The most important source of human exposure to carbon monoxide is cooking or other fuel-burning appliances that are poorly installed, malfunctioning, or used improperly (including inadequate ventilation). Examples include improperly installed home boilers and the use of barbecues and portable generators indoors or in tents.
Because carbon monoxide reduces the amount of oxygen delivered to the heart or brain, certain groups of people, such as pregnant women and young children, and people with coronary artery disease, angina, asthma, or anemia, are at risk of carbon monoxide poisoning.