Short answers, pulled from the story.
Carbon monoxide is a colorless, odorless, and tasteless gas that kills without a sound, scent, or visible sign. It is the most common cause of fatal air poisoning in many nations because it is undetectable by human senses.
Carbon monoxide poisoning is the most common type of fatal air poisoning and can lead to long-term neurological effects such as cognitive and behavioral changes. Acute exposure causes death, while chronic exposure to low concentrations may cause lethargy, headaches, and flu-like symptoms.
Joseph Priestley first synthesized carbon monoxide in 1772, and Carl Wilhelm Scheele isolated it from charcoal in 1773. William Cruickshank identified it as a compound containing carbon and oxygen in 1800.
Indoors, carbon monoxide is emitted from malfunctioning fuel-burning stoves, blocked flues, and tobacco smoke. In the mining industry, the gas is known as whitedamp and is generated by internal combustion engines, explosives, and the low-temperature oxidation of coal.
Carbon monoxide acts as a gasotransmitter that regulates blood pressure, reduces inflammation, and promotes the growth of new blood vessels. It is produced naturally by the catabolic action of heme oxygenase on heme derived from hemoproteins such as hemoglobin.