What are the risks associated with LNG vapor?
When LNG comes in contact with warmer air, it begins to vaporize, returning to its natural gaseous state – natural gas. As LNG vaporizes, the cold vapors will condense the moisture in the air, often causing the formation of a white vapor cloud until the gas warms, dilutes, and disperses.
LNG can be safely handled provided that it is stored in industry standard tanks (double walled, insulated, of proper metals according to the relevant EU (CEN) standards, or to the US standards, e.g. NFPA59A, transferred in closed systems with redundant controls. LNG facilities and equipment are designed with special features to ensure containment of LNG and its vapors. In the unlikely event of any inadvertent leak, there are three main risks:
- LNG and LNG vapor can be very cold and, if not using protective insulated gear, could cause cold burns. In order to prevent exposure to the extreme cold associated with LNG, personnel are required to wear special cryogenic gloves and other personal protective equipment during transfer activities
- An LNG vapor cloud could be hazardous if it collects in a confined space; it would displace the oxygen in the confined space, potentially generating an asphyxiation risk. In the design of facilities that handle LNG, great care is taken to minimize congestion and confined spaces where LNG vapor could accumulate.
- Like any fuel, while in liquid state, LNG will neither burn nor ignite. However, as LNG warms, it vaporizes, and the vapors are flammable. An LNG vapor cloud could potentially ignite if it is exposed to an ignition source, provided that the LNG vapors are sufficiently warmed and within the flammable range. If a spill was to occur at an LNG facility, the chance of the vapor cloud igniting is reduced by minimizing the presence of ignition sources in the vicinity. The same precautions are taken at fueling facilities delivering other fuels like gasoline and diesel.