As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THE CREW RETURNED THE AIRCRAFT TO THE GATE DUE TO STRONG SULFUR TYPE SMELL AFTER SECOND ENGINE START. AFTER ENGINE SHUTDOWN, SMELL REMAINED AND ACTUALLY GOT STRONGER. CREW REPORTED ODOR OCCURRED AFTER DE-ICING PROCEDURE. FOLLOWED ODI PREVENTION FOR ATA2172. REPLACED COALESCER BAGS AND COMPLETED A DUCT BURNOUT. SYSTEM OPERATIONALLY CHECKS NORMAL AND THE AIRCRAFT RETURNED TO SERVICE.