What was found
L-R BI AIR FAIL, AT FL190 L-R BLEED AIR CAS ANNUNCIATION ILLUMINATED, PULLED OUT PILOT CHECKLIST AND FOLLOWED THE PROCEDURE. CABIN CLIMBED TO 10,500FEET ON THE DESCENT TO 9000FT WHERE CABIN WAS TOTALLY UNPRESSURIZED. LANDED AT NEAREST SUITABLE AIRPORT. EMERGENCY DECLARED. TROUBLESHOOT LEFT AND RIGHT "BLEED AIR FAIL" PER B300 KA FUSION MM 26-11-10, 21-10-00. PERFORMED ENGINE RUN OPS CHECK PRESSURIZATION SYSTEM. NO DISCREPANCY NOTED. OPS CHECK DEICE SYSTEM TO ISOLATED PNEUMATIC SYSTEM PRESSURE DROP, AND NO DICREPANCY. DOWNLOADED OMS ALL REPORT AND SUBMITTED TO FSR FOR REVIEW AND NO-FAULT HISTORY. NO FURTHER ACTION TAKEN AT THIS TIME.