Crews are testing the water and air quality along a stretch of the Yellowstone River where train cars carrying hazardous materials fell into the waterway following a bridge collapse. Seven cars carrying hot asphalt and molten sulfur fell into the rushing river Saturday morning in a rural area near the town of Columbus. The extent of the danger posed to the river isn't known, but a spokesperson for the train's operator, Montana Rail Link, says modeling suggests that the substances aren't likely to move very far downstream. The Environmental Protection Agency says toxic gases haven't been detected in the air.
