Stairwell collapses at DTLA construction site, injuring worker

LOS ANGELES - A worker was injured after a stairwell collapsed at a construction site Thursday. 

Firefighters responded to the 200 block of West Olympic Boulevard in downtown LA around 11:30 a.m. after receiving reports of a collapsed structure.

Image of construction site from SkyFOX

Officials say a subterranean stairwell collapsed, trapping one worker underneath. Crews were able to quickly free the man, and he was transported to a hospital with serious injuries. No one else was injured. 

It's unknown what caused the stairwell to collapse.