What are the chances?

摘要

It is, on the face of it, a startling statistic: more crude oil was spilt from rail tank cars last year in the US than in the previous 38 years put together. Data collected by the US Pipeline and Hazardous Materials Safety Administration (PHMSA) show that 1.15m gal (27,380 bbl) of crude was spilled in 2013, in comparison to 800,000 gal (19,000 bbl) in the period 1975 to 2012. While that statistic is initially alarming, it must be put into perspective. According to the Association of American Railroads (AAR), the six Class I railroads in the US (including the US operations of the two Canadian railroads) originated a total of 9,500 carloads of crude oil in 2008. By 2012 that figure was up to 234,000 carloads and the latest estimate for 2013 was some 400,000 carloads.