The city of Lawrence and the firefighters union have reached an impasse in pay negotiations, so now the two sides will take their dispute to a federal mediator, it was announced Thursday.

Lawrence firefighters are scheduled to receive a 1 percent pay raise in 2015, but the International Association of Firefighters Local 1596 says Lawrence firefighters are making 8.5 percent less than firefighters in peer cities.

“We are losing ground every year,” said Ryan Hornberger, president of IAFF Local 1596.

City officials disagree with the 8.5 percent figure and say a 1 percent increase in 2015 is enough at this time.

“We believe the 1 percent is fair and appropriate and was the amount in the agreement,” said Assistant City Manager Diane Stoddard.

The current memorandum of understanding between the city and union runs from 2012 to 2015 but has a clause to open negotiations for a wage adjustment for 2015.

Under the agreement, firefighters received a 1 percent in increase in 2012, 1.5 percent in 2013, 1.5 percent this year, and are scheduled to receive a 1 percent increase next year.

When the contract started, Lawrence firefighters were making 5 percent less than firefighters in cities such as Lenexa, Olathe, Overland Park, Shawnee, Kansas City, Kan., and others, Hornberger said.

Now they are trailing by 8.5 percent based on research performed by the city and IAFF, he said.

But Stoddard said it is difficult to compare salaries because each city has a different salary structure. While the maximum pay for different categories of firefighters in Lawrence is lower than the peer cities, Lawrence firefighters hit that maximum earlier in their career, she said.

She said adjusting salary structures is something the city would like to negotiate with the union when talks start on a 2016 pay plan.

But union officials said the city has agreed on the peer pay comparisons when it suits its purposes.

“The city’s decision to refute past practices and pay philosophy sends a message that public safety is no longer a priority for the city of Lawrence,” Hornberger said.

Stoddard disagreed with that assertion. “We believe that public safety is a priority, and we appreciate their services that we all depend on. We have continued to reinvest in employee compensation and in critical safety equipment,” she said.

The results of a meeting with a federal mediator aren’t binding. If the two sides fail to reach an agreement, the issue would next go to the City Commission for a decision. No timetable has been set yet to meet with a mediator.