This testimony includes considerations which may be relevant to the Environmental Protection Agency Guideline for exposure related measurements. The proposed guidelines emphasize the importance of developing well designed studies to assess current exposures so that a prospective assessment of future exposure and risk can be estimated. The comprehensiveness of an assessment depends on the availability and quality of past workplace and work practice data. Two of the more important disciplines, industrial hygienist and epidemiologist, would be essential in a multidisciplinary approach to exposure assessment. The testimony also considers direct measurement of exposure, developing a sampling strategy, sampling location and frequency, sampling duration, reporting data near the detection limit, the relevance of measurement data for the intended exposure assessment, measurements and modeling, and the role of limit of detection values in measurements used to estimate exposure.