A skylight was smashed in the atrium of First Canadian Place on Thursday afternoon when a construction worker dropped a tool from 40 storeys above the ground.

It came loose from a wrench while workers were assembling a scaffold on the 42nd floor of the downtown skyscraper. The socket bounced about 25 metres when it first landed and then hits a glass roof.

No one was injured. The accident occurred after the lunch hour so the area was less populated than it is at other parts of the day.

Officials with Ellis Don Construction are still investigating the incident. The company also says it plans to add additional layers of protection to the building to ensure no more windows are broken.