The processed natural gas is very inflammable; however it is odourless and essentially colourless. Therefore to detect the presence of natural gas for leakage is required for preventing a fire or explosion. To do that, small amounts of a mercaptan( t-butyl mercaptan) that has strong unpleasant smell is added as an odorant to the natural gas. These odorants are considered to be non-toxic in the very low concentrations. The odorizing of natural gas started in the US after 1937 New London School explosion had killed over 300 students and faculties.  The presence of natural gas in the coal mines is detected by using the methane sensors as any coal-bed methane does not have any odour.  The mining equipment is also specifically developed for avoiding the ignition sources.

Every year, there are few incidents of explosions caused by natural gas leaks. The affected structure includes small businesses, individual homes, boats and others. It happens when an internal leak accumulates the gas inside the structure. The blast is enough to cause significant damage to the building. These cases of explosion may lead to minor to moderate injuries to the people. In very rare occasions, the natural gas gets build up in high enough quantities for resulting in a deadly explosion. This large scale explosion may leads to disintegration of few buildings in the process. The gas is lighter and tends to dissipates readily in the outdoor surroundings. However, it may get accumulated in dangerous quantities if suitable weather conditions prevail.

There are tens of millions of structures around the world that uses fuel and that makes the individual risk of using natural gas significantly less. The natural gas heating systems are basically a minor source of carbon monoxide deaths in the US.  In fact, the improvements in natural gas furnace designs led to reduction of CO poisoning accidents. The presence of advanced detectors warn of unsafe levels of explosive gases.