Three construction workers were killed and another injured yesterday in Raleigh, North Carolina when scaffolding on an 11-story building collapsed and fell into an adjoining parking lot.

News sources say the accident occurred when workers dismantled the scaffolding frame and began their descent down the side of a building. A subcontractor, Associated Scaffolding, was reportedly dismantling pieces that workers use to transport crews and materials to different locations.

WTVD-TV Raleigh reported that a platform fell from high up on the Charter Square building.

State Department of Labor spokesman Neal O'Briant said that his agency was investigating the cause of the collapse.

According to statistics from the state’s Department of Labor, there were 19 construction industry fatalities in 2014.