Numerous protective covers, used in conjunction with an electrical appliance, failed during assembly with the mating components. The failures were traced to a particular production lot of the covers and occurred during insertion of the screws into the corresponding bosses. The parts had been injection molded from an ABS resin to which regrind was routinely added. Inspection of both the failed covers and retained parts, which exhibited normal behavior during assembly, included visual inspection, micro-FTIR in the ATR mode, and analysis using DSC. The FTIR results indicated the presence of contaminant material exclusively within the ABS resin used to...