MOUNT DESERT – A passenger riding in a pickup truck was taken to the hospital in critical condition Monday evening after the vehicle hit a utility pole on Route 102 and knocked out power for almost six hours to most of the western half of Mount Desert Island.

Passenger Kevin Chipman, 26, of Southwest Harbor suffered facial lacerations and a broken jaw during the 5:40 p.m. accident, which took place near the Southwest Harbor-Mount Desert town line.

His condition was upgraded to stable upon arrival at Mount Desert Island Hospital, police officials said, and he was transported to Eastern Maine Medical Center in Bangor at 3 a.m. He was still in stable condition there late Tuesday afternoon.

“He’s in a lot of pain. He’s going in for surgery in the morning,” his sister, Michelle Chipman of Southwest Harbor, said Tuesday.

Kevin Chipman was conscious and talking, his sister said.

A bone from her brother’s broken jaw was lodged in his skull, Chipman said, and surgeons will attempt to remove that bone.

The 1996 Dodge Dakota truck was driven by Leon Jacobs, 32, of Bernard. He suffered a bruised chest, bruised ribs and knees, and a sprained left ankle. He was transported to Mount Desert Island Hospital immediately after the accident but was released later that night.

The cause of the accident is under investigation, police said, but alcohol is not considered to be a factor. The truck’s speed is not yet known, but the speed limit is 50 mph on that section of the road.

“Chipman was not wearing a seat belt,” Officer Chris Smith of the Mount Desert Police Department said Tuesday. “Jacobs was wearing the shoulder belt portion of his seat belt.”

Smith attributed Jacobs’ lesser injuries to his partially-worn seat belt and to the driver’s-side air bag, which deployed during the crash. There was no passenger-side air bag in the truck, which was destroyed in the accident, according to the officer.

“There was serious front-end damage as a result of collision with the pole,” Smith said.

When officers arrived at the scene, Chipman and Jacobs had already gotten out of the truck, which lay entangled in a pile of live electrical and telephone wires. More low-hanging wires were dangerously close to the roadway. Officers surmised that the men escaped from the vehicle by themselves.

The accident was reported to police by passing motorists, some of whom also assisted the injured men. An emergency medical technician who happened to be driving by helped care for them and another motorist let the more gravely injured Chipman sit inside his car.

Police diverted traffic away from the accident scene from 6:30 until about 11 p.m. Crews from Bangor Hydro-Electric Co. removed the broken utility pole and replaced it with a new one, Smith said.

Power was restored to Southwest Harbor, the Cranberry Isles, Swans Island, Tremont and Mount Desert at 11:20 p.m., the officer said.