LEWISTON – Five school bus drivers were pulled from their routes Wednesday after police discovered they were ferrying children to and from local schools without proper license endorsements.

Police began investigating the drivers Tuesday after a former Hudson Bus Lines employee reported that some drivers with the company were not properly trained to operate buses.

Lewiston School Department transportation director Butch Pratt was notified of the claims and checked the qualifications of the men and women who drive for Hudson. What he found was that five who operate the mini-buses were not legally entitled to do so.

“We’re obviously concerned about it,” Pratt said. “We have a contract with them and this is clearly a violation of that contract.”

Hudson provides bus service for Lewiston public schools.

The drivers who were found in violation were ordered by Hudson to stop driving until they had received endorsements on their driver’s licenses allowing them to operate school buses.

By contract, a driver who takes the wheel of a school bus is required to get about 40 hours of training and a minimum of 16 hours of annual instruction, which involves training in matters such as traffic laws and interpersonal skills.

It was not immediately clear how long the improperly licensed employees had been working for Hudson, which employs roughly 45 drivers.

“We’re in the process of investigating this,” Pratt said. “We’re trying to figure out what went wrong and to make sure it doesn’t happen again.”

Hudson operates 27 full-size buses, seven mini-buses and a dozen mini-vans, transporting about 2,700 children each day. Its buses travel an estimated 348,000 miles per year, taking children to and from school and to and from extracurricular activities.

Leon Levesque, superintendent of Lewiston schools, said he was told by an official at Hudson that the problem with the drivers may be due to an interpretation of license requirements, though he stressed Wednesday night that the matter was under internal review.

There were no indications that the Hudson employees were bad drivers, he said. But contracts demand that all bus drivers provided by the company be properly endorsed.

“Our first priority was to make sure we are in full compliance with the law,” Levesque said.

He said Hudson quickly pulled the drivers in question off school routes and replaced them with others with proper endorsements. Levesque said there would be no disruption to school bus routes.

“Over the years, we’ve had a good relationship with Hudson,” Levesque said. “It’s unfortunate that this occurred.

Hudson General Manager Todd McCollough could not be reached for comment Wednesday night.

Based on Bartlett Street, the company was purchased in 2007 by Student Transportation of America, which provides transportation services to more than 200 school districts in the U.S. and Canada.