In the midst of a nationwide heat wave, with excessive-heat warnings and advisories in place for more than 20 states, it’s natural for those of us who care about animals to worry about their welfare and the risk of their being locked in cars. In just the last few weeks, several reports of pet casualties have rolled in, including a dog left inside a car in northwestern Colorado while the owner was visiting someone; a golden retriever left inside a car in Green Bay, Wisconsin, with the windows rolled up, for three hours; and a dog in Wilmington, Delaware, trapped in a hot car in a makeshift crate.

We cannot say it enough: it is essential for pet owners to ensure that they do not leave their beloved companion animals alone in cars for even a few minutes, and that they take additional steps to ensure that their pets are as safe as possible in the sweltering heat.

Temperatures inside a car can spike quickly into the 100s even while it’s a pleasant 70 degrees outside. Animals are ill-equipped to handle the heat and humidity because they don’t have sweat glands and cannot release the heat that builds up inside their bodies. According to the Humane Society Veterinary Medical Association, "animals pant to evaporate moisture from their lungs, which takes heat away from their body. If the humidity is too high, they are unable to cool themselves, and their temperature will skyrocket to dangerous levels—very quickly."

Even leaving the air-conditioner on is no guarantee; the owner of the dog found dead in Colorado told police she had left the air conditioner on, but when she returned she found the motor was no longer running.

Unfortunately, not many individuals realize the danger that heat poses to their pets, and we continue to see casualties each year. The obvious solution to this perennial problem is public education about the danger of hot cars, and a deeper awareness of animals’ needs in conditions of extreme heat. Here are a few tips on what you can do if you happen to see a pet left inside a parked car. First, learn about the laws in your own state and locality on leaving dogs in cars, make sure that you have your local animal agency and police department non-emergency telephone numbers so you can call if needed, distribute the Humane Society of the United States’ hot car flyer, and, if your state or town doesn’t have a law that prohibits leaving pets in parked cars, contact your lawmakers and lobby for one.

At the Humane Society of the United States, we have also attacked this problem from a policy angle and several states have acted by passing laws that allow first responders and, in some cases, good Samaritans to enter vehicles to remove animals under certain circumstances. Tennessee made history by passing the first such law in 2015, and since then we’ve worked to convince 31 more states to pass similar laws.

This year, the New York State legislature passed a bill that will be heading to the governor for his signature, and we are working with advocates in South Carolina to pass an ordinance that outlaws leaving dogs in cars on hot days.

No animal deserves to die an agonizing and unnecessary death in extreme heat conditions and from being trapped in a hot car. With greater awareness and greater latitude for Samaritan interventions, we can make this world a safer and better one for our animal companions. If you are a pet owner, see these tips on how to keep your pets safe during the heatwave, by limiting exercise, providing ample shade and water, and watching for signs of heatstroke in your pet, among other steps.