As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLIGHT 5018 - EN ROUTE CVG-PIT IMMEDIATELY AFTER TAKE-OFF NOTICED SMOKE IN THE COCKPIT, CREW DECLARED AN EMERGENCY AND RETURNED TO CVG. FLIGHT LANDED WITHOUT INCIDENT. DISCOVERED CAUSE OF SMOKE TO BE GLYCOL EMANATING FROM APU BLEED AIR. REPLACED THE COALESCER SOCK.