[Industrial health: how not to lose your life while earning it]

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[Possibilities and limits in roentgenographic documentation of lung lesions particularly in pneumoconiosis (author's transl)]

Roentgenographic appearance of minimal pneumoconiosis has changed with reduction of dust exposure. This urges radiologists to reconsider the evaluation of follow-up chest films. The possibilities of high-kilovoltage technique offer standardized and possibly stabilized conditions. Information about technical exposure data, chest x-ray equipment, and the generator are mandatory for film reading.

[Problems and experiences with computerized coding of radiological findings in pneumoconioses (author's transl)]

For medical surveillance of dust workers, correlation of anatomical and radiological findings in silicosis and asbestosis is an assumption for computerized application of the ILO U/C 1971 classification of pneumoconiosis. The new regulations of insurance companies for preventive examinations in workers exposed to asbestos are described, and their results presented. Practicability and preliminary data suggest important information for the future.

Steady state respiratory responses to tasks used in Federal testing of self-contained breathing apparatus

A portion of Title 30, Part II, CFR calls for a Man Test, which is a series of regimens performed with a breathing apparatus. The respiratory responses to the tasks in the Man Test were established on coal miners and students. Based on these responses, the minimal metabolic requirements were derived for the use of breathing apparatuses with a service life of 30 minutes or more.

Control of cobalt exposures during wet process tungsten carbide grinding

Pneumoconiosis has been reported in tungsten carbide manufacture; past studies have suggested that adverse cobalt exposures may occur from wet process tungsten carbide grinding. This study shows that wet process tungsten carbide grinding without local exhaust can cause adverse cobalt exposures. Controls are summarized.

Effect of the 2.0 mg/m3 coal mine dust standard on underground environmental dust levels

The 1969 Federal Coal Mine Health and Safety Act established environmental dust standards for underground coal mines. The Act requires that the average concentration of respirable dust in the active workings of a mine be maintained at or below 3.0 mg/m3; and, that effective December 30, 1972, the 3.0 mg/m3 standard be reduced to 2.0 mg/m3. This paper discusses the current status of dust levels in our underground coal mines, the effect of the 2.0 mg/m3 standard on underground dust levels, and associates the current levels with specific operations and occupations. The comparison is made between current levels and those existing prior to December 30, 1972.

Preprocessing cotton to prevent byssinosis

Merchant, J. A., Lumsden, J. C., Kilburn, K. H., Germino, V. H., Hamilton, J. D., Lynn, W. S., Byrd, H., and Baucom, D. (1973).British Journal of Industrial Medicine,30, 237-247. Preprocessing cotton to prevent byssinosis. A fundamental approach of cleaning or deactivating cotton prior to manufacturing has long been advocated to prevent byssinosis, but no trial had been conducted to test the feasibility of such an approach. In the study described, it was possible to be directed by both biological observations and the results of manufacturing trials. An exposure chamber was built in a cotton textile mill which had been previously studied as part of a large cross-sectional survey. The chamber was provided with an independent air conditioning system and a carding machine which served as a dust generator. Sixteen subjects, who had shown reductions in expiratory flow rate with exposure to cotton dust, were chosen to form a panel for exposure to raw cottons and cottons which had been preprocessed by heating, washing, and steaming. Indicators of effects were symptoms of chest tightness and/or dyspnoea, change in FEV_1·0, and fine dust levels over 6 hours of exposure. Exposure of the panel to no cotton dust resulted in no change in FEV_1·0 and served as the control for subsequent trials. Exposure to strict middling cotton resulted in a byssinosis symptom prevalence of 22%, a significant decrement in FEV_1·0 of 2·9%, and a fine dust level of 0·26 mg/m³. Exposure to strict low middling cotton resulted in a byssinosis symptom prevalence of 79%, a decrement in FEV_1·0 of 8·5%, and a fine dust level of 0·89 mg/m³. Oven heating strict low middling cotton resulted in a byssinosis symptom prevalence of 56% and a relatively greater drop in FEV_1·0 of 8·3% for 0·48 mg/m³ of fine dust. Washing the strict low grade cotton eliminated detectable biological effects with a symptom prevalence of 8%, an increase of 1·4% in FEV_1·, and a dust level of 0·16 mg/m³, but the cotton proved to be difficult to process. As an alternative method, strict low middling cotton was steamed initially in large dyeing vats, on a conveyor, in an autoclave, and in a modified yarn dyeing apparatus or `pipe' steamer. Of these methods, autoclaving cotton was the most successful, reducing symptom prevalence to 8%, the drop in FEV<sub>1·0</sub> to 0·4%, and the dust level to 0·23 mg/m<sup>3</sup>. Development of a high capacity cotton steamer based on the small `pipe' steaming model resulted in a symptom prevalence of 8%, a decrement in FEV_1·0 of 0·8%, and a mean dust level of 0·27 mg/m³. Regressions calculated from raw and high capacity steaming trials indicate that at low dust levels steamed cotton dust was roughly one half as biologically active as raw cotton dust.