Septic tank is common in areas where sewage lines are not available. People use septic tank to dump human waste. Here bacteria decompose the waste. But there are some risks also. Bacteria makes methane gas is the process. This property is used in bio gas plant.
In the case of non bio gas plant septic tank, this methane gas is a problem. Accumulated methane gas may create high pressure inside septic tank which may result fetal explosion also. This is why a pipe line on top of the tank is placed so that the tank may release gas.
I the northern district Bogra a septic tank exploded when the pipe line for releasing gas was disconnected. Kholilur Rahman of sixty five died in the incident and six others were also injured.
So check your septic tank as early as possible, if you have any in your house!