Federal transportation officials Thursday shut down a bus company involved in a fatal crash on the Pennsylvania Turnpike after finding the two drivers involved never took required drug tests and falsified records.

Mr. Ho Charter Service of Bethlehem was shut down for drug- and alcohol-testing violations and failing to ensure its drivers complied with work-hour rules, the Department of Transportation said.

The bus rear-ended a tractor-trailer Monday in western Pennsylvania, killing 39-year-old co-driver Bo Hua Tan of New York City and injuring two dozen Asian tourists.

A man who answered the company phone Thursday and identified himself as Edward Ho said that one bus in New York would be driven back and parked. He otherwise did not comment on the shut-down order.

The department had been investigating the company even before the crash. A June 7 compliance review found the company failed to conduct random drug and alcohol tests on its drivers, leading the agency to issue substantial civil penalty fines. The company had an automatic 45-day period to appeal.

"Mr. Ho Charter Service continued to disregard federal regulations. The company hired two new drivers — the two drivers involved in the June 27 fatal crash — without requiring federally mandated pre-employment controlled substances tests on either driver," the agency said in a press release.

After the crash, investigators found the same two drivers had falsified their records, the agency said.

The cause of the crash remains under investigation. It wasn't immediately clear whether the surviving driver was tested for drugs after the crash or whether a toxicology report was available on the dead driver.

The company's actions "demonstrate a continuing disregard for compliance with (federal safety regulations) and a management philosophy indifferent to motor coach safety," the agency said.

The National Transportation Safety Board is also investigating. The agency does not investigate all fatalities but tends to focus on those that could shed light on safety problems or trends, spokesman Terry Williams said.

Twenty-five people have died in six such U.S. bus crashes this year, the head of the Motor Carrier Safety Administration recently told Congress.

Fifteen people were killed in March when a bus rolled on its side and struck a pole in New York, shearing the top off much of the vehicle.

Last month, four people died when a bus crashed after the driver dozed off at the wheel in Virginia, and a 6-year-old boy died in a crash in Kentucky.


Associated Press writers Matt Moore in Philadelphia and Joan Lowy in Washington contributed to this report.