Physiological - Other
Flight Deck / Cabin / Aircraft Event Illness / Injury; Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor
General Maintenance Action; General Flight Cancelled / Delayed; General Work Refused
Aircraft
We initially had to return to the gate before takeoff because there was a computer reset mechanical. Upon returning to the gate; while waiting for mechanics to fix the issue; a passenger told me; Flight Attendant B; that she had a headache and was feeling lightheaded and a few passengers were feeling the same way around her (Row 16). I went to Row 16 to ask people how they were feeling and to see if I smelled anything unusual. A few passengers nearby claimed to feel lightheaded and one said that he had a headache but did not know why. One of the passengers said that she felt like that because of the air vent; claimed she could smell the exhaust and fumes through the air vent. I could not smell anything and Flight Attendant C and D could not smell anything either when they walked by. I told the Captain about it and he went into the cabin to see if he could smell anything and he said he could not. After the computer reset mechanical issue was fixed; we closed the main cabin door.Then; we got the release to push back again. Then the D Flight Attendant called the front to report the strong fume odor in the aft of the cabin. The A asked the C Flight Attendant and the B Flight Attendant if we could walk through the cabin to verify the smell and as we approached Row 17 we noticed the burning acrid smell; metallic like dirty socks. The further back that we approached the stronger the smell was. The smell in the aft galley was intolerable and the D flight Attendant started vomiting. Flight Attendant C and myself started to feel nauseous; lightheaded; dizzy; itchy throat and eyes.The C Flight Attendant called the Captain and informed the issue and we headed back to the gate. When the C Flight Attendant went back to take his position to disarm doors; the same smell in the front galley was strong too. Passengers in the front of the aircraft started to complain about it and passenger seated in 1 C started to feel very nauseous but she declined medical attention. Main cabin door was opened and we deplaned passengers EMT's were waiting in the gate for any passengers that needed help. We were checked out by EMT's and transported to the hospital for a further check out.
A320 Flight Attendant crew reported being notified by passengers of 'burning acrid dirty socks' odor during ground delay. Fumes gradually intensified resulting in health issues among cabin crew and passengers.