ATTLEBORO, Mass. (WPRI) — Leaving a pet inside a vehicle during the summer – even with the windows open – can be hazardous to the pet, and now if you do so within Attleboro city limits, it will cost you.

At the tail end of a brutal stretch of heat and humidity, Mayor Paul Heroux issued a “zero tolerance” policy for leaving dogs and other pets in hot cars.

Under the new policy, first-time offenders will be fined $150, a second offense will result in a $300 fine and any violations after that will cost you $500 each.

Last month, Eyewitness News was given a demonstration from police that showed how quickly a vehicle can warm up in the summer heat. It’s part of the reason Heroux didn’t include warnings in his new policy. He said common sense should be warning enough.

“The measure of a society is partly judged based on how well we treat our vulnerable,” Heroux said in a statement to Eyewitness News. “Animals are one of our vulnerable populations that many including myself consider our friends and family. It’s cruel to subject them to conditions that are unpleasant and even life-threatening.”

Heroux said he brought the new policy to city’s police chief after encountering someone who had left their dog in the car outside the public library. There’s still a lot of summer left and he said he doesn’t want to see any more animals fall victim to some of the more potentially serious health effects that can come with leaving them in a hot car.

“I want to raise awareness,” he added. “We need to come together as a community and report to the police or the animal control officer when an animal is in a life-threatening situation.”

As a general rule of thumb, pet owners who are going somewhere that animals aren’t allowed should simply leave their pets at home.