CO exposure typically has three levels of severity. The initial symptoms of CO poisoning can look a lot like the flu. The signs include flu-like symptoms such as headache, tiredness, dizziness, confusion and nausea. But these symptoms are just the minor ones. Exposure to high concentrations of CO can cause unconsciousness, convulsions, cardiac or respiratory failure, and even death.
These poisoning symptoms may not appear right away. Unless there is an extremely high concentration of CO in the air, symptoms of CO poisoning make take time to surface. It is important to be aware of the progression of these symptoms and to be alert to any physical changes that victims might exhibit. If you suspect CO poisoning, evacuate the building and make sure victims get fresh air and seek immediate medical attention. If the building uses natural gas, notify National Grid as soon as possible through your dispatcher.
Please see Module 3, Poisoning symptoms