CLIFTON PARK — An appeals court has ruled that Shenendehowa Central School District violated a union contract when it fired a school bus driver who had marijuana in her system.

The state Supreme Court Appellate Division, Third Judicial Department, ruled Thursday that Shenendehowa didn’t have grounds to fire Cynthia DiDomenicantonio without considering other options after her urine tested positive for marijuana use in a random drug test in October 2009.

DiDomenicantonio submitted to the test upon returning to the bus garage after delivering children to school that day. When the test results came back, she was placed on unpaid suspension and then fired in November 2009. She had worked as a bus driver for almost 10 years.

In its Thursday decision, the court sided with an arbitrator who recommended that DiDomenicantonio be reinstated to her position without back pay. The district had previously refused to comply with that finding from arbitrator James Gross and took Civil Service Employees Association Local 1000 to court in August 2010.

In November 2010, state Supreme Court in Saratoga County sided with the district, with Judge Thomas D. Nolan Jr. writing in his decision that the district can get rid of anyone who puts students at risk. CSEA then appealed to the Appellate Division.

Whether DiDomenicantonio had consumed marijuana wasn’t the point of contention — although she contended she hadn’t smoked but may have been exposed to secondhand smoke or inadvertently eaten marijuana-laced food, the arbitrator ruled she was under the influence of the drug because she tested positive for it. The issue, according to the Appellate Division’s decision, was that the district’s union contract didn’t mandate she be fired, as the district said it did.

Lawyers for the district argued the district had a “no tolerance” policy for drug use, but the arbitrator and the appeals court found no such policy. Instead, the union contract and drug policy listed several disciplinary options for positive drug tests, including fines, suspension and termination, as well as further drug and alcohol testing if the employee returns to work.

The court states in the order: “If [the district] intended to implement a zero tolerance policy, it could and should have negotiated with CSEA to include such mandatory language in the [collective bargaining agreement].” Since it didn’t, the district has to follow what’s in the contract, the judges said.

It is unclear whether DiDomenicantonio still wants the job back more than two years after being fired, but the decision goes beyond her specific case and bodes well for worker issues, said CSEA spokeswoman Therese Assalian.

“There is a clear process for discipline,” Assalian said. “They chose to throw that out the window and proceed a different way. You can’t just throw that out the window because you don’t like it.”

Shenendehowa spokeswoman Kelly DeFeciani said Thursday the district hasn’t determined what it will do next.

“At this point, we’re in discussions with our lawyer to determine what the decision does mean and what our options are going forward.”

CSEA attorneys also are reviewing the decision, Assalian said.