All crude oils, as well as gasoline and diesel fuel, contain benzene. Oil to be shipped on Keystone XL will include bitumen from the oil sands in Canada that has been diluted with lighter oils. Most often, these lighter oils used as diluents will be natural gas liquids.
Like other oil pipelines in service in Nebraska, Keystone XL will deliver oil from U.S. sources and from the Canadian oil sands. Oils to be shipped on Keystone XL include light sweet crudes, synthetic crude oils (partially refined bitumen), and diluted bitumen. Concentrations of benzene and similar components that result in the requirements to meet safety requirements in the shipment (including toluene, ethyl benzene, and xylene, typically abbreviated with benzene as BTEX) are present in the oils shipped on Keystone XL at a lower concentration than in diesel fuels or gasoline.
For more information: Additional information is available in Section 6.3 of the NDEQ “Draft Evaluation Report on the Keystone XL Pipeline Nebraska Reroute,” available from the NDEQ homepage. Information is also available in the Final EIS, Section 3.13.