Carbon monoxide is a colorless, odorless, and tasteless gas that is highly toxic and responsible for 40 deaths in Ireland in 2010. Symptoms of carbon monoxide poisoning include headaches, sickness, dizziness, and general lethargy. Sources of carbon monoxide include gas appliances, blocked or cracked chimneys, portable heaters, cars in garages, and barbeques in enclosed spaces. To prevent carbon monoxide poisoning, people should fit carbon monoxide alarms, regularly service appliances, and ensure good ventilation. If carbon monoxide is detected, turn off fuel burning appliances, open windows, leave the property, and contact emergency services.