6.9. A detailed programme of site characterization should be carried out to provide the site specific data necessary to support the technical basis for safety assessments of the long term isolation and containment of the waste within the excavated portion of the geological disposal facility. Quantitative data of a level of detail sufficient for their end use should be obtained (in terms of accuracy and precision of the data and their representative nature with regard to spatial and temporal variability). Appendix I provides additional guidance on the types of information that are expected from a programme for site investigation and characterization. However, the listing may not be exhaustive and site specific circumstances will ultimately dictate what information is required and in what detail.