Document aBa36RZebQ9yx6naRMbbZmjXR

RECOGNITION OF OCCUPATIONAL HEALTH HAZARDS PLAINTIFF'S EXHIBIT MON-2393 COURSE MANUAL VOLUME / LAM021570 U S.DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE Public Health Service Center for Disease Control NATIONAL INSTITUTE FOR OCCUPATIONAL SAFETY AND HEALTH Division of Training 6113 18266 B0C2320 MODULE Toxicity of Chemical Agents NO. 4 NOTES Formula INSTRUCTION The use of ppm only permits a comparison of gases with the same molecular weights. The relationship between ppm and mg/m3 is expressed by the following formula: ng/m^ x 24.7 at 25C and 760 ppm = molecular weight of gas mm of Hg Significance of size USA Europe Asbestos is exception. B. 2. Particulate concentration is expressed in number of particles per unit volume of air or mass per unit volume. For dusts which produce pneumoconiosis, it has been necessary to express dust concentra tions in particles per unit volume of air. How ever, since only those particles less than 5 microns in size have hygienic significance, the value relates to particles of this size and smaller unless otherwise specified. In the United States, dust concentrations may be expressed in million particles per cubic foot of air (25C and 760 mm of Hg). The unit is generally abbreviated as mppcf. In Europe, the preferred unit is particles per cubic centimeter or pcc. With new instrumenta tion and the development of different pathologic concepts, it is becoming customary to express pneumoconiosis-producing dust as mg/m^. In this case, however, specification of the size range is essential. When the term "total dust" is used, it refers to all airborne dust. The ex pression "respirable dust" means airborne dust less than 5 microns. Particulates, other than pneumoconiosis-producingj dusts are expressed in mg/m3 whether they exist as dusts, mists, or fumes. Asbestos is the exception to the above rule, as the standard nomenclature specifies number of fibres greater than 5 microns (longest dimension) per cubic centimeter of air. 4-6 LAM021571 6113 18267 ROC-321 1 1 1 1 I MODULE Pathology of Occupational Diseases NOTES INSTRUCTION NO. 5 Frame 33 Frame 33a(5) Frame 36 Frame 39 FRAME 33 Another serious lung disease Is asbestosls, caused by asbestos. In recent decades, scientists have determined that asbestos will also cause cancer of the lung and a rare form of cancer in the chest cavity mesothelomia. A combination of cigarette smoking and exposure to asbestos is especially dangerous, since the two factors contribute to the development of lung cancer. FRAME 33a(5). Not in the filmstrip. This shows a normal lung. It is a thin section of the lung, prepared by a procedure known as the Gough technique, after its developer. FRAME 36 This is a lung section of a coal miner-- the pathology is due to a disease known as coal workers' pneumoconiosis. Compare this to the preceding slide. FRAME 39 Organic dusts also cause lung changes. These are reversible changes, as compared to irreversible changes due to mineral dust. One is a worker with bagassosis from the dust of moldy bagasse - the residue of sugar cane. The other is farmer's lung, the result of inhaling moldy hay. The changes in this film are due to numerous fungal spores and result in a low-grade inflammatory response. 5-6 LAM021572 6113 18268 B0G~322 1 MODULE Pneumoconiosis NO. 12 1 NOTES INS T R UCTION 1 Non-disabling pneumoconiosis Classification of the various pneumoconioses Visual 12 -1 silicates, calcined diatomaceous earths, coal dust, and beryllium. 1 C.2. Other dusts may cause a non disabling pneumoconiosis. Non-disabling or benign pneumoconiosis is produced by physiologically inert dusts. The condition is apparent on a chest X-ray, especially when the dust is radiopaque. Inert dusts do not have predisposing effects on tuberculosis or other infections and do not cause impaired lung function. Included in the inert dusts of industrial significance are carbon (except coal), calcium compounds (such as cement, marble, and gypsum), iron dust and fume, artificial abrasives (such as carborundum, emery, and aluminum oxide), and other metals, such as barium and tin. Because of their radiopaque properties, iron, barium, and tin produce distinctive patterns on a chest X-ray. '1 C.3. The various kinds of pneumoconiosis are classified according to their causative agent. Because the term "pneumoconiosis" is non specific, most forms of the disease have a precise designation which relates to the causative agent. For example, silicosis is a pneumoconiosis caused by silica dust. Other examples include asbestosis (asbestos), talcosis (talc), diatomaceous earth pneumoconiosis, and coal pneumoconiosis. Visual 12-1 gives a more detailed listing of the types of pneumoconiosis and whether they are disabling or benign. 12-6 LAM021573 6113 18269 BOG-323 I 1 MODULE Pneumoconiosis NOTES INSTRUCTION NO. 12 Role of tuberculosis Coal mine dust Asbestos Until recent years, tuberculosis was a common complication of silicosis, and it was believed by many investigators that the tubercle bacillus had a role in the etiology of silicosis. However, with the decline of tuberculosis in the general population, it is observed much less frequently in silicotic patients. Tuberculosis is now generally accepted as being a possible complication of silicosis, as well as of other pneumoconioses, but with no specific etiologic role. Coal mine dust produces a disease similar in many respects to silicosis. From its appearance on an X-ray film, a radiologist would have difficulty in distinguishing between the two diseases. Pathologically, however, the two forms of pneumoconiosis are quite different. An infectious process other than tuberculosis appears to be an essential feature of coal pneumoconiosis. In its complicated form, huge areas of lung cavitation occur, which prevents the lungs from performing their physiologic function. Many investigators believe that silic^ plays an essential role in the disease process, while others regard it as having little significance. One major fact which supports the silica theory is the greater incidence and severity of the disease in anthracite coal workers. Anthracite coal contains significantly higher percentages of silica. Asbestos is one of the few silicates (SiO^) which causes a disabling pneumoconiosis. The pathologic action probably results from irritation of the lung tissue by the asbestos particle, since collegen formation is not characteristic of asbestosis. In recent years asbestos has also been implicated as a cause of lung cancer and mesotheliomia, a rare form of cancer of the pleural lining of the chest wall. Although silica and coal dusts have been suspected by some investigators as being causes of lung cancer, there is little evidence to support this concept. 12 - 10 LAM021574 6113 18270 1 1 1 1 1 1 1 1 1 1 :i :i i :i -j