Emergency personnel believe that an employee at a commercial warehouse whose roof collapsed is trapped under a 40- to 50-foot pile of debris, officials said.

The collapse occurred about 10 p.m. Thursday at a warehouse at 1501 Cabin Branch Drive in Landover. Employees told firefighters that a forklift accidentally struck a storage rack, which fell, leading to other racks and support beams being hit. The roof collapsed after support beams fell, and the walls buckled, according to the Prince George’s County Fire/EMS Department.