Floodwaters from the swollen Little Rock River are thought to have caused the derailment of up to 40 rail cars in a train carrying crude oil from Alberta south of Doon, Iowa, on June 22. Up to 230,000 gallons (1 million litres) of crude are thought to have leaked into the floodwaters, leading to fears for drinking water supplies in cities downstream of the leak site.
Railroad operator BNSF said hazardous materials and environmental experts on the scene and had begun a cleanup within hours of the derailment.
The floods were caused by two downpours in the previous 48 hours and local officials said the spreading waters could have compromised the track and caused the derailment.
The oil leak caused concern downstream as far south as Omaha, Nebraska, about 150 miles from the derailment site. The spill reached the Rock River, which joins the Big Sioux River before merging into the Missouri River at Sioux City.
Omaha’s public water utility, Metropolitan Utilities District, said it was monitoring pumps it uses to pull drinking water from the Missouri River.
A spokesman for the Iowa Natural Resources Department said they were trying to determine how fast the oil was travelling south, which was made difficult given that the river, instead of being 100 yards wide, was now up to a half-mile wide.
On June 17 another derailment in Princeton, Indiana, led to a mandatory evacuation. Train operator CSX Transportation said propane caught fire after the crash, and there were no reports of injuries.