Seven skiers at a Maine resort were injured after a chairlift stopped and began sliding backward down the mountain, officials and witnesses said.

Four people were taken to a hospital from Sugarloaf Mountain Resort, though none are believed to have life-threatening injuries, resort spokesman Ethan Austin said.

"It was really scary," said David Segre, 42, of Falmouth, who was standing in the crowded lift line. "It was like a gear had let loose and it was slowly picking up speed going the wrong way."

"So all the chairs ... they were slipping backward. And as gravity works they started to go faster and faster and people were jumping off at the lower levels," he said.

The accident is the second chairlift incident at Sugarloaf in the last five years. Eight skiers were hurt in 2010 when a chairlift derailed causing five chairs to fall 25 to 35 feet to the ground.

Resort officials said Saturday’s accident was a “rollback” that carried riders backward about 450 feet.

Mark Di Nola, a ski safety consultant based in Manchester, New Hampshire, said it's unusual to have two lift accidents of this magnitude in five years, and such a "rollback" is rare in the ski industry.

"The industry is aware of issues involved in the continued use of aging ski lifts, in this case 37 years. Analogous to our country's aging infrastructure of roads and bridges," he said in an emailed statement.

One man who was unable to jump ended up going around the loading area and heading up the mountain on the other side, Segre said.

The injured skiers were treated by ski patrol and taken off the mountain to be treated by medical personnel responders, Austin said.

About 230 people were riding the King Pine quad lift at the time of the accident, officials said. Those still on board after the lift was stopped were evacuated, a process that took about two hours.

The 3,400-foot chairlift receives routine daily inspections for safety, Austin said. It passed state inspection on Oct. 29.

''Our staff is working with the Tramway Board on a thorough investigation, and we are committed to understanding the full cause of today's incident," he said. An inspector from State of Maine Board of Elevator and Tramway Safety was on site.

The Associated Press contributed to this report.