An oil train derailment and spill in northwest Illinois poses an "imminent and substantial danger" of contaminating the Mississippi River, the U.S. Environmental Protection Agency said Saturday.
The spill from the derailment, which occurred Thursday, also threatens the Galena River, a tributary of the Mississippi, and the Upper Mississippi National Wildlife and Fish Refuge, one of the most complex ecosystems in North America.
The EPA said it couldn't estimate how much oil was spilled, but the 21 derailed cars of the BNSF Railway train contained 630,000 gallons of Bakken crude from North Dakota. Small fires from the wreckage continued to burn Saturday.
Earlier Saturday, another oil train derailed and caught fire near Gogama, Canada, bringing to five the total number of such derailments in the U.S. and Canada in as many weeks.
The safety of trains carrying flammable materials has become an issue as the introduction of new drilling technology has allowed the development of crude oil deposits far from traditional pipelines, particularly in the Bakken formation in North Dakota.
Rail has become the preferred way to transport that crude to refineries, with railroads moving about 500,000 carloads of oil last year, according to industry estimates, up from 9,500 in 2008. One tank car holds 30,000 gallons.
But recent derailments have cast doubt on the effectiveness of safety efforts and suggest that no tank car in service on the North American rail system is tough enough to resist damage in relatively low-speed derailments.
According to the Federal Railroad Administration, which is investigating the Illinois derailment, the 105-car train was traveling at just 23 mph when it left the tracks, well below the maximum speed allowed. The damaged tank cars were newer CPC-1232 tank cars, which are supposed to be safer than previous ones, but have failed in at least four derailments this year and at least two in 2014.
Saturday's derailment of a Canadian National Railway train took place about 20 miles from where another oil train derailed on the same rail line three weeks ago. The railroad said on Twitter Saturday afternoon that five cars were in a local waterway, some of them on fire. About 264,000 gallons of oil was released in the Feb. 14 derailment. The Transportation Safety Board of Canada is investigating both accidents.
The Illinois derailment is the second in three weeks on U.S. rails. On Feb. 16, 28 cars of a 107-car CSX train derailed in Mount Carbon, W.Va., and 19 caught fire. One house was destroyed and more than 100 residents were evacuated for four days. Many residents and first responders saw columns of fire rising hundreds of feet in the air as several of the tank cars ruptured from heat exposure.
A Canadian Pacific train carrying ethanol derailed Feb. 4 along the Upper Mississippi north of Dubuque, Iowa. The EPA estimates that about 55,000 gallons spilled, some of which burned and some of which was recovered from the river.