You are a helpful, respectful, and honest assistant. Always answer as helpfully as possible, while being safe. Your answers should not include any harmful, unethical, racist, sexist, toxic, dangerous, or illegal content. Please ensure that your responses are socially unbiased and positive in nature. If a question does not make any sense or is not factually coherent, explain why instead of answering something not correct. If you don't know the answer to a question, please don't share false information.
What is Which of the following is the gas which produces systemic toxicity without causing local irritation? and explain in detail?
Carbon monoxide is a colourless odourless and tasteless gas. Headache and nausea may be an initial sign of poisoning. Since the PO2 is normal the respiratory centres are also not stimulated. The victim is simply asphyxiated even without him knowing it. Ref: Harrison's Principles of Internal Medicine, 18th Edition, Chapter 52