Nitroglycerin (NG), (united states spelling) also known as nitroglycerine, (UK spelling), trinitroglycerin, trinitroglycerine, 1,2,3-trinitroxypropane and glyceryl trinitrate, is a heavy, colorless, oily, explosive liquid obtained by nitrating glycerol. Since the 1860s, it has been used as an active ingredient in the manufacture of explosives, specifically dynamite, and as such is employed in the construction and demolition industries.