af347763___Inc____SCR___Facts_about_SCR__THE_TRUTH
[COMPETITOR RELEASED MYTHS] MYTH: DEF is toxic. [THE TRUTH] 
FACT: DEF does not become toxic at any temperature. It is a solution of 32.5 percent urea and purified water, which breaks down into common ammonia during a chemical reaction. The SCR element converts NOx and ammonia into nitrogen gas and water vapor. These harmless elements pass over a secondary catalyst to convert any leftover traces of ammonia before the exhaust leaves the system.
Cardinal Bus Sales & Service, Inc. - SCR - Facts about SCR
THE TRUTH