As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
IAH - FLIGHT 3454, THE CREW REPORTED SMOKE IN THE CABIN SHORTLY AFTER DEPARTURE. THE AIRCRAFT RETURNED TO IAH WHERE IT LANDED WITHOUT INCIDENT. MAINTENANCE RESECURED A LOOSE HOSE ON THE LEFT HAND AIR CYCLE MACHINE, AND THE AIRCRAFT WAS APPROVED FOR RETURN TO SERVICE.