"The oil-pipeline leak that fouled a stretch of California coastline last week reflects a troubling trend in the nation's infrastructure: As U.S. oil production has soared, so has the number of pipeline accidents.

Since 2009, the annual number of significant accidents on oil and petroleum pipelines has shot up by almost 60 percent, roughly matching the rise in U.S. crude oil production, according to an analysis of federal data by The Associated Press.

Nearly two-thirds of the leaks during that time have been linked to corrosion or to material, welding and equipment failures, problems often associated with older pipelines, although they can occur in newer ones, too. Other leaks were blamed on natural disasters or human error, such as a backhoe striking a pipeline."

Henry C. Jackson and David A. Lieb report for the Associated Press May 24, 2015. [2]