ADR 2.1.3.5.5: Unknown Waste UN Entry Classification
Question asked to Palen
Revised on Sep 1, 2026
↗A client wishes to ship a mixture of waste consisting of paints, solvents and contaminated absorbents. The exact products can no longer be identified. What ADR procedure can be used to assign a defensible UN entry in the event of an inspection?
Use the unknown-composition waste classification procedure in ADR 2.1.3.5.5. It is specifically intended for waste whose composition is not precisely known and permits assignment to a UN number and packing group using the consignor’s documented knowledge of the waste, together with all available technical and safety data. Where doubt remains, the highest level of danger must be selected. (ADR 2.1.3.5.5, Volume 1, page 105)
Operational application
Establish the credible hazard envelope from collection records, waste-stream origin, previous paint/solvent SDSs, labels, analytical results, odor/physical state, flash-point or other screening results, and the nature of the contaminated absorbents. This forms the defensible classification file. (ADR 2.1.3.5.5, Volume 1, page 105)
Classify under the appropriate collective “n.o.s.” entry, rather than assume that the waste remains a paint entry merely because paints are present. The relevant class, subsidiary risks, and packing group must reflect the hazards established for the mixed waste. Where competing class hazards exist, select the class using the ADR precedence-of-hazards table. (ADR 2.1.3.5.4, Volume 1, page 105)
Apply the conservative packing-group rule. If the evidence cannot exclude Packing Group I, classify at the highest credible danger level. Only where the documented knowledge of composition and the physical/chemical properties of identified components demonstrate that PG I properties do not apply may the waste be assigned by default to the most appropriate n.o.s. entry in Packing Group II. (ADR 2.1.3.5.5, Volume 1, page 105)
For this waste stream, the defensible approach in an inspection is therefore not a blanket UN 1263 “PAINT” assignment. It is a written ADR 2.1.3.5.5 assessment that identifies the credible hazards of the liquid/solid waste mixture, selects the corresponding collective n.o.s. UN entry and subsidiary risks, and demonstrates why the selected packing group is conservative. The packaging, marks/labels, transport document, loading controls, equipment, and any tunnel restrictions must then be taken from the final selected Table A entry.