South Africa signed and ratified the Comprehensive Nuclear Test-Ban-Treaty (CTBT) and accordingly made commitments to the Organization (CTBTO). Of the obligations are the establishment of a Radionuclide Laboratory, the design, installation and operation and maintenance of a radionuclide particulate and noble-gas monitoring station and the nomination of one radionuclide specialist South African to serve on an international team for On-Site Inspection (OSI). The last to provide expertise when the worldwide monitoring network provides strong indications that an illegal nuclear test has been performed at the territory of a State Party. The inspection team will be equipped with amongst others radiation monitors and nuclide specific measuring equipment limited to report on specific radionuclides agreed upon by all State Parties. In real-time operational circumstances one may assume that all members of the team will not be registered radiation workers and accordingly be regarded as members of the public when radiation hazard is to be evaluated. In this paper we try to categorize the radionuclides of interest and evaluate the radiological risk to the OSI-team due to inhalation of airborne radioactive particulate matter during the survey at the site of an anticipated nuclear test. From this study recommendations will be made to the CTBTO for possible implementation of portable sampling and analysis equipment to allow on-site evaluation of the potential internal exposure of OSI-team members.