Gas and Sewer Gas
Never go to sleep in a room where the gas is burning low. As gas may escape into the room, very big fires burning in sleeping rooms are dangerous, especially in charcoal stoves. In underground sewers and wells dangerous gases are found; if a lighted candle will not burn in such a place it is certain the air will be dangerous for any one entering it.
In rescuing a person from a place filled with gas, take a few deep breaths before entering, carry him quickly out without breathing yourself. Gas will not be found near the floor of a building, so you may be able to crawl out where it would be dangerous to walk.