title: Determinants of exposure to dust and dust constituents in the Norwegian silicon carbide industry.
abstract: BACKGROUND
  The aim of this study was to identify important determinants of dust exposure in the Norwegian silicon carbide (SiC) industry and to suggest possible control measures.
  
  
  METHODS
  Exposure to total dust, respirable dust, quartz, cristobalite, SiC, and fiber was assessed in three Norwegian SiC plants together with information on potential determinants of exposure. Mixed-effect models were constructed with natural log-transformed exposure as the dependent variable.
  
  
  RESULTS
  The exposure assessment resulted in about 700 measurements of each of the sampled agents. Geometric mean (GM) exposure for total dust, respirable dust, fibers, and SiC for all workers was 1.6mg m(-3) [geometric standard deviation (GSD) = 3.2], 0.30mg m(-3) (GSD = 2.5), 0.033 fibers cm(-3) (GSD = 5.2), and 0.069mg m(-3) (GSD = 3.1), respectively. Due to a large portion of quartz and cristobalite measurements below the limit of detection in the processing and maintenance departments (>58%), GM for all workers was not calculated. Work in the furnace department was associated with the highest exposure to fibers, quartz, and cristobalite, while work in the processing department was associated with the highest total dust, respirable dust, and SiC exposure. Job group was a strong determinant of exposure for all agents, explaining 43-82% of the between-worker variance. Determinants associated with increased exposure in the furnace department were location of the sorting area inside the furnace hall, cleaning tasks, building and filling furnaces, and manual sorting. Filling and changing pallet boxes were important tasks related to increased exposure to total dust, respirable dust, and SiC in the processing department. For maintenance workers, increased exposure to fibers was associated with maintenance work in the furnace department and increased exposure to SiC was related to maintenance work in the processing department.
  
  
  CONCLUSIONS
  Job group was a strong determinant of exposure for all agents. Several tasks were associated with increased exposure, indicating possibilities for exposure control measures. Recommendations for exposure reduction based on this study are (i) to separate the sorting area from the furnace hall, (ii) minimize manual work on furnaces and in the sorting process, (iii) use remote controlled sanders/grinders with ventilated cabins, (iv) use closed systems for filling pallet boxes, and (v) improve cleaning procedures by using methods that minimize dust generation.
authors.affiliation: National Institute of Occupational Health, Oslo, Norway. solveig.foreland@stolav.no
authors.forename: Solveig
authors.initials: S
authors.lastname: Føreland
authors.forename: Berit
authors.initials: B
authors.lastname: Bakke
authors.forename: Roel
authors.initials: R
authors.lastname: Vermeulen
authors.forename: Erik
authors.initials: E
authors.lastname: Bye
authors.forename: Wijnand
authors.initials: W
authors.lastname: Eduard
mesh_terms: D000395:Air Pollutants, Occupational / Q000032:analysis*; D017554:Carbon Compounds, Inorganic / Q000009:adverse effects / Q000032:analysis*; D004391:Dust / Q000032:analysis*; D004784:Environmental Monitoring / Q000379:methods; D006801:Humans; D019570:Inhalation Exposure / Q000032:analysis / Q000706:statistics & numerical data; D009664:Norway / Q000453:epidemiology; D016273:Occupational Exposure / Q000032:analysis / Q000706:statistics & numerical data; D016272:Occupational Health / Q000592:standards; D009790:Occupations / Q000145:classification*; D011791:Quartz / Q000009:adverse effects / Q000032:analysis; D017655:Silicon Compounds / Q000009:adverse effects / Q000032:analysis*; D012822:Silicon Dioxide / Q000009:adverse effects / Q000032:analysis
chemical_list: D000395:Air Pollutants, Occupational; D017554:Carbon Compounds, Inorganic; D004391:Dust; D017655:Silicon Compounds; D011791:Quartz; D012822:Silicon Dioxide; C022088:silicon carbide