What should the marking/labeling include?
Understanding ADR obligations

All packages containing dangerous goods must be marked and labelled.

Marking consists in clearly and durably displaying on the package, in accordance with point 5.2.1 "Marking of packages", the UN code preceded by the letters "UN" of the goods in the package, e.g. UN1950 on a carton of aerosols.

There are "Special provisions for the marking of environmentally hazardous substances" (5.2.1.8 of the ADR), specifying that packages containing environmentally hazardous substances must bear the "environmentally hazardous substance" mark, except in the case of packages having :

• a quantity ́ less than or equal to 5 l for liquids;

• a net mass of 5 kg or less for solids.