The Great Molasses Flood Of 1919

A photo showing the aftermath of the Great Molasses Flood.

On January 15th, 1919, Boston's vibrant North End was going about its typical routine when, without warning, the ordinary transformed into a tragic yet unpredictable disaster: the Great Molasses Flood. The flood of molasses wreaked havoc on the neighborhood at speeds of up to 35 mph, unfortunately causing 150 injuries and taking 21 lives. The story starts in 1915, when a massive steel tank was built along Boston's waterfront on Commercial Street, with the purpose of storing fermented molasses to create industrial alcohol. Pre-prohibition, the alcohol industry was incredibly profitable, as people drank during almost every meal. This particular tank was as enormous as the demand for molasses; it measured over 50 feet high and 90 feet wide, holding up to 2.5 million gallons of molasses. So, how could something so grand falter in such a deadly way?

Looking back at this period in history, after the First World War, America was concerned not only with saving grain for hungry families but also with the dangers of heavy drinking in American society. Led by figures such as Wayne Wheeler, Carrie Nation, and Ella Boolean, the Prohibition movement, which eventually led to the Eighteenth Amendment, proposed a complete alcohol ban in late 1919. However, since Prohibition hadn't been passed just yet, the company that operated the tank, the Purity Distilling Company, decided to increase production so they wouldn't go out of business once alcohol was banned.

The company disregarded the fact that the tank had been leaking from the start. Authors at the time accused the company of trying to produce as much as possible, even willing to put lives at danger, so they wouldn't have to close operations after Prohibition, which was coincidentally passed the day following the tragedy. Moreover, evidence revealed that the person who conducted the safety tests, Arthur Jell, had no engineering experience and ignored the facts: the tank creaked and groaned when it was full, the rivets were loose, and the leakage was so bad that people would come to collect leaking molasses to bring home. Interestingly, a 2014 investigation led by structural engineer Ronald Mayville found that the tank's steel was only about half as thick as it should have been, even by the loose standards of the 1910s. Its composition was also low in essential alloying elements like manganese. This meant that the steel was incredibly brittle, slowly cracking the tank at stress points.

This specific January afternoon created the perfect recipe for disaster. The unusually warm winter weather on that day drastically increased the pressure exerted by the molasses, as air temperatures had increased from a mere 2°F the day before to 41°F, causing the molasses to expand against the brittle walls of the tank. The cold weather in the preceding days had also prompted the workers to add more warm molasses to make it less viscous for mixing and processing. According to fluid dynamics, a less viscous liquid has less internal resistance, so when the tank burst, the molasses was able to quickly spread and flow over objects.

Anyway, it was around 12:30 P.M. when the tank burst. Witnesses reported the ground shaking as though a train had passed by, but it was, in reality, caused by the sheer density and speed of the molasses barreling down the streets. Others heard "a thunderclap-like bang" as the rivets shot out of the tank like a machine gun firing.

The immediate response from the people was understandably as confused and horrified as it would be if someone saw 2.3 million gallons of molasses spilled all through the streets. The first responders were a group of about a hundred cadets from the Massachusetts Nautical School, and they had been standing at a nearby pier. They were knee-deep in the molasses as they were trying to pull people out. The Boston Police, Red Cross, and Army and Navy personnel soon arrived. The rescue efforts lasted for 4 days, until the responders gave up. They stopped the rescue efforts because the molasses had glazed over everything, making it hard to identify and retrieve victims. Throughout the response, the temperature had dropped significantly, increasing the viscosity of the molasses, making it harder and more resistant. The heavy, cold, and sticky molasses weighed down the majority of victims, hiding them from rescuers or, in some cases, suffocating them as their throats became blocked with molasses.

The molasses engulfed everything in its path, including animals such as horses, dogs, and cats. To quote a Boston Post report, "Horses died like so many flies on sticky fly-paper. The more they struggled, the deeper in the mess they were ensnared." The sticky, nearly solid molasses strongly clung to the animals and people, and it proved to be just as lethal to animals as to humans.

Cleanup was no easy task. It took a long time for the cleanup crew to use salt water to wash away the molasses and move sand to absorb the water and molasses. After about three or four months, as the crew was collecting water to clean the streets, they found more victims, who were washed away by the molasses and pushed into the Boston Harbor. Cleaning the Great Molasses Flood was a laborious and slow process that involved thoroughly washing the streets, homes, subways, and even telephone booths. The harbor was brown with molasses until summer, with local news reporting, "Everything that a Bostonian touched was sticky."

In the aftermath, over a hundred Boston residents filed a class-action lawsuit against the United States Industrial Alcohol Company (USIA), which owned the Purity Distilling Company. The USIA was held accountable for poor safety standards and construction. This lawsuit helped strengthen the Prohibition movement by showing the dangers of America's alcohol industry and revealing the poor industry standards that had caused the flood. Historically, the lawsuit against the USIA was the first of its kind in Massachusetts, and it set important precedents for corporate accountability, regulatory reforms, and safety standards, helping shape American production practices today.