Since 1987 at the Spedali Civili of Brescia the problem of anaesthetic gases pollution in operating surgery rooms was managed by means of periodical environmental monitoring and maintenance of the anaesthesiological equipments. The mean nitrous oxide concentrations were generally reduced to values below the limits indicated by the Italian Ministry of Health. On the contrary, a low participation of the operating room personnel was observed in the health surveillance program and this phenomenon is clearly evidenced by the progressive decrease of the number of medical examinations. In order to clarify the usefulness of health surveillance programs and to promote the adoption of "less pollutant" behaviour, a Health Education Program was planned by the Medical Administration, in collaboration with the Occupational Health Service and the Department of Anesthesiology and Intensive Care. This program will be performed at different times, including the administration of a questionnaire, the participation at information meetings, the distribution of brochures and the evaluation of environmental and biological exposure data before and after the education program.