BRENTWOOD, Calif. (KRON) – Four dogs are dead following an overnight fire late Thursday night into early Friday morning at a kennel in Brentwood. Fire investigators believe the blaze was accidental.

East Contra Costa Fire Protection District investigators believe an electrical malfunction in an air conditioning unit caused a fire inside Derty Dog Canine Retreat & Fitness in Brentwood just before 10 p.m. Thursday night. Fire fighters kept the flames from spreading beyond the one building on fire.

A fire that investigators believe started in an air conditioning unit spread to the building, killing four dogs. Another 15 dogs at the kennel were accounted for and appeared to be in good condition.

The fire was contained quickly without endangering any surrounding buildings.

“We have not had issues in the past with this facility. We haven’t had too many calls out there,” said Fire Marshal Steve Aubert.

Aubert says firefighters regularly train performing CPR on cats and dogs, adding that any loss of life is tragic.

“Whether its a civilian loss of life, or even a family pet. All of those are important in all of our lives, and they mean a lot to everybody,” Aubert said.

This case is currently under investigation by East Contra Costa Fire Protection District, which urges anyone with any questions or additional information to call them at (925) 634- 3400.

Bay City News contributed to this report.