LNG Has a Proven Safety Record
The LNG industry’s highest priority has always been safety and security, which is reflected in the industry’s enviable safety record. LNG is not stored under pressure and it is not explosive. Although a large amount of energy is stored in LNG, it cannot be released rapidly enough if released into the open environment to cause the overpressures associated with an explosion. LNG vapors (methane) mixed with air are not explosive in an unconfined environment. A major incident resulting in a large release of LNG could result in a fire, but only if there is the right concentration of LNG vapor in the air (5% – 15%) and a source of ignition.
The LNG industry provides appropriate security, planning, prevention and risk mitigation in close coordination with local, state, and federal authorities, including the U.S. Coast Guard. These measures significantly reduce risks from intentional events such as terrorist acts.
More than 135,000 LNG carrier voyages have taken place without major accidents or safety or security problems, either in port or at sea. (The International Group of Liquefied Natural Gas Importers (GIIGNL) – 2011).
LNG ships are double-hulled, with more than six feet of void space or water ballast between the outer and inner hulls and the cargo tanks. The double hulls help to prevent leakage or rupture in the event of an accident. LNG ships are also equipped with sophisticated leak detection technology, emergency shutdown systems, advanced radar and positioning systems, and numerous other technologies designed to ensure the safe and secure transport of LNG.
The U.S. Coast Guard determines the suitability of every LNG ship that delivers cargoes into and out of the U.S. through a rigorous annual inspection. If a ship fails the inspection, all deficiencies must be fixed before it can unload its cargo or leave the country. LNG ships are issued a Certificate of Compliance by the Coast Guard to state that they are in complete compliance with U.S. regulations.
Studies undertaken by various technical authorities and Sandia National Laboratories on LNG shipping safety and security confirm that risks from accidental LNG spills, including as a result of collisions and groundings, are highly unlikely due to the rigorous safety policies and practices put in place by the LNG industry. Risks resulting from intentional events, such as terrorist acts, can be greatly reduced with appropriate security, planning, mitigation, and prevention. The industry has these precautions in place.
The LNG industry carefully follows requirements set forth by the International Maritime Organization, Federal Energy Regulatory Commission, Department of Transportation, and the U.S. Coast Guard and works closely with the Department of Homeland Security to ensure that its operations are safe and secure.
LNG ships are fast for their size and less prone to pirate attacks since they sit high in the water relative to crude oil carriers and conventional cargo ships. The industry takes piracy seriously and follows international best practices. There are additional security measures, procedures, and equipment on board LNG tankers to deter and repel such attacks, but they are not disclosed in order to increase their effectiveness.
Before a ship enters a U.S. port, the captain is required to inspect each and every compartment and report this inspection as part of the 96-hour notice. This written inspection is given to the U.S. Coast Guard upon arrival in U.S. waters. The Coast Guard may then perform its own inspection. There are other security procedures in place when the vessel is at sea, which are also not disclosed to ensure their effectiveness.
Every crew member must either have a visa that has been approved by the U.S. State Department, or the ship has to have an armed guard to prevent crew members without visas from disembarking. The crew list is provided to the U.S. Coast Guard 96 hours prior to arrival. A background check is run on all crew members by the Coast Guard and U.S. Immigration and Security Authorities.
LNG import and export terminals are designed with multiple layers of protection and must meet rigorous safety regulations. They are equipped with spill containment systems, fire protection systems, multiple gas, flame, smoke and low- and high-temperature detectors and alarms, automatic and manual shut-down systems, video surveillance systems, and highly trained personnel.
The U.S. Coast Guard determines the suitability of a waterway to transport LNG safely and creates safety and security rules for each specific port. The Coast Guard works with terminal and ship operators and host port authorities to ensure that policies and procedures conform to required standards and works with operators to conduct emergency response drills. The U.S. Coast Guard has the authority to require and receive background checks of crews, conduct ship searches and may require the use of Sea Marshals, who are specially trained and armed U.S. Coast Guard personnel.
Liquefaction Facility Safety
Liquefaction of natural gas to LNG requires cooling the natural gas until it becomes a liquid. These processes include gas conditioning before liquefaction, processing and managing the impurities and liquid hydrocarbons, and storage and handling of the refrigerants that are used to cool the natural gas to a liquid state.
The refrigerants used in the LNG process typically consist of some combination of the following light hydrocarbons: methane, ethane, ethylene, propane, butane and isopentane. Nitrogen is also a common refrigerant component.
Refrigerants used in natural gas liquefaction plants are safely produced and handled routinely in hundreds of refineries, petrochemical plants and natural gas processing facilities across the United States and world.
Methane, ethane, propane and butane are normal components of natural gas. Natural gas and its components are also widely and safely used as commercial products by industries, businesses, farms and residences. For example, propane is commonly used in home cooking grills and for heating purposes.
Natural gas liquefaction facilities must comply with rigorous government regulations and industry codes and standards for its engineering, operations, maintenance and personnel training.
The liquefaction process requires significant compression systems for refrigeration that include large centrifugal compressors typically driven by gas turbines, steam turbines or large electric motors. This type of rotating equipment is larger than typically found in LNG import terminals and is similar to what is found in refineries, power plants and large chemical plants. Rigorous measures are utilized at liquefaction facilities to ensure the safe design and operation of this equipment.