DEVELOPMENT OF A JOB EXPOSURE MATRIX IN T HE FRENCH HARD METAL-INDUSTRY

A job exposure matrix (JEM) was developed by a committee of experts us ing the DELPHI method, in the French hard metal industry, in order to assess occupational exposures to cobalt along with tungsten carbide re sulting from the industrial process. This JEM is part of a nested case -control study, carried out within the historical cohort of workers ev er employed in these factories, aimed at assessing lung cancer risk. T he committee included 8 experts hygienists, chemical engineers, occupa tional physicians and epidemiologists. The JEM was developed in four s tages : (i) visit of factories, (ii) definition of lines (job-periods) and columns (exposures) of the JEM, (iii) definition of coding proced ures, (iv) coding the cells of the JEM. This last stage used a method derived from the DELPHI method. Throughout the study period 1945-1994, 320 job-periods and 21 agents were defined. A quantitative assignment (level 0 to level 9) along with a frequency code (1 to 3) was attempt ed for 4 agents, whereas only a qualitative assignment (non exposed/ex posed, i.e. 0/1) was done for the other agents. An additional probabil ity code (1 to 3) was assigned to all agents. This procedure led to 46 columns and 14,720 cells in the JEM. When applying the DELPHI method, the consensus of the committee was obtained for 85 % of all cells aft er the first individual assignment of experts, 88 % after the second i ndividual assignment and 100 % after the third assignment by the exper ts all together. In order to validate the JEM, these expert assignment s will be brought together with the results of exposure measurements t hat were performed in some workplaces of these factories. The JEM will also be linked with the data base of the case-control study for the e xposure assessment of cases and controls.