RPT-North Dakota's new oil train safety checks seen missing risks
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By Patrick Rucker
WASHINGTON, March 31 (Reuters) - New regulations to cap vapor pressure of North Dakota crude fail to account for how it behaves in transit, according to industry experts, raising doubts about whether the state's much-anticipated rules will make oil train shipments safer.
High vapor pressure has been identified as a possible factor in the fireball explosions witnessed after oil train derailments in Illinois and West Virginia in recent weeks.
For over a year, federal officials have warned that crude from North Dakota's Bakken shale oilfields contains a cocktail of explosive gas - known in the industry as 'light ends.'
The new rules, which take effect on April 1, aim to contain dangers by spot-checking the vapor pressure of crude before loading and capping it at 13.7 pounds per square inch (psi) - about normal atmospheric conditions.
The plan relies on a widely-used test for measuring pressure at the wellhead, but safety experts say gas levels can climb inside the nearly-full tankers, so the checks are a poor indicator of explosion risks for rail shipments.
It is "well-understood, basic physics" that crude oil will exert more pressure in a full container than in the test conditions North Dakota will use, said Dennis Sutton, executive director of the Crude Oil Quality Association, which studies how to safely handle fossil fuels.
Ametek Inc, a leading manufacturer of testing equipment, has detected vapor pressure climbing from about 9 psi to over 30 psi - more than twice the new limit - while an oil tank is filled to near-capacity. (Graphic: reut.rs/1EHChG4) Continued...