The trains crashed about 5:30 a.m. near Dresbach in southeastern Minnesota. One rail car struck a 1,000-gallon propane tank attached to a switching station, causing a small leak that was stopped by early afternoon, authorities said.
The crash involved a freight train with three locomotives, three loaded cars and 90 empty cars, and a shorter train called a "yard switcher" with two locomotives and 15 cars loaded with fertilizer, LoVecchio said.
Thirteen cars from each train derailed.
Three cars were leaking liquid nitrogen, a farm fertilizer, but the material was contained around the cars and none was reaching the river, he said.
LoVecchio said crews were working through the night on the cleanup, but it wasn't known when the line would reopen to traffic. Trains were able to detour over sister railways, he said.
About 25 disabled veterans at the nearby Mosher Veterans Rest Home near Dresbach were evacuated for several hours as a precaution because of the leak but returned home by late afternoon, said Joyce Tlougan, deputy director of Winona County Emergency Management.
One train engine was partially submerged in the Mississippi River, Tlougan said. It wasn't clear whether any of the cars contained hazardous materials or were leaking anything into the river, she said.
The railroad dispatched hazardous material professionals to the scene, LoVecchio said.
The locomotive that did not end up in the water was leaking diesel fuel but the fluid was contained on land, Tlougan said.
Four workers operated the two trains. Two were taken to a hospital as a precaution, but all four were "safe and accounted for," LoVecchio said.
The trains were traveling toward each other on the single tracks, although it's not clear why, Tlougan said.
LoVecchio said the line includes a "siding where one train would pass another," but he did not know what role, if any, that may have played in the crash.
"They are telling me one day (of disruption)," Kamrowski said. "I have no idea if that is going to be the truth or not."