As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON CLIMB-OUT, RECEIVED SMOKE TOILET MESSAGE WITH SMOKE IN CABIN. QRH FOLLOWED WITH RETURN TO DEPARTURE AIRPORT WITH UNEVENTFUL LANDING. MX PERFORMED ENGINE RUNS AND CONFIRMED SMOKE, FOUND TO BE RESIDUAL DEICE FLUID IN PACKS, HIGH POWER RUNS PERFORMED AND SMOKE DISAPPEARED. (K)