Subheading 2904 99 of the Combined Nomenclature is the residual category within heading 2904 and covers other sulphonated, nitrated and nitrosated derivatives of hydrocarbons that do not fall under subheading 2904 10 (sulphonated only) or 2904 20 (only nitro or nitroso groups). This includes compounds bearing combinations of functional groups — for example, nitrosulphonic, chloronitro, and mixed-substituent derivatives which, under Note 1 to Chapter 29 CN, must be separately chemically defined organic compounds. Examples of goods in this subheading include nitrochlorobenzene (para-chloronitrobenzene — a precursor for dyes and pharmaceuticals), nitrobenzenesulphonic acid, nitroanisole and nitronaphthalene. Correct classification under 2904 99 requires first excluding subheadings 2904 10 and 2904 20 by analysing the functional groups present in the molecular structure. The chemical structure must be confirmed by analytical data or producer technical documentation. The General Rules for the Interpretation of the CN, in particular Rule 6 for subheadings, apply at the final stage of classification.

Substances imported under subheading 2904 99 are organic chemicals subject to REACH Regulation (EC) No 1907/2006. An importer from outside the EU becomes legally responsible for substance registration with ECHA where the annual import volume reaches 1 tonne or more. Many substances in this subheading — for example nitrochlorobenzene — are toxic to aquatic organisms and classified under CLP Regulation (EC) No 1272/2008 as hazardous to human health or the environment. Correct labelling and packaging in compliance with CLP is a legal requirement before placing the substance on the EU market. A Safety Data Sheet (SDS) compliant with Regulation (EU) 2020/878 must be drawn up in the official language of the country of delivery and contain all 16 mandatory sections, including hazard classification and first aid measures. Some substances in this group may appear on the ECHA SVHC (Substances of Very High Concern) candidate list or be subject to restrictions under Annex XVII of REACH. The importer should verify the status of each substance in the ECHA C&L Inventory and SVHC list. During transport, ADR (road), IMDG (sea) or IATA (air) regulations apply according to the CLP hazard classification.

MFN duty rates for goods under subheading 2904 99 of the Combined Nomenclature must be verified in the European Commission's TARIC database, as they are subject to change through tariff reviews and autonomous suspensions. Autonomous tariff suspensions (Council EU regulations on tariff suspensions) may apply to chemical substances unavailable or not produced in the EU in sufficient quantity or quality — importers may request a suspension from the European Commission. Preferential duty rates are available under Free Trade Agreements (CETA, EU-Japan EPA, EU-South Korea FTA, EU-UK TCA) and the GSP for developing countries. Their application requires compliance with rules of origin and presentation of an EUR.1 certificate, invoice declaration or REX statement. The importer should verify in TARIC whether anti-dumping or other protective measures apply to the specific goods and country of origin. The legal basis for import is the Union Customs Code (Regulation (EU) No 952/2013). All duty rates and trade measures should be verified in the current TARIC database.

Organic substances under CN code 2904 99 (other nitrated sulphonated derivatives) require detailed chemical documentation for customs clearance. The Safety Data Sheet must comply with REACH Annex II. Substances classified as hazardous under CLP require GHS pictogram labelling. Transport follows ADR (road) or IMDG (maritime) regulations. Some organic substances may be subject to export controls as dual-use goods. Importers should verify whether the substance requires REACH authorisation (Annex XIV) or is subject to restrictions (Annex XVII).