Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural MEL / CDL; Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor
General Flight Cancelled / Delayed; General Maintenance Action
Aircraft
After boarding was completed and main cabin door shut. Flight Crew started both engines for turn out and Flight Attendant notified cabin secure but aircraft seemed hazy and had an odor. Shut down engines and had Operations come back with stairs and opened main cabin door. Called Dispatch and talked to Maintenance while deplaned the passengers. Pack 2 on with Pack 1 off produced smoke/haze. Flight Crew detected with maintenance on the phone. Pack 2 started to make an unusual noise just prior to engine start but no other indication was noticed. Talking through with Maintenance we discussed the cause was pack 2. Deplaned. MEL'd pack. Reloaded passengers and went to ZZZ1 as normal but delayed.
EMB-145LR Captain reported a fumes event prior to pushback.