Pipeline transport are usually buried. The oil is moved through the pipelines by pump stations along the pipeline. Natural gas (and similar gaseous fuels) are lightly pressurised into liquids known as Natural Gas Liquids (NGLs). Natural gas pipelines are constructed of carbon steel. Hydrogen pipeline transport is the transportation of hydrogen through a pipe. Pipelines conveying flammable or explosive material, such as natural gas or oil, pose special safety concerns and there have been various accidents. Pipelines can be the target of theft, vandalism, sabotage, or even terrorist attacks. In war, pipelines are often the target of military attacks. It is uncertain
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