Preparing for LNG by Rail Tank Car: A Readiness Review (2022)

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1 Executive Summary As the domestic production of natural gas and demand from export mar- kets has grown over the past decade, so too has demand for producing and transporting liquefied natural gas (LNG). LNG is regulated as a hazardous material when transported because it is a cryogenic liquid and flammable when released as a gas. In July 2020, the U.S. Department of Transporta- tion’s Pipeline and Hazardous Materials Safety Administration (PHMSA) and Federal Railroad Administration (FRA) issued a rule authorizing the transportation of LNG by rail tank car for the first time. Shipments are authorized in an upgraded version of a common cryogenic tank car, the DOT-113C120W9. As of July 2022, LNG had yet to be shipped by tank car, and no upgraded tank cars had been produced for the in-service cryo- genic fleet. This study’s purpose is to identify areas where additional investigation, analysis, and monitoring may be warranted so that industry and regulators can better assess LNG’s risks in rail transportation and make choices about how best to manage those risks. To do so, the expert committee charged with conducting the study reviewed the hazards associated with LNG’s cryogenic and flammable properties, the experience with shipping LNG by truck and ship, the safety assurance frameworks established for ensuring that LNG and other hazardous materials shipments are transported without incident, and the state of emergency response planning and preparation for hazardous materials incidents in general and for LNG in particular. The committee also reviewed results from fire testing of a cryogenic portable tank that shares some of the DOT-113 tank car’s design features and impact testing of the upgraded DOT-113 tank car.

2 PREPARING FOR LNG BY RAIL TANK CAR On the basis of this review, the committee finds that LNG has a long history of safe transportation in other modes and that PHMSA, FRA, and industry have started to take precautions to ensure the safe transportation of LNG by rail tank car. However, more than 18 months after PHMSA’s authorization of these movements little has changed with regard to the ship- ment of LNG by rail, and there remains a great deal of uncertainty about how much LNG will be transported, when, and over which routes. In the committee’s view, this lull provides an opportunity to further assess these precautions and prepare for an effective response to incidents and emergen- cies that may arise. Furthermore, in having reviewed the results of the re- cent impact and fire tests, the committee believes that further investigation and analyses of the DOT-113C120W9 tank car are warranted to ascertain its resistance to overheating and a high-pressure release arising from LNG’s distinctive cryogenic and flammable properties. For these purposes, the committee offers the following recommendations. Recommendation 1: PHMSA and FRA should plan an LNG safety assurance initiative that would be launched before LNG tank cars are put in service. The safety assurance initiative would actively monitor initial plans for and early patterns of LNG traffic activity, including the locations and routes of shipments, the number and configuration of tank cars in trains, and reports of incidents involving a tank car or train carrying LNG. The initiative would enable the more timely and targeted development and dissemination of resources, direction, and guidance, with interventions as necessary, to ensure that • Emergency responders in communities expected to have high levels of LNG rail traffic activity have the needed guidance, training, and specialized resources to respond to potential incidents; • Personnel engaged in the transfer and transportation of LNG by rail are qualified and properly trained for safe shipment handling, operations, and emergency actions; • Protocols for train makeup, handling, and operations are suited to LNG shipping patterns, such as in single cars, large blocks, or unit trains, for instance, as informed by the results of longitudinal train dynamics and operation simulation software; • Track inspection protocols are appropriate for, and targeted to, routes with significant LNG traffic; and • The risk assessment and management analyses required by regula- tion (49 CFR § 172.820, Additional planning requirements for transportation by rail) are comprehensive and well informed. While the surveillance and monitoring of anticipated and actual traffic activity will need to wait until more firm plans are made for LNG’s

EXECUTIVE SUMMARY 3 transportation by tank car, the many preoperational aspects of this safety assurance initiative (e.g., the development of emergency response guidance) would need to commence well in advance of when those plans are executed. Recommendation 2: PHMSA and FRA should review the DOT- 113C120W9 tank car specification to ensure that it adequately ac- counts for the cryogenic and thermal properties of LNG that could contribute to a tank release and cascading impacts. In particular, the agencies should obtain data needed to assess • The capacity of the pressure relief devices to vent sufficient LNG when the tank car is engulfed in an LNG fire, taking into account derailment conditions, such as a rollover, that could degrade this capacity; • The effects of adding more and different types of insulation in the annular space to ensure sufficient performance of the multilayer insulation system when the tank car is exposed to heat flux and direct flame impingement from an LNG fire; and • The potential for the outer tank to experience cryogenic brittle fail- ure and loss of vacuum insulation when exposed to an LNG pool. The outcomes of this recommended review, should they raise con- cerns, could affect the design specifications for pressure relief devices, insulation, and the type of outer tank steel, as well as have further implications for other design features such as shell thickness and head protection. In November 2021, PHMSA proposed amending its earlier rule to tem- porarily suspend the authorization of tank car movements of LNG, point- ing to the importance of completing additional tank car testing and analyses and responding to a mandate in Executive Order 13990 for PHMSA to review recent actions that could be obstacles to federal policies promoting public health and safety, the environment, and climate change mitigation. The committee did not assess this proposal to suspend the rule, nor was it tasked with examining and reaching conclusions about the risk and desir- ability of transporting LNG by rail. The measures recommended in this report are intended to inform follow-on risk assessments and choices about how best to ensure the safe transportation of LNG by rail tank car in the manner demonstrated by marine vessels and trucks for many decades.