Monitoring performance is one of the issues that must be addressed by the safety management system (SMS), but operators usually disregard it. By the experience gained during inspections on the SMS in establishments covered by Seveso II Directive, the unit of the regional agency for environmental protection (ARPA Piemonte) specialized in technological risk control (UCRT) has developed a methodology to improve this monitoring. It combines incident investigation and analysis of performance indicators, allowing operators to measure the achievement of the objectives stated in the major accident prevention policy and to evaluate their adequacy. On the basis of data collected during the inspections on the SMS about incidental events (major accidents, accidents and near misses), a database was organized, showing the most critical elements of the SMS that operators should improve. (C) 2004 Elsevier Ltd. All rights reserved.