6.24. This Safety Guide applies to a wide range of types of waste and disposal facilities and, depending on site specific and facility specific characteristics; these may pose different levels of hazard and risk. A graded approach to the safety case and supporting safety assessment is, therefore, required to be used to take account of the different levels of hazard and risk. Thus, it could be expected that greater levels of effort should be put into developing the safety case and safety assessment for disposal facilities for high level waste than for disposal facilities for low level waste and for landfill type disposal facilities. While this may be generally correct, a safety case and thorough safety assessment are still necessary for disposal facilities for low level waste, the detail of which will depend on site factors, facility design, the characteristics of the waste to be disposed of and other factors. Some parts of the safety case and assessment for a near surface disposal facility may even need more effort than for geological disposal facilities. An example is assessment of human intrusion, which may be considered an event of low significance for a well sited geological disposal facility but may be considered almost inevitable for a near surface disposal facility. The level of detail necessary in the safety case and assessment should be determined by first undertaking a relatively simple assessment that provides an indication of the levels of possible risk associated with the facility.