The main component of natural gas is methane, it itself is a non-toxic flammable gases. Like all other fuels, natural gas burning need a lot of oxygen. When users using the stove or water heater not pay attention to ventilation, indoor oxygen will reduce a lot, caused by the incomplete combustion of natural gas. The consequences of incomplete combustion is to produce poisonous carbon monoxide may eventually lead to poisoning of the user or due to lack of oxygen suffocation.

The density of natural gas (methane) at 0 C, 101.325kPa is 0.7174kg/Nm3; the relative density of natural gas (the density of air  S air=1) is 0.5548.
Visible, natural gas than air weigh half as much, if there is room in the leakage of natural gas, inevitable agglutination in the upper part of the room to want to exclude it, should be in the upper part of the room open hole leading to the outside, an increase in air natural convection.

Natural gas is flammable, explosive gas, colorless, tasteless, non-toxic. Adding a bromine agent into natural gas is in order to facilitate the detection of natural gas leakage, which using colorless and odorless gas to add flavor of the liquid medicine. Along with liquid medicine agent gasification, gas agent with special taste to ensure that the gas leak can be human or instrument immediately perceptible.
At present, we use the addition of bromine agent is four hydrogen thiaphenol, which quantity according to the regulations of the relevant specification,and will not be harm to the human body.