Abstract The risks related to the interaction between plastic moulding machines and their peripheral equipment (e.g., robots, conveyors) are not well known by the people in this industrial community and these risks can sometimes lead to fatal occupational accidents. The aim of this research project is to study the safety of workers using horizontal plastic moulding machines with peripheral equipment. Its objective is to evaluate the safety of the people working in the moulding zone of this type of moulding machine, by identifying the risks and analyzing the means of risk reduction for maintenance and production tasks. An analysis of the CSST's intervention and accident reports (depersonalized), and the consultation of standards and guides on this subject provided an understanding of the risks to which the users of these machines are exposed. These documents offered up-to-date knowledge about the current good risk-reduction practices. Also, eight plant visits made it possible to observe workers during maintenance and production work. The observed maintenance work involved moulding machine maintenance: mould polishing and mould cleaning. Production work involved insert installation, mould changes, production tests, and operational tests (production of moulded parts). The noted risks in the plants and the observed means of risk reduction were documented. Analysis of the observed means of risk reduction identified the strong points, as well as aspects requiring improvement. These observations also allowed the characterization of the workers' intervention practices to ensure their safety during maintenance and production in the mould zone of this type of moulding machine. Three characteristic risk-reduction measures were identified: Use of a "padlock-partial lockout" procedure: a padlock is applied to the console or to a guard to avoid start-up by a third party; Use of safety functions: the workers have total confidence in the moulding machine's control system and its peripheral equipment for ensuring their safety. To access the mould zone, they open the locked out or interlocked mobile guards, use pressure-sensitive floors detecting any presence in the mould zones, and use the emergency stop function; Inspection: before entering the mould zone, they verify that the means of protection installed on the machines is operating properly, and before using hoisting equipment to handle the mould, they check the condition of the hoisting equipment. No lockout according to the meaning in the Québec Regulation respecting occupational health and safety was observed. According to the participants met during the visits, this lockout is applied only for major maintenance or repair work. Furthermore, the observations of major use of the safety functions during interventions in the mould zone prompted the research team to question the participants about the reliability of these safety functions and about the integration of the peripheral equipment's control system into that of the moulding machine. The integrators who were met emphasized the difficulties that they encounter in evaluating this reliability: insufficient knowledge about the standards in force, for example. To enlighten them, an example of an a posteriori evaluation of a safety function is proposed in this report for studying the feasibility of such a procedure and for identifying its difficulties and limitations.