Following a detailed report already published (Memorias do Instituto Oswaldo Cruz 45 (1), 123, 1947) on the frequency amd causes of industrial accidents in the Government printing plant (Imprensa Nacional), this publication deals with physical and chemical factors which can affect the health and comfort of the workers, in the new installations of said industry. Effective temperature determinations were carried out, in order to estimate the efficiency of ventilation systems employed, and the effects of adian; heat from the sun and internal heat sources upon physical environmental conditions. When such conditions were found to be unconfortable, improving uneasures were suggested. In a review of printing processes, due consideration is given to noxious agents which may set up local irritating or caustic effects as well as to those possibly responsible for acute or chronic general diseases. The A.A. give special consideration to potential sources of lead poisoning and thus some possible manifestations of saturnism were considered. In two random samples, one of 113 workers exposed, and another of 43 workers not exposed, to lead risks, the following signs and symptoms were investigated: Burton line, anorexia, nausea, metallic taste, constipation, epigastric pain, intestinal colic, pallor, insomnia, headache, tremor and extensor weakness of wrists. A significant difference, by the x² method, was found between the samples as a whole. On account of some workers being not able to give accurate informations, it was impossible to disclose whether all the observed signs and symptoms were indicative of actual or past intoxication. In another random sample including 74 of those 156 workers, lead determinations in urine were made by the Bambach and Burkey method, with Pulfrich Photometer, filter S 50 and 20 mm cell. This sample has been divided into three groups: a) 13 workers exposed to lead risk in I.N. and engaged in similar work outside the I.N.; b) 29 workers exposed only within the I.N. and c) workers not exposed.The mean values of lead elimination in urine (y per 100 ml) were 11.66, 7.74 and 5.20, respectively; the differences between the means of those small samples are statistically significant. However, as in groups a and b the safety limit established by Kehoe for a complete series was exceeded, additional precautionary measures seem to be indicated for the workers. Regarding the prevention of saturnism and other occupational diseases in I.N., individual and general measures are set forth in detail. At last, the A.A. point out the activities of a well organised industrial medical srvice and emphasise the importance of periodical medical examinations as a means of discovering individual susceptibilites to toxic or irritant substances and of detecting, in time, any slight harmfull effect upon the workers.