Workplace assessment is a critical issue in small firms, and even in bigger ones if workers are scattered in large working areas. The traditional "top-down" approach, based on centralized risk assessment and hardly understandable documents, may have limited impact on workers' safety behaviour. The Local Sanitary Unit RMF tried to improve workers' participation to risk assessment, through auditing techniques. Waste workers signalled occupational condition of biological and chemical risk, which had not been taken into account in the Corporate Risk Assessment Document. The participatory approach to workplace risk assessment proved to be an easy and not expensive method to increase workers' awareness of risk and compliance to hygienic measures.