Document mBnbkryEZr39kOJpZ28ba3bQ

90 OCCUPATIONAL TUMORS AND ALLIED DISEASES dated properly, if consideration is given to the fact that actually only 8 to io per cent of the men employed in such operations are markedly exposed to this agent (Teutschlaender). The statement of Leymann that io cases of pitch cancer, in addition to numerous precancerous pitch warts, had been recorded among 2,500 men working in 65 hard coal briquette plants in Prussia, must be evaluated in the light of this information. Downing listed the following incidence of pitch papilloma and cancer among the various groups of patent fuel workers: Occupation Heatermen Pitch Wheelers Loaders and Fuel Stowers Laborers and Tippers Ovenmen Millmen, Grinders Block Regulators Pressmen Roperunners Hostlers Total Number of Papillomas 11 23 20 7 5 3 1 1 1 1 73 Number of Men Employed 9 54 36 35 7 18 4 6 3 2 x74 The incidence of pitch papillomas is greatest, according to Downing, among heatermen, pitch wheelers and fuel stowers. Downing declared that small traumatic injuries produced by flying pieces of pitch as well as marked perspiration induced by the handling of hot briquettes (pitch being soluble in sweat) intensified the action of pitch and aided in the development of the neoplastic response. Sladden (1928) reported that in the Swansea district, where about 900 men are employed in the patent fuel industry, there were 13 cases of epithelio mas in 1920 and 1925, while 5 cases per year were found on the average during the intervening 4 years. Commenting on these figures, Sladden emphasized the fact that the incidence of pitch cancer in the various briquette plants depended upon several factors and, thus, was not uniform. Factors influencing the cancer rate are, according to Sladden, number and age of men employed, duration of employment, continuity of exposure, degree of exposure, character of pitch used, degree of attention paid to preventive and precautionary technical as well as sanitary measures, and periodical medical examinations. Sladden found among 200 patent fuel workers, 150 of tvhom came for their routine medical examination, while 50 came to the hospital because of some skin lesion, evidence of pitch skin in 50 per cent of the first