"Industrial hygiene, as the implementation of a set of preventive techniques and behaviors, is a complex and non-linear process in which manufacturers, engineers, hygienists, and workers are involved with each group being moved by its own logic. The case of the French Crystal Factory of Baccarat during the second half of the nineteenth century clearly portrays the dialectics between technical progress, hygiene, and economic logic that come to play in the realization of industrial hygiene. The situation was very surprising in comparison with other descriptions well known to historians: manufacturers anxious about the hygiene of workshops; good health of workers despite their very hazardous occupations; parallel improvement of both technical and sanitary situations whereas the economic pressure in the glasswork sector was growing. The Crystal Factory of Baccarat is a rare and atypical firm. Nevertheless, its study is very useful in order to understand other similar or different situations."