Date: 201211
Local time of day: 0601-1200
Location: ZZZ.ARTCC, US
Flight conditions: VMC
Light: Daylight
Aircraft: EMB ERJ 170/175 ER/LR
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Cruise; Climb; Parked
Airspace: Class A ZZZ
ATC / advisory: Center ZZZ
Aircraft component: APU
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: Pilot Flying; Captain
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Physiological - Other; Troubleshooting
Second reporter function: Flight Attendant In Charge; Flight Attendant (On Duty)
Anomaly: Aircraft Equipment Problem Less Severe; Flight Deck / Cabin / Aircraft Event Illness / Injury; Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor
Detector: Person Flight Attendant; Person Flight Crew
When detected: In-flight; Pre-flight
Result: Flight Crew Diverted; General Flight Cancelled / Delayed; General Maintenance Action
Contributing factors: Aircraft
Primary problem: Aircraft

Narrative: We reported early morning and received aircraft about twenty five minutes later. When we got on the aircraft the APU was running with the packs ON. We noticed an exhaust type smell which is not uncommon on these early morning originators due to smelly heat carts that are used overnight. We also suspected that it was possible that we were sucking in some exhaust from an outside source so I turned OFF the APU bleed for a while to clear the air. When we got ready to push I turned the APU bleed back ON and noticed that the smell had come back. I was concerned so I decided to go outside to see if there were any sources that could be causing the odor. I didn't see anything that was obvious so I decided to call Maintenance Control to discuss the situation. We came to the conclusion that since we had a slight tailwind; the odor could be caused from the APU exhausts getting blown back toward the intake. We decided to push back to see if the situation changed. We pushed back to deice; and after running all of the appropriate deice checklist we turned on the engine bleeds; and packs at the appropriate times and the smell did not return. We came to the conclusion that our assumption about the tailwind was correct and continued on with the flight. Shortly after takeoff; we started smelling a subtle odor. It was so light that we felt that it was either the system just clearing out some residual odor; or the odor just being stuck in our noses. As we continued on we noticed that the odor; still subtle; was not going away. We started to do some investigating as to what might be causing it. We noticed that the odor would increase as pack 1 would heat and would decrease as it cooled. During this time the flight attendants called to query about the odor. At that time we felt that Pack 1 might be the problem so I called Maintenance Control to see if there were any in-flight troubleshooting procedures we could go through to isolate the pack and possibly continue with the flight. Maintenance Control informed me that there was not; and to try to keep the pack from heating. He asked if we had a QRH procedure that would accomplish that and I informed him that there wasn't. At this time the odor was still so subtle that we felt that running the QRH procedure for smoke; fumes; or vapor would be a little much for the situation at that time. All we had was a subtle odor; and nothing that felt harmful at the time. I informed Maintenance Control that if we were not able to eliminate the odor that we were looking at diverting to have them investigate it. I ended the call at that point and asked Dispatch for numbers at FL310 in case we needed to turn off Pack 1. I called the flight attendants to see how the odor was in the back; and they informed me that it was still lingering and was worse toward the back of the aircraft. At this point I had made up my mind that we were going to divert. At about this time we received an ACARS message from Maintenance Control stating that they wanted us to divert too. We immediately joined up on the arrival and headed to divert airport. We informed ATC that we were having some issues but didn't feel that declaring an emergency was necessary because all we had at that point was just a subtle odor. As we continued the descent we noticed that odor was getting worse. Eventually the flight attendants called prior to 10;000 FT stating that it was indeed getting worse in the back; and that the B Flight Attendant was starting to feel a little ill. We requested and received 22L and landed shortly after the conversation with the flight attendants. We parked at the gate and deplaned the aircraft. No passenger complained about feeling ill at that time. Our two flight attendants said that they felt ill; and I myself was starting to feel ill. I handed the aircraft over to Maintenance to troubleshoot the problem. I went up to eat; and breathe some fresh air and started to feel better. I went down to talk to Maintenance and ended up hanging to help them try to find the problem. After Dispatch decided to cancel the flight; I left feeling ill again. I told the two maintenance guys to take a break that neither one of them looked very well. They both had extremely bloodshot eyes; and one of them said that he was not feeling well. When I got to the crew room I was not feeling well. I felt nauseous and kind of dazed. We got our assignment to deadhead. As we were headed to our deadhead the flight attendants were complaining about not feeling well. They informed me that I didn't look well; and I said that I didn't feel well. The First Officer said he felt fine; but I decided that since 3 of the 4 of us felt ill that it was probably a good idea to get checked out. At this point we contacted our supervisors and Scheduling and proceeded with the process of get checked out. One thing I think would help is to have in-flight troubleshooting procedures. Other airlines have this. If we had been able to do this we would have known sooner that we were having a problem that was not going to go away. A decision to divert sooner might have been made; however as [I] look back on it; I still feel that our divert airport was the best option all around given the circumstances.

Callback: The reporter had not heard any final decision about this event's cause. The initial thinking was some sort of a valve failure which caused hot air to be forced through it causing an overheated; chemical odor. The two maintenance personnel troubleshooting the systems became pretty ill. The reporter and his crew went to a medical clinic where three of them were diagnosed with upper respiratory and nasal irritation. One Flight Attendant and the reporter spent the night at the diversion airport; returned to medical the following day then cleared to travel home. The ill Flight Attendant is still off work with respiratory problems. The reporter was symptom free several days after the event.

Second narrative: Our crew waited for our aircraft to be brought to the gate. When we entered the aircraft we all noticed an odor. It smelled like jet fuel to me; so I was not alarmed; as it is pretty common to experience that type of odor at the gate. We did our normal pre-flight; and the Captain told us to start the boarding process. A woman passenger approached me and told me that her 18 year old; special needs daughter would be traveling with us; and that this would be her first flight on her own. I believe she was seated in 8C. She was not listed on my paperwork as needing special assistance; but I assured her mother that we would take good care of her. The mother wrote down her phone number and handed it to me before exiting the plane. We had a normal taxi; and take off; and I made my portable electronics announcement (and others) when the sign went off. I stood up from my jump seat; and went to my galley to begin my service. That is when I experienced a slight dizziness. I had some water; and began taking orders from first class passengers. When the B Flight Attendant finished setting up her cart in the aft galley; she called me and told me she was ready for me to come back and assist her in pushing/pulling the cart to the front of the cabin. I walked to the back of the aircraft; and about row 17; I smelled a very strong odor. It smelled chemical to me. When I approached the B Flight Attendant her eyes were very red. I asked her if she was OK; and if she smelled this same odor. She said she was; and that her eyes; throat; and nose were burning. I told her that I had been feeling a little dizzy; and that my nose was burning a little as well. B Flight Attendant and I immediately started looking for smoke or fire in the lavatory and behind the bins and carts. We did not find either thankfully; and I immediately went up front and called the flight deck to notify them that we still smelled that odor; and it seemed to be getting worse. I also told them that we did not see any smoke or fire. They informed me that they still smelled it too; and that they would get back to me shortly. We continued our cabin service; and the pilots were up front trying to figure out where the smell was coming from. We finished the service and just kept monitoring all areas of the aircraft; for anything out of the ordinary. The pilots called and notified me that we would be diverting to have the plane looked at and that they would make an announcement to passengers. I asked them if we should be preparing the cabin for an emergency landing; and they said no. I believe they said we would be landing in about 30 minutes. The other Flight Attendant and I then prepared the cabin and galleys for landing. Passengers were very cooperative and understanding of this diversion. I asked the 18 year old girl in 8C if she could wait in her seat for one of the flight attendants to walk her up to the gate after we landed. She said she would. After we landed and parked at the gate; my Captain asked everyone to remain on the aircraft for a few minutes until the mechanics took a look at the air conditioning. I informed the gate agents that I had a special needs passenger traveling on her own; and wrote down the mother's phone number; so that they could inform her that we had diverted. A Manager met the plane; and was very helpful to us. A few minutes later the Captain told everyone that we would be deplaning; and that they should bring their bags with them until we knew what was wrong with the air conditioning; and how lengthy this delay would be. I then walked the special needs passenger to the top of the jetway. We waited with the girl until we were sure that the gate agents had called her mother; and that they had a plan for her. The mechanics worked on the plane; and the flight ended up being canceled. (3 out of 4 crew members felt ill into the evening hours; and 1 of the mechanics mentioned he was not feeling well after being on the aircraft and smelling the fumes). The odor wasso strong it was all the way into the jetway.

Second callback: The reporter stated that the aircraft had been parked off the gate the night before and was tugged to the terminal with the APU ON. When she boarded the aircraft there was a slight chemical odor. The crew thought that once they were away from the gate and airborne the odor would dissipate. However; once airborne the odor became a burning chemical smell. The reporter and the other Flight Attendant (B) became ill during the flight; with the B Flight Attendant becoming much more ill than the reporter. At the gate; everyone deplaned but the crew left their bags on the aircraft until the flight was cancelled. Upon entering the jetway to remove their bags the reporter said she was overwhelmed by the odor which extended all the way to the terminal door. Talking with the mechanics later; she heard one say that they thought APU oil had gotten into the Pack and when heated caused the odor. The reporter stated that the Captain and B Flight Attendant both were very ill. The B Flight Attendant has not been cleared back to work as of this conversation; six weeks after the event.

Synopsis: An ERJ-170 diverted because of a very strong chemical odor in the cabin which was first detected during preflight but became very strong in flight. Three of the four crew members became ill.