Categories of Precursor Chemicals
The 1988 UN Convention lists drug precursor chemicals in two tables. Table I contains substances which can be converted readily to controlled drugs or are essential for drug manufacturing. Table II contains other chemicals such as solvents and reagents commonly used for drug processing.
In the EU regulations, all of the chemicals in the UN Tables I and II are broken down into four categories based on the risk they pose balanced against their level of legitimate use. This difference allows a greater flexibility in the application of controls, checks and monitoring.
The EU regulations include additional precursor chemicals that have been used in illegal drug manufacture in the EU. Each category has differing requirements under the main pieces of legislation.