Order Code RS21997
December 7, 2004
CRS Report for Congress
Received through the CRS Web
Port and Maritime Security: Potential for
Terrorist Nuclear Attack Using Oil Tankers
Jonathan Medalia
Specialist in National Defense
Foreign Affairs, Defense, and Trade Division
Summary
While much attention has been focused on threats to maritime security posed by
cargo container ships, terrorists could also attempt to use oil tankers to stage an attack.
If they were able to place an atomic bomb in a tanker and detonate it in a U.S. port, they
would cause massive destruction and might halt crude oil shipments worldwide for some
time. Detecting a bomb in a tanker would be difficult. Congress may consider various
options to address this threat. This report will be updated as needed.
Introduction
The terrorist attacks of September 11, 2001, heightened interest in port and maritime
security.1 Much of this interest has focused on cargo container ships because of concern
that terrorists could use containers to transport weapons into the United States, yet only
a small fraction of the millions of cargo containers entering the country each year is
inspected. Some observers fear that a container-borne atomic bomb detonated in a U.S.
port could wreak economic as well as physical havoc. Robert Bonner, the head of
Customs and Border Protection (CBP) within the Department of Homeland Security
(DHS), has argued that such an attack would lead to a halt to container traffic worldwide
for some time, bringing the world economy to its knees. Stephen Flynn, a retired Coast
Guard commander and an expert on maritime security at the Council on Foreign
Relations, holds a similar view.2
While container ships accounted for 30.5% of vessel calls to U.S. ports in 2003,
other ships carried crude oil (13.2%), petroleum products (19.3%), bulk cargo (18.1%),
1 For discussions, see CRS Report RL31733, Port and Maritime Security: Background and Issues
for Congress, by John Frittelli; and CRS Report RS21293, Terrorist Nuclear Attacks on
Seaports: Threat and Response, by Jonathan Medalia.
2 U.S. Department of the Treasury. “U.S. Customs Commissioner Robert Bonner, Speech Before
the Center for Strategic and International Studies,” Washington, D.C., January 17, 2002; and
Stephen Flynn, America the Vulnerable: How Our Government Is Failing to Protect Us from
Terrorism (New York: HarperCollins, 2004) p. 83.
Congressional Research Service ˜ The Library of Congress

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and cars and trucks (9.1%).3 These ships merit attention as well because terrorists will
look for the weak link. The 9/11 Commission stressed the importance of a balanced
approach to maritime security.4 To this end, this report focuses on the threat of a terrorist
nuclear attack using oil tanker ships. This threat is of particular interest because the
Middle East is the chief source of anti-U.S. terrorism.
Background
Oil Shipments from the Middle East. Crude oil and other petroleum products
account for almost all export earnings of many Middle Eastern nations.5 In turn, 25.6%
of net U.S. crude oil imports in July 2004 came from the Middle East.6 Crude oil from
the Middle East went to 30 U.S. ports in 2003. Those handling the most oil were Blaine,
WA; El Segundo, Long Beach, Los Angeles, and Richmond, CA; Corpus Christi,
Freeport, Galveston, Houston, Port Arthur, and Texas City, TX; Baton Rouge, Gramercy,
Lake Charles, Morgan City, and New Orleans, LA; Pascagoula, MS; Mobile, AL;
Wilmington, DE; and Paulsboro, NJ.7
Crude oil from the Middle East is typically shipped to the United States in
supertankers — Very Large Crude Carriers (VLCCs) and Ultra Large Crude Carriers
(ULCCs). Their size is measured in deadweight tons (DWT), the weight of the stores,
fuel, and cargo they can carry. One DWT is 2,240 lb. While definitions vary slightly,
VLCCs can carry about 200,000 to 300,000 DWT and ULCCs can carry more than
300,000 DWT. A representative ULCC was 60 meters wide and 350 meters long, and
had a draft (depth below the waterline) of 22 meters. They are the largest ships ever built.
The interior of a tanker is divided into multiple storage tanks.
Both the Coast Guard and the Navy state that they do not have responsibility for, or
authority over, security of foreign-flagged vessels at foreign ports.8 Nor do other
American forces. Security of foreign ports rests with foreign governments.
Staging a Terrorist Nuclear Attack Using Tankers. The simplest type of
atomic bomb, and by far the easiest to fabricate, is a gun-assembly bomb, in which one
mass of uranium highly enriched in the fissile isotope 235 (highly enriched uranium, or
HEU) is shot down a tube into another mass of HEU, forming a critical mass and causing
3 U.S. Department of Transportation, Maritime Administration, Vessel Calls at U.S. Ports, 2003,
p. 4.
4 U.S. National Commission on Terrorist Attacks upon the United States, The 9/11 Commission
Report, Authorized edition (New York: Norton, 2004) p. 391.
5 The figures are 90-95% for Saudi Arabia and 95% for Kuwait (source: U.S. Department of
Energy, Energy Information Administration, Country Analysis Briefs) and roughly 85% for Qatar
(source: U.S. Central Intelligence Agency, The World Factbook).
6 U.S. Department of Energy, Energy Information Administration, “Table 3.7: United States —
Oil Imports (Most Recent 12 Months)” for August 2003-July 2004.
7 U.S. Department of Energy, Energy Information Administration, Petroleum Data Publications,
“Company Level Imports,” The American Petroleum Institute aggregated the port and monthly
data from these tables for CRS.
8 Source: Discussions with Navy and Coast Guard officers, November 2004.

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a nuclear explosion. The Hiroshima bomb was of this type; its designers had such
confidence in the design that it was not tested before use. This bomb had an explosive
yield of 15 kilotons (equivalent to 15,000 tons of TNT). Excluding the bomb’s outer
casing, fins, and fuses, this device was 6 feet long and about 6 inches in diameter, and
weighed about 1,000 pounds.9 Some items loaded onto large cargo ships are of similar
or greater size and weight. It might be possible to make a gun-assembly bomb lighter, or
to obtain a more advanced, lightweight “suitcase bomb.”
To stage a nuclear attack using a tanker, terrorists would need to acquire a nuclear
device10 and smuggle it (or key components) onto the ship. Their ability to accomplish
this latter task would likely depend on their ability to infiltrate, bribe, or otherwise work
around local security; on the reliability of security personnel in oil-exporting countries
such as Saudi Arabia, Kuwait, and Algeria; and on the reliability of the ship’s officers and
crew. Terrorists might seek to place a nuclear device inside one of a tanker’s oil tanks,
which would require sealing and cushioning the bomb and possibly attaching it to the tank
wall; or in a dry space on the ship; or in a blister attached to the ship underwater.
Remotely detonating a bomb inside an oil tank or underwater might be difficult: it might
not be possible to attach wires leading out to dry spaces, or to send an electromagnetic
signal (e.g., a cell phone call) through water or oil to the bomb. Detonating the bomb
with a timer would run the risk of the ship not being at the target at the specified time.
Overcoming these challenges might be within the ability of a terrorist group resourceful
enough to acquire an atomic bomb. Terrorists might also smuggle a bomb onto a ship at
sea, as discussed later.
Potential Targets. Terrorists could be expected to target a port that handled a
large volume of oil and other goods and that had a densely-populated area that tankers
passed on their way through a harbor to an unloading terminal. Various cities worldwide
meet these criteria. If terrorists sought major economic damage while minimizing loss
of life, they might try to target the Louisiana Offshore Oil Port, or LOOP, the only U.S.
deepwater oil port that can handle fully loaded supertankers. LOOP, 18 miles off the
Louisiana coast, currently handles about 10% of U.S. crude oil imports. The Panama
Canal might be another potential economic target.
Detecting an Atomic Bomb in a Tanker. Some technical approaches for
detecting atomic bombs in a tanker would fail, especially for a bomb inside an oil tank.
Gamma rays, essentially high-energy x-rays, can be used to create x-ray-type pictures of
the contents of cargo containers, but a tanker’s sheer mass of oil and steel would prevent
any gamma rays from traveling the width of a tanker. Neutrons may also be used to detect
fissile material; neutrons of the appropriate energy level cause such material to fission,
producing neutrons and gamma rays that can be detected. The hydrogen and carbon
atoms of crude oil, however, would block neutrons from penetrating. Another possible
approach, muon detection, might work if daunting technical approaches could be
9 Thomas Cochran, William Arkin, and Milton Hoenig, Nuclear Weapons Databook, volume I:
U.S. Nuclear Forces and Capabilities, (Cambridge, MA: Ballinger, 1984) p. 32.
10 CRS Report RL32595, Nuclear Terrorism: A Brief Review of Threats and Responses, by
Jonathan Medalia, discusses how terrorists might acquire a nuclear device.

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overcome.11 Other candidate techniques include chemical sampling of oil for traces of
extraneous material, and preparing an acoustic profile of a ship when known to be “clean”
to compare with a profile taken as the ship nears port. The vast amount of oil in a
supertanker works against the former technique; the complex configuration of tanks on
a tanker works against the latter.
Securing Tankers. The difficulty of detecting a bomb aboard a tanker
underscores the importance of preventing bombs from being placed aboard tankers.
Securing tankers at loading terminals would likely involve setting and enforcing a security
perimeter (including underwater), and instituting measures to ensure personnel reliability.
Items brought on board a ship would have to be screened. A National Nuclear Security
Administration program, “Second Line of Defense,” screens people and baggage for
fissile material; similar technology might be used to secure tankers.
Securing tankers in port might not be adequate if terrorists could smuggle a bomb
onto a ship at sea. It may be possible to improve security by using surveillance aircraft
or satellites. Security may be a greater issue as tankers slow to navigate straits or
approach port. Several issues arise: (1) Would shippers let crew spend time to upgrade
security beyond current levels? VLCCs have small crews, perhaps 40 people, who may
have no time for added tasks. (2) If intelligence data indicated a plot to board a tanker at
sea to place a bomb, could a warning be passed without compromising U.S. intelligence
capabilities? (3) This scenario would require the connivance of the entire crew, or
silencing those who opposed the plot. Screening for personnel reliability may be the only
defense against this prospect.
Potential Oversight Questions and Options For Congress
Oversight Questions. Possible oversight questions include the following:
! What is the Administration’s view on the potential for terrorists to use an
oil tanker as a vehicle for a nuclear attack? To what extent has the
Administration considered this threat in planning for port and maritime
security?
! If considered a serious threat, what measures is the Administration
implementing to respond to it? When will they be in place? How much
funding is programmed for them over the next few years? Which areas
of detection technology may merit development?
11 Muons are subatomic particles produced when cosmic rays from space strike atoms in the
upper atmosphere. Some 10,000 muons per minute strike each square meter of Earth. They can
penetrate many meters of rock. Their path is bent slightly in proportion to the density and atomic
number (number of protons in the nucleus) of the material. Los Alamos National Laboratory has
conducted experiments to determine if muons can be used to detect fissile material in cargo
containers. The technique involves placing a flat-plate detector above and below the container
to measure how much the paths of individual muons are bent. Detectors would have to be scaled
up immensely to go from a container to a VLCC. Detection could be time-consuming: the level
of detail increases with number of muons, which increases with time. See Brian Fishbine, “Muon
Radiography: Detecting Nuclear Contraband,” Los Alamos Research Quarterly, Spring 2003.

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! Which executive branch office has overall responsibility for examining
or addressing this potential threat? What other executive offices have
responsibilities in this area? Is there adequate coordination among them?
Potential Options. Congress might consider options such as the following to
further explore the threat discussed in this report. If Congress found the threat credible,
it could:
! Clarify federal responsibility for tanker security by requiring a lead
federal agency for tanker security and making more explicit the
responsibilities of various federal agencies involved in tanker security.
! Create a Tanker Security Initiative (TSI) analogous to the Container
Security Initiative for improving containerized cargo security.12 TSI
might set security standards for tankers that transport oil to U.S. ports,
and for the ports where they load. Tankers not meeting the standards, or
that come from ports not meeting the standards, could be denied entry to
U.S. ports. Establishing such a regime would undoubtedly require
negotiations with other countries.
! Ensure that tankers are a focus of maritime domain awareness,
which refers to surveillance and communication systems that would
permit U.S. officials to have a comprehensive understanding at any given
moment of the location and identity of ships at sea.13
! Assure sufficient U.S. intelligence assets are focused on the threat and
possible indications of preparations for such an attack. Terrorists seeking
to acquire or build a bomb and smuggle it onto a tanker would need to go
through certain steps. Similarly, a terrorist bomb placed inside a tank of
crude oil might have certain signatures, such as a way to detonate the
bomb. The Intelligence Community could analyze such steps and
signatures, and be alert to signs of the most critical ones.
! Determine whether funding is adequate for technologies that hold
some prospect of detecting an atomic bomb aboard a tanker.
! Keep oil tankers away from U.S. ports by promoting the construction
of more offshore ports like LOOP.
! Improve international cooperation. Existing international agreements
and organizations that might focus on tanker security include agreements
for countering narcotics, crime, and piracy; the International Maritime
Organization, shipping associations, and Interpol; and the International
Ship and Port Facility Security Code. These efforts could supplement the
Proliferation Security Initiative (PSI), a multilateral effort for interdicting
ships at sea that are suspected of carrying weapons of mass destruction.
12 For more on the Container Security Initiative, see CRS Report RL31733, op cit, p. 12-13.
13 For more on maritime domain awareness, see CRS Report RL31733, op cit, p. 12.

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Ships available for PSI missions might respond to indications of tanker
security problems at sea.14 The United States could pursue increased
bilateral cooperation with oil-exporting states and countries under whose
flags tankers are registered. Potential measures include improved
perimeter security at oil-loading terminals and more rigorous background
screening and training of port workers and tanker crew members.
Should Congress conclude that proactive steps should be taken in this area, the issues
of who should pay and how funds should be collected would arise. Costs could be
covered by general revenues. Alternatives would be to charge a fee on ships landing oil
in the United States or to impose a tax on crude oil or petroleum products consumed in
the United States.
14 For more on PSI, see CRS Report RS21881, Proliferation Security Initiative (PSI), by Sharon
Squassoni.

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