The U.S. Departments of Transportation and Energy have suggested in a report to Congress that regulation to define crude-by-rail movements using crude oil’s vapor pressure isn’t needed.
The issue of vapor pressure as a factor in potentially restricting crude-by-rail movement is a hot topic because the state of Washington enacted a law in 2019 setting vapor pressure limits, while other states have lobbied the federal government to pursue a similar mandate. Washington state’s crude-by-rail law calls for crude oil that will be unloaded in the state to meet a Reid Vapor Pressure limit of 9 pounds per square inch (psi). The law doesn’t ban crude-by-rail movement in the state, and the state has argued that the law is meant to reduce the risk of explosions or potentially fatal derailments.
But crude-producing states such as North Dakota have argued that Washington state’s mandate violates interstate commerce rules and effectively bans Bakken crude from being transported through the state. The federal government is still considering a request by North Dakota and Montana to weigh in on the issue.
The Departments of Energy and Transportation, which outlined their findings in an April report to Senate and House members, based their conclusions on a commissioned study from Sandia National Laboratories. The Pipeline and Hazardous Materials Safety Administration (PHMSA) and Transport Canada were also involved in commissioning the study.
“Based on the results of the study, which assessed vapor pressure at it affects the thermal hazards from the combustion events studied, the Department of Energy [DOE] and the Department of Transportation [DOT] find that no further regulation by the Secretary of Transportation or the Secretary of Energy or further legislation is necessary to improve the safe transport of crude oil with specific regard to vapor pressure,” the April report said.
The report from the two federal agencies said the Sandia research compared several commercially available, industry standard sampling and analysis methods to a baseline instrument system from the U.S. Strategic Petroleum Reserve to determine the accuracy of evaluating crude oil vapor pressure and pressurized whole oil composition.
The researchers tested crude oils that ranged in vapor pressure and light ends content observed among domestic conventional and nonconventional crudes. The results were analyzed within the context of common liquid hydrocarbon fuels whose combustion properties overlap and exceed the vapor pressure of the tested crude oils.
According to the report’s executive summary, the research found that “the similarity of pool fire and firehall burn characteristics pertinent to thermal hazard distances of the three oils studied indicate that vapor pressure is not a statistically significant factor in affecting these outcomes. Thus, the results from this work do not support creating a distinction for crude oils based on vapor pressure with regard to these combustion events.”
The federal government’s response to the vapor pressure limits is still pending, but the American Fuel & Petrochemical Manufacturers (AFPM) supported the report’s findings.
“The Sandia report confirms that the vapor pressure (VP) of crude in rail transport has no impact on the frequency or consequences of a derailment, and that the results of the Sandia study do not support creating a new regulatory distinction for crude oils based on vapor pressure,” said Rob Benedict, senior director of petrochemicals, transportation and infrastructure at AFPM.
He continued, “These findings, based on three years of extensive study, further demonstrate that DOT/PHMSA should rescind its open rulemaking to set a nationwide VP standard and that the state of Washington’s unlawful attempt to regulate the transportation of crude oil based on VP is flawed and does not enhance rail safety. … Though efforts at the federal and state level to implement vapor pressure limits have always lacked the scientific evidence to support such an action, the findings of the Sandia study confirm that such an action has no basis in sound science. To address the root cause of derailments that release hazardous materials, DOT must refocus its efforts on improving track integrity and reducing human error in rail operations.”
