Date: 201311
Local time of day: 1801-2400
Location: ZZZ.Airport, US
Flight conditions: IMC
Light: Night
Aircraft: A320
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Climb; Initial Climb
Airspace: Class B ZZZ
ATC / advisory: TRACON ZZZ
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Distraction; Physiological - Other; Time Pressure
Second reporter function: Flight Attendant (On Duty)
Anomaly: Aircraft Equipment Problem Critical; Flight Deck / Cabin / Aircraft Event Illness / Injury; Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor
Detector: Person Flight Crew; Person Flight Attendant; Person Passenger
When detected: In-flight
Result: Flight Crew Landed As Precaution; Flight Crew Returned To Departure Airport; Flight Crew Returned To Gate; General Physical Injury / Incapacitation; General Maintenance Action
Contributing factors: Aircraft; Human Factors
Primary problem: Aircraft

Narrative: Just after setting climb thrust on takeoff I noticed that the cockpit smelled like dirty socks. The First Officer confirmed the smell as well. I then transferred control of the airplane to the First Officer and contacted the flight attendants. They also confirmed the smell as well. We told them we would be retuning to departure airport and to prepare the cabin for landing. We then notified ATC that we would be returning. I contacted Maintenance and they notified Company that we would be returning. The smell started getting worse. Since we were above landing weight we completed the Overweight Landing Checklist. We landed and then returned to the gate a half hour after takeoff. All the crew was experiencing effects of chemical inhalation so we had paramedics come to the gate. Many passengers were also experiencing symptoms as well according to the flight attendants. A few of the passengers approached me and were very thankful we landed and confirmed that they were also worried about the 'smell' as it was very strong. The paramedics recommended that we (the crew) all be transported to the hospital for further treatment and observation.


Second narrative: Captain called Flight Attendant A; asked if we smelled anything; we did not. Asked Flight Attendant C to due a walk through cabin. I was C; so I did a walk through cabin. Asked B if he smelled anything; he did not. As I walking back up to my jumpseat and reached overwing; I did smell a bad snuffy odor. When I got to my jumpseat; I told Flight Attendant A I smelled the odor at overwing. She called Captain back; and apparently the odor was really bad in the flight deck; and the Captain then made an announcement; we were going to return to the gate; we were probably only 10-15 minutes out. Passengers all deplaned; [and] then all crew stayed in the jet bridge. Captain called paramedics and they met up us. Paramedics checked us all out upstairs; and took us all to the hospital were we all spent approximately 5 hours in ER.


Synopsis: An A320 developed a strong odor after takeoff; so the Captain asked the flight attendants to confirm cabin odor then returned immediately to the departure airport where paramedics suggested medical treatment for the crew.