According to police, the girl was left inside her family's car on Monday morning.
"It appears it was a very busy morning for the family. They have several other children as well and in an effort to get everybody where they needed to go, the toddler was left in the backseat," said officer Steve Hegarty.
Temperatures reached above 90 degrees Fahrenheit in Tampa that day.
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Police say the girl's parents called 911 around 6:30 p.m. after finding their child in their Jeep.
Officers said the toddler was not breathing. The 1-year-old was transported to the hospital where she was pronounced dead.
Police say the death appears accidental and officers have found no signs of foul play.
"The dad used the vehicle the toddler was in to take people to school and to work, then took a separate car to work and that caused him to forget the child was in the backseat of the car. He left and went to work and then came home," said Hegarty.
The case remains under investigation.
Last year was the worst in history for child hot-car deaths in the United States, with a total of 54 fatalities nationwide, according to data collected by KidsAndCars.org, a national nonprofit child safety organization. Now at 50 deaths, this year is getting extremely close to matching that record.
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Janette Fennell, president of KidsAndCars.org, wants parents to understand that accidentally leaving your child in the car "can happen to anyone."
"As a county we need to understand that you can't educate a brain not to forget," she told ABC News Tuesday, explaining that the "No. 1 indicator of a hot-car incident is a change in routine."
KidsAndCars.org is advocating for Congress to pass the Hot Cars Act of 2019, which would require rear occupant alarm technology in all cars so the presence of a child can be detected.
"There's two automakers already that have that type of technology in their vehicle -- it's not like it's a mystery," Fennell said.
"No child should endure the tragedy of dying while trapped in a hot vehicle," Rep. Tim Ryan, D-Ohio, said this summer after the bill was introduced. "The unfortunate reality is that even good, loving and attentive parents can get distracted."