As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) PILOT REPORTED ON LONG TAXI, THAT THE PASSENGER COMPLAINED OF MIST/SMOKE IN THE CABIN. CREW ALSO REPORTED THAT THEY LOST ALL QUANTITY NR 1 UTILITY HYDRAULIC SYSTEM. AIRCRAFT RETURNED TO GATE, FLIGHT ATTENDANTS PASSED AROUND PORTABLE OXYGEN BOTTLES DUE TO CHOKING AROMA. PASSENGER DEPLANED ASAP. NR 1 UTILITY SWITCH LOOSE IN ITS MANIFOLD AND NOT LOCK WIRED. SWITCH REPLACED.