A handful of major accidents, including a 2001 freight train derailment near Minot, N.D., drove home the activists' point. In that case, five tank cars carrying ammonia gas broke open, releasing toxic fumes that killed one and injured 1,441, federal data show. In 2005, a train collision in Graniteville, S.C., broke open one tank car loaded with 90 tons of chlorine, releasing about two-thirds of the gas. Nine died and 252 were injured.
Following the North Dakota accident, the National Transportation Safety Board (NTSB) in a 2004 study concluded that more than half of the 60,000 rail tank cars used to transport hazardous materials at that time were not built according to standards and were susceptible to rupture in the case of an accident.
Overall, there were 310 rail accidents involving hazardous-materials spills during the past decade, Federal Railroad Administration rail-accident data show. Among those, 31 of the accidents resulted in 22 deaths and 1,926 injuries. In the other 90 percent of such accidents, no one was harmed. Over the five-year period from 2007 to 2011, such hazmat-rail accidents fell to an average of 26 per year, down 17 percent from the previous five-year period. In 2011, there were 20 such accidents, with 17 so far this year.
"We have been seeing a positive trend in this area," says Holly Arthur, a spokesman for the Association of American Railroads (AAR), which represents major railroads. "Today 99.97 percent of hazmat-rail shipments reach destination without a release."
Rail accidents with hazmat releases have fallen 83 percent since 1980 and 43 percent since 2000, an AAR analysis of the federal data shows.