To identify critical weeks of anomalous condemns, a modification of the 'C3' version of the Early Aberration Reporting System was applied to the STB condemn series (2) . In addition to examining alerts by basin, the alerting algorithm was applied to individual plant data. Data processing was performed using SAS version 9.1 and an Excel-based 'Alerting Algorithms Tool' developed and published by Dr. Howard Burkom (3) .