As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
TEN MINUTES BEFORE PUSHBACK CABIN FILLED WITH SMOKE. RAN QRH PROCEDURES. DEPLANED PASSENGERS THROUGH 1L DOOR. APU AUTO SHUTDOWN. UPON INVESTIGATION, FOUND DRAIN CHIP DETECTOR FULL OF METAL PARTICLES AND APU AIR PLENUM CRACKED. PERFORMED REMOVAL OF OIL CONTAMINATION FROM AIR CONDITIONING AND PNEUMATIC SYSTEMS. SMOKE REMOVED AND ODOR CLEARED. APU DEFERRAL ON LP 6094484.