Job Exposure Matrix based on NIOSH study

The job-exposure matrix developed for this study on asbestos exposure was based on that used in the earlier NIOSH study, with some important exceptions.

In the earlier study, workers with "common laborer" job assignments and some workers with unknown job assignments were assigned the relatively low exposure estimated for the mill yard.

In the current analysis, these workers were assigned the average estimated exposure intensity for all unskilled jobs during the relevant calendar time period. This resulted in higher estimates of cumulative exposure, with likely attenuation of the effect estimators.