A Sticky Tsunami–The Great Molasses Flood of 1919

The aftermath of the Boston Molasses Flood.

The aftermath of the Boston Molasses Flood.

The news cycle these days regularly reports on the dangers of food. From America’s soaring obesity rates, to the dangers of so-called “Franken-foods”, to recalls of contaminated food products, it seems that these days even the simple act of eating is a risky proposition.

Of course, the situation today is arguably far better than what people faced through most of human history. After all, our meals come to the grocery store already slaughtered–odds are, your dinner isn’t going to kill you before it gets to your plate, unlike our hunter-gatherer ancestors. Today the worry is more related to the health of foods–especially the additives put into foods–rather than the difficulties in finding it.

But food products can be deadly long before they reach our plates. Some of the strangest disasters in history center around rogue food products bursting from shoddily constructed holding containers and wreaking havoc on an unsuspecting public. One such incident occurred on January 15, 1919, in the North End of Boston, when a huge molasses storage tank exploded and unleashed a wave of sticky, sweet mayhem that is known to history as the Great Molasses Flood.


Death by molasses

When patrolman Frank McManus woke up on January 15, he could not have guessed that he would become part of one of the strangest incidents in history. Officer McManus was giving his daily report via a call box on Commercial street when a sound like gunfire ripped through the air, followed by a horrible grating noise. The startled officer turned to see a five-story high metal storage tank rip open, flinging steel fragments and rivets through the air. McManus relayed the stunning sight to his fellow officers at the precinct station, urging them to send all available rescue personnel.

Meanwhile, 2 million gallons of molasses tore down the streets of Boston’s North end at 35 miles an hour. The molasses–a thick, viscous, sticky substance–formed a massive front of destruction, shoving buildings off their foundation, swamping freight cars, and trapping man and beast alike within its gooey grasp. The wave tore down a city building where unsuspecting workers were sitting down for lunch. A section of tank wall fell onto a nearby firehouse, demolishing the building and burying three fire fighters in the ruins.

The viscous flood spread out over a large radius, miring everything in its path in its sticky embrace. All told, the disaster killed 21 people and injured another 150.  Half were crushed by debris or drowned in molasses that day, while the other half died from their injuries in the weeks to come. When the sweet tsunami ended, it left a stunned city and a coating of molasses two or three feet deep. Bostonians immediately began to clean up the mess, using sand and salt water sprayed from fire boats on the bay. While clean up efforts were underway, investigators attempted to answer the burning question on everyone’s mind: how could this happen?


Corporate negligence and shoddy construction

An elevated rail line damaged in the flood.

An elevated rail line damaged in the flood.

A long legal battle took place after the disaster, including a number of lawsuits. Several possible reasons for the flood emerged as the proceedings wore on, but one scenario has become generally accepted as an explanation. On July 13, 1919, the storage tank was filled to capacity. In the hot months that followed through the cold winter months leading up to that fateful January day, the molasses fermented, releasing carbon dioxide. United States Industrial Alcohol Co., the owner of the tank, was found to be at fault, as it had neglected maintenance on the tank, ignoring such problems as leaks and signs of structural instability.  Long story short, a combination of negligence and shoddy construction led to the deaths of 21 people on that oddly warm January day.

The Great Molasses Flood of 1919 remains among the most bizarre disasters in history, due in no small part to the strange substance at the heart of the disaster. Molasses is hardly a deadly substance–in fact, it has gained a new-found reputation these days as a natural alternative to processed sugar, which is believed by many to be at the center of today’s obesity epidemic. But molasses has unique properties that made it deadly that January day. It is a non-Newtonian fluid, meaning that its viscosity is depending upon the forces applied to it. Ketchup is a good example of such a substance. Ketchup remains in the bottle until you squeeze it out, and then it settles into a gooey mass on your plate. In a similar way, the molasses was “squeezed” out of the tank by mounting pressure from carbon dioxide, making it surge out of its container. Then when the force was removed, the molasses settled into its normal state, trapping people and animals within.

Another quirk of molasses made it deadly during the flood. Simply put, molasses is far more viscous than water, making swimming almost impossible. A person attempting to swim in molasses would find themselves only pushing the molasses back and forth without actually moving themselves forward. They end up only getting themselves more trapped, like attempting to struggle their way out of quick sand. Even rescuers found themselves quickly trapped in a quagmire when trying to get to victims.

In the end, due to its properties molasses turned out to be the “perfect” material to cause a bizarre disaster. Boston, always strong, moved on from the disaster as it always has. For the next eighty years, a reminder hung in the air during summer months–the molasses had permeated the stones and soil, and when the summer heat was high, the scent of molasses would hang heavy in the air. These days, the scent is gone, and all that remains is a plaque commemorating one of the strangest disasters in history.


Jabr, Ferris. “The Science of the Great Molasses Flood.” ScientificAmerican.com. July 17, 2013. Scientific American. May 17, 2015. http://www.scientificamerican.com/article/molasses-flood-physics-science/?page=1

Park, Edwards. “Without Warning, Molasses in January Surged over Boston.” Smithsonian 14, number 8 (November 1983), pgs. 213-230. Retrieved from: http://edp.org/molpark.htm

“12 Killed When Tank of Molasses Explodes.” The New York Times. January 16, 1919. Retrieved from: http://query.nytimes.com/mem/archive-free/pdf?_r=1&res=9B04E4D71339E13ABC4E52DFB7668382609EDE&oref=slogin

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  1. Pingback: Tararre–France’s Most Infamous Glutton | Oddly Historical

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