Carbon monoxide ($\text{CO}$) is a colorless, odorless, and highly toxic gas that is often generated by the incomplete combustion of carbon-containing fuels. Due to its small molecular size, it has an affinity for hemoglobin in the blood that is approximately 200–250 times greater than that of oxygen. When inhaled, $\text{CO}$ rapidly binds to hemoglobin to form carboxyhemoglobin ($\text{COHb}$), which significantly reduces the blood's oxygen-carrying capacity. This chemical impediment to oxygen transport can lead to tissue hypoxia, potentially causing symptoms ranging from headaches and dizziness to severe neurological damage and death depending on the level and duration of exposure. Sources of dangerous $\text{CO}$ include malfunctioning furnaces, vehicle exhaust, and certain types of burning waste.