Editing Pipeline (section)

===Spill frequency-volume===
Although the [[Pipeline and Hazardous Materials Safety Administration]] (PHMSA) has standard baseline incident frequencies to estimate the number of spills, TransCanada altered these assumptions based on improved pipeline design, operation, and safety.<ref name="potential"/> Whether these adjustments are justified is debatable as these assumptions resulted in a nearly 10-fold decrease in spill estimates.<ref name="stansbury"/> Given that the pipeline crosses 247 miles of the Ogallala Aquifer,<ref>{{cite web|last=US State Dept|title=Environmental Analysis: Water Resources|url=http://www.keystonepipeline-xl.state.gov/clientsite/keystonexl.nsf/09_KXL_FEIS_Sec_3.3_Water_Resources.pdf?OpenFileResource|archive-url=https://web.archive.org/web/20230909100929/https://www.keystonepipeline-xl.state.gov/clientsite/keystonexl.nsf/09_KXL_FEIS_Sec_3.3_Water_Resources.pdf?OpenFileResource|url-status=dead|archive-date=September 9, 2023|access-date=2 November 2011}}</ref> or 14.5% of the entire pipeline length, and the 50-year life of the entire pipeline is expected to have between 11 – 91 spills,<ref name="stansbury"/> approximately 1.6 – 13.2 spills can be expected to occur over the aquifer. An estimate of 13.2 spills over the aquifer, each lasting 14 days, results in 184 days of potential exposure over the 50 year lifetime of the pipeline.
In the reduced-scope worst-case exposure scenario, the volume of a pinhole leak at 1.5% of max flow-rate for 14 days has been estimated at 189,000 barrels or 7.9 million gallons of oil.<ref name="stansbury"/> According to PHMSA's incident database,<ref>{{cite web|last=PHMSA|title=Incident Statistics|url=http://www.phmsa.dot.gov/hazmat/library/data-stats/incidents|access-date=2 November 2011}}</ref> only 0.5% of all spills in the last 10 years were >10,000 barrels.