Key Aspects of Challenge Inspections

Inspection training held in Italy.

Part X of the Verification Annex contains detailed guidelines for the conduct of challenge inspections. The main factors to be considered are:

Quick response

In order for a challenge inspection to be effective, the quick dispatch and arrival of the inspection team and strict observance of specified time frames is crucial.

The Convention provides that the inspection team is to arrive at the Point of Entry (POE ) not earlier than 12 hours after the inspected State Party  (ISP) has been notified. Mounting such a rapid response involves considerations of the nature of the challenged site, the concerns expressed in the inspection request, availability of transport, the size of the inspection team and the type and amount of equipment needed.


The ISP must transport the team from the POE to the inspection site within 36 hours of its arrival. Further time frames and inspection procedures may vary depending on whether the challenged site has been declared by the ISP under Articles IV, V and VI.


A number of issues are of crucial importance once the inspection team arrives in the ISP. The team and the ISP must first agree on a perimeter for the inspection site. Perimeter negotiations can continue for a maximum of 72 hours from the team’s arrival at the POE.


During a challenge inspection, the ISP can apply “managed access” measures in order to protect any information not relevant to the Convention’s purposes. These may include shrouding displays, restricting sample analysis to simple determination of the presence or absence of scheduled chemicals and requesting that inspectors randomly select from within the site a certain number of buildings for inspection. The ISP is obliged to make a reasonable effort to demonstrate compliance.

At declared sites, the inspection team has unimpeded access within the boundaries established by a facility agreement between the ISP and the Secretariat, or in line with applicable general inspection guidelines if there is no facility agreement. Subject to the agreement of the ISP, an observer from the RSP may visit the inspection site and make recommendations to the inspection team; these are taken into account to the extent deemed appropriate.


As in routine inspections, the team can take samples, which are either analysed on-site or transferred off-site for analysis at an OPCW designated laboratory. The inspection cannot exceed 84 hours, unless the ISP agrees to an extension. Following the inspection, the team draws up its preliminary findings. These are discussed with the ISP National Authority at a debriefing which cannot last beyond 24 hours from the time the inspection has finished.


With the inspection over, a preliminary inspection report must be submitted to the Director-General within 72 hours of the team arriving back in The Hague. This report is transmitted to the RSP, the ISP and the Executive Council. Within the next 20 days, a draft final inspection report must be made available to the ISP, which has the right to propose changes to it. The Secretariat is to consider the suggested changes and, using its discretion, adopt them wherever possible. The final report is submitted to the Director-General within 30 days of the end of the inspection and is transmitted further to the ISP, RSP, Executive Council and all other States Parties. The Council reviews the report and the views of the ISP, RSP and any other States Parties and reports its findings to the Conference. If the right to request a challenge inspection was judged to have been abused, the Council is to examine whether the RSP should bear any financial costs.

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Relevant CWC Provision

  • Consultations, Cooperation and Fact-Finding (Article IX)

Did You Know?

Only specifically designated inspectors can participate in challenge inspections. Nationals of the inspected State Party and the requesting State Party are excluded from the team.