SUMMATIVE STATEMENT: In order to better understand pesticide exposure situations during the use of sprayers, this study aims at identifying and understanding a specific chain of determinants based on analysis conducted at different levels: the treatment activities, the activities of sprayer design, the regulation that applies to this design and the activities of regulation development. KEYWORDS: ergotoxicology, pesticide exposure situations, sprayer design, prevention, regulation PROBLEM STATEMENT: During the implementation of treatments that aim at protecting fields, farmers encounter numerous pesticide exposure situations due to the articulation of a diversity of determinants (PPE, workspaces, products used, etc.). Among these determinants, various studies have already highlighted the role played by the sprayer in the emergence of these situations due to its design (Albert et al., 2021; Goutille, 2022; Jolly, 2022). Regarding the prevention of pesticide exposure, the collective report by Laurent et al. (2016) highlighted the ineffectiveness of certain regulations and that farmers’ needs are insufficiently taken into account during the design processes. OBJECTIVE/QUESTION: The main objective of this research aims at question the ability of sprayer design processes and the regulations that apply to this design to offer adequate protection when farmers use sprayers. Thus, design and regulation are appropriate determinants to investigate in order to resolve, at least partially, the enigma of these exposures. We propose to articulate different levels of analysis of a particular chain of determinants in order to clarify the role played by design and regulation in the emergence of pesticide exposure situations during the use of sprayers. METHODOLOGY: The chain of determinants contains four levels of analysis. For the first level, i.e. treatment activities, an ergonomic analysis of the activity of sprayers users was conducted in five farms: filmed observations, driving activity and visual behavior analysis with eye-tracking glasses, self-confrontation interviews and hand-washing water samples to estimate the skin contamination. For the second level, i.e. design activities, an ergonomic analysis of the activity of sprayer design was conducted with a manufacturer: observations, collection of documents and interviews with six designers. For the third level of analysis, i.e. regulations that applies to the design, interviews with designers were supplemented by an analysis of the content of the regulations applicable to sprayer design and interviews with nine people in charge of regulation drafting process. For the last level, i.e. activities of regulation development, we used the same analysis methods described in the previous level (analysis of the content of regulations and interviews with the people in charge of regulation drafting process). RESULTS: The ergonomic analysis of treatment activities highlights the fact that farmers encounter many issues during the use of their equipment, which leads, in most cases, to situations of pesticides exposure. To that extent, the design of sprayers turns out to determining in the emergence of these situations. Indeed, the analysis of the design activities show that design choices reflect a lack of understanding of the winegrowers’ activity and the associated risks of pesticide contamination. Although regulation requirements could serve as a resource to include health and safety matters in the design, the analysis of their content reveals the same deficiencies. The analysis of the activities of rules development shows that the economic criterion holds a predominant position, sometimes at the expense of other criteria such as health and safety. DISCUSSION: If this chain of determinants has limits (linear nature, failure to consider the diversity of the determinants involved), it nevertheless provides a partial solution to the enigma of pesticide exposure situations. Indeed, the articulation between microscopic (treatment activities) and macroscopic (design and regulation) analysis turned out to be relevant to provide more information on the situations of pesticide exposure during the use of sprayers. The results of this study highlight the significance of considering changes at different levels. Considering the design and the regulation as transformation levers leads to a reflection upon the conditions to bring together so that different professional worlds, whether they are closely concerned by these issues or not, could collaborate and aim at a better prevention of pesticide exposure situations. CONCLUSIONS: This study highlight the role played by design and regulation, as macrodeterminants, in the emergence of pesticide exposure situations during the use of sprayers. By considering a wider environment than that of the work situation, the chain of determinants investigated makes it possible to consider changes at different levels in order to aim at a sustainable prevention.