Negative Exposure Assessment

A "negative initial exposure assessment" is a demonstration by the employer that employee exposure during an operation is expected to be consistently below the permissible exposure limits (PELs).

The determination of a "negative exposure assessment" is job-specific. It can apply only to jobs performed by trained employees. An employer may demonstrate that exposure will be below the PELs by data conforming to the following criteria:

1. Objective data - demonstrating that the product or material containing asbestos minerals, or the activity involving such product or material, cannot release airborne fibers in concentrations in excess of the permissible exposure limits (Time Weighted Average or Excursion Limit) under those work conditions having the greatest potential for releasing asbestos (the worst case), or
2. 2) Prior exposure monitoring results - for both permissible exposure limits (PELs); within the previous 12 months; using the sampling and analytical methods of the asbestos standard in effect; work operations closely resemble current or projected operations in terms of processes, types of material, control methods, work practices, environmental conditions, and employee training; results indicate that employee exposures will not exceed PELs, or
3. 3) Results of initial exposure monitoring of the current job - cover operations that are most likely during the performance of the entire asbestos job to result in exposures over the PELs.

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