About 75 per cent of private slope owners know they are responsible for maintenance but only 41 per cent maintain them to an acceptable standard, according to 1996 surveys of 100 privately-owned slopes by the Hong Kong University and the Geotechnical Engineering Office. 'To address this problem, the GEO is stepping up publicity to encourage pro-active private slope maintenance and the Government is considering legislation that will compel owners to maintain their slopes,' S. H. Mark, chief geotechnical engineer for slope safety, said. 'Many multi-storey buildings have numerous owners, so how can we help them get together to arrange for necessary maintenance? 'If they don't take action - do we penalise them all? If we have mandatory owners' corporations, there is a body to get things done,' he said. Currently, if a privately-owned slope is sub-standard, the GEO will recommend a dangerous hillside (DH) order be served by the Buildings Department. 'The order requires the owner to carry out investigation or upgrade works on the slope. But the slope must be dangerous or liable to become dangerous before we can issue an order - then it might be too late,' he said. The details of private substandard slopes are made available to the public by the Buildings Department subject to DH orders. 'To ensure we police slope safety effectively, we need to catalogue slopes so that they can be studied in a systematic way,' Mr Mak said. A major re-cataloging exercise is being carried out to prepare a complete inventory of sizeable man-made slopes. Based on the latest estimate, the number is 60,000. Only 30 per cent, or 18,000, have been checked to modern safety standards. The updated catalogue will be available to the public via the Internet at the end of the year on the Civil Engineering Department's (CED) homepage ( http://www.info.gov.hk/ced ) The location and details of substandard government slopes are kept in the CED's library. 'Most of the slopes that do not meet current safety standards were created before the CEO was established in 1977,' Mr Mak said. In view of the large number of pre-GEO slopes, priority for safety screening follows the 'worst-risk-first' principle. Immediate action is given to large steep slopes adjacent to public housing blocks, residential buildings, schools and hospitals. The GEO provides a 24- hour automated telephone hotline dedicated to slope safety. Assistance to private owners of slopes is provided in the form of Geoguide 5 and The Layman's Guide To Slope Maintenance.