Carbon monoxide (CO) is a highly toxic, colorless, and odorless gas that is produced through the incomplete burning of fuels such as propane, coal, wood, oil, kerosene, natural gas, and gasoline. In fact, one of the most common sources (opens PDF in new window) of CO exposure is the internal combustion engine — a primary component of gasoline-fueled automobiles.
The typical internal combustion engine used in most cars and trucks can produce high concentrations of CO. While changes in engine design, fuel, and emission control devices have reduced CO emissions, faulty or poorly maintained exhaust systems can result in increases in CO within the cabin of the car or truck.
Other technological advances such as the introduction of keyless ignition vehicles (opens in new window) have added to the ongoing risk. Without the required act of turning the key off and removing it from the ignition switch, some owners of keyless ignition vehicles inadvertently leave the engine running, flooding their environment, typically their garage, with deadly levels of CO.
The lethal consequences of CO in engine exhaust is tragically illustrated by the hundreds of people who die each year from carbon monoxide poisoning caused by a running vehicle inside a closed garage.
Others die or become ill in homes with attached garages, while stranded in their car, or while driving or riding in a vehicle with a defective exhaust system.
Automobiles and Carbon Monoxide — The Basics
Gas-powered automobile engines can produce high concentration of carbon monoxide (CO) quickly, overcoming exposed individuals before they realize they are at risk.
To put this in perspective, the Centers for Disease Control (CDC) notes that CO concentrations reach the Immediately Dangerous to Life and Health (IDLH) concentration of 1,200 parts per million (ppm) in only 7 minutes when a small 5 horsepower gasoline engine is run in a 10,000 cubic foot room.
Persons affected by CO display a lack of reasoning caused by reduced oxygen to the brain that can impair function and make them less likely to discern the danger in the environment.
The Causes of Carbon Monoxide Exposure from Automobiles
While many risks of carbon monoxide (CO) exposure stem from mechanical issues, there are a series of best practices regarding limiting CO exposure that should be considered when operating a motor vehicle.
In general, you should avoid:
- Operating a vehicle with a defective exhaust system.
- Operating a vehicle with a defective emission system or poorly tuned engine.
- Driving a vehicle with the trunk lid or rear tailgate open.
- Driving a vehicle with holes in the car body.
- Warming up a vehicle in a garage, even with the outside garage door open.
- Operating vehicles in a garage, carwash, or any enclosed building.
Risks Specific to Defective Exhaust Systems
Even a properly tuned gasoline engine will produce more than 30,000 parts per million (ppm) of carbon monoxide in the exhaust stream before the catalytic converter. Engines that are poorly maintained or defective can result in exhaust leaks.
- An exhaust leak can allow escape of carbon monoxide before it is converted to non-toxic CO2 in the catalytic converter.
- The carbon monoxide leaking from the exhaust system can enter the vehicle through holes in the body or open windows or doors.
NOTE: The catalytic converter is ineffective when there is insufficient oxygen in the area, which can occur in closed spaces like garages. Therefore, it is dangerous to leave your car running in a garage, even if the garage is open.
If you are experiencing issues with carbon monoxide stemming from an automobile, you should immediately call a mechanic or service technician. If you suspect an issue, have your car towed to the service garage to avoid exposure.
Your service technician can inspect your vehicle to diagnose and correct any problems due to faulty parts, improper maintenance, or other issues.
To learn more about the effects of CO poisoning, please review Understanding the Effects of Carbon Monoxide.