Two construction workers fell to their deaths when scaffolding collapsed above the sixth floor of a hotel under construction near Disney World early Wednesday. A third worker managed to hang on and climb to safety, a fire-rescue spokesman said.

The accident happened just outside Disney property, Orange County Fire Rescue spokesman Mike Jachles said.

“They were on the scaffolding, and for reasons unknown at this time, that support structure gave way, sending two workers plummeting to the ground below. Both died on the scene. A third worker managed to hang onto the scaffolding and managed to climb to safety,” Jachles told The Associated Press.

Marriott International has described the project as a 16-story, $282 million JW Marriott Orlando Bonnet Creek Resort, featuring 516 rooms near Orlando’s popular theme parks. It’s owned and developed by DCS Investment Holdings, a private equity group based in West Palm Beach, Florida, which is owned by Dwight C. Schar, co-owner of the Washington Redskins.

Fire-Rescue got the call at about 4:15 a.m., when about 18 workers were at the scene.

Jachles said it happened at the top of the construction project, which is still in the concrete-pouring stage. The Orange County Sheriff’s office and the U.S. Occupational Safety and Health Administration will investigate, he said.