The company that provides school bus transportation for Charleston County schools has filed a federal lawsuit against the Teamsters union over the firing of a bus driver caught on camera using a cellphone while driving a bus.

Durham School Services LP filed the suit Friday against Teamsters Local 509 of West Columbia, which represents the company's Charleston County drivers and driver aides.

The suit stems from a dispute between Durham and the union over the firing of a bus driver last year. According to the suit, a school bus camera captured driver Marquette Cooper Alston using a cellphone while operating a school bus.

Under a five-year collective bargaining agreement, both Durham and the union have agreed that "text messaging or use of personal items such as cellphones while operating a passenger transport vehicle" is grounds for termination, the suit said. After learning of the incident, Durham fired Alston on Sept. 24, 2013.

Following the bus driver's termination, the union filed a grievance on behalf of Alston with a regional grievance committee asserting that she had been "terminated without just cause." The committee, which functions as a joint labor management panel, includes union representatives as well as representatives from various companies like Coca-Cola and UPS.

According to the suit, the committee during a meeting in January wrongly overturned Alston's termination based on a technicality. They said Durham did not provide a copy of Alston's termination letter to the committee and that therefore Alston had not been fired.

Durham, in the suit, asserted that the committee ignored the company's offer to provide a copy of the letter and that no members of the committee asked to see the letter. Instead the committee voted to side with the union and overturn Alston's termination without reviewing the letter, the suit said.

L.D. Fletcher, president of Local 509, on Monday said he was unaware of the suit but that he was familiar with the circumstances of Alston's termination. Fletcher said the union had been in the process of filing its own suit against Durham for not complying with the grievance committee's decision and putting Alston back to work. Alston has not driven a bus since her termination in September, Fletcher said.

Fletcher said according to the collective bargaining agreement and grievance committee bylaws, any decisions of the committee are "final and binding." The union has been working with Charleston County schools to "make Durham" put Alston back to work but that so far that hasn't happened, Fletcher said.

Fletcher claimed that there were no students on the bus on the day Alston was caught using her cellphone and that she was not texting. According to Fletcher, Alston was the driver of a bus for special needs students and was calling parents to let them know she was running late due to mechanical issues. Alston could not be reached for comment Monday.

Carina Noble, vice president of communications and marketing for National Express Corporation, Durham's parent company, said the company does not comment on pending litigation. Noble did not comment on Fletcher's assertion that Alston was calling parents but said the company "has a policy that prohibits the use of mobile devices by drivers while the bus is being operated."

This is not the first time Local 509 and Durham have butted heads. In January, Durham filed an unrelated federal suit that stems from a dispute over whether Durham violated the collective bargaining agreement by using nonunion employees and contractors to fix bus seats and clean vehicles. According to court documents, that suit could go to trial in November if efforts to resolve the dispute in mediation fail.

Durham also transports students for Beaufort County and Dorchester District 2. Both suits pertain only to Charleston County, where a labor contract between the union and Durham runs through Aug. 15, 2017. In each suit, the Warrenville, Ill.-based company is asking the court to rule on the labor grievances raised by the union and other unspecified relief.