Butadiene cancer exposure-response modeling: based on workers in the styrene-butadiene-rubber industry: total leukemia, acute myelogenous leukemia, chronic lymphocytic leukemia, and chronic myelogenous leukemia.

Cox regression is used to estimate exposure-response models (with cumulative 1,3-butadiene (BD) ppm-years as the exposure metric) based on the most recent data and validated exposure estimates from UAB's study of North American workers in the styrene-butadiene-rubber industry. These data are substantially updated from those in USEPA's 2002 risk assessment. The slope for cumulative BD ppm-years is not statistically significantly different than zero for CML, AML, or, when any one of eight exposure covariates is added to the model, for all leukemias combined (total leukemia). For total leukemia, the EC(1/100,000) is approximately 0.15 BD environmental ppm and the corresponding unit risk factor is approximately 0.00007 per BD environmental ppm. The excess risk for CML is approximately 15-fold less than for total leukemia. The maximum likelihood estimates suggest that there is no excess risk for AML from cumulative BD ppm-years. For CLL, the slope is statistically significantly different than zero. The excess risk for CLL is approximately 2.5-fold less than for total leukemia. For both total leukemia and CLL, the slope is not statistically significantly different than zero when the exposure-response modeling is based on the person-years with cumulative BD ppm-years less than or equal to 300 ppm-years.

[Hyperbaric oxygenation in inhalation poisoning with substances with varying mechanisms of action (styrene, toluene and carbon monoxide]. / Giperbaricheskaia oksigenatsiia pri ingaliatsionnoi intoksikatsii veshchestvami s razlichnym mekhanizmom deistviia (stirol, toluol i oksid ugleroda]

The disintoxicating mechanisms of hyperbaric oxygenation (HBO) on inhalation intoxication with substances from different chemical classes (aromatic hydrocarbons and carbon oxide) were investigated in rats. HBO was demonstrated to have a significant effect on the whole array of the studied parameters (physiological, morphological, and biochemical ones), on lipid peroxidation (LP) in particular. The levels of LP products in the liver, brain, blood became normal and the antioxidative system was stimulated as well. The most striking effect of HBO therapy on inhalation of toxic agents taken in the mean or maximum lethal concentrations was noted in the use of carbon oxide.

Lymphohematopoietic cancers and butadiene and styrene exposure in synthetic rubber manufacture.

The described nested case-control study of lymphohematopoietic cancers occurring in a cohort of synthetic rubber production workers was conducted to determine the associations of these cancers with exposure to butadiene and styrene. Cases have been confirmed through hospital record review of 95 percent of the cancers. Exposures are based on measured values of the two chemicals from personal monitoring data in seven of the eight plants under study. The results indicate that the risk of leukemia increases with exposure to a time-weighted average butadiene measure. The odds ratio at only 1 ppm average butadiene exposure is 1.50 (95% CI 1.07, 2.10). Work in specific areas also contributes to the risk, possibly because these areas have not been completely characterized for differences in butadiene exposure. Hodgkins disease is also associated with butadiene exposure. Multiple myeloma, lymphosarcoma, and all lymphomas are associated with exposure to styrene. Since workers in this industry are apparently exposed to two carcinogenic agents, further effort must be made to distinguish the exposures to each chemical over time and to characterize their interrelationship with the risk of cancers of the lymphohematopoietic system.

The applicability of the measurement of urinary thioethers. A study of humans exposed to styrene during diet standardization.

The excretion of thioethers was measured in the urine of 6 volunteers, who were experimentally exposed to styrene, and 18 styrene workers. In addition, 12 clerks (non-smokers) and 12 sheet-metal workers (smokers) served as control groups. Diet was standardized during the experiments. Thioethers were measured by a spectrophotometric method. The volunteers were exposed to styrene, 210 mg/m3, for 2h at a 50-W workload. An increase in thioether excretion was observed; the largest was in the urine samples collected between 0.5 and 5 h after the end of the exposure. After 43 h the excretion of thioethers was close to the pre-exposure level (3.5 mmol/mol creatinine). About 1% of the styrene absorbed was detected as thioethers in urine, which is only about 1/10 of the conversion reported for rats. From excretion rate curves a half-life of about 11 h was calculated for styrene thioethers. The styrene workers were employed at two plants. The average exposure to styrene (time-weighted average 8 h) was estimated to be about 115 mg/m3 (smokers in plant A), 55 mg/m3 (non-smokers in plant A) and less than or equal to 10 mg/m3 (non-smokers in plant B). The excretion of thioethers in exposed workers at plant A was higher by 2-4 mmol/mol creatinine than that in non-exposed controls. In plant B, where exposure was lower, an increase in that amount of thioethers excreted in the urine by exposed workers was less pronounced, and was statistically significant only when post-shift samples were compared with pre-shift samples.(ABSTRACT TRUNCATED AT 250 WORDS)

Psychosis following styrene exposure: a case report of neuropsychological sequelae.

A patient with a significant history of substance abuse was exposed to styrene and other solvents in the workplace. He became acutely psychotic, experiencing visual hallucinations. The psychosis was controlled with neuroleptic medications and avoidance of solvent exposure, but he continued to show significant deficits in visual-spatial and memory abilities. These deficits cleared with time away from the workplace. The case is of interest in terms of neuropsychological sequelae of solvent exposure and potential interaction of solvents with alcohol and recreational drugs.

Hematological findings among styrene-exposed workers in the reinforced plastics industry.

A cross-sectional survey of hematological parameters was carried out among 221 workers exposed to styrene in the reinforced plastics industry and 104 controls. Styrene exposure was assessed in both groups by monitoring urinary excretion of styrene metabolites (i.e. mandelic and phenylglyoxylic acids) in post-shift urinary samples collected over five consecutive days. Blood tests were performed with the same counter for all subjects. Information on factors liable to affect hematological parameters was collected from personal questionnaires completed by the workers. Urinary excretion of styrene metabolites varied from 15 to 3740 mg/g creatinine. Exposed subjects exhibited significantly lower mean values of neutrophils and mean corpuscular hemoglobin concentration (MCHC) than controls, and significantly higher mean values for monocytes and mean corpuscular volume. A dose-effect relationship was found for MCHC which decreased with urinary metabolite concentrations. These results remained statistically significant for all parameters after adjustment for age, sex, tobacco and alcohol consumption, place of residence (rural or urban) and time of blood sampling (morning or afternoon) with the exception of neutrophils whose relationship with exposure was essentially explained by smoking. These results are suggestive of a direct effect of styrene-exposure--in the range considered--on the statistical distribution of some hematological parameters.

[The effects of inhalation of styrene on the neurobehavior in the offsprings].

Pregnant Wistar rats were exposed to 0.60 +/- 18.9, 297.7 +/- 72.4 ppm styrene for 6 hours/day during 7 to 21 days of gestation. No significant differences among groups were found in the length of gestation or in the number of offspring delivered. Several neurobehavioral tests detected differences in the offspring exposed to styrene during gestation from controls. Even exposure to relatively low concentrations of styrene delayed some physiological developments, in addition to causing disturbances of the neuromotor coordination function (Rota-Rod performance) and learning acquisition (CRF). Furthermore, large dose led to subtle changes in emotional behavior and increases in spontaneous activities in addition to the delay of neurobehavioral developments.

Occupational asthma due to styrene: two case reports.

Two cases of occupational asthma due to styrene are described. The subjects complained of cough, breathlessness, and symptoms of asthma when coming into contact with styrene; in patient 1 the respiratory reaction was followed by a late cutaneous rash. The symptoms disappeared when the subjects were away from work on weekends or holidays. In both cases, inhalation challenge with styrene produced an immediate bronchospastic reaction which was followed by a late cutaneous rash in patient 1. Prior administration of disodium cromoglycate (40 mg from a spinhaler) prevented the respiratory reactions completely, but failed to prevent the late skin response in case 1. Styrene removal was followed by complete disappearance of the symptoms. We conclude that styrene can be a primary cause of occupational asthma.

Mortality of styrene production, polymerization and processing workers at a site in northwest England.

The mortality of 622 men who worked for at least one year in the production, polymerization, and processing of styrene at a chemical site in the United Kingdom during the period 1945-1974 was surveyed up to the end of 1978; 3 072 male manual workers at the same site but unexposed to styrene were also studied. A statistically significant excess of lymphoma deaths was found in the exposed population, and two of the three deaths observed occurred in men less than 40 years of age. The small number of deaths and the lack of any evidence for an association with duration or level of exposure to styrene are reasons for interpreting this result cautiously. However, the otherwise normal pattern of mortality in the exposed population and the absence of any excess of lymphomas in the reference group lend some support to suggestions that exposure to styrene may be associated with lymphomas in man. An analysis of cancer registrations for the exposed population revealed no further cases of lymphoma but identified one case of lymphatic leukemia. An excess of laryngeal cancer registrations was found. As this effect has not been previously postulated and because of the small number of registrations, too much weight should not be attached to this one observation.

Some behavioral effects of early styrene intoxication in experimental animals.

Male albino rats were administered styrene in groundnut oil, PO at doses of 100 mg and 200 mg/kg body weight daily for 14 consecutive days. No neurological deficit was observed in any animal during the course of the experiment. Mean % avoidance response (learning) for each treated group, from day 1 to day 4 of conditioned avoidance response training, revealed a general increase. Styrene significantly increased the % avoidance response at both doses as compared to controls, although no definite dose-response relationship was evident. No significant difference was noted in the spontaneous locomotor activity and regional brain catecholamine levels, between controls and treated rats of either dose. Serotonin levels in hippocampus, hypothalamus, and mid-brain were significantly raised at the higher dose of styrene. Therefore, elevated serotonin levels in these brain regions may account for styrene-induced learning.

Gassings due to methylene chloride, xylene, toluene, and styrene reported to Her Majesty's Factory Inspectorate 1961-80.

For the period 1961-80, 118 cases of industrial gassings caused by the solvents methylene chloride, xylene, toluene, and styrene were reported to Her Majesty's Factory Inspectorate. The data have been collated and analysed according to the predetermined criteria of age, sex, mode and circumstances of use, clinical effect, and outcome. The means of collection of the data and their objectivity is discussed. The study shows the narcotic effect of these solvents and underlines the dangers of their use in confined spaces. Symptoms were most commonly attributable to the nervous and respiratory systems. The problem of addiction and the vulnerability of the younger worker is also discussed.

Congenital malformations, mortality and styrene exposure.

The prevalence of congenital malformations among children born to styrene-exposed male and female workers, as well as the mortality of the exposed workers, was studied. A cohort of 2,209 workers (1,698 men, 511 women) was selected from the personnel files of 160 workplaces using styrene in the manufacture of reinforced plastic products. The earliest exposure histories began in 1960, but the majority of workers had been exposed after 1967. The data on children born to the exposed workers were linked with those of the Register of Congenital Malformations. The number of malformations of children born to the workers was, both before and during the styrene exposure, below the expected values. In the cohort there were 37 observed deaths (expected 74.0), six of which were due to cancer (expected 13.0). The cancer sites were the stomach (2 cases), bronchus (1), breast (1), ovary (1), and kidney (1 case). There were no cases of lymphatic or haematopoietic cancer. Most of the cancers appeared after short exposure times and soon after the commencement of exposure.