Urea, or carbamide, is an organic compound with the chemical formula (NH2)2CO that is synthesized from natural gas, not urine as frequently misstated. The molecule has two amine (-NH2) residues joined by a carbonyl (-CO-) functional group. Urea is the 14th highest volume chemical produced in the US. The primary use for urea is as a macronutrient ingredient in fertilizers where it provides a ready source of nitrogen. The ethanol fuel formulas have had an affect on urea demand because corn is a very fertilizer intensive crop. Other uses include urea-formaldehyde resins; melamine production; deicers; and flue gas denitrification. In recent years, urea has seen exponential growth in clean diesel systems such as the Bluetec system.