(2002). A COMPREHENSIVE EVALUATION OF THE POTENTIAL HEALTH RISKS ASSOCIATED WITH OCCUPATIONAL AND ENVIRONMENTAL EXPOSURE TO STYRENE. Journal of Toxicology and Environmental Health, Part B: Vol. 5, No. 1-2, pp. 1-263.

A comprehensive evaluation of the potential health risks associated with occupational and environmental exposure to styrene.

Chromosome aberration frequencies in 61 employees potentially exposed to ethylene oxide (ETO) were compared with those in unexposed control groups. We studied 3 worksites with differing historical ambient levels of ETO. Within worksites, groups were classified as high potential exposed, low potential exposed, or controls. Further control groups including an off-site community control group were added to give a total of 304 control individuals. Blood samples were drawn several times over a 24-month period. Aberrations were analyzed in 100 cells per sample after culture for 48–51 h. Worksites I, II and III respectively represented increasing levels of potential ETO exposure. At worksites I and II, no consistent differences in aberration frequencies were found among groups. At worksite III aberration frequencies in potentially exposed individuals were significantly increased compared with controls. The frequencies of cells with aberrations were 5.6% for the 2 individuals in the high potential exposure category and 2.6% for 23 persons in the low potential exposure group. The overall frequency of cells with aberrations in the matched control individuals was 1.4%. In the total control group of 304 individuals we found significant increases in aberrations associated with smoking and with increasing age. We have also reported previously an association between sister-chromatid exchange (SCE) frequency and ETO exposure (Stolley et al., 1984). When aberration frequencies were compared with levels of SCEs there was only a weak overall association. The correlation was found in potentially exposed but not in control groups, and for any individual, one observation could not be used to predict the other.

Chromosome aberrations in individuals occupationally exposed to ethylene oxide, and in a large control population☆

The genetic toxicology of styrene and styrene oxide.

Samples of blood were collected from a group of plant workers engaged in the manufacture of ethylene oxide (EO) for periods of up to 14 years and also from a group of control personnel matched by age and smoking habits. Peripheral blood lymphocytes were cultured for cytogenetic analysis. Selected immune and haematological parameters were also investigated. The results of these studies showed no statistically significant difference between the group of plant workers and the control group in respect of any of the biological parameters investigated in this study. Nevertheless, duration of employment in EO manufacturing was positively correlated (p less than 0.05) with the frequency of chromosome breaks and with the percentage of neutrophils in a differential white blood cell count and negatively correlated (p less than 0.05) with the percentage of lymphocytes. As the values of these parameters remained within the normal limits of control populations, the correlations were considered to have no significance for health. Atmospheric concentrations of EO were determined using personnel air samplers and were generally below the detection limit (less than 0.05 ppm) during stable plant operations, although transient concentrations of up to 8 ppm were occasionally recorded. The amount of alkylation (2-hydroxyethyl groups) of the Nt atom of histidinyl residues in haemoglobin was also measured in an attempt to gauge recent individual exposures to EO. Variable but, in most instances, readily measurable amounts of Nt-(2'-hydroxyethyl)-L-histidine (Nt represents the N3 atom of histidine) were found in the haemoglobin of plant workers and in the control group who had not knowingly been exposed to an exogenous source of EO. There was no statistically significant difference between the results obtained in the control group and in the group of plant workers.

https://oem.bmj.com/content/oemed/42/1/19.full.pdf

Cytogenetic, immunological, and haematological effects in workers in an ethylene oxide manufacturing plant

DISCLAIMER The use of company or product name(s) is for identification only and does not imply endorsement by the Agency for Toxic Substances and Disease Registry. A Toxicological Profile for Styrene, Draft for Public Comment was released in October 2007. This edition supersedes any previously released draft or final profile. Toxicological profiles are revised and republished as necessary. For information regarding the update status of previously released profiles, contact ATSDR at: FOREWORD This toxicological profile is prepared in accordance with guidelines* developed by the Agency for Toxic Substances and Disease Registry (ATSDR) and the Environmental Protection Agency (EPA). The original guidelines were published in the Federal Register on April 17, 1987. Each profile will be revised and republished as necessary. The ATSDR toxicological profile succinctly characterizes the toxicologic and adverse health effects infonnation for these toxic substances described therein. Each peer-reviewed profile identifies and reviews the key literature that describes a substance's toxicologic properties. Other pertinent literature is also presented, but is described in less detail than the key studies. The profile is not intended to be an exhaustive document; however, more comprehensive sources of specialty information are referenced. The focus of the profiles is on health and toxicologic infonnation; therefore, each toxicological profile begins with a public health statement that describes, in nontechnical language, a substance's relevant toxicological properties. Following the public health statement is infonnation concerning levels of significant human exposure and, where known, significant health effects. The adequacy of infonnation to detennine a substance's health effects is described in a health effects summary. Data needs that are of significance to protection of public health are identified by ATSDR. Each profile includes the following: (A) The examination, summary, and interpretation of available toxicologic infonnation and epidemiologic evaluations on a toxic substance to ascertain the levels of significant human exposure for the substance and the associated acute, subacute, and chronic health effects; (B) A determination of whether adequate infonnation on the health effects of each substance is available or in the process of development to detennine levels of exposure that present a significant risk to human health of acute, subacute, and chronic health effects; and (C) Where appropriate, identification of toxicologic testing needed to identifY the types or levels of exposure that may present significant risk of adverse health effects in humans. The principal audiences for the toxicological profiles are health professionals at the Federal, State, and local levels; …

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Toxicological profile for styrene

Employees of plants where alkylene oxide is manufactured or processed were subjected to mutagenicity studies carried out on lymphocyte cultures in accordance with the methods of Moorhead at al, de Jong and Anders. The employees were divided into four groups, according to their periods of exposure: (1) Long-term exposure for more than 20 years; (2) exposure for less than 20 years; (3) long-term exposure and accident (ethylene oxide inhalation or skin contact); and (4) accident, i.e., brief high exposure to ethylene oxide. Measurement of the concentrations in various sections of the plant yielded values of up to 3 ppm under conditions of normal operation. However, this figure rose briefly to 1900 ppm under plant breakdown hat workers were subjected to higher exposure in the past. One hundred metaphases per person were analyzed for chromosome aberrations. The results are given in Tables 1 through 4. A significant increase in the aberration rate was found only in employees in Group 1. This was confirmed by a control examination carried out one year later. The employees of groups 2, 3 and 4 displayed no significant increases. However, in evaluating these findings, it should be noted that the employees had been in contact with a wide range of substances and products in the course of their occupation, which means that the increased aberrations rate found cannot be attributed unequivocally to exposure to a particular substance.

Mutagenicity study of workers exposed to alkylene oxides (ethylene oxide/propylene oxide) and derivatives.

Cytogenetic evaluation of 24 employees exposed to an average styrene concentration rate of 6.0 ppm in the laboratory, and to 58.1 ppm in the polyester processing pilot plant, has revealed no statistically significant increase in chromosome aberration rates as compared to a matched control group.

H. Schwegler

Papers

Mutagenicity study of workers exposed to alkylene oxides (ethylene oxide/propylene oxide) and derivatives.

Chromosome investigations in lymphocytes of workers employed in areas in which styrene-containing unsaturated polyester resins are manufactured.