Some of the instruments and methods described in our Working Paper are already available to inspection teams confronted with the task of verifying compliance effectively in the least intrusive manner. They have proved, under increasingly realistic circumstances, to be extremely useful in the conduct of different types of inspections, whether ad hoc or challenge. Others are being developed under our national research and development programme on verification instrumentation. Another issue in the field of verification is ad hoc verification. We consider this to be an important element, complementing and strengthening the verification of non-production in article VI. As early as January 1988, we submitted a proposal on ad hoc checks in order to make a constructive contribution to resolving a problem that was raised by a number of delegations: the potential of existing facilities in the chemical industry, in particular those which are not declared under any of the annexes to article VI, to produce chemical weapons. We conceive of ad hoc verification measures to be a non-intrusive instrument of a routine character, its main purpose being to verify the absence of substances listed in the "Annex on chemicals". Such non-intrusive checks would cover those parts of industry which might possibly be misused for the production of chemical weapons. As with other routine verification measures, the selection of facilities to be inspected by ad hoc verification measures would be made on the basis of the declarations to be submitted by all States parties. These declarations would be made in the form of national registers which, in accordance with an agreed format, would list all relevant plant sites of the chemical industry. We have made a specific and concrete proposal on the establishment of national registers in document CD/984 of 10 April 1990. The reactions we have 
**Analysis**
The text appears to be discussing international agreements and verification methods related to the production and use of chemical weapons. The language used is formal and technical, suggesting a context of international diplomacy and treaty-making. The text references specific documents and dates, indicating a focus on a specific issue or agreement. Given these characteristics, it is likely that the text is related to a category that involves international cooperation, treaties, and verification methods.

**Category**
International trade, Science and technology