Boeing faces a court trial related to air contamination in the passenger compartment.
Flight attendants filed a lawsuit against the company, calling it the "dirty little secret" in the cupboard of the airline business.
Flight attendants working on board of the 737 claim the company has always been aware of a risk of toxic fumes invading the passenger compartment.
Vanessa Woods says she and two other flight attendants passed out after a chemical odor filled the cabin on Alaska Airlines Flight 769.
"I felt like I might die," said Woods.
Currently nearly all commercial jets bleed fresh air in from the engines. It's then fed through an air conditioner and into the cabin, but if an engine seal fails, oil and other potentially toxic particles can be released.
Boeing would not comment on the lawsuit but in a statement said: "Based on solid research ... cabin air is safe to breathe ... contaminant levels are generally low and ... health and safety standards are met."
But lawyers for the four flight attendants released a 2007 email from a Boeing employee that said, "I think we are looking for a tombstone before anyone with any horsepower is going to take interest."
The FAA says cabin air is safe, but it is concerned that certain mechanical failures could lead to contaminants in cabin air.
Boeing's newest airplane - the 787 is the only one that does not bleed air from the engines.