Soon after her flight took off from Charlotte-Douglas in 2009, Amelia McCarthy knew something was wrong.
"I got a whiff of a smell that was different from any other plane I have ever been on," McCarthy said.
Her four-hour flight to San Juan felt much longer.
"My stomach felt weird," she said. "I was breathing very hard, like short of breath."
Fourteen US Airways crew members and other passengers claim they got sick from that same plane. Now the crew members are suing Alabama-based ST Aerospace Mobile, the maintenance facility that worked on the plane. They think contaminated air from the plane made them sick.
It's called bleed air because it "bleeds" off the engines into the cabin. The engine oil contains a toxin that can cause neurological damage.
Dr. Robert Harrison is an occupational specialist who treats patients exposed to contaminated bleed air. He told Eyewitness News about some of the symptoms it can cause.
"Headaches, dizziness, nausea, shortness of breath, difficulty concentrating," Harrison said.
He has spent more than a decade researching those contamination events.
"They probably occur hundreds or thousands of times each year aboard aircraft worldwide," he said.
However, there is no standard reporting system for these events, and airlines are not required to tell passengers when they happen. The FAA may soon work on changing that. But for now, since many passengers do not know very much about the issue, they may be unlikely to report health problems.
Harrison said some of those symptoms can become chronic. In fact, crew members from various airlines have reported chronic symptoms after bleed air contamination events. Some have not been cleared to return back to work.
US Airways operates 90 percent of the flights at Charlotte-Douglas. Its VP of Safety and Regulatory Compliance, Captain Paul Morell, said bleed air contamination incidents are rare.
Since October of 2007, the FAA said US Airways has filed 33 reports of service problems because of fumes.
Morell said cabin odor events are not always caused by toxic fumes. They can stem from dirty ovens, trash, fans, or more.
The airline tracks and reviews all the events. Morell said to prevent future problems, the airline has changed how it services certain parts of the airplane, it performs some inspections more often, it has developed a "bleed air analysis tool" to diagnose where contamination may have originated, and is working with manufacturers to research new filters for planes.
Morell said the scientists that work with US Airways found these incidents are not as serious as some think.
"They have determined there are no long-term effects from being exposed to any type of odor event on our airplanes or any airplanes that are out there," he said.
But McCarthy said she still has problems, two years after her flight to San Juan.
"The balance problem, the short breathing, the exhaustion are still there," she said.
McCarthy wants airlines to be forced to contact passengers onboard flights with documented air contamination issues.
"They could be out there suffering and they don't know what's causing it," she said.
McCarthy said she suffers from symptoms every day, and she hopes the airline industry takes action soon for the sake of other passengers.
A bill currently in Congress would give the FAA money to study air quality issues on planes, develop a reporting standard for fume events, and look at whether bleed air filters should be installed on planes, among other things. However, the bill is stalled right now and lawmakers aren't optimistic that it will pass soon.