(CNN) -- The driver of a large motor coach that crashed in Oregon late last month, killing nine and injuring 39, had worked 92 hours in the seven days leading up to the crash, far exceeding the 70 hours allowed, according to the U.S. Department of Transportation, which Tuesday ordered the Canadian bus company to cease operations in the United States.
The transportation department said the Vancouver-based company, Mi Joo Tour & Travel Ltd., poses an "imminent hazard to public safety" because of its failure to take basic measures to ensure that its drivers are properly rested.
In a 10-page order, the department outlines a list of accusations against Mi Joo Tour & Travel involving its conduct before and after the crash. The DOT said the company failed to test the driver for drugs and alcohol after the December 30 crash.
It also accused the company of continuing to operate in early 2012, when it ordered the company to discontinue operations because of its failure to pay fines. Those fines also involved the company's failure to conduct drug and alcohol tests.
The deadly accident happened as one of Mi Joo's small fleet of buses was returning to Vancouver, British Columbia, from Las Vegas, police said. The bus skidded on ice on Interstate 84 near Pendleton, Oregon, crashed through a guardrail and tumbled down a steep embankment.
A CNN check of a DOT website, billed as a convenient way for passengers to check on bus company safety records, did not yield any information on the company's history of violations. But in response to a Freedom of Information Act request from CNN, the DOT turned over inspection reports showing the company had been cited for 11 violations in 2010 and eight violations in 2011.
The 2010 violations included one "Acute" violation, which led the Federal Motor Carrier Safety Administration, an agency within the DOT, to place the company on "conditional" status. After a 2011 inspection, the motor carrier administration gave Mi Joo a "satisfactory" rating.
During both reviews, the company was ordered to comply with all rules.
Other records also show Mi Joo's operating authority was revoked in 2008 after the motor carrier agency informed the company that it did not have proof of insurance on file. The license was reinstated after two weeks when the company provided proof that it had the required insurance.
In its order this week, the administration says it has discovered a "deterioration in your safety management controls and widespread safety violations that demonstrate a continuing and flagrant general disregard" of the rules.
"Mi Joo does not monitor its drivers' hours of service to ensure that its drivers do not violate" work-hour restrictions," the order says. DOT investigators said Mi Joo does not require its drivers to maintain driver logs and supporting documentation.
Transportation department officials this week defended its inspections of Mi Joo, saying the FMCSA has a "robust compliance program," conducting almost 1,900 compliance reviews in 2012 and more than 100,000 roadside inspections.
It said its consumer website contains the most recent compliance reviews and that rules for what is included on the site are vetted during a public review process.
"Don't risk your life ... by making an uninformed decision," the department says in one promotion for the site.
In news releases and other material, the SAFER website -- for Safety and Fitness Electronic Records -- is promoted as a way for travelers to determine whether bus companies are safe.