Updated

Ronene Ando was startled awake around 1 in the morning by the sound of her 3-year-old pit bull's high-pitched bark.

She begged Ruby to go back to sleep, but the dog was "persistent." Sitting at the bottom of the stairs, Ruby continued to whine until Ando finally rolled out of bed.

As a certified therapy dog through Paws for Love, a program run by a local SPCA in Buffalo, New York, Ruby has been trained to be calm and quiet. When Ruby continued to bark, despite Ando's commands to stop, the owner knew something wasn't right.

"We live on a remote, dead-end street," Ando told Fox News. "It's not like we have traffic. The neighbor's dogs weren't out. If she wants to go out she rings a bell; she doesn't bark."

Somehow Ando managed to coax the panting dog back upstairs and made her lay down. But within minutes, Ruby was back on her paws and running down the stairs.

Ruby dpg 3

Ronene Ando says her pit bull, Ruby, is a certified therapy dog. (Ronene Ando)

"It went on for about an hour and a half I'll bet," Ando said. "I know that this dog breed is pretty smart. They don't bark for nothing."

Ando followed the sound of Ruby's barks. The dog had broken through the gate placed at the bottom of the stairs and was sitting outside the door to Ando's garage.

"I opened the garage door and could smell something," Ando described. "It smelled like propane."

Sure enough, Ando saw a propane heater in the corner of her garage leaking gas. If she had waited too much longer, Ando says she and her boyfriend could have suffered from carbon monoxide poisoning.

Ruby 2

If it weren't for Ruby, Ronene Ando says she could have suffered from carbon monoxide poisoning. (Ronene Ando)

"There is no doubt in my mind this girl -- after barking for hours in the middle of the night -- may have saved our lives," Ando said.

Ando says she placed the propane heater in her garage and cracked the door to vent the area to prevent her pipes from freezing.

"I'll never do that again," Ando said. "But thanks to Ruby, everyone's okay. [Pit bulls are] very protective of their owners."