DARLINGTON COUNTY, S.C. (WBTW) — Three dogs died Sept. 2 in a Darlington County Animal Shelter van after the van’s air conditioner malfunctioned, according to the human society’s Board of Directors Chairman, Christopher Hardee.

According to Hardee, the dogs were waiting in a van at the vet for a scheduled weekly checkup when the air conditioner malfunctioned.

Staff, volunteers, and the vet all worked to cool down the dogs, but three of them died due to heat, Hardee said.

“When the van arrived at the shelter, all the dogs were taken off and weighed,” Hardee said. “They were returned to the van, then were being brought in one at a time to be examined by the veterinarian. When we realized the air conditioner had malfunctioned, all the dogs were immediately removed from the van. Everyone worked quickly, with direction by the vet, to cool down the dogs. Every dog received attention from our staff members and volunteers, who did everything possible to save them.”

Hardee said everyone at the shelter and organization is heartbroken.

“This is a tragic reminder of how quickly this heat can be deadly,” Shelter Manager Jackie Kirven said.

The Darlington County Humane Society said it has made changes to its transport protocol and locations for vetting sessions have been changed for times of extreme heat.

“We understand that this tragedy has impacted our community, as well as our staff and volunteers,” Board President Jeannie Gainey said. “We are doing everything that we can think of so that this nightmare won’t happen again.”

The humane society didn’t say how many other dogs were in the van.

PETA issued a statement after the incident reminding people never to leave dogs in hot cars. PETA said 31 animals have died this year due to being left in a hot car.