Foreign Policy Research Institute A Nation Must Think Before it Acts Planning a Sea-borne Terrorist Attack

Planning a Sea-borne Terrorist Attack

The following is a hypothetical scenario drawn from open-source information. It is intended only as an illustration of the use of technology against highly technological societies, and the security impacts that need to be addressed in decision-making about the use and logistics of such technologies.

Increasing demand for energy is intensifying the pressure to import large volumes of natural gas to the United States. Using wellhead liquefaction technology, natural gas may be delivered to consumers relatively cheaply. One typical project to build a port facility for this gas is the Philadelphia Gas Works’ proposal at the Tioga Terminal on the Delaware River. Even assuming, as the company does, that state and federal governments will provide ongoing physical security for the terminal, the failure to include a security impact analysis in the project proposal is a critical failure, and is emblematic of similar failures with respect to security in almost every project proposal and decision since September 11, 2001.


In the late 1970s, in the wake of the 1973 OPEC embargo and the subsequent “oil shock,” energy economics made it feasible to use existing technologies to capture, compress, ship, and market the wellhead natural gas that had, prior to that time, simply been flared in oil fields in the Middle East, South Asia, and elsewhere. By using some of the captured gas as the source of power for the cryogenic plants, the gas could be condensed, and the cleaner, more energy-dense fractions shipped in giant, specially designed tankers to the cold-weather markets in North America and Europe.

According to US government sources, “Large LNG tankers hold up to approximately 130,000 cubic meters of LNG in liquid form, or about 2.8 billion cubic feet. As of late 2003, there were 151 LNG tankers worldwide.”[1] Distributors have constructed, “four marine receiving terminals located at Elba Island, GA; Cove Point, MD; Everett, MA; and Lake Charles, LA. Higher U.S. natural gas prices in recent years have stimulated plans for expansion and new construction of LNG marine terminal facilities. According to the Federal Energy Regulatory Commission, in addition to expansion plans at the four existing LNG import facilities, in the Lower 48 States, more than 35 proposals have been put forth to serve North American markets.”[2] Among these is included Philadelphia, PA.[3]

In order to assess the risks associated with LNG shipping and port operations, in 1978, Peter van der Linde determined that under certain circumstances (scenarios) the consequences of a single accidental rupture of an LNG tanker would cause the scale of devastation usually associated with a nuclear attack (without the nuclear fallout.)[4] Following van der Linde’s analysis, the consequences of these accidental scenarios have been imagined for New York City, Boston, and other ports where LNG storage and distribution facilities have been planned or are now operating.

Prior to the attacks on the USS Cole in October 2000, and on the French taker Limburg in October 2002, the public’s perception of the implications of direct terrorist attacks on shipping was limited to the Palestinian hijacking of the Achille Lauro in October 1985, in which 400 passengers were held hostage, and one, a wheelchair-bound American, was killed and thrown overboard. Military-style destruction of vessels by small-craft loaded with explosives was not considered to be a credible threat to shipping.

The attack on the Cole by al Qaeda operatives in the harbor in Aden, Yemen changed all that. Using a small inflatable boat loaded with explosives the attackers were able to blow a 40×60 foot hole in the side of the armored ship, inflicting heavy damage both above and largely below the waterline. Seventeen Navy personnel were killed and thirty-six injured in the attack. Shortly thereafter, a small boat laden with explosives attacked the French tanker Limburg at Ash Shihr, Yemen. In that attack, both the inner and outer hulls of the double-hulled ship were penetrated, and damage extended, according to the Captain, “Seven or eight meters into the cargo hold which was filled with crude oil.”

Similar to oil tankers, LNG tankers are double-hulled. Unlike oil tankers, however, LNG cargo is contained in a series of three to five giant “thermos bottles” — spherical or prismatic tanks — that maintain the cargo at -260°F at normal atmospheric pressure. Under current standards, LNG tankers are not armored, nor are they designed to withstand deliberate attack. Instead, the tanks are surrounded by insulating foam that is, in some cases flammable, and in all cases, fragile. They are, in fact, constructed to meet the international “Gas Tanker Code” and must also meet the US Coast Guard “Type IIG” standard of subdivision, damage stability, and cargo tank location, neither of which is designed to minimize, no less prevent, the consequences of an intentional terrorist attack on an LNG tanker.

In addition to safety standards, the energy industry often notes that the US Coast Guard maintains an “exclusion zone” around LNG tankers during port operations under the terms of regulation 33 C.F.R. 127. As with many regulations, however, monitoring and compliance requires only that the owner/operators of LNG tankers and port facilities maintain responsibility for security training and operations, and that a current security certification by the owner/operator be submitted to the Coast Guard. No active surveillance of the exclusion zone is required, either above or below the water surface, and no protective devices capable of detecting and/or repelling the approach of an explosive-laden small craft is provided. The FY 2006 Federal Budget sent to Congress by the President has also eliminated the Department of Homeland Security’s Port Security Grant Program, despite the US Coast Guard’s own estimate that our ports should spend over $5.4 billion in the next ten years for security improvements.[5]

In addition, although the typical LNG tanker may travel at speeds above 20 kts. on the high seas, in port operations, they are required to maintain much lower speeds, and often rely on tugs to maneuver. As contrasted with small outboard motor-driven boats that can easily achieve speeds over 40 kts. and can turn within their own lengths, LNG tankers are the sea-going versions of the proverbial “sitting ducks.”


Assuming that a group of terrorists has the tactical objective of a coordinated attack on an LNG tanker or port facility (and, for purposes of this discussion, ignoring any coordination with other groups with the objective of causing massive disruptive attacks on the entire energy infrastructure and markets), the initial phase of the operation would be the acquisition of a suitable small vessel. This is trivial since, in recent years, inflatable (and rigid inflatable) boats equipped with relatively powerful outboard motors have become available for purchase through any number of mail-order catalogs. Keep in mind that these boats can achieve speeds of over 50 mph and easily carry loads of hundreds of pounds in addition to the driver. For terrorists finding themselves short of case, in many harbors these boats are often moored or docked in relatively unattended areas, and with little or no means to prevent theft. Furthermore, because such craft are typically used only on weekends, a missing small boat is unlikely to be noticed for quite some time.

For those planning the attack, the next step is the acquisition of appropriate explosive materials. And again, obtaining the materials and know-how is not very difficult. For example, for the attack on the Murah Building in Oklahoma City, a devastating bomb was easily concocted from readily available materials: common fuel oil and ammonium nitrate fertilizer, which may be purchased at any farm supplier in large quantities. Other explosives (and detonators) are similarly easy to obtain, particularly for today’s well-funded and geographically dispersed terrorist organizations. As far as know-how is concerned, a simple search of the Internet will result ample public domain technical information, as well as descriptions of the “tradecraft” that is needed to purchase and transport the needed materials. And, where appropriate information is proscribed or unavailable on the Internet, manuals and training information has been assembled and widely distributed by al Qaeda.

Finally, in order to complete the planning for an attack on an LNG tanker, it would be necessary for the terrorist group to obtain precise information about the design, current location and itinerary of a target LNG tanker. This information must be sufficiently precise to permit the group to attack by direct interception at high speed, to avoid detection and timely reaction by the Coast Guard or local marine law enforcement agencies. And again, modern information technologies have made the task relatively simple. Without any consideration for its potential misuse, the Internet provides an ideal tool: the Vessel Tracking Information System (VTIS.)

Developed roughly five years ago, the VTIS is a real-time traffic information network used by captains and pilots in many of the world’s busy shipping ports. Telemetry systems, relying on existing global positioning system receivers and communications radios, instantly transmit position, course and related information. Sophisticated systems carried by port pilots even provide a visual display of all large ships in the harbor, and compute future tracks to reduce the chance of a collision.

Many ports around the world have or are now installing VTIS, and many of these are interconnecting them using the Internet. One source, “,” currently provides free, real-time information on each vessel transiting many of the world’s busiest harbors, along with detailed information about each ship including a photograph, size, position, speed, heading, and destination. For a nominal fee, the system even offers the ability to watch for particular ships transiting user-defined zones, and then instantly sending this information to the subscriber via an email address, which may be a cellphone, or similar device. Note that, while the ports of Philadelphia, Wilmington, and Trenton/Camden, are not yet connected to the system, implementation is likely in the near future.

Clearly, with real-time information on the position, heading, speed, and destination of an LNG tanker, together similar information for most of the other vessels in the port, execution of a Cole-style attack would be a relatively simple exercise. Even if the terrorists were not intent on a suicide mission, the additional investment of a few hundred dollars would permit the purchase an automatic pilot system that could be controlled by radio or cellular telephone from the shore.

Consequences of an Attack

Despite van der Linde’s and other warnings, and the examples of several cases of earlier accidental releases that have resulted in the detonation of LNG, the consequences of a rupture of an LNG tanker and subsequent ignition of the gas were not thoroughly studied by United States government security agencies until 2004. In the 2004 study by Sandia National Laboratories, the resulting report (quietly released on 21-Dec-2004), estimated that an intentional attack on an LNG tanker would result in a vapor cloud of explosive gas spread over a radius of almost 2 miles from the ship. Any source of ignition within that vapor cloud would instantly cause an explosion of devastating proportion and horrific effect.

The US military’s largest non-nuclear weapon is the so-called “daisy cutter” bomb, (designated BLU-96), disperses 2,000 lbs. of a flammable hydrocarbon, has a blast zone of over 500 feet in radius, and consumes all available oxygen within that zone, and for some distance beyond. Compare this with the 130,000 cubic meters of LNG contained in a typical tanker: 3,237,472.7 MMKJ (million kilo joules) of energy, or the equivalent of 775 kilotons of TNT. (N.B. The bomb that destroyed Hiroshima yielded 15 kilotons of TNT equivalent.[6]) Keep in mind that the conflagration zone envisioned by Sandia for an LNG tanker attack extends outward for as much as three miles from the ship. In this zone, everything is exposed to searing temperatures, and all of the oxygen is consumed by the explosion, thus suffocating all living things. Beyond this zone, massive damage results from the shock wave. For cities that have large buildings with glass facades, for example, nearly universal destruction of the glass in the zone beyond three miles creates a killing field both inside and outside the structures, as glass, propelled by the shock wave propagating outward at over 775 mph from the explosion zone, is rained on citizens from above.

Making Rational Choices for Philadelphia and Elsewhere

In the calculus of terrorism, the odds are always with the terrorists. As so many witnesses pointed out to the 9-11 Commission, while those who protect us must be right all of the time, terrorists need only succeed once. Furthermore, no society can afford to protect every potential target, against all kinds of threats, all of the time. But we can — and must — begin to make choices that take into account the range of potential threats and the “security impacts” (effectiveness) of the available alternative means of providing security, and we should analyze the costs and benefits (efficiency) of each of these methods. We should then choose the alternative that presents, for similar benefits, the least security risk.

As an example of the need for regulations to require this form of security impact analysis, consider the proposal to locate an LNG terminal at the Tioga Marine Terminal in Philadelphia’s Port Richmond neighborhood. (Roughly the same analysis pertains to any other proposed site, regardless of location.) The Tioga location, less than a mile from a major interstate bridge, and approximately two miles from Independence Hall, is also heavily populated. In addition, since tanks would have to be erected to permit the offloading of tankers and storage and distribution of the LNG, there are additional risks from accidental or intentional destruction of the shore-side facilities.

In addition, each full tanker would be required to transit the river, through three other major interstate bridges that would have to be shut down for brief periods as the tankers pass underneath, and within only a few hundred yards of historic sites, oil refineries, chemical plants, hotels, and recreational facilities. Although the proposal is still in its early stages, to date, no security impact analysis of the proposed shipping operations or port facilities has been commissioned. Even more significantly, questions of safety and security have been largely omitted from the current review process. As matters now stand, it appears that those proposing the new LNG terminal simply assume that the states and local governments will bear the entire responsibility and costs for such a study, and for liabilities associated with operation of the facility.

One alternative being proposed for eight locations around the United States (but not yet for Philadelphia) is known as an “offshore” terminal facility. In such systems, ships moor to large anchored structures many miles away from populated areas, offloading their LNG cargo through a pipeline buried underneath the channel. In some instances, water is used to warm the LNG in the pipeline, causing the liquid to become standard natural gas, so that it may be simply fed into conventional natural gas pipelines on-shore, thus not only reducing, but relocating the risk from the LNG tanker operations to safer locations.

According to Coast Guard Captain David Scott, “If you can reduce the public safety impacts of something, all things being equal, then an offshore terminal would be preferable in many respects.”[7] Philadelphia, with the large expanse of Delaware Bay to the South, through which all ships must transit, is in an ideal location to benefit from an offshore LNG terminal. The lower reaches of the Bay are wide and relatively shallow, yet protected from the open sea. Both the New Jersey and Delaware coastlines of the Bay are sparsely populated, and an offshore facility reduces the impacts on delicate coastal wetlands that line the Bay. Van der Linde proposed this solution in 1978, but his suggestion has not yet been seriously considered.


There are clearly many appropriate locations that should be considered for LNG terminal facilities that are proximate to the urban and industrial areas that require diversified energy sources. We recommend that, in addition to the conventional considerations of business viability, regional economic growth, job creation, inter-state competition for resources, and the like, the type of security impact analysis described above be required as an integral part of any decisions related to future LNG project proposals. If nothing else, the current heightened threat from terrorist actions within the US, and the potentially devastating costs in both lives and financial damage make the application of such procedures not only rational, but also sane.







[4] Van der Linde, Peter and Naomi A. Hintze, Time Bomb: LNG, The Truth About Our Newest And Most Dangerous Energy Source, Doubleday, Garden City, NY 1978.


[6] It is highly unlikely either that all of the cargo of an LNG tanker would spill at once, or that it would efficiently ignite, releasing all of its energy at once. However, if one tank of the five on board were to spill and ignite, the energy release would still equal more than 10 Hiroshima bombs.