Document NeoMXRKrRqvp2rVpGbK4pQB6b

American Journal of Industrial Medicine 14:657-659 (1988) 658 Nilsson et ai. was loaded approximately once a month. The rest of the time. the ship transported mainly light petroleum products such as gasoline and jet fuel and occasionally methanol and formalin. CASE 2 A 41-year-old man, who had reported no previous illnesses other than throat infections. had repeated cutaneous infections followed by pneumonia in early 1985. Acute myelomonocytic leukemia (M4) with a high leukocyte count (170 X lO'/liter) was diagnosed in mid-1985. The patient has been treated successfully with cytostatic drugs followed by a bone-marrow transplantation. Between 1958 and 1964, he worked as a seaman, mainly on tankers canying petroleurn products and solvents. Tank-cleaning operations were frequently part of his job. During this time, there was an incident of high exposure to trichloroethylene. From 1965 to 197I. he was a house painter and thus exposed to organic solvents such as thinner and white spirit, but probably not to benzene. In 1972 he became a deck officer on coastal tankers that carry mainly petroleum products such as gasoline. and in 1977 he began working on tankers that periodically transpon pure benzene and refinery waste products with a high benzene content. Since 1978 he has been shipmaster and has only rare involvement in loading and tank-cleaning operations. Before 1980 all capacity gauging was done manually. DISCUSSION The cytological diagnoses and exposure histories of these two men indicate that these cases of leukemia may have been caused by exposure to benzene during their work as deck officers. As far as is known. there have been no epidemiological studies of the incidence of leukemia and other types of cancer in seamen working on tankers. According to several reports, there is an increased risk of developing leukemia of the acute. nonlymphatic type, even if exposure to benzene is low or moderate [Yin et a].. 1987; Aksoy, 1985: Infante and White, 19851. Both patients described here were exposed to benzene as deck officers on coastal tankers carrying pure benzene and other petroleum products. Light petroleum products such as gasoline usually contain '-5% benzene and also may have contributed substantially to benzene exposure. Other types of pj*rolysis products from refineries also may have a high benzene content. These men also had been exposed to high concentration: of vapors from petroleum products such as aliphatic and aromatic hydrocarbons and vapors from other solvents. such as trichlorethylene and styrene. A s chief officers, these two men had been responsible for loading and tankcleanins operations. Most of the ships they had been working on were not equip`pd with automatic cargo level indicators, which means that the men were heavily exposed to cargo vapors escaping from manholes. Especially during the final phase of the loading. the "top-off." which takes 5 to 20 minutes for each tank, exposure to benzene may have been very high. Measurements have shown concentrations of up to several hundred parts per million (ppm) during "top-off" of gasoline, according to investigations carried out in Sweden, Norway, and the United States [Mowe et a]., 1977: Astleford et al., 1982; Gjorloff et ai., 1982; Holmberg and Lundberg, 1985; Nordlinder and Ramniis. 19871. On coastal tankers. cargo is loaded into several Nodymphatic Leukemia in Workers on Coastal Tankers 659 tanks, usually 10 to 30, each of which has to be topped off individually. The whole loading process usually takes between 5 and 10 hours and may be repeated two or three times weekly, which could indicate that these deck officers were exposed to some hundred ppm of benzene for several hours per week during cenain periods. Although exposum 10 benzene is highly variable in merchant seamen, some groups may be exposed to significant doses and have an increased risk of developing leukemia. Today some tankers are equipped with automatic loading surveillance systems, but the cargo-level indicators are not always reliable, and open gauging during topsff is often performed on such ships. Until ail ships are equipped with reliable closed loading syStems, it is imponant that the crews be kept aware of the risks and that they use protective equipment when necessary. REFERENCES Aksoy M (1985): Benzene a leukemogenic and carcinogenic agent. Am J Ind Med 8:9-20. Astlcford WJ. Bass RL. Buchingham JC. Magott RJ (1982): "A Crew ExposureStudy." Phase I Volume 111. "At sea." San Antonio. Texas: Southwest Research Institute. Cronkite EP ( 1987): Chemical leukemogenesis: Benzene as a model. Scmin Hematol 24:2-11. Gjorioff K. SWdin B. Svtdung 1 (1982): "ArbctsmiljoforhAllandcn vid lastning av peirokemiska produkter i tankfartyg." Fvksta: lnstitutet for Vatten och Luftvbd. B 653. (In Swedish). Holmbeq B. Lundberg P (1985): Benzene: Standards, occurrence. and exposure. Am J Ind Med 7:375 -383. Infante PF. Wagoner JK. Rinsky RA. Young RJ (1977): Leukaemia in benzene worken. Lancet 9:76-78. lnfante PF. White MC (198% Rejections of leukemia risk associated with occupational exp0sc.t to b e n n e . Am J Ind Mtd 7:403-413. Mowi G.Simonsen 0. Weimundscn B (1977): "Sjiifolk i kjemikaliefan." Hovedprojcktet. Dei 11. Oslo: Yrkeshygieniskt Institutt. (In Norwegian). Nordlinder R. Ramnb 0 ( 1987): Exposure to benzene at different work places in Sweden. Ann &cup Hyg 31:345-355. Tsongas TA (1985): OccUpatiOnal factors in the epidemiology of chemically induced lymphoid and hemopoietic cancers. In: Doll R (ed):"Toxicology of the Blood and Bone Marrow.'' New York: Irons. Raven Pmss. Yin SN,Li GL.Tain FD. F U n.Jin C.Chen YJ. Lou SJ.Ye PZ. Zhang JZ.Wang GC. Zhang XC. Wu HN. Zhong QC ( 1987): Leukmnia in benzene worken:A retrospective cohon study. Br J Ind Med 44: I 24- I28.