An F-16 fighter jet crashed Thursday into a warehouse just outside March Air Reserve Base in California, sending a dozen people to hospitals for evaluation after they were exposed to debris, authorities said, AP reports.

The pilot ejected and parachuted to safety, said Maj. Perry Covington, the base’s director of public affairs. The cause of the crash was under investigation.

Interstate 215, which runs between the base and the warehouse, was closed in both directions, backing up rush-hour traffic for miles.

Television news showed a large hole in the roof and sprinklers on inside the building about 65 miles (105 kilometers) east of Los Angeles.

Cellphone photos and video from inside showed what appeared to be the tail of the plane buried in twisted metal and piles of cardboard boxes.

Daniel Gallegos, a warehouse worker, said he’s used to hearing the sound of planes coming and going, but the noise just before the crash was deafening.

“Next thing I know I just hear this explosion and turn around to the back of the building, and I just seen a burst of flames and just the ceiling started falling through every part of the building,” he told KABC-TV . “I turned around, and my co-worker just told me to get out, so I just made a run for it.”