SEATTLE — On his first day back on the job, Chad Cook faced a truck driver’s worst nightmare: a runaway truck filled with broken concrete barreling down a city street.

Cook had just moments to react after his dump truck lost its brakes, plowing into a strip mall rather than continuing down Madison Street and possibly killing people.

“I thought I was going to die,” said Cook, 38, of Lake Stevens, who wasn’t injured in the accident. “I had no brakes. I had the pedal to the floor. I was screaming to myself, and I braced myself and let God take care of the rest.”

Cook said he lost his brakes at the top of a hill on Madison and was gaining speed, hitting three cars until it ran into a strip mall at the intersection of Madison and Martin Luther King Jr. Way. One driver was taken away by medics after being hit by Cook’s truck.

Police closed off the street while the accident was being investigated.

Cook said he intentionally drove into the building, which houses Madison Cleaners and Teriyaki Seven. After hitting the three cars — two occupied and one unoccupied — the truck hit a street sign and a Pizza Hut sign and then the roof of the building and was wedged into a cinder-block wall.

Stuart Monsma, of Seattle, was sitting in his car waiting to turn onto Martin Luther King Jr. Way when his car was struck by the truck.

“I could have been killed,” he said. “It was unbelievable.” He said he looked in his rear-view mirror and saw the truck barreling toward him at high speed. The truck clipped the driver’s side of the car, smashing it in.

Cook said he believed he was a hero because he didn’t just jump out of his truck and let it barrel down Madison. “I think I saved a lot of lives,” he said.

Cook had worked for the company, Les Wear Backhoe of Snohomish, three years ago, but quit. Today was his first day back on the job. He said he was following his boss, driving another truck, to a job in Seattle when he lost his brakes.