We did not confirm the known association between benzene and AML, though this is likely explained by the strict regulation of benzene in Italy nearly three decades prior to study initiation. Our results support the association between benzene, xylene, and toluene and chronic lymphatic leukemia and between benzene and MM with longer latencies than have been observed for AML in other studies.

This study suggests that aromatic and chlorinated hydrocarbons are a risk factor for non-Hodgkin lymphomas, and provides preliminary evidence for an association between solvents and Hodgkin disease.

This paper considers Stochastic Shortest Path (SSP) problems in probabilistic networks. A variety of approaches have already been proposed in the literature. However, unlike in the deterministic case, they are related to distinct models, interpretations and applications. W e have chosen to look at the case where detours from the original path must be taken whenever the "first-choice" arc fails. The main results obtained include the proof of some counterintuitive facts (e.g., the SSP may contain a cycle), the proof of the validity of applying stochastic programming to this problem and the proof that the computational complexity of a particular SSP problem is polynomial.

Benzene was measured in blood and alveolar air of 168 men, aged 20-58 years, subdivided into four groups: blood donors, hospital staff, chemical workers occupationally exposed to benzene, and chemical workers not occupationally exposed to benzene. The group of exposed workers was employed in work places with a mean environmental exposure to benzene of 1.62 mg/M3 (8 hr TWA). Non-exposed workers were employed elsewhere in the same plant, with an environmental exposure to benzene lower than 0.1 mg/M3. Blood and alveolar air samples were collected in the morning, before the start of the work shift for the chemical workers. The group of exposed workers was found to be significantly different from the other three groups, both for blood and alveolar benzene concentrations. The mean blood benzene concentration was 789 ng/l in the exposed workers, 307 ng/l in the non-exposed workers, 332 ng/l in the hospital staff, and 196 ng/l in the blood donors. Apart from the exposed workers, blood benzene concentration was significantly higher in smokers than in non-smokers. The mean alveolar benzene concentration was 92 ng/l in the exposed workers, 42 ng/l in the non-exposed workers, 22 ng/l in the hospital staff, and 11 ng/l in the blood donors. Alveolar benzene concentration was significantly higher in smokers than in non-smokers in the groups of the hospital staff and non-exposed workers, but not in the blood donors and exposed workers. In the three groups without occupational exposure considered altogether, the alveolar benzene concentration correlated significantly with environmental benzene concentration measured at the moment of the individual examinations, both in the smokers (r = .636; p less than .001) and non-smokers (r = .628; p less than .001). In the same three groups and in the exposed workers, alveolar benzene concentration showed a significant correlation with the blood benzene concentration.

The findings of this study tend to support the role of organic solvents and certain chemicals in SSc causation. The association with teaching and working in the textile industry suggests that other exposures are involved in the aetiology of SSc among women. However, because of the small number of subjects, particularly in stratified analyses, chance cannot be ruled out as an explanation of some findings of this study.