Economic activity "collection, disposal and treatment of waste water" is especially risky in terms of working conditions. A significant proportion of workers in this activity are regularly exposed to humidity and low temperatures. Particularly significant and causing serious damage to the health of employees impact of materials that can cause infectious diseases. Additional physical and psychological stress has and the fact that employees must comply with stringent quality standards. In order to facilitate the risk assessment process, the European Agency for Safety and Health at Work – Bilbao (EU-OSHA) has developed a comprehensive user-friendly free web application, OiRA (an interactive risk assessment online tool), which helps micro and small enterprises to perform an overall step-by-step risk assessment – from identifying and assessing risks at work, making and implementing decisions on preventive measures, to continuous monitoring and reporting.