As summer’s heat arrives, so do the calls to police about children and dogs left in cars, the windows rolled up tight, waiting as adults shop and run errands.

That can lead to tragedy. A Ridgefield toddler died last summer when his father apparently forgot he was in the car seat as he went to work.

To remind parents and pet owners that heat can kill and to double-check the back seat for any potentially vulnerable passengers, Fairfield police have started a new campaign reminding people: “If you love ’em, don’t leave ’em.”

The campaign’s signs will be posted in town parking lots and will be offered, free of charge, to local businesses. Police Chief Gary MacNamara, First Selectman Michael Tetreau and state Rep. Brenda Kupchick, R-132, held a press conference Friday morning to kick off the campaign.

“I think businesses will want this,” Kupchick said. The signs include the Police Department’s number to call if someone sees a child or pet left behind in a hot vehicle.

She said she met with MacNamara and Animal Control Officer Paul Miller about a year ago, following the Ridgefield child’s death.

“We’re looking for Fairfield to be one of the first in the state to do this,” Tetreau said, “and we hope other towns will follow our lead.”

MacNamara said the campaign message may be simple, but that doesn’t mean it isn’t an important one. “Anytime a child or animal is left in a car, it’s already too late,” the chief said.

The town will reach out to local businesses through the Chamber of Commerce and the Business Watch program run through the Police Department.