As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON CLIMB-OUT ABOUT 4,000 FEET, BOTH SMOKE ALARMS IN REAR OF A/C SOUNDED AND THERE WAS A LIGHT MIST/SMOKE VISIBLE IN THE A/C. THE SMOKE ALARMS COULD NOT BE SILENCED BY FANNING TO VENTILATE BOTH HPS BLEEDS ON A/C. PACKS TURNED OFF. NO HELP. CORRECTIVE ACTION FOUND APU LEAKING OIL IN EXHAUST AND BACK INTO A/C SYSTEM. REPLACED OIL SEAL AND BURNED OUT DUCT. OPS CHECK OK.