For days, large plumes of smoke containing vinyl chloride, phosgene, hydrogen chloride and other gases were emitted during a controlled release and burn, prompting officials to issue mandatory evacuation orders in a one-mile radius of the crash site. Although the controlled releases were considered \"low-level,\" the inhalation of fumes of vinyl chloride could cause dizziness, nausea, headache, visual disturbances, respiratory problems and other health-related issues, Ashok Kumar, a professor in the University of Toledo's department of civil and environmental engineering, told ABC News. It is \"absolutely critical\" for people to follow evacuation orders of any kind, but especially when having to do with \"highly toxic\" chemicals that could be deadly with high elevations of exposure, Karen Dannemiller, professor in the college of engineering and college of public health at the Ohio State University, told ABC News