Date: 201307
Local time of day: 0601-1200
Location: ZZZ.Airport, US
Aircraft: B737-800
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Climb
Airspace: Class B ZZZ
ATC / advisory: Tower ZZZ
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Troubleshooting
Second reporter function: Pilot Not Flying; Captain
Anomaly: Aircraft Equipment Problem Critical; Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor; Flight Deck / Cabin / Aircraft Event Illness / Injury
Detector: Person Flight Attendant
When detected: In-flight
Result: Flight Crew Landed in Emergency Condition; Flight Crew Took Evasive Action; Flight Crew Diverted; General Physical Injury / Incapacitation; General Declared Emergency
Contributing factors: Aircraft; Human Factors
Primary problem: Ambiguous

Narrative: During climbout we got an initial report from the flight attendants in the aft galley of a strange smell/odor like electric or oil. We advised the flight attendants to turn off all ovens as a precaution; and then asked if the smell/odor dissipated after a while. After a short while; one Flight Attendant reported being light headed and dizzy; then later was nauseated. Eventually this Flight Attendant had to be seated and was tended to by an on board physician with oxygen. A little while later a second Flight Attendant was reported as having the same symptoms and was treated similarly. At that point we turned off power to the aft galley using our switch on the overhead panel. We also advised ATC of a possible medical emergency involving flight attendants on board. After both flight attendants received oxygen; they were reported to be improving physically for a short time. Some time later a third Flight Attendant was reported as having similar symptoms and one of the other flight attendants had passed out. We decided at that point to divert for medical assistance. We advised ATC of our intentions and we were cleared direct to the divert airport. On short final to land 2 of the flight attendants were reported to have passed out. We proceeded to our gate after landing and paramedics met the aircraft to remove all of our flight attendants and transport them to the hospital for treatment. Cause is unknown at this time. Neither pilot was affected by the odor/smell from the flight deck. We could not smell it at that part of the aircraft.


Second narrative: Flight attendant incapacitation from unknown cause leading to a medical diversion. Climbing through FL260; aft Flight Attendant complained of possible burning smell in aft galley area. I directed all ovens turned off and galley power was subsequently removed. At FL320; B Flight Attendant complained of feeling slightly light headed and some dizziness. I directed her to remain seated and asked the other flight attendants to assess. Aft cabin flight attendants continued to complain of a mild odor that they described as an oily smell; so I directed them to look for possible spills in overhead bins from passenger bags; and other areas of the cabin that could explain any unusual odors. Approximately 30 minutes into the flight a second main cabin (C) Flight Attendant began to feel symptoms of dizziness and the B Flight Attendant became more ill; possibly loosing consciousness for some period of time. I contacted Dispatch via SATCOM and advised of our situation and discussed possible divert options. Maintenance Control was advised; but they were not able to provide any possible solutions. I was patched to MedLink and began the process of treating the B Flight Attendant with O2 and apple juice to which she responded positively; but still felt ill. I asked the C Flight Attendant to remain seated and she was also administered O2. We had an ER physician on board who was very helpful to the sick flight attendants and in advising me of the situation and he was the main contact with MedLink on the headset. I declared a medical emergency with ATC shortly after when I began the process of talking on SATCOM to Dispatch and MedLink. I told ATC that I felt it prudent to declare the emergency due to all of the distractions in the flight deck that could lead to a missed radio call. I asked ATC to keep an eye on us while we sorted out the problem. The process with MedLink was ongoing and they advised me to continue the flight to [our destination] and call back if the B Flight Attendant's condition changed. MedLink and the physician on board were satisfied that the condition of my sick Flight Attendant was not serious.I spoke in length to the physician and he was not able to smell any odors and he felt fine and did not observe any passengers who looked ill and no passenger complained of any problems. My A Flight Attendant called to complain of a possible oily smell in the front of the cabin and said she was feeling a little dizzy and light headed. I directed her to cease her service and sit down. She continued her service for some time; but then asked the D Flight Attendant to come to the front while she went to the back. Shortly after that the A Flight Attendant became ill with symptoms of dizziness; light headedness; burning throat and may have lost consciousness for a period of time. At this point I had one Flight Attendant who was able to perform her duties; two flight attendants who were incapacitated and one Flight Attendant who was feeling ill. The source of the illnesses was not clear; whether a problem with the aircraft of other physiological cause; but my flight attendants' conditions were getting worse and could not be resolved quickly in flight. I initiated a medical divert which gave me 10 minutes to arrange the divert; check performance for the overweight landing; coordinate medical response and brief the divert with my First Officer who remained the pilot flying. I briefed the passengers what we were doing; that the aircraft was completely safe and that we were diverting due to three flight attendants being ill. The diversion was uneventful and all normal procedures were accomplished; normal airspeeds flown and we flew a normal visual approach to XXL and retained our medical emergency status to the gate. We were met by emergency medical responders and the three flight attendants were taken to a Hospital ER and treated for their symptoms and were released. I wrote up the overweight landing and the possible air quality event in the Maintenance logbook; spoke to local Maintenance technicians and secured the aircraft.Unknown cause for three flight attendants becoming ill in flight. All four flight attendants thought that they smelled an odor that was best described as an oily smell that seemed to be more discernible in the aft end of the aircraft (aft of row 23). It is unknown whether the incapacitation of the two flight attendants and illness of the third was due to aircraft malfunction or other physiological causes.


Synopsis: Three B737-800 flight attendants became ill in flight from what was described by them as an oily smell; so the flight diverted to an enroute airport where medical examinations was administered.