As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SEA-BOTH FLIGHT ATTENDANTS REPORT HAZE AND SMELL IN CABIN AND BURNING EYES. APU ON CABIN DUCT AND FC DUCT TEMPERATURES BELOW 30 DEGREES. GROUND RAN APU FOR SEVERAL HOURS. CYCLED BLEED AIR UP AND DOWN SEVERAL TIMES. NO HAZE OR SMELL DETECTED. NO OTHER FAULTS NOTED. NO PARTS REPLACED. AIRCRAFT RETURNED TO SERVICE.