The train cars were carrying hot asphalt and molten sulfur, Stillwater County Disaster and Emergency Services said. Officials shut down drinking water intakes downstream while they evaluated the danger after the 6 a.m. accident. An Associated Press reporter witnessed a yellow substance coming out of some of the tank cars. David Stamey, the county's chief of emergency services, said there was no immediate danger for the crews working at the site, and the hazardous material was being diluted by the swollen river. There were three asphalt cars and four sulfur cars in the river.