Our thesis is in line with a first research work in which we highlighted the use by OSH to accommodation of some instructions during safety inspections. This has raised new questions about the consequences of this phenomenon on the health of the OSH but also on the performance of the safety management system. Our thesis then focused on the characterization of the difficulties encountered by OSH during problem solving sequences initiated by the detection of deviations from the prescription safety during the visit, but also on identifying methodological determinants that are at the origin. Three methods were used: statement traces of the activity using the method of the agenda, open observations of the activity of a sample of OSH enterprises and systematic observations visit phases security coupled with verbalisation techniques. The main results of this thesis are: (i) OSH in companies only spend very little time for safety inspections, (ii) the phenomenon of "desertion" of the land can’t be solely explained by the weight of administrative tasks (iii) the temporal context in which are carried out safety inspections and the lack of media artifact exchanges, do not favor the development of cognitive synchronization phenomenon, since all differences are not explicitly approved by surveying the solutions of all interlocutors, (iv) OSH develop defense strategies reducing the effects of this lack of performance on their health, (v) changes in the temporal context and the integration of video artifacts facilitating trade, allows improved performance in terms of deviations lifted; the solutions produced are then more numerous and more complex, exchanges are richer and constraints are better managed. The results of this thesis allow both to continue with the characterization of the work of OHS in companies, to account for the effects of self-confrontation on interviewers but also to offer an artifact design method based on the instrumental approach which facilitates ownership.