The lawsuit seeks "tens of millions" of dollars for up to 4,000 flight attendants forced to breathe tobacco smoke on long flights for years after the airline banned smoking on domestic flights and in its corporate offices.
The high court rejected an appeal by the Minneapolis-based Northwest, arguing that a federal law preempts the state law under which the personal injury lawsuit had been brought. Three of the nine high court members dissented.
The lawsuit was filed by Julie Duncan, a longtime Northwest flight attendant, in 1998. At that time, Northwest banned smoking on U.S. and many international flights but, consistent with federal regulations, allowed it on some Asian flights.
Northwest said it permitted smoking to compete with foreign air carriers that allowed it on the same routes. While the case was pending, Northwest decided to ban smoking on all flights.
The lawsuit, which also seeks medical monitoring, claimed Northwest breached its duty under state law to provide a safe and healthy work environment for its employees.
A federal judge in Washington state had dismissed the lawsuit, ruling that the 1978 Airline Deregulation Act preempts lawsuits under state laws relating to airlines' "rates, routes, or service."
But a U.S. appeals court in April reinstated the lawsuit. It said permitting smoking does not fall under "service," and that allowing smoking and offering in-flight beverages would better be described as "amenities."
Northwest argued that the appeals court erred when it held that a state may regulate any "service" provided on an international or interstate flight if it does not involve price or route determinations.
In its Supreme Court appeal, Northwest warned the ruling will result in "a checkerboard of state regulation, requiring airlines to vary their policies from place to place as they attempt to compete for passengers."
Duncan's lawyers replied that Supreme Court review of the case was unwarranted.
They said that exposing airlines to liability for personal injury claims does not contradict what Congress intended in adopting the deregulation law.
The high court's action cleared the way for the case to go back to the federal judge for more pretrial proceedings.
Justice Sandra Day O'Connor, joined by Chief Justice William Rehnquist and Justice Clarence Thomas, dissented. She said the case presented an important issue that has divided federal appeals courts across the country.
O'Connor said she would hear and decide the case to "bring certainty to this area of the law" and to bring "needed certainty to airline companies."
In other action Monday, the U.S. Supreme Court:
- declined to hear a case testing whether a murder suspct's confession, made after he was read his Miranda rights, was tainted by lengthy police questioning and incrimination statements he had made earlier. Martin Tankleff of Long Island, New York, who was eventually convicted of killing his parents, was 17 at the time of the attack. He claims he should have been read his rights earlier than was the case.
- agreed to use a rival boxing promoter's lawsuit against Don King to clarify when people can be sued for allegedly conducting racketeering activity through a business. The court said it will hear the argument from Cedric Kushner Promotions that it should be allowed to pursue such a claim against King.
- agreed to clarify when some inmates can file federal court appeals arguing that their trial jury instructions were improper. The justices will hear the case of Louisiana inmate Melvin Tyler, who is serving a life sentence for the murder of his teen-aged daughter.
CBS Worldwide Inc. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed. The Associated Press contributed to this report