Keystone pipeline raises concerns after third major spill in five years

An investigation into the pipeline's largest spill is under way in Kansas as a recent report points to a deteriorating safety record

The Keystone pipeline, which traverses 2,600 miles from western Canada through the central US, leaked an estimated 14,000 barrels of oil, more than half a million gallons, into a creek in Washington county, Kansas, on 7 December. The incident was the largest onshore oil spill since at least 2013, the Keystone pipeline's third major spill in the last five years, and the largest since it began operating in 2010.

It is also the case that previous estimates from earlier spills on the pipeline have turned out to be much larger than the initial estimates.