DALLAS, Texas (CNN) -- Federal authorities have ordered a company tied to a Texas bus crash on Friday that killed 17 people to cease operation, saying it poses an "imminent hazard."
The damaged bus is hauled from the crash scene on a flatbed truck Friday in Sherman, Texas.
The orders -- issued by the Federal Motor Carrier Safety Administration -- apply to motor coach operations Angel Tours Inc. and Iguana Busmex Inc., and their chief, Angel De La Torre.
Authorities say De La Torre continues to run his unsafe fleet of buses under a new name, Iguana, after they ordered Angel Tours to cease operation in June.
"Angel Tours and Iguana currently operate vehicles in a mechanically unsafe operating condition which, if operated, would pose an imminent hazard to the public," the orders state.
CNN tried to reach Angel Tours, but its voicemail was full on Sunday and not accepting messages. An e-mail to De La Torre was not immediately answered.
The action follows Friday's bus crash, in which the driver of the bus apparently lost control on northbound U.S. 75 in northeast Texas, smashing into a guardrail before rolling on its side and sliding into a gully. The accident happened near the Texas-Oklahoma state line. Watch as the fire chief describes the crash scene »
Twelve people were declared dead at the scene, and five others died at hospitals, officials said. Police estimated that, in addition to the deaths, 33 to 39 of the 54 passengers and lone driver suffered mild to serious injuries. iReport.com: Were you there? Send photos, video
On Friday, NTSB member Debbie Hersman told reporters that the bus' right front tire had been retreaded, in violation of safety rules. The blown tire was discovered near the crash site. It was the only one of the tires that was recapped, and the only one whose tread separated, she said. Asked what caused the Goodyear tire to lose its air, she said, "We don't know the answer to that question; that's why we're here." Watch what investigators are learning about the accident »
The orders say that federal authorities served De La Torre with a similar order to cease operations on June 23 after Angel Tours received an "unsatisfactory" safety rating during a compliance review. The Motor Carrier Safety Administration denied his request for an upgraded safety rating after Angel Tours failed to provide evidence it had improved the safety conditions of its fleet.
For its part, Iguana "constitutes a mere continuity of Angel Tours' operations," the documents say. De La Torre registered Iguana on June 27 -- just four days after Angel Tours was ordered to shut down.
According to the documents, the companies committed 17 safety violations, including:
-- Using regrooved, recapped or retreaded tires on the front steering axle of buses;
-- Operating buses that were not periodically inspected;
-- Using drivers before the company received results from pre-employment drug tests;
-- Failing to investigate the driving records and backgrounds of drivers.
Before the companies can be considered for returning to operation, they would have to explain the reason for noncompliance and develop a detailed plan of action for remedying the list of violations.