Drone video from the Fontanka news agency appeared to show the worker failing to get into a crane cradle as the sports complex begins to collapse on January 31. A second worker appears to be seen in the cradle and escaped alive.
The Russian Emergency Situations Ministry said more workers could be trapped under the rubble and a search was under way.
Workers were clearing the site of the St. Petersburg Sports and Concert Complex to make way for what is being billed as the world’s largest ice arena.
The workers were cutting structures that connected the roof of the arena to its walls when it collapsed.
The stadium was built in 1979 and was considered unique because of its 56 columns that held up the structure. Local activists had been campaigning to save it. They had tried to get it registered as a historical site, but their efforts were rebuffed on account that the structure was not 40 years old, but 39, when they applied last year.