A DART bus partially entered a “construction excavation” after part of a roadway gave way on Harry Hines Boulevard early Thursday, sending 15 passengers to area hospitals, officials said.

The incident happened about 6 a.m. near Harry Hines Boulevard and Exchange Avenue, DART said in a statement. Dallas Fire-Rescue said a metal plate shifted and exposed a hole along the 6300 block of Harry Hines Boulevard.

There were 18 passengers on the bus at the time, DART said. Fifteen of them were taken to hospitals for evaluation and treatment, and three declined medical attention at the scene, authorities said. All reported injuries were believed to be minor, according to DART.

Dallas Fire-Rescue dispatched several units, including seven rescues and an EMS supervisor, to assist at the scene. Patients were taken to Parkland Memorial Hospital, Baylor Scott & White Medical Center and Methodist Dallas Medical Center, according to the fire department.

“The safety of our passengers, employees, and the public remains DART’s highest priority,” the agency said. “DART is working closely with Dallas Fire-Rescue, the Dallas Police Department, and other responding agencies as they investigate the incident.”