[article] (CNN) -- Passengers aboard US Airways Flight 2846 were waiting on the tarmac at Phoenix's Sky Harbor Airport when their pilot came on the intercom. "We've been notified about a health emergency aboard the aircraft," passenger Dean Davidson heard. A few minutes later, Davidson saw a flight attendant walk toward another passenger sitting a few rows ahead of him. The flight attendant handed the slender middle-aged man a medical mask. Emergency personnel boarded the plane a short time later and removed the man, Davidson said. A firefighter then came on the intercom and announced that the passenger had active tuberculosis and was contagious and that other passengers on the flight had been exposed. He advised them to contact their physicians immediately, Davidson said. The US Airways flight took off from Austin, Texas, on Friday, according to airline spokesman Bill McGlashen. It landed in Phoenix approximately two hours later on a layover before it was scheduled to fly to Los Angeles. There was no warning or flag on the passenger's record when he was going through security or when he boarded the plane, McGlashen said. After the plane took off, the Centers for Disease Control and Prevention notified the Transportation Security Administration of a possible risk. The TSA then notified US Airways, McGlashen said. More info here.