Fourth in a series about Costa Mesa's political battle.

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He could have spent his retirement traveling the country with his wife or volunteering at a museum, but Tom Arnold decided his 30 years as a firefighter weren't enough.

Arnold had retired after climbing the ranks of the Newport Beach Fire Department. He was settling into a life of leisure and community service.

Then, after rising from relative obscurity, he brokered a truce between the Costa Mesa firefighters and the City Council — two groups who had bickered publicly for years. There was talk of the city outsourcing services to the Orange County Fire Authority, a move municipal firefighters didn't oppose because of the Fire Authority's more-generous retirement plan and other factors.

But the council wanted to keep fire services in-house and signaled a willingness to play ball with the union, sources familiar with negotiations said.

As the city's interim fire chief, Arnold crunched data about emergency response times and convinced both sides his plan could reduce personnel costs while maintaining public safety. In return, firefighters were assured they won't be laid off, and the council can now point to the deal as a rare instance of compromise.

"When the fiscal crisis hit, I said, 'Oh my gosh, I better start paying attention to what's going on in my community,'" said Arnold, a 35-year Costa Mesa resident.

He became a fixture at council meetings, and met with city CEO Tom Hatch and firefighters months before his eventual appointment as interim chief.

Once he joined the department, city administrators bought Arnold specialized software to analyze emergency response times. His data shaped negotiations and helped him gain trust from both sides, labor leaders and council members say.

For much of the negotiations, the two camps were hung up on one issue: minimum staffing. The firefighters' contract required 29 crew members per each of the three shifts, for a total of 87 workers. From the council's point of view, it was a matter of control.

Should a contract dictate how the brass can deploy firefighters, or should the chief and the city CEO have the authority to restructure as they see fit?

Going into the negotiations, the city was in a costly position: The contract required this amount of firefighters, while the department was short-staffed because of early retirements and a hiring freeze. Overtime filled the gap at a cost of more than $3 million in the 2010-2011 fiscal year.

Today, the department is down nine firefighters.

"It was pretty clear we had to change how we were doing business, as the economy was changing and the [firefighting] business was changing," Arnold said.

High overtime costs drew criticism from both sides of Costa Mesa's debate: Labor critics claimed firefighters were milking the system, and supporters said the city's excessive employee cuts forced wasteful spending and endangered the community.

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Overtime costs

Reining in overtime costs was one of the reasons the council hired Arnold in October 2011.

About the same time, it brought on labor negotiator Richard Kreisler from the Los Angeles law firm Liebert Cassidy Whitmore. Before then, a city staff member and the chief executive or city manager represented the city.