A Knoxville family is devastated after a fire engulfed their home and killed 37 of their 40 cats early Tuesday.

The Knoxville Fire Department extinguished the flames shortly after midnight. Fire crews assisted three cats with oxygen in the front yard of the house fire on the 4600 block of Ball Camp Pike.

The cats crews saved "seem to be doing fine," according to KFD Captain D.J. Corcoran. Firefighters were unable to save the remaining 37 cats.

"Flames started shooting out of the hallways so fast," said Connie Brock, who has lived in the home with her husband Tim for more than a decade.

Brock said she was asleep when the flames erupted through the house.

"(My husband) said, 'Come on, let's go,' and I said, 'What about the cats?' He said, 'Come on, let's go, we'll try to get them,'" Brock said.

The Brocks said they have been rescuing cats over the last year-and-a-half. The couple started with seven cats, but says the animals mated with a male that wasn't neutered and quickly multiplied.

Connie Brock said they did get the cats vaccinated and dewormed, and were in the process of finding them good homes when the fire hit.

With no renter's insurance and most of their belongings destroyed, they are now forced to start over.

Courtney Kliman, a spokesperson with Young Williams Animal Center, urges pet owners to neuter their cats eary to avoid overpopulation.

"One female cat can have three litters a year, and each litter can have six to eight kittens. So if you do the math, that can add up to thousands and thousands of cats within a couple of years," Kliman said

The animal center also offers several other resources for pet owners, including free or low-cost vaccines as well as a food pantry.

Corcoran said the department's first priority is human life, but every engine is equipped with oxygen masks that could be used for either humans or pets.

"I don't know that the outcome could have been any different when you've got that many animals," Corcoran said.

For now, the family is grateful for their lives, and thanking the department-- and one firefighter in particular.

"She really helped us with all the cats and getting them together," Tim Brocks said of one firefighter who helped. "She was an excellent firefighter."

"When that woman helped those kittens, I was so thankful for her because she made sure they were going to live," Connie Brock said.

Corcoran said the fire appears to have started in the rear bedroom, but the exact cause is unknown.

Authorities contacted the American Red Cross to provide assistance to the family.