The Biological Weapons Convention requires Parties not to develop, produce, stockpile, or acquire biological agents or toxins "of types and in quantities that have no justification for prophylactic, protective, and other peaceful purposes," as well as weapons and means of delivery. The United States unilaterally renounced biological and toxin weapons in 1969.

The Biological Weapons Convention was opened for signature in April 1972 and the United States submitted its instruments of ratification in March 1975. The United States, along with the United Kingdom and the Russian Federation, are the three depositary governments for the Convention. There are currently some 139 States Parties with an additional 18 countries who have signed but not ratified the Convention.

There have been three Review Conferences to the BWC, each taking place in Geneva. The First Review Conference was held in 1980. At the Second Review Conference in 1986, the Parties agreed on a set of confidence building measures (CBMs), including the following: exchanging data on research laboratories that meet very high national or international safety standards established for handling, for permitted purposes, biological activities; sharing information on all outbreaks of infectious diseases or similar occurrences caused by toxins which deviate from the normal; encouraging publication of results of biological defense research in scientific journals generally available to the public; and promoting scientific contact, including joint research projects directly related to the Convention. The United States has implemented these CBMs and routinely submits data to the United Nations, according to procedures of the Final Declaration of the 1986 Review Conference.

At the Third Review Conference in 1991 States Parties were determined to strengthen the CBMs and to enhance confidence in the implementation of the Convention. In addition to strengthening the existing CBMs, States Parties added two additional CBMs: Declaration of past activities in offensive and/or defensive biological research and development programs; and Declaration of vaccine production facilities. Unfortunately, participation by States Parties in submitting data has been somewhat disappointing with some 70 countries having submitted at least one declaration since inception. In a further effort to strengthen the effectiveness and improve implementation of the Convention, States Parties mandated the convening of an Ad Hoc Group of Governmental Experts to identify and examine potential verification measures from a scientific and technical standpoint. That Ad Hoc Group (also known as VEREX) held four sessions in Geneva between March 1992 and September 1993. As provided in the mandate, a Special Conference to discuss the VEREX Final Report and to consider further actions was convened in September 1994. The Conference agreed to establish an Ad Hoc Group, open to all States Parties, to consider appropriate measures, including possible verification measures, and draft proposals to strengthen the Convention in a legally binding instrument.

The Ad Hoc Group (AHG) held three meetings in 1995, a procedural meeting and two substantive meetings in 1996, each of two weeks duration. The work of the AHG is divided into four Friends of the Chair, consistent with the categories established by the Special Conference. They are: Definitions and Objective Criteria; Confidence Building Measures (CBMs); Measures to Promote Compliance; and Article X (technology transfer). An Ad Hoc Group Progress Report will be submitted to the Fourth Review Conference scheduled to convene in Geneva, November 25-December 6, 1996.