At least eight dogs being transported to a K-9 training facility in Indiana died after a driver’s AC unit failed,Devin Grosvenor causing the dogs to go into “heat related medical distress,” authorities said Friday.

The driver, whose name was not immediately released, was taking 18 shepherds from Chicago O’Hare International Airport to Michigan City, Indiana, on Thursday, The Associated Press reported, when the driver was caught in a two-hour traffic delay, the Lake Station Police Department said in a statement on Facebook.

“The AC unit that was being used to keep the canines cool failed,” police said in the statement.

The dogs went into “heat related medical distress” because of the extreme heat, police said. After hearing some of the dogs barking, the driver pulled over at a convenience store and gas station in Lake Station, Indiana, where the driver found several dogs dead and others suffering, AP reported. 

Police said the scene was ‘chaotic’ and took an ‘emotional toll’ on everyone involved

When police and Lake Station Fire & Rescue/EMS arrived, store employees and witnesses were attempting to save the dogs.

“There was an overwhelming response from both agencies so much so that civilians and so many others stopped to help where they could,” police said. “The scene was chaotic and took an emotional toll on all that were involved in trying to save as many canines as possible.”

Jennifer Webber, executive director of the Humane Society of Hobart, responded to the call at 7:40 p.m. local time and said the dogs were salivating heavily, wobbling, vomiting and convulsing, which are signs of a heatstroke, AP reported. 

“There were already several dogs dead on the scene, and multiple failing fast,” Webber told AP. “Their crates inside the truck were completely trashed on the inside and the little water bowls were the size you’d give a parrot. And they were empty and torn up as if the dogs were exasperated.”

Police said it was not ‘an act of animal cruelty' 

After speaking with the driver, police said it was not “an act of animal cruelty or neglect but a mechanical failure of the AC unit that was being used in the cargo area,” police said.

Webber, who said she is authorized to conduct an investigation, told the AP she encountered resistance when attempting to gather facts.

“He shouldn’t have been traveling at all. So No. 1: That is neglectful,” Webber said.

Contributing: The Associated Press