Check out the app "Cargo Decoder" - incorporates the DOT Emergency Response Guide - just "dial in" the UN number on a vehicle to see what they are carrying. And regarding fuel oil and diesel having the same number - it's because in an emergency they both behave the same way - we don't really care what the substance is - just what it will do!!! http://www.strategiesinsoftware.com/current-projects/cargo-decoder Scott