A320
Flight Crew Air Transport Pilot (ATP)
Aircraft Equipment Problem Less Severe; Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor; Flight Deck / Cabin / Aircraft Event Illness / Injury
Air Traffic Control Provided Assistance; Flight Crew Returned To Gate; General Flight Cancelled / Delayed; General Physical Injury / Incapacitation
Aircraft
We started both engines after push back. After second engine start we were cleared to taxi. Approximately 2-3 minutes into our taxi; the number 2 and 3 FAs called the flight deck to tell us there was a strong odor of 'gas'. They said it seemed to be dissipating however one of the FAs felt dizzy and was getting a headache. We requested to pull over and evaluate the situation. I spoke to the FAs again and I asked them if it had gotten better and they said yes; but that they said one of them still felt dizzy. I spoke with the [Chief Pilot] and discussed my concerns continuing the flight with an FA that is complaining of a headache and being dizzy coupled with 1/8 mile visibility and a takeoff alternate. He asked if I would call the FA back and confirm he was no 'fit for duty'; which I did. The FA confirmed he was not fit so we returned to the gate; deplaned; and FA 2 and 3 were taken to the hospital for evaluation.
A320 Captain reported a ground gate return due to Flight Attendant notification of physiological issues experienced from cabin fumes. Two flight attendants were replaced and treated at local hospital.