Carbon monoxide (CO) is a colorless, odorless, and tasteless gas, making it dangerous because it cannot be detected by human senses. This toxic gas is a byproduct of combustion, meaning any fuel-burning engine, including those in cars, generates it. A car can cause carbon monoxide poisoning. Exposure to high concentrations of this gas can rapidly lead to illness, permanent organ damage, or death.
How Vehicle Engines Generate Carbon Monoxide
Automobile engines produce power by igniting carbon-based fuels like gasoline in the presence of oxygen (combustion). Ideally, this process results only in carbon dioxide and water vapor. Carbon monoxide forms when there is insufficient oxygen for the fuel to burn fully, leading to an incomplete combustion reaction. The engine then releases this toxic compound through the exhaust system.
Modern vehicles mitigate this danger with a catalytic converter integrated into the exhaust system. This converter uses precious metals like platinum, palladium, and rhodium to facilitate a chemical reaction. It oxidizes CO into the less dangerous carbon dioxide (\(\text{CO}_2\)) before the exhaust exits the tailpipe. However, if the engine is poorly tuned or the catalytic converter is damaged or removed, the concentration of CO can increase exponentially.
High-Risk Scenarios for CO Exposure
Several situations allow carbon monoxide from a vehicle to accumulate to dangerous levels, posing a threat to occupants and bystanders. One common and hazardous scenario is idling a car in a closed or attached garage, even for a short time. The CO gas quickly builds up in the enclosed space and can seep into living areas of an attached home. This accumulation happens even if the garage door is partially open.
A primary risk while driving is a compromised exhaust system (e.g., holes, cracks, or loose connections). A damaged exhaust pipe can leak unfiltered, high-concentration CO directly underneath the car, where it can be drawn into the passenger cabin through air vents or structural openings. Driving with the trunk or tailgate open can create a vacuum effect, pulling exhaust fumes back into the vehicle’s interior. A tailpipe blocked by snow, mud, or other debris can force the exhaust back into the engine compartment, venting the gas directly into the vehicle cabin. Prolonged idling in congested areas, like traffic tunnels with poor ventilation, can also expose occupants to dangerous concentrations of exhaust from surrounding vehicles.
Recognizing the Signs of CO Poisoning
Carbon monoxide is toxic because it interferes directly with the body’s ability to transport oxygen. When inhaled, CO molecules preferentially bind to the hemoglobin in red blood cells, forming carboxyhemoglobin. Because CO binds to hemoglobin over 200 times more readily than oxygen, it quickly displaces the life-sustaining gas, starving the brain and heart of oxygen.
Early symptoms are often subtle and can be mistaken for common ailments, such as the flu or food poisoning. Mild exposure presents as a dull headache, dizziness, nausea, and weakness. As exposure continues and the concentration of carboxyhemoglobin rises, symptoms progress to include confusion, impaired vision, chest pain, and vomiting.
Severe poisoning leads to neurological effects, including loss of muscle control, seizure, and loss of consciousness. Because the gas is undetectable, a person may become confused and unable to recognize the danger or take action. Death can occur rapidly in minutes or hours, depending on the concentration of CO in the air.
Emergency Response and Prevention Strategies
The immediate response to suspected carbon monoxide poisoning must prioritize getting to fresh air and seeking medical help. If you or someone else experiences symptoms, immediately exit the vehicle or enclosed space and move to an area with clean air. Call emergency services and inform them that you suspect carbon monoxide exposure. Do not attempt to return to the area until it has been confirmed safe by professionals.
Preventative measures focus on vehicle maintenance and safe operating practices. Have your car’s exhaust system, including the muffler and catalytic converter, inspected regularly for leaks or damage. Never idle a vehicle in a closed space like a garage, even if the door is open. When starting a car in winter, ensure the tailpipe is clear of snow or ice blockage.
For homes with attached garages, installing a carbon monoxide detector is a safety measure. These detectors should be placed near sleeping areas and within the garage. Never sleep in a running vehicle, and be cautious when operating a vehicle with a remote starter to ensure it is not left idling in an unventilated area.