The Great Molasses Flood occurred on January 15, 1919, in the North End neighborhood of Boston, Massachusetts. A large molasses storage tank burst sending a wave of the sticky sweetener rushing through the streets at an estimated 35 mph. It killed 21 people and injured 150.
The tank holding the molasses was 50 feet tall, 90 feet in diameter, and contained as much as 2,300,000 gallons at the time of the collapse. Witnesses say that there were sounds like machine gun fire as the rivets shot of the sides of the tank. The collapse unleashed an immense wave of molasses between 8 and 15 feet high. Buildings were swept off their foundations and crushed. The molasses wave was of sufficient force to break the girders of the adjacent Boston Elevated Railway’s structure and lift a train off its tracks.
Here is the scene described by author Stephen Puleo:
“Molasses, waist deep, covered the streets and swirled and bubbled about the wreckage. Here and there struggled a form, whether it was animal or human being was impossible to tell. Only an upheaval, a thrashing about in a sticky mass, showed where any life was…..Horses died like so many flies on sticky fly-paper. The more they struggled, the deeper in the mess they were ensnared. Human being, man and women, suffered likewise.”
Several factors that occurred on that day and the previous days might have contributed to the disaster. The tank was poorly constructed and insufficiently tested. One of the overseers at the construction of the tank failed to do basic safety tests, such as filling the tank with water to check for leaks. The tank actually did leak when they filled it with molasses but they painted it brown to hide the leaks.
It took over 87,000 man hours to remove the molasses from the cobblestone streets, theaters, businesses, automobiles, and homes. The harbor was still brown with molasses until summer.
The event has entered local folklore, and residents claim that on hot summer days, the area still smells of molasses.