(BIVN) – 22 passengers were sent to the hospital after the Hawaiʻi County Hele-on bus they were riding rolled backwards through a guardrail on Māmalahoa Highway along the Hāmākua coast Tuesday morning.

The traffic crash occurred at the Laupāhoehoe Scenic Lookout.

The Hawaiʻi Police Department described the incident in a news release:

At 4:56 a.m., Hāmākua patrol officers responded to the area of the 25.5 mile marker after a bus went through a guardrail down an embankment on the makai, ocean side, of the highway.

Police determined that the bus had stopped at the Laupāhoehoe Scenic Lookout to pick up passengers. The driver, a 66-year-old Hilo man, reported that he had placed the bus in park and walked toward the rear of the vehicle to check for available seating, when the bus began rolling backwards onto the highway, went through a guardrail, and down an embankment, coming to rest on its passenger side.

Hawai‘i Fire Department personnel examined the driver and 22 passengers at the scene. All 22 passengers were transported by multiple ambulances to Hilo Benioff Medical Center for further evaluation. The most serious injury reported was a minor laceration to the hand of an elderly male passenger.

Police say the investigation remains ongoing at this time.

Highway 19 at mile marker 25 was closed in both directions for a few hours Tuesday morning due to the incident.