SEATTLE - Black ice, not driver fatigue, was responsible for a deadly bus crash that killed nine people in Oregon, says the lawyer for the Vancouver tour company operating the vehicle.

One day after the U.S. Department of Transportation pulled Mi Joo Tour & Travel Ltd.'s authority to operate south of the border, company lawyer Mark Scheer held a press conference in Seattle, Wash., explaining why the tragedy occurred near the northeast Oregon community of Pendleton.

Nine people died and 38 were injured Dec. 30 when the tour bus travelling westbound in the left lane of Interstate 84, hit a concrete barrier, veered across both westbound lanes and went through the guardrail, plunging about 60 metres down an embankment.

"Black ice was a significant factor in the cause of the accident," said Scheer Wednesday evening. "It appears that the area in question near Pendleton, Ore., ... has a history of traffic incidents, and there were other accidents in the area close to this one involving black ice on Dec. 30, 2012."

Scheer said the bus driver, Haeng Hwang, had about seven and a half hours of sleep the night before the crash, and that morning had only been on the road for about two and a half hours, including a rest break.

He said the bus driver had a good safety record, is in good health, doesn't use alcohol or tobacco, and there is no evidence to suggest alcohol or drugs played any role in the crash.

On Tuesday, the U.S. Department of Transportation filed an "imminent hazard" order, alleging the company doesn't ensure drivers are properly rested.

A federal investigation found the driver had been on duty for 92 hours during the eight days before the accident and had exceeded a 70-hour federal limit.

Scheer said he and the company are concerned by some of the issues reported in the media and in the findings of the U.S. Department of Transportation.

He said the company had just received the federal report and had not yet responded to the order.

"It has every intention of complying to DOT orders, of course, but there is concern about it, and we'll be looking at that closely."

A spokeswoman for the B.C. Transportation Ministry said Wednesday it was helping the U.S. government with its safety audit and is conducting its own investigation into the company, with the results expected shortly.

In Canada, each province is responsible for carrier safety and vehicle inspections.

Before the accident in Oregon, Mi Joo Tour and Travel had maintained a satisfactory safety rating in B.C.

— By Keven Drews in Vancouver

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  • A piece of heavy equipment strains to move a bus which plummeted 200 feet down an embankment in rural Eastern Oregon Sunday, <a href="http://www.huffingtonpost.ca/2013/01/01/oregon-bus-crash_n_2392360.html">killing nine and sending multiple to hospitals</a>.

  • Workmen move the bus which plummeted 200 feet down an embankment in rural Eastern Oregon Sunday, <a href="http://www.huffingtonpost.ca/2013/01/01/oregon-bus-crash_n_2392360.html">killing nine and sending multiple to hospitals</a>.

  • Emergency personnel respond to the scene of a multiple-fatality accident after a tour bus careened through a guardrail along an icy highway and fell several hundred feet down a steep embankment.

  • Jaemin Seo, 23, a Korean student from Vancouver, B.C., speaks about waking up to people screaming and then being thrown from a <a href="http://www.huffingtonpost.ca/2013/01/01/oregon-bus-crash_n_2392360.html">bus that crashed</a> in rural Eastern Oregon, Sunday.

  • A guardrail where a bus overran and plummeted 200 feet down an embankment in rural Eastern Oregon Sunday, <a href="http://www.huffingtonpost.ca/2013/01/01/oregon-bus-crash_n_2392360.html">killing nine and sending multiple to hospitals</a>.

  • Emergency personnel respond to the scene of a multiple fatality accident where a <a href="http://www.huffingtonpost.ca/2013/01/01/oregon-bus-crash_n_2392360.html">tour bus careened through a guardrail</a> along an icy Oregon highway and several hundred feet down a steep embankment.

  • Emergency personnel respond to the scene of a multiple-fatality accident where a <a href="http://www.huffingtonpost.ca/2013/01/01/oregon-bus-crash_n_2392360.html">tour bus careened through a guardrail</a> along an icy highway and several hundred feet down a steep embankment.

  • Emergency crews respond to the scene of a tour bus crash along an icy Oregon highway that killed nine people and injured more than 20 others.

  • Emergency crews respond to the scene of a tour bus crash along an icy Oregon highway that killed nine people and injured more than 20 others.

  • Emergency crews respond to the scene of a tour bus crash along an icy Oregon highway that killed nine people and injured more than 20 others.

  • Emergency crews respond to the scene of a tour bus crash along an icy Oregon highway that killed nine people and injured more than 20 others.

  • Emergency crews respond to the scene of a tour bus crash along an icy Oregon highway that killed nine people and injured more than 20 others.

  • A tour bus careened through a guardrail along an icy Oregon highway and several hundred feet down a steep embankment Sunday, killing nine people and injuring more than 20 others, authorities said.

  • Emergency crews respond to the scene of a tour bus crash along an icy Oregon highway that killed nine people and injured more than 20 others.