TIOGA, N.D. -- The oil on the train that derailed near Heimdal on Wednesday had a vapor pressure substantially lower than the standards in North Dakota’s new oil conditioning order, a Hess Corp. spokesman said Thursday.
Hess, which owned the railcars that caught fire in Wednesday’s derailment, has been in compliance with the state’s rules, said Alison Ritter, spokeswoman for the Department of Mineral Resources.
The railcars were loaded at the company’s Tioga Rail Terminal, Hess spokesman John Roper said.
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Documentation obtained by the Department of Mineral Resources shows that oil loaded Wednesday at the Tioga facility had a vapor pressure of 10.83 pounds per square inch.
The state’s conditioning order that took effect in April requires oil to be conditioned so it has a vapor pressure no greater than 13.7 pounds per square inch.
Oil from the Tioga rail facility has tested at 12.44 psi, 11.08 psi and 11.18 psi, according to April tests submitted by Hess to the Department of Mineral Resources.
“So far everything has been in compliance,” Ritter said.
The conditioning order aims to reduce the volatility of Bakken crude oil so that it is similar to unleaded gasoline, Ritter said.
Six cars derailed Wednesday morning near Heimdal, 80 miles southeast of Minot, with four cars catching fire.
“By all accounts, it looked like a much different scene than Casselton as far as the fire and the intensity of the fire,” Ritter said.
The volatility of Bakken crude has been examined closely in the wake of explosive derailments in Casselton and elsewhere in North America in recent years.
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In January 2014, after the Casselton explosion, the Pipeline and Hazardous Materials Safety Administration issued a safety alert to warn emergency responders and the public that Bakken crude may be more flammable than traditional heavy crude oil.
About 99 percent of the vapor pressure tests that have been submitted since the new oil conditioning order took effect have been in compliance, the Department of Mineral Resources has said. Those that are out of compliance are given 48 hours to adjust equipment and retest.
Roper said Hess is standing by to provide assistance to BNSF Railway on the emergency response.
Hess owns nearly 1,000 railcars that were purchased in 2011, Roper said. All of the cars are CPC-1232 cars, he said.
Hess does not own any DOT-111 cars, which were involved in the derailments in Casselton as well as a deadly derailment in Quebec.
“We were the first in the Bakken to have a whole new fleet,” Roper said.
The tank cars involved in Wednesday’s derailment were unjacketed CPC-1232 cars, said Michael Trevino, a spokesman for BNSF.
The CPC-1232 has a half-inch shell plus top and bottom fitting protection, while the DOT-111 car has a 7/16 shell, Trevino said.
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It took the National Transportation Safety Board until April, 15 months after the Casselton derailment, to release documents related to the Casselton incident. The agency concluded that a better inspection of old tank car axles might have prevented the collision of the soybean train and the oil train.
Last week, the United States and Canada announced new safety rules for trains carrying oil, including a rapid phaseout of older tank cars. The DOT-111 cars will be phased out within three years and CPC-1232 cars without reinforced hulls - the ones involved in the latest derailment - will be phased out by 2020.
Other rules include restricting the speed of oil trains to a maximum of 50 miles per hour and requiring electronically controlled pneumatic brakes that trigger all axles simultaneously.
