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
Central Europe Pipeline System out against a part of the pipeline in Southern-Germany by Red Army Faction sympathisers. At the end of the Cold War the system was significantly reduced as various military airports that used the system were closed, such as Bitburg Air Base and Soesterberg Air Base. However, in some other places expansion of the pipeline continued and in October 2008 construction of of additional pipeline was completed between Aalen and Leipheim. Since 1959, excess capacity of the pipeline may be used by civilian users. Currently, around 90% of the fuel transported through the system is for civilian users, customers including various