There are over twenty distinct types of on-site inspection (OSI) included in the arms control agreements signed since the Intermediate-Range Nuclear Forces (INF) Treaty was concluded in December 1987. Each type of inspection has its own peculiarities crafted to accomplish a specific, sometimes highly technical, verification task. In general, however, the inspections in the major arms control agreements fall within four broad categories. They are designed to: 1) assist in confirming treaty-related data during the baseline period and thereafter; 2) help verify that all parties are complying with treaty provisions at declared sites, that is, those sites that are listed in the treaty or related documents; 3) confirm that the required destruction or conversion of military weapons is being carried out strictly in accordance with the agreed procedures; and 4) help resolve ambiguous situations, or detect cheating if it is occurring, at a suspected site whether or not the site is listed in treaty documents. Data and routine compliance inspections are discussed below; elimination and conversion inspections are covered in chapter 6; and suspect-site and challenge inspections are presented in chapter 7. Perimeter and portal continuous monitoring and other on-site monitoring regimes have unique qualities and are dealt with in chapter 8.
Inspections designed primarily as confidence- and security-building measures (CSBMs) are not covered in this study. These include overflight inspections under the Open Skies Agreement; the inspection of member state military force structures and activities codified in the Vienna Document 1994 and its predecessors developed by the Organization for Security and Cooperation in Europe (OSCE); and the inspections contained in the Dayton Accord on Bosnia.
Data inspections, routine compliance inspections, and elimination and conversion inspections employ mutually agreed procedures contained in the treaty text. Such inspections typically take place at sites listed in the treaty, called declared sites. These are primarily military or government operational, storage, repair, training, or destruction facilities, although private industrial