CHICAGO (CBS) — A Wisconsin limousine company has been ordered to shut down immediately, after a recent fatal accident in Illinois.

The U.S. Department of Transportation’s Federal Motor Carrier Safety Administration has ordered Edgerton-based Lyons Limousine to halt all service both in and out of Wisconsin, after finding it poses “an imminent hazard to public safety.”

Aaron Nash, 20, was driving a limousine for Lyons on March 25, when he crashed on the Jane Addams Tollway (Interstate 90) around 7:30 a.m., and the limo rolled onto its roof. A 53-year-old Wisconsin woman was killed in the crash, and six other people were injured. The limo was on its way from Wisconsin to O’Hare International Airport at the time.

Federal rules require interstate commercial drivers to be at least 21 years old.

The FMCSA said Nash had a poor driving record, as did the company’s co-owner, Mary Lyons. Nash had his Wisconsin driver’s license suspended in September for failing to pay a fine. He also has previous convictions on five previous occasions between April 2012 and June 2015, including violations for speeding, obstructing traffic, following too closely, disobeying a traffic sign or signal, and failure to wear a safety belt.

A federal investigation found Lyons has violated multiple safety regulations – including repeatedly using an underaged driver, failing to conduct necessary background checks on drivers, not keeping proper maintenance records, and failing to monitor its drivers’ time on the road to prevent fatigued driving.

“Lyons Limousine’s use of unqualified and underaged drivers with poor driving records, lack of inspection, repair, and maintenance records, and complete disregard of the hours-of-service regulations substantially increases the likelihood of death or serious harm to drivers, passengers, and the motoring public if not discontinued immediately,” the FMCSA said in a news release.

Attorney Tim Cavanagh has filed a lawsuit on behalf two men who were injured in the crash, including one who has severe spinal injuries.

“It’s very disturbing. This 20-year-old driver should not even have been driving this limousine. He didn’t have a CDL, a commercial driver’s license. He wasn’t of age to be driving this limousine,” he said.

Cavanagh said he wants all evidence from the crash preserved so his experts can examine it.

The investigation also found Lyons did not maintain the required levels of public liability insurance, and didn’t have safety and operating authority registration.

If Lyons violates the order to shut down, the company’s owners could face a fine of up to $25,000, up to a year in jail, and thousands more dollars in civil penalties for any other safety violations that might be found.