SMOKE IN THE COCKPIT DURING INITIAL TAXI.

Narrative

FO IOE; HIS SECOND LEG. PUSHED OFF GATE X MSP. STARTED BOTH ENGS. ANTI ICE ON; BEGAN TAXI. AS WE TURNED 90 DEGS FROM THE GATE; I NOTICED AN ELECTRICAL SMELL. IT BECAME STRONGER AS I LOOKED X COCKPIT TO THE FO TO REALIZE THAT WE HAD A HAZY WHITE SMOKE BEGINNING TO FILL THE COCKPIT. I TOLD THE FO TO TELL GND CTL WE WERE RETURNING IMMEDIATELY TO GATE. I STARTED A HARD L TURN; TOLD THE FO TO CALL MSP OPS AND INFORMS WE WERE COMING BACK TO GATE IMMEDIATELY -- SOME 30 YARDS AHEAD. AS WE TURNED ONTO THE LEAD-IN LINE; I SHUT DOWN #2 ENG; MADE A PA TO THE FLT ATTENDANT TO REMAIN SEATED AND FOR THE PAX TO STAY SEATED FOR FURTHER INSTRUCTIONS. THE GND PERSONNEL WERE RUNNING OUT TO PARK US WITH AN AGENT COMING DOWN THE JETBRIDGE. WE ACCOMPLISHED A NORMAL ENG SHUTDOWN. THE ACFT HAD A SERIES OF WRITE-UPS FOR APU WITH LOW PRESSURE. IT WAS EVIDENT TO ME THAT THIS SMOKE WAS LIKELY TO BE COMING FROM THE #1 PACK. MAINT CONFIRMED THIS IN THEIR TROUBLESHOOTING. PLACARDED #1 PACK AND CONTINUED MSP PERSONNEL WERE SUPERB IN THEIR RESPONSE (LESS THAN 30 SECONDS FROM OUR CALL TO GET A FULL COMPLEMENT OF GND CREWS) AND SUBSEQUENT HANDLING OF THE SIT. SMELL ALSO OCCURRED AFT OF WINDOW EXITS.