The Author describes the process of chemical risk assessment to be implemented in the workplace, which must lead to the characterization of risk, and thus to estimate the probability of adverse health effects can occur. It is a multi-step and multi-disciplinary activity carried out in close collaboration between the Head of Prevention and Protection Service (which is able to use the accountability of managers and supervisors and the involvement of representatives of workers' safety) and occupational physician who, through its cross-training, can and should be the connective tissue of the entire operation: in fact he is the only professional figure able to link together health and safety in the workplace. The Author recalls the importance of using biological monitoring procedure, which must always be used especially when the evaluation is to use simplified measures such as algorithms.