As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING TAXI, SMOKE RAPIDLY FILLED THE COCKPIT AND THE CABIN. EMERGENCY SHUTDOWN OF ALL SYSTEMS WAS PERFORMED, GROUND EMERGENCY DECLARED AND AIRCRAFT EVACUATED. IT WAS FOUND DUE TO FAILURE IN THE APU, OIL ENTERED THE BLEED AIR DUCT WHICH CAUSED THE SMOKE. SYSTEM IS IN TROUBLESHOOTING/TEARDOWN PROCESS.