At 4:25 pm on July 8, 1986, a 44 car Baltimore and Ohio railroad freight train, traveling at 45 miles per hour, bound south to Cincinnati, derailed near Miamisburg, Ohio, a small city with an industrial history in Montgomery County, southwest of Dayton. Fifteen of the cars derailed on a bridge; these were tank cars containing yellow phosphorus, molten sulfur and tallow. Carrying a chemical used to make rat poison, fireworks and luminescent coatings, one tank car caught fire. This resulted in emission of an estimated high cloud of phosphorus. A subsequent incident caused the largest train accident-triggered evacuation at the time in the United States. The accident was the second major rail disaster in Miamisburg within an eight-year period. On September 10, 1978, 15 cars of a Conrail train derailed. Initial response and evacuation At 7:00 pm city manager Dennis Kissinger declared a state of emergency. Approximately 17,500 people were evacuated from Miamisburg and other Montgomery County locales, including West Carrollton, Moraine and Jefferson Township. Seven hospitals in the area treated approximately 140 people for minor injuries such as eye, lung and skin irritation. Ron Parker, the city director of development said that the fire department indicated that the fire from the tankcar with the phosphorus was extinguished shortly after 10:00 pm. However, he said that three other freight cars were continuing to burn. The first of the evacuees returned to Moraine beginning at 10:00 pm that same evening. Governor Dick Celeste came to Miamisburg that evening to speak with area officials. Second rupture and evacuation By the following night, Wednesday, July 9, residents returning home. Firefighters continued their efforts to end the fires. A portion of the bridge broke, a car shifted, was punctured, and again phosphorus was ignited, sending out more smoke. The Associated Press reported that in a few hours 25,000 to 40,000 people evacuated from the vicinity in a second evacuation, at that time, the largest evacuation in U.S. history from a train accident according to William E. Loftus, executive director of the Federal Railroad Administration. This was also the largest evacuation in Ohio history. Initially attempts were made to use the University of Dayton Arena, however, it did not have sufficient air conditioning. Evacuees were sheltered at various schools and the Dayton Convention Center. In the coming days, the area was split into different zones, varying by danger: a Caution Zone, an Irritant Zone