As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLIGHT 5886 DURING CLIMBOUT OF BWI CREW NOTED EVIDENCE OF SMOKE IN THE COCKPIT, CREW DECLARED AN EMERGENCY AND RETURNED TO THE FIELD, LANDING WITHOUT INCIDENT. PERFORMED ENGINE RUNS, DISCREPANCY COULD NOT BE DUPLICATED. AIRCRAFT HAD BEEN DE-ICED PRIOR TO DEPARTING BWI, SUSPECT DE-ICING FLUID ENTERED APU INLET CAUSING CONTAMINATION OF AIR DISTRIBUTION SYSTEM.