Abstract
The decision scheme used in the NIOSH Occupational Exposure Sampling Strategy and in several OSHA health standards is examined to determine how average exposure level and exposure variability affect the decisions produced. As exposure variability increases, the NIOSH decision scheme tends to indicate incorrectly that monitoring may be terminated for high exposure risk environments for which monitoring should definitely be continued or even increased. A simple modification to the NIOSH scheme reduces this trend but does not eliminate it. An alternative decision scheme based on one-sided tolerance limits eliminates defects found in the NIOSH schemes including the trend toward inappropriate termination of monitoring.