Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine; Flight Crew Instrument
Situational Awareness
Flight Deck / Cabin / Aircraft Event Illness / Injury; Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor
General Flight Cancelled / Delayed; General Maintenance Action
Aircraft
Prior to engine start during push back; the flight attendants called and reported a 'chemical smell or dirty sock smell.' We elected to terminate the push back and were pulled back into the gate. We turned off the packs and the APU bleed air. We deplaned the passengers and crew and accomplished the QRH for smoke odor/fumes. While exiting one passenger began having symptoms of nausea and vomited. We called Paramedics. After deplaning 2 FAs began having headaches and paramedics treated them in the terminal. No one was transported to the hospital.
Captain reported Flight Attendant notification of 'chemical or dirty socks' smell during pushback for departure. Crew returned to gate for Maintenance. Deplaned with a passenger and two flight attendants experiencing health issues.