Communication Breakdown; Other / Unknown
Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Hazardous Material Violation; Flight Deck / Cabin / Aircraft Event Passenger Misconduct
Air Traffic Control Provided Assistance; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Returned To Gate; General Maintenance Action
Human Factors
Received communication from Operations that flight ZZZ to ZZZ1 was coming back to [the] gate because a customer had O2 oxygen tanks not approved for flying.  Went onboard to investigate customer who was traveling with her infant.  The oxygen bottles were for the infant.  I asked if the baby could fly without oxygen.  Customer assured me that yes; the baby could fly; the oxygen was for tonight at bed time when she arrived in ZZZ1.  I advised customer of our policy and that these canisters could not fly.  Customer advised me that both she and the baby and the oxygen all flew in from ZZZ2.  I relayed our policy and advised her that I would take the oxygen down to baggage claim area. Passenger had two full canisters in a black roller board bag; and the 3rd O2 container was in a small pouch with a shoulder strap that easily looked like a shoulder strap purse.  The CSR boarding the aircraft was senior and did not notice any discrepancies that may have alerted her to the fact that there was oxygen canisters being transported.  Once the plane pushed off the jet bridge the flight attendant onboard witnessed the customer with the O2 bottle and inquired about it. Baggage Service is advised and has customer's phone contact; but bottles cannot be flown; customer will need to make arrangements in ZZZ1 for the babies oxygen tonight.  Will also follow up with a report on how the oxygen canisters made it through TSA in ZZZ2 undetected.
Ground Agent reported notification of aircraft ground gate return to remove unauthorized oxygen canister.