CAUSE OF DEATH: suffocation, poisoning
REQUIRED EQUIPMENT: breathing apparatus
Do you smell something funny? Methane might be best-known for the fact that a lot of it comes from cow burps and sewage, but in higher concentrations, it’s no laughing matter.
Not only is methane a potent greenhouse gas, but it’s also poisonous, causing suffocation, vomiting, and other flu-like symptoms. Farm workers on Earth have been killed by large amounts of methane escaping tanks used to store livestock excrement.
Astronauts trying to visit the gas giant exoplanet HD 189733b would be advised to bring plenty of oxygen, as the abundance of methane and other poisonous gasses, like carbon monoxide, in its atmosphere would otherwise cause a quick death due to suffocation.