Asphyxiating

Asphyxiating materials are a type of HAZMAT cargo that can cause temporary air deprivation when leaked .

In order to transport gasses in as big an amount as possible, many are transported pressurized. In case of a leak, as the gas is equalized with atmospheric pressure, it will take much greater volume than the tank it was transported in. This can cause dislocation of air around the train, potentially leading to suffocation of people and animals in its vicinity.

While generally hazardous, asphyxiating gasses can also be helpful in rare situations. They can help extinguish fires , by dislocating air from an affected area.