The tragic discovery was made inside of a vehicle in the Smithtown parking lot around 4:15 p.m. Monday.
Police said the toddler was left in the car for approximately eight hours after a 54-year-old woman forgot to drop her granddaughter at day care.
The woman went to work and left the child in a car seat in the back seat.
Approximately eight hours later, the woman went to pick the child up at the day care when she realized she left the child in the car.
The child was transported to Saint Catherine of Siena Medical Center in Smithtown where she was pronounced dead.
Cathy Chase, president of Advocates for Highway and Auto Safety, said their statistics show that on average 40 children die each year after being left in a hot car.
"When you hear about these incidents, especially in the summer months, it's gut-wrenching," Chase said. "Cars can be like a greenhouse effect for children, when the sun is shining through it just heats up very quickly."
Some newer model cars have backseat detection technology and Chase said they are advocating to make it available to everyone.
And even if your car doesn't have the technology, experts say the tragedies are still preventable if you are proactive.
"Never leave your child in a hot car even for a minute, when you put your child in the backseat, put something in the backseat with them -- phone, purse wallet something you'll need when you get to your destination," Chase said.
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