In 1919 the International Labour Conference at Washington requested the International Labour Office “to draw up a list of the principal processes to be considered as unhealthy”. But it was impossible in practice to draw up such a list, at least in a complete or final form, on account of the number and complexity of the operations which in some aspects could be considered unhealthy, the continuous evolution of industrial technique which does away with causes of disease in one direction, while giving rise to fresh possibilities of disease in another, and the indefinite character of the conception of “unhealthiness” which varies at different times and in different countries.

These considerations led to the idea of substituting for the list of unhealthy processes requested by the Conference, a sort of encyclopaedia which would analyse from the triple point of view of the work to be done, the worker employed, and the environment in which he worked, the various tasks involved in human labour, the properties of the substances dealt with, the operations involved in handling and working up these substances, the possible sources and carriers of intoxication and disease, the statistical data on the effects as far as known, the symptoms, the diagnosis, the therapeutic and prophylactic treatment, and the protective legislation already in existence.
It was a difficult task, and one which was bound to be open to the reproach of being neither complete nor final. But how could it be otherwise? No one can hope to fix once for all something which is living, evolving, progressive. Although, as was mentioned above, the evolution of technical practice in industry may create new dangers for the worker every day, yet the progress of this same technique and of industrial hygiene may, on the following day, do away with certain existing dangers, which must, notwithstanding, be recorded and analysed in this work. One of the virtues of this work is just the fact that it is not final. It seizes one moment in social life and in the progress of industrial hygiene, but it requires to be kept constantly up to date precisely because it is a scientific as well as a practical work.

This is its dual nature, as it is that of every piece of research undertaken by the International Labour Office, the strict purpose of which is to make science the servant of practical action. This Encyclopaedia is not a work of pure propaganda; it never sacrifices scientific objectivity to the ideas which the authors naturally have at heart. On the other hand, it is not purely a treatise on medicine or hygiene; it claims no originality in the treatment of the various questions; it does not claim to be an exhaustive study; on each subject it merely gives a summary of the existing position of science, with figures taken from statistics for the sake of example and not in support of any argument. It has tried to keep a middle path between a purely scientific work intended for the expert, and a popular manual. It is meant to supply workers, employers, their organisations, and practising doctors with the information necessary to enable them to discover, combat, and prevent occupational diseases, the economic consequences of which are as harmful to production as their social consequences are to the world of labour…

…The International Labour Office, in collaborating with these scientists for some years, has obtained a clearer consciousness of the scope of its mission. The Preamble to Part Xlll of the Peace Treaty [of Versailles] included among the urgent tasks of the Office the protection of workers “against sickness, disease and injury arising out of their employment”. The signatory States, in agreeing to this statement of principle, seem to have accepted the dictum of Beaconsfield that the health of the people is the most important of all problems. The Office has put at the disposal of those concerned a statement up to the actual position of science and has conveyed to the legislator the elements of physiology and physio-pathology necessary to him for setting up a code of industrial health; by collecting and concentrating this information in one work, and thereby increasing its range and appeal, the Office is continuing the work of those who, since the inception of “large-scale” industry, have endeavoured to protect human life, openly or insidiously menaced by new technical processes…

In ancient societies, dangerous and disagreeable tasks were reserved for criminals. Fourier, for all his fertile imagination, dared not foresee that the progress of industrial technique would one day lead to the suppression of unhealthy or dangerous occupations: he reserved filthy or dangerous work for his “small gangs”. Nowadays the problem is entirely different: the conscience of modern society realises that occupational diseases should not be reserved for certain persons, but that they should be made to disappear. The origins and the causes are now known, and all that is wanted is will and organisation. There are plenty of other sufferings and plenty of other infirmities to which mortals are exposed. As Puccinotti has said: “Life must be preserved for labour, and labour must be made harmless to life”. …

Albert Thomas
Director-General
International Labour Office
Geneva, 1930