An Illinois mom was arrested after her 1-month-old son died from “severe” hyperthermia and dehydration — after the newborn was abandoned in a hot car for an “extended period,” according to authorities.

Andrea Luncsford, 25, was charged with endangering the health and life of a child, after her new baby was found dead Monday evening about 7 p.m., the Peoria Police Department said.

An autopsy revealed that the baby, identified as Grayson Luncsford, had been left in a vehicle for an “extended period,” without food, water, or air conditioning, WCBU reported. 

Peoria County Coroner Jamie Harwood said it was difficult to determine how long exactly little Grayson was left in the pickup truck, however, authorities told KBTX that he was left inside the vehicle for more than four hours.

The daytime high for Sept. 16 was 90 degrees, with a low of 59 degrees, according to Weather.com.

The baby had been taken out of the pickup truck and placed in a yard by his grandfather before cops arrived. Harwood said he had been dead for “quite some time” when he arrived.

“This, too is a preventable death,” Harwood said, according to WBCU.

“When you have an infant or a kid in a car for any amount of time in this heat, the outcome is going to be as it is right now today, which is we have the death of a 1-month-old who has died because they were in a car with no air conditioning, no ventilation, no nutrition, no hydration.”‘

The coroner determined that Grayson died as a result of “gross neglect due to severe hyperthermia and profound dehydration,” The Kansas City Star reported.

Harwood urged parents to remember that an infant’s body cannot handle being left alone in a vehicle for an extended amount of time. 

“We have to remember … not even just an infant, (but) even an adult would suffer hyperthermia and dehydration,” Harwood said, WCBU reported.

“It’s going to happen a lot faster for an infant, unfortunately, because of body surface area and the makeup of their bodies and how fragile they are in their infancy anyway.”