The flight attendants had served dinner, and only about two hours remained on the Continental Airlines nine-hour transatlantic flight when Gail Barnard-Boyum headed for the restroom.

"The toilet was full," recalled Barnard-Boyum, 66, of Peterson, Minn. "You could see the toilet paper. You could see the poop. I couldn't believe it because the smell was so disgusting."

Barnard-Boyum and 13 other Minnesotans were heading home Sept. 14 from Barcelona after a Mediterranean cruise. They discovered that all three toilets in coach class on Flight 121Y were backing up. Some passengers used them anyway. Others refused, and rushed off the plane to find a restroom when it landed in Newark, N.J.

"We were not happy with the experience," said Sharon Sorenson, 68, of St. Michael, Minn. "I am not anxious to fly Continental again."

When contacted by Whistleblower, United/Continental Airlines spokesman Charlie Hobart acknowledged the inconvenience by offering $100 vouchers to affected passengers.

If the toilet malfunction had happened while the plane was stuck on the runway, Continental might have been in violation of federal rules. But there's no similar rule for airplanes with toilet failures in flight.

"To me, it is a bad situation that hasn't been addressed," said Robert Brubaker of the American Restroom Association, a Baltimore-based advocacy group for toilet users.

Of the 14 Minnesotans on the flight, 11 were from Coldwater Creek Townhome Association in St. Michael, including Sharon McDonald, 69, who coordinated the trip. She said if there was an operating toilet, it was in first class, because none of the three in coach were operating. The sister of Barnard-Boyum, she said coach passengers were not allowed to go to the first-class section's toilet.

McDonald said one of the flight attendants told her the problem had happened before and that the toilets may not have been emptied before it took off from Barcelona.

But Hobart, the airline spokesman, said the toilets aboard the flight were properly serviced in Barcelona. All four lavatories on board were "fully functional" but three were filled by the time it landed in Newark, he said. "We understand this was a frustrating experience and it does not reflect what we aim to deliver to our customers," Hobart said.

Carol Menier, 64, said when she called to complain, Continental's representative was "rude" and expressed doubts that the toilets were full and that another passenger was offered a $100 voucher. She eventually got a voucher and said another customer service agent was "really great."

The toilet travail wasn't the first for a Continental transatlantic flight. In 2007, a toilet overflowed on a flight from Amsterdam to Newark, spilling sewage down the aisle, USA Today reported at the time.

Brubaker, of the restroom association, said occasionally he hears of commercial airliners with toilets that do not work. Toilet facilities are required for employees under federal labor regulations, so while flight attendants and pilots can complain to the federal Occupational Safety and Health Administration, passengers have no recourse, he said. He said the U.S. Department of Health and Human Services, which has a mandate to protect public health, should step in.

The Federal Aviation Administration has no jurisdiction over airplane toilets, said Arlene Salac, an agency spokeswoman. She referred Whistleblower to the U.S. Department of Transportation.

Bill Mosley, a DOT spokesman, said there's a new consumer rule that requires carriers ensure lavatories are operable during long tarmac delays. But he said, "There is no federal regulation requiring working lavatories aboard aircraft in flight."

Randy Furst • 612-673-4224