen relatif au transport international des marchandises Dangereuses par Route) is the European convention on road transport of hazardous goods. It is updated every other year; the current version is ADR 2025, which came into force on January 1, 2025 (with a transition period so ADR 2023 could in principle be used until June 30, 2025).

The classes in ADR

ClassType of goodsExample
1Explosive substances and articlesFireworks, ammunition
2GasesPropane, compressed air, aerosols
3Flammable liquidsPetrol, diesel, ethanol
4.1 / 4.2 / 4.3Flammable solids / self-igniting / water-reactiveSulphur, white phosphorus
5.1 / 5.2Oxidising substances / organic peroxidesHydrogen peroxide, benzoyl peroxide
6.1 / 6.2Toxic and contagious substancesPesticides, clinical waste
7Radioactive substancesRadiopharmaceutical material
8Corrosive substancesSulphuric acid, sodium hydroxide
9Various hazardous substances and itemsLithium batteries, dry ice

UN number and hazard labels

Each dangerous substance has a UN number (UN XXXX) that uniquely identifies it. Hazard labels (orange plate with UN number + hazard class) are mounted visibly on the vehicle and packaging. Incorrect or missing hazard labels are serious violations.

Documentation and ADR certificate

  • 01Transport document: sender issues document with UN number class quantity/amount and emergency procedures
  • 02Written instructions (Safety Card): must be carried in the mother tongue for all countries involved.
  • 03ADR certificate: the driver must have a valid ADR training certificate for the relevant types of goods.
  • 04Safety advisor: companies with ADR shipments must have a certified advisor — notification is now only digital (Traffic Directorate's self-service ref. BEK 915/2025).

Transport categories and exempted quantities (ADR 1.1.3.6)

ADR has a system where small quantities can be transported without triggering the full requirements (orange plates, ADR certificate, full equipment) — this is called exempted packaging. Each substance has a transport category from 0 to 4, which determines how much can be carried per transport unit:

Transport categoryFree quantity per unitPoint factor
00 (not permitted below free amount)
120 kg / litre× 50
2333 kg / liter× 3
31000 kg / liter× 1
4unlimited× 0

Kører du blandet last fra flere kategorier, bruges 1000-points-reglen: gang mængden i hver kategori med pointfaktoren og læg sammen. Overstiger summen 1000, er frimængden overskredet, og de fulde ADR-krav gælder. Eksempel: 100 kg kategori 2 (100 × 3 = 300) + 300 kg kategori 3 (300 × 1 = 300) = 600 point < 1000 → stadig frimængde.

Orange hazard sign: hazard number and UN number

Full ADR transport must be marked with the orange label front and back (and on tanks per compartment). The label has two numbers: the hazard number (Kemler/HIN number) at the top, the UN number at the bottom.

  • 01Farenummerets første ciffer angiver den primære fare (2 = gas, 3 = brandfarlig væske, 8 = ætsende osv.).
  • 02A repeated digit (e.g. 33) means intensified/heightened hazard.
  • 03An »X« at the beginning means the substance reacts dangerously with water — do not use water.
  • 04At the bottom is the UN number (UN XXXX) that uniquely identifies the substance.
orange warning sign (front + back)Hazard number (Kemler / HIN)1. ciffer = primær fare — 3 = brandfarlig væskegentaget ciffer (33) = forstærket fare»X« foran = reagerer farligt med vandUN-nummerentydigt stof — UN 1203 = benzin
Fig. The orange hazard label: hazard number (Kemler/HIN) at the top, UN number at the bottom. The example is petrol — hazard number 33 (flammable liquid, intensified) over UN 1203.

Hazard labels per class

In addition to the orange placard, packaging and vehicles carry hazard labels (labels/placards) — the diamond-shaped symbols that show the hazard class with colour, symbol and class number at the bottom (e.g. flame for class 3, skull for class 6.1, black/yellow for radioactive class 7). Incorrect or missing hazard labels are serious violations.

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