Construction of the Trans-Alaska Pipeline System with the Denali Fault, a major cause of earthquakes, and with large amounts of permafrost. In 1969, the unincorporated Trans-Alaska Pipeline System group drilled a series of core samples north of the Brooks Range that demonstrated how ubiquitous the permafrost was along the route. This forced the design of an elevated pipeline, which was tested in a loop built near Barrow. This elevation required the pipeline to be insulated, since extreme cold temperatures caused the metal to become brittle, even when hot oil was being pumped through the pipeline. After ecological objections forced subterranean pipeline crossings (in order to allow
Construction of the Trans-Alaska Pipeline System cost $1.4 billion. The percentage of the pipeline owned by various companies has changed over time, but as of 2009, the primary owner was BP, which controls 46.93 percent of the pipeline. Second is ConocoPhillips Transportation Alaska Inc. with 28.29 percent, followed in order by ExxonMobil (20.34 percent), Koch Alaska Pipeline Company (3.08 percent), and Unocal Pipeline Company (1.36 percent). The pipeline also has had a human toll. Thirty-two Alyeska or contract workers were killed during the construction project. That figure does not include common carrier fatalities. Since the pipeline began operating in 1977, 10 people have been killed while