Update: A fire that killed three dogs at a Knoxville animal clinic was an accident.

According to Captain DJ Corcoran with the Knoxville Fire Department, the investigation shows the fire started in a laundry area of Fannon Animal Hospital, most likely in elictrical equipment.

Original story: March 4, 2017

The Knoxville fire department said three dogs were killed by a fire at Fannon Animal Hospital on Clinton Highway Saturday morning.

Firefighters responded to the scene just after 6:00 a.m., where they found heavy smoke billowing from the hospital.

"The first priority was the fire itself and then when they realized what the building was, an animal hospital, they thought there might be some animals inside so they started looking," Captain DJ Corcoran with the Knoxville Fire Department said. 

Firefighters found the dogs and immediately tried to revive them. They used specific respiratory masks designed for dogs but were unsuccessful. The masks were donated to the fire department by a local pet store a few years ago. 

Corcoran said any loss, whether it's a pet or human, can be difficult on crews.

"Our firefighters realize that's somebody's pet, that's somebody's companion," he said.

The business was not open and no people were inside when the fire started. The three dogs were staying at the hospital overnight Friday and were the only animals in the building. 

Knoxville Fire Department is still investigating the cause of the fire.