Occupational exposure to chemical agents in the paper industry.

As part of an International Agency for Research on Cancer (IARC) international epidemiological study of workers in the pulp and paper industry, previously unpublished exposure measurements were assembled in a database. This article summarizes the results of 3,873 measurements carried out in the production departments of paper and paperboard mills and recycling plants in 12 countries. In the paper and paperboard mills, most of the agents were measured in the pulping and refining departments and in on-machine coating and winding of paper/paperboard. Exposures to asbestos, carbon monoxide, formaldehyde, fungal spores, bacteria, nitrogen dioxide, minerals dusts, paper dust, sulphuric acid and different solvents sometimes exceeded exposure limit values. In the re-pulping and de-inking departments of recycling plants high exposures to formaldehyde, fungal spores, bacteria and paper dust were observed. High exposures to asbestos, bioaerosols, carbon monoxide and paper dust were found in many departments; ammonia, formaldehyde, mineral and paper dust and solvents were found in coating machines; and diphenyl and polychlorobiphenyls (PCBs) were found in some special circumstances. Measurements in the newsprint and uncoated paper machine departments revealed only a few elevated exposures. In nearly all departments, measurements of epichlorohydrin, PCBs, sulphur dioxide, hydrogen sulphide and mercaptans tended to be low, often even below their detection limits. In spite of some uncertainties in the measurement data, the study provides new insights into the level and variation of occupational exposures of production workers in the paper and paperboard industry.

Distribution and skewness of occupational exposure sets of measurements in the Norwegian industry.

Aggregated occupational sets of exposure measurements from the Norwegian industry registered in the exposure database EXPO at The National Institute of Occupational Health, Oslo were examined with respect to distributions and skewness. Data for lead in blood show a truncated almost normal distribution because of regulations for workers with high lead in blood concentrations. The styrene, dichloromethane and acetone measurements show quasi log-normal distributions possibly because of over-representation of worst-case measurements. The other personal and stationary measurements are relatively good fitted to a log-normal model. The stationary measurements indicate generally lower mean levels than the corresponding personal measurements. The statistical parameter skewness is valuable in connection with an exposure database as a distribution test for raw data and log-transformed data.

Occupational exposure to styrene in Norway, 1972-1996.

Occupational exposure to styrene has been of special concern in Norway since the beginning of the 1970s, especially the exposure in the reinforced plastic industry. Campaigns have been carried out by the Norwegian Directorate of Labour Inspection and various measures have been set forth to reduce the workers' exposure to styrene. Alongside the campaigns, extensive monitoring programs were carried out. The measurement results are compiled in the database EXPO at the National Institute of Occupational Health (Norway). This article presents a statistical analysis of the measurement data to assess the occupational exposure to styrene in Norway since the 1970s. Results from 7,011 measurements carried out in 234 enterprises covering the period 1972-1996 are included in the database. The analyses show occupational exposure to styrene of 33.0 ppm (median) (mean: 49.4 ppm) for this period. The analyses show a decrease from a median of 62 ppm in the 1970s to 7.1 ppm in the 1990s. The analyses do not disclose any crucial impact from any single preventive measure implemented by the authorities to reduce exposure level. The reduction in the level is probably due to a contribution from different measures. The decline in the styrene exposure coincides with a similar reduction in other countries, and it may be that international concern and technical improvements in the manufacturing process have been an important factor in the exposure level reduction in the Norwegian plastic reinforced industry as well.

Occupational exposure to chemical and biological agents in the nonproduction departments of pulp, paper, and paper product mills: an international study.

As part of an international epidemiological study of workers in the pulp and paper industry, previously unpublished exposure measurements were assembled in a database. This article describes 7293 measurements in nonproduction departments from 147 mills in 11 countries. The greatest variety of agents was measured in the maintenance, construction, and cleaning department, where high exposures to asbestos, chromium [VI] compounds, copper, mercury in urine, nitrogen dioxide, ozone, styrene, sulfur dioxide, trichloroethylene, and welding fumes were observed. Measurements in the storage, yard, loading, and shipping department indicated high exposures to asbestos, carbon monoxide, fungal spores, nitrogen oxides, sulfur dioxide, and total dust. The steam and power generation department had high exposures to methyl mercaptan, silica, and total dust. Measurements in process and effluent water treatment, laboratory and research, engineering, and office, administration, and cafeteria areas had few elevated exposures. Throughout the nonproduction departments, measurements of pulp-production chemicals such as chlorine and sulfur compounds tended to be low, with many below detection limits. There were some problems with the available data; in particular, detection limits were often not specified, and the data tended to be clustered in such a way that sources of exposure variability could not be distinguished. Despite these problems, the data provide new insight into the exposures of nonproduction pulp and paper industry personnel.

In vitro screening for metabolic interactions among frequently occurring binary mixtures of volatile organic chemicals in Norwegian occupational atmosphere.

Surveys of Norwegian industrial occupational atmosphere between 1983 to 1996, have identified the 12 most frequent occurring binary combinations of volatile organic chemicals. These combinations were tested in vitro for mutual inhibition or enhancement of metabolism by the head space vial equilibration technique with liver S9 obtained from in vivo untreated or pretreated (with the binary mixture) rats. The in vitro system responded to in vivo pretreatment by increasing the metabolic rate of several potentially toxic organic chemicals such as toluene, xylene, styrene, and dichloromethane. In untreated liver S9, the metabolism of several of the tested binary pairs was inhibited when coexposed in vitro to their most prevalent follower as shown for instance for ethanol (with ethyl acetate), dichloromethane (with styrene) and mutually between toluene and xylene. This inhibitory effect disappeared, however, for several of the solvents when combined with the in vivo induced liver S9, a situation which may be the most relevant for occupational exposure. It is concluded that several metabolic interactions occur between low-molecular weight volatile chemicals found in occupational air. These are both inductive and inhibitory in nature and a further mechanistic evaluation including a higher number of differentiated dosage levels, must be performed before a possible health hazard can be confirmed or rejected for the investigated combinations.

Trends in mesothelioma incidence in Norway 1960-1988.

The age and sex related trends in incidence of malignant mesothelioma and trends in notification of mesothelioma to the Labour Inspection between 1960-88 are investigated. For men, the age-adjusted incidence rate increased from 0.4 per 100,000 in the period 1960-69 to 1.4 per 100,000 in the period 1980-88. The number of mesotheliomas notified to the Labour Inspection increased from only 4 in the period 1960-69 to 165 in the period 1980-88. The incidence rate among women was unchanged, about 0.1 per 100,000.