U.S. Salt does not sell Urea.
Urea is more of a fertilizer. It is 47% nitrogen by weight, and is very soluble in water. Many landscapers use it for fertilizing. It is used at airports for de-icing a lot, because it is not corrosive to metals. Greater amounts of urea are required to melt as much and as fast as Calcium and Salt do. Sold in bags only. A friend tried some on his lawn this past Spring, since he had it left over from the winter. He didn't realize how high the nitrogen level was. He burned his whole lawn. In 2 weeks, he had a dirt patch where grass used to be. A lot of watering to leach the soil was necessary after this.
Urea is a common ice melters that is often perceived as safe products to use around vegetation. It needs to be used at a slightly higher rate of application, with Urea melting to 15o F. Urea does not contain chlorides, so it is less corrosive and safer for use on concrete containing rebar and around steel structures. This is one of the preferred ice melters for airports.