By Jim Gold, msnbc.com reporter

A health issue as old as jet air travel took off anew this week with Boeing Co. settling a lawsuit brought by a former American Airlines flight attendant.

Terry Williams, a 42-year-old mother of two, accused the company of faulty airplane design that left her suffering disabling health woes after breathing toxic jet oil fumes that entered the cabin of an American Airlines MD-80’s air conditioning system.

The fact that oil fumes, often carrying a "dirty socks" odor, have leaked into cockpits and cabins on rare occasions ever since jet airplane designers decided to use systems that draw — or "bleed" -- air from jet engines is not in dispute.

As early as 1953, Boeing issued a "Decontamination Program" report based on a study of bleed air in B-52 flights.

"The possible toxic effect of the contamination is still unknown," noted  the report, which was turned over to Williams' legal team during the discovery process. "As a result, except for specific instances, the crew used 100% oxygen throughout all flights and made their observations by removing their masks for a moment or two."

It also said the odor "permeates the nasal passages of the men, their clothing, oxygen masks, cabin lining, etc., and lingers for a substantial period of time after exposure occurs."

Despite industry acknowledgement that contaminated air occasionally breaches airliner cabins when seals fail, they have long asserted publicly that "cabin air is safe," saying such exposures are rare and would not produce long term health effects.

Pilots, flight attendants and even some passengers who claim the fumes have left them with long-term ailments like tremors, memory loss, dizziness, disorientation,  headaches and fatigue have had tough times proving their cases. And some crew members who have lost their jobs, allegedly due to ailments from fumes, claim the airline industry and many regulators have covered up the issue and understated the severity of the problem.

Click here to read the full story about Wednesday’s settlement and the long-running debate over the safety of jetliner cabin air.