Most trafficking is carried out in secrecy and is divorced from legal commerce. However, precursors trafficking often intersects with legitimate commerce or customs controls, e.g. in order to source materials or transport shipments.

These cross over points provide an opportunity to stop incidents of trafficking by using regulatory and interdiction tools. Monitoring the procurement of and trade in the chemicals necessary to manufacture and process drugs is such a tool.

Legislation and Control Measures

The concerted and united efforts of Governments determined to establish measures to prevent the diversion of precursor and essential chemicals into the illicit manufacture of drugs led to the United Nations Convention Against Illicit Traffic in Narcotic Drugs and Psychotropic Substances of 1988 (1988 Convention ), and today the Convention enjoys near universal adherence. The 1988 Convention contains detailed provisions and requirements relating to the control of precursors. The general requirements are summarized in paragraph 1 of article 12:

"The parties shall take the measures they deem appropriate to prevent diversion of substances in Table I and Table II used for the purpose of illicit manufacture of narcotic drugs or psychotropic substances, and shall co-operate with one another to this end."

Under the treaty, the International Narcotics Control Board has a special responsibility to monitor Governments' control over precursors and other chemicals used in the illicit manufacture of drugs, and to assist them in preventing the diversion of those chemicals into the illicit traffic. Every year, the Board publishes a report on the implementation of article 12 of the 1988 Convention (see the Precursors Annual Reports).

The international precursors control system has been challenged by the spread of non-scheduled chemicals and designer precursors that are used in illicit drug manufacture. Frequently, these chemicals are characterized by being closely related with a controlled precursor, and some of them have no known legitimate and industrial use. They can be made-to-order to specifically circumvent existing legislation and controls. The Board has developed several relevant tools and resources, which are outlined below.

In addition to the 1988 Convention, Government initiatives in the field of precursors control have been further supported through resolutions from the General Assembly, the Economic and Social Affairs Council as well as the Commission on Narcotic Drugs, and have led to the creation of flexible control mechanisms.

Tools and resources

With the 1988 Convention and related resolutions as the legal basis for a flexible approach to precursor control, governments can, in partnership with industry, quickly identify suspicious shipments and prevent diversion (Tools and Kits for National Competent Authorities). An operational dimension has also been integrated into the approach, with successful operations conducted under the banners of Projects Prism and Cohesion. Furthermore, resources have been developed, such as PEN Online, PICS and a compilation of practical, precursor-related recommendations from the Board's precursors annual reports, which actively and effectively support Governments in working towards the objectives of the Convention. A number of these resources are only available to Competent National Authorities, in the Secure Area containing CNA reference material.

Tools and resources addressing non-scheduled chemicals and designer precursors

An interactive compendium below is a one-stop shop of information on tools and resources to address the diversion of non-scheduled chemicals frequently used in the illicit manufacture of drugs and the proliferation of designer precursors.


Download the interactive pdf (multi-page) - best viewed on desktop (Microsoft Edge, Chrome)

Download the interactive pdf (one-page summary) - best viewed on desktop (Microsoft Edge, Chrome)

Other practical information on how address the proliferation of non-scheduled chemicals and designer precursors that is available to competent national authorities is contained in the INCB guidance document on practical options and measures (available in all UN languages), as well as a Conference Room Paper prepared for the March 2020 session of the Commission on Narcotic Drugs.


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