More than a year of arbitration has produced a new contract for Butler’s firefighters, but the city is challenging the legality of part of the ruling.

State arbitrator Michael Zobrak issued the binding decision this month on a contract for the International Association of Firefighters, Local 114, which would retroactively span from January 2012 to the end of this year.

Local 114 represents the 18 firefighters, who have been working under a deal that expired Dec. 31, 2011.

The two sides entered arbitration in February 2013.

Zobrak’s ruling awarded city firefighters a 2 percent raise retroactive for 2012 and for 2013, and a 2.5 percent raise for 2014.

Base salaries for firefighters ranged from $48,764 to $54,792 under the previous deal.

While the terms of the arbitration are binding, the city will challenge an issue not addressed by the arbitrator.

City solicitor Jim Coulter said at the council meeting Tuesday night that the city will challenge the legality of the arbitrator failing to eliminate the requirement that the city keep 18 full-time firefighters.

Coulter said the clause has been in the agreements for years, but is illegal.

“The city is required to bargain the wages, hours, and working conditions of its firefighters,” Coulter said. “The city feels the number of firefighters is managerial prerogative that affects the city’s ability to budget.”

The city asked Zobrak to review the clause, but the arbitrator made no comment on it in his ruling.

“The arbitrator did not address one of the issues we wanted,” said Councilwoman Kathy Kline.

The ruling will be appealed to the Court of Common Pleas. Coulter said the city has 30 days to make the appeal.

While the city will fight one aspect of the ruling, the rest of the arbitration is final.

“It’s binding,” said Mayor Tom Donaldson.