8Recitals 2 to 6, 8, 11 to 13 and 17 of Regulation No 273/2004 state:(2) The requirements of Article 12 of the United Nations Convention in respect of trade in drug precursors (i.e. substances frequently used in the illicit manufacture of narcotic drugs and psychotropic substances) have been implemented, as far as trade between the Community and third countries is concerned, by Council Regulation (EEC) No 3677/90 of 13 December 1990 laying down measures to be taken to discourage the diversion of certain substances to the illicit manufacture of narcotic drugs and psychotropic substances [(OJ 1990 L 357, p. 1)].(3) Article 12 of the [Vienna Convention against Illicit Traffic] envisages adoption of appropriate measures to monitor the manufacture and distribution of precursors. This requires the adoption of measures relating to the trade in precursors among Member States. Such measures were introduced by Council Directive 92/109/EEC of 14 December 1992 on the manufacture and the placing on the market of certain substances used in the illicit manufacture of narcotic drugs and psychotropic substances [(OJ 1992 L 370, p. 76)]. To better ensure that harmonised rules are applied at the same time in all Member States, a regulation is considered to be more adequate than the current Directive.(4) In the context of the enlargement of the European Union, it is important to replace Directive 92/109/EEC by a regulation, as each modification of that Directive and its Annexes would trigger national implementation measures in 25 Member States.(5) By decisions taken at its 35th session in 1992, the United Nations Commission on Narcotic Drugs included additional substances in the tables of the Annex to the [Vienna Convention against Illicit Traffic]. Corresponding provisions should be laid down in this Regulation in order to detect possible cases of illicit diversion of drug precursors in the Community and to ensure that common monitoring rules are applied in the Community market.(6) The provisions of Article 12 of the [Vienna Convention against Illicit Traffic] are based on a system of monitoring trade in the substances in question. Most trade in these substances is entirely lawful. The documentation of consignments and labelling of these substances should be sufficiently explicit. It is furthermore important, whilst providing competent authorities with the necessary means, to develop, within the spirit of the [Vienna Convention against Illicit Traffic], mechanisms based on close cooperation with the operators concerned and on the development of intelligence gathering.…(8) Substances commonly used in the illicit manufacture of narcotic drugs or psychotropic substances should be listed in an Annex.…(11) Measures should be adopted in order to guarantee better control of intra-Community trade in scheduled substances listed in Annex I.(12) All transactions leading to the placing on the market of scheduled substances of categories 1 and 2 of Annex I should be properly documented. Operators should notify the competent authorities of any suspect transactions involving the substances listed in Annex I. However, exemptions should apply to transactions involving substances of category 2 of Annex I where the quantities involved do not exceed those indicated in Annex II.(13) A significant number of other substances, many of them traded legally in large quantities, have been identified as precursors to the illicit manufacture of synthetic drugs and psychotropic substances. To subject these substances to the same strict controls as those listed in Annex I would present an unnecessary obstacle to trade involving licences to operate and documentation of transactions. Therefore, a more flexible mechanism at Community level should be established whereby the competent authorities in the Member States are notified of such transactions.…(17) Since the objectives of this Regulation, namely the harmonised monitoring of the trade in drug precursors and the avoidance of its diversion to the illicit manufacture of synthetic drugs and psychotropic substances, cannot be sufficiently achieved by the Member States and can therefore, by reason of the international and changeable nature of such trade, be better achieved at Community level, the Community may adopt measures, in accordance with the principle of subsidiarity as set out in Article 5 of the Treaty. In accordance with the principle of proportionality, as set out in that Article, this Regulation does not go beyond what is necessary in order to achieve those objectives.’