Why is a leaky exhaust system considered dangerous?

A leaky exhaust system is considered dangerous primarily because it can result in carbon monoxide poisoning. Carbon monoxide is a colorless, odorless gas that can be extremely hazardous, as it can accumulate inside a vehicle's cabin when there is a leak in the exhaust system. This buildup poses a serious health risk to the occupants, as inhaling carbon monoxide can lead to symptoms such as headaches, dizziness, confusion, and even life-threatening conditions at high levels of exposure.

While a leaky exhaust system can indeed reduce gas mileage and cause loud noises—potentially distracting the driver or signaling a maintenance issue—these factors are not as critical in terms of immediate health threats. Additionally, a leaky exhaust does not contribute to vehicle theft directly; this option does not relate to the primary concerns regarding safety and health. Therefore, the correct understanding highlights the dangers of carbon monoxide exposure as the key reason why addressing a leaky exhaust is essential for the safety of vehicle occupants.