Comparison of self-assessment and expert assessment of occupational exposure to chemicals.

OBJECTIVES: Occupational assessments of chemical exposure are often inadequate because of difficulties in obtaining sufficient numbers of measurements by trained professionals (experts). The objective of this study was to determine whether workers can provide unbiased data via self-assessments of exposure facilitated by the use of simple passive monitors for personal sampling. METHODS: Untrained workers obtained personal measurements of their exposures to gaseous contaminants (terpenes in sawmills and styrene in reinforced plastics factories) with passive monitors and written instructions. To study the validity of the self-assessments, an occupational hygienist performed exposure measurements on the same occupational groups after the workers had obtained two or more measurements independently. The potential bias of the self-assessments was evaluated by comparing the self-assessments with the expert assessments in mixed-effects statistical models. RESULTS: A total of 153 terpene (97 self and 56 expert) and 216 styrene (159 self and 57 expert) measurements were obtained from four sawmills and six reinforced plastics factories, respectively. No significant differences in the geometric mean exposures were observed between the self-assessments and the expert assessments in 3 of 4 sawmills and 5 of 6 reinforced plastics factories (P > 0.10). The potential bias of the self-assessments of exposure ranged from less than 0.1% to 102% and was less than 17% in 9 of the 10 groups investigated. CONCLUSIONS: The results indicate that untrained, unsupervised workers are able to collect consistently unbiased exposure data by employing currently available passive monitors.

Self-assessment of exposure--a pilot study of assessment of exposure to benzene in tank truck drivers.

Occupational hygienists or safety engineers perform exposure assessments, mostly with very little participation by the workers. The objective of our study is to involve the workers themselves in the assessment and measurement procedure, the self-assessment method (SAE). A pilot study has been carried out involving tank truck drivers at a company transporting gasoline. The drivers were supposed to decide themselves when, and how often, they wanted to measure benzene exposure by using diffusive samplers that were then sent by mail for analysis. After every measurement they received their own results in a personal document for interpretation. The company management also received a document, which summarized all the drivers' measurements. Expert measurements, with the same type of sampler, were also accomplished to evaluate the self-assessments. The geometric mean and the 95 percent confidence intervals of the measurements made by the drivers (29 measurements) was 0.17 (0.11-0.26), and by an occupational hygienist (8 measurements) 0.12 mg/m3 (0.04-0.37). The results show that the drivers technically can perform SAE. Interviews with the workers and the management indicated that some kind of organizational support within the company is needed to implement the method into the regular internal control of the working environment.

Genotoxic effects in workers exposed to low levels of benzene from gasoline.

To study genotoxic effects of exposure to low levels of benzene, single-strand breaks (SSB) in DNA of leukocytes and urinary levels of the oxidative DNA adduct 8-hydroxydeoxyguanosine (8OHdG) were determined in 33 men occupationally exposed to benzene from gasoline and in 33 controls. The average exposure to benzene over a shift was determined by personal air sampling in the breathing zone. The 8-hr time-weighted average exposure to benzene was 0.13 ppm (mean value, range 0.003-0.6 ppm). Exposed workers had a significant increase of SSB (p = 0.04) over the shift compared with controls. Storage time of the samples seemed to affect the results. An analysis of samples with the same storage time showed a nonsignificant increase among the workers compared with controls. Urinary 8OHdG increased over the shift among the exposed workers but not among the controls. The highest values among the exposed workers were seen in late evening, with a slight decrease the next morning. Multiple linear analysis adjusting for smoking habits showed a significant association between the exposure level of benzene during the shift and the increase of 8OHdG in the urine over the shift among exposed workers (p = 0.02). These findings indicate a genotoxic effect in humans of benzene at relatively low exposure levels, that is, about 0.1 ppm (0.3 mg/m3).

Occurrence of self-reported asthma among Swedish bakers.

OBJECTIVE: The purpose of this study was to estimate the risk of bakers to develop asthma. METHODS: A retrospective cohort study was performed among persons trained as bakers in Swedish trade schools in 1959-1989 (N = 2923). One group of referents (I) comprised persons who followed another program in the trade schools (N = 1258), and another (II) was randomly selected from the population register (N = 1258). A questionnaire on physician-diagnosed asthma, year of onset of asthma, asthma-like symptoms, consumption of antiasthmatic drugs, change of work due to asthma, familial atopy, and work history was mailed to all the participants. The incidence rates for persons trained as bakers were estimated separately for time as a baker and time in other occupations. RESULTS: The response rate was about 75% in all three groups. There were no differences in the prevalence of asthma, asthma-like symptoms, consumption of antiasthmatic drugs, or familial atopy between the groups. Of the bakers, 2.5% had changed work due to asthma, significantly more than the referents (1.1% of reference groups I and II had changed, P < 0.05). The incidence rate for asthma among the men not working as bakers was 0.9-1.9 cases per 1000 person-years; male bakers had an incidence rate of 3.0. The relative risk for male bakers compared with all the referents was 1.8 (95% confidence interval 1.3-2.6). Women had an incidence rate of 2.3-3.0 cases per 1000 person-years, and there was no increased relative risk during work as a baker. CONCLUSIONS: Male Swedish bakers, mainly those working during the 1970s and 1980s, have an approximately doubled risk to develop asthma.

Cancer risk for European asphalt workers.

OBJECTIVES: The feasibility of a European epidemiologic study of cancer risk among asphalt workers was examined in Western Europe. The study was motivated by occupational and public health concern about possible health risk from exposure to bitumen fumes. METHODS: Information on the accessibility and quality of epidemiologic resources, retrospective worker records, mortality and cancer incidence records, and exposures was requested from research institutes and road paving and asphalt mixing companies in 15 European countries. RESULTS: Research institutes and asphalt companies in 12 countries responded. It was found that at least 44 companies in seven countries can be included in a retrospective mortality study of a minimum of 32,000 employees with 356,000 person-years (over 100 lung cancers). Coal tar will be an important confounder for these data. The power of a cohort study of workers who have never worked with tar-containing materials remains insufficient. Even in an ambispective study extending to the year 2005, the expected lung cancer deaths in a tar-free cohort would be only four. CONCLUSIONS: The results suggest that a case-referent study of lung cancer, nested in an international cohort of asphalt workers, represents the design of choice, conditionally on the possibility of assessing relevant individual life-time exposures. A cross-sectional determination of relevant biomarkers of exposure such as adducts in lymphocytes or the presence of metabolites of polycyclic aromatic compounds in urine in a group of workers exposed to bitumen fumes will provide further relevant information.

Acute nonlymphatic leukemia among deck officers on coastal tankers: a report of two cases.

Deck officers on coastal tankers may be exposed to high concentrations of cargo vapors during loading and tank-cleaning operations. Two cases of acute nonlymphatic leukemia are described. Both men had worked as chief officers on coastal tankers transporting benzene and other petroleum products.

Asbestos-associated lung effects in car mechanics.

In a study of the possible impact of asbestos exposure on car mechanics, 925 car mechanics and 109 referents (office workers in car-repair firms) were examined. They took part in a health screening in 1977-1981. The forced expiratory volumes in 1 s and the forced vital capacities of the car mechanics were close to the predicted values and did not differ from the findings of the referents. Pleural plaques were found in 41 of the mechanics but in none of the referents. Only minor changes were detected in the chest radiographs ie, 1/1 or less according to the ILO-U/C classification. It is concluded that asbestos exposure can generally cause pleural plaques in car mechanics but no substantial impairment of lung function.