PORTLAND, Ore. -- A large rock fell from a Portland overpass and smashed through the cab window of a mail truck Tuesday, injuring the driver.

Thomas Bennett was traveling eastbound along Interstate 84 when the large U.S. Postal Service truck was suddenly hit by the rock under the Northeast 28th Avenue overpass.

“Glass flying in my face, my chest getting hit by a boulder, at first I thought it was a shotgun blast," said Bennett. "I was checking my shirt to see if it was wet so I wasn’t shot.”

Responding officers collected the rock as evidence. They noted that it weighed just under 4 pounds.

Officers also searched along the overpass for any additional clues. No suspects were found.

Thomas Bennett shows an injury to his face.
Thomas Bennett shows an injury to his face.

Bennett's injuries were not life-threatening. He is now recovering at home in Salem, on disability from work.

“They flushed out my eyes out three times, they did a cat-scan and found they didn’t get all the glass out, they had to go back and get the glass out of my left eye,” he said.

USPS officials said they were still able to make sure the mail was delivered on time, even after the accident.

Photos: Damage from rock falling onto mail truck