The federal government has statutory obligations to regulate interstate commerce and securethe United States against terrorism. Therefore, Congress has a strong interest in federal regulationsand programs related to hazardous chemicals security. Since September 11, 2001, legislators,government agencies, and industry have been working to prevent terrorist attacks involvinghazardous chemicals. Their goal is to ensure the continued availability of such chemicals forcommercial use while reducing the risk of their exploitation by terrorists. Large quantities of hazardous chemicals are found in commercial facilities, marinetransportation, rail transportation, and highway trucking. (1) To date, Congressional attention has focused largely on the securityof hazardous chemicals transported by rail or tanker trucks, or stored at commercial facilities nearpopulated areas. As the nation's rail, truck, and chemical facility policies mature, Congress isreviewing federal policies related to marine transportation of hazardous chemical cargo. (2) In the 109th Congress, forexample, H.R. 2651 would establish or increase penalties for criminal or terrorist activities aroundports and marine vessels. S. 1052 includes provisions to increase general port security, includingports in foreign countries. In response to the overall security environment, Congress is likely to seeka broader understanding of hazardous chemical marine shipments and efforts to secure them. This report provides an overview of hazardous chemicals marine transportation in the UnitedStates. The report discusses the general risks from such marine transportation in the homelandsecurity context. It focuses on many of the hazardous chemicals with the greatest potential to affectthe public in a terrorist attack and the marine vessels that carry such chemicals. It summarizesfederal statistics on the hazardous chemical marine shipments in U.S. waters, including shipmentvolumes by type of chemical and port location. It provides a brief overview of relevant U.S.maritime security regulation. It raises security policy issues associated with these shipments,including risk uncertainties, security resources, and security effectiveness. The report concludes witha discussion of marine chemicals security as part of the nation's overall chemical security strategy. This report addresses marine shipments of a limited set of acutely hazardous chemicalcargoes that, if released, could potentially pose a catastrophic hazard to the general public. (Thespecific cargoes are defined in subsequent sections). The report does not examine other potentialmaritime security hazards such as petroleum products, biological agents, or container bombs, whichmay also be of interest to policymakers. (3) It focuses on threats to the general public from chemical releaseduring marine transport. It does not address marine attacks targeting economic activity or theenvironment. Due to the sensitive nature of the topic and legal limitations on the publication ofcertain proprietary shipping data, the report does not provide detailed statistics for the specifichazardous chemicals or ports of interest. Marine shipments of hazardous chemical cargo are potentially attractive terrorist targetsbecause these chemicals are acutely toxic or highly combustible, and are shipped in large volumes. They may represent a serious threat to human life and physical infrastructure if intentionally releasednear populated areas. Hazardous chemical marine vessels are also part of two "criticalinfrastructures" identified by the Bush Administration--the chemicals and transportationsectors. (4) For thesereasons, the protection of hazardous chemical shipments passing through U.S. waterways and portsis an important component of U.S. homeland security strategy. Although security experts widely acknowledge that marine shipments of hazardous chemicalsmay be attractive terrorist targets, no marine vessel carrying hazardous chemicals has been used byterrorists in an attack on civilians. Nonetheless, marine accidents involving such shipments in theU.S. and abroad have demonstrated their potential to impact nearby communities. Foreign terroristsalso have successfully attacked other types of marine vessels overseas. As discussed later in thereport, intelligence suggests that terrorists may have both the interest and capability to executehazardous chemical shipping attacks in the United States. Major accidents involving the marine transportation of hazardous chemicals are uncommon. (5) However,those that have occurred include some of the deadliest industrial accidents ever recorded. In 1917,for example, the explosion of the Mont-Blanc, carrying a cargo of explosives in the port of Halifax,killed over 1,900 people and seriously injured over 4,000 others. (6) The 1947 explosion of twocargo ships carrying ammonium nitrate and sulfur in Texas City, Texas destroyed the port, killingnearly 600 people and injuring another 3,500. (7) Due to improved safety practices and vessel construction, a marine accident as destructiveas the Texas City disaster has not occurred in the ensuing 60 years. However, serious incidentsinvolving chemical marine shipments have forced the evacuation of threatened coastal populations. These incidents include a 1985 fire aboard the Ariadne carrying 100 containers of toxic chemicalsin the port of Mogadishu, Somalia (8) ; a 1987 accident aboard the Cason carrying 1,200 tons offlammable, toxic, and corrosive chemicals near Cape Finisterre, Spain (9) ; and a 1999 fire aboard the Multitank Ascania carrying a cargo of vinyl acetate off the coast of Scotland. (10) These incidents did notresult in serious casualties among neighboring communities, but emergency responders had a highdegree of concern for public safety as indicated by the associated evacuations. Although terrorists have never used a marine cargo vessel to launch a chemical attack on thegeneral public, both international combatants and domestic terrorists tried to use explosives torelease chemicals from land based manufacturing and storage facilities during the 1990s. Most ofthese attempts were in foreign war zones such as Croatia. They included attacks on a plantproducing fertilizer, carbon black, and light fraction petroleum products; other plants producingpesticides; and a pharmaceutical factory using ammonia, chlorine, and other hazardous chemicals.All of these facilities were close to population centers. In the United States, there were at least twoinstances during the late 1990s when criminals attempted to release chemicals from similar facilities.One incident involved a large propane storage facility in California, and the other a gas refinery inTexas. (11) Terrorists have directly targeted marine vessels, mainly to destroy the vessel or cargo. InJune 2002, Moroccan authorities foiled an Al-Qaeda plot to attack U.S. and British warships, andpossibly commercial vessels, in the Straits of Gibraltar. (12) In October 2002, the oil tanker Limburg was successfullyattacked off the Yemeni coast by a bomb-laden fishing boat. (13) Foreign governmentshave reportedly expressed concerns about terrorist groups commandeering a hazardous chemicalvessel and "crashing it into a port." (14) In the United States, the Department of Homeland Security (DHS) has been consistentlyconcerned about the security of chemicals infrastructure, including chemical tanker ships. (15) The Homeland SecurityCouncil included terrorist attacks on ships carrying flammable and toxic chemical cargoes in a U.S.port among the hazard scenarios it developed as the basis for U.S. homeland security nationalpreparedness standards. (16) The President's National Strategy states that "much of the portsystem represents a significant protection challenge, particularly in the case of high consequencecargo." (17) One type of hazardous marine cargo--liquefied natural gas (LNG)--has received particularpublic attention. The DHS reportedly included LNG tankers among a list of potential terrorist targetsin a security alert late in 2003. (18) The DHS also stated that "the risks associated with LNGshipments are real, and they can never be entirely eliminated." (19) A 2004 report by SandiaNational Laboratories considered potential terrorist attacks on LNG tankers "credible andpossible." (20) TheSandia report identified LNG tankers as vulnerable to ramming, pre-placed explosives, insidertakeover, hijacking, or external terrorist actions (such as a Limburg -type attack, a missile attack, oran airplane attack). (21) Homeland Security Presidential Directive 7 (HSPD-7) directs federal homeland securityactivities to focus on terrorist attacks that could cause "catastrophic health effects or mass casualtiescomparable to those from the use of a weapon of mass destruction." (22) For purposes of thisreport, hazardous chemical cargo is chemicals carried aboard a commercial marine vessel that, ifaccidentally released or combusted, could, under certain circumstances, pose a catastrophic hazardto the general public. Typically, such hazards could include poisoning, asphyxiation, chemicalburns, or thermal burns. In some cases, a single chemical could present a combination of thesehazards. Numerous federal standards identify potentially hazardous chemicals. With respect topublic security, relevant standards are promulgated by the Department of Transportation (DOT), theCoast Guard, and the Environmental Protection Agency (EPA). The DOT regulates the transportation of all hazardous materials under the HazardousMaterials Transportation Act of 1975 ( P.L. 93-633 ) and subsequent amendments. The act empowersthe Secretary of Transportation to designate as "hazardous" any particular quantity or form ofmaterial that "may pose an unreasonable risk to health, safety and property when transported incommerce." The DOT defines and classifies hazardous materials in 49 C.F.R. Â§ 172.101. TheDOT's list includes thousands of materials--including toxic, radioactive, corrosive, explosive, andflammable materials--which could potentially be shipped. The DOT groups individual materials bytype of hazard (e.g., inhalation poisoning) but not necessarily by relative degree of hazard. The DOTdoes provide a ranking of relative hazard by general class or division in 49 C.F.R. Â§ 173.2a. Thisranking is summarized in Appendix 1 . In addition to its general hazardous material safety regulations, the DOT requires shippersof certain "highly hazardous" cargo to develop security plans in 49 C.F.R. Â§ 172.8.