Part III of the Protocol, which consists of 4 paragraphs, addresses the confidence-building measures of the Treaty. The purpose of these measures is to provide for an exchange of data and information that would help reduce ambiguities and promote confidence in Treaty compliance. Such measures could also reduce the likelihood of requests for on-site inspections.

The United States initially sought confidence-building measures that would be mandatory for all States Parties. Many other states preferred that confidence-building measures of the Treaty be only on a voluntary basis because they were concerned that mandatory measures might be overly burdensome, and they were also unconvinced of their utility. Ultimately, all states agreed that the confidence-building measures provided for in Part III of the Protocol are voluntary; there is no legal obligation to comply with these provisions. The U.S. intends to provide all information identified in paragraphs 1 and 2 of Part III.

Article IV, paragraph 68 of the Treaty provides that each State Party undertakes to cooperate with the Organization and other States Parties in implementing relevant measures as set out in Part III of the Protocol. Paragraph 1 of Part III of the Protocol provides that pursuant to Article IV, paragraph 68, each State Party shall, on a voluntary basis, provide the Technical Secretariat with notification of any chemical explosion using 300 tonnes or greater of TNT-equivalent blasting material detonated as a single explosion anywhere on its territory, or at any place under its jurisdiction or control. Paragraph 1 further provides that if possible, such notification shall be provided in advance. Such notification shall include details on location, time, quantity and type of explosive used, as well as on the configuration and intended purpose of the blast.

Paragraph 2 of Part III provides that each State Party shall, on a voluntary basis, as soon as possible after the entry into force of the Treaty, provide to the Technical Secretariat, and at annual intervals thereafter update, information related to its national use of all other chemical explosions greater than 300 tonnes TNT-equivalent. In particular, the State Party shall seek to advise:

(a) The geographic locations of sites where the explosions originate;

(b) The nature of activities producing them and the general profile and frequency of such explosions;

(c) Any other relevant detail, if available.

In addition, the States Parties shall seek to assist the Technical Secretariat in clarifying the origins of any such event detected by the IMS.

The U.S. understanding of these provisions is that the explosions referred to in paragraph 1 of Part III are events in which 300 metric tons or greater of TNT-equivalent blasting materials are detonated simultaneously, whereas the explosions referred to in paragraph 2 are events in which the cumulative energy release, whether released in a single explosion or with delays between the firing of individual charges, i.e. "ripple-fired," is greater than or equal to the energy release resulting from the detonation of 300 metric tons of TNT-equivalent blasting materials.

Paragraph 3 of Part III of the Protocol provides that a State Party may, on a voluntary and mutually-acceptable basis, invite representatives of the Technical Secretariat to visit sites within its territory referred to in paragraphs 1 and 2 above.

The final paragraph of Part III, paragraph 4, provides that for the purpose of calibrating the IMS, States Parties may liaise with the Technical Secretariat to carry out chemical calibration explosions or to provide relevant information on chemical explosions planned for other purposes. Since the purpose of this liaison is for calibration, information on chemical explosions given pursuant to this paragraph may be for such explosions below 300 tonnes of TNT-equivalent blasting material.