NAS: concerns remain about rail transport for energy liquids, gases; pipeline, maritime have more comprehensive safety system in place
Pipelines and barges have accommodated major portions of the growth in domestic energy liquids and gases, and they have done so without major new safety problems and within the basic framework of their longstanding regulatory and safety assurance systems. The committee that carried out the study and wrote the report stressed that to the credit of transportation service providers from all of the modes as well as their safety regulators, the vast majority of these energy supplies have been transported without incident, enabling the country to capitalize on its new energy resources and manage the safety risks associated with its transportation.
The country’s increased production of crude oil, natural gas, and corn-based ethanol created unforeseen demands and safety challenges on their long-distance transportation via pipelines, tank barges, and railroad tank cars. When this study commenced in late 2015, a national debate was underway about whether the domestic energy revolution was placing stress on the transportation system that would sacrifice safety. Railroad tank cars and tank barges were hauling oil and fuel ethanol in increasingly larger quantities and over longer distances, often on routes passing through communities that had little, if any, experience with regular and large quantities of flammable liquids traffic.
In light of these changes, the National Academies, under the auspices of the Transportation Research Board, sponsored this study of the three major long-distance modes of energy transportation. The study makes policy recommendations that can help reduce the likelihood of future incidents involving the transportation of these domestic energy supplies as well as ensure an effective emergency response when incidents do occur.
The committee noted in its report that it focused on the individual safety concerns for each of the three modes of transportation and highlighted the difficulties in making direct comparisons of safety performance. One reason, for example, is that some modes of transportation are not viable alternatives in some regions and for some shipments.
The committee found that railroads have an opportunity to create a more robust safety assurance system for moving crude oil and ethanol, one that resembles those of the maritime and pipeline carriers. Prior to 2005, railroads had little experience carrying ethanol and crude oil in large quantities. The surge in domestic production of ethanol resulted in a glut of energy resources in parts of the country that lacked sufficient barge and pipeline takeaway capacity. Therefore, railroads began to transport hazardous energy liquids in tank cars that had not previously carried these flammable materials in bulk and with shippers that lacked experience transporting them. In response to derailments, the focus of industry and regulators was on reducing the severity of incidents by making relevant tank cars more crashworthy and resistant to thermal failure.
The committee determined that incomplete understanding of the dynamics of tank-car unit train derailments and a lack of clear guidelines and resources for state and local emergency responders continues to present safety risks.
As the tank cars that are compliant with new design specifications are being phased in, tank cars built to older specifications that are less crashworthy and less resistant to thermal failures may continue to be used for flammable liquids traffic for several years. Preventing the derailment of these cars is imperative, the committee said.
Post-incident investigations of severe flammable liquids train derailments indicate track wear and defects are common causal factors. Questions remain about the technical basis for track inspection standards, which set an allowable failure rate, and whether these allowable rates and repair priorities should be adjusted for routes that continue to be used by tank-car unit trains.
In addition, the committee found that emergency response preparedness has improved but with geographic variability, and opportunities for improvement remain.
Because trains moving crude oil and ethanol remain a relatively a new phenomenon, many of the communities traversed by this traffic lack familiarity with responding to large-scale incidents involving trainloads of flammable liquids.
Industry and government authorities face a continuing challenge in ensuring that appropriate response procedures are widely known and that existing training opportunities are exploited, especially among rural communities that are served by volunteer fire departments.
Clear guidelines are lacking on the kinds of traffic data that railroads should be providing state and local agencies to prepare for energy liquids transportation emergencies.
Further complicating matters, information sharing among emergency planning agencies in some states differ, making it unclear if this information is being transmitted to the first responders.
Between 2010 and 2016, oil transmission pipeline mileage grew by more than 40%. The committee said that incident rates have been generally stable, with year-to-year fluctuations stemming from periodic high-consequence events that are sufficiently rare as to limit judgments about their underlying risk.
Although the committee found no new safety problems have emerged from the increased use of pipelines transporting larger amounts of domestic oil and gas, substantially more pipeline mileage and higher traffic volumes may result in more pipeline releases over time, simply because of the increase in exposure. The safety impact, however, is likely to depend on the extent to which new pipeline technologies, leak monitoring systems, and more vigilant and capable integrity management programs are effective in protecting the newer pipelines and the older ones that connect to them.
When the committee examined the safety record of energy liquids movement by waterways, it found no reports of ethanol or natural gas liquids releases over the past 10 years and only rare reports of crude oil releases. A series of incidents 30 years ago led to statutory and regulatory safety reforms that produced a robust and anticipatory safety culture that has dealt well with fluctuations in the demand for oil and other energy liquids and can serve as a model for other energy transport modes.
Railroad industry and regulators should strive to make the safety assurance system for energy liquids and gas transportation more anticipatory, responsive, and risk-informed, the committee said. To do so, industry and regulators will need to share information with emergency preparedness planners and first responders, develop more robust risk analytics, create and apply incentives to further the use of automation and other technological innovations for monitoring the safe operation and condition of equipment and infrastructure, and regularly review the effectiveness of safety regulations.
To that end, the committee made a series of recommendations for the US Department of Transportation’s Pipeline and Hazardous Materials Safety Administration (PHMSA).
The committee said PHMSA should undertake a comprehensive review of the successes and failures in responding to transportation safety challenges since 2005, in order to inform the development of more anticipatory and robust safety assurance systems.
PHMSA should also ensure federal emergency preparedness grant allocations are responsive to the needs of communities that face new and unfamiliar risks as a result of changes in energy liquids and gas shipments, review the extent that emergency responders are taking advantage of training opportunities, and tailor programs to enable and incentivize higher levels of participation.
PHMSA and other safety regulators should encourage pipeline, barge, and rail carriers to make greater use of quantitative risk analysis tools, for instance, to inform decisions about priorities for maintenance and integrity management of the equipment and infrastructure and about the routing of energy liquids by rail.
The Federal Railroad Administration (FRA) should enable and incentivize more frequent and comprehensive inspections of rail routes with regular energy liquids traffic as well as enable the use of new capabilities in sensor, high-resolution imaging, and autonomous systems technologies.
PHMSA and FRA should take advantage of the increased experience with tank-car unit train movements, including accident experience, to systematically model the full array of factors that can give rise to and affect the severity of flammable liquids train crashes, including the propagation of internal rail defects and the kinetics that arise from multi-car derailments.
National Academies of Sciences, Engineering, and Medicine. 2017. Safely Transporting Hazardous Liquids and Gasses in a Changing U.S. Energy Landscape. Washington, DC: The National Academies Press. doi: 10.17226/24923.