DUXBURY, Mass. -- Dangerous carbon monoxide levels in a Duxbury home sent a couple and five firefighter paramedics to the hospital.

NewsCenter 5's Gail Huff reported Tuesday that police believe the fumes seeped into the house because a car was left running in the garage.

Paramedic Tim Geary was released from the hospital Tuesday morning. He said that officials received a 911 call at about 4 a.m.

"My husband just collapsed on the floor," the caller said.

"Is he breathing?" the dispatcher said.

"Yes," the caller said. "He's 72."

Duxbury firefighters and paramedics rushed to Donald and Judith Goodman's Church Street home.

"We arrived at the home. A woman was able to answer the door for us. It was clear to us that she was very confused," Geary said.

Officials smelled car exhaust in the house and realized that a Mercedes in an attached garage was left running overnight.

"We determined very quickly that there were high levels (of carbon monoxide)," Geary said.

The paramedics put on gas masks to enter the area. The concentration was more than 1,500 parts per million. Fifteen is enough to set off the carbon monoxide alarm.

"We were able to find her husband upstairs in his bedroom. He was unconscious. He was unresponsive, in critical condition," Geary said.

"He was airlifted to Boston because he was unconscious and the high levels of carbon monoxide in the house," Duxbury Fire Department Chief Chris West said.

Donald Goodman was being treated at Massachusetts General Hospital. His wife was treated at a south shore hospital.