A 20-month-old boy was left unattended inside a car for about 10 minutes Monday on Tucson's south side.
The child did not need to be taken to a hospital, said Battalion Chief Barrett Baker of the Tucson Fire Department.
Paramedics remained at the scene to monitor the boy, whose vital signs were normal, including his temperature, Baker said.
The caregivers, a grandmother and a godparent, said that they arrived at their home near South Sixth Avenue and East Ajo Way, and each one thought the other had taken the child out of the car, said Baker.
When they realized what happened, they rushed to get the boy out of the car and took him inside their air-conditioned home. They then called 911, Baker said.
The boy was only wearing a diaper when paramedics arrived at the home. He was acting appropriately for his age, said Baker.
Tucson police were investigating the incident.
No further information was released.
Tucson fire officials released a safety measure reminding adults not to leave their children in vehicles where temperatures "can skyrocket" in a short period of time.
Monday's high reached 102 degrees at 4:47 p.m. at Tucson International Airport, according to the National Weather Service.