Is Carbon Monoxide safe when breathed in?

Inhalation of carbon monoxide displaces oxygen in the blood by binding to hemoglobin, forming carboxyhemoglobin, which deprives vital organs like the brain and heart of oxygen, leading to symptoms such as headache, dizziness, nausea, weakness, confusion, shortness of breath, chest pain, loss of muscle control, blurred vision, sleepiness, loss of consciousness, seizures, coma, brain damage, heart damage, and death.

Why here

Carbon monoxide is a gas that is directly inhaled into the lungs, where it rapidly enters the bloodstream and interferes with oxygen transport.

What would have to be true

Acute exposure to high concentrations (e.g., 800 ppm can be fatal within minutes). Chronic exposure to lower levels can also cause adverse effects, with regulatory limits including 50 ppm (OSHA 8-hour TWA), 35 ppm (NIOSH 8-hour TWA), 25 ppm (ACGIH 8-hour TWA), and 9-10 ppm (WHO/EPA/ASHRAE 8-hour).

Inhalation of carbon monoxide during pregnancy poses a special risk to fetuses, potentially leading to miscarriage at high levels and slower than normal mental development at lower levels; infants and children have increased susceptibility to CO toxicity due to their higher metabolic rates.

Why here

Carbon monoxide is inhaled by a pregnant individual or child, affecting the developing fetus or child's oxygen supply.

What would have to be true

Breathing high or low levels of carbon monoxide during pregnancy or as an infant/child.

Exposure to carbon monoxide can lead to delayed neurological and neuropsychological sequelae, including memory loss, personality changes, movement problems, fatigue, confusion, difficulty concentrating, and an increased risk of psychiatric conditions like depression and anxiety, which can appear weeks to months after exposure.

Why here

The inhaled carbon monoxide causes oxygen deprivation to the brain, leading to both immediate and delayed damage to the nervous system.

What would have to be true

Acute or prolonged inhalation exposure to carbon monoxide.

Inhalation of carbon monoxide in indoor air reduces the blood's ability to carry oxygen by forming carboxyhemoglobin, leading to symptoms such as headaches, dizziness, nausea, confusion, impaired vision and coordination, and chest pain, and can be fatal at high concentrations. Long-term exposure can lead to fatigue, reduced work capacity, poor learning ability, difficulty in performing complex tasks, and adverse developmental effects in unborn babies.

Why here

Carbon monoxide is a colorless, odorless, and toxic gas produced by the incomplete combustion of fuels from various indoor sources, including unvented kerosene and gas space heaters, leaking chimneys and furnaces, back-drafting from combustion appliances, gas stoves, generators, automobile exhaust from attached garages, and tobacco smoke. Without proper ventilation, CO can build up indoors to dangerous levels.

What would have to be true

Health effects can occur at various concentrations and durations. The U.S. Environmental Protection Agency (EPA) recommends indoor air levels below 9 parts per million (ppm) averaged over 8 hours or 35 ppm for shorter periods. The World Health Organization (WHO) suggests maximum carbon monoxide levels of 9-10 ppm for no more than 8 hours, 25-35 ppm for no more than 1 hour, and 90-100 ppm for no more than 15 minutes. The Occupational Safety and Health Administration (OSHA) permissible exposure limit (PEL) for workers is 50 ppm as an 8-hour time-weighted average, with employees to be removed from enclosed spaces if concentrations exceed 100 ppm. The National Institute for Occupational Safety and Health (NIOSH) recommends an exposure limit of 35 ppm as an 8-hour TWA and 200 ppm as a ceiling. The American Conference of Governmental Industrial Hygienists (ACGIH) has assigned a threshold limit value (TLV) of 25 ppm as an 8-hour TWA. Symptoms like severe headache, dizziness, nausea, and impaired judgment can develop within 2-3 hours at 100-200 ppm. Concentrations of 200-400 ppm can become potentially life-threatening after several hours, and 800+ ppm can be fatal within minutes.