The Great Molasses Flood, also known as the Boston Molasses Disaster, was a disaster that occurred on January 15, 1919, in the North End neighborhood of Boston, Massachusetts. A large storage tank filled with of molasses, weighing approximately, burst, and the resultant wave of molasses rushed through the streets at an estimated , killing 21 people and injuring 150. The event entered local folklore and residents claimed for decades afterwards that the area still smelled of molasses on hot summer days. Flood Molasses can be fermented to produce ethanol, the active ingredient in alcoholic beverages and a key component in munitions. The disaster occurred at the Purity Distilling Company facility at 529Commercial Street near Keany Square. A considerable amount of molasses had been stored there by the company, which used the harborside Commercial Street tank to offload molasses from ships and store it for later transfer by pipeline to the Purity ethanol plant situated between Willow Street and Evereteze Way in Cambridge, Massachusetts. The molasses tank stood tall and in diameter, and contained as much as . On January 15, 1919, temperatures in Boston had risen above , climbing rapidly from the frigid temperatures of the preceding days, and the previous day, a ship had delivered a fresh load of molasses, which had been warmed to reduce its viscosity for transfer. Possibly due to the thermal expansion of the older, colder molasses already inside the tank, the tank burst open and collapsed at approximately 12:30p.m. Witnesses reported that they felt the ground shake and heard a roar as it collapsed, a long rumble similar to the passing of an elevated train; others reported a tremendous crashing, a deep growling, "a thunderclap-like ", and a sound like a machine gun as the rivets shot out of the tank. The density of molasses is about , 40 percent more dense than water, resulting in the molasses having a great deal of potential energy. The collapse translated this energy into a wave of molasses high at its peak, moving at . The wave was of sufficient force to drive steel panels of the burst tank against the girders of the adjacent Boston Elevated Railway's Atlantic Avenue structure and tip a streetcar momentarily off the El's tracks. Stephen Puleo describes how nearby buildings were swept off their foundations and crushed. Several blocks were flooded to a depth of . Puleo quotes a Boston Post