The easy answer is that the emergency management process is all-encompassing. The transportation of dangerous goods may be identified as one of the key elements within a municipality because what they do is that they go through a HIRA process, the hazard identification and risk assessment process, and they identify probability and frequency of various issues. Depending on location, flooding may be included in that, tornadoes, hurricanes, and of course, the man-made ones.
On April 29th, 2014. See this statement in context.