A320
Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Physiological - Other; Situational Awareness
Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor
Flight Crew Landed As Precaution; Flight Crew Returned To Departure Airport; General Maintenance Action
Aircraft
Cabin crew reported odor; fumes of a chemical nature very strong in back of plane. Pilots smelled 'dirty socks' and donned oxygen masks. We determined it strong enough to return to ZZZ. We were vectored back to an arrival and landed without incident; and did not declare an emergency.
On the climbout the flight attendants called up front and told us they could smell an odor. I was pilot flying so the Captain did all communicating with the flight attendants. We had a brief conversation and did not notice anything too bad at that time. Flight attendants called back again a couple min later and reported having headaches due to the dirty sock smell which escalated to more of a chemical smell in their opinion. We donned our oxygen masks and Captain accomplished QRH procedures as I was flying and working the radios. The Captain decided to divert back to ZZZ. We proceeded back to ZZZ while our masks were on and flew the ILS to XXL...I kept my mask on to the gate and the flight ended without any more issues.
A320 flight crew reported chemical fumes in cabin noticed by flight attendants. Subsequently; odor was detected in the flight deck. Flight crew executed a precautionary return to departure airport.