One of two workers who fell out of an elevated man lift parked under the West Seattle Bridge has died.

The accident happened shortly early on a Friday morning.

The arm of the lift, which was raised at the time of the accident, was struck by a box truck traveling on an off-ramp. Both of the contractors were knocked out of the lift basket by the impact. One man was wearing a harness and fell about 15 feet, according to investigators.

Witness Hallie Guppy, drove by and saw the man still hanging in his safety harness.

“He looked like he was hanging and waiting, maybe kind of shocked. I don’t know,” said Guppy, who was on her way to work at the nearby Luna Park Café.

The second man fell all the way to the ground, about 50 feet, where the lift was parked under the bridge.

He later died at Harborview Medical Center.

Seattle police said the contractors were working on the Fauntleroy Expressway Bearing Pad Replacement Project.

The men were employed by C.A. Carey Corp. of Issaquah, and worked as contractors for SDOT.

Washington State Department of Labor and Industries and the Occupational Safety Health Administration are investigating. The investigation could take six months.

Seattle police interviewed the driver of the box truck and had no reason to believe he was impaired. He will be tested to see if he was driving under the influence of drugs or alcohol, which is routine after a deadly accident. Investigators will try to determine who is to blame.

"Were they where they were supposed to be? Was it signed properly? Were there cones? Did they do everything possible to avoid this?" said SPD Detective Patrick Michaud. He said interviewing the survivor should help the investigation.

The worker who survived was in serious condition and had surgery at Harborview Medical Center on Friday.