The respirator was never approved for lead fumes, but the marketing information omitted this information.

Cleerence End pley .0003 .oo4 High lead babbitt .... . ...' ..0013. p........................... .012 Shiffl fpBfr-iolId, Jaminato,d_o_r__m_o_n_o_ ...

There is an abundance of oils such as linseed and soya, but pigments, including lead, zinc, titanium and certain colors, are in shorter supply.

It is b ecau se of th ese d evelop m en ts, no doubt, th at th e in ciden ce of lead poison in g am on g ch ild ren in Cin cin n ati (as w ell a s in Baltim o r e) ap p e ar s to be m uch h igh er th an it i s in m o st c it ie s, i.o . th e d iagn ostic tech rdque, to w h ich p e d iat r ic ia n s h ave been ale r t e d in th is m ed ical ce n t e r , is su ch th at c a se fin d in g, w h ile n ot en tir ely ce r t ain , h as been gr e at ly im p roved .

Prevention is the only positive means of attack on silicosis With modern engineering technics there is no reason why silica exposures cannot be reduced to safe concentrations and silicosis completely eliminated in the course of a few years Until that time comes all persons working in such atmospheres should be examined clinically and radiologically at frequent intervals by a competent physician Those with silicosis should be protected from further exposure to silica dust Persons with tuberculous lesions should not be employed Measures for the prevention of exposure to dusts and fumes including silica dust are discussed under prevention of occupational diseases due to chemical substances on pages 1086 to 1091 ASBESTOSIS Asbestosis is a pneumoconiosis due to the inhalation of asbestos dust Nature of Asbestos Asbestos is a general term which is applied to minerals of fibrous form These minerals are silicates of varying composition which fall into of wi invol of ex I the c bestc _ fiber tured inclu . ated A there incre ated cases expo 1 dust THE DUSTS 1051 two distinct groups serpentine and amphibole Chrysotile a hydrous magnesium silicate of the serpentine type is by far the most common type of asbestos The amphibole group includes various silicates of iron calcium magnesium and in some cases sodium examples are crocidolite and tremolite Asbestos fibers are usually from 20 to 500 microns in length and from 0.5 to 50 microns in diameter The fibers of crocidolite are much stiffer and straighter than those of chrysotile Reaction of Tissues to Asbestos Pulmonary fibrosis results in man and in some animals from the inhalation of chrysotile the serpentine type of asbestos This fibrosis differs from that which occurs in silicosis being a fine interstitial diffuse fibrosis around the terminal bronchioles rather than nodulation It is believed that fibers up to 200 microns in length can penetrate the respiratory tract if the maximum diameter does not exceed 5 microns Fibers which are inhaled accumu- late in the lumen of the respiratory bronchioles and later in the alveolar ducts but do not seem to penetrate to the alveoli Itis generally believed that the fibrosisis due to the mechanical irritation of the long fibers between 20 and 50 microns in length Presumably the motion of the lung tissue in breathing combined with the filamented structure and the flexibility of the fibers are responsible for this irritating effect This theory is supported by the fact that asbestos fibers unlike silica dust are inactive when in contact with other tissues such as the liver where there is no mobility and by the fact that they do not cause pulmonary fibrosis if the fibers are short or are ground to small particle size The stiff straight fibers of crocidolite do not stay in the walls of the bronchioles but pass on into the alveoli and do not appear to cause fibrosis Fibrosis occurs only where there is mechanical rubbing of the tissue against the fibers Aluminium whichis effective in preventing the action of silica dust is not effectivein preventing asbestosis Clinical Aspects The clinical symptoms are due to the fibrosis and the con- comitant pathological changes chiefly emphysema and bronchiectasis Progressive dyspnea which can lead to disablement is the chief symptom Cough and loss of weight also occur Death is due to secondary respiratory infection or to cardiac involvement It is generally believed that the fibrosis will not progress after cessation of exposure Diagnosis of asbestosis must rest on a history of exposure to asbestos dust on the clinical symptoms and on the radiological examination The presence of as- bestosis bodies in the sputum is not of any diagnostic value Asbestosis bodies are fibers which are surrounded by an containing coating and which have . frac- tured to give peculiar structures They may be formed from any fibrous material including asbestos but are neither indicative of the degree of exposure nor associ- _ ated with the fibrosis Although some cases of tuberculosis have been reported in asbestos workers there is no convincing evidence either clinical or experimental that asbestosis increases susceptibility to tuberculous infection A few cases of lung cancer associ- ated with asbestosis have been found in various autopsy studies Whether these cases are only chance occurrences or exposure has not been proven as yet whether are they Thereis no known treatment for asbestosis prevention dust is the only effective weapon against this condition related to the of exposure to asbestos asbestos 4 i \ \ F By f {} fi H| i i t; i ; Ta 1052 OCCUPATIONAL DISEASES Incidence of Asbestosis The incidence of asbestosis in persons working in environments containing asbestos dust varies with the extent and duration of ex- posure The disease does not usually appear until after 5 to 10 years of exposure The incidence of asbestosis increases progressively with the duration of exposure More than half of the workers with 20 years of exposure have the disease Studies | in asbestos industries indicated that 5,000,000 particles per cubic foot of air is the maximum safe concentration but recent work suggests that the standards may vary with the percentage of long particles in the dust OTHER HARD ROCK AND MINERAL DUSTS Siderosis Exposure to iron oxide produces a benign pneumoconiosis called siderosis By itself this mineral provokes no significant fibrosis but merely pigmentation which has no influence on pulmonary function Gardner 1940 However roentgenograms of workers exposed to the iron oxide dust show nodular shadows simulating those of silicosis Clinical studies of these workers autopsy findings in cases where death resulted from other causes and animal experimentation have proven that these shadows are not due to fibrosis but to the opaque iron oxide which had accumulated in foci throughout the lungs Studies on animals indicate that iron oxide dust does not cause fibrosis or affect the course of experimentally induced tuberculosis The inhalation and deposition of tin oxide in the lungs may also produce similar pseudonodulation in the roentgenograms Anthracosis Coal dust in the absence of free silica has been considered to produce only a benign type of pneumoconiosis Recent observations have indicated that some lung changes may result from exposure to certain types of coal dust The significance of these findings cannot be evaluated at present DUSTS OF PLANT ORIGIN General Effects Public health officials are often asked if grain wood cotton and other dusts of plant origin produce any harmful effects on the lungs or other tissues In general it can be said that these natural organic dusts may cause allergic reactions in susceptible persons leading to a variety of conditionsin the respiratory tract skin or other tissues and that many of these are irritating to the respiratory tract and skin even when no allergic reactions are visible In some cases the effects are due to the smuts mites fungi or other parasites which contaminate these dusts In other cases the irritation is due to the physical rather than to the chemical properties of the dust Many natur

Around midyear the sale of the White Lead business at Scranton was negotiated and finally conaunated early in June.

This filter "takes out seven times more nico tine and tars than any other leading filter cigarette."

("Dumont") and The Bus ton Lead Company/ Inc., a wholly owned subsidiary of Dumont ("Buston") and The Glidden Company ("Glidden").

Bcnzcnc and chlorine are passed into vc.iscls callcd " photo- chlorinators", in which, under thc action of light. chlorine is added to the bcnzcne niolcculc with thc ~,xmopoictic orgnn5 which, in constitutionally prcdisposcd suhjcctc. may lead to the development 14'truc Icukamia.

per und rinc lead to regressive changes in the gut diverticula and damage to the stomach wall.

The decontrol of lead and the increased production for one of our good customers will insure one of the best years for our Euston Lead plant at Scranton, Pa.

(e) Defendant objects to this interrogatory as it - is irrelevant and not likely to lead to the discovery of admiss ible evidence.

This, of course, considerably complicates the problem of control, because once the carcinogens escape from the unit, thev may contaminate everything in a room, or even a whole building, leading to subsequent skin absorption in those who hrusli again.-.!

Around midyear the sale of the White Lead business at Scranton was negotiated and finally conaunated early in June.

Progressive dyspnea, which can lead to disablement, is the chief symptom.