For new cars, convenience comes with carbon monoxide risk

There's an urgent, renewed push to make push-start cars safer as more people nationwide are poisoned by carbon monoxide gas when vehicles are accidentally left running in garages.

At least 28 people have been killed since 2006, 15 of them in Florida.

Earlier this month, four senators, including U.S. Sen. Bill Nelson, urged federal regulators to force automakers to program some sort of warning.

Timothy Maddock lives his life by these to-do lists, not by choice but out of necessity.

Read: CO can be deadly if not handled correctly

"Here's how crazy it is: I wrote 'Three o' clock attorney right here and here,'" he said.

Maddock suffered a severe brain injury that cost him his short-term memory after he and his girlfriend were poisoned by carbon monoxide gas eight years ago.

By the time Palm Beach County deputies discovered them in a third-floor bedroom, his girlfriend, Chasity Glisson, was dead and Maddock was unconscious.

"I remember when I fell down right at the bathroom door," Maddock said. "I saw the dog throwing up under the bed the same way she was."

Investigators said Glisson brought her key fob into the Boca Raton house not realizing the car in the garage hadn't turned off.

Federal regulators don't require automakers to program an automatic shutoff or warning when this happens.

Channel 9 borrowed a keyless car and parked it in a garage to find out how quickly carbon monoxide can become deadly.

A Seminole County firefighter placed a carbon monoxide monitor in the garage before closing the door.

Carbon monoxide meters soared to more than 100 parts per million within 25 minutes.

"Sustained exposure to these levels, could mean nausea, vomiting, headaches, blurred vision," said Lt. Michael Scott, of the Seminole County Fire Department.

At that rate, levels could reach 1,200 parts per million within three hours, Scott said.

"That's deadly -- like, instantaneously deadly," he said. "Yes, IDLH is what we call it -- immediately dangerous to life and health."

Without the proper ventilation, that buildup of carbon monoxide would start seeping into a home, Scott said.

Maddock said he is furious that no one has held automakers accountable.

"I don't get it. They do it for seat belts. They do it for airbags," he said. "How many more people are going to die before they do something about it?"

The speed at which carbon monoxide builds up in a garage depends on how well insulated it is and the car.

The National Highway Traffic Safety Administration in 2010 said programming an alert would cost automakers pennies per vehicle.

Cox Media Group