Some workers are exposed to products potentially harmful to their health. For a better understanding of the relationship between these situations and the diseases that can arise, in some cases it may be useful or even necessary to use exposure, effect or susceptibility bioindicators. The use of bioindicators raises ethical questions. The authors of this publication wanted to better understand the context of this practice, as perceived by various groups engaged in occupational health. Starting with the results obtained, they defined "ethical traps", namely aspects that must receive particular attention during the ethical reflection inherent in the use of occupational health bioindicators.