B767-300 and 300 ER
Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument
Distraction; Situational Awareness
Aircraft Equipment Problem Less Severe; Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor
General Maintenance Action
Aircraft
During push back; we received a Main Cargo Fire warning. There was no smell in the cockpit. We thought maybe it was a false alarm due to the fact we had just been de-iced. We had maintenance pull us back into the gate. As we were being pulled back in; the warning would momentarily discontinue but would then come back on. Maintenance came on board to investigate and noticed a low lying odorless fog throughout the main cargo deck.CFR (Crash Fire Rescue) was called to investigate. Cans were moved to identify source.Prior to push back; we were de-iced and waited a least one minute before the packs were turned on. Upon leaving for the hotel I was told that maybe de-ice fluid entered somewhere it shouldn't have.Cause - I still don't know; but speculation was de-ice fluid entered somewhere it shouldn't have.
Captain reported a fumes event during pushback resulting in the aircraft being pulled back to the gate for Maintenance investigation.