Two more passengers who survived a bus crash that killed nine others on an Oregon highway have filed a lawsuit against the tour bus company and the driver.

June Won Kim and his wife Hee Eun Kim, of Burnaby, B.C., said in their notice of civil claim that the bus was mechanically defective and the tires were inadequate for the road conditions on Dec. 30, when the vehicle crashed through a guardrail on Interstate 84 and tumbled down a snowy embankment near Pendleton, Ore.

The couple allege in separate B.C. Supreme Court documents that Mi Joo Tour and Travel failed to equip the bus with proper headlights, windshield wipers and warning devices to ensure it could be safely operated on the trip from Las Vegas to Vancouver.

The Kims also alleged the driver, from Surrey, B.C., was too tired, speeding, failed to obey road signs and operated a vehicle contrary to restrictions on his driver's licence.

The couple say they both suffered a brain injury, a collapsed lung, and back and neck injuries resulting in permanent disability.   

June Won Kim, a dental technician, said he also suffered permanent injuries to his face, hand, knee, feet and teeth.

His wife's shoulders, eyes and legs were injured and she is dealing with anxiety issues, her lawsuit said.

Company blames black ice

The B.C. couple's lawsuit followed another by two Korean exchange students in Tacoma, Wash., who said they witnessed a nightmarish scene on bus as they lay among dead passengers while the injured were screaming and crying.

Jong-Hyun Chae and Seong-June An, along with the Kims, were among 38 people injured on the bus on a stretch called Deadman Pass.

The driver was also hurt.

However, a lawyer for the bus company has said black ice, not driver fatigue, led to the crash in an area that has a history of traffic accidents.

Mark Scheer said the driver had seven and a half hours' sleep before the crash and had rest break during the two and a half hours he'd been on the road.