Max, a German shepherd who pulled his owner out of bed as their home filled with carbon monoxide. (CBS)

NOVATO (KPIX 5) — A Novato man’s dog – obtained from a rescue organization – is being credited with returning the favor by saving his life after he was overcome with carbon monoxide poisoning.

Max, a 90-pound German Shepherd, seemed to know his owner, 80-year-old Jack Farrell was in serious trouble after a wall heater malfunctioned, filling their home with natural gas and carbon monoxide.

Farrell said he was sleeping at the time and Max dragged him out of bed by his arm and down a hallway before Farrell was able to wake up and recover.

“Out here in the kitchen, I finally woke up wondering what the hell was going on because he had hold of my arm,” said Farrell. “I’m bleeding like hell and that’s when I called 911.”

Novato Deputy Fire Chief Adam Brolan said by the time firefighters arrived, the carbon monoxide had reached deadly levels. “We took a reading of the environment and found 75 parts per million. To put that into perspective, we don our breathing gear at 25 parts per million.”

“I’d be dead,” said Farrell. “He saved my life. Carbon monoxide is (bleeping) deadly man.”

“Jack could have died,” said Brolan.

Farrell got Max from German Shepherd Rescue of Northern California about a year ago.

Farrell was hospitalized briefly following the incident.

PG&E determined the natural gas and the carbon monoxide leak were caused by debris and soot clogging a gas-powered wall heater in the home.