Groton — The city and the firefighters’ union have agreed to a two-year contract that increases the minimum number of firefighters on each shift from three to four.

The union had long sought the change for safety reasons, said Daniel Tompkins, president of the Groton Firefighters, IAFF Local 1964.

Five people normally work each 24-hour shift. If two people were off, the three firefighters on duty had to wait for help from other departments to fight a fire since safety rules require that if two people go into a burning structure, two others must be outside, Tompkins said. They could enter immediately, however, if an occupant was trapped inside.

“When we have to wait for help from other departments to get there, sometimes that can be a significant wait,” Tompkins said. “This will allow us to attack the fire quickly. It’s safer for us and ultimately for the residents.”

City Mayor Marian Galbraith said the City Council supported the staffing change, it was just a matter of finding a way to pay for it.

“We worked together to find a way,” she said.

The city added $70,000 to the budget for overtime since paying overtime would be less expensive than hiring, Galbraith said. The union agreed to change the way time off is taken to control overtime, which Galbraith said was crucial to changing the staffing.

Previously two firefighters could take the same day off. Now, Tompkins said, when one firefighter has requested a specific day off, another firefighter can take that day too but each firefighter is only allowed to be the second person off six times a year to limit the number of opportunities for overtime.

The union also agreed to use the same insurance plan city employees use. The city wants all of its employees to eventually be on one plan since it’s easier to administer and less costly with more people, Galbraith said.

Wages will stay the same under the contract in the first year and increase 1.5 percent in the second year. The City Council unanimously approved the deal Monday. The union, which represents 15 firefighters and fire captains, unanimously approved it last month.

Both Galbraith and Tompkins said they were pleased with the outcome and the fact that the negotiations went smoothly.

“We kept focused on the issues and we didn’t do any banging on the table,” Galbraith said.

“When both sides have a common goal, it’s easy to reach that goal if you’re willing to work together,” added Tompkins.

j.mcdermott@theday.com